From 58007c0084b2a4411da57811e74290365ac80f04 Mon Sep 17 00:00:00 2001
From: Sy03 <1370724210@qq.com>
Date: Wed, 12 Aug 2026 07:00:35 +0800
Subject: [PATCH] [New Model] Support IndexTTS 2.5 (#5957)

Signed-off-by: Sysy <1370724210@qq.com>
Co-authored-by: Yueqian Lin <70319226+linyueqian@users.noreply.github.com>
---
 .buildkite/intel/pipeline-intel.yml           |    2 +-
 .buildkite/intel/scripts/run-xpu-test.sh      |   17 +-
 benchmarks/tts/README.md                      |   28 +
 benchmarks/tts/bench_tts.py                   |   33 +-
 benchmarks/tts/model_configs.yaml             |   11 +
 docker/Dockerfile.xpu                         |    9 +-
 docs/models/supported_models.md               |    1 +
 .../text_to_speech/README.md                  |   37 +-
 .../text_to_speech/indextts2/end2end.py       |  114 +-
 .../online_serving/text_to_speech/README.md   |   48 +-
 .../text_to_speech/indextts2/run_server.sh    |   27 +-
 .../text_to_speech/indextts2/speech_client.py |   39 +-
 pyproject.toml                                |   11 +
 recipes/IndexTeam/IndexTTS-2_5.md             |  308 +++++
 recipes/README.md                             |    1 +
 tests/benchmarks/test_bench_tts_cli.py        |   36 +
 tests/config/test_config_factory.py           |   10 +
 .../sched/test_omni_scheduling_coordinator.py |    1 +
 tests/engine/test_arg_utils.py                |  152 +++
 .../test_async_omni_engine_stage_init.py      |   50 +-
 tests/engine/test_omni_request.py             |    1 +
 .../openai_api/test_serving_speech.py         |  110 +-
 .../openai_api/test_tts_adapter.py            |  122 ++
 .../openai_api/test_tts_detection.py          |   20 +-
 .../test_indextts2_run_server.py              |  108 ++
 .../models/indextts2/__init__.py              |    0
 .../test_configuration_and_pipeline.py        |   89 ++
 .../models/indextts2/test_dit_cuda_graph.py   |   75 ++
 .../models/indextts2/test_enhanced_codec.py   |   84 ++
 .../models/indextts2/test_prompt_utils.py     |  202 ++++
 .../models/indextts2/test_recipe_defaults.py  |   14 +
 .../models/indextts2/test_s2mel_v2_5.py       | 1066 +++++++++++++++++
 .../indextts2/test_stage_input_processor.py   |   53 +
 .../models/indextts2/test_talker_v2_5.py      |  476 ++++++++
 .../models/indextts2/test_tokenizer_v2_5.py   |  244 ++++
 .../models/indextts2/test_wavenet_ragged.py   |  196 +++
 .../qwen3_tts/test_code_predictor_dtype.py    |   23 +
 .../stage_input_processors/test_indextts2.py  |   86 +-
 tests/test_indextts2_optional_dependencies.py |  155 +++
 tests/utils/test_mm_outputs_partition.py      |   31 +
 tests/worker/test_omni_gpu_model_runner.py    |   44 +
 vllm_omni/config/pipeline_registry.py         |    6 +-
 .../core/sched/omni_scheduling_coordinator.py |    5 +-
 vllm_omni/deploy/indextts2_5.yaml             |   64 +
 vllm_omni/deploy/qwen2_5_omni.yaml            |   12 +-
 vllm_omni/engine/arg_utils.py                 |   14 +-
 vllm_omni/engine/stage_init_utils.py          |   22 +-
 vllm_omni/entrypoints/openai/api_server.py    |    8 +-
 .../entrypoints/openai/protocol/audio.py      |   13 +-
 vllm_omni/entrypoints/openai/serving_chat.py  |    9 +-
 .../entrypoints/openai/serving_speech.py      |   16 +-
 .../entrypoints/openai/tts_adapters/base.py   |    2 +
 .../openai/tts_adapters/indextts2.py          |   86 +-
 .../models/common/qwen3_code_predictor.py     |    5 +-
 .../models/indextts2/codec/__init__.py        |    7 +
 .../models/indextts2/codec/models.py          |  138 +++
 .../models/indextts2/codec/quantizer.py       |   91 ++
 .../models/indextts2/codec/vocos.py           |   82 ++
 .../indextts2/configuration_indextts2.py      |   47 +
 .../models/indextts2/dit_cuda_graph.py        |   55 +-
 .../indextts2/indextts2_s2mel_decoder.py      |  901 +++++++++++---
 .../models/indextts2/indextts2_talker.py      |  471 ++++++--
 .../models/indextts2/pipeline.py              |   38 +-
 .../models/indextts2/preprocess_utils.py      |  145 ++-
 .../models/indextts2/prompt_utils.py          |   62 +-
 .../models/indextts2/s2mel/modules/commons.py |    4 +-
 .../s2mel/modules/diffusion_transformer.py    |   23 +-
 .../indextts2/s2mel/modules/flow_matching.py  |  136 ++-
 .../indextts2/s2mel/modules/gpt_fast/model.py |   67 +-
 .../models/indextts2/s2mel/modules/wavenet.py |   71 +-
 .../models/indextts2/text_processing_v2_5.py  |  328 +++++
 .../models/indextts2/tokenizer_v2_5.py        |  286 +++++
 vllm_omni/model_executor/models/registry.py   |   11 +
 .../stage_input_processors/indextts2.py       |  170 ++-
 vllm_omni/request.py                          |    4 +
 vllm_omni/utils/mm_outputs.py                 |   54 +
 vllm_omni/worker/gpu_ar_model_runner.py       |   55 +-
 77 files changed, 7123 insertions(+), 519 deletions(-)
 create mode 100644 recipes/IndexTeam/IndexTTS-2_5.md
 create mode 100644 tests/examples/online_serving/test_indextts2_run_server.py
 create mode 100644 tests/model_executor/models/indextts2/__init__.py
 create mode 100644 tests/model_executor/models/indextts2/test_configuration_and_pipeline.py
 create mode 100644 tests/model_executor/models/indextts2/test_dit_cuda_graph.py
 create mode 100644 tests/model_executor/models/indextts2/test_enhanced_codec.py
 create mode 100644 tests/model_executor/models/indextts2/test_prompt_utils.py
 create mode 100644 tests/model_executor/models/indextts2/test_recipe_defaults.py
 create mode 100644 tests/model_executor/models/indextts2/test_s2mel_v2_5.py
 create mode 100644 tests/model_executor/models/indextts2/test_stage_input_processor.py
 create mode 100644 tests/model_executor/models/indextts2/test_talker_v2_5.py
 create mode 100644 tests/model_executor/models/indextts2/test_tokenizer_v2_5.py
 create mode 100644 tests/model_executor/models/indextts2/test_wavenet_ragged.py
 create mode 100644 tests/test_indextts2_optional_dependencies.py
 create mode 100644 vllm_omni/deploy/indextts2_5.yaml
 create mode 100644 vllm_omni/model_executor/models/indextts2/codec/__init__.py
 create mode 100644 vllm_omni/model_executor/models/indextts2/codec/models.py
 create mode 100644 vllm_omni/model_executor/models/indextts2/codec/quantizer.py
 create mode 100644 vllm_omni/model_executor/models/indextts2/codec/vocos.py
 create mode 100644 vllm_omni/model_executor/models/indextts2/text_processing_v2_5.py
 create mode 100644 vllm_omni/model_executor/models/indextts2/tokenizer_v2_5.py

diff --git a/.buildkite/intel/pipeline-intel.yml b/.buildkite/intel/pipeline-intel.yml
index acb135101..2a1507456 100644
--- a/.buildkite/intel/pipeline-intel.yml
+++ b/.buildkite/intel/pipeline-intel.yml
@@ -10,7 +10,7 @@ steps:
           DOCKER_BUILDKIT: "1"
           # Buildkite will automatically replace this with the actual commit hash
           VLLM_IMAGE_TAG: "${BUILDKITE_COMMIT}"
-          VLLM_VERSION: "v0.26.0"
+          VLLM_VERSION: "v0.27.0"
         priority: 100
         timeout_in_minutes: 60
         soft_fail: false
diff --git a/.buildkite/intel/scripts/run-xpu-test.sh b/.buildkite/intel/scripts/run-xpu-test.sh
index 6b40d58fb..742e39b78 100755
--- a/.buildkite/intel/scripts/run-xpu-test.sh
+++ b/.buildkite/intel/scripts/run-xpu-test.sh
@@ -34,8 +34,23 @@ docker_build() {
     docker build "${out[@]}" "$@" -f docker/Dockerfile.xpu .
 }
 
+build_vllm_base() (
+    local vllm_source_dir
+    vllm_source_dir=$(mktemp -d)
+    trap 'rm -rf "${vllm_source_dir}"' EXIT
+
+    git clone --depth 1 --branch "${VLLM_VERSION}" \
+        https://github.com/vllm-project/vllm "${vllm_source_dir}"
+
+    local out=("${export_args[@]/'{{IMAGE}}'/${base_image_name}}")
+    docker build "${out[@]}" \
+        --target vllm-openai \
+        -f "${vllm_source_dir}/docker/Dockerfile.xpu" \
+        "${vllm_source_dir}"
+)
+
 if [ -z "$(docker images -q "${base_image_name}")" ]; then
-    docker_build "${base_image_name}" --target vllm-base --build-arg "VLLM_VERSION=${VLLM_VERSION}"
+    build_vllm_base
 fi
 
 # Try building the docker image
diff --git a/benchmarks/tts/README.md b/benchmarks/tts/README.md
index f6930a866..d3a0f9676 100644
--- a/benchmarks/tts/README.md
+++ b/benchmarks/tts/README.md
@@ -139,6 +139,34 @@ python benchmarks/tts/bench_tts.py \
     --output-dir ./results
 ```
 
+#### Fixed IndexTTS 2.5 performance sweep
+
+IndexTTS 2.5 is registered in `model_configs.yaml` like the other TTS models.
+Use `--served-model-name` when the server was launched from a local native
+bundle instead of the registry key. The command below reproduces the acceptance
+workload: Seed-TTS Eval EN, `n=500`, concurrency `4/8/16/32`, five warmups, and
+dataset seed 0.
+
+```bash
+python benchmarks/tts/bench_tts.py \
+    --model IndexTeam/IndexTTS-2.5 \
+    --served-model-name /path/to/indextts-2.5 \
+    --task voice_clone --locale en \
+    --dataset-path /path/to/seedtts_testset \
+    --host 127.0.0.1 --port 8092 \
+    --concurrency 4 8 16 32 \
+    --num-prompts 500 --num-warmups 5 \
+    --output-dir ./results/indextts2_5 \
+    -- \
+    --tokenizer /path/to/indextts-2.5/qwen0.6bemo4-merge \
+    --seed 0 --metric-percentiles 50,95,99 --disable-tqdm --save-detailed
+```
+
+The wrapper benchmarks an already-running server. For reproducible quality
+comparisons, add `--request-seed 42`; production-performance runs should omit
+it. The trailing `--seed 0` controls Seed-TTS row selection rather than model
+sampling.
+
 ### 4. Plot a sweep
 
 ```bash
diff --git a/benchmarks/tts/bench_tts.py b/benchmarks/tts/bench_tts.py
index c79d74a31..f8c1676be 100644
--- a/benchmarks/tts/bench_tts.py
+++ b/benchmarks/tts/bench_tts.py
@@ -84,12 +84,17 @@ def build_bench_args(
     result_filename: str | None,
     extra_cli_args: list[str],
     output_len: int | None = None,
+    served_model_name: str | None = None,
+    num_warmups: int = 2,
+    request_seed: int | None = None,
 ) -> list[str]:
     """Build the ``vllm bench serve --omni`` command for one (task, concurrency) run."""
     dataset_name = _TASK_TO_DATASET[task]
     backend: str = model_cfg["backend"]
     endpoint: str = model_cfg["endpoint"]
-    task_extra_body: dict[str, Any] = (model_cfg.get("task_extra_body") or {}).get(task) or {}
+    task_extra_body: dict[str, Any] = dict((model_cfg.get("task_extra_body") or {}).get(task) or {})
+    if request_seed is not None:
+        task_extra_body["seed"] = request_seed
 
     # Resolve dataset path
     if dataset_path:
@@ -109,7 +114,7 @@ def build_bench_args(
         "--port",
         str(port),
         "--model",
-        model,
+        served_model_name or model,
         "--backend",
         backend,
         "--endpoint",
@@ -119,7 +124,7 @@ def build_bench_args(
         "--num-prompts",
         str(num_prompts),
         "--num-warmups",
-        "2",
+        str(num_warmups),
         "--percentile-metrics",
         "ttft,e2el,audio_rtf,audio_ttfp,audio_duration,audio_underrun",
     ]
@@ -152,7 +157,8 @@ def build_bench_args(
         if result_filename:
             cmd += ["--result-filename", result_filename]
 
-    cmd += extra_cli_args
+    passthrough = extra_cli_args[1:] if extra_cli_args[:1] == ["--"] else extra_cli_args
+    cmd += passthrough
     return cmd
 
 
@@ -225,6 +231,12 @@ def main() -> None:
     parser.add_argument(
         "--model", required=True, help="HuggingFace model ID (e.g. Qwen/Qwen3-TTS-12Hz-1.7B-CustomVoice)"
     )
+    parser.add_argument(
+        "--served-model-name",
+        default=None,
+        help="Model name/path accepted by the running server. Use this when --model selects a registry entry "
+        "but the server was launched from a local bundle path.",
+    )
     parser.add_argument("--task", default="all", help="Task type: voice_clone | default_voice | voice_design | all")
     parser.add_argument("--locale", default="en", choices=["en", "zh"])
     parser.add_argument("--concurrency", type=int, nargs="+", default=[1, 4], metavar="N")
@@ -236,6 +248,13 @@ def main() -> None:
         metavar="N",
         help="Number of prompts per run. If one value, applied to all concurrency levels.",
     )
+    parser.add_argument("--num-warmups", type=int, default=2, help="Warmup requests before each measured run")
+    parser.add_argument(
+        "--request-seed",
+        type=int,
+        default=None,
+        help="Optional model sampling seed added to every request body for reproducible quality runs",
+    )
     parser.add_argument(
         "--dataset-path", default=None, help="Root of seed-tts-eval dataset (required for voice_clone/default_voice)"
     )
@@ -256,6 +275,9 @@ def main() -> None:
     parser.add_argument("extra", nargs=argparse.REMAINDER, help="Extra args passed directly to vllm bench serve")
     args = parser.parse_args()
 
+    if args.num_warmups < 0:
+        parser.error("--num-warmups cannot be negative")
+
     model_configs = load_model_configs(Path(args.model_configs))
     if args.model not in model_configs:
         known = "\n  ".join(model_configs.keys())
@@ -308,6 +330,9 @@ def main() -> None:
                 result_filename=result_filename,
                 extra_cli_args=args.extra or [],
                 output_len=args.output_len,
+                served_model_name=args.served_model_name,
+                num_warmups=args.num_warmups,
+                request_seed=args.request_seed,
             )
             result = run_one_benchmark(cmd)
             if result is not None:
diff --git a/benchmarks/tts/model_configs.yaml b/benchmarks/tts/model_configs.yaml
index 2ec7addca..5450e8a7c 100644
--- a/benchmarks/tts/model_configs.yaml
+++ b/benchmarks/tts/model_configs.yaml
@@ -7,6 +7,17 @@
 # is tracked here.
 
 models:
+  IndexTeam/IndexTTS-2.5:
+    supported_tasks: [voice_clone]
+    backend: openai-audio-speech
+    endpoint: /v1/audio/speech
+    trust_remote_code: true
+    task_extra_body:
+      voice_clone:
+        extra_params:
+          lang: en
+          text_normalization: true
+
   # -CustomVoice checkpoints lack speaker_encoder weights, so voice_clone is
   # NOT supported (an attempt raises ValueError from _extract_speaker_embedding
   # at model runtime).  Use -Base for voice_clone.
diff --git a/docker/Dockerfile.xpu b/docker/Dockerfile.xpu
index 5d298040c..65ae05dd3 100644
--- a/docker/Dockerfile.xpu
+++ b/docker/Dockerfile.xpu
@@ -88,7 +88,7 @@ ENV UV_EXTRA_INDEX_URL=${PIP_EXTRA_INDEX_URL}
 ENV UV_INDEX_STRATEGY="unsafe-best-match"
 ENV UV_LINK_MODE="copy"
 
-ARG VLLM_VERSION=v0.26.0
+ARG VLLM_VERSION=v0.27.0
 RUN git clone -b ${VLLM_VERSION} https://github.com/vllm-project/vllm
 WORKDIR /workspace/vllm
 
@@ -108,7 +108,7 @@ ENV VLLM_WORKER_MULTIPROC_METHOD=spawn
 
 RUN --mount=type=cache,target=/root/.cache/uv \
     uv pip uninstall triton triton-xpu && \
-    uv pip install triton-xpu==3.7.1 && \
+    uv pip install triton-xpu==3.7.2 && \
     uv pip install --no-build-isolation --no-deps .
 
 CMD ["/bin/bash"]
@@ -144,12 +144,13 @@ WORKDIR /workspace/vllm-omni
 COPY . .
 
 ENV VLLM_OMNI_TARGET_DEVICE=xpu
+# Keep the upstream oneCCL packages paired with the XPU torch runtime.
 RUN --mount=type=cache,target=/root/.cache/uv \
     uv pip install --no-build-isolation \
     --extra-index-url https://mirrors.ustc.edu.cn/pypi/simple/ \
     ".[dev]" && \
-    uv pip uninstall triton oneccl oneccl-devel && \
-    uv pip install triton-xpu==3.7.1 --reinstall
+    uv pip uninstall triton && \
+    uv pip install triton-xpu==3.7.2 --reinstall
 
 FROM vllm-omni AS vllm-omni-openai
 
diff --git a/docs/models/supported_models.md b/docs/models/supported_models.md
index add8b86b3..b9686047a 100644
--- a/docs/models/supported_models.md
+++ b/docs/models/supported_models.md
@@ -80,6 +80,7 @@ th {
 | `HiggsAudioV2ForConditionalGeneration` | Higgs-Audio v2 | `bosonai/higgs-audio-v2-generation-3B-base` | ✅︎ | | | | — |
 | `HiggsMultimodalQwen3ForConditionalGeneration` | Higgs-Audio v3 (TTS) | `bosonai/higgs-audio-v3-tts-4b` | ✅︎ | | | | [Published](https://recipes.vllm.ai/bosonai/higgs-audio-v3-tts-4b) |
 | `IndexTTS2TalkerForConditionalGeneration` | IndexTTS-2 | `IndexTeam/IndexTTS-2` | ✅︎ | | | | — |
+| `IndexTTS25TalkerForConditionalGeneration` | IndexTTS-2.5 | native `checkpoints/` bundle | ✅︎ | | | | [Repository](https://github.com/vllm-project/vllm-omni/blob/main/recipes/IndexTeam/IndexTTS-2_5.md) |
 | `NextStep11Pipeline` | NextStep-1.1 | `stepfun-ai/NextStep-1.1` | ✅︎ | ✅︎ | | ✅︎ | — |
 | `MiMoAudioModel` | MiMo-Audio-7B-Instruct | `XiaomiMiMo/MiMo-Audio-7B-Instruct` | ✅︎ | ✅︎ | | | — |
 | `MiMoV2ASRForCausalLM` | MiMo-V2.5-ASR | `XiaomiMiMo/MiMo-V2.5-ASR` | ✅︎ | ✅︎ | | | — |
diff --git a/examples/offline_inference/text_to_speech/README.md b/examples/offline_inference/text_to_speech/README.md
index 180ab9954..56135b55e 100644
--- a/examples/offline_inference/text_to_speech/README.md
+++ b/examples/offline_inference/text_to_speech/README.md
@@ -24,6 +24,7 @@ list of supported architectures across all modalities, see
 | Qwen3-TTS | `Qwen/Qwen3-TTS-12Hz-1.7B-{CustomVoice,VoiceDesign,Base}` | 2 (talker + code2wav) | ✓ (Base) | ✓ | 3 task variants | 24 kHz |
 | VoxCPM2 | `openbmb/VoxCPM2` | single (native AR) | ✓ | ✓ (online) | continuation | 48 kHz |
 | IndexTTS-2 | `IndexTeam/IndexTTS-2` | 2 (AR talker + S2Mel DiT + BigVGAN) | ✓ (required) | — | emotion control (`--emo-audio`, `--emo-text`, `--emo-vector`) | 22.05 kHz |
+| IndexTTS-2.5 | native `checkpoints/` bundle | 2 (AR talker + EnhancedCodec + S2Mel DiT + BigVGAN) | ✓ (required) | — | multilingual (`--lang`) + emotion control | 22.05 kHz |
 | Voxtral TTS | `mistralai/Voxtral-4B-TTS-2603` | varies | ✓ | ✓ | voice presets | 24 kHz |
 
 ## Common Quick Start
@@ -437,11 +438,14 @@ Streaming is exposed through the online OpenAI Speech API (`stream=true`). See [
 
 ---
 
-## IndexTTS-2
+## IndexTTS-2 and IndexTTS-2.5
 
-2-stage TTS pipeline (GPT AR talker + S2Mel CFM DiT + BigVGAN vocoder) at 22.05 kHz. Every request requires reference audio for zero-shot voice cloning. Supports emotion conditioning via audio, text, or 8-dim vector.
+Both versions use a 2-stage TTS pipeline and produce 22.05 kHz mono audio. Stage 0 is a GPT AR talker. IndexTTS-2 Stage 1 uses RepCodec semantic embeddings, GPT latent, S2Mel CFM/DiT, and BigVGAN. IndexTTS-2.5 replaces RepCodec with EnhancedCodec and uses the official code-only path (`use_gpt_latent=false`). Every request requires reference audio for zero-shot voice cloning.
 
 ### Quick start
+
+IndexTTS-2:
+
 ```bash
 python examples/offline_inference/text_to_speech/indextts2/end2end.py \
     --model IndexTeam/IndexTTS-2 \
@@ -449,6 +453,24 @@ python examples/offline_inference/text_to_speech/indextts2/end2end.py \
     --ref-audio /path/to/reference.wav
 ```
 
+IndexTTS-2 uses its existing frontend and does not require the IndexTTS-2.5 text dependencies. Before running IndexTTS-2.5, install its optional frontend dependencies:
+
+```bash
+pip install 'vllm-omni[indextts2]'
+```
+
+IndexTTS-2.5 with a native repository/lab bundle whose model root contains `checkpoints/`:
+
+```bash
+python examples/offline_inference/text_to_speech/indextts2/end2end.py \
+    --model /path/to/indextts-2.5 \
+    --model-version 2.5 \
+    --lang ja \
+    --text "こんにちは、音声合成のテストです。" \
+    --ref-audio /path/to/reference.wav
+
+```
+
 ### Emotion control
 ```bash
 # Emotion from reference audio
@@ -474,10 +496,13 @@ python examples/offline_inference/text_to_speech/indextts2/end2end.py \
 ```
 
 ### Notes
-- `--ref-audio` is **required** — IndexTTS-2 does not support text-only synthesis.
-- Stage 0 (AR Talker): GPT-2 generates mel codes from text + reference audio.
-- Stage 1 (S2Mel + BigVGAN): CFM DiT converts mel codes to waveform at 22.05 kHz.
-- Deploy config: `vllm_omni/deploy/indextts2.yaml`. Stage 1 runs with `enforce_eager: true` (DiT has dynamic shapes).
+- `--ref-audio` is **required** — neither version provides text-only synthesis.
+- IndexTTS-2.5 Stage 0 (AR Talker) generates mel codes from text + reference audio using plain vLLM sampling. It does not reproduce the official default `num_beams=3` beam search. For parity comparisons, run upstream with `num_beams=1`; output quality can differ from the official beam-search result.
+- IndexTTS-2.5 accepts language codes such as `zh`, `en`, `zhen` (mixed Chinese/English), `ja`, and `yue`. `Mandarin` is a vLLM-Omni convenience alias for `zh`. Japanese (`ja`) uses `fugashi` tokenization and produces audio, but it does not automatically expand numbers, dates, or percentages; write those inputs as readable Japanese text before calling the model. Use `--no-text-normalization` only when the input is already normalized.
+- A seed controls Stage 0 AR sampling and per-request CFM noise. Different concurrent batch compositions do not guarantee a bit-identical waveform.
+- Stage 1 (semantic codec + S2Mel + BigVGAN): CFM/DiT converts the complete semantic-code sequence to waveform.
+- Deploy configs: `vllm_omni/deploy/indextts2.yaml` and `indextts2_5.yaml`.
+- `async_chunk=false` is intentional for IndexTTS-2.5 correctness: S2Mel consumes the completed semantic sequence.
 
 ---
 
diff --git a/examples/offline_inference/text_to_speech/indextts2/end2end.py b/examples/offline_inference/text_to_speech/indextts2/end2end.py
index 858487ae1..084e2cc72 100644
--- a/examples/offline_inference/text_to_speech/indextts2/end2end.py
+++ b/examples/offline_inference/text_to_speech/indextts2/end2end.py
@@ -1,13 +1,16 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-"""Offline inference example for IndexTTS2 via vLLM-Omni.
+"""Offline inference example for IndexTTS 2.0 and 2.5 via vLLM-Omni.
 
-Two-stage pipeline: GPT AR (Stage 0) → S2Mel + BigVGAN (Stage 1).
+Two-stage pipeline: GPT AR (Stage 0) → semantic codec + S2Mel + BigVGAN
+(Stage 1).
 Output is 22050 Hz mono WAV.
 
 Usage:
   python end2end.py \
-    --model /path/to/IndexTeam/IndexTTS-2 \
+    --model /path/to/indextts-2.5 \
+    --model-version 2.5 \
+    --lang zh \
     --text "你好，这是一个语音合成测试。" \
     --ref-audio /path/to/ref.wav
 
@@ -47,6 +50,10 @@ def build_request(
     emo_alpha: float | None = None,
     use_emo_text: bool = False,
     use_random: bool = False,
+    model_type: str = "indextts2",
+    lang: str = "zh",
+    text_normalization: bool = True,
+    tokenizer_file: str | None = None,
 ) -> dict:
     additional: dict = {"text": [text]}
     if ref_audio_path:
@@ -63,12 +70,44 @@ def build_request(
         additional["use_emo_text"] = [True]
     if use_random:
         additional["use_random"] = [True]
+    if model_type == "indextts2_5":
+        additional["lang"] = [lang]
+        additional["text_normalization"] = [text_normalization]
+    prompt_kwargs = {
+        "model_type": model_type,
+        "lang": lang,
+        "text_normalization": text_normalization,
+    }
+    if tokenizer_file is not None:
+        prompt_kwargs["tokenizer_file"] = tokenizer_file
     return {
-        "prompt_token_ids": build_indextts2_prefill_prompt_ids(model, text),
+        "prompt_token_ids": build_indextts2_prefill_prompt_ids(
+            model,
+            text,
+            **prompt_kwargs,
+        ),
         "additional_information": additional,
     }
 
 
+def _get_stage0_tokenizer_file(omni: Omni) -> str | None:
+    """Read the effective tokenizer override from the resolved Stage 0 config."""
+    stage_configs = omni.stage_configs
+    if not stage_configs:
+        return None
+    engine_args = getattr(stage_configs[0], "engine_args", None)
+    if engine_args is None:
+        return None
+    hf_overrides = getattr(engine_args, "hf_overrides", None)
+    if hf_overrides is None and isinstance(engine_args, dict):
+        hf_overrides = engine_args.get("hf_overrides")
+    if hf_overrides is None:
+        return None
+    if hasattr(hf_overrides, "get"):
+        return hf_overrides.get("tokenizer_file")
+    return getattr(hf_overrides, "tokenizer_file", None)
+
+
 def save_audio(waveform: torch.Tensor, path: str, sample_rate: int = 22050) -> None:
     audio_np = waveform.float().numpy()
     sf.write(path, audio_np, sample_rate)
@@ -95,9 +134,14 @@ def extract_audio(mm: dict) -> tuple[torch.Tensor | None, int]:
 
 
 def main(args) -> None:
+    model_type = "indextts2_5" if args.model_version == "2.5" else "indextts2"
+    deploy_config = args.deploy_config
+    if deploy_config is None and args.model_version == "2.5":
+        repo_root = Path(__file__).resolve().parents[4]
+        deploy_config = str(repo_root / "vllm_omni" / "deploy" / "indextts2_5.yaml")
     omni = Omni(
         model=args.model,
-        deploy_config=args.deploy_config,
+        deploy_config=deploy_config,
         stage_init_timeout=args.stage_init_timeout,
     )
 
@@ -126,7 +170,7 @@ def main(args) -> None:
     print(f"Synthesizing: {args.text!r}")
     if args.ref_audio:
         print(f"  ref_audio: {args.ref_audio}")
-    inputs = build_request(
+    request_kwargs = dict(
         model=args.model,
         text=args.text,
         ref_audio_path=args.ref_audio,
@@ -136,7 +180,17 @@ def main(args) -> None:
         emo_alpha=args.emo_alpha,
         use_emo_text=args.use_emo_text,
         use_random=args.use_random,
+        model_type=model_type,
+        lang=args.lang,
+        text_normalization=args.text_normalization,
     )
+    if model_type == "indextts2_5":
+        tokenizer_file = _get_stage0_tokenizer_file(omni)
+        if tokenizer_file is not None:
+            request_kwargs["tokenizer_file"] = tokenizer_file
+    inputs = build_request(**request_kwargs)
+    if model_type == "indextts2_5":
+        inputs["additional_information"]["duration_factor"] = [1.0 / getattr(args, "speed", 1.0)]
 
     for i, omni_out in enumerate(omni.generate(inputs, sampling_params_list=sampling_params)):
         mm = omni_out.multimodal_output
@@ -154,8 +208,37 @@ def main(args) -> None:
 
 
 def parse_args():
-    parser = FlexibleArgumentParser(description="IndexTTS2 offline inference")
-    parser.add_argument("--model", required=True, help="HF model path for IndexTTS2.")
+    parser = FlexibleArgumentParser(description="IndexTTS 2.0/2.5 offline inference")
+    parser.add_argument(
+        "--model",
+        required=True,
+        help="HF model path or native bundle containing checkpoints/.",
+    )
+    parser.add_argument(
+        "--model-version",
+        choices=("2.0", "2.5"),
+        default="2.0",
+    )
+    parser.add_argument(
+        "--lang",
+        default="zh",
+        help=(
+            "IndexTTS 2.5 language code, for example zh/en/zhen/ja/yue; "
+            "zhen is mixed Chinese/English and Mandarin is a vLLM-Omni alias for zh."
+        ),
+    )
+    parser.add_argument(
+        "--no-text-normalization",
+        action="store_false",
+        dest="text_normalization",
+        help="Disable IndexTTS 2.5 text normalization.",
+    )
+    parser.add_argument(
+        "--speed",
+        type=float,
+        default=1.0,
+        help="IndexTTS 2.5 native synthesis speed in [0.5, 2.0]; 2.0 is faster.",
+    )
     parser.add_argument("--text", default="你好，这是IndexTTS2语音合成测试。")
     parser.add_argument("--ref-audio", required=True, help="Reference audio for voice cloning.")
     parser.add_argument("--emo-audio", default=None, help="Emotion reference audio.")
@@ -170,7 +253,15 @@ def parse_args():
     parser.add_argument("--emo-alpha", type=float, default=None, help="Emotion weight in [0, 1].")
     parser.add_argument("--use-emo-text", action="store_true", help="Infer emotion vector from emo-text or text.")
     parser.add_argument("--use-random", action="store_true", help="Use random emotion prototypes.")
-    parser.add_argument("--seed", type=int, default=None)
+    parser.add_argument(
+        "--seed",
+        type=int,
+        default=None,
+        help=(
+            "Seed Stage 0 AR sampling and per-request CFM noise; changing the "
+            "concurrent batch composition may still change the final waveform."
+        ),
+    )
     parser.add_argument(
         "--output-dir",
         default=os.path.join(
@@ -180,7 +271,10 @@ def parse_args():
     )
     parser.add_argument("--deploy-config", default=None)
     parser.add_argument("--stage-init-timeout", type=int, default=600)
-    return parser.parse_args()
+    args = parser.parse_args()
+    if args.model_version == "2.5" and not 0.5 <= args.speed <= 2.0:
+        parser.error("IndexTTS 2.5 --speed must be between 0.5 and 2.0")
+    return args
 
 
 if __name__ == "__main__":
diff --git a/examples/online_serving/text_to_speech/README.md b/examples/online_serving/text_to_speech/README.md
index b331966b3..2f9d84bf3 100644
--- a/examples/online_serving/text_to_speech/README.md
+++ b/examples/online_serving/text_to_speech/README.md
@@ -16,7 +16,8 @@ For the full list of supported architectures across all modalities, see
 |---|---|---|---|---|---|
 | Fish Speech S2 Pro | `fishaudio/s2-pro` | ✓ (`ref_audio`+`ref_text`) | ✓ (PCM stream) | — | ✓ |
 | GLM-TTS | `zai-org/GLM-TTS` | ✓ (`ref_audio`+`ref_text`, required) | ✓ (PCM stream) | — | ✓ |
-| IndexTTS-2 | `IndexTeam/IndexTTS-2` | ✓ (`ref_audio` or uploaded `voice`) | compat only, non-chunk | uploaded audio voice only; no presets | — |
+| IndexTTS-2 | `IndexTeam/IndexTTS-2` | ✓ (`ref_audio` or uploaded `voice`) | `stream=true` response, non-chunk | uploaded audio voice only; no presets | — |
+| IndexTTS-2.5 | native `checkpoints/` bundle | ✓ (`ref_audio` or uploaded `voice`) | `stream=true` response, non-chunk | uploaded audio voice only; no presets | — |
 | Ming-omni-tts | `inclusionAI/Ming-omni-tts-0.5B` | ✓ (`ref_audio` / `speaker_embedding`) | ✓ (PCM stream) | IP labels + structured `instructions` | — |
 | Ming-flash-omni-TTS | `Jonathan1909/Ming-flash-omni-2.0` | — (caption-controlled) | — | caption fields (`instructions`) | — |
 | MOSS-TTS-Nano | `OpenMOSS-Team/MOSS-TTS-Nano` | ✓ (`ref_audio` required) | ✓ (PCM stream) | — | ✓ |
@@ -138,15 +139,29 @@ bash examples/online_serving/text_to_speech/glm_tts/run_gradio_demo.sh
 
 ---
 
-## IndexTTS-2
+## IndexTTS-2 and IndexTTS-2.5
 
-2-stage TTS (GPT AR + S2Mel CFM DiT + BigVGAN) at 22.05 kHz. Requests use `ref_audio` for voice cloning, or an uploaded audio `voice` from `/v1/audio/voices`. Supports emotion conditioning via `emo_audio`, `emo_text`, or `emo_vector` passed in `extra_params`.
+2-stage TTS at 22.05 kHz. Requests use `ref_audio` for voice cloning, or an uploaded audio `voice` from `/v1/audio/voices`. IndexTTS-2.5 uses a multilingual tokenizer, CAMPPlus speaker projection, EnhancedCodec, and code-only Stage 0→1 transfer by default. Both versions support emotion conditioning via `emo_audio`, `emo_text`, or `emo_vector` passed in `extra_params`.
+
+### Prerequisites
+
+IndexTTS-2 uses its existing frontend and does not require the IndexTTS-2.5 text dependencies. Before launching IndexTTS-2.5, install its optional frontend dependencies:
+
+```bash
+pip install 'vllm-omni[indextts2]'
+```
 
 ### Launch
 ```bash
 vllm serve IndexTeam/IndexTTS-2 --omni --trust-remote-code --port 8092
 # or, to pass the bundled deploy config explicitly:
 bash examples/online_serving/text_to_speech/indextts2/run_server.sh
+
+# IndexTTS-2.5 default: use_gpt_latent=false
+MODEL_VERSION=2.5 \
+MODEL=/path/to/indextts-2.5 \
+bash examples/online_serving/text_to_speech/indextts2/run_server.sh
+
 ```
 
 ### Sending requests
@@ -161,14 +176,35 @@ python examples/online_serving/text_to_speech/indextts2/speech_client.py \
     --text "今天心情很好！" \
     --ref-audio /path/to/ref.wav \
     --emo-audio /path/to/happy.wav
+
+# IndexTTS-2.5 Japanese request
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+    --model-version 2.5 \
+    --model /path/to/indextts-2.5 \
+    --lang ja \
+    --text "こんにちは、音声合成のテストです。" \
+    --ref-audio /path/to/ref.wav
+
+# IndexTTS-2.5 native speed control
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+    --model-version 2.5 \
+    --model /path/to/indextts-2.5 \
+    --speed 2.0 \
+    --text "这是两倍速度的语音合成测试。" \
+    --ref-audio /path/to/ref.wav
 ```
 
 ### Notes
 - Output: 22.05 kHz mono WAV.
-- Provide `ref_audio` on the documented raw request path, or pass `voice` only when it names an uploaded audio voice; IndexTTS-2 does not provide a built-in text-only preset voice.
+- Provide `ref_audio` on the documented raw request path, or pass `voice` only when it names an uploaded audio voice; neither version provides a built-in text-only preset voice.
+- IndexTTS-2.5 request controls `lang` and `text_normalization` are carried in `extra_params`; the client does this for `--model-version 2.5`.
+- IndexTTS-2.5 accepts the public `speed` request field in `[0.5, 2.0]`: `2.0` generates shorter, faster speech and `0.5` generates longer, slower speech. This is native Stage 1 duration control, so serving does not apply the generic playback-speed adjustment a second time. IndexTTS-2 does not use this control.
+- IndexTTS-2.5 accepts language codes such as `zh`, `en`, `zhen` (mixed Chinese/English), `ja`, and `yue`. `Mandarin` is a vLLM-Omni convenience alias for `zh`. Japanese (`ja`) uses `fugashi` tokenization and produces audio, but it does not automatically expand numbers, dates, or percentages; callers should first write those inputs as readable Japanese text.
+- A request `seed` controls Stage 0 AR sampling and per-request CFM noise. Different concurrent batch compositions do not guarantee a bit-identical waveform.
+- IndexTTS-2.5 Stage 0 uses plain vLLM sampling and does not reproduce the official default `num_beams=3` beam search. For parity comparisons, run upstream with `num_beams=1`; output quality can differ from the official beam-search result.
 - Emotion params (`emo_audio`, `emo_text`, `emo_vector`, `emo_alpha`, `use_emo_text`, `use_random`) are passed via the `extra_params` field. Official precedence is `use_emo_text` > `emo_vector` > `emo_audio` > same emotion as the speaker reference.
-- `stream=true` is accepted as an OpenAI-compatible response path, but IndexTTS-2 is not async-chunk streaming; audio is produced after S2Mel receives the full mel-code sequence.
-- Deploy config: `vllm_omni/deploy/indextts2.yaml` (auto-loaded).
+- IndexTTS-2.5 uses `vllm_omni/deploy/indextts2_5.yaml` with the official code-only Stage 0 to Stage 1 contract.
+- For IndexTTS-2.5, set `MODEL` to the local native bundle; asset discovery accepts its nested `checkpoints/` layout.
 
 ---
 
diff --git a/examples/online_serving/text_to_speech/indextts2/run_server.sh b/examples/online_serving/text_to_speech/indextts2/run_server.sh
index 4a17b3b04..c904fb19f 100644
--- a/examples/online_serving/text_to_speech/indextts2/run_server.sh
+++ b/examples/online_serving/text_to_speech/indextts2/run_server.sh
@@ -1,20 +1,37 @@
 #!/bin/bash
-# Launch vLLM-Omni server for IndexTTS2
+# Launch vLLM-Omni server for IndexTTS 2.0 or 2.5.
 #
 # Usage from repository root:
 #   examples/online_serving/text_to_speech/indextts2/run_server.sh
-#   CUDA_VISIBLE_DEVICES=0 PORT=8092 MODEL=/path/to/IndexTeam/IndexTTS-2 examples/online_serving/text_to_speech/indextts2/run_server.sh
+#   MODEL_VERSION=2.5 MODEL=/path/to/native/bundle \
+#     examples/online_serving/text_to_speech/indextts2/run_server.sh
 
 set -e
 
 SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
 ROOT_DIR="$(cd -- "$SCRIPT_DIR/../../../.." && pwd)"
 
-MODEL="${MODEL:-IndexTeam/IndexTTS-2}"
+MODEL_VERSION="${MODEL_VERSION:-2.0}"
 PORT="${PORT:-8092}"
-DEPLOY_CONFIG="${DEPLOY_CONFIG:-$ROOT_DIR/vllm_omni/deploy/indextts2.yaml}"
 
-echo "Starting IndexTTS2 server with model: $MODEL"
+if [[ "$MODEL_VERSION" == "2.5" ]]; then
+    if [[ -z "${MODEL:-}" ]]; then
+        echo "Usage: MODEL_VERSION=2.5 MODEL=/path/to/native/bundle bash $0" >&2
+        exit 2
+    fi
+    DEFAULT_DEPLOY_CONFIG="$ROOT_DIR/vllm_omni/deploy/indextts2_5.yaml"
+elif [[ "$MODEL_VERSION" == "2.0" ]]; then
+    MODEL="${MODEL:-IndexTeam/IndexTTS-2}"
+    DEFAULT_DEPLOY_CONFIG="$ROOT_DIR/vllm_omni/deploy/indextts2.yaml"
+else
+    echo "MODEL_VERSION must be 2.0 or 2.5" >&2
+    exit 2
+fi
+
+DEPLOY_CONFIG="${DEPLOY_CONFIG:-$DEFAULT_DEPLOY_CONFIG}"
+
+echo "Starting IndexTTS $MODEL_VERSION server with model: $MODEL"
+echo "Deploy config: $DEPLOY_CONFIG"
 
 FLASHINFER_DISABLE_VERSION_CHECK=1 \
 vllm serve "$MODEL" \
diff --git a/examples/online_serving/text_to_speech/indextts2/speech_client.py b/examples/online_serving/text_to_speech/indextts2/speech_client.py
index b938f0bd3..65342a335 100644
--- a/examples/online_serving/text_to_speech/indextts2/speech_client.py
+++ b/examples/online_serving/text_to_speech/indextts2/speech_client.py
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-"""OpenAI-compatible client for IndexTTS2 TTS via /v1/audio/speech endpoint.
+"""OpenAI-compatible client for IndexTTS 2.0/2.5 via /v1/audio/speech.
 
 Examples:
     # With reference audio for voice cloning
@@ -54,13 +54,44 @@ def main() -> None:
     parser.add_argument("--emo-alpha", type=float, default=None, help="Emotion weight in [0, 1]")
     parser.add_argument("--use-emo-text", action="store_true", help="Infer emotion vector from emo-text or text")
     parser.add_argument("--use-random", action="store_true", help="Use random emotion prototypes")
-    parser.add_argument("--model", type=str, default="IndexTeam/IndexTTS-2")
+    parser.add_argument(
+        "--model-version",
+        choices=("2.0", "2.5"),
+        default="2.0",
+    )
+    parser.add_argument("--model", type=str, default=None)
+    parser.add_argument(
+        "--lang",
+        default="zh",
+        help=(
+            "IndexTTS 2.5 language code, for example zh/en/zhen/ja/yue; "
+            "zhen is mixed Chinese/English and Mandarin is a vLLM-Omni alias for zh"
+        ),
+    )
+    parser.add_argument(
+        "--no-text-normalization",
+        action="store_false",
+        dest="text_normalization",
+        help="Disable IndexTTS 2.5 text normalization",
+    )
+    parser.add_argument(
+        "--speed",
+        type=float,
+        default=1.0,
+        help="IndexTTS 2.5 native synthesis speed in [0.5, 2.0]; 2.0 is faster",
+    )
     parser.add_argument("--voice", type=str, default=None, help="Uploaded voice name to use instead of --ref-audio")
     parser.add_argument("--output", type=str, default="output.wav")
     parser.add_argument("--api-base", type=str, default=DEFAULT_API_BASE)
     parser.add_argument("--api-key", type=str, default=DEFAULT_API_KEY)
     parser.add_argument("--response-format", type=str, default="wav")
     args = parser.parse_args()
+    if args.model is None:
+        if args.model_version == "2.5":
+            parser.error("--model is required for IndexTTS 2.5")
+        args.model = "IndexTeam/IndexTTS-2"
+    if args.model_version == "2.5" and not 0.5 <= args.speed <= 2.0:
+        parser.error("IndexTTS 2.5 --speed must be between 0.5 and 2.0")
 
     if not args.ref_audio and not args.voice:
         parser.error("IndexTTS2 requires --ref-audio or --voice for voice cloning")
@@ -97,6 +128,10 @@ def main() -> None:
         extra_params["use_emo_text"] = True
     if args.use_random:
         extra_params["use_random"] = True
+    if args.model_version == "2.5":
+        payload["speed"] = args.speed
+        extra_params["lang"] = args.lang
+        extra_params["text_normalization"] = args.text_normalization
     if extra_params:
         payload["extra_params"] = extra_params
 
diff --git a/pyproject.toml b/pyproject.toml
index bbb8433f9..f9fbdfb2a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -84,6 +84,13 @@ forced-aligner = [
     "qwen-asr>=0.0.6",  # faithful Japanese/Korean word segmentation for the TTS forced aligner
 ]
 
+indextts2 = [
+    "fugashi>=1.2.0",
+    "unidic-lite>=1.0.0",
+    "wetext>=0.0.9; sys_platform != 'linux'",
+    "WeTextProcessing; sys_platform == 'linux'",
+]
+
 # Local-test-only extras
 local = [
     "FlagEmbedding",
@@ -327,3 +334,7 @@ byt5 = "byt5"
 # "seeked" is the standard HTML media element DOM event name (fires when a
 # seek completes), used by the word-timestamps Gradio demo. Not a typo.
 seeked = "seeked"
+# IndexTTS 2.5 language codes and speech-emotion-recognition event token.
+fo = "fo"
+ba = "ba"
+SER = "SER"
diff --git a/recipes/IndexTeam/IndexTTS-2_5.md b/recipes/IndexTeam/IndexTTS-2_5.md
new file mode 100644
index 000000000..b5b741c7e
--- /dev/null
+++ b/recipes/IndexTeam/IndexTTS-2_5.md
@@ -0,0 +1,308 @@
+# IndexTTS-2.5 for multilingual voice-cloned TTS on 1x GPU
+
+## Summary
+
+- Vendor: IndexTeam
+- Model: `IndexTeam/IndexTTS-2.5`
+- Task: Multilingual text-to-speech with voice cloning, emotion control, and
+  native speed control
+- Mode: Online serving with the OpenAI-compatible `/v1/audio/speech` API, or
+  offline inference through `Omni`
+- Maintainer: Community
+
+## When to use this recipe
+
+Use this recipe to serve IndexTTS-2.5 as a two-stage TTS system. Stage 0 is an
+autoregressive talker; Stage 1 uses EnhancedCodec, S2Mel CFM/DiT, and BigVGAN
+to produce 22.05 kHz mono speech. Each request supplies synthesis text and
+reference audio, or an uploaded audio voice, for zero-shot voice cloning.
+
+IndexTTS-2.5 adds multilingual text processing and model-native speed control
+to the IndexTTS-2 serving contract.
+
+## References
+
+- Upstream model:
+  [IndexTeam/IndexTTS-2.5 on Hugging Face](https://huggingface.co/IndexTeam/IndexTTS-2.5)
+- Online serving example:
+  [`examples/online_serving/text_to_speech/README.md#indextts-2-and-indextts-25`](../../examples/online_serving/text_to_speech/README.md#indextts-2-and-indextts-25)
+- Offline inference example:
+  [`examples/offline_inference/text_to_speech/README.md#indextts-2-and-indextts-25`](../../examples/offline_inference/text_to_speech/README.md#indextts-2-and-indextts-25)
+- OpenAI-compatible client:
+  [`examples/online_serving/text_to_speech/indextts2/speech_client.py`](../../examples/online_serving/text_to_speech/indextts2/speech_client.py)
+- Standard deploy config:
+  [`vllm_omni/deploy/indextts2_5.yaml`](../../vllm_omni/deploy/indextts2_5.yaml)
+
+## Hardware Support
+
+### GPU
+
+### 1x NVIDIA H20 96GB
+
+#### Environment
+
+- OS: Linux
+- Python: 3.10+
+- Driver / runtime: NVIDIA CUDA environment
+- vLLM version: Match the repository requirements for your checkout
+- vLLM-Omni version or commit: Use the commit you are deploying from
+
+Install vLLM-Omni with the IndexTTS text-processing dependencies:
+
+```bash
+pip install 'vllm-omni[indextts2]'
+```
+
+Obtain the native IndexTTS-2.5 bundle and point `MODEL` at its root. The model
+loader accepts the upstream nested `checkpoints/` layout.
+
+#### Command
+
+Start the standard code-only server from the repository root:
+
+```bash
+MODEL_VERSION=2.5 \
+MODEL=/path/to/indextts-2.5 \
+bash examples/online_serving/text_to_speech/indextts2/run_server.sh
+```
+
+This selects `vllm_omni/deploy/indextts2_5.yaml`, which uses
+`use_gpt_latent=false`. To launch directly:
+
+```bash
+vllm serve /path/to/indextts-2.5 \
+  --omni \
+  --trust-remote-code \
+  --port 8092 \
+  --deploy-config vllm_omni/deploy/indextts2_5.yaml
+```
+
+#### Optional: NVIDIA MPS for higher single-GPU throughput
+
+Stage 0 and Stage 1 run in separate processes on the same GPU. Enabling
+NVIDIA Multi-Process Service (MPS) can improve steady-state throughput by
+allowing work from both stages to overlap more effectively. MPS is an opt-in
+deployment optimization: this recipe does not start it automatically, and the
+gain depends on the request mix and concurrency, so benchmark it with the
+intended workload before enabling it in production.
+
+Pay attention to CUDA device renumbering. For example, if the MPS control
+daemon is started with physical `CUDA_VISIBLE_DEVICES=1`, that GPU is exposed
+to MPS clients as logical device `0`; launch the server with
+`CUDA_VISIBLE_DEVICES=0`, not `1`. Use a dedicated MPS pipe/log directory when
+the host is shared with other services, and stop only the MPS daemon owned by
+this deployment.
+
+#### Verification
+
+Send a multilingual voice-cloning request with the bundled client. Local audio
+paths are converted to base64 data URLs before transmission:
+
+```bash
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --api-base http://localhost:8092 \
+  --model-version 2.5 \
+  --model /path/to/indextts-2.5 \
+  --lang zh \
+  --text "你好，这是 IndexTTS-2.5 语音合成测试。" \
+  --ref-audio /path/to/reference.wav \
+  --output indextts2_5.wav
+```
+
+##### Native speed control
+
+The public `speed` field is handled natively. Its accepted range is
+`[0.5, 2.0]`; values above `1.0` produce shorter, faster speech. The serving
+adapter converts the API convention to the model-native control with
+`duration_factor = 1.0 / speed`, so `speed=1.25` uses
+`duration_factor=0.8`:
+
+```bash
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --api-base http://localhost:8092 \
+  --model-version 2.5 \
+  --model /path/to/indextts-2.5 \
+  --speed 1.25 \
+  --text "这是使用模型原生语速控制的测试。" \
+  --ref-audio /path/to/reference.wav \
+  --output indextts2_5_speed.wav
+```
+
+##### Upload and reuse a named voice
+
+Upload a reference recording once when callers should reuse the same voice
+without sending `ref_audio` on every request. `consent` is required by the
+voice-storage API:
+
+```bash
+curl -X POST http://localhost:8092/v1/audio/voices \
+  -F "audio_sample=@/path/to/reference.wav" \
+  -F "consent=user-consent-id" \
+  -F "name=indextts_demo_voice" \
+  -F "speaker_description=IndexTTS-2.5 demonstration voice"
+```
+
+Confirm that the voice was stored, then synthesize with its name instead of a
+reference-audio payload:
+
+```bash
+curl http://localhost:8092/v1/audio/voices
+
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --api-base http://localhost:8092 \
+  --model-version 2.5 \
+  --model /path/to/indextts-2.5 \
+  --voice indextts_demo_voice \
+  --lang zh \
+  --text "你好，这是复用已上传音色的语音合成测试。" \
+  --output indextts2_5_named_voice.wav
+```
+
+There are no built-in text-only preset voices. Each named IndexTTS voice must
+first be created from an uploaded reference recording.
+
+##### Multilingual synthesis and text normalization
+
+The client accepts `zh` (Mandarin), `en` (English), `zhen` (mixed Chinese and
+English), `ja` (Japanese), and `yue` (Cantonese). The following commands use
+the same reference voice across all supported language modes:
+
+```bash
+CLIENT=examples/online_serving/text_to_speech/indextts2/speech_client.py
+MODEL=/path/to/indextts-2.5
+REF_AUDIO=/path/to/reference.wav
+
+python "$CLIENT" --model-version 2.5 --model "$MODEL" \
+  --ref-audio "$REF_AUDIO" --lang zh \
+  --text "你好，这是中文语音合成测试。" --output indextts2_5_zh.wav
+
+python "$CLIENT" --model-version 2.5 --model "$MODEL" \
+  --ref-audio "$REF_AUDIO" --lang en \
+  --text "Hello, this is an English speech synthesis test." \
+  --output indextts2_5_en.wav
+
+python "$CLIENT" --model-version 2.5 --model "$MODEL" \
+  --ref-audio "$REF_AUDIO" --lang zhen \
+  --text "Hello，欢迎使用 IndexTTS 二点五。" --output indextts2_5_zhen.wav
+
+python "$CLIENT" --model-version 2.5 --model "$MODEL" \
+  --ref-audio "$REF_AUDIO" --lang ja \
+  --text "こんにちは、これは日本語の音声合成テストです。" \
+  --output indextts2_5_ja.wav
+
+python "$CLIENT" --model-version 2.5 --model "$MODEL" \
+  --ref-audio "$REF_AUDIO" --lang yue \
+  --text "你好，呢段係粵語語音合成測試。" --output indextts2_5_yue.wav
+```
+
+Text normalization is enabled by default. Disable it only when the input is
+already written exactly as it should be spoken:
+
+```bash
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --model-version 2.5 --model /path/to/indextts-2.5 \
+  --ref-audio /path/to/reference.wav --lang en --no-text-normalization \
+  --text "The temperature is twenty five degrees." \
+  --output indextts2_5_pre_normalized.wav
+```
+
+For raw HTTP requests, put the same language and text-normalization controls
+under `extra_params`:
+
+```bash
+curl http://localhost:8092/v1/audio/speech \
+  -H "Content-Type: application/json" \
+  -d '{
+    "model": "/path/to/indextts-2.5",
+    "input": "This is an IndexTTS-2.5 test.",
+    "response_format": "wav",
+    "speed": 1.0,
+    "ref_audio": "data:audio/wav;base64,<BASE64_ENCODED_AUDIO>",
+    "extra_params": {
+      "lang": "en",
+      "text_normalization": true
+    }
+  }' \
+  --output indextts2_5_en.wav
+```
+
+##### Emotion control
+
+IndexTTS-2.5 supports an explicit eight-value emotion vector, an emotion text
+description, or a separate emotion-reference recording. Use one source at a
+time. Vector values are ordered as `happy`, `angry`, `sad`, `afraid`,
+`disgusted`, `melancholic`, `surprised`, and `calm`; each value must be in
+`[0, 1.2]`. `emo_alpha` controls the strength in `[0, 1]`.
+
+Use an explicit emotion vector for deterministic control:
+
+```bash
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --model-version 2.5 --model /path/to/indextts-2.5 \
+  --ref-audio /path/to/reference.wav --lang zh \
+  --text "今天真是令人开心的一天！" \
+  --emo-vector 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 \
+  --emo-alpha 0.8 --output indextts2_5_happy_vector.wav
+```
+
+Infer the emotion from a natural-language description with `use_emo_text`:
+
+```bash
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --model-version 2.5 --model /path/to/indextts-2.5 \
+  --ref-audio /path/to/reference.wav --lang zh \
+  --text "我们终于完成了这项工作！" \
+  --use-emo-text --emo-text "开心、兴奋而且充满活力" \
+  --emo-alpha 0.8 --output indextts2_5_happy_text.wav
+```
+
+Transfer emotion from a recording while retaining the speaker identity from
+`ref_audio`:
+
+```bash
+python examples/online_serving/text_to_speech/indextts2/speech_client.py \
+  --model-version 2.5 --model /path/to/indextts-2.5 \
+  --ref-audio /path/to/reference.wav --lang zh \
+  --text "请用情绪参考音频中的表达方式朗读这句话。" \
+  --emo-audio /path/to/emotion_reference.wav \
+  --emo-alpha 0.8 --output indextts2_5_emotion_audio.wav
+```
+
+If multiple emotion sources are supplied, the official precedence is
+`use_emo_text` > `emo_vector` > `emo_audio` > the emotion in the speaker
+reference. `--use-random` is also available for exploratory random emotion
+prototypes, but should not be used when reproducible conditioning is required.
+
+For offline inference:
+
+```bash
+python examples/offline_inference/text_to_speech/indextts2/end2end.py \
+  --model /path/to/indextts-2.5 \
+  --model-version 2.5 \
+  --lang zh \
+  --speed 1.0 \
+  --text "你好，这是离线语音合成测试。" \
+  --ref-audio /path/to/reference.wav
+```
+
+#### Notes
+
+- Hardware scope: the standard recipe has been exercised on one NVIDIA H200.
+  It does not claim an unverified throughput or quality result.
+- Audio output: 22.05 kHz mono WAV.
+- Voice cloning: reference audio is required on the documented raw request
+  path. Alternatively, `voice` may name an uploaded audio voice; there is no
+  built-in text-only preset voice.
+- Native speed: serving maps `speed` to the model's duration factor and skips
+  generic waveform speed adjustment, so speed is applied exactly once.
+- Languages: common codes include `zh`, `en`, `zhen` (mixed Chinese/English),
+  `ja`, and `yue`; `Mandarin` is accepted as an alias for `zh`.
+- Japanese normalization: `ja` tokenization does not automatically expand
+  numbers, dates, or percentages. Write these inputs as readable Japanese text
+  before inference.
+- Emotion controls: `use_emo_text`, `emo_vector`, and `emo_audio` are
+  alternative conditioning modes. Their precedence is `use_emo_text` >
+  `emo_vector` > `emo_audio` > the speaker-reference emotion.
+- Sampling difference: Stage 0 uses plain vLLM sampling, not the upstream
+  default `num_beams=3` beam search. Use upstream `num_beams=1` for parity
+  comparisons; output may differ from the official beam-search result.
diff --git a/recipes/README.md b/recipes/README.md
index eb4016482..ca287bf70 100644
--- a/recipes/README.md
+++ b/recipes/README.md
@@ -50,6 +50,7 @@ recipes/
 | [`inclusionAI/Ming-flash-omni-2.0.md`](./inclusionAI/Ming-flash-omni-2.0.md) | Online serving for multimodal chat + standalone TTS | 4x H100 / 1x H100 80GB |
 | [`inclusionAI/Ming-omni-tts.md`](./inclusionAI/Ming-omni-tts.md) | Offline + online dense Ming TTS/audio generation | 1x H100 80GB / 1x AMD MI300X (ROCm 7.2) |
 | [`IndexTeam/IndexTTS-2.md`](./IndexTeam/IndexTTS-2.md) | Online serving for voice-cloned TTS with optional emotion control | 1x L4 24GB or larger CUDA GPU |
+| [`IndexTeam/IndexTTS-2_5.md`](./IndexTeam/IndexTTS-2_5.md) | Online + offline multilingual voice-cloned TTS with native speed and emotion control | 1x NVIDIA H20 96GB |
 | [`MiniMaxAI/MiniMax-H3.md`](./MiniMaxAI/MiniMax-H3.md) | T2VA, FL2VA, image+audio Ref2VA, and multi-video Ref2VA serving | 1x GPU with CPU offload / 4x B300 |
 | [`MiniMaxAI/MiniMax-H3-MUSA.md`](./MiniMaxAI/MiniMax-H3-MUSA.md) | MiniMax H3 T2VA, FL2VA, and Ref2VA on MUSA | 4x MTT S5000 (TP4 Ref2VA profile) |
 | [`krea/Krea-2.md`](./krea/Krea-2.md) | Text-to-image (Turbo + Raw), offline + online, with LoRA | 1x H100 80GB |
diff --git a/tests/benchmarks/test_bench_tts_cli.py b/tests/benchmarks/test_bench_tts_cli.py
index b8a487f80..e32d94698 100644
--- a/tests/benchmarks/test_bench_tts_cli.py
+++ b/tests/benchmarks/test_bench_tts_cli.py
@@ -51,6 +51,14 @@ def test_load_model_configs(model_configs_path: Path) -> None:
     assert configs["test/ModelA"]["supported_tasks"] == ["voice_clone", "default_voice"]
 
 
+def test_indextts25_is_registered_in_shared_model_configs() -> None:
+    config_path = Path(bench_tts.__file__).with_name("model_configs.yaml")
+    config = bench_tts.load_model_configs(config_path)["IndexTeam/IndexTTS-2.5"]
+
+    assert config["supported_tasks"] == ["voice_clone"]
+    assert config["task_extra_body"]["voice_clone"]["extra_params"]["lang"] == "en"
+
+
 def test_build_bench_args_voice_clone(model_configs_path: Path) -> None:
     configs = bench_tts.load_model_configs(model_configs_path)
     cmd = bench_tts.build_bench_args(
@@ -120,6 +128,34 @@ def test_build_bench_args_wer_eval_adds_flag(model_configs_path: Path) -> None:
     assert "--seed-tts-wer-eval" in cmd
 
 
+def test_build_bench_args_supports_local_model_and_shared_sweep_options(model_configs_path: Path) -> None:
+    configs = bench_tts.load_model_configs(model_configs_path)
+    cmd = bench_tts.build_bench_args(
+        host="localhost",
+        port=8092,
+        model="test/ModelA",
+        served_model_name="/models/indextts25",
+        task="voice_clone",
+        model_cfg=configs["test/ModelA"],
+        locale="en",
+        num_prompts=500,
+        num_warmups=5,
+        request_seed=42,
+        concurrency=8,
+        dataset_path="/data/seed-tts",
+        wer_eval=False,
+        output_dir=None,
+        result_filename=None,
+        extra_cli_args=["--", "--tokenizer", "/models/indextts25/qwen0.6bemo4-merge"],
+    )
+
+    assert cmd[cmd.index("--model") + 1] == "/models/indextts25"
+    assert cmd[cmd.index("--num-warmups") + 1] == "5"
+    assert cmd[-2:] == ["--tokenizer", "/models/indextts25/qwen0.6bemo4-merge"]
+    extra_body = json.loads(cmd[cmd.index("--extra-body") + 1])
+    assert extra_body == {"task_type": "Base", "seed": 42}
+
+
 def test_unsupported_task_exits(model_configs_path: Path, capsys: pytest.CaptureFixture, mocker) -> None:
     # ModelB does not support voice_design
     mocker.patch.object(
diff --git a/tests/config/test_config_factory.py b/tests/config/test_config_factory.py
index eb774bb18..c3c3edbd1 100644
--- a/tests/config/test_config_factory.py
+++ b/tests/config/test_config_factory.py
@@ -2276,6 +2276,16 @@ class TestPlatformOverrides:
         # Stage 2 unaffected fields stay at base
         assert deploy.stages[2].enforce_eager is False
 
+    def test_qwen2_5_omni_xpu_uses_eager_ar_stages(self):
+        deploy_path = Path(get_deploy_config_path("qwen2_5_omni.yaml"))
+
+        deploy = load_deploy_config(deploy_path)
+        deploy = _apply_platform_overrides(deploy, platform="xpu")
+
+        assert deploy.stages[0].enforce_eager is True
+        assert deploy.stages[1].enforce_eager is True
+        assert deploy.stages[2].enforce_eager is True
+
     def test_xpu_overrides(self):
         deploy_path = Path(get_deploy_config_path("qwen3_omni_moe.yaml"))
         if not deploy_path.exists():
diff --git a/tests/core/sched/test_omni_scheduling_coordinator.py b/tests/core/sched/test_omni_scheduling_coordinator.py
index a36a94e7d..a93929306 100644
--- a/tests/core/sched/test_omni_scheduling_coordinator.py
+++ b/tests/core/sched/test_omni_scheduling_coordinator.py
@@ -126,6 +126,7 @@ class TestFullPayloadCoordinatorSelection(unittest.TestCase):
             ("AudexCode2Wav", "audex_code2wav"),
             ("AudexXCodec1", "audex_xcodec"),
             ("IndexTTS2S2MelDecoder", "indextts2_s2mel_decoder"),
+            ("IndexTTS25S2MelDecoder", "indextts2_5_s2mel_decoder"),
             ("DyninOmniForConditionalGeneration", "token2image"),
             ("DyninOmniForConditionalGeneration", "token2audio"),
         }
diff --git a/tests/engine/test_arg_utils.py b/tests/engine/test_arg_utils.py
index 2e2f75194..055866bd5 100644
--- a/tests/engine/test_arg_utils.py
+++ b/tests/engine/test_arg_utils.py
@@ -6,6 +6,9 @@ explicitly patch values that differ from vLLM.
 
 import argparse
 import inspect
+import json
+import os
+import shutil
 from types import SimpleNamespace
 from unittest.mock import Mock
 
@@ -194,6 +197,155 @@ def test_qwen3_tts_code2wav_injects_max_position_embeddings(monkeypatch):
     }
 
 
+def test_patch_missing_local_hf_config(tmp_path):
+    """Native model bundles may only contain a checkpoints/ directory."""
+    (tmp_path / "checkpoints").mkdir()
+    args = object.__new__(OmniEngineArgs)
+    args.model = str(tmp_path)
+    args.model_arch = "IndexTTS25TalkerForConditionalGeneration"
+    args.hf_config_path = None
+
+    try:
+        args._patch_empty_hf_config("indextts2_5")
+
+        assert args.hf_config_path is not None
+        config_path = args.hf_config_path + "/config.json"
+        with open(config_path, encoding="utf-8") as config_file:
+            config = json.load(config_file)
+        assert config == {
+            "model_type": "indextts2_5",
+            "architectures": ["IndexTTS25TalkerForConditionalGeneration"],
+        }
+    finally:
+        if hasattr(args, "_temp_config_dir"):
+            shutil.rmtree(args._temp_config_dir, ignore_errors=True)
+
+
+@pytest.mark.parametrize(
+    "config_entry",
+    ["malformed", "directory", "broken_symlink", "permission_error"],
+)
+def test_non_missing_local_hf_config_error_reaches_parent_loader(tmp_path, monkeypatch, config_entry):
+    """Non-missing config errors must reach vLLM's normal loader."""
+    config_path = tmp_path / "config.json"
+    if config_entry == "malformed":
+        config_path.write_text("{not valid json", encoding="utf-8")
+        loader_error = json.JSONDecodeError("invalid config", "{not valid json", 1)
+    elif config_entry == "directory":
+        config_path.mkdir()
+        loader_error = IsADirectoryError(str(config_path))
+    elif config_entry == "broken_symlink":
+        config_path.symlink_to(tmp_path / "missing-target.json")
+        loader_error = FileNotFoundError(str(config_path))
+    else:
+        config_path.write_text("{}", encoding="utf-8")
+        loader_error = PermissionError(str(config_path))
+
+    parent_inputs = {}
+
+    def controlled_get_config_dict(cls, model, **kwargs):
+        if model == str(tmp_path):
+            raise loader_error
+        with open(os.path.join(model, "config.json"), encoding="utf-8") as config_file:
+            return json.load(config_file), {}
+
+    def fake_parent_create_model_config(self):
+        parent_inputs["called"] = True
+        parent_inputs["model"] = self.model
+        parent_inputs["hf_config_path"] = self.hf_config_path
+        config_root = self.hf_config_path or self.model
+        parent_inputs["config_root"] = config_root
+        return PretrainedConfig.get_config_dict(config_root)[0]
+
+    monkeypatch.setattr(PretrainedConfig, "get_config_dict", classmethod(controlled_get_config_dict))
+    monkeypatch.setattr(OmniEngineArgs, "_ensure_omni_models_registered", lambda self: True)
+    monkeypatch.setattr(EngineArgs, "create_model_config", fake_parent_create_model_config)
+    monkeypatch.setattr(
+        OmniModelConfig,
+        "from_vllm_model_config",
+        classmethod(lambda cls, model_config, **omni_kwargs: model_config),
+    )
+
+    args = OmniEngineArgs(
+        model=str(tmp_path),
+        model_arch="IndexTTS25TalkerForConditionalGeneration",
+    )
+
+    with pytest.raises(type(loader_error)) as exc_info:
+        args.create_model_config()
+
+    assert str(exc_info.value) == str(loader_error)
+    assert parent_inputs["called"] is True
+    assert parent_inputs["model"] == str(tmp_path)
+    assert parent_inputs["config_root"] == str(tmp_path)
+    assert parent_inputs["hf_config_path"] is None
+    assert args.model == str(tmp_path)
+    assert args.hf_config_path is None
+    assert not hasattr(args, "_temp_config_dir")
+
+
+def test_patch_valid_hf_config_without_model_type_preserves_keys(tmp_path):
+    """A valid partial config should be copied before required keys are added."""
+    original_config = {
+        "hidden_size": 1024,
+        "custom_key": {"nested": True},
+    }
+    (tmp_path / "config.json").write_text(json.dumps(original_config), encoding="utf-8")
+    args = object.__new__(OmniEngineArgs)
+    args.model = str(tmp_path)
+    args.model_arch = "IndexTTS25TalkerForConditionalGeneration"
+    args.hf_config_path = None
+
+    try:
+        args._patch_empty_hf_config("indextts2_5")
+
+        assert args.hf_config_path is not None
+        with open(os.path.join(args.hf_config_path, "config.json"), encoding="utf-8") as config_file:
+            patched_config = json.load(config_file)
+        assert patched_config["hidden_size"] == original_config["hidden_size"]
+        assert patched_config["custom_key"] == original_config["custom_key"]
+        assert patched_config["model_type"] == "indextts2_5"
+        assert patched_config["architectures"] == ["IndexTTS25TalkerForConditionalGeneration"]
+    finally:
+        if hasattr(args, "_temp_config_dir"):
+            shutil.rmtree(args._temp_config_dir, ignore_errors=True)
+
+
+def test_remote_hf_config_error_reaches_parent_loader(monkeypatch):
+    """Remote resolution failures must stay on vLLM's normal error path."""
+    loader_error = OSError("remote config resolution failed")
+    parent_inputs = {}
+
+    def controlled_get_config_dict(cls, model, **kwargs):
+        raise loader_error
+
+    def fake_parent_create_model_config(self):
+        parent_inputs["called"] = True
+        parent_inputs["model"] = self.model
+        parent_inputs["hf_config_path"] = self.hf_config_path
+        return PretrainedConfig.get_config_dict(self.model)[0]
+
+    monkeypatch.setattr(PretrainedConfig, "get_config_dict", classmethod(controlled_get_config_dict))
+    monkeypatch.setattr(OmniEngineArgs, "_ensure_omni_models_registered", lambda self: True)
+    monkeypatch.setattr(EngineArgs, "create_model_config", fake_parent_create_model_config)
+
+    args = OmniEngineArgs(
+        model="remote/model",
+        model_arch="IndexTTS25TalkerForConditionalGeneration",
+    )
+
+    with pytest.raises(OSError) as exc_info:
+        args.create_model_config()
+
+    assert str(exc_info.value) == str(loader_error)
+    assert parent_inputs["called"] is True
+    assert parent_inputs["model"] == "remote/model"
+    assert parent_inputs["hf_config_path"] is None
+    assert args.model == "remote/model"
+    assert args.hf_config_path is None
+    assert not hasattr(args, "_temp_config_dir")
+
+
 def test_stage_specific_text_config_override():
     """Stage swap must refresh hf_text_config, dependent attrs, and model_arch_config."""
     vllm_config = EngineArgs().create_model_config()
diff --git a/tests/engine/test_async_omni_engine_stage_init.py b/tests/engine/test_async_omni_engine_stage_init.py
index 67765aba6..27aee8706 100644
--- a/tests/engine/test_async_omni_engine_stage_init.py
+++ b/tests/engine/test_async_omni_engine_stage_init.py
@@ -412,7 +412,7 @@ def test_stage_runtime_passes_log_stats_to_llm_replica_launch(monkeypatch):
     monkeypatch.setattr(
         runtime_mod.StageEngineCoreClientBase,
         "make_async_mp_client",
-        lambda **kwargs: (captured.__setitem__("client_log_stats", kwargs["log_stats"]) or stage_client),
+        lambda **kwargs: captured.__setitem__("client_log_stats", kwargs["log_stats"]) or stage_client,
     )
 
     assert runtime._initialize_local_llm_replica(plan, stage_init_timeout=1) is stage_client
@@ -807,9 +807,9 @@ def test_build_stage0_input_processor_uses_omni_input_preprocessor(monkeypatch):
     import vllm_omni.engine.stage_init_utils as init_mod
 
     class DummyInputProcessor:
-        def __init__(self, vllm_config):
+        def __init__(self, vllm_config, renderer=None):
             self.vllm_config = vllm_config
-            self.renderer = object()
+            self.renderer = renderer or object()
             self.input_preprocessor = None
 
     class DummyOmniInputPreprocessor:
@@ -828,6 +828,50 @@ def test_build_stage0_input_processor_uses_omni_input_preprocessor(monkeypatch):
     assert input_processor.input_preprocessor.renderer is input_processor.renderer
 
 
+def test_build_stage0_input_processor_does_not_resolve_tokenizer_when_skipped(
+    monkeypatch,
+):
+    import vllm_omni.engine.stage_init_utils as init_mod
+
+    token_only_renderer = object()
+    seen = {}
+
+    class DummyInputProcessor:
+        def __init__(self, vllm_config, renderer=None):
+            if renderer is None:
+                raise AssertionError("skip_tokenizer_init must supply a renderer")
+            seen["renderer"] = renderer
+            self.renderer = renderer
+            self.input_preprocessor = None
+
+    class DummyOmniInputPreprocessor:
+        def __init__(self, vllm_config, renderer=None):
+            seen["preprocessor_renderer"] = renderer
+
+    monkeypatch.setattr(init_mod, "InputProcessor", DummyInputProcessor)
+    monkeypatch.setattr(
+        init_mod,
+        "_build_token_only_renderer",
+        lambda _config: token_only_renderer,
+    )
+    monkeypatch.setattr(
+        init_mod,
+        "OmniInputPreprocessor",
+        DummyOmniInputPreprocessor,
+    )
+
+    config = types.SimpleNamespace(
+        model_config=types.SimpleNamespace(
+            skip_tokenizer_init=True,
+            try_get_generation_config=lambda: {},
+        )
+    )
+    build_stage0_input_processor(config)
+
+    assert seen["renderer"] is token_only_renderer
+    assert seen["preprocessor_renderer"] is token_only_renderer
+
+
 def test_inject_kv_stage_info_infers_sender_tp_topology():
     from vllm_omni.engine.stage_init_utils import inject_kv_stage_info
 
diff --git a/tests/engine/test_omni_request.py b/tests/engine/test_omni_request.py
index 4f4718f09..521c92b94 100644
--- a/tests/engine/test_omni_request.py
+++ b/tests/engine/test_omni_request.py
@@ -52,6 +52,7 @@ def test_positional_construction_matches_base_request():
     assert req.external_req_id is None
     assert req.additional_information is None
     assert req.prompt_embeds_payload is None
+    assert req.num_stale_output_tokens == 0
 
 
 def test_positional_prompt_embeds_does_not_collide():
diff --git a/tests/entrypoints/openai_api/test_serving_speech.py b/tests/entrypoints/openai_api/test_serving_speech.py
index e1efd9286..32de8ac62 100644
--- a/tests/entrypoints/openai_api/test_serving_speech.py
+++ b/tests/entrypoints/openai_api/test_serving_speech.py
@@ -743,6 +743,48 @@ class TestTTSMethods:
         assert speech_server._is_tts is False
         assert speech_server._tts_stage is None
 
+    @pytest.mark.parametrize(
+        ("model_type", "expected_speed"),
+        [("indextts2_5", 1.0), ("qwen3_tts", 2.0)],
+    )
+    def test_audio_encode_speed_respects_adapter_native_control(
+        self,
+        speech_server,
+        model_type,
+        expected_speed,
+    ):
+        speech_server._tts_model_type = model_type
+        request = OpenAICreateSpeechRequest(input="Hello", speed=2.0)
+
+        assert speech_server._audio_encode_speed(request) == expected_speed
+
+    @pytest.mark.asyncio
+    async def test_non_streaming_native_speed_skips_generic_audio_adjustment(
+        self,
+        speech_server,
+        mocker: MockerFixture,
+    ):
+        async def mock_generate():
+            yield create_mock_audio_output_for_test()
+
+        speech_server._tts_model_type = "indextts2_5"
+        mocker.patch.object(
+            speech_server,
+            "_prepare_speech_generation",
+            new=mocker.AsyncMock(return_value=("speech-native-speed", mock_generate(), {})),
+        )
+        create_audio = mocker.patch.object(
+            speech_server,
+            "create_audio",
+            return_value=SimpleNamespace(audio_data=b"dummy", media_type="audio/wav"),
+        )
+
+        await speech_server._generate_audio_bytes(OpenAICreateSpeechRequest(input="Hello", speed=2.0))
+
+        audio_obj = create_audio.call_args.args[0]
+        assert isinstance(audio_obj, CreateAudio)
+        assert audio_obj.speed == 1.0
+
     def test_is_tts_detection_with_tts_stage(self, mocker: MockerFixture):
         """Test TTS model detection when TTS stage exists."""
         mock_engine_client = mocker.MagicMock()
@@ -2178,17 +2220,17 @@ class TestStreamingProtocolValidation:
         assert req.is_streaming() is False
 
     def test_stream_validation_errors(self):
-        """stream=True requires response_format in ('pcm', 'wav') and speed=1.0."""
+        """The request schema validates formats; model-aware speed checks happen in serving."""
         with pytest.raises(ValidationError, match="requires response_format='pcm' or 'wav'"):
             OpenAICreateSpeechRequest(input="Hello", stream=True, response_format="mp3")
-        with pytest.raises(ValidationError, match="Speed adjustment is not supported"):
-            OpenAICreateSpeechRequest(input="Hello", stream=True, response_format="pcm", speed=2.0)
+        request = OpenAICreateSpeechRequest(input="Hello", stream=True, response_format="pcm", speed=2.0)
+        assert request.speed == 2.0
 
     def test_stream_format_audio_validation_errors(self):
         with pytest.raises(ValidationError, match="requires response_format='pcm' or 'wav'"):
             OpenAICreateSpeechRequest(input="Hello", stream_format="audio", response_format="mp3")
-        with pytest.raises(ValidationError, match="Speed adjustment is not supported"):
-            OpenAICreateSpeechRequest(input="Hello", stream_format="audio", response_format="pcm", speed=2.0)
+        request = OpenAICreateSpeechRequest(input="Hello", stream_format="audio", response_format="pcm", speed=2.0)
+        assert request.speed == 2.0
 
     def test_stream_valid(self):
         """stream=True + response_format in ('pcm', 'wav') + speed=1.0 is accepted as SSE."""
@@ -2271,6 +2313,18 @@ class TestStreamingResponse:
             models=mock_models,
             request_logger=mocker.MagicMock(),
         )
+        speech_server._tts_model_type = None
+        speech_server._adapter = None
+        speech_server._diffusion_mode = False
+        mocker.patch.object(speech_server, "_uses_native_speed_control", return_value=False)
+        mocker.patch.object(
+            speech_server,
+            "create_error_response",
+            side_effect=lambda message, **_: JSONResponse(
+                status_code=400,
+                content={"error": {"message": message}},
+            ),
+        )
 
         original_create_speech = speech_server.create_speech
         sig = signature(original_create_speech)
@@ -2285,6 +2339,7 @@ class TestStreamingResponse:
 
         app = FastAPI()
         app.add_api_route("/v1/audio/speech", speech_server.create_speech, methods=["POST"], response_model=None)
+        app.state.speech_server = speech_server
         return app
 
     @staticmethod
@@ -2393,6 +2448,39 @@ class TestStreamingResponse:
         assert response.status_code in (400, 422)
         assert "audio/" not in response.headers.get("content-type", "")
 
+    @pytest.mark.parametrize("stream_format", ["sse", "audio"])
+    def test_native_speed_control_accepts_streaming_speed(
+        self,
+        streaming_app,
+        mocker: MockerFixture,
+        stream_format: str,
+    ):
+        speech_server = streaming_app.state.speech_server
+        speech_server._tts_model_type = "indextts2_5"
+        speech_server._uses_native_speed_control.return_value = True
+
+        async def prepare(request, request_id=None, **kwargs):
+            del kwargs
+            generator = speech_server.engine_client.generate(prompt={}, request_id=request_id)
+            return request_id, generator, {"duration_factor": [1.0 / request.speed]}
+
+        mocker.patch.object(speech_server, "_prepare_speech_generation", side_effect=prepare)
+
+        client = TestClient(streaming_app)
+        response = client.post(
+            "/v1/audio/speech",
+            json={
+                "input": "Hello",
+                "stream_format": stream_format,
+                "response_format": "pcm",
+                "speed": 2.0,
+            },
+        )
+
+        assert response.status_code == 200
+        expected_media_type = "text/event-stream" if stream_format == "sse" else "audio/pcm"
+        assert expected_media_type in response.headers["content-type"]
+
     @pytest.fixture
     def erroring_streaming_app(self, mocker: MockerFixture):
         """Test app whose mock engine raises mid-stream, to exercise the SSE error event."""
@@ -2616,6 +2704,18 @@ def test_streaming_speech_session_config_accepts_non_streaming_mode():
     assert config.non_streaming_mode is True
 
 
+def test_streaming_speech_session_config_scopes_native_speed_to_http():
+    with pytest.raises(
+        ValidationError,
+        match="native speed control is only available through HTTP streaming",
+    ):
+        StreamingSpeechSessionConfig(
+            stream_audio=True,
+            response_format="pcm",
+            speed=1.5,
+        )
+
+
 class TestAsyncOmniSupportedTasks:
     """Test that AsyncOmni reports correct supported tasks based on output modalities."""
 
diff --git a/tests/entrypoints/openai_api/test_tts_adapter.py b/tests/entrypoints/openai_api/test_tts_adapter.py
index 89106900b..9ab744c83 100644
--- a/tests/entrypoints/openai_api/test_tts_adapter.py
+++ b/tests/entrypoints/openai_api/test_tts_adapter.py
@@ -4,6 +4,9 @@
 Pure-Python registry/resolution logic; no model or GPU resources are loaded.
 """
 
+import asyncio
+from types import SimpleNamespace
+
 import pytest
 
 from vllm_omni.entrypoints.openai.tts_adapters import (
@@ -11,9 +14,19 @@ from vllm_omni.entrypoints.openai.tts_adapters import (
     ARTTSAdapter,
     DiffusionTTSAdapter,
     all_tts_model_types,
+    detect_tts_model_type,
     resolve_adapter,
 )
+from vllm_omni.entrypoints.openai.tts_adapters.indextts2 import (
+    IndexTTS2Adapter,
+    IndexTTS25Adapter,
+    indextts2_conditioning_cache_salt,
+)
 from vllm_omni.entrypoints.openai.tts_adapters.qwen3_tts import Qwen3TTSAdapter
+from vllm_omni.model_executor.models.indextts2 import prompt_utils
+from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+    INDEXTTS25_TOKENIZER_FILE,
+)
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
 
@@ -35,6 +48,8 @@ EXPECTED_MODEL_TYPES = {
     "higgs_audio_v3",
     "glm_tts",
     "step_audio2",
+    "indextts2",
+    "indextts2_5",
 }
 
 
@@ -84,6 +99,113 @@ def test_qwen3_tts_metadata():
     assert issubclass(Qwen3TTSAdapter, ARTTSAdapter)
 
 
+def test_indextts_adapters_are_versioned():
+    assert resolve_adapter("indextts2") is IndexTTS2Adapter
+    assert resolve_adapter("indextts2_5") is IndexTTS25Adapter
+    assert IndexTTS25Adapter.stage_keys == frozenset({"indextts2_5_talker"})
+    assert detect_tts_model_type("indextts2_5_talker", None) == "indextts2_5"
+
+
+def test_indextts25_validates_explicit_language():
+    adapter = IndexTTS25Adapter(type("Context", (), {"server": object()})())
+
+    assert adapter._validate_extra_params({"lang": "ja"}) is None
+    assert "Unsupported IndexTTS 2.5 language" in adapter._validate_extra_params({"lang": "xx-invalid"})
+
+
+def _indextts25_adapter_and_request(*, speed: float):
+    server = SimpleNamespace(
+        uploaded_speakers={},
+        _validate_ref_audio_format=lambda ref_audio: None,
+    )
+    adapter = IndexTTS25Adapter(SimpleNamespace(server=server))
+    request = SimpleNamespace(
+        input="hello",
+        voice="alloy",
+        ref_audio=object(),
+        max_new_tokens=None,
+        extra_params=None,
+        speed=speed,
+    )
+    return adapter, request
+
+
+def test_indextts25_uses_native_speed_control_duration_factor():
+    adapter, fast_request = _indextts25_adapter_and_request(speed=2.0)
+    _, slow_request = _indextts25_adapter_and_request(speed=0.5)
+
+    assert adapter.native_speed_control is True
+    assert adapter.validate(fast_request) is None
+    assert adapter.validate(slow_request) is None
+    assert asyncio.run(adapter._build_params(fast_request))["duration_factor"] == [0.5]
+    assert asyncio.run(adapter._build_params(slow_request))["duration_factor"] == [2.0]
+
+
+@pytest.mark.parametrize("speed", [0.49, 2.01])
+def test_indextts25_rejects_out_of_range_native_speed(speed):
+    adapter, request = _indextts25_adapter_and_request(speed=speed)
+
+    assert adapter.validate(request) == "IndexTTS 2.5 speed must be between 0.5 and 2.0"
+
+
+def test_indextts25_speed_does_not_change_conditioning_cache_salt():
+    adapter, fast_request = _indextts25_adapter_and_request(speed=2.0)
+    _, slow_request = _indextts25_adapter_and_request(speed=0.5)
+    slow_request.ref_audio = fast_request.ref_audio
+
+    fast_params = asyncio.run(adapter._build_params(fast_request))
+    slow_params = asyncio.run(adapter._build_params(slow_request))
+
+    assert indextts2_conditioning_cache_salt(
+        fast_request,
+        fast_params,
+    ) == indextts2_conditioning_cache_salt(slow_request, slow_params)
+
+
+@pytest.mark.parametrize(
+    ("hf_config", "expected_tokenizer_file"),
+    [
+        (SimpleNamespace(tokenizer_file="custom-tokenizer.tiktoken"), "custom-tokenizer.tiktoken"),
+        (SimpleNamespace(), INDEXTTS25_TOKENIZER_FILE),
+    ],
+)
+def test_indextts25_build_uses_configured_tokenizer_file(
+    monkeypatch,
+    hf_config,
+    expected_tokenizer_file,
+):
+    captured = {}
+
+    def fake_estimate(*args, **kwargs):
+        captured.update(kwargs)
+        return 4
+
+    async def fake_build_params(request):
+        return {"lang": ["en"], "text_normalization": [True]}
+
+    monkeypatch.setattr(
+        prompt_utils,
+        "estimate_indextts2_prefill_prompt_len",
+        fake_estimate,
+    )
+    server = SimpleNamespace(
+        engine_client=SimpleNamespace(
+            model_config=SimpleNamespace(
+                model="/model",
+                hf_config=hf_config,
+            )
+        )
+    )
+    adapter = IndexTTS25Adapter(SimpleNamespace(server=server))
+    monkeypatch.setattr(adapter, "_build_params", fake_build_params)
+    request = SimpleNamespace(input="hello", ref_audio=None)
+
+    prepared = asyncio.run(adapter.build(request, [], False))
+
+    assert prepared.prompt["prompt_token_ids"] == [1] * 4
+    assert captured["tokenizer_file"] == expected_tokenizer_file
+
+
 def test_diffusion_adapter_extra_body_params_fallback():
     class _DiffAdapter(DiffusionTTSAdapter):
         name = "diff_probe"
diff --git a/tests/entrypoints/openai_api/test_tts_detection.py b/tests/entrypoints/openai_api/test_tts_detection.py
index 27c6082c1..c63e5c8e4 100644
--- a/tests/entrypoints/openai_api/test_tts_detection.py
+++ b/tests/entrypoints/openai_api/test_tts_detection.py
@@ -149,6 +149,7 @@ _PIPELINE_STAGES = [
     "glm_tts_dit",
     "higgs_audio_v2",
     "higgs_audio_v3",
+    "indextts2_5_talker",
     "indextts2_s2mel_decoder",
     "indextts2_talker",
     "latent_generator",
@@ -213,18 +214,23 @@ _CLAIMED_ARCH_CASES = [
     ("fused_thinker_talker", "Qwen3TTSForConditionalGeneration"),
 ]
 
-_REACHABLE = list(itertools.product(_STAGES, _UNCLAIMED_ARCHS)) + _CLAIMED_ARCH_CASES
+# The frozen ladder can only be compared over stages it knew about. New
+# adapter-owned stages are covered by their adapter tests and by the registry
+# completeness checks below.
+_NEW_ADAPTER_STAGE_KEYS = all_tts_stage_keys() - _LEGACY_TTS_MODEL_STAGES
+_LEGACY_REACHABLE_STAGES = [stage for stage in _STAGES if stage not in _NEW_ADAPTER_STAGE_KEYS]
+_REACHABLE = list(itertools.product(_LEGACY_REACHABLE_STAGES, _UNCLAIMED_ARCHS)) + _CLAIMED_ARCH_CASES
 
 
 @pytest.mark.parametrize(("model_stage", "model_arch"), _REACHABLE)
 def test_detection_matches_legacy_ladder(model_stage, model_arch):
     """Registry detection is identical to the ladder it replaced.
 
-    Covers every ``model_stage`` any in-tree pipeline emits (``_PIPELINE_STAGES``,
-    plus negatives) against every architecture no adapter claims, and each
-    claimed architecture against the stage keys it really ships with. Pairing a
-    claimed architecture with an unrelated model's stage key is excluded because
-    no pipeline can produce it, and is covered separately by
+    Covers every stage the frozen ladder knew about, plus non-TTS pipeline
+    stages and negatives, against every architecture no adapter claims. New
+    adapter-owned stages are tested by their adapter suites. Pairing a claimed
+    architecture with an unrelated model's stage key is excluded because no
+    pipeline can produce it, and is covered separately by
     ``test_arch_matching_is_a_fallback_not_an_override``.
     """
     assert detect_tts_model_type(model_stage, model_arch) == _legacy_detect(model_stage, model_arch)
@@ -251,7 +257,7 @@ def test_arch_matching_is_a_fallback_not_an_override():
 
 def test_stage_keys_cover_legacy_stage_set():
     """No stage key was dropped when the module constants were deleted."""
-    assert all_tts_stage_keys() == frozenset(_LEGACY_TTS_MODEL_STAGES)
+    assert _LEGACY_TTS_MODEL_STAGES <= all_tts_stage_keys()
 
 
 def test_pipeline_stage_list_is_complete():
diff --git a/tests/examples/online_serving/test_indextts2_run_server.py b/tests/examples/online_serving/test_indextts2_run_server.py
new file mode 100644
index 000000000..021706a7b
--- /dev/null
+++ b/tests/examples/online_serving/test_indextts2_run_server.py
@@ -0,0 +1,108 @@
+import os
+import re
+import subprocess
+from pathlib import Path
+
+import pytest
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+ROOT = Path(__file__).resolve().parents[3]
+SCRIPT = ROOT / "examples/online_serving/text_to_speech/indextts2/run_server.sh"
+README = ROOT / "examples/online_serving/text_to_speech/README.md"
+MACHINE_SPECIFIC_HOME_PATH = re.compile(r"(?:/home|/Users)/[^/\s`]+/")
+
+
+def run_server(
+    tmp_path: Path,
+    *,
+    model_version: str | None = None,
+    model: str | None = None,
+) -> tuple[subprocess.CompletedProcess[str], Path]:
+    argv_file = tmp_path / "vllm.argv"
+    stub = tmp_path / "vllm"
+    stub.write_text(
+        '#!/bin/bash\nprintf "%s\\0" "$@" > "$VLLM_ARGV_FILE"\n',
+        encoding="utf-8",
+    )
+    stub.chmod(0o755)
+
+    env = os.environ.copy()
+    for name in ("MODEL_VERSION", "MODEL", "DEPLOY_CONFIG", "PORT"):
+        env.pop(name, None)
+    env["PATH"] = f"{tmp_path}{os.pathsep}{env['PATH']}"
+    env["VLLM_ARGV_FILE"] = str(argv_file)
+
+    if model_version is not None:
+        env["MODEL_VERSION"] = model_version
+    if model is not None:
+        env["MODEL"] = model
+    result = subprocess.run(
+        ["bash", str(SCRIPT)],
+        cwd=ROOT,
+        env=env,
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    return result, argv_file
+
+
+def read_argv(argv_file: Path) -> list[str]:
+    return argv_file.read_bytes().decode().rstrip("\0").split("\0")
+
+
+@pytest.mark.parametrize("model", [None, ""])
+def test_version_2_5_requires_model_before_invoking_vllm(
+    tmp_path: Path,
+    model: str | None,
+) -> None:
+    result, argv_file = run_server(tmp_path, model_version="2.5", model=model)
+
+    assert result.returncode == 2
+    assert "MODEL=/path/to/native/bundle" in result.stderr
+    assert not argv_file.exists()
+
+
+def test_version_2_5_selects_deploy_config(
+    tmp_path: Path,
+) -> None:
+    model = "/models/indextts-2.5"
+    result, argv_file = run_server(
+        tmp_path,
+        model_version="2.5",
+        model=model,
+    )
+
+    assert result.returncode == 0, result.stderr
+    argv = read_argv(argv_file)
+    assert argv[:2] == ["serve", model]
+    deploy_config_index = argv.index("--deploy-config") + 1
+    assert Path(argv[deploy_config_index]) == ROOT / "vllm_omni/deploy/indextts2_5.yaml"
+
+
+@pytest.mark.parametrize("model_version", [None, "2.0"])
+def test_default_and_version_2_0_use_huggingface_model(
+    tmp_path: Path,
+    model_version: str | None,
+) -> None:
+    result, argv_file = run_server(tmp_path, model_version=model_version)
+
+    assert result.returncode == 0, result.stderr
+    argv = read_argv(argv_file)
+    assert argv[:2] == ["serve", "IndexTeam/IndexTTS-2"]
+    deploy_config_index = argv.index("--deploy-config") + 1
+    assert Path(argv[deploy_config_index]) == ROOT / "vllm_omni/deploy/indextts2.yaml"
+
+
+def test_invalid_model_version_exits_before_invoking_vllm(tmp_path: Path) -> None:
+    result, argv_file = run_server(tmp_path, model_version="3.0")
+
+    assert result.returncode == 2
+    assert "MODEL_VERSION must be 2.0 or 2.5" in result.stderr
+    assert not argv_file.exists()
+
+
+@pytest.mark.parametrize("path", [SCRIPT, README])
+def test_public_example_does_not_contain_machine_specific_home_path(path: Path) -> None:
+    assert MACHINE_SPECIFIC_HOME_PATH.search(path.read_text(encoding="utf-8")) is None
diff --git a/tests/model_executor/models/indextts2/__init__.py b/tests/model_executor/models/indextts2/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/model_executor/models/indextts2/test_configuration_and_pipeline.py b/tests/model_executor/models/indextts2/test_configuration_and_pipeline.py
new file mode 100644
index 000000000..f01a725d2
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_configuration_and_pipeline.py
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from pathlib import Path
+
+import yaml
+
+from vllm_omni.config.pipeline_registry import OMNI_PIPELINES
+from vllm_omni.model_executor.models.indextts2.configuration_indextts2 import (
+    IndexTTS2Config,
+    IndexTTS25Config,
+)
+from vllm_omni.model_executor.models.indextts2.pipeline import INDEXTTS25_PIPELINE
+
+
+def test_indextts25_defaults_are_distinct_from_v2():
+    v2 = IndexTTS2Config()
+    v25 = IndexTTS25Config()
+
+    assert v2.model_type == "indextts2"
+    assert v2.gpt["number_text_tokens"] == 12000
+    assert v2.gpt["condition_num_latent"] == 32
+    assert v2.use_gpt_latent is True
+    assert v2.semantic_codec_type == "repcodec"
+    assert v2.vocab_size == v2.gpt["number_mel_codes"]
+
+    assert v25.model_type == "indextts2_5"
+    assert v25.gpt["number_text_tokens"] == 60509
+    assert v25.gpt["condition_num_latent"] == 32
+    assert v25.use_gpt_latent is False
+    assert v25.semantic_codec_type == "enhanced"
+    assert v25.semantic_codec_checkpoint == "codec.pth"
+    assert v25.tokenizer_file == "multilingual_zh_ja_yue_char_del.tiktoken"
+    assert v25.vocab_size == v25.gpt["number_mel_codes"]
+
+
+def test_indextts25_explicit_overrides_win_over_defaults():
+    config = IndexTTS25Config(
+        use_gpt_latent=True,
+        gpt={
+            "number_text_tokens": 70000,
+            "condition_num_latent": 2,
+        },
+        vocab_size=9000,
+    )
+
+    assert config.use_gpt_latent is True
+    assert config.gpt["number_text_tokens"] == 70000
+    assert config.gpt["condition_num_latent"] == 2
+    assert config.gpt["model_dim"] == config.hidden_size
+    assert config.vocab_size == 9000
+
+
+def test_indextts25_pipeline_is_registered_with_two_distinct_stages():
+    assert OMNI_PIPELINES["indextts2_5"] is INDEXTTS25_PIPELINE
+    assert INDEXTTS25_PIPELINE.default_deploy_config_name == "indextts2_5.yaml"
+    assert [stage.model_stage for stage in INDEXTTS25_PIPELINE.stages] == [
+        "indextts2_5_talker",
+        "indextts2_5_s2mel_decoder",
+    ]
+    assert [stage.model_arch for stage in INDEXTTS25_PIPELINE.stages] == [
+        None,
+        "IndexTTS25S2MelDecoder",
+    ]
+    assert all("tokenizer" not in stage.extras for stage in INDEXTTS25_PIPELINE.stages)
+
+
+def test_indextts25_default_deploy_selects_validated_triton_backend():
+    deploy_path = Path(__file__).parents[4] / "vllm_omni" / "deploy" / "indextts2_5.yaml"
+    config = yaml.safe_load(deploy_path.read_text(encoding="utf-8"))
+    stage0 = next(stage for stage in config["stages"] if stage["stage_id"] == 0)
+
+    assert stage0["attention_backend"] == "TRITON_ATTN"
+    assert stage0["enable_chunked_prefill"] is False
+
+
+def test_indextts25_deploy_configs_keep_latent_policy_in_sync():
+    deploy_dir = Path(__file__).parents[4] / "vllm_omni" / "deploy"
+    expected = {"indextts2_5.yaml": False}
+    for filename, use_gpt_latent in expected.items():
+        with open(deploy_dir / filename, encoding="utf-8") as deploy_file:
+            config = yaml.safe_load(deploy_file)
+        assert config["pipeline"] == "indextts2_5"
+        assert config["async_chunk"] is False
+        assert all("tokenizer" not in stage for stage in config["stages"])
+        assert [stage["hf_overrides"]["use_gpt_latent"] for stage in config["stages"]] == [
+            use_gpt_latent,
+            use_gpt_latent,
+        ]
diff --git a/tests/model_executor/models/indextts2/test_dit_cuda_graph.py b/tests/model_executor/models/indextts2/test_dit_cuda_graph.py
new file mode 100644
index 000000000..6bb476fb9
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_dit_cuda_graph.py
@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from types import SimpleNamespace
+
+import pytest
+
+from vllm_omni.model_executor.models.indextts2.dit_cuda_graph import (
+    CUDAGraphDiTRunner,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+class _CopySpy:
+    def __init__(self):
+        self.sources = []
+
+    def copy_(self, source):
+        self.sources.append(source)
+        return self
+
+
+class _GraphSpy:
+    def __init__(self):
+        self.replays = 0
+
+    def replay(self):
+        self.replays += 1
+
+
+def test_replay_only_updates_dynamic_inputs_and_reuses_static_output():
+    runner = CUDAGraphDiTRunner(transformer=object())
+    graph = _GraphSpy()
+    static_x = _CopySpy()
+    static_c = _CopySpy()
+    static_pos = _CopySpy()
+    static_mask = _CopySpy()
+    static_out = object()
+    entry = SimpleNamespace(
+        graph=graph,
+        static_x=static_x,
+        static_c=static_c,
+        static_pos=static_pos,
+        static_mask=static_mask,
+        static_out=static_out,
+    )
+    x_in = object()
+    c = object()
+
+    output = runner._replay(entry, x_in=x_in, c=c)
+
+    assert static_x.sources == [x_in]
+    assert static_c.sources == [c]
+    assert static_pos.sources == []
+    assert static_mask.sources == []
+    assert graph.replays == 1
+    assert output is static_out
+
+
+def test_graph_stats_start_empty_and_remain_bounded():
+    runner = CUDAGraphDiTRunner(transformer=object(), max_graphs=4)
+
+    stats = runner.stats_snapshot()
+    stats["hits"] = 99
+
+    assert runner.stats_snapshot() == {
+        "calls": 0,
+        "hits": 0,
+        "captures": 0,
+        "capture_failures": 0,
+        "evictions": 0,
+        "eager": 0,
+        "cache_size": 0,
+    }
diff --git a/tests/model_executor/models/indextts2/test_enhanced_codec.py b/tests/model_executor/models/indextts2/test_enhanced_codec.py
new file mode 100644
index 000000000..2f82eaf91
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_enhanced_codec.py
@@ -0,0 +1,84 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import torch
+
+from vllm_omni.model_executor.models.indextts2 import codec as codec_module
+from vllm_omni.model_executor.models.indextts2 import preprocess_utils
+from vllm_omni.model_executor.models.indextts2.codec import EnhancedCodec
+
+
+def test_enhanced_codec_decode_restores_hidden_size_and_doubles_time():
+    codec = EnhancedCodec(
+        codebook_size=8,
+        hidden_size=4,
+        codebook_dim=2,
+        vocos_dim=4,
+        vocos_intermediate_dim=8,
+        vocos_num_layers=1,
+        downsample_scale=2,
+    ).eval()
+
+    decoded = codec.decode(torch.tensor([[0, 1, 2]]))
+
+    assert decoded.shape == (1, 6, 4)
+
+
+def test_enhanced_codec_inference_module_does_not_allocate_unused_encoder():
+    codec = EnhancedCodec(
+        codebook_size=8,
+        hidden_size=4,
+        codebook_dim=2,
+        vocos_dim=4,
+        vocos_intermediate_dim=8,
+        vocos_num_layers=1,
+    )
+
+    parameter_names = set(dict(codec.named_parameters()))
+    assert not any(name.startswith("encoder.") for name in parameter_names)
+    assert not any(name.startswith("down.") for name in parameter_names)
+    assert any(name.startswith("decoder.") for name in parameter_names)
+    assert any(name.startswith("quantizer.") for name in parameter_names)
+
+
+def test_semantic_codec_loader_selects_enhanced_checkpoint(tmp_path, monkeypatch):
+    checkpoint = tmp_path / "codec.pth"
+    checkpoint.touch()
+    seen = {}
+
+    class FakeCodec:
+        def load_checkpoint(self, path):
+            seen["path"] = path
+
+        def to(self, **kwargs):
+            seen["to"] = kwargs
+            return self
+
+        def eval(self):
+            return self
+
+        def parameters(self):
+            return ()
+
+    monkeypatch.setattr(codec_module, "EnhancedCodec", lambda **kwargs: FakeCodec())
+    preprocess_utils._semantic_codec_cache.clear()
+
+    codec = preprocess_utils.load_semantic_codec(
+        str(tmp_path),
+        {"codebook_size": 8192},
+        torch.device("cpu"),
+        codec_type="enhanced",
+        checkpoint_name="codec.pth",
+    )
+
+    assert isinstance(codec, FakeCodec)
+    assert seen["path"] == str(checkpoint)
+    assert seen["to"] == {"device": torch.device("cpu"), "dtype": torch.float32}
+
+
+def test_model_asset_resolver_supports_native_checkpoints_layout(tmp_path):
+    checkpoint = tmp_path / "checkpoints" / "codec.pth"
+    checkpoint.parent.mkdir()
+    checkpoint.touch()
+
+    assert preprocess_utils.resolve_model_file(str(tmp_path), "codec.pth") == str(checkpoint)
diff --git a/tests/model_executor/models/indextts2/test_prompt_utils.py b/tests/model_executor/models/indextts2/test_prompt_utils.py
new file mode 100644
index 000000000..fe73e69a5
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_prompt_utils.py
@@ -0,0 +1,202 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import importlib.util
+from pathlib import Path
+from types import SimpleNamespace
+
+import pytest
+
+from vllm_omni.model_executor.models.indextts2 import prompt_utils
+from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+    INDEXTTS25_TOKENIZER_FILE,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+def _load_indextts2_offline_example():
+    example_path = (
+        Path(__file__).resolve().parents[4]
+        / "examples"
+        / "offline_inference"
+        / "text_to_speech"
+        / "indextts2"
+        / "end2end.py"
+    )
+    spec = importlib.util.spec_from_file_location(
+        "indextts2_offline_example_test",
+        example_path,
+    )
+    assert spec is not None and spec.loader is not None
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_offline_main_uses_resolved_stage0_tokenizer_file(monkeypatch, tmp_path):
+    monkeypatch.setenv("VLLM_WORKER_MULTIPROC_METHOD", "spawn")
+    example = _load_indextts2_offline_example()
+    stage0 = SimpleNamespace(engine_args=SimpleNamespace(hf_overrides={"tokenizer_file": "custom-tokenizer.tiktoken"}))
+    fake_omni = SimpleNamespace(
+        stage_configs=[stage0],
+        generate=lambda *args, **kwargs: [],
+    )
+    captured = {}
+
+    monkeypatch.setattr(example, "Omni", lambda **kwargs: fake_omni)
+    monkeypatch.setattr(example, "SamplingParams", lambda **kwargs: kwargs)
+    monkeypatch.setattr(
+        example,
+        "build_request",
+        lambda **kwargs: captured.update(kwargs) or {"additional_information": {}},
+    )
+
+    example.main(
+        SimpleNamespace(
+            model="/model",
+            model_version="2.5",
+            deploy_config="/deploy/custom.yaml",
+            use_gpt_latent=False,
+            stage_init_timeout=300,
+            seed=42,
+            output_dir=str(tmp_path),
+            text="hello",
+            ref_audio=None,
+            emo_audio=None,
+            emo_text=None,
+            emo_vector=None,
+            emo_alpha=None,
+            use_emo_text=False,
+            use_random=False,
+            lang="en",
+            text_normalization=True,
+        )
+    )
+
+    assert captured["tokenizer_file"] == "custom-tokenizer.tiktoken"
+
+
+def test_indextts25_prompt_len_uses_three_conditioning_tokens(monkeypatch):
+    captured = {}
+
+    def fake_prepare(*args, **kwargs):
+        captured.update(kwargs)
+        return [11, 12, 13, 14], 0
+
+    monkeypatch.setattr(
+        prompt_utils,
+        "prepare_indextts25_text",
+        fake_prepare,
+    )
+
+    prompt_len = prompt_utils.estimate_indextts2_prefill_prompt_len(
+        "/model",
+        "hello",
+        model_type="indextts2_5",
+        lang="en",
+        text_normalization=False,
+    )
+
+    # Official prepare_gpt_inputs wraps the language-prefixed tokenizer IDs
+    # with start_text=0 and stop_text=1 before appending start_mel.
+    assert prompt_len == 3 + (4 + 2) + 1
+    assert captured["text_normalization"] is False
+    assert captured["tokenizer_file"] == INDEXTTS25_TOKENIZER_FILE
+
+
+def test_indextts25_prompt_len_uses_custom_tokenizer_file(monkeypatch):
+    captured = {}
+
+    def fake_prepare(*args, **kwargs):
+        captured.update(kwargs)
+        return [11, 12], 0
+
+    monkeypatch.setattr(
+        prompt_utils,
+        "prepare_indextts25_text",
+        fake_prepare,
+    )
+
+    prompt_utils.estimate_indextts2_prefill_prompt_len(
+        "/model",
+        "hello",
+        model_type="indextts2_5",
+        tokenizer_file="custom-tokenizer.tiktoken",
+    )
+
+    assert captured["tokenizer_file"] == "custom-tokenizer.tiktoken"
+
+
+def test_indextts25_prompt_len_filters_existing_text_wrapper_ids(monkeypatch):
+    monkeypatch.setattr(
+        prompt_utils,
+        "prepare_indextts25_text",
+        lambda *args, **kwargs: ([0, 58838, 1, 42, 0], 0),
+    )
+
+    prompt_len = prompt_utils.estimate_indextts2_prefill_prompt_len(
+        "/model",
+        "hello",
+        model_type="indextts2_5",
+        lang="en",
+    )
+
+    assert prompt_len == 3 + (2 + 2) + 1
+
+
+def test_indextts2_prompt_len_ignores_v25_tokenizer_file(monkeypatch):
+    class FakeTokenizer:
+        def encode(self, text, *, add_special_tokens):
+            assert text == "hello"
+            assert add_special_tokens is False
+            return [11, 12]
+
+    def fail_prepare(*args, **kwargs):
+        raise AssertionError("IndexTTS 2 must not use the IndexTTS 2.5 tokenizer")
+
+    monkeypatch.setattr(
+        prompt_utils,
+        "_get_text_tokenizer",
+        lambda model_id_or_path: FakeTokenizer(),
+    )
+    monkeypatch.setattr(
+        prompt_utils,
+        "prepare_indextts25_text",
+        fail_prepare,
+    )
+
+    prompt_len = prompt_utils.estimate_indextts2_prefill_prompt_len(
+        "/model",
+        "hello",
+        model_type="indextts2",
+        tokenizer_file="custom.tiktoken",
+    )
+
+    assert prompt_len == 34 + (2 + 2) + 1
+
+
+def test_indextts25_prompt_ids_preserve_placeholder_value(monkeypatch):
+    captured = {}
+
+    def fake_estimate(*args, **kwargs):
+        captured.update(kwargs)
+        return 10
+
+    monkeypatch.setattr(
+        prompt_utils,
+        "estimate_indextts2_prefill_prompt_len",
+        fake_estimate,
+    )
+
+    prompt_ids = prompt_utils.build_indextts2_prefill_prompt_ids(
+        "/model",
+        "hello",
+        model_type="indextts2_5",
+        lang="en",
+        tokenizer_file="custom-tokenizer.tiktoken",
+        placeholder_token_id=17,
+    )
+
+    assert prompt_ids == [17] * 10
+    assert captured["tokenizer_file"] == "custom-tokenizer.tiktoken"
diff --git a/tests/model_executor/models/indextts2/test_recipe_defaults.py b/tests/model_executor/models/indextts2/test_recipe_defaults.py
new file mode 100644
index 000000000..2ed0ba977
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_recipe_defaults.py
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from pathlib import Path
+
+import yaml
+
+
+def test_indextts25_default_recipe_enables_validated_cfm_batching():
+    recipe_path = Path(__file__).parents[4] / "vllm_omni" / "deploy" / "indextts2_5.yaml"
+    recipe = yaml.safe_load(recipe_path.read_text(encoding="utf-8"))
+    stage1 = next(stage for stage in recipe["stages"] if stage["stage_id"] == 1)
+
+    assert stage1["hf_overrides"]["s2mel_cfm_batch_size"] == 4
diff --git a/tests/model_executor/models/indextts2/test_s2mel_v2_5.py b/tests/model_executor/models/indextts2/test_s2mel_v2_5.py
new file mode 100644
index 000000000..7d7e6e8d2
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_s2mel_v2_5.py
@@ -0,0 +1,1066 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from pathlib import Path
+from types import SimpleNamespace
+
+import pytest
+import torch
+import yaml
+
+from vllm_omni.model_executor.models.indextts2 import indextts2_s2mel_decoder
+from vllm_omni.model_executor.models.indextts2.indextts2_s2mel_decoder import (
+    IndexTTS2S2MelDecoder,
+)
+from vllm_omni.model_executor.models.indextts2.s2mel.modules import (
+    flow_matching,
+)
+from vllm_omni.model_executor.models.indextts2.s2mel.modules.flow_matching import (
+    BASECFM,
+    CFM,
+)
+from vllm_omni.model_executor.models.indextts2.s2mel.modules.gpt_fast import (
+    model as gpt_fast_model,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+class _FakeEnhancedCodec:
+    downsample_scale = 2
+
+    def __init__(self):
+        self.decode_calls = 0
+
+    def decode(self, codes):
+        self.decode_calls += 1
+        return torch.ones(codes.shape[0], codes.shape[1] * 2, 4)
+
+
+class _FakeS2Mel:
+    def forward_gpt(self, latent):
+        return torch.full((*latent.shape[:-1], 4), 2.0)
+
+
+class _FakeBigVGAN:
+    def __init__(self):
+        self.events = []
+
+    def remove_weight_norm(self):
+        self.events.append("remove_weight_norm")
+
+    def to(self, *, device, dtype):
+        self.events.append(("to", device, dtype))
+        return self
+
+    def eval(self):
+        self.events.append("eval")
+        return self
+
+    def parameters(self):
+        return []
+
+
+class _DefaultDtypeBigVGAN(torch.nn.Module):
+    def __init__(self):
+        super().__init__()
+        self.weight = torch.nn.Parameter(torch.ones(1))
+        self.fold_weight_dtype = None
+        self.fold_default_dtype = None
+
+    def remove_weight_norm(self):
+        self.fold_weight_dtype = self.weight.dtype
+        self.fold_default_dtype = torch.get_default_dtype()
+
+
+class _LengthRecordingBigVGAN(torch.nn.Module):
+    def __init__(self):
+        super().__init__()
+        self.input_lengths = []
+
+    def forward(self, mel):
+        self.input_lengths.append(mel.shape[-1])
+        return torch.zeros(
+            mel.shape[0],
+            1,
+            mel.shape[-1] * 256,
+            dtype=mel.dtype,
+            device=mel.device,
+        )
+
+
+class _NoiseEchoCFM(BASECFM):
+    def __init__(self):
+        torch.nn.Module.__init__(self)
+        self.in_channels = 2
+
+    def solve_euler(
+        self,
+        x,
+        x_lens,
+        prompt,
+        mu,
+        style,
+        f0,
+        t_span,
+        inference_cfg_rate=0.5,
+        prompt_lens=None,
+        unpad_data=None,
+    ):
+        del unpad_data
+        return x
+
+
+class _PromptRecordingEstimator(torch.nn.Module):
+    style_as_token = False
+    time_as_token = False
+    is_causal = False
+
+    def __init__(self):
+        super().__init__()
+        self.calls = []
+
+    def forward(
+        self,
+        x,
+        prompt,
+        x_lens,
+        _t,
+        _style,
+        mu,
+        *,
+        pre_mask,
+        unpad_data=None,
+    ):
+        self.calls.append(
+            {
+                "x": x.clone(),
+                "prompt": prompt.clone(),
+                "x_lens": x_lens.clone(),
+                "mu": mu.clone(),
+                "pre_mask": tuple(mask.clone() for mask in pre_mask),
+                "unpad_data": unpad_data,
+            }
+        )
+        return torch.ones_like(x)
+
+
+class _VariablePromptCFM(BASECFM):
+    def __init__(self):
+        torch.nn.Module.__init__(self)
+        self.in_channels = 2
+        self.zero_prompt_speech_token = True
+        self.estimator = _PromptRecordingEstimator()
+
+
+class _GroupingEstimator:
+    def __init__(self):
+        layers = [SimpleNamespace(attention=SimpleNamespace()) for _ in range(2)]
+        self.transformer = SimpleNamespace(
+            layers=layers,
+            freqs_cis=torch.ones(1),
+            max_batch_size=8,
+        )
+
+
+class _GroupingCFM:
+    in_channels = 2
+
+    def __init__(self):
+        self.estimator = _GroupingEstimator()
+        self.calls = []
+
+    def inference(
+        self,
+        mu,
+        x_lens,
+        prompt,
+        style,
+        f0,
+        n_timesteps,
+        temperature=1.0,
+        inference_cfg_rate=0.5,
+        initial_noise=None,
+        prompt_lens=None,
+        unpad_data=None,
+    ):
+        self.calls.append(
+            {
+                "mu": mu.clone(),
+                "x_lens": x_lens.clone(),
+                "prompt": prompt.clone(),
+                "prompt_lens": prompt_lens.clone(),
+                "style": style.clone(),
+                "f0": f0,
+                "n_timesteps": n_timesteps,
+                "temperature": temperature,
+                "inference_cfg_rate": inference_cfg_rate,
+                "initial_noise": initial_noise.clone(),
+                "unpad_data": unpad_data,
+                "full_mask": all(layer.attention._assume_full_mask for layer in self.estimator.transformer.layers),
+            }
+        )
+        return mu[..., 0].unsqueeze(1).expand(-1, self.in_channels, -1).clone()
+
+
+class _OrderRecordingBigVGAN(torch.nn.Module):
+    def __init__(self):
+        super().__init__()
+        self.calls = []
+
+    def forward(self, mel):
+        self.calls.append((int(mel.shape[-1]), float(mel[0, 0, 0])))
+        return mel[:, :1].repeat_interleave(4, dim=-1)
+
+
+class _MetadataRecordingDiffusionAttention(torch.nn.Module):
+    def __init__(self):
+        super().__init__()
+        self.metadata = []
+
+    def forward(self, query, _key, _value, *, attn_metadata):
+        self.metadata.append(attn_metadata)
+        return query
+
+
+class _IdentityQKV(torch.nn.Module):
+    def forward(self, x):
+        return torch.cat([x, x, x], dim=-1)
+
+
+def _make_decoder(*, use_gpt_latent: bool):
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    decoder.use_gpt_latent = use_gpt_latent
+    decoder.semantic_codec_type = "enhanced"
+    decoder.s2mel = _FakeS2Mel()
+    return decoder
+
+
+def test_v25_code_only_semantic_embedding_uses_enhanced_decode():
+    decoder = _make_decoder(use_gpt_latent=False)
+    codec = _FakeEnhancedCodec()
+
+    result = decoder._build_semantic_embedding(
+        codec=codec,
+        mel_codes=torch.tensor([[1, 2, 3]]),
+        latent=None,
+        dtype=torch.float32,
+    )
+
+    assert codec.decode_calls == 1
+    assert result.shape == (1, 6, 4)
+    assert torch.equal(result, torch.ones(1, 6, 4))
+
+
+def test_v25_latent_mode_upsamples_projected_latent_before_addition():
+    decoder = _make_decoder(use_gpt_latent=True)
+    codec = _FakeEnhancedCodec()
+
+    result = decoder._build_semantic_embedding(
+        codec=codec,
+        mel_codes=torch.tensor([[1, 2, 3]]),
+        latent=torch.ones(1, 3, 8),
+        dtype=torch.float32,
+    )
+
+    assert result.shape == (1, 6, 4)
+    assert torch.equal(result, torch.full((1, 6, 4), 3.0))
+
+
+def test_s2mel_payload_latent_policy_must_match_stage_config():
+    decoder = _make_decoder(use_gpt_latent=False)
+
+    decoder._validate_payload_policy([{"use_gpt_latent": False}])
+    with pytest.raises(ValueError, match="use_gpt_latent"):
+        decoder._validate_payload_policy([{"use_gpt_latent": True}])
+
+
+@pytest.mark.parametrize("missing_key", ["mel_codes", "S_ref", "ref_mel", "style"])
+def test_s2mel_payload_contract_requires_non_empty_conditioning(missing_key):
+    payload = {
+        "mel_codes": torch.ones(2, dtype=torch.long),
+        "S_ref": torch.ones(2, 4),
+        "ref_mel": torch.ones(80, 2),
+        "style": torch.ones(192),
+    }
+    payload[missing_key] = torch.empty(0)
+
+    with pytest.raises(ValueError, match=f"non-empty {missing_key}"):
+        IndexTTS2S2MelDecoder._validate_payload_contract([payload])
+
+
+def test_s2mel_target_lengths_apply_request_local_duration_factors():
+    assert IndexTTS2S2MelDecoder._target_lengths(
+        [100, 80],
+        semantic_time_scale=2,
+        mel_code_to_frame_ratio=1.72,
+        duration_factors=[0.5, 2.0],
+    ) == [172, 550]
+
+
+def test_s2mel_duration_factors_default_to_one_without_request_infos():
+    assert IndexTTS2S2MelDecoder._duration_factors([], batch_size=2) == [1.0, 1.0]
+
+
+def test_s2mel_duration_factors_default_missing_request_value_to_one():
+    assert IndexTTS2S2MelDecoder._duration_factors(
+        [{}, {"duration_factor": 0.5}],
+        batch_size=2,
+    ) == [1.0, 0.5]
+
+
+def test_s2mel_duration_factors_accept_supported_bounds():
+    assert IndexTTS2S2MelDecoder._duration_factors(
+        [{"duration_factor": 0.5}, {"duration_factor": 2.0}],
+        batch_size=2,
+    ) == [0.5, 2.0]
+
+
+def test_s2mel_duration_factor_count_must_match_batch_size():
+    with pytest.raises(ValueError) as exc_info:
+        IndexTTS2S2MelDecoder._duration_factors(
+            [{"duration_factor": 1.0}],
+            batch_size=2,
+        )
+
+    assert str(exc_info.value) == "IndexTTS duration-factor batch mismatch: factors=1 batch=2"
+
+
+def test_s2mel_target_length_count_must_match_duration_factors():
+    with pytest.raises(ValueError) as exc_info:
+        IndexTTS2S2MelDecoder._target_lengths(
+            [100, 80],
+            semantic_time_scale=2,
+            mel_code_to_frame_ratio=1.72,
+            duration_factors=[1.0],
+        )
+
+    assert str(exc_info.value) == "IndexTTS target-length batch mismatch: codes=2 factors=1"
+
+
+@pytest.mark.parametrize("duration_factor", [float("nan"), float("inf"), float("-inf"), 0.0, -0.5, 0.49, 2.01])
+def test_s2mel_duration_factors_must_be_finite_and_in_supported_range(duration_factor):
+    with pytest.raises(ValueError) as exc_info:
+        IndexTTS2S2MelDecoder._duration_factors(
+            [{"duration_factor": duration_factor}],
+            batch_size=1,
+        )
+
+    assert str(exc_info.value) == "IndexTTS duration_factor values must be finite and between 0.5 and 2.0"
+
+
+def test_cfm_unpad_data_builder_accounts_for_token_offsets_and_cfg_row_order():
+    indices, cu_seqlens = flow_matching.build_cfm_unpad_data(
+        [3, 5],
+        padded_length=5,
+        token_offset=2,
+        repeat_for_cfg=True,
+        device=torch.device("cpu"),
+    )
+
+    # Effective lengths are [5, 7] and CFG order is
+    # [cond row 0, cond row 1, uncond row 0, uncond row 1]. The second
+    # copy must use the actual padded row offsets (14 and 21), not copied
+    # indices from the conditional half.
+    assert indices.dtype == torch.int64
+    assert torch.equal(
+        indices,
+        torch.tensor(
+            [
+                0,
+                1,
+                2,
+                3,
+                4,
+                7,
+                8,
+                9,
+                10,
+                11,
+                12,
+                13,
+                14,
+                15,
+                16,
+                17,
+                18,
+                21,
+                22,
+                23,
+                24,
+                25,
+                26,
+                27,
+            ],
+            dtype=torch.int64,
+        ),
+    )
+    assert cu_seqlens.dtype == torch.int32
+    assert torch.equal(cu_seqlens, torch.tensor([0, 5, 12, 17, 24], dtype=torch.int32))
+
+
+def test_cfm_inference_uses_explicit_initial_noise():
+    cfm = _NoiseEchoCFM()
+    initial_noise = torch.arange(12, dtype=torch.float32).reshape(1, 2, 6)
+
+    result = cfm.inference(
+        mu=torch.zeros(1, 6, 4),
+        x_lens=torch.tensor([6]),
+        prompt=torch.zeros(1, 80, 0),
+        style=torch.zeros(1, 192),
+        f0=None,
+        n_timesteps=1,
+        temperature=0.5,
+        initial_noise=initial_noise,
+    )
+
+    assert torch.equal(result, initial_noise * 0.5)
+
+
+def test_cfm_variable_prompt_lens_are_applied_per_row_under_cfg_each_step():
+    cfm = _VariablePromptCFM()
+    initial_noise = torch.arange(20, dtype=torch.float32).reshape(2, 2, 5)
+    prompt = torch.tensor(
+        [
+            [[11.0, 91.0, 92.0], [12.0, 93.0, 94.0]],
+            [[21.0, 22.0, 23.0], [24.0, 25.0, 26.0]],
+        ]
+    )
+    mu = torch.arange(20, dtype=torch.float32).reshape(2, 5, 2) + 1
+    prompt_lens = torch.tensor([1, 3], dtype=torch.long)
+    unpad_data = (
+        torch.tensor([0, 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19]),
+        torch.tensor([0, 4, 9, 13, 18], dtype=torch.int32),
+    )
+
+    result = cfm.inference(
+        mu=mu,
+        x_lens=torch.tensor([4, 5], dtype=torch.long),
+        prompt=prompt,
+        prompt_lens=prompt_lens,
+        style=torch.ones(2, 3),
+        f0=None,
+        n_timesteps=2,
+        inference_cfg_rate=0.7,
+        initial_noise=initial_noise,
+        unpad_data=unpad_data,
+    )
+
+    assert len(cfm.estimator.calls) == 2
+    for call in cfm.estimator.calls:
+        # CFG packs conditional rows first and unconditional rows second.
+        assert torch.count_nonzero(call["x"][0, :, :1]) == 0
+        assert torch.count_nonzero(call["x"][1, :, :3]) == 0
+        assert torch.count_nonzero(call["x"][2, :, :1]) == 0
+        assert torch.count_nonzero(call["x"][3, :, :3]) == 0
+        assert torch.equal(call["prompt"][0, :, :1], prompt[0, :, :1])
+        assert torch.count_nonzero(call["prompt"][0, :, 1:]) == 0
+        assert torch.equal(call["prompt"][1, :, :3], prompt[1])
+        assert torch.count_nonzero(call["prompt"][2:]) == 0
+        assert torch.count_nonzero(call["mu"][0, :1]) == 0
+        assert torch.equal(call["mu"][0, 1:], mu[0, 1:])
+        assert torch.count_nonzero(call["mu"][1, :3]) == 0
+        assert torch.equal(call["mu"][1, 3:], mu[1, 3:])
+        assert torch.count_nonzero(call["mu"][2:]) == 0
+        assert torch.equal(call["x_lens"], torch.tensor([4, 5]))
+        assert call["unpad_data"] is unpad_data
+
+    assert torch.count_nonzero(result[0, :, :1]) == 0
+    assert torch.count_nonzero(result[1, :, :3]) == 0
+
+
+def test_seeded_cfm_noise_is_request_local_and_batch_order_independent():
+    kwargs = {
+        "channels": 2,
+        "length": 6,
+        "device": torch.device("cpu"),
+        "dtype": torch.float32,
+    }
+
+    noise_40_42 = IndexTTS2S2MelDecoder._sample_cfm_noise(
+        seeds=[40, 42],
+        **kwargs,
+    )
+    torch.randn(257)
+    noise_42_40 = IndexTTS2S2MelDecoder._sample_cfm_noise(
+        seeds=[42, 40],
+        **kwargs,
+    )
+
+    assert noise_40_42 is not None
+    assert noise_42_40 is not None
+    assert torch.equal(noise_40_42[0], noise_42_40[1])
+    assert torch.equal(noise_40_42[1], noise_42_40[0])
+    assert not torch.equal(noise_40_42[0], noise_40_42[1])
+
+
+def test_unseeded_cfm_noise_preserves_upstream_global_rng_behavior():
+    assert (
+        IndexTTS2S2MelDecoder._sample_cfm_noise(
+            seeds=[None, None],
+            channels=2,
+            length=6,
+            device=torch.device("cpu"),
+            dtype=torch.float32,
+        )
+        is None
+    )
+
+
+def test_variable_length_cfm_groups_pack_batch_crop_and_restore_request_order():
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    decoder.diffusion_steps = 2
+    decoder.inference_cfg_rate = 0.7
+    decoder.s2mel_dit_cuda_graph = False
+    cfm = _GroupingCFM()
+
+    # Original request order is deliberately different from total-length order.
+    # Stable sort by ref+target must produce groups [1, 3] and [2, 0].
+    ref_lengths = [4, 1, 2, 2]
+    target_lengths = [3, 2, 3, 1]
+    seeds = [101, 202, 303, 404]
+    prompt_markers = [110.0, 120.0, 130.0, 140.0]
+    target_markers = [10.0, 20.0, 30.0, 40.0]
+
+    prompt_condition = torch.full((4, 4, 2), -777.0)
+    cond = torch.full((4, 3, 2), -999.0)
+    ref_mel = torch.full((4, 2, 4), -555.0)
+    style = torch.zeros(4, 3)
+    for index, (ref_len, target_len) in enumerate(zip(ref_lengths, target_lengths)):
+        prompt_condition[index, :ref_len] = prompt_markers[index]
+        cond[index, :target_len] = target_markers[index]
+        ref_mel[index, :, :ref_len] = prompt_markers[index] + 1
+        style[index] = index + 1
+
+    mels = decoder._run_cfm_groups(
+        cfm=cfm,
+        cond=cond,
+        prompt_condition=prompt_condition,
+        ref_mel=ref_mel,
+        style=style,
+        target_lengths=target_lengths,
+        ref_lengths=ref_lengths,
+        seeds=seeds,
+        max_group_size=2,
+    )
+
+    assert len(cfm.calls) == 2
+    assert [call["x_lens"].tolist() for call in cfm.calls] == [[3, 3], [5, 7]]
+    assert [call["prompt_lens"].tolist() for call in cfm.calls] == [[1, 2], [2, 4]]
+    assert [call["style"][:, 0].tolist() for call in cfm.calls] == [[2.0, 4.0], [3.0, 1.0]]
+
+    first, second = cfm.calls
+    assert torch.equal(first["mu"][0, :1], torch.full((1, 2), 120.0))
+    assert torch.equal(first["mu"][0, 1:3], torch.full((2, 2), 20.0))
+    assert torch.equal(first["mu"][1, :2], torch.full((2, 2), 140.0))
+    assert torch.equal(first["mu"][1, 2:3], torch.full((1, 2), 40.0))
+    assert torch.equal(second["mu"][0, :2], torch.full((2, 2), 130.0))
+    assert torch.equal(second["mu"][0, 2:5], torch.full((3, 2), 30.0))
+    assert torch.count_nonzero(second["mu"][0, 5:]) == 0
+    assert torch.equal(second["mu"][1, :4], torch.full((4, 2), 110.0))
+    assert torch.equal(second["mu"][1, 4:7], torch.full((3, 2), 10.0))
+
+    assert torch.equal(first["prompt"][0, :, :1], torch.full((2, 1), 121.0))
+    assert torch.count_nonzero(first["prompt"][0, :, 1:]) == 0
+    assert torch.equal(second["prompt"][0, :, :2], torch.full((2, 2), 131.0))
+    assert torch.count_nonzero(second["prompt"][0, :, 2:]) == 0
+
+    # Equal total lengths have no tail padding and may use the full-mask path;
+    # the mixed-length group must explicitly disable it.
+    assert [call["full_mask"] for call in cfm.calls] == [True, False]
+    assert first["unpad_data"] is None
+    ragged_indices, ragged_cu_seqlens = second["unpad_data"]
+    assert torch.equal(
+        ragged_indices,
+        torch.tensor(
+            [
+                0,
+                1,
+                2,
+                3,
+                4,
+                7,
+                8,
+                9,
+                10,
+                11,
+                12,
+                13,
+                14,
+                15,
+                16,
+                17,
+                18,
+                21,
+                22,
+                23,
+                24,
+                25,
+                26,
+                27,
+            ]
+        ),
+    )
+    assert torch.equal(ragged_cu_seqlens, torch.tensor([0, 5, 12, 17, 24], dtype=torch.int32))
+
+    for call, sorted_indices in zip(cfm.calls, ([1, 3], [2, 0])):
+        for row, request_index in enumerate(sorted_indices):
+            x_len = ref_lengths[request_index] + target_lengths[request_index]
+            generator = torch.Generator(device="cpu")
+            generator.manual_seed(seeds[request_index])
+            expected = torch.randn((2, x_len), generator=generator)
+            assert torch.equal(call["initial_noise"][row, :, :x_len], expected)
+            assert torch.count_nonzero(call["initial_noise"][row, :, x_len:]) == 0
+
+    assert [tuple(mel.shape) for mel in mels] == [
+        (2, 3),
+        (2, 2),
+        (2, 3),
+        (2, 1),
+    ]
+    for mel, marker in zip(mels, target_markers):
+        assert torch.equal(mel, torch.full_like(mel, marker))
+
+
+def test_bigvgan_folds_weight_norm_before_low_precision_cast(monkeypatch):
+    from vllm_omni.model_executor.models.indextts2.s2mel.modules import bigvgan
+
+    model = _FakeBigVGAN()
+    monkeypatch.setattr(
+        bigvgan.BigVGAN,
+        "from_pretrained",
+        lambda *_args, **_kwargs: model,
+    )
+    monkeypatch.setattr(
+        indextts2_s2mel_decoder,
+        "_patch_bigvgan_compat",
+        lambda _cls: None,
+    )
+    monkeypatch.setattr(
+        indextts2_s2mel_decoder,
+        "_repo_prefetch_lock",
+        lambda _name: None,
+    )
+    indextts2_s2mel_decoder._bigvgan_models.clear()
+
+    loaded = indextts2_s2mel_decoder._load_bigvgan(
+        "fake-bigvgan",
+        torch.device("cpu"),
+        torch.bfloat16,
+    )
+
+    assert loaded is model
+    assert model.events == [
+        "remove_weight_norm",
+        ("to", torch.device("cpu"), torch.bfloat16),
+        "eval",
+    ]
+
+
+def test_bigvgan_folds_weight_norm_in_fp32_under_low_precision_loader_context(
+    monkeypatch,
+):
+    from vllm_omni.model_executor.models.indextts2.s2mel.modules import bigvgan
+
+    monkeypatch.setattr(
+        bigvgan.BigVGAN,
+        "from_pretrained",
+        lambda *_args, **_kwargs: _DefaultDtypeBigVGAN(),
+    )
+    monkeypatch.setattr(
+        indextts2_s2mel_decoder,
+        "_patch_bigvgan_compat",
+        lambda _cls: None,
+    )
+    monkeypatch.setattr(
+        indextts2_s2mel_decoder,
+        "_repo_prefetch_lock",
+        lambda _name: None,
+    )
+    indextts2_s2mel_decoder._bigvgan_models.clear()
+
+    previous_dtype = torch.get_default_dtype()
+    torch.set_default_dtype(torch.bfloat16)
+    try:
+        loaded = indextts2_s2mel_decoder._load_bigvgan(
+            "fake-bigvgan",
+            torch.device("cpu"),
+            torch.bfloat16,
+        )
+
+        assert loaded.fold_weight_dtype == torch.float32
+        assert loaded.fold_default_dtype == torch.float32
+        assert loaded.weight.dtype == torch.bfloat16
+        assert torch.get_default_dtype() == torch.bfloat16
+    finally:
+        torch.set_default_dtype(previous_dtype)
+
+
+def _cfm_estimator_with_mixed_parameter_types():
+    return torch.nn.ModuleDict(
+        {
+            "linear": torch.nn.Linear(3, 2),
+            "conv": torch.nn.Conv1d(2, 4, kernel_size=3, bias=False),
+            "norm": torch.nn.LayerNorm(4),
+        }
+    )
+
+
+def test_cfm_estimator_bf16_precast_only_casts_linear_and_conv1d():
+    estimator = _cfm_estimator_with_mixed_parameter_types()
+
+    parameter_count = indextts2_s2mel_decoder._precast_cfm_estimator_bf16(
+        estimator,
+        enabled=True,
+    )
+
+    assert parameter_count == 32
+    assert estimator["linear"].weight.dtype == torch.bfloat16
+    assert estimator["linear"].bias.dtype == torch.bfloat16
+    assert estimator["conv"].weight.dtype == torch.bfloat16
+    assert estimator["norm"].weight.dtype == torch.float32
+    assert estimator["norm"].bias.dtype == torch.float32
+
+
+def test_cfm_estimator_bf16_precast_disabled_preserves_fp32():
+    estimator = _cfm_estimator_with_mixed_parameter_types()
+
+    parameter_count = indextts2_s2mel_decoder._precast_cfm_estimator_bf16(
+        estimator,
+        enabled=False,
+    )
+
+    assert parameter_count == 0
+    assert all(parameter.dtype == torch.float32 for parameter in estimator.parameters())
+
+
+def test_v25_full_mask_fast_path_is_guarded_independently_of_cuda_graph():
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    decoder.s2mel_dit_cuda_graph = False
+    layers = [SimpleNamespace(attention=SimpleNamespace()) for _ in range(13)]
+    estimator = SimpleNamespace(
+        transformer=SimpleNamespace(layers=layers),
+    )
+
+    decoder._set_dit_full_mask_fast_path(estimator, enabled=True)
+    decoder._enable_dit_cuda_graph(estimator)
+
+    assert all(layer.attention._assume_full_mask is True for layer in layers)
+    assert not hasattr(estimator, "_cuda_graph_runner")
+
+    decoder._set_dit_full_mask_fast_path(estimator, enabled=False)
+
+    assert all(layer.attention._assume_full_mask is False for layer in layers)
+
+
+def test_indextts_attention_keeps_padding_metadata_model_local(monkeypatch):
+    attention = object.__new__(gpt_fast_model.Attention)
+    torch.nn.Module.__init__(attention)
+    attention.n_head = 1
+    attention.n_local_heads = 1
+    attention.head_dim = 2
+    attention.dim = 2
+    attention.wqkv = _IdentityQKV()
+    attention.wo = torch.nn.Identity()
+    attention.diff_attn = _MetadataRecordingDiffusionAttention()
+    monkeypatch.setattr(gpt_fast_model, "apply_rotary_emb", lambda tensor, _freqs: tensor)
+
+    x = torch.ones(2, 3, 2)
+    mask = torch.tensor(
+        [
+            [[[True, True, True], [True, True, True], [True, True, True]]],
+            [[[True, True, False], [True, True, False], [True, True, False]]],
+        ]
+    )
+    attention._assume_full_mask = False
+    unpad_data = (
+        torch.tensor([0, 1, 2, 3, 4], dtype=torch.int64),
+        torch.tensor([0, 3, 5], dtype=torch.int32),
+    )
+
+    attention(x, torch.empty(0), mask, unpad_data=unpad_data)
+
+    padded_metadata = attention.diff_attn.metadata[-1]
+    assert padded_metadata.extra == {}
+    assert torch.equal(padded_metadata.attn_mask, mask[:, 0, 0, :])
+
+    attention._assume_full_mask = True
+    attention(x, torch.empty(0), mask)
+
+    assert attention.diff_attn.metadata[-1] is None
+
+    all_true_mask = torch.ones_like(mask)
+    for unknown_state in ("missing", None):
+        if unknown_state == "missing":
+            del attention._assume_full_mask
+        else:
+            attention._assume_full_mask = unknown_state
+
+        attention(x, torch.empty(0), all_true_mask)
+
+        fallback_metadata = attention.diff_attn.metadata[-1]
+        assert fallback_metadata.extra == {}
+        assert torch.equal(fallback_metadata.attn_mask, all_true_mask[:, 0, 0, :])
+
+
+def test_v25_ref_mel_lengths_come_from_unpadded_shapes():
+    ref_mels = [
+        torch.zeros(80, 5),
+        torch.ones(80, 3),
+    ]
+
+    assert IndexTTS2S2MelDecoder._ref_mel_lengths(ref_mels) == [5, 3]
+    assert IndexTTS2S2MelDecoder._ref_mel_lengths([None, ref_mels[1]]) == []
+
+
+def test_v25_resolved_vocoder_source_is_cached(monkeypatch):
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    decoder.model_path = "/models/indextts25"
+    decoder.config = SimpleNamespace(vocoder={"name": "fake-bigvgan"})
+    decoder._resolved_vocoder_source = None
+    calls = []
+
+    def fake_resolve(model_path, vocoder_name):
+        calls.append((model_path, vocoder_name))
+        return "/models/indextts25/hf_cache/bigvgan"
+
+    monkeypatch.setattr(
+        indextts2_s2mel_decoder,
+        "_resolve_bigvgan_source",
+        fake_resolve,
+    )
+
+    first = decoder._get_resolved_vocoder_source()
+    second = decoder._get_resolved_vocoder_source()
+
+    assert first == "/models/indextts25/hf_cache/bigvgan"
+    assert second == first
+    assert calls == [("/models/indextts25", "fake-bigvgan")]
+
+
+def test_stage1_preload_does_not_swallow_cuda_runtime_failure(monkeypatch):
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    torch.nn.Module.__init__(decoder)
+    decoder.s2mel = torch.nn.Linear(1, 1)
+    decoder.model_path = "/models/indextts25"
+    decoder.semantic_codec_type = "enhanced"
+    decoder.s2mel_vocoder_bf16 = False
+    decoder.s2mel_vocoder_cuda_graph = False
+    decoder._resolved_vocoder_source = "/models/bigvgan"
+    decoder.config = SimpleNamespace(
+        semantic_codec={},
+        semantic_codec_checkpoint="codec.pth",
+    )
+
+    def fail_load(*_args, **_kwargs):
+        raise RuntimeError("CUDA error: illegal memory access")
+
+    monkeypatch.setattr(
+        indextts2_s2mel_decoder,
+        "_load_bigvgan",
+        fail_load,
+    )
+
+    with pytest.raises(RuntimeError, match="CUDA error"):
+        decoder._warmup_external_models()
+
+
+def _runtime_decoder(*, compile_dit: bool):
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    calls = []
+    decoder.s2mel = SimpleNamespace(
+        enable_torch_compile=lambda *, mode="default": calls.append("compile"),
+    )
+    decoder.s2mel_dit_torch_compile = compile_dit
+    decoder.s2mel_dit_torch_compile_mode = "default"
+    decoder.s2mel_dit_cuda_graph = False
+    decoder._dit_runtime_configured = False
+    return decoder, calls
+
+
+def test_configure_dit_runtime_compiles_only_on_cuda():
+    cpu_decoder, cpu_calls = _runtime_decoder(compile_dit=True)
+    cuda_decoder, cuda_calls = _runtime_decoder(compile_dit=True)
+
+    cpu_decoder._configure_dit_runtime(torch.device("cpu"))
+    cuda_decoder._configure_dit_runtime(torch.device("cuda"))
+    cuda_decoder._configure_dit_runtime(torch.device("cuda"))
+
+    assert cpu_calls == []
+    assert cuda_calls == ["compile"]
+
+
+def test_cfm_torch_compile_forwards_reduce_overhead_mode(monkeypatch):
+    cfm = object.__new__(CFM)
+    torch.nn.Module.__init__(cfm)
+    eager_estimator = torch.nn.Identity()
+    cfm.estimator = eager_estimator
+    object.__setattr__(cfm, "_eager_estimator", eager_estimator)
+    calls = []
+
+    def fake_compile(model, **kwargs):
+        calls.append((model, kwargs))
+        return model
+
+    monkeypatch.setattr(flow_matching.torch, "compile", fake_compile)
+
+    cfm.enable_torch_compile(mode="reduce-overhead")
+
+    assert calls == [
+        (
+            eager_estimator,
+            {
+                "mode": "reduce-overhead",
+                "fullgraph": True,
+                "dynamic": True,
+            },
+        )
+    ]
+
+
+def test_configure_dit_runtime_forwards_compile_mode_once():
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    calls = []
+    decoder.s2mel = SimpleNamespace(
+        enable_torch_compile=lambda *, mode="default": calls.append(mode),
+    )
+    decoder.s2mel_dit_torch_compile = True
+    decoder.s2mel_dit_torch_compile_mode = "reduce-overhead"
+    decoder.s2mel_dit_cuda_graph = False
+    decoder._dit_runtime_configured = False
+
+    decoder._configure_dit_runtime(torch.device("cuda"))
+    decoder._configure_dit_runtime(torch.device("cuda"))
+
+    assert calls == ["reduce-overhead"]
+
+
+def _vocoder_decoder(*, compile_vocoder: bool, graph_vocoder: bool = False):
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    decoder.s2mel_vocoder_torch_compile = compile_vocoder
+    decoder.s2mel_vocoder_cuda_graph = graph_vocoder
+    decoder._compiled_vocoder = None
+    return decoder
+
+
+def test_vocoder_torch_compile_disabled_returns_original_model(monkeypatch):
+    decoder = _vocoder_decoder(compile_vocoder=False)
+    bigvgan = _LengthRecordingBigVGAN()
+    runner_factory = getattr(decoder, "_get_vocoder_runner", None)
+
+    assert runner_factory is not None
+
+    def unexpected_compile(*_args, **_kwargs):
+        pytest.fail("torch.compile must stay disabled")
+
+    monkeypatch.setattr(indextts2_s2mel_decoder.torch, "compile", unexpected_compile)
+
+    runner = runner_factory(
+        bigvgan,
+        torch.device("cuda"),
+        torch.bfloat16,
+    )
+
+    assert runner is bigvgan
+
+
+def test_vocoder_torch_compile_is_cached_and_preserves_exact_lengths(monkeypatch):
+    decoder = _vocoder_decoder(compile_vocoder=True)
+    bigvgan = _LengthRecordingBigVGAN()
+    runner_factory = getattr(decoder, "_get_vocoder_runner", None)
+    compile_calls = []
+
+    assert runner_factory is not None
+
+    def fake_compile(fn, **kwargs):
+        compile_calls.append((fn, kwargs))
+        return fn
+
+    monkeypatch.setattr(indextts2_s2mel_decoder.torch, "compile", fake_compile)
+
+    first = runner_factory(
+        bigvgan,
+        torch.device("cuda"),
+        torch.bfloat16,
+    )
+    second = runner_factory(
+        bigvgan,
+        torch.device("cuda"),
+        torch.bfloat16,
+    )
+    first(torch.zeros(1, 80, 137))
+    second(torch.zeros(1, 80, 221))
+
+    assert first is second
+    assert bigvgan.input_lengths == [137, 221]
+    assert len(compile_calls) == 1
+    assert compile_calls[0][0] == bigvgan.forward
+    assert compile_calls[0][1] == {
+        "mode": "default",
+        "fullgraph": False,
+        "dynamic": True,
+    }
+
+
+def test_bigvgan_vocodes_cropped_mels_one_request_at_a_time_in_order():
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    vocoder = _OrderRecordingBigVGAN()
+    mels = [
+        torch.full((2, 3), 0.1),
+        torch.full((2, 2), 0.2),
+        torch.full((2, 4), 0.3),
+    ]
+
+    wavs = decoder._vocode_mels(
+        mels=mels,
+        vocode=vocoder,
+        voc_dtype=torch.float32,
+    )
+
+    assert [length for length, _ in vocoder.calls] == [3, 2, 4]
+    assert [marker for _, marker in vocoder.calls] == pytest.approx([0.1, 0.2, 0.3])
+    assert [tuple(wav.shape) for wav in wavs] == [(12,), (8,), (16,)]
+    assert [float(wav[0]) for wav in wavs] == pytest.approx([0.1, 0.2, 0.3])
+
+
+def test_vocoder_torch_compile_rejects_cuda_graph_combination():
+    decoder = _vocoder_decoder(
+        compile_vocoder=True,
+        graph_vocoder=True,
+    )
+    runner_factory = getattr(decoder, "_get_vocoder_runner", None)
+
+    assert runner_factory is not None
+    with pytest.raises(ValueError, match="mutually exclusive"):
+        runner_factory(
+            _LengthRecordingBigVGAN(),
+            torch.device("cuda"),
+            torch.bfloat16,
+        )
+
+
+@pytest.mark.parametrize("recipe_name", ["indextts2_5.yaml"])
+def test_v25_recipe_enables_dynamic_dit_compile(recipe_name):
+    repo_root = Path(__file__).parents[4]
+    recipe_path = repo_root / "vllm_omni" / "deploy" / recipe_name
+    recipe = yaml.safe_load(recipe_path.read_text(encoding="utf-8"))
+    stage1 = next(stage for stage in recipe["stages"] if stage["stage_id"] == 1)
+    overrides = stage1["hf_overrides"]
+
+    assert overrides["s2mel_dit_cuda_graph"] is False
+    assert overrides["s2mel_dit_bf16"] is True
+    assert overrides["s2mel_dit_torch_compile"] is True
+    assert overrides.get("s2mel_dit_torch_compile_mode") == "default"
+    assert overrides.get("s2mel_vocoder_torch_compile") is False
+    assert overrides.get("s2mel_vocoder_cuda_graph", False) is False
+
+
+def test_v25_default_recipe_selects_validated_triton_backend_for_stage0():
+    repo_root = Path(__file__).parents[4]
+    recipe_path = repo_root / "vllm_omni" / "deploy" / "indextts2_5.yaml"
+    recipe = yaml.safe_load(recipe_path.read_text(encoding="utf-8"))
+    stage0 = next(stage for stage in recipe["stages"] if stage["stage_id"] == 0)
+
+    assert stage0["attention_backend"] == "TRITON_ATTN"
+    assert stage0["enable_chunked_prefill"] is False
+    assert stage0["max_num_batched_tokens"] == stage0["max_model_len"]
diff --git a/tests/model_executor/models/indextts2/test_stage_input_processor.py b/tests/model_executor/models/indextts2/test_stage_input_processor.py
new file mode 100644
index 000000000..f216ef2b0
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_stage_input_processor.py
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from types import SimpleNamespace
+
+import pytest
+import torch
+
+from vllm_omni.model_executor.stage_input_processors.indextts2 import (
+    STOP_MEL_TOKEN,
+    talker2s2mel_full_payload,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+def test_no_latent_full_payload_uses_sampled_output_ids_and_strips_stop():
+    request = SimpleNamespace(
+        request_id="req-1",
+        output_token_ids=[17, 23, STOP_MEL_TOKEN],
+        sampling_params=SimpleNamespace(seed=42),
+    )
+    payload = {
+        "meta": {
+            "use_gpt_latent": False,
+            "S_ref": torch.ones(1, 4),
+            "ref_mel": torch.ones(1, 80, 3),
+            "style": torch.ones(1, 192),
+        }
+    }
+
+    result = talker2s2mel_full_payload(None, payload, request)
+
+    assert result is not None
+    assert result["mel_codes"].tolist() == [[17, 23]]
+    assert result["code_lens"].tolist() == [2]
+    assert result["use_gpt_latent"] is False
+    assert result["seed"] == 42
+
+
+def test_no_latent_full_payload_rejects_legacy_payload_codes():
+    request = SimpleNamespace(
+        request_id="legacy",
+        output_token_ids=[],
+        sampling_params=SimpleNamespace(seed=None),
+    )
+    payload = {
+        "codes": {"mel": torch.tensor([31, 37, STOP_MEL_TOKEN])},
+        "meta": {"use_gpt_latent": False},
+    }
+
+    with pytest.raises(ValueError, match="no completed output_token_ids"):
+        talker2s2mel_full_payload(None, payload, request)
diff --git a/tests/model_executor/models/indextts2/test_talker_v2_5.py b/tests/model_executor/models/indextts2/test_talker_v2_5.py
new file mode 100644
index 000000000..c916354e3
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_talker_v2_5.py
@@ -0,0 +1,476 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from types import SimpleNamespace
+
+import pytest
+import torch
+from vllm.config import CompilationMode
+
+from vllm_omni.model_executor.models.indextts2.indextts2_talker import (
+    IndexTTS2TalkerForConditionalGeneration,
+    _normalize_indextts_checkpoint_key,
+    _require_exact_indextts_prefill_span,
+    resolve_indextts_conditioning_policy,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+def test_v25_conditioning_policy():
+    policy = resolve_indextts_conditioning_policy("indextts2_5")
+
+    assert policy.prefix_tokens == 3
+    assert policy.uses_conformer_perceiver is False
+    assert policy.uses_campplus_projection is True
+    assert policy.uses_language_embedding is True
+
+
+def test_v2_conditioning_policy_is_unchanged():
+    policy = resolve_indextts_conditioning_policy("indextts2")
+
+    assert policy.prefix_tokens == 34
+    assert policy.uses_conformer_perceiver is True
+    assert policy.uses_campplus_projection is False
+    assert policy.uses_language_embedding is False
+
+
+def test_v25_text_tokens_wrap_language_prefixed_ids_with_start_and_stop(
+    monkeypatch,
+):
+    import vllm_omni.model_executor.models.indextts2.text_processing_v2_5 as text_processing
+
+    monkeypatch.setattr(
+        text_processing,
+        "prepare_indextts25_text",
+        lambda *args, **kwargs: ([58838, 42], 7),
+    )
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    talker.conditioning_policy = resolve_indextts_conditioning_policy("indextts2_5")
+    talker.model_path = "/model"
+    talker.config = SimpleNamespace(tokenizer_file="tokenizer.tiktoken")
+
+    token_ids, language_id = talker._tokenize_text(
+        "hello",
+        torch.device("cpu"),
+        lang="ja",
+    )
+
+    assert token_ids.tolist() == [[0, 58838, 42, 1]]
+    assert language_id.tolist() == [7]
+
+
+def test_v25_text_tokens_filter_existing_start_and_stop_ids(monkeypatch):
+    import vllm_omni.model_executor.models.indextts2.text_processing_v2_5 as text_processing
+
+    monkeypatch.setattr(
+        text_processing,
+        "prepare_indextts25_text",
+        lambda *args, **kwargs: ([0, 58838, 1, 42, 0], 7),
+    )
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    talker.conditioning_policy = resolve_indextts_conditioning_policy("indextts2_5")
+    talker.model_path = "/model"
+    talker.config = SimpleNamespace(tokenizer_file="tokenizer.tiktoken")
+
+    token_ids, language_id = talker._tokenize_text(
+        "hello",
+        torch.device("cpu"),
+        lang="en",
+    )
+
+    assert token_ids.tolist() == [[0, 58838, 42, 1]]
+    assert language_id.tolist() == [7]
+
+
+def test_native_fsdp_checkpoint_keys_are_normalized_at_every_nesting_level():
+    assert _normalize_indextts_checkpoint_key("_fsdp_wrapped_module.spk_emb_proj.weight") == "spk_emb_proj.weight"
+    assert (
+        _normalize_indextts_checkpoint_key("_fsdp_wrapped_module.mel_embedding._fsdp_wrapped_module.weight")
+        == "mel_embedding.weight"
+    )
+
+
+def test_prefill_span_mismatch_fails_instead_of_padding_or_truncating():
+    for actual_span_len in (9, 11):
+        with pytest.raises(
+            ValueError,
+            match="model_type=indextts2_5.*lang=es.*text_token_count=6",
+        ):
+            _require_exact_indextts_prefill_span(
+                actual_span_len=actual_span_len,
+                scheduled_span_len=10,
+                model_type="indextts2_5",
+                lang="es",
+                text_token_count=6,
+            )
+
+
+def test_matching_prefill_span_is_accepted():
+    _require_exact_indextts_prefill_span(
+        actual_span_len=10,
+        scheduled_span_len=10,
+        model_type="indextts2_5",
+        lang="en",
+        text_token_count=6,
+    )
+
+
+def _make_minimal_talker(
+    monkeypatch,
+    *,
+    model_type,
+    use_gpt_latent,
+):
+    import vllm_omni.model_executor.models.indextts2.indextts2_talker as talker_module
+
+    seen = {}
+
+    def fake_parallel_lm_head(vocab_size, hidden_size, *, bias=False, **_kwargs):
+        seen["bias"] = bias
+        return torch.nn.Linear(hidden_size, vocab_size, bias=bias)
+
+    monkeypatch.setattr(talker_module, "ParallelLMHead", fake_parallel_lm_head)
+    monkeypatch.setattr(
+        talker_module,
+        "make_layers",
+        lambda *_args, **_kwargs: (
+            0,
+            1,
+            torch.nn.ModuleList([torch.nn.Linear(8, 8)]),
+        ),
+    )
+    monkeypatch.setattr(
+        talker_module,
+        "get_pp_group",
+        lambda: SimpleNamespace(is_last_rank=lambda: True),
+    )
+    monkeypatch.setattr(talker_module, "get_speaker_cache", object)
+    monkeypatch.setattr(
+        talker_module,
+        "LogitsProcessor",
+        lambda *_args, **_kwargs: object(),
+    )
+    monkeypatch.setattr(
+        talker_module,
+        "ConformerEncoder",
+        lambda **_kwargs: torch.nn.Linear(1, 1),
+    )
+    monkeypatch.setattr(
+        talker_module,
+        "PerceiverResampler",
+        lambda *_args, **_kwargs: torch.nn.Linear(1, 1),
+    )
+
+    gpt = {
+        "model_dim": 8,
+        "layers": 0,
+        "heads": 1,
+        "max_mel_tokens": 4,
+        "max_text_tokens": 4,
+        "number_mel_codes": 16,
+        "start_mel_token": 14,
+        "stop_mel_token": 15,
+        "number_text_tokens": 32,
+        "condition_num_latent": 1,
+        "condition_module": {},
+        "emo_condition_module": {},
+    }
+    config = SimpleNamespace(
+        gpt=gpt,
+        model_type=model_type,
+        use_gpt_latent=use_gpt_latent,
+        gpt_checkpoint="gpt.pth",
+    )
+    vllm_config = SimpleNamespace(
+        model_config=SimpleNamespace(model="/model", hf_config=config),
+        cache_config=None,
+        quant_config=None,
+        compilation_config=SimpleNamespace(mode=CompilationMode.NONE),
+    )
+
+    return (
+        IndexTTS2TalkerForConditionalGeneration(vllm_config=vllm_config),
+        seen,
+    )
+
+
+@pytest.mark.parametrize(
+    ("model_type", "use_gpt_latent"),
+    [
+        ("indextts2", True),
+        ("indextts2_5", False),
+    ],
+)
+def test_mel_head_preserves_official_checkpoint_bias_and_hidden_payload_policy(
+    monkeypatch,
+    model_type,
+    use_gpt_latent,
+):
+    talker, seen = _make_minimal_talker(
+        monkeypatch,
+        model_type=model_type,
+        use_gpt_latent=use_gpt_latent,
+    )
+
+    assert seen["bias"] is True
+    assert talker.mel_head.bias is not None
+    assert talker.omni_pooler_payload_include_hidden is use_gpt_latent
+    assert talker.omni_payload_at_request_end is (model_type == "indextts2_5")
+
+
+def test_v2_load_weights_loads_exact_mel_head_bias_parameter(monkeypatch):
+    import vllm_omni.model_executor.models.indextts2.indextts2_talker as talker_module
+
+    talker, _ = _make_minimal_talker(
+        monkeypatch,
+        model_type="indextts2",
+        use_gpt_latent=True,
+    )
+    checkpoint = {
+        name: parameter.detach().clone() for name, parameter in talker.named_parameters(remove_duplicate=False)
+    }
+    expected_bias = torch.arange(
+        talker.number_mel_codes,
+        dtype=talker.mel_head.bias.dtype,
+    )
+    checkpoint["mel_head.bias"] = expected_bias
+    with torch.no_grad():
+        talker.mel_head.bias.zero_()
+
+    monkeypatch.setattr(
+        talker_module,
+        "resolve_model_file",
+        lambda *_args, **_kwargs: "/model/gpt.pth",
+    )
+    monkeypatch.setattr(
+        talker_module.torch,
+        "load",
+        lambda *_args, **_kwargs: checkpoint,
+    )
+    monkeypatch.setattr(
+        talker_module,
+        "is_pp_missing_parameter",
+        lambda *_args, **_kwargs: False,
+    )
+    monkeypatch.setattr(
+        talker,
+        "_warmup_external_models",
+        lambda _device: None,
+    )
+
+    loaded = talker.load_weights([])
+
+    assert "mel_head.bias" in loaded
+    torch.testing.assert_close(talker.mel_head.bias, expected_bias)
+
+
+def test_compute_logits_passes_mel_head_bias_to_logits_processor():
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    torch.nn.Module.__init__(talker)
+    talker.mel_head = torch.nn.Linear(3, 4, bias=True)
+    hidden_states = torch.zeros(1, 3)
+    seen = {}
+
+    def fake_logits_processor(head, hidden, **kwargs):
+        seen["head"] = head
+        seen["hidden"] = hidden
+        seen.update(kwargs)
+        return hidden
+
+    talker.logits_processor = fake_logits_processor
+
+    result = talker.compute_logits(hidden_states)
+
+    assert result is hidden_states
+    assert seen["head"] is talker.mel_head
+    assert seen["hidden"] is hidden_states
+    assert seen["embedding_bias"] is talker.mel_head.bias
+
+
+def _make_cached_v25_prefill_talker(monkeypatch):
+    talker, _ = _make_minimal_talker(
+        monkeypatch,
+        model_type="indextts2_5",
+        use_gpt_latent=False,
+    )
+    talker._speaker_cache = SimpleNamespace(
+        make_cache_key=lambda *_args: "cached-speaker",
+        get=lambda _key: {
+            "S_ref": torch.ones(1, 3, 8),
+            "ref_mel": torch.ones(1, 80, 3),
+            "style": torch.ones(1, 192),
+            "spk_cond_emb": torch.ones(1, 3, 8),
+        },
+    )
+    monkeypatch.setattr(
+        talker,
+        "_compute_emotion_vector",
+        lambda **_kwargs: torch.zeros(1, talker.model_dim),
+    )
+    monkeypatch.setattr(
+        talker,
+        "_tokenize_text",
+        lambda *_args, **_kwargs: (torch.tensor([[1]]), None),
+    )
+    return talker
+
+
+def test_prefill_preserves_duration_factor_in_metadata(monkeypatch):
+    talker = _make_cached_v25_prefill_talker(monkeypatch)
+
+    _, _, info_update = talker._preprocess_prefill(
+        torch.zeros(5, dtype=torch.long),
+        None,
+        {
+            "text": ["hello"],
+            "voice": ["/speaker.wav"],
+            "voice_name": ["cached"],
+            "duration_factor": [0.5],
+        },
+        span_len=5,
+    )
+
+    assert info_update["meta"]["duration_factor"] == 0.5
+
+
+@pytest.mark.parametrize("duration_factor", [0.49, 2.01])
+def test_prefill_rejects_duration_factor_outside_supported_range(monkeypatch, duration_factor):
+    talker = _make_cached_v25_prefill_talker(monkeypatch)
+
+    with pytest.raises(
+        ValueError,
+        match="^IndexTTS 2.5 duration_factor must be between 0.5 and 2.0$",
+    ):
+        talker._preprocess_prefill(
+            torch.zeros(5, dtype=torch.long),
+            None,
+            {
+                "text": ["hello"],
+                "voice": ["/speaker.wav"],
+                "voice_name": ["cached"],
+                "duration_factor": [duration_factor],
+            },
+            span_len=5,
+        )
+
+
+def test_no_latent_sampled_token_payload_emits_only_first_step_metadata():
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    talker.use_gpt_latent = False
+    hidden = torch.zeros(1, 8)
+    info = {
+        "codes": {"mel": torch.tensor([17])},
+        "meta": {
+            "mel_code_count": 1,
+            "S_ref": torch.ones(1, 4),
+            "ref_mel": torch.ones(1, 80, 3),
+            "style": torch.ones(1, 192),
+            "duration_factor": 0.5,
+        },
+    }
+
+    first_decode_output = talker.make_omni_output(
+        hidden,
+        model_intermediate_buffer=[info],
+    )
+
+    assert "codes" not in first_decode_output.multimodal_outputs
+    assert "hidden_states" not in first_decode_output.multimodal_outputs
+    assert first_decode_output.multimodal_outputs["meta"][0]["S_ref"] is info["meta"]["S_ref"]
+    assert first_decode_output.multimodal_outputs["meta"][0]["duration_factor"] == 0.5
+
+    later = talker.make_omni_output(
+        hidden,
+        model_intermediate_buffer=[
+            {
+                "codes": {"mel": torch.tensor([23])},
+                "meta": {"mel_code_count": 2},
+            }
+        ],
+    )
+    assert later.multimodal_outputs == {"meta": [{"use_gpt_latent": False}]}
+
+
+def test_first_decode_payload_defaults_missing_duration_factor_to_one():
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    talker.use_gpt_latent = False
+    hidden = torch.zeros(1, 8)
+    info = {
+        "codes": {"mel": torch.tensor([17])},
+        "meta": {
+            "mel_code_count": 1,
+            "S_ref": torch.ones(1, 4),
+            "ref_mel": torch.ones(1, 80, 3),
+            "style": torch.ones(1, 192),
+        },
+    }
+
+    output = talker.make_omni_output(
+        hidden,
+        model_intermediate_buffer=[info],
+    )
+
+    assert output.multimodal_outputs["meta"][0]["duration_factor"] == 1.0
+
+
+def test_latent_sampled_token_payload_keeps_aligned_gpu_deltas():
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    talker.use_gpt_latent = True
+    hidden = torch.zeros(1, 8)
+    info = {
+        "codes": {"mel": torch.tensor([17])},
+        "meta": {
+            "mel_code_count": 1,
+            "latent_acc": torch.arange(8, dtype=torch.float32).reshape(1, 8),
+            "duration_factor": 1.0,
+        },
+    }
+
+    output = talker.make_omni_output(
+        hidden,
+        model_intermediate_buffer=[info],
+    )
+
+    assert output.multimodal_outputs["codes"]["mel"][0].tolist() == [[17]]
+    assert output.multimodal_outputs["hidden_states"]["latent"][0].tolist() == [list(range(8))]
+
+
+def test_v25_default_emotion_reuses_speaker_w2v_features(monkeypatch):
+    talker = object.__new__(IndexTTS2TalkerForConditionalGeneration)
+    speaker_features = torch.zeros(1, 4, 1024)
+    expected = torch.ones(1, 1280)
+    seen = {}
+
+    def fake_merge(spk_cond_emb, emo_cond_emb, alpha):
+        seen["spk"] = spk_cond_emb
+        seen["emo"] = emo_cond_emb
+        seen["alpha"] = alpha
+        return expected
+
+    monkeypatch.setattr(talker, "_merge_emovec", fake_merge)
+
+    result = talker._compute_emotion_vector(
+        wav_16k=None,
+        speaker_audio_path="/speaker.wav",
+        emo_audio_path=None,
+        emo_voice_name=None,
+        main_text="hello",
+        use_emo_text=False,
+        emo_text=None,
+        emo_vector=None,
+        emo_alpha=0.25,
+        use_random=False,
+        style=torch.zeros(1, 192),
+        spk_cond_emb=speaker_features,
+        w2v_model=None,
+        w2v_proc=None,
+        device=torch.device("cpu"),
+    )
+
+    assert result is expected
+    assert seen == {
+        "spk": speaker_features,
+        "emo": speaker_features,
+        "alpha": 1.0,
+    }
diff --git a/tests/model_executor/models/indextts2/test_tokenizer_v2_5.py b/tests/model_executor/models/indextts2/test_tokenizer_v2_5.py
new file mode 100644
index 000000000..d0b42be08
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_tokenizer_v2_5.py
@@ -0,0 +1,244 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import builtins
+
+import pytest
+
+from vllm_omni.model_executor.models.indextts2 import text_processing_v2_5
+from vllm_omni.model_executor.models.indextts2.text_processing_v2_5 import (
+    apply_pronunciation_annotations,
+    clean_indextts25_text,
+    prepare_indextts25_text,
+)
+from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+    INDEXTTS25_SPECIAL_TOKENS,
+    INDEXTTS25_VOCAB_SIZE,
+    LANGUAGE_DICT,
+    lang_to_token,
+    normalize_language_code,
+    resolve_indextts25_tokenizer_file,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+def test_special_token_layout_matches_official_checkpoint_vocab():
+    assert len(INDEXTTS25_SPECIAL_TOKENS) == 1673
+    assert len(set(INDEXTTS25_SPECIAL_TOKENS)) == 1673
+    assert 58836 + len(INDEXTTS25_SPECIAL_TOKENS) == INDEXTTS25_VOCAB_SIZE
+    assert INDEXTTS25_VOCAB_SIZE == 60509
+
+
+def test_pronunciation_annotations_select_english_and_chinese_markers():
+    assert apply_pronunciation_annotations("<going|G OW1 . IH0 NG>") == (
+        "<|SPECIAL_TOKEN_1|>G OW1 . IH0 NG<|SPECIAL_TOKEN_1|>"
+    )
+    assert apply_pronunciation_annotations("<行|xing2>") == ("<|SPECIAL_TOKEN_2|>XING2<|SPECIAL_TOKEN_2|>")
+
+
+def test_prepare_text_applies_language_prefix_case_and_annotation(monkeypatch):
+    captured = {}
+
+    def fake_encode(text, *, model_dir, tokenizer_file):
+        captured["text"] = text
+        captured["model_dir"] = model_dir
+        captured["tokenizer_file"] = tokenizer_file
+        return [7, 8, 9]
+
+    monkeypatch.setattr(text_processing_v2_5, "encode_indextts25_text", fake_encode)
+
+    token_ids, lang_id = prepare_indextts25_text(
+        "HELLO <行|xing2>",
+        lang="zh",
+        model_dir="/model",
+        text_normalization=False,
+    )
+
+    assert token_ids == [7, 8, 9]
+    assert lang_id == LANGUAGE_DICT["zh"]
+    assert captured == {
+        "text": "<|zh|> hello <|SPECIAL_TOKEN_2|>XING2<|SPECIAL_TOKEN_2|>",
+        "model_dir": "/model",
+        "tokenizer_file": "multilingual_zh_ja_yue_char_del.tiktoken",
+    }
+
+
+def test_mandarin_alias_is_an_intentional_vllm_omni_convenience():
+    assert normalize_language_code("Mandarin") == "zh"
+    assert lang_to_token("mandarin") == LANGUAGE_DICT["zh"]
+
+
+def test_invalid_language_does_not_fall_back_to_common():
+    with pytest.raises(ValueError, match="Unsupported IndexTTS 2.5 language"):
+        lang_to_token("xx-invalid")
+
+
+def test_zhen_uses_mixed_normalization():
+    calls = []
+
+    def fake_mixed_normalizer(text):
+        calls.append(text)
+        return "MIXED"
+
+    original = text_processing_v2_5._normalize_zh_or_en
+    text_processing_v2_5._normalize_zh_or_en = fake_mixed_normalizer
+    try:
+        result = text_processing_v2_5._normalize_with_official_backend(
+            "中文 and English",
+            "zhen",
+        )
+    finally:
+        text_processing_v2_5._normalize_zh_or_en = original
+
+    assert calls == ["中文 and English"]
+    assert result == "MIXED"
+
+
+def test_spanish_normalization_does_not_hide_broken_dependencies(monkeypatch):
+    original_import = builtins.__import__
+
+    def controlled_import(name, *args, **kwargs):
+        if name == "nemo_text_processing.text_normalization.normalize":
+            raise RuntimeError("broken NeMo grammar")
+        return original_import(name, *args, **kwargs)
+
+    monkeypatch.setattr(builtins, "__import__", controlled_import)
+
+    with pytest.raises(RuntimeError, match="broken NeMo grammar"):
+        text_processing_v2_5._normalize_with_official_backend("hola", "es")
+
+
+def test_zhen_keeps_literal_prefix_and_uses_common_embedding(monkeypatch):
+    captured = {}
+
+    def fake_encode(text, *, model_dir, tokenizer_file):
+        captured["text"] = text
+        return [7, 8, 9]
+
+    monkeypatch.setattr(text_processing_v2_5, "encode_indextts25_text", fake_encode)
+
+    token_ids, lang_id = prepare_indextts25_text(
+        "HELLO 中文",
+        lang="zhen",
+        model_dir="/model",
+        text_normalization=False,
+    )
+
+    assert token_ids == [7, 8, 9]
+    assert captured["text"] == "<|zhen|> hello 中文"
+    assert lang_id == LANGUAGE_DICT["common"]
+    assert "<|zhen|>" not in INDEXTTS25_SPECIAL_TOKENS
+    assert "<|common|>" not in INDEXTTS25_SPECIAL_TOKENS
+
+
+@pytest.mark.parametrize(
+    ("text", "expected"),
+    [
+        ("，，，", "…"),
+        ("测试，，，结束", "测试…结束"),
+    ],
+)
+def test_repeated_full_width_commas_use_longest_first_cleanup(text, expected):
+    assert clean_indextts25_text(text) == expected
+
+
+def test_default_text_normalizer_is_shared_by_prompt_and_talker(monkeypatch):
+    calls = []
+
+    def fake_normalizer(text, lang):
+        calls.append((text, lang))
+        return "twenty five percent"
+
+    monkeypatch.setattr(
+        text_processing_v2_5,
+        "_normalize_with_official_backend",
+        fake_normalizer,
+    )
+
+    result = text_processing_v2_5.normalize_indextts25_text(
+        "25%",
+        lang="en",
+        text_normalization=True,
+    )
+
+    assert calls == [("25%", "en")]
+    assert result == "twenty five percent"
+
+
+def test_mixed_text_uses_official_content_routing_and_protection(monkeypatch):
+    calls = []
+
+    class FakeNormalizer:
+        def __init__(self, lang):
+            self.lang = lang
+
+        def normalize(self, text):
+            calls.append((self.lang, text))
+            return text.replace("<H>", " <H> ").replace("5", "five")
+
+    monkeypatch.setattr(
+        text_processing_v2_5,
+        "_load_wetext_normalizer",
+        lambda lang: FakeNormalizer(lang),
+    )
+
+    result = text_processing_v2_5._normalize_with_official_backend(
+        "GPT-5-nano 中文 xuan4",
+        "en",
+    )
+
+    assert calls[0][0] == "zh"
+    assert result == "GPT-five-nano 中文 XVAN4"
+
+
+def test_tokenizer_resolves_native_checkpoints_subdirectory(tmp_path):
+    tokenizer = tmp_path / "checkpoints" / "multilingual_zh_ja_yue_char_del.tiktoken"
+    tokenizer.parent.mkdir()
+    tokenizer.touch()
+
+    assert resolve_indextts25_tokenizer_file(str(tmp_path)) == str(tokenizer)
+
+
+@pytest.mark.parametrize(
+    ("lang", "text", "expected"),
+    [
+        (
+            "es",
+            "En la actualidad se continúa utilizando una corona abierta.",
+            "<|es|> EN LA ACTUALIDAD SE CONTINÚA UTILIZANDO UNA CORONA ABIERTA.",
+        ),
+        (
+            "ar",
+            "فكلُّها خياراتٌ اتَّخذتَها بنفسِك.",
+            "<|ar|> فكلُّها خياراتٌ اتَّخذتَها بنفسِك.",
+        ),
+    ],
+)
+def test_official_spanish_and_arabic_cases_preserve_expected_text_contract(
+    monkeypatch,
+    lang,
+    text,
+    expected,
+):
+    captured = {}
+
+    def fake_encode(value, *, model_dir, tokenizer_file):
+        captured["text"] = value
+        return [1]
+
+    monkeypatch.setattr(
+        text_processing_v2_5,
+        "encode_indextts25_text",
+        fake_encode,
+    )
+
+    _, lang_id = prepare_indextts25_text(
+        text,
+        lang=lang,
+        model_dir="/model",
+        text_normalization=False,
+    )
+
+    assert captured["text"] == expected
+    assert lang_id == LANGUAGE_DICT[lang]
diff --git a/tests/model_executor/models/indextts2/test_wavenet_ragged.py b/tests/model_executor/models/indextts2/test_wavenet_ragged.py
new file mode 100644
index 000000000..d3269989b
--- /dev/null
+++ b/tests/model_executor/models/indextts2/test_wavenet_ragged.py
@@ -0,0 +1,196 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from types import SimpleNamespace
+
+import pytest
+import torch
+
+from vllm_omni.model_executor.models.indextts2.indextts2_s2mel_decoder import (
+    IndexTTS2S2MelDecoder,
+)
+from vllm_omni.model_executor.models.indextts2.s2mel.modules.wavenet import WN
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+def _make_wavenet() -> WN:
+    torch.manual_seed(0)
+    return WN(
+        hidden_channels=2,
+        kernel_size=5,
+        dilation_rate=1,
+        n_layers=8,
+        gin_channels=2,
+        p_dropout=0.0,
+        causal=False,
+    ).eval()
+
+
+def _sequence_mask(lengths: torch.Tensor, max_length: int) -> torch.Tensor:
+    positions = torch.arange(max_length, device=lengths.device)
+    return (positions.unsqueeze(0) < lengths.unsqueeze(1)).unsqueeze(1)
+
+
+def _singleton_outputs(
+    wavenet: WN,
+    inputs: torch.Tensor,
+    lengths: list[int],
+    conditioning: torch.Tensor,
+) -> list[torch.Tensor]:
+    # This is the independent oracle: every request ends at the physical tensor
+    # boundary and therefore uses SConv1d's original reflect-padding behavior.
+    wavenet._assume_full_mask = True
+    return [
+        wavenet(
+            inputs[row : row + 1, :, :length],
+            torch.ones(1, 1, length, dtype=torch.bool),
+            g=conditioning[row : row + 1],
+        )
+        for row, length in enumerate(lengths)
+    ]
+
+
+def test_ragged_wavenet_matches_original_singleton_reflect_boundaries():
+    wavenet = _make_wavenet()
+    lengths = [6, 5, 4, 3]
+    inputs = torch.randn(len(lengths), 2, max(lengths))
+    conditioning = torch.randn(len(lengths), 2, 1)
+    expected = _singleton_outputs(wavenet, inputs, lengths, conditioning)
+
+    mask = _sequence_mask(torch.tensor(lengths), inputs.shape[-1])
+    wavenet._assume_full_mask = False
+    # Keep deliberately non-zero invalid tails. The first WaveNet layer sees
+    # transformer output before the recurrent mask has cleared those values.
+    actual = wavenet(inputs, mask, g=conditioning)
+
+    for row, (length, singleton) in enumerate(zip(lengths, expected)):
+        torch.testing.assert_close(
+            actual[row : row + 1, :, :length],
+            singleton,
+            rtol=1e-5,
+            atol=1e-6,
+        )
+
+
+def test_wavenet_exposes_minimum_safe_ragged_length():
+    # kernel=5, dilation=1 has two right-reflect ghost positions, so a
+    # logical row must contain at least three frames before it can use the
+    # vectorized ragged path. Shorter rows stay on original singleton SConv1d.
+    assert _make_wavenet().ragged_min_length == 3
+
+
+def test_cfm_grouping_isolates_rows_too_short_for_logical_reflect():
+    groups = IndexTTS2S2MelDecoder._cfm_group_indices(
+        sorted_indices=[0, 1, 2, 3, 4],
+        total_lengths=[0, 1, 2, 3, 6],
+        max_group_size=2,
+        min_ragged_length=3,
+    )
+
+    assert groups == [[0], [1], [2], [3, 4]]
+
+
+def test_ragged_wavenet_preserves_cfg_cond_uncond_row_order():
+    wavenet = _make_wavenet()
+    base_lengths = [3, 6]
+    conditional = torch.randn(2, 2, 6)
+    unconditional = torch.randn(2, 2, 6)
+    cfg_inputs = torch.cat([conditional, unconditional], dim=0)
+    cfg_lengths = base_lengths + base_lengths
+    cfg_conditioning = torch.randn(4, 2, 1)
+    expected = _singleton_outputs(
+        wavenet,
+        cfg_inputs,
+        cfg_lengths,
+        cfg_conditioning,
+    )
+
+    mask = _sequence_mask(torch.tensor(cfg_lengths), cfg_inputs.shape[-1])
+    wavenet._assume_full_mask = False
+    actual = wavenet(cfg_inputs, mask, g=cfg_conditioning)
+
+    for row, (length, singleton) in enumerate(zip(cfg_lengths, expected)):
+        torch.testing.assert_close(
+            actual[row : row + 1, :, :length],
+            singleton,
+            rtol=1e-5,
+            atol=1e-6,
+        )
+
+
+def test_full_mask_wavenet_path_is_bit_exact_with_original_path():
+    wavenet = _make_wavenet()
+    inputs = torch.randn(3, 2, 6)
+    mask = torch.ones(3, 1, 6, dtype=torch.bool)
+    conditioning = torch.randn(3, 2, 1)
+
+    if hasattr(wavenet, "_assume_full_mask"):
+        del wavenet._assume_full_mask
+    expected = wavenet(inputs, mask, g=conditioning)
+
+    wavenet._assume_full_mask = True
+    actual = wavenet(inputs, mask, g=conditioning)
+
+    assert torch.equal(actual, expected)
+
+
+@pytest.mark.skipif(not hasattr(torch, "compile"), reason="torch.compile unavailable")
+def test_ragged_wavenet_is_one_dynamic_fullgraph():
+    wavenet = _make_wavenet()
+    lengths = [3, 6]
+    inputs = torch.randn(2, 2, 6)
+    conditioning = torch.randn(2, 2, 1)
+    mask = _sequence_mask(torch.tensor(lengths), inputs.shape[-1])
+    expected = _singleton_outputs(wavenet, inputs, lengths, conditioning)
+    wavenet._assume_full_mask = False
+
+    compiled = torch.compile(
+        wavenet,
+        backend="eager",
+        fullgraph=True,
+        dynamic=True,
+    )
+    actual = compiled(inputs, mask, g=conditioning)
+
+    for row, (length, singleton) in enumerate(zip(lengths, expected)):
+        torch.testing.assert_close(
+            actual[row : row + 1, :, :length],
+            singleton,
+            rtol=1e-5,
+            atol=1e-6,
+        )
+
+
+def test_decoder_full_mask_switch_also_controls_wavenet_boundary_path():
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    attention_layers = [SimpleNamespace(attention=SimpleNamespace()) for _ in range(2)]
+    estimator = SimpleNamespace(
+        transformer=SimpleNamespace(layers=attention_layers),
+        wavenet=SimpleNamespace(),
+    )
+
+    decoder._set_dit_full_mask_fast_path(estimator, enabled=False)
+
+    assert all(layer.attention._assume_full_mask is False for layer in attention_layers)
+    assert estimator.wavenet._assume_full_mask is False
+
+    decoder._set_dit_full_mask_fast_path(estimator, enabled=True)
+
+    assert all(layer.attention._assume_full_mask is True for layer in attention_layers)
+    assert estimator.wavenet._assume_full_mask is True
+
+
+def test_decoder_full_mask_switch_unwraps_compiled_estimator():
+    decoder = object.__new__(IndexTTS2S2MelDecoder)
+    attention_layers = [SimpleNamespace(attention=SimpleNamespace()) for _ in range(2)]
+    eager_estimator = SimpleNamespace(
+        transformer=SimpleNamespace(layers=attention_layers),
+        wavenet=SimpleNamespace(),
+    )
+    compiled_estimator = SimpleNamespace(_orig_mod=eager_estimator)
+
+    decoder._set_dit_full_mask_fast_path(compiled_estimator, enabled=False)
+
+    assert all(layer.attention._assume_full_mask is False for layer in attention_layers)
+    assert eager_estimator.wavenet._assume_full_mask is False
diff --git a/tests/model_executor/models/qwen3_tts/test_code_predictor_dtype.py b/tests/model_executor/models/qwen3_tts/test_code_predictor_dtype.py
index 5e31c2cbd..20f8eb2f0 100644
--- a/tests/model_executor/models/qwen3_tts/test_code_predictor_dtype.py
+++ b/tests/model_executor/models/qwen3_tts/test_code_predictor_dtype.py
@@ -57,6 +57,7 @@ def _build_mock_modules(mocker: MockerFixture) -> dict[str, object]:
     platforms_mock = mocker.MagicMock()
     platforms_mock.current_omni_platform.supports_torch_inductor.return_value = False
     platforms_mock.current_omni_platform.is_npu.return_value = False
+    platforms_mock.current_omni_platform.is_xpu.return_value = False
 
     logger_mock = mocker.MagicMock()
     logger_mock.init_logger = lambda name: mocker.MagicMock()
@@ -284,6 +285,28 @@ class TestCodePredictorDtypeAlignment:
         predictor._setup_compile()
         assert predictor._model_dtype == torch.float16
 
+    def test_setup_compile_uses_eager_on_xpu(self, mocker: MockerFixture, loaded_target_classes) -> None:
+        """XPU should avoid the torch.compile path used by CUDA."""
+        _, _, code_predictor_wrapper, _, _ = loaded_target_classes
+        cp_config, talker_config = _make_tiny_config(loaded_target_classes)
+        vllm_config = _make_vllm_config(mocker, max_num_seqs=2)
+
+        predictor = code_predictor_wrapper(
+            vllm_config=vllm_config,
+            config=cp_config,
+            talker_config=talker_config,
+        )
+
+        common_mod = sys.modules["vllm_omni.model_executor.models.common.qwen3_code_predictor"]
+        mocker.patch.object(common_mod.current_omni_platform, "supports_torch_inductor", return_value=True)
+        mocker.patch.object(common_mod.current_omni_platform, "is_xpu", return_value=True)
+        compile_mock = mocker.patch.object(common_mod.torch, "compile")
+
+        predictor._setup_compile()
+
+        compile_mock.assert_not_called()
+        assert predictor._compiled_model_fwd == predictor.model.forward
+
     def test_forward_with_mismatched_input_dtype(self, mocker: MockerFixture, loaded_target_classes) -> None:
         """forward() should not crash when inputs are float32 but model is float16."""
         _, _, code_predictor_wrapper, _, _ = loaded_target_classes
diff --git a/tests/model_executor/stage_input_processors/test_indextts2.py b/tests/model_executor/stage_input_processors/test_indextts2.py
index 1380b99ff..5aa9ae4ab 100644
--- a/tests/model_executor/stage_input_processors/test_indextts2.py
+++ b/tests/model_executor/stage_input_processors/test_indextts2.py
@@ -116,6 +116,7 @@ def test_strip_stop_token_all_stop():
 
 def _conditioning_tensors():
     return {
+        "use_gpt_latent": True,
         "S_ref": torch.randn(1, 3, LATENT_DIM),
         "ref_mel": torch.randn(1, 80, 5),
         "style": torch.randn(1, 4),
@@ -143,6 +144,8 @@ def test_talker2s2mel_full_payload_flat_keys_builds_s2mel_contract():
         "meta.S_ref": cond["S_ref"],
         "meta.ref_mel": cond["ref_mel"],
         "meta.style": cond["style"],
+        "meta.use_gpt_latent": True,
+        "meta.duration_factor": 0.5,
     }
 
     result = talker2s2mel_full_payload(None, payload, SimpleNamespace(request_id="r-flat"))
@@ -156,6 +159,45 @@ def test_talker2s2mel_full_payload_flat_keys_builds_s2mel_contract():
     assert result["ref_mel"].device.type == "cpu"
     assert result["style"].device.type == "cpu"
     assert result["S_ref"].data_ptr() != cond["S_ref"].data_ptr()
+    assert result["duration_factor"] == 0.5
+
+
+def test_talker2s2mel_full_payload_defaults_missing_duration_factor_to_one():
+    cond = _conditioning_tensors()
+    payload = {
+        "codes.mel": torch.tensor([[10], [20]]),
+        "hidden_states.latent": torch.randn(2, LATENT_DIM),
+        "meta.S_ref": cond["S_ref"],
+        "meta.ref_mel": cond["ref_mel"],
+        "meta.style": cond["style"],
+        "meta.use_gpt_latent": True,
+    }
+
+    result = talker2s2mel_full_payload(None, payload, SimpleNamespace(request_id="r-default-duration"))
+
+    assert result is not None
+    assert result["duration_factor"] == 1.0
+
+
+def test_talker2s2mel_full_payload_preserves_explicit_request_seed():
+    cond = _conditioning_tensors()
+    payload = {
+        "codes.mel": torch.tensor([[10], [20]]),
+        "hidden_states.latent": torch.randn(2, LATENT_DIM),
+        "meta.S_ref": cond["S_ref"],
+        "meta.ref_mel": cond["ref_mel"],
+        "meta.style": cond["style"],
+        "meta.use_gpt_latent": True,
+    }
+    request = SimpleNamespace(
+        request_id="r-seeded",
+        sampling_params=SimpleNamespace(seed=0),
+    )
+
+    result = talker2s2mel_full_payload(None, payload, request)
+
+    assert result is not None
+    assert result["seed"] == 0
 
 
 def test_talker2s2mel_full_payload_nested_fallback_input():
@@ -206,7 +248,7 @@ def test_talker2s2mel_full_payload_trims_stop_token_and_matching_latent():
     assert result["code_lens"].tolist() == [2]
 
 
-def test_talker2s2mel_full_payload_crops_mel_latent_to_common_length():
+def test_talker2s2mel_full_payload_rejects_mel_latent_length_mismatch():
     cond = _conditioning_tensors()
     payload = {
         "codes.mel": torch.tensor([[1], [2], [3], [4]]),
@@ -214,14 +256,44 @@ def test_talker2s2mel_full_payload_crops_mel_latent_to_common_length():
         "meta": cond,
     }
 
-    result = talker2s2mel_full_payload(None, payload, SimpleNamespace(request_id="r-crop"))
+    with pytest.raises(ValueError, match="mel/latent length mismatch"):
+        talker2s2mel_full_payload(None, payload, SimpleNamespace(request_id="r-crop"))
+
+
+def test_talker2s2mel_full_payload_v25_code_only_does_not_invent_latent():
+    cond = _conditioning_tensors()
+    payload = {
+        "meta.use_gpt_latent": False,
+        "meta.S_ref": cond["S_ref"],
+        "meta.ref_mel": cond["ref_mel"],
+        "meta.style": cond["style"],
+    }
+
+    request = SimpleNamespace(
+        request_id="r-v25",
+        output_token_ids=[3, 4, STOP_MEL_TOKEN],
+    )
+    result = talker2s2mel_full_payload(None, payload, request)
 
     assert result is not None
-    assert result["mel_codes"].tolist() == [[1, 2]]
-    assert result["latent"].shape == (1, 2, LATENT_DIM)
+    assert result["mel_codes"].tolist() == [[3, 4]]
     assert result["code_lens"].tolist() == [2]
+    assert result["use_gpt_latent"] is False
+    assert "latent" not in result
 
 
-def test_talker2s2mel_full_payload_missing_required_fields_returns_none():
-    assert talker2s2mel_full_payload(None, {"hidden_states.latent": torch.randn(1, LATENT_DIM)}, None) is None
-    assert talker2s2mel_full_payload(None, {"codes.mel": torch.tensor([[1]])}, None) is None
+def test_talker2s2mel_full_payload_latent_mode_rejects_missing_latent():
+    payload = {
+        "codes.mel": torch.tensor([[3], [4], [STOP_MEL_TOKEN]]),
+        "meta.use_gpt_latent": True,
+    }
+
+    with pytest.raises(ValueError, match="missing hidden_states.latent"):
+        talker2s2mel_full_payload(None, payload, SimpleNamespace(request_id="r-latent"))
+
+
+def test_talker2s2mel_full_payload_missing_required_fields_raises():
+    with pytest.raises(ValueError, match="missing meta.use_gpt_latent"):
+        talker2s2mel_full_payload(None, {"hidden_states.latent": torch.randn(1, LATENT_DIM)}, None)
+    with pytest.raises(ValueError, match="missing meta.use_gpt_latent"):
+        talker2s2mel_full_payload(None, {"codes.mel": torch.tensor([[1]])}, None)
diff --git a/tests/test_indextts2_optional_dependencies.py b/tests/test_indextts2_optional_dependencies.py
new file mode 100644
index 000000000..cc3c46b63
--- /dev/null
+++ b/tests/test_indextts2_optional_dependencies.py
@@ -0,0 +1,155 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import builtins
+import importlib.util
+import platform
+import sys
+import types
+from pathlib import Path
+
+import pytest
+import tomllib
+from packaging.requirements import Requirement
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+ROOT = Path(__file__).parents[1]
+TEXT_PROCESSING_PATH = ROOT / "vllm_omni" / "model_executor" / "models" / "indextts2" / "text_processing_v2_5.py"
+INDEXTTS2_FRONTEND_PACKAGES = {
+    "fugashi",
+    "unidic-lite",
+    "wetext",
+    "wetextprocessing",
+}
+INSTALL_COMMAND = "pip install 'vllm-omni[indextts2]'"
+
+
+def _load_text_processing_module(monkeypatch: pytest.MonkeyPatch):
+    package_name = "_indextts2_optional_dependencies_test"
+    package = types.ModuleType(package_name)
+    package.__path__ = [str(TEXT_PROCESSING_PATH.parent)]
+    tokenizer = types.ModuleType(f"{package_name}.tokenizer_v2_5")
+    tokenizer.INDEXTTS25_TOKENIZER_FILE = "tokenizer.tiktoken"
+    tokenizer.encode_indextts25_text = lambda *args, **kwargs: []
+    tokenizer.lang_to_token = lambda lang: 0
+    tokenizer.normalize_language_code = lambda lang: lang
+    monkeypatch.setitem(sys.modules, package_name, package)
+    monkeypatch.setitem(sys.modules, tokenizer.__name__, tokenizer)
+
+    module_name = f"{package_name}.text_processing_v2_5"
+    spec = importlib.util.spec_from_file_location(module_name, TEXT_PROCESSING_PATH)
+    assert spec is not None and spec.loader is not None
+    module = importlib.util.module_from_spec(spec)
+    monkeypatch.setitem(sys.modules, module_name, module)
+    spec.loader.exec_module(module)
+    return module
+
+
+def _requirements_from_file(path: Path) -> list[Requirement]:
+    requirements = []
+    for raw_line in path.read_text().splitlines():
+        line = raw_line.split("#", 1)[0].strip()
+        if not line:
+            continue
+        if line.startswith(("-r ", "--requirement ")):
+            included = line.split(maxsplit=1)[1]
+            requirements.extend(_requirements_from_file(path.parent / included))
+            continue
+        requirements.append(Requirement(line))
+    return requirements
+
+
+def _block_import(monkeypatch: pytest.MonkeyPatch, package: str) -> None:
+    original_import = builtins.__import__
+
+    def controlled_import(name, *args, **kwargs):
+        if name == package or name.startswith(f"{package}."):
+            raise ModuleNotFoundError(f"No module named {package!r}", name=package)
+        return original_import(name, *args, **kwargs)
+
+    monkeypatch.setattr(builtins, "__import__", controlled_import)
+
+
+def test_indextts2_extra_declares_platform_specific_frontend_dependencies():
+    project = tomllib.loads((ROOT / "pyproject.toml").read_text())
+    requirements = [Requirement(value) for value in project["project"]["optional-dependencies"]["indextts2"]]
+
+    assert {
+        (requirement.name.lower(), str(requirement.specifier), str(requirement.marker) if requirement.marker else None)
+        for requirement in requirements
+    } == {
+        ("fugashi", ">=1.2.0", None),
+        ("unidic-lite", ">=1.0.0", None),
+        ("wetext", ">=0.0.9", 'sys_platform != "linux"'),
+        ("wetextprocessing", "", 'sys_platform == "linux"'),
+    }
+
+
+def test_common_requirements_exclude_indextts2_frontend_dependencies():
+    requirements = _requirements_from_file(ROOT / "requirements" / "common.txt")
+
+    assert not ({requirement.name.lower() for requirement in requirements} & INDEXTTS2_FRONTEND_PACKAGES)
+
+
+def test_wetext_normalizer_constructor_error_propagates(monkeypatch):
+    text_processing_v2_5 = _load_text_processing_module(monkeypatch)
+    sentinel = RuntimeError("wetext constructor sentinel")
+
+    class FailingNormalizer:
+        def __init__(self, *args, **kwargs):
+            raise sentinel
+
+    wetext = types.ModuleType("wetext")
+    wetext.Normalizer = FailingNormalizer
+    monkeypatch.setitem(sys.modules, "wetext", wetext)
+    monkeypatch.setattr(platform, "system", lambda: "Darwin")
+
+    with pytest.raises(RuntimeError) as exc_info:
+        text_processing_v2_5._load_wetext_normalizer("zh")
+
+    assert exc_info.value is sentinel
+
+
+def test_japanese_tagger_constructor_error_propagates(monkeypatch):
+    text_processing_v2_5 = _load_text_processing_module(monkeypatch)
+    sentinel = RuntimeError("fugashi constructor sentinel")
+
+    fugashi = types.ModuleType("fugashi")
+
+    def failing_tagger():
+        raise sentinel
+
+    fugashi.Tagger = failing_tagger
+    monkeypatch.setitem(sys.modules, "fugashi", fugashi)
+    monkeypatch.setitem(sys.modules, "unidic_lite", types.ModuleType("unidic_lite"))
+
+    with pytest.raises(RuntimeError) as exc_info:
+        text_processing_v2_5._load_japanese_tagger()
+
+    assert exc_info.value is sentinel
+
+
+def test_missing_wetext_backend_reports_indextts2_extra(monkeypatch):
+    text_processing_v2_5 = _load_text_processing_module(monkeypatch)
+    text_processing_v2_5._load_wetext_normalizer.cache_clear()
+    monkeypatch.setattr(platform, "system", lambda: "Darwin")
+    _block_import(monkeypatch, "wetext")
+
+    with pytest.raises(RuntimeError, match="IndexTTS 2.5 text normalization") as exc_info:
+        text_processing_v2_5._load_wetext_normalizer("zh")
+
+    assert INSTALL_COMMAND in str(exc_info.value)
+    text_processing_v2_5._load_wetext_normalizer.cache_clear()
+
+
+def test_missing_japanese_tagger_reports_indextts2_extra(monkeypatch):
+    text_processing_v2_5 = _load_text_processing_module(monkeypatch)
+    text_processing_v2_5._load_japanese_tagger.cache_clear()
+    _block_import(monkeypatch, "fugashi")
+
+    with pytest.raises(RuntimeError, match="IndexTTS 2.5 Japanese preprocessing") as exc_info:
+        text_processing_v2_5._load_japanese_tagger()
+
+    assert INSTALL_COMMAND in str(exc_info.value)
+    text_processing_v2_5._load_japanese_tagger.cache_clear()
diff --git a/tests/utils/test_mm_outputs_partition.py b/tests/utils/test_mm_outputs_partition.py
index d70b95a79..09cd3960a 100644
--- a/tests/utils/test_mm_outputs_partition.py
+++ b/tests/utils/test_mm_outputs_partition.py
@@ -1,6 +1,7 @@
 import pytest
 import torch
 
+import vllm_omni.utils.mm_outputs as mm_outputs
 from vllm_omni.utils.mm_outputs import partition_flat_payload, partition_payload_list
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
@@ -69,3 +70,33 @@ def test_partition_duplex_audio_transcript_metadata_to_client_mm():
     assert "meta.turn_end" in client
     assert "meta.native_duplex_segment_text" not in client
     assert "meta.native_duplex_segment_text" in inter
+
+
+def test_snapshot_mm_payload_coalesces_compatible_tensor_list(monkeypatch):
+    chunks = [
+        torch.tensor([[7]], dtype=torch.long),
+        torch.empty(0, 1, dtype=torch.long),
+        torch.tensor([[9], [10]], dtype=torch.long),
+    ]
+    real_cat = torch.cat
+    cat_shapes = []
+
+    def recording_cat(tensors, *args, **kwargs):
+        cat_shapes.append([tuple(tensor.shape) for tensor in tensors])
+        return real_cat(tensors, *args, **kwargs)
+
+    monkeypatch.setattr(torch, "cat", recording_cat)
+
+    result = mm_outputs.snapshot_mm_payload({"codes.mel": chunks})
+
+    assert cat_shapes == [[(1, 1), (0, 1), (2, 1)]]
+    output_chunks = result["codes.mel"]
+    assert [tuple(chunk.shape) for chunk in output_chunks] == [
+        (1, 1),
+        (0, 1),
+        (2, 1),
+    ]
+    torch.testing.assert_close(output_chunks[0], chunks[0])
+    torch.testing.assert_close(output_chunks[1], chunks[1])
+    torch.testing.assert_close(output_chunks[2], chunks[2])
+    assert output_chunks[0].untyped_storage().data_ptr() == output_chunks[2].untyped_storage().data_ptr()
diff --git a/tests/worker/test_omni_gpu_model_runner.py b/tests/worker/test_omni_gpu_model_runner.py
index 949a2c7a8..ca282994a 100644
--- a/tests/worker/test_omni_gpu_model_runner.py
+++ b/tests/worker/test_omni_gpu_model_runner.py
@@ -5,6 +5,7 @@ import pytest
 import torch
 from vllm.v1.cudagraph_dispatcher import CUDAGraphMode
 
+from vllm_omni.worker.gpu_ar_model_runner import GPUARModelRunner
 from vllm_omni.worker.gpu_model_runner import (
     OmniGPUModelRunner,
     _filter_mrope_kwargs_for_model,
@@ -691,6 +692,49 @@ def test_full_payload_output_accumulation_hook_matrix():
         assert not runner._should_accumulate_full_payload_output()
 
 
+def _make_request_end_payload_runner(*, enabled=True, prefix_cache=None):
+    runner = object.__new__(GPUARModelRunner)
+    runner.model = SimpleNamespace(omni_payload_at_request_end=enabled)
+    runner.omni_prefix_cache = prefix_cache
+    runner.model_config = SimpleNamespace(
+        model_arch="IndexTTS25TalkerForConditionalGeneration",
+        model_stage="indextts2_5_talker",
+        async_chunk=False,
+        final_output=False,
+        custom_process_next_stage_input_func="module.full_payload",
+    )
+    runner._custom_process_func = object()
+    runner._pending_full_payload_send = {}
+    runner._stage_id = 0
+    runner._omni_connector = object()
+    return runner
+
+
+def test_request_end_payload_d2h_gate_requires_opt_in_and_no_prefix_cache():
+    assert _make_request_end_payload_runner()._should_defer_full_payload_d2h()
+    assert not _make_request_end_payload_runner(enabled=False)._should_defer_full_payload_d2h()
+    assert not _make_request_end_payload_runner(prefix_cache=object())._should_defer_full_payload_d2h()
+
+
+def test_request_end_payload_suppresses_per_step_multimodal_outputs():
+    runner = _make_request_end_payload_runner()
+
+    def unexpected_build(_payload):
+        raise AssertionError("request-end payloads must stay inside the GPU accumulator")
+
+    runner._build_multimodal_outputs = unexpected_build
+    pooler_inter = [{"codes.mel": torch.tensor([[7]])}]
+
+    inter_stage, client = runner._build_omni_step_outputs(
+        pooler_inter,
+        pooler_inter,
+        defer_full_payload_d2h=True,
+    )
+
+    assert inter_stage is None
+    assert client is None
+
+
 def test_sync_local_stage_payloads_retains_payload_until_request_is_active():
     runner = object.__new__(OmniGPUModelRunner)
     payload = {"codes": {"audio": [1, 2, 3]}}
diff --git a/vllm_omni/config/pipeline_registry.py b/vllm_omni/config/pipeline_registry.py
index d702f1ace..ac2e9d38d 100644
--- a/vllm_omni/config/pipeline_registry.py
+++ b/vllm_omni/config/pipeline_registry.py
@@ -61,7 +61,10 @@ from vllm_omni.model_executor.models.hunyuan_image3.pipeline import (
     HUNYUAN_IMAGE3_PIPELINE,
 )
 from vllm_omni.model_executor.models.hunyuan_video.pipeline import HUNYUAN_VIDEO_15_PIPELINE
-from vllm_omni.model_executor.models.indextts2.pipeline import INDEXTTS2_PIPELINE
+from vllm_omni.model_executor.models.indextts2.pipeline import (
+    INDEXTTS2_PIPELINE,
+    INDEXTTS25_PIPELINE,
+)
 from vllm_omni.model_executor.models.lance.pipeline import LANCE_PIPELINE
 from vllm_omni.model_executor.models.mammoth_moda2.pipeline import (
     MAMMOTH_MODA2_AR_PIPELINE,
@@ -164,6 +167,7 @@ OMNI_PIPELINES: dict[str, PipelineConfig | PipelineResolverFunc] = {
     "higgs_multimodal_qwen3": HIGGS_AUDIO_V3_PIPELINE,
     "dynin_omni": DYNIN_OMNI_PIPELINE,
     "indextts2": INDEXTTS2_PIPELINE,
+    "indextts2_5": INDEXTTS25_PIPELINE,
     "soulxsinger_svc": SOULXSINGER_SVC_PIPELINE,
     "soulxsinger_svs": SOULXSINGER_SVS_PIPELINE,
 }
diff --git a/vllm_omni/core/sched/omni_scheduling_coordinator.py b/vllm_omni/core/sched/omni_scheduling_coordinator.py
index 90820e51a..424fed2d9 100644
--- a/vllm_omni/core/sched/omni_scheduling_coordinator.py
+++ b/vllm_omni/core/sched/omni_scheduling_coordinator.py
@@ -57,9 +57,10 @@ _FULL_PAYLOAD_INPUT_STAGES: frozenset[tuple[str, str]] = frozenset(
         # audex TTA: tta thinker (Stage 0) -> XCodec1 (Stage 1, always sync
         # full-payload — CNN codec decoded over the full sequence).
         ("AudexXCodec1", "audex_xcodec"),
-        # indextts2: indextts2_talker (Stage 0) -> indextts2_s2mel_decoder
-        # (Stage 1). Stage 1 consumes the complete mel/latent payload.
+        # indextts2 / indextts2_5: talker (Stage 0) -> s2mel decoder
+        # (Stage 1). Stage 1 consumes the complete mel/optional-latent payload.
         ("IndexTTS2S2MelDecoder", "indextts2_s2mel_decoder"),
+        ("IndexTTS25S2MelDecoder", "indextts2_5_s2mel_decoder"),
         # dynin: token2text (Stage 0) -> token2image (Stage 1) ->
         # token2audio (Stage 2).  Producer wires via
         # custom_process_next_stage_input_func: *_full_payload in deploy yaml.
diff --git a/vllm_omni/deploy/indextts2_5.yaml b/vllm_omni/deploy/indextts2_5.yaml
new file mode 100644
index 000000000..3ea84e972
--- /dev/null
+++ b/vllm_omni/deploy/indextts2_5.yaml
@@ -0,0 +1,64 @@
+async_chunk: false
+trust_remote_code: true
+pipeline: indextts2_5
+connectors:
+  connector_of_shared_memory:
+    name: SharedMemoryConnector
+    extra:
+      codec_streaming: false
+      connector_get_sleep_s: 0.01
+      connector_get_max_wait_first_chunk: 5000
+      connector_get_max_wait: 500
+stages:
+  - stage_id: 0
+    max_num_seqs: 4
+    # Triton matches the native GPT-2 logits for this non-RoPE model.
+    # FlashInfer produces materially different semantic-token logits.
+    attention_backend: TRITON_ATTN
+    gpu_memory_utilization: 0.4
+    enable_prefix_caching: false
+    enable_chunked_prefill: false
+    skip_tokenizer_init: true
+    async_scheduling: true
+    max_num_batched_tokens: 2560
+    max_model_len: 2560
+    devices: "0"
+    output_connectors:
+      to_stage_1: connector_of_shared_memory
+    hf_overrides:
+      use_gpt_latent: false
+    # Stage 0 uses plain vLLM sampling, not the upstream default
+    # num_beams=3 beam search. Use upstream num_beams=1 for parity comparisons.
+    default_sampling_params:
+      temperature: 0.8
+      top_p: 0.8
+      top_k: 30
+      max_tokens: 1500
+      repetition_penalty: 10.0
+      stop_token_ids: [8193]
+      detokenize: false
+  - stage_id: 1
+    max_num_seqs: 4
+    gpu_memory_utilization: 0.4
+    enable_prefix_caching: false
+    skip_tokenizer_init: true
+    enforce_eager: true
+    async_scheduling: true
+    max_num_batched_tokens: 8192
+    max_model_len: 32768
+    devices: "0"
+    input_connectors:
+      from_stage_0: connector_of_shared_memory
+    hf_overrides:
+      use_gpt_latent: false
+      diffusion_steps: 25
+      s2mel_dit_bf16: true
+      s2mel_cfm_batch_size: 4
+      inference_cfg_rate: 0.7
+      s2mel_dit_cuda_graph: false
+      s2mel_dit_torch_compile: true
+      s2mel_dit_torch_compile_mode: default
+      s2mel_vocoder_torch_compile: false
+    default_sampling_params:
+      temperature: 0.0
+      max_tokens: 32767
diff --git a/vllm_omni/deploy/qwen2_5_omni.yaml b/vllm_omni/deploy/qwen2_5_omni.yaml
index 487ceefdd..1c1bed624 100644
--- a/vllm_omni/deploy/qwen2_5_omni.yaml
+++ b/vllm_omni/deploy/qwen2_5_omni.yaml
@@ -13,8 +13,8 @@
 #     the custom generation loop — set explicitly everywhere).
 #   * AR stages (thinker, talker):   model-dependent. Qwen2.5-Omni runs eager
 #     on CUDA (thinker uses custom ops that don't trace cleanly); NPU / XPU
-#     platform overrides flip back to false where cudagraph is verified.
-#     Qwen3-Omni / Qwen3-TTS AR stages use the default (false = cudagraph on).
+#     overrides are documented below. Qwen3-Omni / Qwen3-TTS AR stages use the
+#     default (false = cudagraph on).
 async_chunk: false
 
 stages:
@@ -82,13 +82,15 @@ platforms:
 
   xpu:
     stages:
-      # Verified on 2x Intel Arc Pro B60. Both AR stages use cudagraphs.
+      # PyTorch 2.13 XPU Dynamo raises duplicate-handler assertions while
+      # compiling both Qwen2.5 AR stages. Keep them eager until that toolchain
+      # issue is fixed; stage 2 already inherits enforce_eager: true above.
       - stage_id: 0
         gpu_memory_utilization: 0.9
-        enforce_eager: false
+        enforce_eager: true
       - stage_id: 1
         gpu_memory_utilization: 0.5
-        enforce_eager: false
+        enforce_eager: true
       - stage_id: 2
         gpu_memory_utilization: 0.3
         # Stage 2 colocates with stage 1's device on XPU.
diff --git a/vllm_omni/engine/arg_utils.py b/vllm_omni/engine/arg_utils.py
index c1512de99..a66f39ce3 100644
--- a/vllm_omni/engine/arg_utils.py
+++ b/vllm_omni/engine/arg_utils.py
@@ -22,6 +22,8 @@ _ARCH_TO_MODEL_TYPE: dict[str, str] = {
     "GLMTTSForConditionalGeneration": "glm_tts",
     "IndexTTS2S2MelDecoder": "indextts2",
     "IndexTTS2TalkerForConditionalGeneration": "indextts2",
+    "IndexTTS25S2MelDecoder": "indextts2_5",
+    "IndexTTS25TalkerForConditionalGeneration": "indextts2_5",
     "OmniVoiceModel": "omnivoice",
     # PersonaPlex ships an empty config.json, so create_model_config() must patch
     # model_type=personaplex from the arch name or the staged pipeline can't load
@@ -44,6 +46,7 @@ def _register_omni_hf_configs() -> None:
 
         from vllm_omni.model_executor.models.indextts2.configuration_indextts2 import (
             IndexTTS2Config,
+            IndexTTS25Config,
         )
         from vllm_omni.model_executor.models.ming_tts.config_ming_tts import (
             MingDenseConfig,
@@ -79,6 +82,7 @@ def _register_omni_hf_configs() -> None:
         ("dense", MingDenseConfig),
         ("bailingmm", MingMoeConfig),
         ("indextts2", IndexTTS2Config),
+        ("indextts2_5", IndexTTS25Config),
         ("moss_tts_local", MossTTSLocalConfig),
         ("moss_tts_realtime", MossTTSRealtimeConfig),
         ("qwen3_tts", Qwen3TTSConfig),
@@ -250,7 +254,15 @@ class OmniEngineArgs(EngineArgs):
             if config_dict.get("model_type"):
                 return  # config.json already has model_type, no patching needed
         except Exception:
-            return  # can't load config, let vLLM handle the error
+            # The official IndexTTS 2.5 bundle has no HuggingFace config.json.
+            # Keep this exception model-scoped so other loader failures retain
+            # vLLM's normal error path.
+            if model_type != "indextts2_5" or not os.path.isdir(self.model):
+                return
+            config_path = os.path.join(self.model, "config.json")
+            if os.path.lexists(config_path):
+                return
+            config_dict = {}
 
         # Create a temp dir with a patched config.json
         temp_dir = tempfile.mkdtemp(prefix="omni_hf_config_")
diff --git a/vllm_omni/engine/stage_init_utils.py b/vllm_omni/engine/stage_init_utils.py
index e8284ba68..b0a95d22c 100644
--- a/vllm_omni/engine/stage_init_utils.py
+++ b/vllm_omni/engine/stage_init_utils.py
@@ -20,6 +20,7 @@ from dataclasses import dataclass, fields, replace
 from typing import Any, Literal, cast
 
 from vllm.logger import init_logger
+from vllm.renderers import BaseRenderer
 from vllm.sampling_params import SamplingParams
 from vllm.tokenizers import cached_tokenizer_from_config
 from vllm.usage.usage_lib import UsageContext
@@ -1119,11 +1120,30 @@ def build_llm_stage_output_processor(
     )
 
 
+class _TokenOnlyRenderer(BaseRenderer):
+    """Renderer for stages that explicitly skip tokenizer initialization."""
+
+    def render_messages(self, messages, params):
+        raise ValueError(
+            "Chat messages are unavailable when skip_tokenizer_init=True; submit prompt_token_ids or prompt_embeds"
+        )
+
+
+def _build_token_only_renderer(stage_vllm_config: Any) -> BaseRenderer:
+    return _TokenOnlyRenderer(stage_vllm_config, tokenizer=None)
+
+
 def build_stage0_input_processor(stage_vllm_config: Any) -> InputProcessor:
     """Build the shared stage-0 input processor."""
 
     patch_generation_config_if_needed(stage_vllm_config.model_config)
-    input_processor = InputProcessor(vllm_config=stage_vllm_config)
+    if bool(getattr(stage_vllm_config.model_config, "skip_tokenizer_init", False)):
+        input_processor = InputProcessor(
+            vllm_config=stage_vllm_config,
+            renderer=_build_token_only_renderer(stage_vllm_config),
+        )
+    else:
+        input_processor = InputProcessor(vllm_config=stage_vllm_config)
     input_processor.input_preprocessor = OmniInputPreprocessor(
         vllm_config=stage_vllm_config,
         renderer=input_processor.renderer,
diff --git a/vllm_omni/entrypoints/openai/api_server.py b/vllm_omni/entrypoints/openai/api_server.py
index 100eb69ee..940f62f2e 100755
--- a/vllm_omni/entrypoints/openai/api_server.py
+++ b/vllm_omni/entrypoints/openai/api_server.py
@@ -996,9 +996,11 @@ async def omni_init_app_state(
     )
 
     # Warm up chat template processing to avoid first-request latency
-    # Upstream f5ffc59b6a removed OpenAIServingChat.warmup() and moved the
-    # warmup onto the renderer (OnlineRenderer.warmup()); mirror upstream.
-    state.online_renderer.warmup()
+    # Upstream f5ffc59b6a moved warmup onto OnlineRenderer. Accelerator
+    # images can temporarily lag that renderer API, where warmup is optional.
+    renderer_warmup = getattr(state.online_renderer, "warmup", None)
+    if renderer_warmup is not None:
+        renderer_warmup()
 
     state.openai_serving_completion = (
         OpenAIServingCompletion(
diff --git a/vllm_omni/entrypoints/openai/protocol/audio.py b/vllm_omni/entrypoints/openai/protocol/audio.py
index 92b2efd14..1564c4523 100644
--- a/vllm_omni/entrypoints/openai/protocol/audio.py
+++ b/vllm_omni/entrypoints/openai/protocol/audio.py
@@ -82,7 +82,8 @@ class OpenAICreateSpeechRequest(BaseModel):
         description=(
             "Streaming switch; defaults to OpenAI speech.audio.* SSE events. "
             "Set stream_format='audio' to opt into raw pcm/wav byte streaming. "
-            "Requires response_format='pcm' or 'wav'. Speed adjustment is not supported when streaming."
+            "HTTP streaming requires response_format='pcm' or 'wav'. "
+            "Models with native speed control may accept speed adjustment over HTTP."
         ),
     )
 
@@ -317,8 +318,6 @@ class OpenAICreateSpeechRequest(BaseModel):
                 )
             if self.speed is None:
                 self.speed = 1.0
-            elif self.speed != 1.0:
-                raise ValueError("Speed adjustment is not supported when streaming. Set speed=1.0 or omit it.")
         return self
 
 
@@ -532,7 +531,8 @@ class StreamingSpeechSessionConfig(BaseModel):
         default=False,
         description=(
             "If true, send raw PCM audio chunks progressively over WebSocket. "
-            "Requires response_format='pcm'. Speed adjustment is not supported when streaming."
+            "Requires response_format='pcm'. WebSocket streaming currently requires "
+            "speed=1.0, including for models with native speed control."
         ),
     )
     word_timestamps: bool = Field(
@@ -556,5 +556,8 @@ class StreamingSpeechSessionConfig(BaseModel):
             if self.speed is None:
                 self.speed = 1.0
             elif self.speed != 1.0:
-                raise ValueError("Speed adjustment is not supported when stream_audio=true. Set speed=1.0 or omit it.")
+                raise ValueError(
+                    "WebSocket stream_audio=true currently requires speed=1.0; "
+                    "native speed control is only available through HTTP streaming."
+                )
         return self
diff --git a/vllm_omni/entrypoints/openai/serving_chat.py b/vllm_omni/entrypoints/openai/serving_chat.py
index ebc417615..ce019a970 100755
--- a/vllm_omni/entrypoints/openai/serving_chat.py
+++ b/vllm_omni/entrypoints/openai/serving_chat.py
@@ -83,7 +83,14 @@ from vllm.inputs import PromptType
 from vllm.logger import init_logger
 from vllm.multimodal.media.connector import MediaConnector
 from vllm.outputs import RequestOutput
-from vllm.parser.mistral import MistralToolCall
+
+try:
+    from vllm.parser.mistral import MistralToolCall
+except ImportError:
+    # Accelerator images can lag the core vLLM release by one version.
+    from vllm.tool_parsers.mistral_tool_parser import MistralToolCall
+
+
 from vllm.reasoning import ReasoningParser
 from vllm.renderers import BaseRenderer, merge_kwargs
 from vllm.renderers.inputs import TokPrompt
diff --git a/vllm_omni/entrypoints/openai/serving_speech.py b/vllm_omni/entrypoints/openai/serving_speech.py
index 288625dfe..6b7ca1318 100644
--- a/vllm_omni/entrypoints/openai/serving_speech.py
+++ b/vllm_omni/entrypoints/openai/serving_speech.py
@@ -101,6 +101,7 @@ _SAMPLING_MAX_TOKENS_TTS_MODEL_TYPES = {
     "higgs_audio_v2",
     "higgs_audio_v3",
     "indextts2",
+    "indextts2_5",
     "audex",
     "audex_tta",
 }
@@ -513,6 +514,15 @@ class OmniOpenAIServingSpeech(OpenAIServing, AudioMixin):
             self._adapter = adapter_cls(ctx)
         return self._adapter
 
+    def _uses_native_speed_control(self) -> bool:
+        adapter = self._get_tts_adapter()
+        return bool(adapter is not None and adapter.native_speed_control)
+
+    def _audio_encode_speed(self, request: OpenAICreateSpeechRequest) -> float:
+        if self._uses_native_speed_control():
+            return 1.0
+        return float(request.speed or 1.0)
+
     async def warmup(self) -> None:
         """Run a synthetic speech request to trigger all first-request warmup.
 
@@ -3473,7 +3483,7 @@ class OmniOpenAIServingSpeech(OpenAIServing, AudioMixin):
                 audio_tensor=audio_tensor,
                 sample_rate=sample_rate,
                 response_format=request.response_format or "wav",
-                speed=request.speed or 1.0,
+                speed=self._audio_encode_speed(request),
                 base64_encode=base64_encode,
             )
             audio_response: AudioResponse = self.create_audio(audio_obj)
@@ -3587,7 +3597,7 @@ class OmniOpenAIServingSpeech(OpenAIServing, AudioMixin):
                 audio_tensor=audio_tensor,
                 sample_rate=sample_rate,
                 response_format=request.response_format or "wav",
-                speed=request.speed or 1.0,
+                speed=self._audio_encode_speed(request),
                 base64_encode=False,
             )
             audio_response: AudioResponse = self.create_audio(audio_obj)
@@ -3629,7 +3639,7 @@ class OmniOpenAIServingSpeech(OpenAIServing, AudioMixin):
             return response_format, self.create_error_response(
                 f"{mode_label} is only supported for 'pcm' and 'wav' formats. Got '{response_format}'."
             )
-        if request.speed is not None and request.speed != 1.0:
+        if request.speed is not None and request.speed != 1.0 and not self._uses_native_speed_control():
             return response_format, self.create_error_response(
                 f"{mode_label} is not supported with speed adjustment. "
                 "Use a non-streaming request or remove the speed parameter."
diff --git a/vllm_omni/entrypoints/openai/tts_adapters/base.py b/vllm_omni/entrypoints/openai/tts_adapters/base.py
index 69d6c5c6e..b8679041c 100644
--- a/vllm_omni/entrypoints/openai/tts_adapters/base.py
+++ b/vllm_omni/entrypoints/openai/tts_adapters/base.py
@@ -115,6 +115,8 @@ class TTSModelAdapter(ABC):
     detect_priority: ClassVar[int] = 100
     #: Serving backend: ``"ar"`` (engine_client) or ``"diffusion"``.
     backend: ClassVar[str] = "ar"
+    #: Whether the model consumes ``request.speed`` in its native parameters.
+    native_speed_control: ClassVar[bool] = False
 
     max_new_tokens_min = 1
 
diff --git a/vllm_omni/entrypoints/openai/tts_adapters/indextts2.py b/vllm_omni/entrypoints/openai/tts_adapters/indextts2.py
index 641e380da..d1cb2a469 100644
--- a/vllm_omni/entrypoints/openai/tts_adapters/indextts2.py
+++ b/vllm_omni/entrypoints/openai/tts_adapters/indextts2.py
@@ -6,7 +6,7 @@ from __future__ import annotations
 import hashlib
 import math
 from collections.abc import Mapping
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, ClassVar
 
 import numpy as np
 import torch
@@ -15,6 +15,10 @@ from vllm.utils import random_uuid
 
 from vllm_omni.entrypoints.openai.tts_adapters import register_tts_adapter
 from vllm_omni.entrypoints.openai.tts_adapters.base import ARTTSAdapter, PreparedRequest
+from vllm_omni.model_executor.models.indextts2.configuration_indextts2 import (
+    INDEXTTS25_MAX_DURATION_FACTOR,
+    INDEXTTS25_MIN_DURATION_FACTOR,
+)
 
 if TYPE_CHECKING:
     from vllm_omni.entrypoints.openai.protocol.audio import OpenAICreateSpeechRequest
@@ -102,6 +106,8 @@ def indextts2_conditioning_cache_salt(
         "emo_text",
         "use_emo_text",
         "use_random",
+        "lang",
+        "text_normalization",
     ):
         h.update(b"\x00")
         h.update(key.encode("utf-8"))
@@ -206,14 +212,34 @@ class IndexTTS2Adapter(ARTTSAdapter):
             estimate_indextts2_prefill_prompt_len,
         )
 
+        prompt_kwargs: dict[str, Any] = {}
+        if self.name == "indextts2_5":
+            from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+                INDEXTTS25_TOKENIZER_FILE,
+            )
+
+            hf_config = getattr(server.engine_client.model_config, "hf_config", None)
+            prompt_kwargs["tokenizer_file"] = getattr(
+                hf_config,
+                "tokenizer_file",
+                INDEXTTS25_TOKENIZER_FILE,
+            )
         ph_len = estimate_indextts2_prefill_prompt_len(
             server.engine_client.model_config.model,
             request.input,
+            model_type=self.name,
+            lang=str(_first_conditioning_value(tts_params.get("lang")) or "zh"),
+            text_normalization=bool(
+                _first_conditioning_value(tts_params.get("text_normalization"))
+                if "text_normalization" in tts_params
+                else True
+            ),
+            **prompt_kwargs,
         )
         prompt = tokens_input(prompt_token_ids=[1] * ph_len)
         prompt["additional_information"] = tts_params
         prompt["cache_salt"] = indextts2_conditioning_cache_salt(request, tts_params)
-        return PreparedRequest(prompt=prompt, tts_params=tts_params, model_type="indextts2")
+        return PreparedRequest(prompt=prompt, tts_params=tts_params, model_type=self.name)
 
     async def _build_params(self, request: OpenAICreateSpeechRequest) -> dict[str, Any]:
         server = self.ctx.server
@@ -241,3 +267,59 @@ class IndexTTS2Adapter(ARTTSAdapter):
             else:
                 params[key] = [extras[key]]
         return params
+
+
+@register_tts_adapter
+class IndexTTS25Adapter(IndexTTS2Adapter):
+    stage_keys = frozenset({"indextts2_5_talker"})
+    name = "indextts2_5"
+    native_speed_control: ClassVar[bool] = True
+
+    def validate(self, request: OpenAICreateSpeechRequest) -> str | None:
+        error = super().validate(request)
+        if error is not None:
+            return error
+        speed = request.speed if request.speed is not None else 1.0
+        if speed < INDEXTTS25_MIN_DURATION_FACTOR or speed > INDEXTTS25_MAX_DURATION_FACTOR:
+            return "IndexTTS 2.5 speed must be between 0.5 and 2.0"
+        return None
+
+    def _validate_extra_params(self, extras: Mapping[str, Any]) -> str | None:
+        error = super()._validate_extra_params(extras)
+        if error is not None:
+            return error
+
+        if "lang" in extras:
+            value = extras["lang"]
+            if not isinstance(value, str):
+                return "extra_params.lang must be a string"
+            from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+                normalize_language_code,
+            )
+
+            try:
+                normalize_language_code(value)
+            except ValueError as exc:
+                return str(exc)
+        if "text_normalization" in extras and not isinstance(
+            extras["text_normalization"],
+            bool,
+        ):
+            return "extra_params.text_normalization must be a boolean"
+        return None
+
+    async def _build_params(
+        self,
+        request: OpenAICreateSpeechRequest,
+    ) -> dict[str, Any]:
+        params = await super()._build_params(request)
+        extras = request.extra_params if isinstance(request.extra_params, dict) else {}
+        from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+            normalize_language_code,
+        )
+
+        params["lang"] = [normalize_language_code(str(extras.get("lang", "zh")))]
+        params["text_normalization"] = [bool(extras.get("text_normalization", True))]
+        speed = request.speed if request.speed is not None else 1.0
+        params["duration_factor"] = [1.0 / speed]
+        return params
diff --git a/vllm_omni/model_executor/models/common/qwen3_code_predictor.py b/vllm_omni/model_executor/models/common/qwen3_code_predictor.py
index 1bea2a124..8c9c134cf 100644
--- a/vllm_omni/model_executor/models/common/qwen3_code_predictor.py
+++ b/vllm_omni/model_executor/models/common/qwen3_code_predictor.py
@@ -571,7 +571,10 @@ class CodePredictorWrapper(nn.Module):
         self._lm_heads_list = list(self.lm_head)
         self._codec_embeds_list = list(self.model.codec_embedding)
 
-        if not current_omni_platform.supports_torch_inductor():
+        # Torch 2.13 XPU Dynamo can double-register built-in handlers when
+        # spawned workers compile this predictor. Keep this narrow path eager
+        # until the upstream XPU compiler issue is resolved.
+        if current_omni_platform.is_xpu() or not current_omni_platform.supports_torch_inductor():
             # NPU or other platforms without Inductor support
             self._compiled_model_fwd = self.model.forward
 
diff --git a/vllm_omni/model_executor/models/indextts2/codec/__init__.py b/vllm_omni/model_executor/models/indextts2/codec/__init__.py
new file mode 100644
index 000000000..55c98dcb9
--- /dev/null
+++ b/vllm_omni/model_executor/models/indextts2/codec/__init__.py
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Copyright contributors to the Amphion project
+"""Inference-only EnhancedCodec runtime for IndexTTS 2.5."""
+
+from .models import EnhancedCodec
+
+__all__ = ["EnhancedCodec"]
diff --git a/vllm_omni/model_executor/models/indextts2/codec/models.py b/vllm_omni/model_executor/models/indextts2/codec/models.py
new file mode 100644
index 000000000..d88534ab8
--- /dev/null
+++ b/vllm_omni/model_executor/models/indextts2/codec/models.py
@@ -0,0 +1,138 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Copyright contributors to the Amphion project
+"""Inference-only EnhancedCodec decoder for IndexTTS 2.5.
+
+The checkpoint originates from the Amphion EnhancedCodec implementation
+vendored by IndexTTS 2.5. The encoder and training paths are deliberately not
+constructed because vLLM-Omni only performs semantic-code decoding here.
+"""
+
+from __future__ import annotations
+
+import logging
+from collections.abc import Mapping
+from pathlib import Path
+from typing import Any
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from .quantizer import ResidualVQDecoder
+from .vocos import VocosBackbone
+
+logger = logging.getLogger(__name__)
+
+
+def _config_value(
+    cfg: Mapping[str, Any] | Any | None,
+    name: str,
+    default: Any,
+) -> Any:
+    if cfg is None:
+        return default
+    if isinstance(cfg, Mapping):
+        return cfg.get(name, default)
+    return getattr(cfg, name, default)
+
+
+class EnhancedCodec(nn.Module):
+    """Subset of EnhancedCodec required for ``decode(codes)``."""
+
+    def __init__(
+        self,
+        codebook_size: int = 8192,
+        hidden_size: int = 1024,
+        codebook_dim: int = 8,
+        vocos_dim: int = 384,
+        vocos_intermediate_dim: int = 2048,
+        vocos_num_layers: int = 12,
+        num_quantizers: int = 1,
+        downsample_scale: int | None = 2,
+        cfg: Mapping[str, Any] | Any | None = None,
+    ):
+        super().__init__()
+        codebook_size = int(_config_value(cfg, "codebook_size", codebook_size))
+        hidden_size = int(_config_value(cfg, "hidden_size", hidden_size))
+        codebook_dim = int(_config_value(cfg, "codebook_dim", codebook_dim))
+        vocos_dim = int(_config_value(cfg, "vocos_dim", vocos_dim))
+        vocos_intermediate_dim = int(_config_value(cfg, "vocos_intermediate_dim", vocos_intermediate_dim))
+        vocos_num_layers = int(_config_value(cfg, "vocos_num_layers", vocos_num_layers))
+        num_quantizers = int(_config_value(cfg, "num_quantizers", num_quantizers))
+        downsample_scale = _config_value(
+            cfg,
+            "downsample_scale",
+            downsample_scale,
+        )
+
+        self.hidden_size = hidden_size
+        self.num_quantizers = num_quantizers
+        self.downsample_scale = downsample_scale
+        self.decoder = nn.Sequential(
+            VocosBackbone(
+                input_channels=hidden_size,
+                dim=vocos_dim,
+                intermediate_dim=vocos_intermediate_dim,
+                num_layers=vocos_num_layers,
+            ),
+            nn.Linear(vocos_dim, hidden_size),
+        )
+        self.quantizer = ResidualVQDecoder(
+            input_dim=hidden_size,
+            num_quantizers=num_quantizers,
+            codebook_size=codebook_size,
+            codebook_dim=codebook_dim,
+        )
+        if downsample_scale is not None and downsample_scale > 1:
+            self.up = nn.Conv1d(
+                hidden_size,
+                hidden_size,
+                kernel_size=3,
+                stride=1,
+                padding=1,
+            )
+
+    def decode(self, codes: torch.Tensor) -> torch.Tensor:
+        """Decode `[B,T]` or `[N,B,T]` codes to `[B,T*scale,hidden]`."""
+        if codes.ndim == 2:
+            codes = codes.unsqueeze(0)
+        if codes.ndim != 3:
+            raise ValueError(f"EnhancedCodec codes must have shape [B,T] or [N,B,T], got {tuple(codes.shape)}")
+        if codes.shape[0] != self.num_quantizers:
+            raise ValueError(f"EnhancedCodec expected {self.num_quantizers} codebooks, got {codes.shape[0]}")
+
+        hidden = self.quantizer.vq2emb(codes)
+        hidden = self.decoder(hidden)
+        if self.downsample_scale is not None and self.downsample_scale > 1:
+            hidden = hidden.transpose(1, 2)
+            hidden = F.interpolate(
+                hidden,
+                scale_factor=self.downsample_scale,
+                mode="nearest",
+            )
+            hidden = self.up(hidden).transpose(1, 2)
+        return hidden
+
+    def load_checkpoint(self, checkpoint_path: str) -> None:
+        path = Path(checkpoint_path)
+        if not path.is_file():
+            raise FileNotFoundError(f"EnhancedCodec checkpoint not found: {path}")
+        checkpoint = torch.load(path, map_location="cpu", weights_only=True)
+        saved_state = checkpoint.get("model", checkpoint)
+        own_state = self.state_dict()
+        missing = [
+            name
+            for name, value in own_state.items()
+            if name not in saved_state or saved_state[name].shape != value.shape
+        ]
+        if missing:
+            raise RuntimeError("EnhancedCodec checkpoint is missing required decoder weights: " + ", ".join(missing))
+        self.load_state_dict(
+            {name: saved_state[name] for name in own_state},
+            strict=True,
+        )
+        logger.info(
+            "Loaded %d inference-only EnhancedCodec tensors from %s",
+            len(own_state),
+            path,
+        )
diff --git a/vllm_omni/model_executor/models/indextts2/codec/quantizer.py b/vllm_omni/model_executor/models/indextts2/codec/quantizer.py
new file mode 100644
index 000000000..f5c44ee94
--- /dev/null
+++ b/vllm_omni/model_executor/models/indextts2/codec/quantizer.py
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Copyright contributors to the Amphion project
+"""Decode-only factorized residual vector quantizer.
+
+Adapted from the Amphion codec implementation vendored by IndexTTS 2.5.
+Training-only paths are intentionally omitted.
+"""
+
+from __future__ import annotations
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from torch.nn.utils import weight_norm
+
+
+def _weight_norm_conv1d(*args, **kwargs) -> nn.Conv1d:
+    return weight_norm(nn.Conv1d(*args, **kwargs))
+
+
+class FactorizedVectorQuantizeDecoder(nn.Module):
+    def __init__(
+        self,
+        *,
+        input_dim: int,
+        codebook_size: int,
+        codebook_dim: int,
+    ):
+        super().__init__()
+        self.input_dim = input_dim
+        self.codebook_dim = codebook_dim
+        if input_dim != codebook_dim:
+            # Keep upstream module names and weight-normalized parameter layout
+            # so codec.pth keys load without conversion.
+            self.in_project = _weight_norm_conv1d(
+                input_dim,
+                codebook_dim,
+                kernel_size=1,
+            )
+            self.out_project = _weight_norm_conv1d(
+                codebook_dim,
+                input_dim,
+                kernel_size=1,
+            )
+        else:
+            self.in_project = nn.Identity()
+            self.out_project = nn.Identity()
+        self.codebook = nn.Embedding(codebook_size, codebook_dim)
+
+    def vq2emb(self, codes: torch.Tensor) -> torch.Tensor:
+        embedding = F.embedding(codes, self.codebook.weight).transpose(1, 2)
+        return self.out_project(embedding)
+
+
+class ResidualVQDecoder(nn.Module):
+    def __init__(
+        self,
+        *,
+        input_dim: int,
+        num_quantizers: int,
+        codebook_size: int,
+        codebook_dim: int,
+    ):
+        super().__init__()
+        self.num_quantizers = num_quantizers
+        self.quantizers = nn.ModuleList(
+            [
+                FactorizedVectorQuantizeDecoder(
+                    input_dim=input_dim,
+                    codebook_size=codebook_size,
+                    codebook_dim=codebook_dim,
+                )
+                for _ in range(num_quantizers)
+            ]
+        )
+
+    def vq2emb(
+        self,
+        codes: torch.Tensor,
+        n_quantizers: int | None = None,
+    ) -> torch.Tensor:
+        count = self.num_quantizers if n_quantizers is None else n_quantizers
+        quantized: torch.Tensor | None = None
+        for index, quantizer in enumerate(self.quantizers):
+            if index >= count:
+                break
+            value = quantizer.vq2emb(codes[index])
+            quantized = value if quantized is None else quantized + value
+        if quantized is None:
+            raise ValueError("EnhancedCodec requires at least one quantizer")
+        return quantized
diff --git a/vllm_omni/model_executor/models/indextts2/codec/vocos.py b/vllm_omni/model_executor/models/indextts2/codec/vocos.py
new file mode 100644
index 000000000..7100cb9e6
--- /dev/null
+++ b/vllm_omni/model_executor/models/indextts2/codec/vocos.py
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: Copyright contributors to the Amphion project
+"""ConvNeXt Vocos backbone used by the IndexTTS 2.5 codec decoder."""
+
+from __future__ import annotations
+
+import torch
+import torch.nn as nn
+
+
+class ConvNeXtBlock(nn.Module):
+    def __init__(
+        self,
+        *,
+        dim: int,
+        intermediate_dim: int,
+        layer_scale_init_value: float,
+    ):
+        super().__init__()
+        self.dwconv = nn.Conv1d(
+            dim,
+            dim,
+            kernel_size=7,
+            padding=3,
+            groups=dim,
+        )
+        self.norm = nn.LayerNorm(dim, eps=1e-6)
+        self.pwconv1 = nn.Linear(dim, intermediate_dim)
+        self.act = nn.GELU()
+        self.pwconv2 = nn.Linear(intermediate_dim, dim)
+        self.gamma = nn.Parameter(
+            layer_scale_init_value * torch.ones(dim),
+            requires_grad=True,
+        )
+
+    def forward(self, inputs: torch.Tensor) -> torch.Tensor:
+        residual = inputs
+        hidden = self.dwconv(inputs).transpose(1, 2)
+        hidden = self.norm(hidden)
+        hidden = self.pwconv1(hidden)
+        hidden = self.act(hidden)
+        hidden = self.pwconv2(hidden)
+        hidden = self.gamma * hidden
+        return residual + hidden.transpose(1, 2)
+
+
+class VocosBackbone(nn.Module):
+    def __init__(
+        self,
+        *,
+        input_channels: int,
+        dim: int,
+        intermediate_dim: int,
+        num_layers: int,
+    ):
+        super().__init__()
+        self.embed = nn.Conv1d(
+            input_channels,
+            dim,
+            kernel_size=7,
+            padding=3,
+        )
+        self.norm = nn.LayerNorm(dim, eps=1e-6)
+        layer_scale = 1 / num_layers
+        self.convnext = nn.ModuleList(
+            [
+                ConvNeXtBlock(
+                    dim=dim,
+                    intermediate_dim=intermediate_dim,
+                    layer_scale_init_value=layer_scale,
+                )
+                for _ in range(num_layers)
+            ]
+        )
+        self.final_layer_norm = nn.LayerNorm(dim, eps=1e-6)
+
+    def forward(self, inputs: torch.Tensor) -> torch.Tensor:
+        hidden = self.embed(inputs)
+        hidden = self.norm(hidden.transpose(1, 2)).transpose(1, 2)
+        for block in self.convnext:
+            hidden = block(hidden)
+        return self.final_layer_norm(hidden.transpose(1, 2))
diff --git a/vllm_omni/model_executor/models/indextts2/configuration_indextts2.py b/vllm_omni/model_executor/models/indextts2/configuration_indextts2.py
index 504923b1a..e39a34cc3 100644
--- a/vllm_omni/model_executor/models/indextts2/configuration_indextts2.py
+++ b/vllm_omni/model_executor/models/indextts2/configuration_indextts2.py
@@ -5,6 +5,9 @@ import copy
 
 from transformers import PretrainedConfig
 
+INDEXTTS25_MIN_DURATION_FACTOR = 0.5
+INDEXTTS25_MAX_DURATION_FACTOR = 2.0
+
 
 class IndexTTS2Config(PretrainedConfig):
     model_type = "indextts2"
@@ -138,6 +141,10 @@ class IndexTTS2Config(PretrainedConfig):
         "emo_num": [3, 17, 2, 8, 4, 5, 10, 24],
         "qwen_emo_path": "qwen0.6bemo4-merge/",
         "vocoder": {"type": "bigvgan", "name": "nvidia/bigvgan_v2_22khz_80band_256x"},
+        "tokenizer_file": "bpe.model",
+        "semantic_codec_checkpoint": "semantic_codec.pth",
+        "semantic_codec_type": "repcodec",
+        "use_gpt_latent": True,
         "version": 2.0,
         # Default-off performance tracing for IndexTTS2 overhead analysis.
     }
@@ -148,9 +155,49 @@ class IndexTTS2Config(PretrainedConfig):
         for attr, default in defaults.items():
             if not hasattr(self, attr):
                 setattr(self, attr, default)
+        # vLLM kernel warmup reads the top-level vocabulary size even when
+        # tokenizer initialization is skipped for the audio-code model.
+        self.vocab_size = int(getattr(self, "vocab_size", 0) or self.gpt["number_mel_codes"])
         # Keep gpt.model_dim in sync with top-level hidden_size.
         if isinstance(self.gpt, dict) and self.gpt.get("model_dim") != self.hidden_size:
             self.gpt["model_dim"] = self.hidden_size
         self.output_sample_rate = int(
             self.s2mel["preprocess_params"].get("sr", 22050) if isinstance(self.s2mel, dict) else 22050
         )
+
+
+class IndexTTS25Config(IndexTTS2Config):
+    """Configuration for the official IndexTTS 2.5 checkpoint.
+
+    IndexTTS 2.5 keeps the GPT/S2Mel backbone shapes used by IndexTTS 2,
+    but switches text tokenization and speaker conditioning, and decodes
+    semantic codes with EnhancedCodec. GPT latent conditioning is disabled by
+    default upstream; the opt-in path is an experimental vLLM-Omni-specific
+    latent variant with no official runnable reference output.
+    """
+
+    model_type = "indextts2_5"
+    _DEFAULTS = copy.deepcopy(IndexTTS2Config._DEFAULTS)
+    _DEFAULTS["gpt"] = {
+        **_DEFAULTS["gpt"],
+        "number_text_tokens": 60509,
+    }
+    _DEFAULTS.update(
+        {
+            "tokenizer_file": "multilingual_zh_ja_yue_char_del.tiktoken",
+            "semantic_codec_checkpoint": "codec.pth",
+            "semantic_codec_type": "enhanced",
+            "use_gpt_latent": False,
+            "version": 2.5,
+        }
+    )
+
+    def __init__(self, **kwargs):
+        # HF overrides are sometimes intentionally partial. Merge nested GPT
+        # values with the 2.5 defaults so dimensions needed by the shared
+        # implementation remain present while explicit values still win.
+        explicit_gpt = kwargs.pop("gpt", None)
+        merged_gpt = copy.deepcopy(self._DEFAULTS["gpt"])
+        if explicit_gpt is not None:
+            merged_gpt.update(explicit_gpt)
+        super().__init__(gpt=merged_gpt, **kwargs)
diff --git a/vllm_omni/model_executor/models/indextts2/dit_cuda_graph.py b/vllm_omni/model_executor/models/indextts2/dit_cuda_graph.py
index 4d32b8c1b..8b75ebfa8 100644
--- a/vllm_omni/model_executor/models/indextts2/dit_cuda_graph.py
+++ b/vllm_omni/model_executor/models/indextts2/dit_cuda_graph.py
@@ -51,6 +51,41 @@ class CUDAGraphDiTRunner:
         self.enabled = bool(enabled)
         self._cache: OrderedDict[tuple, _GraphEntry] = OrderedDict()
         self.last_call_info: dict[str, object] = {}
+        self._stats = {
+            "calls": 0,
+            "hits": 0,
+            "captures": 0,
+            "capture_failures": 0,
+            "evictions": 0,
+            "eager": 0,
+        }
+
+    def stats_snapshot(self) -> dict[str, object]:
+        """Return bounded cumulative graph-cache telemetry."""
+        return {
+            **self._stats,
+            "cache_size": len(self._cache),
+        }
+
+    def _replay(
+        self,
+        entry: _GraphEntry,
+        *,
+        x_in: torch.Tensor,
+        c: torch.Tensor,
+    ) -> torch.Tensor:
+        """Replay with only the inputs that vary between Euler steps.
+
+        ``input_pos`` is the same arange slice for a given cache key and the
+        runner is enabled only for all-True masks, so their capture-time
+        buffers remain valid.  The returned output is also the graph's static
+        buffer: all downstream consumers are enqueued on the same CUDA stream
+        before the next replay can overwrite it.
+        """
+        entry.static_x.copy_(x_in)
+        entry.static_c.copy_(c)
+        entry.graph.replay()
+        return entry.static_out
 
     def __call__(
         self,
@@ -59,7 +94,9 @@ class CUDAGraphDiTRunner:
         input_pos: torch.Tensor,
         mask: torch.Tensor | None,
     ) -> torch.Tensor:
+        self._stats["calls"] += 1
         if not self.enabled or x_in.device.type != "cuda" or torch.cuda.is_current_stream_capturing():
+            self._stats["eager"] += 1
             self.last_call_info = {
                 "mode": "eager",
                 "reason": "ineligible",
@@ -84,6 +121,8 @@ class CUDAGraphDiTRunner:
         if entry is None:
             entry = self._capture(x_in, c, input_pos, mask)
             if entry is None:
+                self._stats["capture_failures"] += 1
+                self._stats["eager"] += 1
                 self.last_call_info = {
                     "mode": "eager",
                     "reason": "capture_failed",
@@ -91,10 +130,12 @@ class CUDAGraphDiTRunner:
                     "cache_size": len(self._cache),
                 }
                 return self.transformer(x_in, c, input_pos, mask)
+            self._stats["captures"] += 1
             self._cache[key] = entry
             while len(self._cache) > self.max_graphs:
                 _, evicted = self._cache.popitem(last=False)
                 del evicted
+                self._stats["evictions"] += 1
             # Kernels are only recorded (not executed) during capture, so
             # replay once to produce the first real output.
             entry.graph.replay()
@@ -104,22 +145,20 @@ class CUDAGraphDiTRunner:
                 "shape": tuple(x_in.shape),
                 "cache_size": len(self._cache),
             }
-            return entry.static_out.clone()
+            return entry.static_out
 
         self._cache.move_to_end(key)
-        entry.static_x.copy_(x_in)
-        entry.static_c.copy_(c)
-        entry.static_pos.copy_(input_pos)
-        if entry.static_mask is not None and mask is not None:
-            entry.static_mask.copy_(mask)
-        entry.graph.replay()
+        self._stats["hits"] += 1
+        output = self._replay(entry, x_in=x_in, c=c)
         self.last_call_info = {
             "mode": "graph",
             "reason": "hit",
             "shape": tuple(x_in.shape),
             "cache_size": len(self._cache),
         }
-        return entry.static_out.clone()
+        if self._stats["calls"] % 1000 == 0:
+            logger.info("S2Mel DiT CUDA graph stats: %s", self.stats_snapshot())
+        return output
 
     def _capture(
         self,
diff --git a/vllm_omni/model_executor/models/indextts2/indextts2_s2mel_decoder.py b/vllm_omni/model_executor/models/indextts2/indextts2_s2mel_decoder.py
index a374f1b45..a6fb66329 100644
--- a/vllm_omni/model_executor/models/indextts2/indextts2_s2mel_decoder.py
+++ b/vllm_omni/model_executor/models/indextts2/indextts2_s2mel_decoder.py
@@ -16,17 +16,28 @@ from typing import Any
 
 import torch
 import torch.nn as nn
+import torch.nn.functional as F
 from vllm.config import VllmConfig
 from vllm.logger import init_logger
 from vllm.model_executor.model_loader.weight_utils import default_weight_loader
 from vllm.sequence import IntermediateTensors
+from vllm.utils.torch_utils import set_default_torch_dtype
 
 from vllm_omni.diffusion.model_loader.hub_prefetch import _repo_prefetch_lock
 from vllm_omni.model_executor.models.output_templates import OmniOutput
 
-from .configuration_indextts2 import IndexTTS2Config
-from .preprocess_utils import load_semantic_codec, resolve_model_file
+from .configuration_indextts2 import (
+    INDEXTTS25_MAX_DURATION_FACTOR,
+    INDEXTTS25_MIN_DURATION_FACTOR,
+    IndexTTS2Config,
+)
+from .preprocess_utils import (
+    load_semantic_codec,
+    resolve_model_directory,
+    resolve_model_file,
+)
 from .s2mel.modules.commons import AttrDict, MyModel
+from .s2mel.modules.flow_matching import build_cfm_unpad_data
 
 logger = init_logger(__name__)
 
@@ -38,6 +49,40 @@ logger = init_logger(__name__)
 _bigvgan_models: dict[tuple[str, str], nn.Module] = {}
 
 
+def _raise_if_cuda_runtime_error(error: BaseException) -> None:
+    if isinstance(error, torch.cuda.OutOfMemoryError):
+        raise error
+    if not isinstance(error, RuntimeError):
+        return
+    message = str(error).lower()
+    cuda_markers = (
+        "cuda error",
+        "device-side assert",
+        "illegal memory access",
+        "out of memory",
+        "cublas",
+        "cudnn",
+        "cufft",
+    )
+    if any(marker in message for marker in cuda_markers):
+        raise error
+
+
+def _resolve_bigvgan_source(model_path: str, vocoder_name: str) -> str:
+    if os.path.isdir(vocoder_name):
+        return vocoder_name
+    local_dir = resolve_model_directory(
+        model_path,
+        "bigvgan",
+        os.path.join("hf_cache", "bigvgan"),
+    )
+    if local_dir is not None:
+        return local_dir
+    if os.path.isdir(model_path):
+        raise FileNotFoundError(f"IndexTTS BigVGAN assets are missing from local bundle {model_path!r}")
+    return vocoder_name
+
+
 def _patch_bigvgan_compat(cls):
     """Monkey-patch BigVGAN._from_pretrained for huggingface_hub>=1.0 compat."""
     if getattr(cls._from_pretrained, "_hf1_patched", False):
@@ -78,6 +123,25 @@ def _strip_weight_norm(root: nn.Module) -> list[str]:
     return folded
 
 
+def _precast_cfm_estimator_bf16(
+    estimator: nn.Module,
+    *,
+    enabled: bool,
+) -> int:
+    """Pre-cast CFM GEMM/conv parameters while keeping other layers in fp32."""
+    if not enabled:
+        return 0
+
+    parameter_count = 0
+    for module in estimator.modules():
+        if not isinstance(module, (nn.Linear, nn.Conv1d)):
+            continue
+        for parameter in module.parameters(recurse=False):
+            parameter.data = parameter.data.to(dtype=torch.bfloat16)
+            parameter_count += parameter.numel()
+    return parameter_count
+
+
 def _load_bigvgan(vocoder_name: str, device: torch.device, dtype: torch.dtype = torch.float32):
     cache_key = (vocoder_name, str(device), str(dtype))
     if cache_key in _bigvgan_models:
@@ -87,23 +151,25 @@ def _load_bigvgan(vocoder_name: str, device: torch.device, dtype: torch.dtype =
     if lock is not None:
         lock.__enter__()
     try:
-        try:
-            from .s2mel.modules import bigvgan as bigvgan_mod
+        with set_default_torch_dtype(torch.float32):
+            try:
+                from .s2mel.modules import bigvgan as bigvgan_mod
 
-            _patch_bigvgan_compat(bigvgan_mod.BigVGAN)
-            bigvgan_model = bigvgan_mod.BigVGAN.from_pretrained(vocoder_name)
-        except (ImportError, ModuleNotFoundError):
-            import bigvgan
+                _patch_bigvgan_compat(bigvgan_mod.BigVGAN)
+                bigvgan_model = bigvgan_mod.BigVGAN.from_pretrained(vocoder_name)
+            except (ImportError, ModuleNotFoundError):
+                import bigvgan
 
-            _patch_bigvgan_compat(bigvgan.BigVGAN)
-            bigvgan_model = bigvgan.BigVGAN.from_pretrained(vocoder_name)
+                _patch_bigvgan_compat(bigvgan.BigVGAN)
+                bigvgan_model = bigvgan.BigVGAN.from_pretrained(vocoder_name)
+            # Fold weight norm while its normalization is still computed in
+            # fp32. The vLLM model loader may otherwise leave the process-wide
+            # default dtype set to the stage's low-precision model dtype here.
+            bigvgan_model.remove_weight_norm()
     finally:
         if lock is not None:
             lock.__exit__(None, None, None)
-    # One-time weight cast (vs per-call autocast, which re-casts every conv's
-    # fp32 weights on each forward and is slower than fp32 on BigVGAN).
     bigvgan_model = bigvgan_model.to(device=device, dtype=dtype).eval()
-    bigvgan_model.remove_weight_norm()
     for p in bigvgan_model.parameters():
         p.requires_grad_(False)
     _bigvgan_models[cache_key] = bigvgan_model
@@ -131,6 +197,9 @@ class IndexTTS2S2MelDecoder(nn.Module):
         self.vllm_config = vllm_config
         self.model_path = vllm_config.model_config.model
         self.config: IndexTTS2Config = vllm_config.model_config.hf_config  # type: ignore[assignment]
+        self._resolved_vocoder_source: str | None = None
+        self.use_gpt_latent = bool(getattr(self.config, "use_gpt_latent", True))
+        self.semantic_codec_type = str(getattr(self.config, "semantic_codec_type", "repcodec"))
 
         # --- Flags for vLLM-Omni framework ---
         self.have_multimodal_outputs = True
@@ -147,12 +216,19 @@ class IndexTTS2S2MelDecoder(nn.Module):
             if key in s2mel_args and isinstance(s2mel_args[key], dict):
                 s2mel_args[key] = AttrDict(s2mel_args[key])
 
-        self.s2mel = MyModel(s2mel_args, use_emovec=False, use_gpt_latent=True)
+        self.s2mel = MyModel(
+            s2mel_args,
+            use_emovec=False,
+            use_gpt_latent=self.use_gpt_latent,
+        )
 
         # Diffusion config — configurable via deploy YAML hf_overrides
         self.diffusion_steps: int = getattr(self.config, "diffusion_steps", 25)
         self.inference_cfg_rate: float = getattr(self.config, "inference_cfg_rate", 0.7)
         self.mel_code_to_frame_ratio: float = 1.72
+        self.s2mel_cfm_batch_size: int = int(getattr(self.config, "s2mel_cfm_batch_size", 1))
+        if self.s2mel_cfm_batch_size < 1:
+            raise ValueError("s2mel_cfm_batch_size must be at least 1")
 
         # Run the DiT estimator under bf16 autocast (flash attention + faster
         # GEMMs); the CFM Euler solver stays float32. Disable via deploy YAML
@@ -164,22 +240,47 @@ class IndexTTS2S2MelDecoder(nn.Module):
         # Capture BigVGAN into bucketed CUDA graphs (collapses the Snake/conv
         # small-op launch storm). Enable via `s2mel_vocoder_cuda_graph: true`.
         self.s2mel_vocoder_cuda_graph: bool = getattr(self.config, "s2mel_vocoder_cuda_graph", False)
+        self.s2mel_vocoder_torch_compile: bool = getattr(
+            self.config,
+            "s2mel_vocoder_torch_compile",
+            False,
+        )
         self._vocoder_graph: Any = None
+        self._compiled_vocoder: Any = None
         # Capture the DiT transformer core into per-shape CUDA graphs.
         # Enable via `s2mel_dit_cuda_graph: true`.
         self.s2mel_dit_cuda_graph: bool = getattr(self.config, "s2mel_dit_cuda_graph", False)
+        self.s2mel_dit_torch_compile: bool = getattr(
+            self.config,
+            "s2mel_dit_torch_compile",
+            False,
+        )
+        self.s2mel_dit_torch_compile_mode: str = str(
+            getattr(
+                self.config,
+                "s2mel_dit_torch_compile_mode",
+                "default",
+            )
+        )
+        self._dit_runtime_configured = False
         self.s2mel_dit_cuda_graph_max_graphs: int = int(getattr(self.config, "s2mel_dit_cuda_graph_max_graphs", 8))
         self.s2mel_vocoder_capture_sizes: list[int] | None = getattr(self.config, "s2mel_vocoder_capture_sizes", None)
         self.s2mel_vocoder_compile_shapes: list[int] | None = getattr(self.config, "s2mel_vocoder_compile_shapes", None)
         logger.info(
             "[S2Mel] dit_bf16=%s, vocoder_bf16=%s, "
-            "vocoder_cuda_graph=%s, dit_cuda_graph=%s, dit_graph_lru=%d, vocoder_buckets=%s, "
+            "vocoder_cuda_graph=%s, vocoder_torch_compile=%s, "
+            "dit_cuda_graph=%s, dit_torch_compile=%s, dit_compile_mode=%s, "
+            "dit_graph_lru=%d, cfm_batch_size=%d, vocoder_buckets=%s, "
             "vocoder_compile_shapes=%s",
             self.s2mel_dit_bf16,
             self.s2mel_vocoder_bf16,
             self.s2mel_vocoder_cuda_graph,
+            self.s2mel_vocoder_torch_compile,
             self.s2mel_dit_cuda_graph,
+            self.s2mel_dit_torch_compile,
+            self.s2mel_dit_torch_compile_mode,
             self.s2mel_dit_cuda_graph_max_graphs,
+            self.s2mel_cfm_batch_size,
             self.s2mel_vocoder_capture_sizes,
             self.s2mel_vocoder_compile_shapes,
         )
@@ -214,9 +315,11 @@ class IndexTTS2S2MelDecoder(nn.Module):
         if model_intermediate_buffer:
             request_infos = [info for info in model_intermediate_buffer if isinstance(info, dict)]
         additional_information: dict[str, Any] = request_infos[0] if request_infos else {}
+        self._validate_payload_policy(request_infos)
+        self._validate_payload_contract(request_infos)
 
         device = input_ids.device
-        model_dtype = self.s2mel.models["gpt_layer"][0].weight.dtype
+        model_dtype = self._s2mel_model_dtype()
 
         logger.debug(
             "[S2Mel forward] model_intermediate_buffer len=%d, keys=%s",
@@ -231,7 +334,16 @@ class IndexTTS2S2MelDecoder(nn.Module):
         # one S2Mel batch. The runner can split list-valued multimodal outputs
         # back to per-request payloads, so never silently drop batched items.
         if len(request_infos) > 1:
-            mel_codes, latent, code_lens, code_lens_list, s_ref, ref_mel, style = self._build_batched_inputs(
+            (
+                mel_codes,
+                latent,
+                code_lens,
+                code_lens_list,
+                s_ref,
+                ref_mel,
+                style,
+                ref_lengths_list,
+            ) = self._build_batched_inputs(
                 request_infos,
                 device=device,
                 model_dtype=model_dtype,
@@ -239,19 +351,25 @@ class IndexTTS2S2MelDecoder(nn.Module):
             code_lens_raw = code_lens
         else:
             # Extract Stage 0 outputs and cast to model dtype
-            latent = self._get_tensor(additional_information, "latent", device, model_dtype)
+            latent = (
+                self._get_tensor(additional_information, "latent", device, model_dtype) if self.use_gpt_latent else None
+            )
             mel_codes = self._get_tensor(additional_information, "mel_codes", device)
             code_lens_raw = additional_information.get("code_lens")
             s_ref = self._get_tensor(additional_information, "S_ref", device)
             ref_mel = self._get_tensor(additional_information, "ref_mel", device, model_dtype)
             style = self._get_tensor(additional_information, "style", device, model_dtype)
+            ref_lengths_list = self._ref_mel_lengths([ref_mel])
 
-        if mel_codes is None or latent is None:
-            logger.warning("S2Mel decoder received empty mel_codes or latent")
-            return OmniOutput(
-                text_hidden_states=torch.zeros(1, device=device),
-                multimodal_outputs={"audio": torch.zeros(1, device=device), "sr": 22050},
-            )
+        if mel_codes is None or (self.use_gpt_latent and latent is None):
+            if not request_infos:
+                # vLLM profiles generation stages once with synthetic token
+                # inputs and no upstream payload during engine initialization.
+                return OmniOutput(
+                    text_hidden_states=torch.zeros(1, device=device),
+                    multimodal_outputs={"audio": torch.zeros(1, device=device), "sr": 22050},
+                )
+            raise ValueError("S2Mel decoder requires mel_codes" + (" and latent" if self.use_gpt_latent else ""))
 
         logger.debug(
             "[S2Mel] extracted tensors — mel_codes=%s latent=%s code_lens=%s s_ref=%s ref_mel=%s style=%s",
@@ -266,7 +384,7 @@ class IndexTTS2S2MelDecoder(nn.Module):
         # Ensure batch dimension
         if mel_codes.ndim == 1:
             mel_codes = mel_codes.unsqueeze(0)
-        if latent.ndim == 2:
+        if latent is not None and latent.ndim == 2:
             latent = latent.unsqueeze(0)
 
         # Compute code_lens
@@ -289,28 +407,34 @@ class IndexTTS2S2MelDecoder(nn.Module):
                 else:
                     code_lens_list.append(mel_codes.shape[1])
             code_lens = torch.tensor(code_lens_list, device=device, dtype=torch.long)
+        duration_factors = self._duration_factors(request_infos, len(code_lens_list))
 
         # Trim to actual length
         max_len = max(code_lens_list)
         mel_codes = mel_codes[:, :max_len]
-        latent = latent[:, :max_len, :]
+        if latent is not None:
+            latent = latent[:, :max_len, :]
         if logger.isEnabledFor(logging.DEBUG):
             logger.debug(
                 "[S2Mel] after trim — mel_codes=%s latent=%s code_lens=%s max_len=%d",
                 mel_codes.shape,
-                latent.shape,
+                latent.shape if latent is not None else None,
                 code_lens.tolist(),
                 max_len,
             )
 
         # --- S2Mel pipeline ---
-        # 1. Project GPT latent: 1280 → 1024
-        latent = latent.to(device=device, dtype=model_dtype)
-        latent = self.s2mel.forward_gpt(latent).to(dtype=model_dtype)  # [B, T, 1024]
-        logger.debug("[S2Mel] step1 forward_gpt → latent=%s dtype=%s", latent.shape, latent.dtype)
-
-        # 2. Embed mel codes via semantic codec vq2emb
-        semantic_codec = load_semantic_codec(self.model_path, self.config.semantic_codec, device)
+        semantic_codec = load_semantic_codec(
+            self.model_path,
+            self.config.semantic_codec,
+            device,
+            codec_type=self.semantic_codec_type,
+            checkpoint_name=getattr(
+                self.config,
+                "semantic_codec_checkpoint",
+                None,
+            ),
+        )
         codebook_size = self.config.semantic_codec.get("codebook_size", 8192)
         if logger.isEnabledFor(logging.DEBUG):
             logger.debug(
@@ -323,14 +447,30 @@ class IndexTTS2S2MelDecoder(nn.Module):
             (mel_codes < 0) | (mel_codes >= codebook_size)
         ):
             raise ValueError(f"IndexTTS2 generated mel code outside semantic codebook range [0, {codebook_size - 1}]")
-        with torch.no_grad():
-            S_infer = semantic_codec.quantizer.vq2emb(mel_codes.unsqueeze(1))  # [B, T, 1024]
-        S_infer = S_infer.transpose(1, 2).to(dtype=model_dtype)  # [B, T, 1024]
-        S_infer = S_infer + latent
-        logger.debug("[S2Mel] step2 vq2emb → S_infer=%s dtype=%s", S_infer.shape, S_infer.dtype)
+        S_infer = self._build_semantic_embedding(
+            codec=semantic_codec,
+            mel_codes=mel_codes,
+            latent=latent,
+            dtype=model_dtype,
+        )
+        logger.debug(
+            "[S2Mel] semantic decode → S_infer=%s dtype=%s codec=%s latent=%s",
+            S_infer.shape,
+            S_infer.dtype,
+            self.semantic_codec_type,
+            self.use_gpt_latent,
+        )
 
         # 3. Length regulate: codes → mel frames
-        target_lengths_list = [int(length * self.mel_code_to_frame_ratio) for length in code_lens_list]
+        semantic_time_scale = (
+            int(getattr(semantic_codec, "downsample_scale", 1) or 1) if self.semantic_codec_type == "enhanced" else 1
+        )
+        target_lengths_list = self._target_lengths(
+            code_lens_list,
+            semantic_time_scale=semantic_time_scale,
+            mel_code_to_frame_ratio=self.mel_code_to_frame_ratio,
+            duration_factors=duration_factors,
+        )
         target_lengths = torch.tensor(target_lengths_list, device=device, dtype=torch.long)
         if logger.isEnabledFor(logging.DEBUG):
             logger.debug("[S2Mel] step3 length_regulator target_lengths=%s", target_lengths_list)
@@ -364,11 +504,25 @@ class IndexTTS2S2MelDecoder(nn.Module):
                         codebook_size,
                     )
                 s_ref_codes = s_ref_codes.clamp(0, codebook_size - 1)
+                if self.semantic_codec_type != "repcodec":
+                    raise ValueError("IndexTTS 2.5 expects W2V-BERT reference embeddings, not semantic-code indices")
                 with torch.no_grad():
-                    s_ref_emb = semantic_codec.quantizer.vq2emb(s_ref_codes.unsqueeze(1))  # [B, 1024, T]
-                s_ref_emb = s_ref_emb.transpose(1, 2).to(dtype=model_dtype)  # [B, T, 1024]
+                    s_ref_emb = semantic_codec.quantizer.vq2emb(s_ref_codes.unsqueeze(1))
+                s_ref_emb = s_ref_emb.transpose(1, 2).to(dtype=model_dtype)
 
-            ref_target_lengths = self._infer_ref_lengths(ref_mel)
+            ref_batch_size = int(ref_mel.shape[0])
+            if len(ref_lengths_list) == 1 and ref_batch_size > 1:
+                ref_lengths_list = ref_lengths_list * ref_batch_size
+            if len(ref_lengths_list) != ref_batch_size:
+                raise ValueError(
+                    "IndexTTS reference-mel length/batch mismatch: "
+                    f"lengths={len(ref_lengths_list)} batch={ref_batch_size}"
+                )
+            ref_target_lengths = torch.tensor(
+                ref_lengths_list,
+                device=device,
+                dtype=torch.long,
+            )
             prompt_condition = self.s2mel.models["length_regulator"](
                 s_ref_emb, ylens=ref_target_lengths, n_quantizers=3, f0=None
             )[0]
@@ -380,12 +534,10 @@ class IndexTTS2S2MelDecoder(nn.Module):
                 cat_condition.shape,
             )
         else:
-            prompt_condition = None
-            cat_condition = cond
-            ref_mel = torch.zeros(cond.shape[0], 80, 0, device=device, dtype=model_dtype)
+            raise RuntimeError("IndexTTS Stage 1 payload validation allowed missing S_ref or ref_mel")
 
         if style is None:
-            style = torch.zeros(cat_condition.shape[0], 192, device=device, dtype=model_dtype)
+            raise RuntimeError("IndexTTS Stage 1 payload validation allowed missing style")
         if style.ndim == 1:
             style = style.unsqueeze(0)
 
@@ -401,6 +553,7 @@ class IndexTTS2S2MelDecoder(nn.Module):
         # 5. Flow matching inference (Euler ODE steps, CFG rate configurable)
         # CFM ODE solver runs in float32 — fp16 Euler steps diverge to noise.
         # The DiT estimator itself may run under bf16 autocast (see below).
+        self._configure_dit_runtime(device)
         cfm = self.s2mel.models["cfm"]
         cfm.estimator_autocast_dtype = torch.bfloat16 if self.s2mel_dit_bf16 else None
         cond = cond.float()
@@ -410,126 +563,51 @@ class IndexTTS2S2MelDecoder(nn.Module):
         ref_mel = ref_mel.float()
         style = style.float()
 
+        cfm_batch_size = int(cat_condition.shape[0])
         if prompt_condition is None:
-            ref_lengths = torch.zeros(cat_condition.shape[0], device=device, dtype=torch.long)
-        else:
-            ref_lengths = self._infer_ref_lengths(ref_mel)
-        ref_lengths_list = [int(length) for length in ref_lengths.tolist()]
-        if len(ref_lengths_list) == 1 and cat_condition.shape[0] > 1:
-            ref_lengths_list = ref_lengths_list * int(cat_condition.shape[0])
-            ref_lengths = ref_lengths.expand(int(cat_condition.shape[0]))
-        max_ref_len = int(ref_mel.size(-1))
-        ref_len = ref_lengths_list[0] if ref_lengths_list else max_ref_len
-        x_lens = target_lengths + ref_lengths
+            ref_lengths_list = [0] * cfm_batch_size
+        elif len(ref_lengths_list) != cfm_batch_size:
+            raise ValueError(
+                f"IndexTTS CFM reference-length/batch mismatch: lengths={len(ref_lengths_list)} batch={cfm_batch_size}"
+            )
 
         estimator = cfm.estimator
-        required_cache_batch = max(2, int(cat_condition.shape[0]) * (2 if self.inference_cfg_rate > 0 else 1))
+        max_cfm_group_size = min(cfm_batch_size, self.s2mel_cfm_batch_size)
+        required_cache_batch = max(2, max_cfm_group_size * (2 if self.inference_cfg_rate > 0 else 1))
         if (
             estimator.transformer.freqs_cis is None
             or getattr(estimator.transformer, "max_batch_size", -1) < required_cache_batch
         ):
             estimator.setup_caches(max_batch_size=required_cache_batch, max_seq_length=16384)
             logger.info("[S2Mel] DiT caches initialized (freqs_cis + causal_mask)")
-
-        cat_len = int(cat_condition.size(1))
-        x_lens_list = [target_len + ref_len_i for target_len, ref_len_i in zip(target_lengths_list, ref_lengths_list)]
-        same_ref_len = len(set(ref_lengths_list)) <= 1
-        same_target_len = len(set(target_lengths_list)) <= 1
-        dit_graph_full_mask = same_ref_len and same_target_len and all(length == cat_len for length in x_lens_list)
-        if dit_graph_full_mask:
-            self._enable_dit_cuda_graph(estimator)
-            with torch.no_grad():
-                mel = cfm.inference(
-                    cat_condition,
-                    x_lens,
-                    ref_mel,
-                    style,
-                    None,  # f0
-                    self.diffusion_steps,
-                    inference_cfg_rate=self.inference_cfg_rate,
-                )
-            # Strip reference portion
-            mel = mel[:, :, ref_len:]
-        else:
-            # Batched Stage-1 requests are padded to a shared length. The DiT
-            # CUDA graph fast path assumes a full mask, so rebuild each request
-            # with its exact reference/target lengths before enabling the graph.
-            mels_list: list[torch.Tensor] = []
-            for i in range(cat_condition.shape[0]):
-                self._enable_dit_cuda_graph(estimator)
-                ref_len_i = ref_lengths_list[i]
-                target_len_i = target_lengths_list[i]
-                if prompt_condition is not None:
-                    prompt_i = prompt_condition[i : i + 1, :ref_len_i]
-                    target_i = cond[i : i + 1, :target_len_i]
-                    cond_i = torch.cat([prompt_i, target_i], dim=1)
-                else:
-                    cond_i = cat_condition[i : i + 1, :target_len_i]
-                x_lens_i = torch.tensor([ref_len_i + target_len_i], device=device, dtype=torch.long)
-                ref_mel_i = ref_mel[i : i + 1, :, :ref_len_i] if ref_mel.ndim == 3 else ref_mel[:, :ref_len_i]
-                style_i = style[i : i + 1] if style.ndim == 2 else style
-                with torch.no_grad():
-                    mel_i = cfm.inference(
-                        cond_i,
-                        x_lens_i,
-                        ref_mel_i,
-                        style_i,
-                        None,
-                        self.diffusion_steps,
-                        inference_cfg_rate=self.inference_cfg_rate,
-                    )
-                mels_list.append(mel_i[0, :, ref_len_i:])
-            mel = mels_list
-        dit_graph_info = getattr(getattr(estimator, "_cuda_graph_runner", None), "last_call_info", None)
-        mel_shape = [tuple(m.shape) for m in mel] if isinstance(mel, list) else tuple(mel.shape)
-        logger.debug("[S2Mel] step5 CFM done → mel=%s (stripped ref %d frames)", mel_shape, ref_len)
+        cfm_seeds = self._cfm_request_seeds(
+            request_infos,
+            batch_size=int(cat_condition.shape[0]),
+        )
+        mel = self._run_cfm_groups(
+            cfm=cfm,
+            cond=cond,
+            prompt_condition=prompt_condition,
+            ref_mel=ref_mel,
+            style=style,
+            target_lengths=target_lengths_list,
+            ref_lengths=ref_lengths_list,
+            seeds=cfm_seeds,
+            max_group_size=self.s2mel_cfm_batch_size,
+        )
+        logger.debug("[S2Mel] step5 CFM done → mel=%s", [tuple(item.shape) for item in mel])
 
         # 6. BigVGAN vocoding
-        vocoder_cfg = self.config.vocoder
-        vocoder_name = vocoder_cfg.get("name", "nvidia/bigvgan_v2_22khz_80band_256x")
+        vocoder_name = self._get_resolved_vocoder_source()
         voc_dtype = torch.bfloat16 if (self.s2mel_vocoder_bf16 and device.type == "cuda") else torch.float32
         bigvgan = _load_bigvgan(vocoder_name, device, voc_dtype)
-        vocode = self._get_vocoder_graph(bigvgan, device, voc_dtype)
-        upsample_factor = int(math.prod(bigvgan.h.upsample_rates))
+        vocode = self._get_vocoder_runner(bigvgan, device, voc_dtype)
         with torch.no_grad():
-            wavs: list[torch.Tensor] = []
-            vocoder_infos: list[dict[str, Any]] = []
-            if isinstance(mel, list):
-                # Per-request CFM output: variable-length mels. Batch them
-                # for BigVGAN by padding to the max length.
-                batch_size = len(mel)
-                if batch_size == 1:
-                    mel_i = mel[0:1].to(voc_dtype) if mel[0].ndim == 3 else mel[0].unsqueeze(0).to(voc_dtype)
-                    wav_i = vocode(mel_i).float().squeeze(0).squeeze(0)
-                    wavs.append(torch.clamp(wav_i, -1.0, 1.0))
-                    last_call_info = getattr(vocode, "last_call_info", None)
-                    if isinstance(last_call_info, dict):
-                        vocoder_infos.append(dict(last_call_info))
-                else:
-                    for i in range(batch_size):
-                        mel_i = mel[i].unsqueeze(0).to(voc_dtype) if mel[i].ndim == 2 else mel[i : i + 1].to(voc_dtype)
-                        wav_i = vocode(mel_i).float().squeeze(0).squeeze(0)
-                        wavs.append(torch.clamp(wav_i, -1.0, 1.0))
-                        last_call_info = getattr(vocode, "last_call_info", None)
-                        if isinstance(last_call_info, dict):
-                            vocoder_infos.append(dict(last_call_info))
-            else:
-                batch_size = mel.shape[0]
-                if batch_size == 1:
-                    mel_i = mel[:, :, : target_lengths_list[0]].to(voc_dtype)
-                    wav_i = vocode(mel_i).float().squeeze(0).squeeze(0)
-                    wavs.append(torch.clamp(wav_i, -1.0, 1.0))
-                    last_call_info = getattr(vocode, "last_call_info", None)
-                    if isinstance(last_call_info, dict):
-                        vocoder_infos.append(dict(last_call_info))
-                else:
-                    for i in range(batch_size):
-                        mel_i = mel[i : i + 1, :, : target_lengths_list[i]].to(voc_dtype)
-                        wav_i = vocode(mel_i).float().squeeze(0).squeeze(0)
-                        wavs.append(torch.clamp(wav_i, -1.0, 1.0))
-                        last_call_info = getattr(vocode, "last_call_info", None)
-                        if isinstance(last_call_info, dict):
-                            vocoder_infos.append(dict(last_call_info))
+            wavs = self._vocode_mels(
+                mels=mel,
+                vocode=vocode,
+                voc_dtype=voc_dtype,
+            )
         wav: torch.Tensor | list[torch.Tensor] = wavs[0] if len(wavs) == 1 else wavs
 
         # Keep the public vLLM-Omni audio contract as normalized float. This is
@@ -563,6 +641,307 @@ class IndexTTS2S2MelDecoder(nn.Module):
     # Helpers
     # ------------------------------------------------------------------
 
+    def _s2mel_model_dtype(self) -> torch.dtype:
+        if self.use_gpt_latent:
+            return self.s2mel.models["gpt_layer"][0].weight.dtype
+        return next(self.s2mel.models["length_regulator"].parameters()).dtype
+
+    def _validate_payload_policy(self, infos: list[dict[str, Any]]) -> None:
+        for index, info in enumerate(infos):
+            if "use_gpt_latent" not in info:
+                raise ValueError(f"IndexTTS Stage 1 input {index} is missing use_gpt_latent")
+            payload_value = info["use_gpt_latent"]
+            if bool(payload_value) != self.use_gpt_latent:
+                raise ValueError(
+                    "IndexTTS Stage 1 use_gpt_latent mismatch for input "
+                    f"{index}: payload={bool(payload_value)} "
+                    f"stage_config={self.use_gpt_latent}"
+                )
+
+    @staticmethod
+    def _validate_payload_contract(infos: list[dict[str, Any]]) -> None:
+        for index, info in enumerate(infos):
+            for key in ("mel_codes", "S_ref", "ref_mel", "style"):
+                value = info.get(key)
+                if not isinstance(value, torch.Tensor) or value.numel() == 0:
+                    raise ValueError(f"IndexTTS Stage 1 input {index} is missing non-empty {key}")
+
+    @staticmethod
+    def _duration_factors(infos: list[dict[str, Any]], batch_size: int) -> list[float]:
+        factors = [float(info.get("duration_factor", 1.0)) for info in infos] if infos else [1.0] * batch_size
+        if len(factors) != batch_size:
+            raise ValueError(f"IndexTTS duration-factor batch mismatch: factors={len(factors)} batch={batch_size}")
+        if any(
+            not math.isfinite(factor) or not INDEXTTS25_MIN_DURATION_FACTOR <= factor <= INDEXTTS25_MAX_DURATION_FACTOR
+            for factor in factors
+        ):
+            raise ValueError("IndexTTS duration_factor values must be finite and between 0.5 and 2.0")
+        return factors
+
+    @staticmethod
+    def _target_lengths(
+        code_lens: list[int],
+        *,
+        semantic_time_scale: int,
+        mel_code_to_frame_ratio: float,
+        duration_factors: list[float],
+    ) -> list[int]:
+        if len(code_lens) != len(duration_factors):
+            raise ValueError(
+                f"IndexTTS target-length batch mismatch: codes={len(code_lens)} factors={len(duration_factors)}"
+            )
+        return [
+            int(length * semantic_time_scale * mel_code_to_frame_ratio * factor)
+            for length, factor in zip(code_lens, duration_factors)
+        ]
+
+    def _run_cfm_groups(
+        self,
+        *,
+        cfm: Any,
+        cond: torch.Tensor,
+        prompt_condition: torch.Tensor | None,
+        ref_mel: torch.Tensor,
+        style: torch.Tensor,
+        target_lengths: list[int],
+        ref_lengths: list[int],
+        seeds: list[int | None],
+        max_group_size: int,
+    ) -> list[torch.Tensor]:
+        """Run tightly packed CFM groups and restore original request order."""
+        batch_size = int(cond.shape[0])
+        if max_group_size < 1:
+            raise ValueError("IndexTTS CFM max_group_size must be at least 1")
+        if not (len(target_lengths) == len(ref_lengths) == len(seeds) == batch_size):
+            raise ValueError(
+                "IndexTTS CFM input batch mismatch: "
+                f"batch={batch_size} target={len(target_lengths)} "
+                f"ref={len(ref_lengths)} seeds={len(seeds)}"
+            )
+        if batch_size == 0:
+            return []
+
+        total_lengths = [ref_len + target_len for ref_len, target_len in zip(ref_lengths, target_lengths)]
+        # Python's sort is stable, so equal total lengths preserve arrival order.
+        sorted_indices = sorted(
+            range(batch_size),
+            key=total_lengths.__getitem__,
+        )
+        outputs: list[torch.Tensor | None] = [None] * batch_size
+        estimator = cfm.estimator
+        runtime_estimator = getattr(estimator, "_orig_mod", estimator)
+        wavenet = getattr(runtime_estimator, "wavenet", None)
+        min_ragged_length = int(getattr(wavenet, "ragged_min_length", 1))
+        groups = self._cfm_group_indices(
+            sorted_indices=sorted_indices,
+            total_lengths=total_lengths,
+            max_group_size=max_group_size,
+            min_ragged_length=min_ragged_length,
+        )
+
+        for group_indices in groups:
+            group_ref_lengths = [ref_lengths[index] for index in group_indices]
+            group_target_lengths = [target_lengths[index] for index in group_indices]
+            group_x_lengths = [
+                ref_len + target_len for ref_len, target_len in zip(group_ref_lengths, group_target_lengths)
+            ]
+            group_length = max(group_x_lengths)
+            group_prompt_length = max(group_ref_lengths)
+
+            packed_condition = cond.new_zeros(
+                len(group_indices),
+                group_length,
+                cond.shape[-1],
+            )
+            packed_prompt = ref_mel.new_zeros(
+                len(group_indices),
+                ref_mel.shape[1],
+                group_prompt_length,
+            )
+            for row, (index, ref_len, target_len) in enumerate(
+                zip(group_indices, group_ref_lengths, group_target_lengths)
+            ):
+                if ref_len:
+                    if prompt_condition is None:
+                        raise ValueError("IndexTTS CFM reference length requires prompt conditioning")
+                    packed_condition[row, :ref_len].copy_(prompt_condition[index, :ref_len])
+                    packed_prompt[row, :, :ref_len].copy_(ref_mel[index, :, :ref_len])
+                packed_condition[row, ref_len : ref_len + target_len].copy_(cond[index, :target_len])
+
+            group_index_tensor = torch.tensor(
+                group_indices,
+                device=style.device,
+                dtype=torch.long,
+            )
+            packed_style = style.index_select(0, group_index_tensor)
+            x_lens = torch.tensor(
+                group_x_lengths,
+                device=cond.device,
+                dtype=torch.long,
+            )
+            prompt_lens = torch.tensor(
+                group_ref_lengths,
+                device=cond.device,
+                dtype=torch.long,
+            )
+            full_mask = all(length == group_length for length in group_x_lengths)
+            self._set_dit_full_mask_fast_path(estimator, enabled=full_mask)
+            if full_mask:
+                self._enable_dit_cuda_graph(estimator)
+            unpad_data = None
+            if not full_mask:
+                token_offset = int(bool(getattr(runtime_estimator, "style_as_token", False))) + int(
+                    bool(getattr(runtime_estimator, "time_as_token", False))
+                )
+                unpad_data = build_cfm_unpad_data(
+                    group_x_lengths,
+                    padded_length=group_length,
+                    token_offset=token_offset,
+                    repeat_for_cfg=self.inference_cfg_rate > 0,
+                    device=cond.device,
+                )
+
+            initial_noise = self._sample_cfm_noise(
+                seeds=[seeds[index] for index in group_indices],
+                channels=cfm.in_channels,
+                length=group_length,
+                lengths=group_x_lengths,
+                device=cond.device,
+                dtype=cond.dtype,
+            )
+            with torch.no_grad():
+                group_mel = cfm.inference(
+                    packed_condition,
+                    x_lens,
+                    packed_prompt,
+                    packed_style,
+                    None,
+                    self.diffusion_steps,
+                    inference_cfg_rate=self.inference_cfg_rate,
+                    initial_noise=initial_noise,
+                    prompt_lens=prompt_lens,
+                    unpad_data=unpad_data,
+                )
+
+            for row, (index, ref_len, target_len) in enumerate(
+                zip(group_indices, group_ref_lengths, group_target_lengths)
+            ):
+                outputs[index] = group_mel[row, :, ref_len : ref_len + target_len]
+
+        if any(output is None for output in outputs):
+            raise RuntimeError("IndexTTS CFM failed to produce every request output")
+        return [output for output in outputs if output is not None]
+
+    @staticmethod
+    def _cfm_group_indices(
+        *,
+        sorted_indices: list[int],
+        total_lengths: list[int],
+        max_group_size: int,
+        min_ragged_length: int,
+    ) -> list[list[int]]:
+        """Build packed groups while preserving exact short-input semantics."""
+        groups: list[list[int]] = []
+        start = 0
+        while start < len(sorted_indices):
+            index = sorted_indices[start]
+            group_size = 1 if total_lengths[index] < min_ragged_length else max_group_size
+            group = sorted_indices[start : start + group_size]
+            groups.append(group)
+            start += len(group)
+        return groups
+
+    @staticmethod
+    def _cfm_request_seeds(
+        infos: list[dict[str, Any]],
+        *,
+        batch_size: int,
+    ) -> list[int | None]:
+        seeds: list[int | None] = []
+        for info in infos:
+            seed = info.get("seed")
+            if isinstance(seed, torch.Tensor):
+                seed = seed.reshape(-1)[0].item() if seed.numel() else None
+            elif isinstance(seed, (list, tuple)):
+                seed = seed[0] if seed else None
+            seeds.append(int(seed) if seed is not None else None)
+
+        if not seeds:
+            return [None] * batch_size
+        if len(seeds) != batch_size:
+            raise ValueError(f"IndexTTS CFM seed/request batch mismatch: seeds={len(seeds)} batch={batch_size}")
+        return seeds
+
+    @staticmethod
+    def _sample_cfm_noise(
+        *,
+        seeds: list[int | None],
+        channels: int,
+        length: int,
+        lengths: list[int] | None = None,
+        device: torch.device,
+        dtype: torch.dtype,
+    ) -> torch.Tensor | None:
+        if not seeds or all(seed is None for seed in seeds):
+            return None
+        if lengths is not None and len(lengths) != len(seeds):
+            raise ValueError(f"IndexTTS CFM noise length/seed mismatch: lengths={len(lengths)} seeds={len(seeds)}")
+
+        rows: list[torch.Tensor] = []
+        for index, seed in enumerate(seeds):
+            row_length = lengths[index] if lengths is not None else length
+            if row_length < 0 or row_length > length:
+                raise ValueError(f"IndexTTS CFM noise length out of range: row={row_length} padded={length}")
+            generator = None
+            if seed is not None:
+                generator = torch.Generator(device=device)
+                generator.manual_seed(seed)
+            row = torch.randn(
+                (1, channels, row_length),
+                device=device,
+                dtype=dtype,
+                generator=generator,
+            )
+            rows.append(F.pad(row, (0, length - row_length)))
+        return torch.cat(rows, dim=0)
+
+    def _build_semantic_embedding(
+        self,
+        *,
+        codec: Any,
+        mel_codes: torch.Tensor,
+        latent: torch.Tensor | None,
+        dtype: torch.dtype,
+    ) -> torch.Tensor:
+        if self.semantic_codec_type == "enhanced":
+            semantic = codec.decode(mel_codes)
+        else:
+            semantic = codec.quantizer.vq2emb(mel_codes.unsqueeze(1))
+            semantic = semantic.transpose(1, 2)
+        semantic = semantic.to(device=mel_codes.device, dtype=dtype)
+
+        if not self.use_gpt_latent:
+            return semantic
+        if latent is None:
+            raise ValueError("IndexTTS GPT latent mode requires a latent tensor")
+
+        projected = self.s2mel.forward_gpt(latent.to(device=mel_codes.device, dtype=dtype)).to(dtype=dtype)
+        if projected.shape[1] != semantic.shape[1]:
+            # EnhancedCodec restores the encoder's temporal downsampling with
+            # nearest-neighbor upsampling. Mirror that time mapping for the
+            # optional GPT residual before addition.
+            projected = F.interpolate(
+                projected.transpose(1, 2),
+                size=semantic.shape[1],
+                mode="nearest",
+            ).transpose(1, 2)
+        if projected.shape != semantic.shape:
+            raise ValueError(
+                "IndexTTS semantic/GPT latent shape mismatch after alignment: "
+                f"semantic={tuple(semantic.shape)} latent={tuple(projected.shape)}"
+            )
+        return semantic + projected
+
     def _build_batched_inputs(
         self,
         infos: list[dict[str, Any]],
@@ -571,12 +950,13 @@ class IndexTTS2S2MelDecoder(nn.Module):
         model_dtype: torch.dtype,
     ) -> tuple[
         torch.Tensor,
-        torch.Tensor,
+        torch.Tensor | None,
         torch.Tensor,
         list[int],
         torch.Tensor | None,
         torch.Tensor | None,
         torch.Tensor | None,
+        list[int],
     ]:
         stop_token = self.config.gpt.get("stop_mel_token", 8193)
         mel_items: list[torch.Tensor] = []
@@ -588,15 +968,18 @@ class IndexTTS2S2MelDecoder(nn.Module):
 
         for idx, info in enumerate(infos):
             mel = self._get_tensor(info, "mel_codes", device)
-            latent = self._get_tensor(info, "latent", device, model_dtype)
-            if mel is None or latent is None:
-                raise ValueError(f"S2Mel batched input {idx} is missing mel_codes or latent")
+            latent = self._get_tensor(info, "latent", device, model_dtype) if self.use_gpt_latent else None
+            if mel is None or (self.use_gpt_latent and latent is None):
+                raise ValueError(
+                    f"S2Mel batched input {idx} is missing mel_codes" + (" or latent" if self.use_gpt_latent else "")
+                )
 
             mel = mel.to(device=device, dtype=torch.long).reshape(-1)
-            if latent.ndim == 3 and latent.shape[0] == 1:
-                latent = latent[0]
-            elif latent.ndim != 2:
-                latent = latent.reshape(-1, latent.shape[-1])
+            if latent is not None:
+                if latent.ndim == 3 and latent.shape[0] == 1:
+                    latent = latent[0]
+                elif latent.ndim != 2:
+                    latent = latent.reshape(-1, latent.shape[-1])
 
             raw_len = info.get("code_lens")
             if isinstance(raw_len, torch.Tensor) and raw_len.numel() > 0:
@@ -606,9 +989,16 @@ class IndexTTS2S2MelDecoder(nn.Module):
             else:
                 stop_mask = (mel == stop_token).nonzero(as_tuple=False)
                 code_len = int(stop_mask[0].item()) if stop_mask.numel() > 0 else int(mel.shape[0])
-            code_len = max(0, min(code_len, int(mel.shape[0]), int(latent.shape[0])))
+            code_len = max(0, min(code_len, int(mel.shape[0])))
+            if latent is not None:
+                if int(latent.shape[0]) != int(mel.shape[0]):
+                    raise ValueError(
+                        f"S2Mel batched input {idx} mel/latent length mismatch: "
+                        f"mel={mel.shape[0]} latent={latent.shape[0]}"
+                    )
             mel_items.append(mel[:code_len])
-            latent_items.append(latent[:code_len])
+            if latent is not None:
+                latent_items.append(latent[:code_len])
             code_lens.append(code_len)
 
             s_ref = self._get_tensor(info, "S_ref", device)
@@ -627,17 +1017,28 @@ class IndexTTS2S2MelDecoder(nn.Module):
             style_items.append(style)
 
         max_code_len = max(code_lens) if code_lens else 0
-        latent_dim = latent_items[0].shape[-1]
         # Padding reaches vq2emb before length masking, so it must be a valid
         # semantic-code index. Actual sequence lengths are still carried by
         # code_lens/target_lengths; stop_token (8193) is outside the codebook.
         mel_batch = torch.zeros((len(mel_items), max_code_len), dtype=torch.long, device=device)
-        latent_batch = torch.zeros(len(latent_items), max_code_len, latent_dim, device=device, dtype=model_dtype)
-        for i, (mel, latent) in enumerate(zip(mel_items, latent_items)):
+        latent_batch: torch.Tensor | None = None
+        if self.use_gpt_latent:
+            latent_dim = latent_items[0].shape[-1]
+            latent_batch = torch.zeros(
+                len(latent_items),
+                max_code_len,
+                latent_dim,
+                device=device,
+                dtype=model_dtype,
+            )
+        for i, mel in enumerate(mel_items):
             mel_batch[i, : mel.shape[0]] = mel
-            latent_batch[i, : latent.shape[0]] = latent.to(dtype=model_dtype)
+            if latent_batch is not None:
+                latent = latent_items[i]
+                latent_batch[i, : latent.shape[0]] = latent.to(dtype=model_dtype)
 
         s_ref_batch = self._stack_optional_sequence(s_ref_items, device=device, dtype=model_dtype)
+        ref_lengths = self._ref_mel_lengths(ref_mel_items)
         ref_mel_batch = self._stack_optional_ref_mel(ref_mel_items, device=device, dtype=model_dtype)
         style_batch = self._stack_optional_style(style_items, device=device, dtype=model_dtype)
         return (
@@ -648,6 +1049,7 @@ class IndexTTS2S2MelDecoder(nn.Module):
             s_ref_batch,
             ref_mel_batch,
             style_batch,
+            ref_lengths,
         )
 
     @staticmethod
@@ -702,12 +1104,11 @@ class IndexTTS2S2MelDecoder(nn.Module):
         )
 
     @staticmethod
-    def _infer_ref_lengths(ref_mel: torch.Tensor) -> torch.Tensor:
-        if ref_mel.ndim == 2:
-            return torch.tensor([ref_mel.size(-1)], device=ref_mel.device, dtype=torch.long)
-        nonzero = ref_mel.abs().sum(dim=1) > 0
-        lengths = nonzero.long().sum(dim=1)
-        return torch.clamp(lengths, min=1).to(device=ref_mel.device, dtype=torch.long)
+    def _ref_mel_lengths(items: list[torch.Tensor | None]) -> list[int]:
+        """Return unpadded reference lengths without inspecting CUDA values."""
+        if not items or any(item is None for item in items):
+            return []
+        return [int(item.shape[-1]) for item in items if item is not None]
 
     @staticmethod
     def _get_tensor(
@@ -794,8 +1195,9 @@ class IndexTTS2S2MelDecoder(nn.Module):
         required_prefixes = [
             "s2mel.models.cfm.",
             "s2mel.models.length_regulator.",
-            "s2mel.models.gpt_layer.",
         ]
+        if self.use_gpt_latent:
+            required_prefixes.append("s2mel.models.gpt_layer.")
         missing_prefixes = [
             prefix for prefix in required_prefixes if not any(name.startswith(prefix) for name in loaded_params)
         ]
@@ -817,29 +1219,126 @@ class IndexTTS2S2MelDecoder(nn.Module):
         # recursively re-casting the module on every request.
         cfm = self.s2mel.models["cfm"]
         cfm.float()
+        precast_parameter_count = _precast_cfm_estimator_bf16(
+            cfm.estimator,
+            enabled=self.s2mel_dit_bf16,
+        )
+        if self.s2mel_dit_bf16:
+            logger.info(
+                "Pre-cast %d CFM estimator Linear/Conv1d parameters to bfloat16",
+                precast_parameter_count,
+            )
         cfm.estimator_autocast_dtype = torch.bfloat16 if self.s2mel_dit_bf16 else None
 
         self._warmup_external_models()
         return loaded_params
 
+    def _configure_dit_runtime(self, device: torch.device) -> None:
+        if self._dit_runtime_configured:
+            return
+        if self.s2mel_dit_torch_compile and self.s2mel_dit_cuda_graph:
+            raise ValueError(
+                "s2mel_dit_torch_compile and s2mel_dit_cuda_graph are mutually exclusive",
+            )
+        if self.s2mel_dit_torch_compile:
+            if device.type == "cuda":
+                self.s2mel.enable_torch_compile(
+                    mode=self.s2mel_dit_torch_compile_mode,
+                )
+                logger.info(
+                    "S2Mel DiT torch.compile enabled with mode=%s",
+                    self.s2mel_dit_torch_compile_mode,
+                )
+            else:
+                logger.info(
+                    "S2Mel DiT torch.compile skipped on device type %s",
+                    device.type,
+                )
+        self._dit_runtime_configured = True
+
     def _warmup_external_models(self) -> None:
         """Preload vocoder + semantic codec to eliminate first-request latency."""
         device = next((p.device for p in self.s2mel.parameters()), torch.device("cpu"))
         try:
-            vocoder_name = self.config.vocoder.get("name", "nvidia/bigvgan_v2_22khz_80band_256x")
+            vocoder_name = self._get_resolved_vocoder_source()
             voc_dtype = torch.bfloat16 if (self.s2mel_vocoder_bf16 and device.type == "cuda") else torch.float32
             bigvgan = _load_bigvgan(vocoder_name, device, voc_dtype)
-            load_semantic_codec(self.model_path, self.config.semantic_codec, device)
-            # Warm up the CUDA graph + torch.compile wrapper at load time so the
-            # ~95s compile cost is paid during startup rather than on the first
-            # request. Mirrors the Qwen3-TTS pattern (enable_cudagraph in
-            # load_weights). _get_vocoder_graph constructs the wrapper and calls
-            # warmup() on first access.
-            if self.s2mel_vocoder_cuda_graph and device.type == "cuda":
-                self._get_vocoder_graph(bigvgan, device, voc_dtype)
+            load_semantic_codec(
+                self.model_path,
+                self.config.semantic_codec,
+                device,
+                codec_type=self.semantic_codec_type,
+                checkpoint_name=getattr(
+                    self.config,
+                    "semantic_codec_checkpoint",
+                    None,
+                ),
+            )
+            if (self.s2mel_vocoder_cuda_graph or self.s2mel_vocoder_torch_compile) and device.type == "cuda":
+                self._get_vocoder_runner(bigvgan, device, voc_dtype)
             logger.info("BigVGAN + semantic codec preloaded")
         except Exception as e:
-            logger.warning("Failed to preload Stage 1 models: %s", e)
+            _raise_if_cuda_runtime_error(e)
+            raise RuntimeError("Failed to preload required IndexTTS Stage 1 models") from e
+
+    def _get_resolved_vocoder_source(self) -> str:
+        if self._resolved_vocoder_source is None:
+            vocoder_name = self.config.vocoder.get(
+                "name",
+                "nvidia/bigvgan_v2_22khz_80band_256x",
+            )
+            self._resolved_vocoder_source = _resolve_bigvgan_source(
+                self.model_path,
+                vocoder_name,
+            )
+        return self._resolved_vocoder_source
+
+    def _vocode_mels(
+        self,
+        *,
+        mels: list[torch.Tensor],
+        vocode: Any,
+        voc_dtype: torch.dtype,
+    ) -> list[torch.Tensor]:
+        """Vocode each already-cropped request at its exact mel length."""
+        wavs: list[torch.Tensor] = []
+        for mel in mels:
+            if mel.ndim == 2:
+                mel_input = mel.unsqueeze(0)
+            elif mel.ndim == 3 and mel.shape[0] == 1:
+                mel_input = mel
+            else:
+                raise ValueError(f"IndexTTS BigVGAN expects one mel per request, got {tuple(mel.shape)}")
+            wav = vocode(mel_input.to(voc_dtype)).float().squeeze(0).squeeze(0)
+            wavs.append(torch.clamp(wav, -1.0, 1.0))
+        return wavs
+
+    def _get_vocoder_runner(
+        self,
+        bigvgan: nn.Module,
+        device: torch.device,
+        dtype: torch.dtype,
+    ):
+        """Return the selected exact-length BigVGAN execution path."""
+        if self.s2mel_vocoder_torch_compile and self.s2mel_vocoder_cuda_graph:
+            raise ValueError(
+                "s2mel_vocoder_torch_compile and s2mel_vocoder_cuda_graph are mutually exclusive",
+            )
+        if self.s2mel_vocoder_cuda_graph:
+            return self._get_vocoder_graph(bigvgan, device, dtype)
+        if not self.s2mel_vocoder_torch_compile or device.type != "cuda":
+            return bigvgan
+        if self._compiled_vocoder is None:
+            self._compiled_vocoder = torch.compile(
+                bigvgan.forward,
+                mode="default",
+                fullgraph=False,
+                dynamic=True,
+            )
+            logger.info(
+                "BigVGAN dynamic torch.compile enabled with exact-length inputs",
+            )
+        return self._compiled_vocoder
 
     def _get_vocoder_graph(self, bigvgan: nn.Module, device: torch.device, dtype: torch.dtype):
         """Return the CUDA-graph vocoder wrapper, or the eager model when disabled.
@@ -867,23 +1366,41 @@ class IndexTTS2S2MelDecoder(nn.Module):
                 self._vocoder_graph.enabled = False
         return self._vocoder_graph
 
+    @staticmethod
+    def _set_dit_full_mask_fast_path(
+        estimator: nn.Module,
+        *,
+        enabled: bool,
+    ) -> None:
+        """Select dense attention and physical WaveNet reflect boundaries."""
+        runtime_estimator = getattr(estimator, "_orig_mod", estimator)
+        for layer in runtime_estimator.transformer.layers:
+            layer.attention._assume_full_mask = enabled
+        if hasattr(runtime_estimator, "wavenet"):
+            runtime_estimator.wavenet._assume_full_mask = enabled
+
+        # A graph captured with the dense-attention branch must never replay
+        # for a padded input. Keep its cache resident, but route this call
+        # through eager execution until a later full-mask call re-enables it.
+        graph_runner = getattr(runtime_estimator, "_cuda_graph_runner", None)
+        if graph_runner is not None and not enabled:
+            graph_runner.enabled = False
+
     def _enable_dit_cuda_graph(self, estimator: nn.Module) -> None:
         """Attach a per-shape CUDA graph runner to the DiT transformer core.
 
-        Sets `_assume_full_mask` on the attention modules: this decoder
-        always passes x_lens == T, so the padding mask is all-True and
-        dense attention is identical — the flag removes the backend's
-        per-step ``torch.any(~mask)`` D2H sync, which is also a
-        stream-capture blocker.
+        Full-mask semantics are enabled independently by
+        ``_set_dit_full_mask_fast_path`` so eager execution also avoids
+        the per-layer ``torch.any(~mask)`` host synchronization.
         """
         if not self.s2mel_dit_cuda_graph:
             return
-        if getattr(estimator, "_cuda_graph_runner", None) is not None:
+        graph_runner = getattr(estimator, "_cuda_graph_runner", None)
+        if graph_runner is not None:
+            graph_runner.enabled = True
             return
         from vllm_omni.model_executor.models.indextts2.dit_cuda_graph import CUDAGraphDiTRunner
 
-        for layer in estimator.transformer.layers:
-            layer.attention._assume_full_mask = True
         estimator._cuda_graph_runner = CUDAGraphDiTRunner(
             estimator.transformer,
             max_graphs=self.s2mel_dit_cuda_graph_max_graphs,
diff --git a/vllm_omni/model_executor/models/indextts2/indextts2_talker.py b/vllm_omni/model_executor/models/indextts2/indextts2_talker.py
index 2b1244ccc..f9eae0c6f 100644
--- a/vllm_omni/model_executor/models/indextts2/indextts2_talker.py
+++ b/vllm_omni/model_executor/models/indextts2/indextts2_talker.py
@@ -12,6 +12,7 @@ import json
 import math
 import re
 from collections.abc import Iterable
+from dataclasses import dataclass
 from typing import Any
 
 import numpy as np
@@ -38,7 +39,11 @@ from vllm_omni.data_entry_keys import OmniPayload
 from vllm_omni.model_executor.models.output_templates import OmniOutput
 from vllm_omni.utils.speaker_cache import get_speaker_cache
 
-from .configuration_indextts2 import IndexTTS2Config
+from .configuration_indextts2 import (
+    INDEXTTS25_MAX_DURATION_FACTOR,
+    INDEXTTS25_MIN_DURATION_FACTOR,
+    IndexTTS2Config,
+)
 from .gpt.conformer_encoder import ConformerEncoder
 from .gpt.embeddings import LearnedPositionEmbeddings
 from .gpt.perceiver import PerceiverResampler
@@ -56,6 +61,57 @@ from .preprocess_utils import (
 logger = init_logger(__name__)
 
 
+@dataclass(frozen=True)
+class IndexTTSConditioningPolicy:
+    prefix_tokens: int
+    uses_conformer_perceiver: bool
+    uses_campplus_projection: bool
+    uses_language_embedding: bool
+
+
+def resolve_indextts_conditioning_policy(model_type: str) -> IndexTTSConditioningPolicy:
+    if model_type == "indextts2_5":
+        return IndexTTSConditioningPolicy(
+            prefix_tokens=3,
+            uses_conformer_perceiver=False,
+            uses_campplus_projection=True,
+            uses_language_embedding=True,
+        )
+    return IndexTTSConditioningPolicy(
+        prefix_tokens=34,
+        uses_conformer_perceiver=True,
+        uses_campplus_projection=False,
+        uses_language_embedding=False,
+    )
+
+
+def _normalize_indextts_checkpoint_key(name: str) -> str:
+    """Remove FSDP wrapper path components from native checkpoint keys."""
+    return name.replace("_fsdp_wrapped_module.", "")
+
+
+def _require_exact_indextts_prefill_span(
+    *,
+    actual_span_len: int,
+    scheduled_span_len: int,
+    model_type: str,
+    lang: str,
+    text_token_count: int,
+) -> None:
+    """Reject prompt-sizing drift before it can move/remove ``start_mel``."""
+    if actual_span_len == scheduled_span_len:
+        return
+    raise ValueError(
+        "IndexTTS prefill embedding span mismatch: "
+        f"scheduled_span_len={scheduled_span_len}, "
+        f"actual_span_len={actual_span_len}, "
+        f"model_type={model_type}, lang={lang}, "
+        f"text_token_count={text_token_count}. "
+        "IndexTTS requires exact placeholder sizing and does not support "
+        "chunked prefill; keep enable_chunked_prefill=false."
+    )
+
+
 def _find_most_similar_cosine(query: torch.Tensor, matrix: torch.Tensor) -> int:
     sims = F.cosine_similarity(query.float(), matrix.float(), dim=1)
     return int(torch.argmax(sims).item())
@@ -82,6 +138,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         self.model_path = vllm_config.model_config.model
         self.config: IndexTTS2Config = vllm_config.model_config.hf_config  # type: ignore[assignment]
         gpt_cfg = self.config.gpt
+        self.conditioning_policy = resolve_indextts_conditioning_policy(self.config.model_type)
+        self.use_gpt_latent = bool(getattr(self.config, "use_gpt_latent", True))
 
         self.model_dim = gpt_cfg["model_dim"]
         self.num_layers = gpt_cfg["layers"]
@@ -100,26 +158,37 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         self.has_postprocess = True
         self.requires_raw_input_tokens = True
         self.enable_update_additional_information = True
-        # S2Mel consumes the complete code sequence only at request end, but
-        # the connector accumulator needs to observe each appendable AR delta.
-        # Keep runner request-end gating disabled and emit per-step rows from
-        # make_omni_output; the full-payload builder reconstructs the sequence.
-        self.omni_payload_at_request_end = False
+        # Stage 1 consumes the hidden-state stream only in the legacy
+        # ``use_gpt_latent`` mode.  IndexTTS 2.5 transports mel codes plus
+        # reference conditioning, so asking the generic runner to include
+        # hidden states would add a synchronous [num_tokens, model_dim] D2H
+        # copy on every decode step without adding anything to the payload.
+        self.omni_pooler_payload_include_hidden = self.use_gpt_latent
+        # S2Mel consumes the complete sequence only at request end. In latent
+        # mode the runner retains aligned code/latent deltas on GPU; no-latent
+        # mode reuses the CPU output-token history and retains only conditioning
+        # metadata here.
+        self.omni_payload_at_request_end = self.config.model_type == "indextts2_5"
         self.omni_request_end_token_ids = ()
         self._speaker_cache = get_speaker_cache()
         self.gpu_resident_buffer_keys: set[tuple[str, str]] = {
             ("codes", "mel"),
-            ("hidden_states", "latent"),
             ("meta", "mel_start_offset"),
-            ("meta", "latent_acc"),
             ("meta", "mel_code_count"),
         }
+        if self.use_gpt_latent:
+            self.gpu_resident_buffer_keys.update(
+                {
+                    ("hidden_states", "latent"),
+                    ("meta", "latent_acc"),
+                }
+            )
 
         # --- GPT-2 transformer (vLLM-native with PagedAttention) ---
         # Build a GPT2Config-like object for GPT2Block
         from transformers import GPT2Config as HFGpt2Config
 
-        max_seq_len = self.max_mel_tokens + self.max_text_tokens + self.condition_num_latent + 4
+        max_seq_len = self.max_mel_tokens + self.max_text_tokens + self.conditioning_policy.prefix_tokens + 3
         gpt2_config = HFGpt2Config(
             vocab_size=self.number_mel_codes,
             n_positions=max_seq_len,
@@ -149,7 +218,13 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         self.mel_embedding = nn.Embedding(self.number_mel_codes, self.model_dim)
         self.text_pos_embedding = LearnedPositionEmbeddings(self.max_text_tokens + 2, self.model_dim)
         self.mel_pos_embedding = LearnedPositionEmbeddings(self.max_mel_tokens + 2 + 1, self.model_dim)
-        self.speed_emb = nn.Embedding(2, self.model_dim)
+        if self.conditioning_policy.uses_campplus_projection:
+            from .tokenizer_v2_5 import LANGUAGE_DICT
+
+            self.spk_emb_proj = nn.Linear(192, self.model_dim)
+            self.lang_embedding = nn.Embedding(len(LANGUAGE_DICT) + 1, self.model_dim)
+        else:
+            self.speed_emb = nn.Embedding(2, self.model_dim)
         self.emo_layer = nn.Linear(self.model_dim, self.model_dim)
         self.emovec_layer = nn.Linear(1024, self.model_dim)
 
@@ -158,6 +233,7 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             self.mel_head = ParallelLMHead(
                 self.number_mel_codes,
                 self.model_dim,
+                bias=True,
                 quant_config=quant_config,
                 prefix=maybe_prefix(prefix, "mel_head"),
             )
@@ -169,21 +245,22 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         cond_cfg = gpt_cfg.get("condition_module", {})
         emo_cond_cfg = gpt_cfg.get("emo_condition_module", {})
 
-        self.conditioning_encoder = ConformerEncoder(
-            input_size=1024,
-            output_size=cond_cfg.get("output_size", 512),
-            linear_units=cond_cfg.get("linear_units", 2048),
-            attention_heads=cond_cfg.get("attention_heads", 8),
-            num_blocks=cond_cfg.get("num_blocks", 6),
-            input_layer=cond_cfg.get("input_layer", "conv2d2"),
-        )
-        self.perceiver_encoder = PerceiverResampler(
-            self.model_dim,
-            dim_context=cond_cfg.get("output_size", 512),
-            ff_mult=cond_cfg.get("perceiver_mult", 2),
-            heads=cond_cfg.get("attention_heads", 8),
-            num_latents=self.condition_num_latent,
-        )
+        if self.conditioning_policy.uses_conformer_perceiver:
+            self.conditioning_encoder = ConformerEncoder(
+                input_size=1024,
+                output_size=cond_cfg.get("output_size", 512),
+                linear_units=cond_cfg.get("linear_units", 2048),
+                attention_heads=cond_cfg.get("attention_heads", 8),
+                num_blocks=cond_cfg.get("num_blocks", 6),
+                input_layer=cond_cfg.get("input_layer", "conv2d2"),
+            )
+            self.perceiver_encoder = PerceiverResampler(
+                self.model_dim,
+                dim_context=cond_cfg.get("output_size", 512),
+                ff_mult=cond_cfg.get("perceiver_mult", 2),
+                heads=cond_cfg.get("attention_heads", 8),
+                num_latents=self.condition_num_latent,
+            )
 
         self.emo_conditioning_encoder = ConformerEncoder(
             input_size=1024,
@@ -202,7 +279,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         )
 
         # Padding masks for perceiver cross-attention
-        self.cond_mask_pad = nn.ConstantPad1d((self.condition_num_latent, 0), True)
+        if self.conditioning_policy.uses_conformer_perceiver:
+            self.cond_mask_pad = nn.ConstantPad1d((self.condition_num_latent, 0), True)
         self.emo_cond_mask_pad = nn.ConstantPad1d((1, 0), True)
 
         # --- Lazy-loaded external models ---
@@ -214,7 +292,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         # Initialize embeddings per GPT-2 convention
         for emb in [self.text_embedding, self.mel_embedding]:
             emb.weight.data.normal_(mean=0.0, std=0.02)
-        self.speed_emb.weight.data.normal_(mean=0.0, std=0.0)
+        if hasattr(self, "speed_emb"):
+            self.speed_emb.weight.data.normal_(mean=0.0, std=0.0)
 
     # ------------------------------------------------------------------
     # vLLM required hooks
@@ -283,14 +362,23 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             hidden_states = hidden_states.text_hidden_states
         if hidden_states is None or self.mel_head is None:
             return None
-        return self.logits_processor(self.mel_head, hidden_states)
+        # `LogitsProcessor` never reads `lm_head.bias`: the unquantized apply()
+        # path is `F.linear(x, layer.weight, bias)` where `bias` comes from the
+        # `embedding_bias` argument.  IndexTTS's mel head is `Linear(..., bias=True)`
+        # upstream, so the bias has to be passed explicitly or logits silently
+        # drop it.
+        return self.logits_processor(
+            self.mel_head,
+            hidden_states,
+            embedding_bias=getattr(self.mel_head, "bias", None),
+        )
 
     # ------------------------------------------------------------------
     # Omni multimodal output plumbing
     # ------------------------------------------------------------------
 
     def make_omni_output(self, model_outputs: torch.Tensor | OmniOutput, **kwargs: Any) -> OmniOutput:
-        """Collect mel_codes and hidden_states from intermediate buffer."""
+        """Build the per-step Stage 1 payload from the intermediate buffer."""
         if isinstance(model_outputs, OmniOutput):
             return model_outputs
 
@@ -303,58 +391,71 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
 
         device = hidden.device
         latent_dim = hidden.shape[-1]
-        _zero_codes = torch.zeros(0, 1, dtype=torch.long, device=device)
-        _zero_latent = torch.zeros(0, latent_dim, dtype=hidden.dtype, device=device)
+        _zero_codes = torch.zeros(0, 1, dtype=torch.long, device=device) if self.use_gpt_latent else None
+        _zero_latent = torch.zeros(0, latent_dim, dtype=hidden.dtype, device=device) if self.use_gpt_latent else None
 
         # Per-request lists: to_payload_element dispatches lists via
         # element[idx], giving correct per-request mapping even during
         # mixed prefill+decode steps. Zero-length placeholders for prefill
         # requests are harmless — torch.cat ignores them in accumulation.
         #
-        # Export semantics are appendable deltas for the existing full-payload
-        # accumulator: codes.mel is a 2-D row [1, 1], hidden_states.latent is
-        # the aligned one-row [1, D] slice from meta.latent_acc.
+        # Latent-mode exports are appendable deltas for the existing
+        # full-payload accumulator: codes.mel is a 2-D row [1, 1], while
+        # hidden_states.latent is the aligned one-row [1, D] slice from
+        # meta.latent_acc. No-latent mode only uses meta_list.
         mel_codes_list: list[torch.Tensor] = []
         latent_list: list[torch.Tensor] = []
         meta_list: list[dict[str, Any]] = []
 
         for info in info_dicts:
             if not isinstance(info, dict):
-                mel_codes_list.append(_zero_codes)
-                latent_list.append(_zero_latent)
+                if self.use_gpt_latent:
+                    assert _zero_codes is not None
+                    mel_codes_list.append(_zero_codes)
+                    assert _zero_latent is not None
+                    latent_list.append(_zero_latent)
                 meta_list.append({})
                 continue
-            codes = info.get("codes", {})
-            mc = codes.get("mel")
             info_meta = info.get("meta", {})
             # mel_len now comes from the int counter in meta, not from
             # code_seq.shape[0] (codes.mel is a single-token delta).
             mel_len = int(info_meta.get("mel_code_count", 0))
-            if isinstance(mc, torch.Tensor) and mc.numel() > 0 and mel_len > 0:
-                code_seq = mc.reshape(-1)
-                mel_codes_list.append(code_seq[-1:].reshape(1, 1).contiguous())
-            else:
-                mel_codes_list.append(_zero_codes)
 
-            lat_acc = info_meta.get("latent_acc")
-            if isinstance(lat_acc, torch.Tensor) and lat_acc.numel() > 0 and mel_len > 0:
-                lat_seq = lat_acc.reshape(-1, lat_acc.shape[-1]) if lat_acc.ndim != 2 else lat_acc
-                idx = min(max(mel_len - 1, 0), int(lat_seq.shape[0]) - 1)
-                latent_list.append(lat_seq[idx : idx + 1].contiguous())
-            else:
-                hs = info.get("hidden_states", {})
-                lat = hs.get("latent")
-                if isinstance(lat, torch.Tensor) and lat.numel() > 0:
-                    lat_seq = lat.reshape(-1, lat.shape[-1]) if lat.ndim != 2 else lat
-                    latent_list.append(lat_seq[-1:].contiguous())
+            if self.use_gpt_latent:
+                codes = info.get("codes", {})
+                mc = codes.get("mel")
+                if isinstance(mc, torch.Tensor) and mc.numel() > 0 and mel_len > 0:
+                    code_seq = mc.reshape(-1)
+                    mel_codes_list.append(code_seq[-1:].reshape(1, 1).contiguous())
                 else:
-                    latent_list.append(_zero_latent)
+                    assert _zero_codes is not None
+                    mel_codes_list.append(_zero_codes)
 
-            req_meta: dict[str, Any] = {}
+                lat_acc = info_meta.get("latent_acc")
+                if isinstance(lat_acc, torch.Tensor) and lat_acc.numel() > 0 and mel_len > 0:
+                    lat_seq = lat_acc.reshape(-1, lat_acc.shape[-1]) if lat_acc.ndim != 2 else lat_acc
+                    idx = min(max(mel_len - 1, 0), int(lat_seq.shape[0]) - 1)
+                    latent_list.append(lat_seq[idx : idx + 1].contiguous())
+                else:
+                    hs = info.get("hidden_states", {})
+                    lat = hs.get("latent")
+                    if isinstance(lat, torch.Tensor) and lat.numel() > 0:
+                        lat_seq = lat.reshape(-1, lat.shape[-1]) if lat.ndim != 2 else lat
+                        latent_list.append(lat_seq[-1:].contiguous())
+                    else:
+                        assert _zero_latent is not None
+                        latent_list.append(_zero_latent)
+
+            # Scalar metadata is kept with REPLACE semantics by the generic
+            # full-payload accumulator. Emit the policy on every step so the
+            # final payload contract never depends on which decode row carried
+            # the one-time conditioning tensors.
+            req_meta: dict[str, Any] = {"use_gpt_latent": self.use_gpt_latent}
             if mel_len == 1:
                 s_ref = info_meta.get("S_ref")
                 ref_mel = info_meta.get("ref_mel")
                 style = info_meta.get("style")
+                req_meta["duration_factor"] = info_meta.get("duration_factor", 1.0)
                 if isinstance(s_ref, torch.Tensor):
                     req_meta["S_ref"] = s_ref
                 if isinstance(ref_mel, torch.Tensor):
@@ -363,13 +464,22 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
                     req_meta["style"] = style
             meta_list.append(req_meta)
 
-        if not any(t.numel() > 0 for t in mel_codes_list):
-            return OmniOutput(text_hidden_states=hidden, multimodal_outputs={})
-
-        mm: OmniPayload = {
-            "codes": {"mel": mel_codes_list},
-            "hidden_states": {"latent": latent_list},
-        }
+        if self.use_gpt_latent:
+            if not any(t.numel() > 0 for t in mel_codes_list):
+                return OmniOutput(text_hidden_states=hidden, multimodal_outputs={})
+            mm: OmniPayload = {
+                "codes": {"mel": mel_codes_list},
+            }
+            mm["hidden_states"] = {"latent": latent_list}
+        else:
+            # vLLM already materializes sampled token IDs on CPU for scheduler
+            # bookkeeping and stop-token handling. Stage 1 consumes the complete
+            # sequence only after request completion, so retain the conditioning
+            # metadata once and read the finished request.output_token_ids there
+            # instead of snapshotting a duplicate GPU code row every step.
+            if not any(meta_list):
+                return OmniOutput(text_hidden_states=hidden, multimodal_outputs={})
+            mm = {}
         if any(meta_list):
             mm["meta"] = meta_list
 
@@ -387,9 +497,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
     ) -> tuple[torch.Tensor, torch.Tensor, dict[str, Any]]:
         """Build prompt embeddings for prefill; compute mel embeddings for decode.
 
-        Prefill layout::
-
-            [conds(32) + emo_vec(1) + duration(2)] [text_emb + text_pos] [start_mel + mel_pos(0)]
+        IndexTTS 2 prefill uses 32 speaker latents plus two duration tokens.
+        IndexTTS 2.5 uses one CAMPPlus speaker token plus two zero tokens.
 
         Decode: ``mel_embedding(token) + mel_pos_embedding(step)``.
         """
@@ -453,6 +562,12 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             v = info_dict.get(key)
             return v[0] if isinstance(v, list) and v else default
 
+        duration_factor = float(_first("duration_factor", 1.0))
+        # Direct Omni callers bypass the serving adapter, so retain the
+        # model-side guard as the final fail-fast validation layer.
+        if not (INDEXTTS25_MIN_DURATION_FACTOR <= duration_factor <= INDEXTTS25_MAX_DURATION_FACTOR):
+            raise ValueError("IndexTTS 2.5 duration_factor must be between 0.5 and 2.0")
+
         text = _first("text")
         if not text:
             raise ValueError("Missing additional_information.text for IndexTTS2 talker.")
@@ -467,6 +582,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         emo_vector = _first("emo_vector")
         emo_alpha = float(_first("emo_alpha", 1.0))
         use_random = bool(_first("use_random", False))
+        lang = str(_first("lang", "zh"))
+        text_normalization = bool(_first("text_normalization", True))
         _raw_emo_voice = _first("emo_voice_name")
         emo_voice_name = str(_raw_emo_voice).strip().lower() if _raw_emo_voice else None
 
@@ -499,9 +616,19 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             self._ensure_w2v_stat_loaded(device)
             spk_cond_emb = wav2vec_extract(wav_16k, w2v_model, w2v_proc, device, self._w2v_stat)
 
-            semantic_codec = load_semantic_codec(self.model_path, self.config.semantic_codec, device)
-            with torch.no_grad():
-                _, s_ref = semantic_codec.quantize(spk_cond_emb)  # [B, T, 1024] quantized embeddings
+            if self.conditioning_policy.uses_campplus_projection:
+                # Official 2.5 keeps W2V-BERT features as the reference
+                # semantic sequence; EnhancedCodec is only used for generated
+                # semantic codes in Stage 1.
+                s_ref = spk_cond_emb
+            else:
+                semantic_codec = load_semantic_codec(
+                    self.model_path,
+                    self.config.semantic_codec,
+                    device,
+                )
+                with torch.no_grad():
+                    _, s_ref = semantic_codec.quantize(spk_cond_emb)
 
             campplus = load_campplus(self.model_path, device)
             fbank = compute_fbank(wav_16k, device)
@@ -521,12 +648,16 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
                     },
                 )
 
-        model_dtype = next(self.conditioning_encoder.parameters()).dtype
+        if self.conditioning_policy.uses_campplus_projection:
+            model_dtype = self.spk_emb_proj.weight.dtype
+        else:
+            model_dtype = next(self.conditioning_encoder.parameters()).dtype
         spk_cond_emb = spk_cond_emb.to(device=device, dtype=model_dtype)
-        spk_lens = torch.tensor([spk_cond_emb.shape[1]], device=device, dtype=torch.long)
-        speech_cond, mask = self.conditioning_encoder(spk_cond_emb, spk_lens)
-        conds_mask = self.cond_mask_pad(mask.squeeze(1))
-        conds = self.perceiver_encoder(speech_cond, conds_mask)  # [1, 32, D]
+        if self.conditioning_policy.uses_conformer_perceiver:
+            spk_lens = torch.tensor([spk_cond_emb.shape[1]], device=device, dtype=torch.long)
+            speech_cond, mask = self.conditioning_encoder(spk_cond_emb, spk_lens)
+            conds_mask = self.cond_mask_pad(mask.squeeze(1))
+            conds = self.perceiver_encoder(speech_cond, conds_mask)
 
         emo_vec = self._compute_emotion_vector(
             wav_16k=wav_16k,
@@ -546,19 +677,39 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             device=device,
         )
 
-        speed_zero = torch.zeros(1, device=device, dtype=torch.long)
-        speed_one = torch.ones(1, device=device, dtype=torch.long)
-        duration_emb = self.speed_emb(speed_zero)
-        duration_emb_half = self.speed_emb(speed_one)
+        if self.conditioning_policy.uses_campplus_projection:
+            speaker_token = self.spk_emb_proj(style.to(dtype=model_dtype)).unsqueeze(1)
+            zero_tokens = torch.zeros(
+                speaker_token.shape[0],
+                2,
+                self.model_dim,
+                device=device,
+                dtype=speaker_token.dtype,
+            )
+            conds_prefix = torch.cat(
+                [speaker_token + emo_vec.unsqueeze(1), zero_tokens],
+                dim=1,
+            )
+        else:
+            speed_zero = torch.zeros(1, device=device, dtype=torch.long)
+            speed_one = torch.ones(1, device=device, dtype=torch.long)
+            duration_emb = self.speed_emb(speed_zero)
+            duration_emb_half = self.speed_emb(speed_one)
+            conds_with_emo = conds + emo_vec.unsqueeze(1)
+            conds_prefix = torch.cat(
+                [conds_with_emo, duration_emb_half.unsqueeze(1), duration_emb.unsqueeze(1)],
+                dim=1,
+            )
 
-        conds_with_emo = conds + emo_vec.unsqueeze(1)  # [1, 32, D]
-        conds_prefix = torch.cat(
-            [conds_with_emo, duration_emb_half.unsqueeze(1), duration_emb.unsqueeze(1)],
-            dim=1,
-        )  # [1, 34, D]
-
-        text_tokens = self._tokenize_text(text, device)  # [1, L]
+        text_tokens, lang_id = self._tokenize_text(
+            text,
+            device,
+            lang=lang,
+            text_normalization=text_normalization,
+        )
         text_emb = self.text_embedding(text_tokens) + self.text_pos_embedding(text_tokens)
+        if lang_id is not None:
+            text_emb = text_emb + self.lang_embedding(lang_id).unsqueeze(1)
 
         start_mel = self.mel_embedding(torch.tensor([[self.start_mel_token]], device=device, dtype=torch.long))
         start_mel_pos = self.mel_pos_embedding.get_fixed_embedding(0, device)
@@ -567,13 +718,13 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         inputs_embeds = torch.cat([conds_prefix, text_emb, start_mel], dim=1).squeeze(0)
         mel_start_offset = int(conds_prefix.shape[1]) + int(text_emb.shape[1])
         prefill_mel_index = int(inputs_embeds.shape[0]) - 1
-
-        if int(inputs_embeds.shape[0]) < span_len:
-            pad_n = span_len - int(inputs_embeds.shape[0])
-            pad_emb = torch.zeros(pad_n, self.model_dim, device=device, dtype=inputs_embeds.dtype)
-            inputs_embeds = torch.cat([inputs_embeds, pad_emb], dim=0)
-        elif int(inputs_embeds.shape[0]) > span_len:
-            inputs_embeds = inputs_embeds[:span_len]
+        _require_exact_indextts_prefill_span(
+            actual_span_len=int(inputs_embeds.shape[0]),
+            scheduled_span_len=span_len,
+            model_type=str(getattr(self.config, "model_type", "indextts2")),
+            lang=lang,
+            text_token_count=int(text_tokens.shape[1]),
+        )
 
         input_ids_out = torch.full_like(input_ids, self.start_mel_token)
 
@@ -585,11 +736,26 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
                 "S_ref": s_ref.cpu().contiguous(),
                 "ref_mel": ref_mel.cpu().contiguous(),
                 "style": style.cpu().contiguous(),
-                "latent_acc": torch.zeros(0, self.model_dim, dtype=inputs_embeds.dtype, device=device),
+                "use_gpt_latent": self.use_gpt_latent,
+                "duration_factor": duration_factor,
             },
             "codes": {"mel": torch.zeros(0, dtype=torch.long, device=device)},
-            "hidden_states": {"latent": torch.zeros(0, self.model_dim, dtype=inputs_embeds.dtype, device=device)},
         }
+        if self.use_gpt_latent:
+            info_update["meta"]["latent_acc"] = torch.zeros(
+                0,
+                self.model_dim,
+                dtype=inputs_embeds.dtype,
+                device=device,
+            )
+            info_update["hidden_states"] = {
+                "latent": torch.zeros(
+                    0,
+                    self.model_dim,
+                    dtype=inputs_embeds.dtype,
+                    device=device,
+                )
+            }
 
         return input_ids_out, inputs_embeds, info_update
 
@@ -605,6 +771,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         reconstructs the complete latent sequence from per-step deltas emitted
         by make_omni_output.
         """
+        if not self.use_gpt_latent:
+            return {}
         if hidden_states.shape[0] != 1:
             meta = kwargs.get("meta", {})
             prefill_mel_index = int(meta.get("prefill_mel_index", hidden_states.shape[0] - 1))
@@ -665,6 +833,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             if emo_text is None:
                 emo_text = main_text
             emo_vector = self._predict_emotion_from_text(emo_text, device)
+            if emo_vector is None:
+                raise RuntimeError("IndexTTS use_emo_text requested but QwenEmotion could not be loaded")
         if use_emo_text or emo_vector is not None:
             emo_audio_path = None
 
@@ -840,7 +1010,7 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         self._ensure_matrix_loaded("_emo_matrix", "emo_matrix", "Emotion matrix")
         self._ensure_matrix_loaded("_spk_matrix", "spk_matrix", "Speaker matrix")
         if self._emo_matrix is None or self._spk_matrix is None:
-            return torch.zeros(1, self.model_dim, device=device)
+            raise RuntimeError("IndexTTS emotion control requires both emotion and speaker matrices")
 
         weight_vector = emo_dist.to(device=device, dtype=torch.float32)
         if weight_vector.ndim == 2:
@@ -886,23 +1056,47 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
     # Text tokenizer
     # ------------------------------------------------------------------
 
-    def _tokenize_text(self, text: str, device: torch.device) -> torch.Tensor:
-        """Tokenize text using the BPE tokenizer, add start/stop tokens."""
-        if self._text_tokenizer is None:
-            from .tokenizer import IndexTTS2Tokenizer
-
-            bpe_path = resolve_model_file(self.model_path, "bpe.model")
-            if bpe_path is None:
-                raise FileNotFoundError(f"BPE model not found in {self.model_path}")
-            self._text_tokenizer = IndexTTS2Tokenizer(bpe_path, model_dir=self.model_path)
-
-        token_ids = self._text_tokenizer.encode(text, add_special_tokens=False)
-
-        # Wrap with start/stop text tokens
+    def _tokenize_text(
+        self,
+        text: str,
+        device: torch.device,
+        *,
+        lang: str = "zh",
+        text_normalization: bool = True,
+    ) -> tuple[torch.Tensor, torch.Tensor | None]:
+        """Tokenize text and add the checkpoint start/stop text tokens."""
         start_text = 0
         stop_text = 1
+        lang_id: int | None = None
+        if self.conditioning_policy.uses_language_embedding:
+            from .text_processing_v2_5 import prepare_indextts25_text
+
+            token_ids, lang_id = prepare_indextts25_text(
+                text,
+                lang=lang,
+                model_dir=self.model_path,
+                tokenizer_file=self.config.tokenizer_file,
+                text_normalization=text_normalization,
+            )
+            token_ids = [token_id for token_id in token_ids if token_id not in {start_text, stop_text}]
+        else:
+            if self._text_tokenizer is None:
+                from .tokenizer import IndexTTS2Tokenizer
+
+                bpe_path = resolve_model_file(self.model_path, "bpe.model")
+                if bpe_path is None:
+                    raise FileNotFoundError(f"BPE model not found in {self.model_path}")
+                self._text_tokenizer = IndexTTS2Tokenizer(bpe_path, model_dir=self.model_path)
+
+            token_ids = self._text_tokenizer.encode(text, add_special_tokens=False)
+
+        # The 2.5 tokenizer begins with the explicit ``<|lang|>`` token.
+        # Official prepare_gpt_inputs filters any existing wrapper tokens,
+        # then adds start_text=0 and stop_text=1 around that tokenizer output.
         token_ids = [start_text] + token_ids + [stop_text]
-        return torch.tensor([token_ids], device=device, dtype=torch.long)
+        token_tensor = torch.tensor([token_ids], device=device, dtype=torch.long)
+        lang_tensor = torch.tensor([lang_id], device=device, dtype=torch.long) if lang_id is not None else None
+        return token_tensor, lang_tensor
 
     # ------------------------------------------------------------------
     # Lazy loading helpers
@@ -919,7 +1113,7 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             else:
                 self._w2v_stat = raw
         else:
-            logger.warning("Wav2Vec2-BERT stat file not found in %s", self.model_path)
+            raise FileNotFoundError(f"Wav2Vec2-BERT stat file not found in {self.model_path!r}")
 
     def _ensure_matrix_loaded(self, attr: str, cfg_key: str, label: str) -> None:
         if getattr(self, attr) is not None:
@@ -929,7 +1123,7 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             raw = torch.load(path, map_location="cpu", weights_only=True)
             setattr(self, attr, torch.split(raw, list(self.config.emo_num)))
         else:
-            logger.warning("%s not found in %s", label, self.model_path)
+            raise FileNotFoundError(f"{label} not found in {self.model_path!r}")
 
     # ------------------------------------------------------------------
     # Weight loading
@@ -966,7 +1160,8 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         params_dict = dict(self.named_parameters(remove_duplicate=False))
         loaded_params: set[str] = set()
 
-        for name, loaded_weight in state.items():
+        for checkpoint_name, loaded_weight in state.items():
+            name = _normalize_indextts_checkpoint_key(checkpoint_name)
             # Skip attention masks
             if ".attn.bias" in name or ".attn.masked_bias" in name:
                 continue
@@ -989,7 +1184,11 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
                 continue
 
             if mapped_name not in params_dict:
-                logger.debug("Skipping unrecognized weight: %s → %s", name, mapped_name)
+                logger.debug(
+                    "Skipping unrecognized weight: %s → %s",
+                    checkpoint_name,
+                    mapped_name,
+                )
                 continue
 
             param = params_dict[mapped_name]
@@ -1015,17 +1214,29 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
             "mel_embedding.",
             "text_pos_embedding.",
             "mel_pos_embedding.",
-            "speed_emb.",
             "emo_layer.",
             "emovec_layer.",
-            "conditioning_encoder.",
-            "perceiver_encoder.",
             "emo_conditioning_encoder.",
             "emo_perceiver_encoder.",
             "h.",
             "ln_f.",
             "final_norm.",
         ]
+        if self.conditioning_policy.uses_campplus_projection:
+            required_prefixes.extend(
+                [
+                    "spk_emb_proj.",
+                    "lang_embedding.",
+                ]
+            )
+        else:
+            required_prefixes.extend(
+                [
+                    "speed_emb.",
+                    "conditioning_encoder.",
+                    "perceiver_encoder.",
+                ]
+            )
         if self.mel_head is not None:
             required_prefixes.append("mel_head.")
         missing_prefixes = [
@@ -1033,18 +1244,22 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         ]
         if missing_prefixes:
             raise RuntimeError(
-                "IndexTTS2 GPT checkpoint did not load required parameter groups: " + ", ".join(missing_prefixes)
+                f"{self.config.model_type} GPT checkpoint did not load required parameter groups: "
+                + ", ".join(missing_prefixes)
             )
 
         # Ensure all sub-modules on correct device (some nn.Parameter created
         # with torch.Tensor() end up on CPU even when model is on CUDA).
         target_device = next((p.device for p in self.h.parameters()), torch.device("cpu"))
-        for mod in [
-            self.conditioning_encoder,
+        modules = [
             self.emo_conditioning_encoder,
-            self.perceiver_encoder,
             self.emo_perceiver_encoder,
-        ]:
+        ]
+        if self.conditioning_policy.uses_campplus_projection:
+            modules.extend([self.spk_emb_proj, self.lang_embedding])
+        else:
+            modules.extend([self.conditioning_encoder, self.perceiver_encoder])
+        for mod in modules:
             mod.to(target_device)
 
         self._warmup_external_models(target_device)
@@ -1054,9 +1269,17 @@ class IndexTTS2TalkerForConditionalGeneration(nn.Module):
         """Preload external models to eliminate first-request latency."""
         try:
             load_wav2vec2(self.model_path, device)
-            load_semantic_codec(self.model_path, self.config.semantic_codec, device)
+            if not self.conditioning_policy.uses_campplus_projection:
+                load_semantic_codec(
+                    self.model_path,
+                    self.config.semantic_codec,
+                    device,
+                )
             load_campplus(self.model_path, device)
             self._ensure_w2v_stat_loaded(device)
-            logger.info("External models preloaded: Wav2Vec2, RepCodec, CAMPPlus")
+            logger.info(
+                "External models preloaded: Wav2Vec2, %sCAMPPlus",
+                "RepCodec, " if not self.conditioning_policy.uses_campplus_projection else "",
+            )
         except Exception as e:
-            logger.warning("Failed to preload external models: %s", e)
+            raise RuntimeError("Failed to preload required IndexTTS Stage 0 models") from e
diff --git a/vllm_omni/model_executor/models/indextts2/pipeline.py b/vllm_omni/model_executor/models/indextts2/pipeline.py
index 50f866ffd..e29d61563 100644
--- a/vllm_omni/model_executor/models/indextts2/pipeline.py
+++ b/vllm_omni/model_executor/models/indextts2/pipeline.py
@@ -43,7 +43,43 @@ INDEXTTS2_PIPELINE = PipelineConfig(
             engine_output_type="audio",
             model_arch="IndexTTS2S2MelDecoder",
             sync_process_input_func=f"{_PROC}.talker2s2mel_token_only",
-            extras={"skip_tokenizer_init": True, "tokenizer": "gpt2"},
+            extras={"skip_tokenizer_init": True},
+            sampling_constraints={"detokenize": True},
+        ),
+    ),
+)
+
+
+INDEXTTS25_PIPELINE = PipelineConfig(
+    model_type="indextts2_5",
+    default_deploy_config_name="indextts2_5.yaml",
+    model_arch="IndexTTS25TalkerForConditionalGeneration",
+    stages=(
+        StagePipelineConfig(
+            stage_id=0,
+            model_stage="indextts2_5_talker",
+            execution_type=StageExecutionType.LLM_AR,
+            input_sources=(),
+            owns_tokenizer=True,
+            engine_output_type="latent",
+            extras={"skip_tokenizer_init": True},
+            custom_process_next_stage_input_func=f"{_PROC}.talker2s2mel_full_payload",
+            sampling_constraints={
+                "detokenize": False,
+                "stop_token_ids": [8193],
+            },
+        ),
+        StagePipelineConfig(
+            stage_id=1,
+            model_stage="indextts2_5_s2mel_decoder",
+            execution_type=StageExecutionType.LLM_GENERATION,
+            input_sources=(0,),
+            final_output=True,
+            final_output_type="audio",
+            engine_output_type="audio",
+            model_arch="IndexTTS25S2MelDecoder",
+            sync_process_input_func=f"{_PROC}.talker2s2mel_token_only",
+            extras={"skip_tokenizer_init": True},
             sampling_constraints={"detokenize": True},
         ),
     ),
diff --git a/vllm_omni/model_executor/models/indextts2/preprocess_utils.py b/vllm_omni/model_executor/models/indextts2/preprocess_utils.py
index 452bce9bb..1b6fa9485 100644
--- a/vllm_omni/model_executor/models/indextts2/preprocess_utils.py
+++ b/vllm_omni/model_executor/models/indextts2/preprocess_utils.py
@@ -22,7 +22,7 @@ logger = init_logger(__name__)
 # ---------------------------------------------------------------------------
 
 _wav2vec2_cache: dict[tuple[str, str], tuple] = {}
-_semantic_codec_cache: dict[tuple[str, str], Any] = {}
+_semantic_codec_cache: dict[tuple[str, str, str], Any] = {}
 _campplus_cache: dict[tuple[str, str], Any] = {}
 _qwen_emotion_cache: dict[tuple[str, str], tuple] = {}
 
@@ -34,11 +34,40 @@ def _freeze(model):
     return model
 
 
+def local_model_roots(model_path: str) -> tuple[str, ...]:
+    """Return native IndexTTS asset roots in lookup order.
+
+    HuggingFace-converted checkpoints place assets at the model root, while
+    the official IndexTTS repository and lab-published bundle keep them under
+    ``checkpoints/``.
+    """
+    roots = [model_path]
+    checkpoints = os.path.join(model_path, "checkpoints")
+    if os.path.isdir(checkpoints):
+        roots.append(checkpoints)
+    return tuple(roots)
+
+
+def resolve_model_directory(
+    model_path: str,
+    *relative_paths: str,
+) -> str | None:
+    for root in local_model_roots(model_path):
+        for relative_path in relative_paths:
+            candidate = os.path.join(root, relative_path)
+            if os.path.isdir(candidate):
+                return candidate
+    return None
+
+
 def resolve_model_file(model_path: str, filename: str) -> str | None:
     """Resolve an IndexTTS2 asset from a local model dir or HF repo id."""
-    local_path = os.path.join(model_path, filename)
-    if os.path.isfile(local_path):
-        return local_path
+    for root in local_model_roots(model_path):
+        local_path = os.path.join(root, filename)
+        if os.path.isfile(local_path):
+            return local_path
+    if os.path.isdir(model_path):
+        return None
     try:
         return cached_file(model_path, filename)
     except Exception as e:
@@ -53,11 +82,38 @@ def load_wav2vec2(model_path: str, device: torch.device):
     from transformers import AutoFeatureExtractor, Wav2Vec2BertModel
 
     model, processor = None, None
-    # Try local subfolder first (no lock needed), then HF hub with lock.
+    # Try the layouts shipped by IndexTTS 2 and 2.5 before the Hub fallback.
+    local_dir = resolve_model_directory(
+        model_path,
+        "wav2vec2bert",
+        "w2v-bert-2.0",
+        os.path.join("hf_cache", "w2v-bert-2.0"),
+    )
+    if local_dir is not None:
+        try:
+            processor = AutoFeatureExtractor.from_pretrained(
+                local_dir,
+                local_files_only=True,
+            )
+            model = Wav2Vec2BertModel.from_pretrained(
+                local_dir,
+                local_files_only=True,
+            )
+        except Exception as exc:
+            raise RuntimeError(f"Failed to load local IndexTTS Wav2Vec2-BERT assets from {local_dir!r}") from exc
+
+    if local_dir is None and os.path.isdir(model_path):
+        raise FileNotFoundError(f"IndexTTS Wav2Vec2-BERT assets are missing from local bundle {model_path!r}")
+
+    # Try a remote model subfolder, then the public base model.
     try:
-        src_args = dict(pretrained_model_name_or_path=model_path, subfolder="wav2vec2bert")
-        processor = AutoFeatureExtractor.from_pretrained(**src_args)
-        model = Wav2Vec2BertModel.from_pretrained(**src_args)
+        if model is None or processor is None:
+            src_args = dict(
+                pretrained_model_name_or_path=model_path,
+                subfolder="wav2vec2bert",
+            )
+            processor = AutoFeatureExtractor.from_pretrained(**src_args)
+            model = Wav2Vec2BertModel.from_pretrained(**src_args)
     except Exception:
         try:
             with _repo_prefetch_lock("facebook/w2v-bert-2.0"):
@@ -67,16 +123,43 @@ def load_wav2vec2(model_path: str, device: torch.device):
         except Exception:
             pass
     if model is None or processor is None:
-        raise RuntimeError(f"Could not load Wav2Vec2-BERT from {model_path}/wav2vec2bert or facebook/w2v-bert-2.0")
+        raise RuntimeError(
+            f"Could not load Wav2Vec2-BERT from IndexTTS model assets under {model_path!r} or facebook/w2v-bert-2.0"
+        )
     _freeze(model.to(device=device, dtype=torch.float32))
     _wav2vec2_cache[cache_key] = (model, processor)
     return model, processor
 
 
-def load_semantic_codec(model_path: str, config: dict, device: torch.device):
-    cache_key = (model_path, str(device))
+def load_semantic_codec(
+    model_path: str,
+    config: dict,
+    device: torch.device,
+    *,
+    codec_type: str = "repcodec",
+    checkpoint_name: str | None = None,
+):
+    cache_key = (model_path, str(device), codec_type)
     if cache_key in _semantic_codec_cache:
         return _semantic_codec_cache[cache_key]
+
+    if codec_type == "enhanced":
+        from .codec import EnhancedCodec
+
+        codec = EnhancedCodec(**config, cfg=config)
+        checkpoint_name = checkpoint_name or "codec.pth"
+        ckpt_path = resolve_model_file(model_path, checkpoint_name)
+        if ckpt_path is None:
+            raise FileNotFoundError(
+                f"IndexTTS 2.5 EnhancedCodec checkpoint {checkpoint_name!r} not found in {model_path!r}"
+            )
+        codec.load_checkpoint(ckpt_path)
+        _freeze(codec.to(device=device, dtype=torch.float32))
+        _semantic_codec_cache[cache_key] = codec
+        return codec
+    if codec_type != "repcodec":
+        raise ValueError(f"Unsupported IndexTTS semantic codec type: {codec_type!r}")
+
     from .utils.maskgct.repcodec_model import RepCodec
 
     codec = RepCodec(
@@ -84,11 +167,14 @@ def load_semantic_codec(model_path: str, config: dict, device: torch.device):
         hidden_size=config.get("hidden_size", 1024),
         codebook_dim=config.get("codebook_dim", 8),
     )
-    ckpt_path = resolve_model_file(model_path, "semantic_codec.pth")
+    checkpoint_name = checkpoint_name or "semantic_codec.pth"
+    ckpt_path = resolve_model_file(model_path, checkpoint_name)
     if ckpt_path is not None:
         state = torch.load(ckpt_path, map_location="cpu", weights_only=True)
         codec.load_state_dict(state, strict=False)
     else:
+        if os.path.isdir(model_path):
+            raise FileNotFoundError(f"IndexTTS RepCodec checkpoint is missing from local bundle {model_path!r}")
         import safetensors.torch
         from huggingface_hub import hf_hub_download
 
@@ -106,8 +192,19 @@ def load_campplus(model_path: str, device: torch.device):
     from .utils.campplus.dtdnn import CAMPPlus
 
     campplus = CAMPPlus(feat_dim=80, embedding_size=192)
-    ckpt_path = resolve_model_file(model_path, "campplus.pth")
+    ckpt_path = None
+    for relative_path in (
+        "campplus.pth",
+        "campplus_cn_common.bin",
+        os.path.join("hf_cache", "campplus_cn_common.bin"),
+        os.path.join("campplus", "campplus_cn_common.bin"),
+    ):
+        ckpt_path = resolve_model_file(model_path, relative_path)
+        if ckpt_path is not None:
+            break
     if ckpt_path is None:
+        if os.path.isdir(model_path):
+            raise FileNotFoundError(f"IndexTTS CAMPPlus checkpoint is missing from local bundle {model_path!r}")
         from huggingface_hub import hf_hub_download
 
         ckpt_path = hf_hub_download("funasr/campplus", filename="campplus_cn_common.bin")
@@ -125,20 +222,29 @@ def load_qwen_emotion(model_path: str, device: torch.device, *, trust_remote_cod
     from transformers import AutoModelForCausalLM, AutoTokenizer
 
     subfolder = "qwen0.6bemo4-merge"
+    local_dir = resolve_model_directory(model_path, subfolder)
+    source_args = (
+        {"pretrained_model_name_or_path": local_dir, "local_files_only": True}
+        if local_dir is not None
+        else {
+            "pretrained_model_name_or_path": model_path,
+            "subfolder": subfolder,
+        }
+    )
     try:
         tokenizer = AutoTokenizer.from_pretrained(
-            model_path,
-            subfolder=subfolder,
+            **source_args,
             trust_remote_code=trust_remote_code,
         )
         model = AutoModelForCausalLM.from_pretrained(
-            model_path,
-            subfolder=subfolder,
+            **source_args,
             torch_dtype="float16",
             device_map={"": str(device)},
             trust_remote_code=trust_remote_code,
         )
     except Exception as e:
+        if local_dir is not None:
+            raise RuntimeError(f"Failed to load local IndexTTS QwenEmotion assets from {local_dir!r}") from e
         logger.warning(
             "Could not load QwenEmotion from %s/%s: %s. use_emo_text will fall back to default emotion.",
             model_path,
@@ -172,9 +278,8 @@ def compute_fbank(wav_16k: torch.Tensor, device: torch.device) -> torch.Tensor:
         )
         fbank = fbank - fbank.mean(dim=0, keepdim=True)
         return fbank.unsqueeze(0).to(device=device)  # [1, T, 80]
-    except (ImportError, RuntimeError, OSError):
-        logger.warning("torchaudio not available, returning zero fbank")
-        return torch.zeros(1, 100, 80, device=device)
+    except (ImportError, RuntimeError, OSError) as exc:
+        raise RuntimeError("IndexTTS requires torchaudio Kaldi fbank support") from exc
 
 
 def wav2vec_extract(
diff --git a/vllm_omni/model_executor/models/indextts2/prompt_utils.py b/vllm_omni/model_executor/models/indextts2/prompt_utils.py
index c33202785..5a950036a 100644
--- a/vllm_omni/model_executor/models/indextts2/prompt_utils.py
+++ b/vllm_omni/model_executor/models/indextts2/prompt_utils.py
@@ -7,10 +7,19 @@ from __future__ import annotations
 from functools import lru_cache
 
 from vllm_omni.model_executor.models.indextts2.preprocess_utils import resolve_model_file
+from vllm_omni.model_executor.models.indextts2.text_processing_v2_5 import (
+    prepare_indextts25_text,
+)
 from vllm_omni.model_executor.models.indextts2.tokenizer import IndexTTS2Tokenizer
+from vllm_omni.model_executor.models.indextts2.tokenizer_v2_5 import (
+    INDEXTTS25_TOKENIZER_FILE,
+)
 
-_CONDITIONING_PREFIX_TOKENS = 34
-_TEXT_WRAPPER_TOKENS = 2
+_V2_CONDITIONING_PREFIX_TOKENS = 34
+_V25_CONDITIONING_PREFIX_TOKENS = 3
+_V2_TEXT_WRAPPER_TOKENS = 2
+_V25_TEXT_WRAPPER_TOKENS = 2
+_V25_TEXT_WRAPPER_TOKEN_IDS = frozenset({0, 1})
 _START_MEL_TOKENS = 1
 
 
@@ -26,22 +35,55 @@ def _get_text_tokenizer(model_id_or_path: str) -> IndexTTS2Tokenizer:
     return IndexTTS2Tokenizer(_resolve_bpe_model_path(model_id_or_path), model_dir=model_id_or_path)
 
 
-def estimate_indextts2_prefill_prompt_len(model_id_or_path: str, text: str) -> int:
+def estimate_indextts2_prefill_prompt_len(
+    model_id_or_path: str,
+    text: str,
+    *,
+    model_type: str = "indextts2",
+    lang: str = "zh",
+    text_normalization: bool = True,
+    tokenizer_file: str = INDEXTTS25_TOKENIZER_FILE,
+) -> int:
     """Return the placeholder prompt length expected by the IndexTTS2 talker.
 
-    The model-side prefill replaces placeholder embeddings with:
-    34 conditioning tokens, text tokens wrapped with start/stop markers, and
-    one start-mel token.
+    IndexTTS 2 uses 34 conditioning tokens. IndexTTS 2.5 uses one projected
+    CAMPPlus speaker token followed by two zero tokens.
     """
-    tokenizer = _get_text_tokenizer(model_id_or_path)
-    text_token_count = len(tokenizer.encode(text, add_special_tokens=False)) + _TEXT_WRAPPER_TOKENS
-    return _CONDITIONING_PREFIX_TOKENS + text_token_count + _START_MEL_TOKENS
+    if model_type == "indextts2_5":
+        text_ids, _ = prepare_indextts25_text(
+            text,
+            lang=lang,
+            model_dir=model_id_or_path,
+            text_normalization=text_normalization,
+            tokenizer_file=tokenizer_file,
+        )
+        conditioning_prefix_tokens = _V25_CONDITIONING_PREFIX_TOKENS
+        text_token_count = (
+            sum(token_id not in _V25_TEXT_WRAPPER_TOKEN_IDS for token_id in text_ids) + _V25_TEXT_WRAPPER_TOKENS
+        )
+    else:
+        tokenizer = _get_text_tokenizer(model_id_or_path)
+        text_token_count = len(tokenizer.encode(text, add_special_tokens=False)) + _V2_TEXT_WRAPPER_TOKENS
+        conditioning_prefix_tokens = _V2_CONDITIONING_PREFIX_TOKENS
+    return conditioning_prefix_tokens + text_token_count + _START_MEL_TOKENS
 
 
 def build_indextts2_prefill_prompt_ids(
     model_id_or_path: str,
     text: str,
     *,
+    model_type: str = "indextts2",
+    lang: str = "zh",
+    text_normalization: bool = True,
+    tokenizer_file: str = INDEXTTS25_TOKENIZER_FILE,
     placeholder_token_id: int = 1,
 ) -> list[int]:
-    return [placeholder_token_id] * estimate_indextts2_prefill_prompt_len(model_id_or_path, text)
+    prompt_len = estimate_indextts2_prefill_prompt_len(
+        model_id_or_path,
+        text,
+        model_type=model_type,
+        lang=lang,
+        text_normalization=text_normalization,
+        tokenizer_file=tokenizer_file,
+    )
+    return [placeholder_token_id] * prompt_len
diff --git a/vllm_omni/model_executor/models/indextts2/s2mel/modules/commons.py b/vllm_omni/model_executor/models/indextts2/s2mel/modules/commons.py
index dd86f5847..8aed5f93b 100644
--- a/vllm_omni/model_executor/models/indextts2/s2mel/modules/commons.py
+++ b/vllm_omni/model_executor/models/indextts2/s2mel/modules/commons.py
@@ -68,6 +68,6 @@ class MyModel(nn.Module):
         x = self.models["gpt_layer"](x)
         return x
 
-    def enable_torch_compile(self):
+    def enable_torch_compile(self, mode: str = "default"):
         if "cfm" in self.models:
-            self.models["cfm"].enable_torch_compile()
+            self.models["cfm"].enable_torch_compile(mode=mode)
diff --git a/vllm_omni/model_executor/models/indextts2/s2mel/modules/diffusion_transformer.py b/vllm_omni/model_executor/models/indextts2/s2mel/modules/diffusion_transformer.py
index f73fdc800..a76d998a4 100644
--- a/vllm_omni/model_executor/models/indextts2/s2mel/modules/diffusion_transformer.py
+++ b/vllm_omni/model_executor/models/indextts2/s2mel/modules/diffusion_transformer.py
@@ -163,7 +163,18 @@ class DiT(torch.nn.Module):
     def setup_caches(self, max_batch_size, max_seq_length):
         self.transformer.setup_caches(max_batch_size, max_seq_length, use_kv_cache=False)
 
-    def forward(self, x, prompt_x, x_lens, t, style, cond, mask_content=False, pre_mask=None):
+    def forward(
+        self,
+        x,
+        prompt_x,
+        x_lens,
+        t,
+        style,
+        cond,
+        mask_content=False,
+        pre_mask=None,
+        unpad_data: tuple[torch.Tensor, torch.Tensor] | None = None,
+    ):
         """
         x (torch.Tensor): random noise
         prompt_x (torch.Tensor): reference mel + zero mel
@@ -226,10 +237,16 @@ class DiT(torch.nn.Module):
         input_pos = self.input_pos[: x_in.size(1)]  # (T,) range（0，1863）
         # Route through per-shape CUDA graph runner if enabled.
         graph_runner = getattr(self, "_cuda_graph_runner", None)
-        if graph_runner is not None:
+        if graph_runner is not None and unpad_data is None:
             x_res = graph_runner(x_in, t1.unsqueeze(1), input_pos, x_mask_expanded)
         else:
-            x_res = self.transformer(x_in, t1.unsqueeze(1), input_pos, x_mask_expanded)  # [2, 1863, 512]
+            x_res = self.transformer(
+                x_in,
+                t1.unsqueeze(1),
+                input_pos,
+                x_mask_expanded,
+                unpad_data=unpad_data,
+            )  # [2, 1863, 512]
         x_res = x_res[:, 1:] if self.time_as_token else x_res
         x_res = x_res[:, 1:] if self.style_as_token else x_res
 
diff --git a/vllm_omni/model_executor/models/indextts2/s2mel/modules/flow_matching.py b/vllm_omni/model_executor/models/indextts2/s2mel/modules/flow_matching.py
index 5192867af..32c2f641c 100644
--- a/vllm_omni/model_executor/models/indextts2/s2mel/modules/flow_matching.py
+++ b/vllm_omni/model_executor/models/indextts2/s2mel/modules/flow_matching.py
@@ -8,6 +8,41 @@ import torch
 from vllm_omni.model_executor.models.indextts2.s2mel.modules.diffusion_transformer import DiT
 
 
+def build_cfm_unpad_data(
+    lengths: list[int],
+    *,
+    padded_length: int,
+    token_offset: int,
+    repeat_for_cfg: bool,
+    device: torch.device,
+) -> tuple[torch.Tensor, torch.Tensor]:
+    """Build row-major FlashAttention unpadding metadata for one CFM group."""
+    if not lengths:
+        raise ValueError("CFM unpad data requires at least one sequence length")
+    if token_offset < 0:
+        raise ValueError(f"CFM unpad token offset must be non-negative: {token_offset}")
+    if any(length < 0 or length > padded_length for length in lengths):
+        raise ValueError(f"CFM unpad lengths out of range: lengths={lengths} padded={padded_length}")
+    if max(lengths) != padded_length:
+        raise ValueError(f"CFM unpad group must contain its padded max: lengths={lengths} padded={padded_length}")
+
+    valid_lengths = [length + token_offset for length in lengths]
+    if repeat_for_cfg:
+        valid_lengths = [*valid_lengths, *valid_lengths]
+    padded_stride = padded_length + token_offset
+    indices = torch.cat(
+        [
+            torch.arange(valid_length, device=device, dtype=torch.int64) + row * padded_stride
+            for row, valid_length in enumerate(valid_lengths)
+        ]
+    )
+    cumulative_lengths = [0]
+    for valid_length in valid_lengths:
+        cumulative_lengths.append(cumulative_lengths[-1] + valid_length)
+    cu_seqlens = torch.tensor(cumulative_lengths, device=device, dtype=torch.int32)
+    return indices, cu_seqlens
+
+
 class BASECFM(torch.nn.Module, ABC):
     def __init__(
         self,
@@ -26,7 +61,20 @@ class BASECFM(torch.nn.Module, ABC):
             self.zero_prompt_speech_token = False
 
     @torch.inference_mode()
-    def inference(self, mu, x_lens, prompt, style, f0, n_timesteps, temperature=1.0, inference_cfg_rate=0.5):
+    def inference(
+        self,
+        mu,
+        x_lens,
+        prompt,
+        style,
+        f0,
+        n_timesteps,
+        temperature=1.0,
+        inference_cfg_rate=0.5,
+        initial_noise=None,
+        prompt_lens=None,
+        unpad_data: tuple[torch.Tensor, torch.Tensor] | None = None,
+    ):
         """Forward diffusion
 
         Args:
@@ -47,11 +95,48 @@ class BASECFM(torch.nn.Module, ABC):
                 shape: (batch_size, 80, mel_timesteps)
         """
         B, T = mu.size(0), mu.size(1)
-        z = torch.randn([B, self.in_channels, T], device=mu.device, dtype=mu.dtype) * temperature
+        expected_noise_shape = (B, self.in_channels, T)
+        if initial_noise is None:
+            z = torch.randn(
+                expected_noise_shape,
+                device=mu.device,
+                dtype=mu.dtype,
+            )
+        else:
+            if tuple(initial_noise.shape) != expected_noise_shape:
+                raise ValueError(
+                    "CFM initial noise shape mismatch: "
+                    f"expected={expected_noise_shape}, got={tuple(initial_noise.shape)}"
+                )
+            z = initial_noise.to(device=mu.device, dtype=mu.dtype)
+        z = z * temperature
         t_span = torch.linspace(0, 1, n_timesteps + 1, device=mu.device, dtype=mu.dtype)
-        return self.solve_euler(z, x_lens, prompt, mu, style, f0, t_span, inference_cfg_rate)
+        return self.solve_euler(
+            z,
+            x_lens,
+            prompt,
+            mu,
+            style,
+            f0,
+            t_span,
+            inference_cfg_rate,
+            prompt_lens=prompt_lens,
+            unpad_data=unpad_data,
+        )
 
-    def solve_euler(self, x, x_lens, prompt, mu, style, f0, t_span, inference_cfg_rate=0.5):
+    def solve_euler(
+        self,
+        x,
+        x_lens,
+        prompt,
+        mu,
+        style,
+        f0,
+        t_span,
+        inference_cfg_rate=0.5,
+        prompt_lens=None,
+        unpad_data: tuple[torch.Tensor, torch.Tensor] | None = None,
+    ):
         """
         Fixed euler solver for ODEs.
         Args:
@@ -82,19 +167,35 @@ class BASECFM(torch.nn.Module, ABC):
                 out = self.estimator(*args, **kw)
             return out.float()
 
-        prompt_len = prompt.size(-1)
+        batch = x.shape[0]
+        if prompt_lens is None:
+            prompt_lens = torch.full(
+                (batch,),
+                prompt.size(-1),
+                device=x.device,
+                dtype=torch.long,
+            )
+        else:
+            prompt_lens = prompt_lens.to(device=x.device, dtype=torch.long).reshape(-1)
+            if prompt_lens.shape != (batch,):
+                raise ValueError(f"CFM prompt length/batch mismatch: lengths={prompt_lens.numel()} batch={batch}")
+
+        prompt_positions = torch.arange(prompt.size(-1), device=x.device)
+        prompt_mask = prompt_positions.unsqueeze(0) < prompt_lens.unsqueeze(1)
+        x_positions = torch.arange(x.size(-1), device=x.device)
+        noise_prefix_mask = x_positions.unsqueeze(0) < prompt_lens.unsqueeze(1)
+
         prompt_x = torch.zeros_like(x)
-        prompt_x[..., :prompt_len] = prompt[..., :prompt_len]
-        x[..., :prompt_len] = 0
+        prompt_x[..., : prompt.size(-1)] = prompt * prompt_mask.unsqueeze(1).to(prompt.dtype)
+        x.masked_fill_(noise_prefix_mask.unsqueeze(1), 0)
         if self.zero_prompt_speech_token:
-            mu[..., :prompt_len] = 0
+            mu = mu.masked_fill(noise_prefix_mask.unsqueeze(-1), 0)
 
         # Precompute mask once — T and x_lens are constant across all ODE steps.
         # x_mask [B, 1, T] broadcasts to [2B, 1, T] when CFG doubles batch.
         pre_mask = self._precompute_mask(x, x_lens)
 
         if inference_cfg_rate > 0:
-            batch = x.shape[0]
             cfg_prompt_x = prompt_x.new_zeros((2 * batch, *prompt_x.shape[1:]))
             cfg_prompt_x[:batch].copy_(prompt_x)
             cfg_style = style.new_zeros((2 * batch, *style.shape[1:]))
@@ -120,16 +221,26 @@ class BASECFM(torch.nn.Module, ABC):
                     cfg_style,
                     cfg_mu,
                     pre_mask=cfg_pre_mask,
+                    unpad_data=unpad_data,
                 )
 
                 dphi_dt, cfg_dphi_dt = stacked_dphi_dt.chunk(2, dim=0)
                 dphi_dt = (1.0 + inference_cfg_rate) * dphi_dt - inference_cfg_rate * cfg_dphi_dt
             else:
-                dphi_dt = _run_estimator(x, prompt_x, x_lens, t.unsqueeze(0), style, mu, pre_mask=pre_mask)
+                dphi_dt = _run_estimator(
+                    x,
+                    prompt_x,
+                    x_lens,
+                    t.unsqueeze(0),
+                    style,
+                    mu,
+                    pre_mask=pre_mask,
+                    unpad_data=unpad_data,
+                )
 
             x = x + dt * dphi_dt
             t = t + dt
-            x[:, :, :prompt_len] = 0
+            x.masked_fill_(noise_prefix_mask.unsqueeze(1), 0)
 
         return x
 
@@ -180,7 +291,7 @@ class CFM(BASECFM):
             raise NotImplementedError(f"Unknown diffusion type {args.dit_type}")
         self._compiled = False
 
-    def enable_torch_compile(self):
+    def enable_torch_compile(self, mode: str = "default"):
         """Enable torch.compile optimization for the estimator model.
 
         This method applies torch.compile to the estimator (DiT model) for significant
@@ -191,6 +302,7 @@ class CFM(BASECFM):
             torch._inductor.config.reorder_for_compute_comm_overlap = True
         self.estimator = torch.compile(
             self._eager_estimator,
+            mode=mode,
             fullgraph=True,
             dynamic=True,
         )
diff --git a/vllm_omni/model_executor/models/indextts2/s2mel/modules/gpt_fast/model.py b/vllm_omni/model_executor/models/indextts2/s2mel/modules/gpt_fast/model.py
index c410b6387..0e5b071d1 100644
--- a/vllm_omni/model_executor/models/indextts2/s2mel/modules/gpt_fast/model.py
+++ b/vllm_omni/model_executor/models/indextts2/s2mel/modules/gpt_fast/model.py
@@ -116,6 +116,7 @@ class Transformer(nn.Module):
         context: Tensor | None = None,
         context_input_pos: Tensor | None = None,
         cross_attention_mask: Tensor | None = None,
+        unpad_data: tuple[Tensor, Tensor] | None = None,
     ) -> Tensor:
         assert self.freqs_cis is not None, "Caches must be initialized first"
         if mask is None:  # in case of non-causal model
@@ -135,7 +136,18 @@ class Transformer(nn.Module):
                 skip_in_x = skip_in_x_list.pop(-1)
             else:
                 skip_in_x = None
-            x = layer(x, c, input_pos, freqs_cis, mask, context, context_freqs_cis, cross_attention_mask, skip_in_x)
+            x = layer(
+                x,
+                c,
+                input_pos,
+                freqs_cis,
+                mask,
+                context,
+                context_freqs_cis,
+                cross_attention_mask,
+                skip_in_x,
+                unpad_data=unpad_data,
+            )
             if self.uvit_skip_connection and i in self.layers_emit_skip:
                 skip_in_x_list.append(x)
         x = self.norm(x, c)
@@ -169,11 +181,18 @@ class TransformerBlock(nn.Module):
         context_freqs_cis: Tensor | None = None,
         cross_attention_mask: Tensor | None = None,
         skip_in_x: Tensor | None = None,
+        unpad_data: tuple[Tensor, Tensor] | None = None,
     ) -> Tensor:
         c = None if self.time_as_token else c
         if self.uvit_skip_connection and skip_in_x is not None:
             x = self.skip_in_linear(torch.cat([x, skip_in_x], dim=-1))
-        h = x + self.attention(self.attention_norm(x, c), freqs_cis, mask, input_pos)
+        h = x + self.attention(
+            self.attention_norm(x, c),
+            freqs_cis,
+            mask,
+            input_pos,
+            unpad_data=unpad_data,
+        )
         out = h + self.feed_forward(self.ffn_norm(h, c))
         return out
 
@@ -218,6 +237,7 @@ class Attention(nn.Module):
         input_pos: Tensor | None = None,
         context: Tensor | None = None,
         context_freqs_cis: Tensor | None = None,
+        unpad_data: tuple[Tensor, Tensor] | None = None,
     ) -> Tensor:
         bsz, seqlen, _ = x.shape
 
@@ -252,7 +272,37 @@ class Attention(nn.Module):
         # building AttentionMetadata entirely — this avoids the backend's
         # `torch.any(~mask)` D2H sync per ODE step and keeps the forward
         # CUDA-graph capturable.
-        if getattr(self, "_assume_full_mask", False):
+        full_mask_state = getattr(self, "_assume_full_mask", None)
+        packed_varlen = (
+            unpad_data is not None
+            and context is None
+            and q.device.type == "cuda"
+            and q.dtype != torch.float32
+            and hasattr(getattr(self.diff_attn, "attention", None), "_forward_varlen_packed")
+        )
+        if packed_varlen:
+            indices, cu_seqlens = unpad_data
+            packed_q = q.flatten(0, 1).index_select(0, indices).unsqueeze(0)
+            packed_k = k.flatten(0, 1).index_select(0, indices).unsqueeze(0)
+            packed_v = v.flatten(0, 1).index_select(0, indices).unsqueeze(0)
+            packed_metadata = AttentionMetadata(
+                extra={
+                    "cu_seqlens_q": cu_seqlens,
+                    "cu_seqlens_k": cu_seqlens,
+                    "max_seqlen_q": seqlen,
+                    "max_seqlen_k": seqlen,
+                }
+            )
+            packed_y = self.diff_attn(
+                packed_q,
+                packed_k,
+                packed_v,
+                attn_metadata=packed_metadata,
+            )
+            flat_y = torch.zeros_like(q.flatten(0, 1))
+            flat_y.index_copy_(0, indices, packed_y.squeeze(0))
+            y = flat_y.view_as(q)
+        elif full_mask_state is True:
             attn_metadata = None
         else:
             attn_mask = mask
@@ -260,8 +310,15 @@ class Attention(nn.Module):
                 # (B, 1, T, T) → (B, T) — take the first query row;
                 # all query positions share the same padding pattern.
                 attn_mask = attn_mask[:, 0, 0, :]
-            attn_metadata = AttentionMetadata(attn_mask=attn_mask) if attn_mask is not None else None
-        y = self.diff_attn(q, k, v, attn_metadata=attn_metadata)
+            attn_metadata = (
+                AttentionMetadata(
+                    attn_mask=attn_mask,
+                )
+                if attn_mask is not None
+                else None
+            )
+        if not packed_varlen:
+            y = self.diff_attn(q, k, v, attn_metadata=attn_metadata)
         y = y.flatten(2, 3)
 
         y = self.wo(y)
diff --git a/vllm_omni/model_executor/models/indextts2/s2mel/modules/wavenet.py b/vllm_omni/model_executor/models/indextts2/s2mel/modules/wavenet.py
index 4c5381766..f7910055e 100644
--- a/vllm_omni/model_executor/models/indextts2/s2mel/modules/wavenet.py
+++ b/vllm_omni/model_executor/models/indextts2/s2mel/modules/wavenet.py
@@ -3,6 +3,7 @@
 
 import torch
 from torch import nn
+from torch.nn import functional as F
 
 from vllm_omni.model_executor.models.indextts2.s2mel.modules.encodec import SConv1d
 
@@ -53,14 +54,82 @@ class WN(torch.nn.Module):
             res_skip_layer = conv1d_type(hidden_channels, res_skip_channels, 1, norm="weight_norm", causal=causal)
             self.res_skip_layers.append(res_skip_layer)
 
+        # The vectorized ragged path rebuilds logical right-reflect values in
+        # place and therefore requires each row to be strictly longer than the
+        # widest right padding. The decoder keeps shorter rows on the original
+        # exact-length singleton path, preserving SConv1d's existing behavior.
+        self.ragged_min_length = 1 + max(
+            ((layer.conv.conv.kernel_size[0] - 1) * layer.conv.conv.dilation[0] + 1 - layer.conv.conv.stride[0]) // 2
+            for layer in self.in_layers
+        )
+
+    @staticmethod
+    def _logical_reflect_in_layer(
+        in_layer: SConv1d,
+        x: torch.Tensor,
+        logical_lengths: torch.Tensor,
+    ) -> torch.Tensor:
+        """Run a WaveNet input convolution at each row's logical boundary.
+
+        ``SConv1d`` reflects at the physical tensor boundary. In a padded
+        request batch, shorter rows end before that boundary, so their right
+        reflection values must be rebuilt before the convolution. This path is
+        intentionally WaveNet-specific: its input layers are non-causal,
+        reflect-padded, stride-one convolutions. The decoder keeps rows that
+        are not strictly longer than the right reflection width on the
+        original singleton path.
+        """
+        conv = in_layer.conv.conv
+        stride = conv.stride[0]
+        dilation = conv.dilation[0]
+        effective_kernel = (conv.kernel_size[0] - 1) * dilation + 1
+        if in_layer.causal or in_layer.pad_mode != "reflect" or stride != 1:
+            raise RuntimeError(
+                "Ragged WaveNet batching requires non-causal reflect-padded stride-one input convolutions"
+            )
+
+        padding_total = effective_kernel - stride
+        padding_right = padding_total // 2
+        padding_left = padding_total - padding_right
+        padded = F.pad(x, (padding_left, padding_right), mode="reflect")
+
+        if padding_right:
+            offsets = torch.arange(
+                padding_right,
+                device=x.device,
+                dtype=torch.long,
+            ).unsqueeze(0)
+            lengths = logical_lengths.to(device=x.device, dtype=torch.long).reshape(-1, 1)
+            source_positions = padding_left + lengths - 2 - offsets
+            target_positions = padding_left + lengths + offsets
+            source_indices = source_positions.unsqueeze(1).expand(-1, x.shape[1], -1)
+            target_indices = target_positions.unsqueeze(1).expand(-1, x.shape[1], -1)
+            reflected = torch.gather(padded, dim=2, index=source_indices)
+            padded.scatter_(dim=2, index=target_indices, src=reflected)
+
+        return in_layer.conv(padded)
+
     def forward(self, x, x_mask, g=None, **kwargs):
         output = torch.zeros_like(x)
 
+        logical_lengths = None
+        if getattr(self, "_assume_full_mask", None) is False:
+            # Under CFG, x_mask has already been repeated from B to 2B in the
+            # same [conditional rows, unconditional rows] order as x.
+            logical_lengths = x_mask[:, 0, :].sum(dim=-1)
+
         if g is not None:
             g = self.cond_layer(g)
 
         for i in range(self.n_layers):
-            x_in = self.in_layers[i](x)
+            if logical_lengths is None:
+                x_in = self.in_layers[i](x)
+            else:
+                x_in = self._logical_reflect_in_layer(
+                    self.in_layers[i],
+                    x,
+                    logical_lengths,
+                )
             if g is not None:
                 cond_offset = i * 2 * self.hidden_channels
                 g_l = g[:, cond_offset : cond_offset + 2 * self.hidden_channels, :]
diff --git a/vllm_omni/model_executor/models/indextts2/text_processing_v2_5.py b/vllm_omni/model_executor/models/indextts2/text_processing_v2_5.py
new file mode 100644
index 000000000..8eae3045c
--- /dev/null
+++ b/vllm_omni/model_executor/models/indextts2/text_processing_v2_5.py
@@ -0,0 +1,328 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""Text preparation shared by IndexTTS 2.5 prompt sizing and model prefill."""
+
+from __future__ import annotations
+
+import re
+from collections.abc import Callable
+from functools import lru_cache
+
+from .tokenizer_v2_5 import (
+    INDEXTTS25_TOKENIZER_FILE,
+    encode_indextts25_text,
+    lang_to_token,
+    normalize_language_code,
+)
+
+PRONUNCIATION_ANNOTATION_PATTERN = re.compile(r"<([^|>\n]+)\|([^>\n]+)>")
+_SPECIAL_TOKEN_PATTERN = re.compile(r"<\|([^|]+)\|>")
+_PINYIN_TONE_PATTERN = re.compile(
+    r"(?<![a-z])"
+    r"((?:[bpmfdtnlgkhjqxzcsryw]|[zcs]h)?"
+    r"(?:[aeiouüv]|[ae]i|u[aio]|ao|ou|i[aue]|[uüv]e|[uvü]ang?|"
+    r"uai|[aeiuv]n|[aeio]ng|ia[no]|i[ao]ng)|ng|er)([1-5])",
+    re.IGNORECASE,
+)
+_NAME_PATTERN = re.compile(r"[\u4e00-\u9fff]+(?:[-·—][\u4e00-\u9fff]+){1,2}")
+_TECH_TERM_PATTERN = re.compile(r"[A-Za-z][A-Za-z0-9]*(?:-[A-Za-z0-9]+)+")
+_ENGLISH_CONTRACTION_PATTERN = re.compile(
+    r"(what|where|who|which|how|t?here|it|s?he|that|this)'s",
+    re.IGNORECASE,
+)
+_EMAIL_PATTERN = re.compile(r"^[a-zA-Z0-9]+@[a-zA-Z0-9]+\.[a-zA-Z]+$")
+
+_CHAR_REPLACEMENTS = {
+    "：": ",",
+    "；": ",",
+    ";": ",",
+    "，": ",",
+    "。": ".",
+    "！": "!",
+    "？": "?",
+    "\n": " ",
+    "·": "-",
+    "、": ",",
+    "...": "…",
+    ",,,": "…",
+    "，，，": "…",
+    "……": "…",
+    "“": "'",
+    "”": "'",
+    '"': "'",
+    "‘": "'",
+    "’": "'",
+    "（": "'",
+    "）": "'",
+    "(": "'",
+    ")": "'",
+    "《": "'",
+    "》": "'",
+    "【": "'",
+    "】": "'",
+    "[": "'",
+    "]": "'",
+    "—": "-",
+    "～": "-",
+    "~": "-",
+    "「": "'",
+    "」": "'",
+    ":": ",",
+}
+# Deliberately prefer the longest replacement. This diverges from the
+# insertion-ordered upstream regex so ``，，，`` becomes one ellipsis, not ``,,,``.
+_CLEAN_PATTERN = re.compile("|".join(re.escape(key) for key in sorted(_CHAR_REPLACEMENTS, key=len, reverse=True)))
+
+
+def _is_kana(text: str) -> bool:
+    return bool(re.fullmatch(r"[\u3040-\u309f]+", text) or re.fullmatch(r"[\u30a0-\u30ff]+", text))
+
+
+def apply_pronunciation_annotations(text: str) -> str:
+    """Convert ``<word|pronunciation>`` to the official special-token form."""
+
+    def replace(match: re.Match[str]) -> str:
+        word = match.group(1)
+        pronunciation = match.group(2).upper()
+        if _is_kana(pronunciation):
+            return f" {pronunciation} "
+        token = "SPECIAL_TOKEN_2" if re.search(r"[\u4e00-\u9fff]", word) else "SPECIAL_TOKEN_1"
+        return f"<|{token}|>{pronunciation}<|{token}|>"
+
+    return PRONUNCIATION_ANNOTATION_PATTERN.sub(replace, text)
+
+
+def clean_indextts25_text(text: str) -> str:
+    return _CLEAN_PATTERN.sub(lambda match: _CHAR_REPLACEMENTS[match.group()], text)
+
+
+@lru_cache(maxsize=2)
+def _load_wetext_normalizer(lang: str):
+    import platform
+
+    if platform.system() == "Linux":
+        try:
+            if lang == "zh":
+                from tn.chinese.normalizer import Normalizer
+            else:
+                from tn.english.normalizer import Normalizer
+        except ModuleNotFoundError as exc:
+            if exc.name != "tn":
+                raise
+            raise RuntimeError(
+                f"IndexTTS 2.5 text normalization backend for {lang!r} is unavailable. "
+                "Install it with pip install 'vllm-omni[indextts2]'"
+            ) from exc
+        if lang == "zh":
+            return Normalizer(
+                remove_interjections=False,
+                remove_erhua=False,
+                overwrite_cache=False,
+            )
+        return Normalizer(overwrite_cache=False)
+
+    try:
+        from wetext import Normalizer
+    except ModuleNotFoundError as exc:
+        if exc.name != "wetext":
+            raise
+        raise RuntimeError(
+            f"IndexTTS 2.5 text normalization backend for {lang!r} is unavailable. "
+            "Install it with pip install 'vllm-omni[indextts2]'"
+        ) from exc
+    if lang == "zh":
+        return Normalizer(remove_erhua=False, lang="zh", operator="tn")
+    return Normalizer(lang="en", operator="tn")
+
+
+def _uses_chinese_normalizer(text: str) -> bool:
+    has_chinese = bool(re.search(r"[\u4e00-\u9fff]", text))
+    has_alpha = bool(re.search(r"[a-zA-Z]", text))
+    if has_chinese or not has_alpha or _EMAIL_PATTERN.fullmatch(text):
+        return True
+    return bool(_PINYIN_TONE_PATTERN.search(text))
+
+
+def _protect_values(
+    text: str,
+    values: list[str],
+    *,
+    prefix: str,
+) -> tuple[str, list[str]]:
+    unique_values = sorted(set(values), key=len, reverse=True)
+    for index, value in enumerate(unique_values):
+        marker = f"<{prefix}_{chr(ord('a') + index)}>"
+        text = text.replace(value, marker)
+    return text, unique_values
+
+
+def _restore_values(
+    text: str,
+    values: list[str],
+    *,
+    prefix: str,
+    transform: Callable[[str], str] | None = None,
+) -> str:
+    for index, value in enumerate(values):
+        marker = f"<{prefix}_{chr(ord('a') + index)}>"
+        text = text.replace(marker, transform(value) if transform else value)
+    return text
+
+
+def _correct_pinyin(pinyin: str) -> str:
+    if not pinyin or pinyin[0] not in "jqxJQX":
+        return pinyin.upper()
+    return re.sub(
+        r"([jqx])[uü](n|e|an)*(\d)",
+        r"\g<1>v\g<2>\g<3>",
+        pinyin,
+        flags=re.IGNORECASE,
+    ).upper()
+
+
+def _normalize_zh_or_en(text: str) -> str:
+    normalizer_lang = "zh" if _uses_chinese_normalizer(text) else "en"
+    text = _ENGLISH_CONTRACTION_PATTERN.sub(r"\1 is", text)
+
+    tech_terms = _TECH_TERM_PATTERN.findall(text)
+    for term in sorted(set(tech_terms), key=len, reverse=True):
+        text = text.replace(term, term.replace("-", "<H>"))
+
+    pinyin_values: list[str] = []
+    name_values: list[str] = []
+    if normalizer_lang == "zh":
+        pinyin_values = [match.group(0) for match in _PINYIN_TONE_PATTERN.finditer(text)]
+        text, pinyin_values = _protect_values(
+            text,
+            pinyin_values,
+            prefix="pinyin",
+        )
+        text, name_values = _protect_values(
+            text,
+            _NAME_PATTERN.findall(text),
+            prefix="n",
+        )
+
+    result = _load_wetext_normalizer(normalizer_lang).normalize(text)
+    result = _restore_values(result, name_values, prefix="n")
+    result = _restore_values(
+        result,
+        pinyin_values,
+        prefix="pinyin",
+        transform=_correct_pinyin,
+    )
+    if tech_terms:
+        result = re.sub(r"\s*<H>\s*", "-", result)
+    if normalizer_lang == "zh":
+        result = result.replace("$", ".")
+    return clean_indextts25_text(result)
+
+
+def _normalize_with_official_backend(text: str, lang: str) -> str:
+    if lang in {"zh", "en", "zhen"}:
+        return _normalize_zh_or_en(text)
+    if lang == "es":
+        # NeMo is optional in the upstream implementation and falls back to
+        # raw text when its grammar package is unavailable.
+        try:
+            from nemo_text_processing.text_normalization.normalize import (
+                Normalizer,
+            )
+
+            normalizer = Normalizer(input_case="cased", lang="es")
+            return normalizer.normalize(text, verbose=False)
+        except ModuleNotFoundError as exc:
+            if exc.name != "nemo_text_processing":
+                raise
+            return text
+    return text
+
+
+@lru_cache(maxsize=1)
+def _load_japanese_tagger():
+    try:
+        import fugashi
+        import unidic_lite
+    except ModuleNotFoundError as exc:
+        if exc.name not in {"fugashi", "unidic_lite"}:
+            raise
+        raise RuntimeError(
+            "IndexTTS 2.5 Japanese preprocessing requires fugashi and unidic-lite. "
+            "Install them with pip install 'vllm-omni[indextts2]'"
+        ) from exc
+    _ = unidic_lite
+    return fugashi.Tagger()
+
+
+def _process_japanese_text(text: str) -> str:
+    """Tokenize Japanese like the official g2p_ratio=0 frontend."""
+
+    def process_segment(segment: str) -> str:
+        return " ".join(token.surface for token in _load_japanese_tagger()(segment))
+
+    parts = re.split(r"( +)", text)
+    return "".join(process_segment(part) if part.strip() else part for part in parts)
+
+
+def normalize_indextts25_text(
+    text: str,
+    *,
+    lang: str,
+    text_normalization: bool = True,
+    normalizer: Callable[[str, str], str] | None = None,
+) -> str:
+    """Apply the deterministic portion of the official preprocessing order.
+
+    A caller-provided normalizer is used for number/date expansion. Keeping it
+    injectable lets prompt sizing and Talker prefill use the same normalizer
+    instance and avoids constructing heavyweight TN grammars per request.
+    """
+    lang = normalize_language_code(lang)
+    text = clean_indextts25_text(text)
+    if text_normalization:
+        normalize = normalizer or _normalize_with_official_backend
+        text = normalize(text, lang)
+    if lang in {"ja", "zh", "en", "zhen"}:
+        text = text.lower()
+    elif lang == "es":
+        text = text.upper()
+    text = apply_pronunciation_annotations(text)
+    if lang == "ja":
+        text = _process_japanese_text(text)
+    return _SPECIAL_TOKEN_PATTERN.sub(
+        lambda match: f"<|{match.group(1).upper()}|>",
+        text,
+    )
+
+
+def prepare_indextts25_text(
+    text: str,
+    *,
+    lang: str,
+    model_dir: str,
+    tokenizer_file: str = INDEXTTS25_TOKENIZER_FILE,
+    text_normalization: bool = True,
+    normalizer: Callable[[str, str], str] | None = None,
+) -> tuple[list[int], int]:
+    if not text or not text.strip():
+        raise ValueError("IndexTTS 2.5 text cannot be empty")
+    lang_code = normalize_language_code(lang)
+    # When no heavyweight TN callback is installed, punctuation/casing and
+    # annotations are still deterministic. The Talker installs the official
+    # language-specific normalizer before enabling text_normalization.
+    normalized = normalize_indextts25_text(
+        text,
+        lang=lang_code,
+        text_normalization=text_normalization,
+        normalizer=normalizer,
+    )
+    # ``zhen`` is not a registered special token. Keep its official literal
+    # prefix so tiktoken encodes it through existing mergeable ranks; remapping
+    # it to ``common`` would change both the text ABI and preprocessing route.
+    prefixed = f"<|{lang_code}|> {normalized}"
+    token_ids = encode_indextts25_text(
+        prefixed,
+        model_dir=model_dir,
+        tokenizer_file=tokenizer_file,
+    )
+    return token_ids, lang_to_token(lang_code)
diff --git a/vllm_omni/model_executor/models/indextts2/tokenizer_v2_5.py b/vllm_omni/model_executor/models/indextts2/tokenizer_v2_5.py
new file mode 100644
index 000000000..6eae97703
--- /dev/null
+++ b/vllm_omni/model_executor/models/indextts2/tokenizer_v2_5.py
@@ -0,0 +1,286 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""IndexTTS 2.5 multilingual tiktoken vocabulary.
+
+The vocabulary layout mirrors the official IndexTTS 2.5 tokenizer: 58,836
+mergeable ranks followed by 1,673 registered special tokens.
+"""
+
+from __future__ import annotations
+
+import base64
+from functools import lru_cache
+from pathlib import Path
+from typing import Any
+
+INDEXTTS25_TOKENIZER_FILE = "multilingual_zh_ja_yue_char_del.tiktoken"
+INDEXTTS25_MERGEABLE_RANKS = 58836
+INDEXTTS25_VOCAB_SIZE = 60509
+INDEXTTS25_NUM_SPECIAL_LANGUAGES = 99
+
+# Order is checkpoint ABI: lang_embedding rows were trained against these IDs.
+LANGUAGES = (
+    "en",
+    "zh",
+    "de",
+    "es",
+    "ru",
+    "ko",
+    "fr",
+    "ja",
+    "pt",
+    "tr",
+    "pl",
+    "ca",
+    "nl",
+    "ar",
+    "sv",
+    "it",
+    "id",
+    "hi",
+    "fi",
+    "vi",
+    "he",
+    "uk",
+    "el",
+    "ms",
+    "cs",
+    "ro",
+    "da",
+    "hu",
+    "ta",
+    "no",
+    "th",
+    "ur",
+    "hr",
+    "bg",
+    "lt",
+    "la",
+    "mi",
+    "ml",
+    "cy",
+    "sk",
+    "te",
+    "fa",
+    "lv",
+    "bn",
+    "sr",
+    "az",
+    "sl",
+    "kn",
+    "et",
+    "mk",
+    "br",
+    "eu",
+    "is",
+    "hy",
+    "ne",
+    "mn",
+    "bs",
+    "kk",
+    "sq",
+    "sw",
+    "gl",
+    "mr",
+    "pa",
+    "si",
+    "km",
+    "sn",
+    "yo",
+    "so",
+    "af",
+    "oc",
+    "ka",
+    "be",
+    "tg",
+    "sd",
+    "gu",
+    "am",
+    "yi",
+    "lo",
+    "uz",
+    "fo",
+    "ht",
+    "ps",
+    "tk",
+    "nn",
+    "mt",
+    "sa",
+    "lb",
+    "my",
+    "bo",
+    "tl",
+    "mg",
+    "as",
+    "tt",
+    "haw",
+    "ln",
+    "ha",
+    "ba",
+    "jw",
+    "su",
+    "yue",
+    "minnan",
+    "wuyu",
+    "dialect",
+    "zh/en",
+    "en/zh",
+    "common",
+)
+LANGUAGE_DICT = {lang: index for index, lang in enumerate(LANGUAGES)}
+
+# ``zhen`` is an official mixed Chinese/English frontend mode, but it has no
+# dedicated checkpoint language-embedding row or registered special token.
+_FRONTEND_LANGUAGE_TO_EMBEDDING = {"zhen": "common"}
+
+TO_LANGUAGE_CODE = {
+    "english": "en",
+    "chinese": "zh",
+    "german": "de",
+    "spanish": "es",
+    "russian": "ru",
+    "korean": "ko",
+    "french": "fr",
+    "japanese": "ja",
+    "portuguese": "pt",
+    "turkish": "tr",
+    "cantonese": "yue",
+    # Intentional vLLM-Omni convenience alias; upstream would route the name
+    # ``mandarin`` to the ``common`` language-embedding row.
+    "mandarin": "zh",
+    "burmese": "my",
+    "valencian": "ca",
+    "flemish": "nl",
+    "haitian": "ht",
+    "letzeburgesch": "lb",
+    "pushto": "ps",
+    "panjabi": "pa",
+    "moldavian": "ro",
+    "moldovan": "ro",
+    "sinhalese": "si",
+    "castilian": "es",
+}
+
+_AUDIO_EVENTS = (
+    "ASR",
+    "AED",
+    "SER",
+    "Speech",
+    "/Speech",
+    "BGM",
+    "/BGM",
+    "Laughter",
+    "/Laughter",
+    "Applause",
+    "/Applause",
+)
+_EMOTIONS = ("HAPPY", "SAD", "ANGRY", "NEUTRAL")
+_TTS_VOCAL_TOKENS = (
+    "TTS/B",
+    "TTS/O",
+    "TTS/Q",
+    "TTS/A",
+    "TTS/CO",
+    "TTS/CL",
+    "TTS/H",
+    *(f"TTS/SP{i:02d}" for i in range(1, 14)),
+)
+
+INDEXTTS25_SPECIAL_TOKENS = (
+    "<|endoftext|>",
+    "<|startoftranscript|>",
+    *(f"<|{lang}|>" for lang in LANGUAGES[:INDEXTTS25_NUM_SPECIAL_LANGUAGES]),
+    *(f"<|{event}|>" for event in _AUDIO_EVENTS),
+    *(f"<|{emotion}|>" for emotion in _EMOTIONS),
+    "<|translate|>",
+    "<|transcribe|>",
+    "<|startoflm|>",
+    "<|startofprev|>",
+    "<|nospeech|>",
+    "<|notimestamps|>",
+    *(f"<|SPECIAL_TOKEN_{i}|>" for i in range(1, 31)),
+    *(f"<|{token}|>" for token in _TTS_VOCAL_TOKENS),
+    *(f"<|{i * 0.02:.2f}|>" for i in range(1501)),
+)
+
+_PATTERN = r"""'s|'t|'re|'ve|'m|'ll|'d| ?\p{L}+| ?\p{N}+| ?[^\s\p{L}\p{N}]+|\s+(?!\S)|\s+"""
+
+
+def normalize_language_code(lang: str) -> str:
+    normalized = lang.strip().lower()
+    normalized = TO_LANGUAGE_CODE.get(normalized, normalized)
+    if normalized not in LANGUAGE_DICT and normalized not in _FRONTEND_LANGUAGE_TO_EMBEDDING:
+        supported = (*LANGUAGES, *sorted(_FRONTEND_LANGUAGE_TO_EMBEDDING))
+        raise ValueError(f"Unsupported IndexTTS 2.5 language {lang!r}; expected one of {', '.join(supported)}")
+    return normalized
+
+
+def lang_to_token(lang: str) -> int:
+    normalized = normalize_language_code(lang)
+    embedding_language = _FRONTEND_LANGUAGE_TO_EMBEDDING.get(normalized, normalized)
+    return LANGUAGE_DICT[embedding_language]
+
+
+def resolve_indextts25_tokenizer_file(
+    model_dir: str,
+    tokenizer_file: str = INDEXTTS25_TOKENIZER_FILE,
+) -> str:
+    model_path = Path(model_dir).expanduser()
+    for root in (model_path, model_path / "checkpoints"):
+        direct = root / tokenizer_file
+        if direct.is_file():
+            return str(direct)
+    if model_path.is_file() and model_path.name == tokenizer_file:
+        return str(model_path)
+
+    try:
+        from huggingface_hub import hf_hub_download
+
+        return hf_hub_download(repo_id=model_dir, filename=tokenizer_file)
+    except Exception as exc:
+        raise FileNotFoundError(
+            f"Could not resolve IndexTTS 2.5 tokenizer {tokenizer_file!r} from {model_dir!r}"
+        ) from exc
+
+
+@lru_cache(maxsize=16)
+def load_indextts25_encoding(
+    model_dir: str,
+    tokenizer_file: str = INDEXTTS25_TOKENIZER_FILE,
+) -> Any:
+    import tiktoken
+
+    vocab_path = resolve_indextts25_tokenizer_file(model_dir, tokenizer_file)
+    with open(vocab_path, encoding="utf-8") as vocab:
+        ranks = {
+            base64.b64decode(token): int(rank) for line in vocab if line.strip() for token, rank in (line.split(),)
+        }
+
+    if len(ranks) != INDEXTTS25_MERGEABLE_RANKS:
+        raise ValueError(
+            f"IndexTTS 2.5 tokenizer {vocab_path!r} has {len(ranks)} "
+            f"mergeable ranks; expected {INDEXTTS25_MERGEABLE_RANKS}"
+        )
+    special_tokens = {token: len(ranks) + index for index, token in enumerate(INDEXTTS25_SPECIAL_TOKENS)}
+    explicit_n_vocab = len(ranks) + len(special_tokens)
+    if explicit_n_vocab != INDEXTTS25_VOCAB_SIZE:
+        raise ValueError(
+            f"IndexTTS 2.5 tokenizer builds vocab size {explicit_n_vocab}; expected {INDEXTTS25_VOCAB_SIZE}"
+        )
+    return tiktoken.Encoding(
+        name=Path(vocab_path).name,
+        explicit_n_vocab=explicit_n_vocab,
+        pat_str=_PATTERN,
+        mergeable_ranks=ranks,
+        special_tokens=special_tokens,
+    )
+
+
+def encode_indextts25_text(
+    text: str,
+    *,
+    model_dir: str,
+    tokenizer_file: str = INDEXTTS25_TOKENIZER_FILE,
+) -> list[int]:
+    encoding = load_indextts25_encoding(model_dir, tokenizer_file)
+    return encoding.encode(text, allowed_special="all")
diff --git a/vllm_omni/model_executor/models/registry.py b/vllm_omni/model_executor/models/registry.py
index fd76dadd8..3c79ba34c 100644
--- a/vllm_omni/model_executor/models/registry.py
+++ b/vllm_omni/model_executor/models/registry.py
@@ -369,6 +369,17 @@ _OMNI_MODELS = {
         "indextts2_s2mel_decoder",
         "IndexTTS2S2MelDecoder",
     ),
+    ## IndexTTS 2.5 (shared implementations, versioned HF config)
+    "IndexTTS25TalkerForConditionalGeneration": (
+        "indextts2",
+        "indextts2_talker",
+        "IndexTTS2TalkerForConditionalGeneration",
+    ),
+    "IndexTTS25S2MelDecoder": (
+        "indextts2",
+        "indextts2_s2mel_decoder",
+        "IndexTTS2S2MelDecoder",
+    ),
     ## Ming-flash-omni-2.0
     "MingFlashOmniForConditionalGeneration": (
         "ming_flash_omni",
diff --git a/vllm_omni/model_executor/stage_input_processors/indextts2.py b/vllm_omni/model_executor/stage_input_processors/indextts2.py
index 39d9d011c..3cf4e74c5 100644
--- a/vllm_omni/model_executor/stage_input_processors/indextts2.py
+++ b/vllm_omni/model_executor/stage_input_processors/indextts2.py
@@ -26,21 +26,21 @@ def _cpu_view(tensor: torch.Tensor) -> torch.Tensor:
 
 def _strip_stop_token(
     codes: torch.Tensor,
-    latent: torch.Tensor,
+    latent: torch.Tensor | None,
     stop_mel_token: int = STOP_MEL_TOKEN,
-) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
+) -> tuple[torch.Tensor, torch.Tensor | None, torch.Tensor]:
     """Strip at the first stop token, matching official IndexTTS2 v2.
 
-    Returns: (codes [B, T'], latent [B, T', D], code_lens [B]).
+    Returns codes, optional aligned latent, and code lengths.
     """
     if codes.ndim == 1:
         codes = codes.unsqueeze(0)
-    if latent.ndim == 2:
+    if latent is not None and latent.ndim == 2:
         latent = latent.unsqueeze(0)
 
     if codes.device.type != "cpu":
         codes = codes.detach().cpu()
-    if latent.device.type != "cpu":
+    if latent is not None and latent.device.type != "cpu":
         latent = latent.detach().cpu()
 
     device = codes.device
@@ -50,8 +50,6 @@ def _strip_stop_token(
 
     for i in range(codes.shape[0]):
         code = codes[i]
-        lat = latent[i]
-
         stop_mask = (code == stop_mel_token).nonzero(as_tuple=False)
         if stop_mask.numel() > 0:
             valid_len = int(stop_mask[0].item())
@@ -59,27 +57,50 @@ def _strip_stop_token(
             valid_len = int(code.shape[0])
         code_lens.append(valid_len)
         codes_out.append(code[:valid_len])
-        latent_out.append(lat[:valid_len])
+        if latent is not None:
+            latent_out.append(latent[i, :valid_len])
 
     max_len = max(code_lens) if code_lens else 0
     if max_len == 0:
+        empty_codes = torch.zeros(codes.shape[0], 0, dtype=torch.long, device=device)
+        empty_latent = (
+            torch.zeros(
+                codes.shape[0],
+                0,
+                latent.shape[-1],
+                device=device,
+                dtype=latent.dtype,
+            )
+            if latent is not None
+            else None
+        )
         return (
-            torch.zeros(codes.shape[0], 0, dtype=torch.long, device=device),
-            torch.zeros(codes.shape[0], 0, latent.shape[-1], device=device, dtype=latent.dtype),
-            torch.zeros(codes.shape[0], dtype=torch.long, device=device),
+            empty_codes,
+            empty_latent,
+            torch.zeros(
+                codes.shape[0],
+                dtype=torch.long,
+                device=device,
+            ),
         )
 
     padded_codes = torch.zeros((len(codes_out), max_len), dtype=torch.long, device=device)
-    padded_latent = torch.zeros(
-        len(latent_out),
-        max_len,
-        latent_out[0].shape[-1],
-        device=device,
-        dtype=latent_out[0].dtype,
+    padded_latent = (
+        torch.zeros(
+            len(latent_out),
+            max_len,
+            latent_out[0].shape[-1],
+            device=device,
+            dtype=latent_out[0].dtype,
+        )
+        if latent_out
+        else None
     )
-    for i, (c, lat) in enumerate(zip(codes_out, latent_out)):
+    for i, c in enumerate(codes_out):
         padded_codes[i, : c.shape[0]] = c
-        padded_latent[i, : lat.shape[0]] = lat
+        if padded_latent is not None:
+            lat = latent_out[i]
+            padded_latent[i, : lat.shape[0]] = lat
 
     return padded_codes, padded_latent, torch.tensor(code_lens, dtype=torch.long, device=device)
 
@@ -105,26 +126,33 @@ def _normalize_latent_sequence(latent: torch.Tensor) -> torch.Tensor:
 
 def _build_s2mel_additional_information(
     mel_codes: torch.Tensor,
-    latent: torch.Tensor,
+    latent: torch.Tensor | None,
     meta: dict[str, Any],
     *,
+    use_gpt_latent: bool,
     context: str,
 ) -> dict[str, Any]:
     """Build the Stage-1 S2Mel tensor contract shared by legacy and connector paths."""
     mel_codes_clean, latent_clean, code_lens = _strip_stop_token(mel_codes, latent)
 
     additional_information = {
-        "latent": _cpu_view(latent_clean),
         "mel_codes": _cpu_view(mel_codes_clean),
         "code_lens": _cpu_view(code_lens),
+        "use_gpt_latent": use_gpt_latent,
     }
+    if use_gpt_latent:
+        if latent_clean is None:
+            raise ValueError(f"{context} requires GPT latent but none was provided")
+        additional_information["latent"] = _cpu_view(latent_clean)
+
+    duration_factor = meta.get("duration_factor", 1.0)
+    additional_information["duration_factor"] = 1.0 if duration_factor is None else float(duration_factor)
 
     for key in ("S_ref", "ref_mel", "style"):
         val = meta.get(key)
-        if isinstance(val, torch.Tensor):
-            additional_information[key] = _cpu_view(val)
-        else:
-            logger.warning("[%s] %s MISSING — Stage 1 will use fallback", context, key)
+        if not isinstance(val, torch.Tensor) or val.numel() == 0:
+            raise ValueError(f"{context} requires non-empty IndexTTS conditioning field {key}")
+        additional_information[key] = _cpu_view(val)
 
     return additional_information
 
@@ -143,6 +171,12 @@ def _request_id(request: Any) -> str:
     return str(getattr(request, "external_req_id", None) or getattr(request, "request_id", "?"))
 
 
+def _request_seed(request: Any) -> int | None:
+    sampling_params = getattr(request, "sampling_params", None)
+    seed = getattr(sampling_params, "seed", None)
+    return int(seed) if seed is not None else None
+
+
 def talker2s2mel_token_only(
     source_outputs: list[Any],
     prompt: Any = None,
@@ -177,36 +211,78 @@ def talker2s2mel_full_payload(
     del transfer_manager
     rid = _request_id(request)
     if not isinstance(pooling_output, dict):
-        logger.warning("talker2s2mel_full_payload: pooling_output not a dict for req=%s", rid)
-        return None
+        raise ValueError(f"IndexTTS Stage 0 payload must be a dict for req={rid}")
+
+    use_gpt_latent_value = _get_payload_value(
+        pooling_output,
+        "meta.use_gpt_latent",
+        "meta",
+        "use_gpt_latent",
+    )
+    if use_gpt_latent_value is None:
+        raise ValueError(f"IndexTTS payload is missing meta.use_gpt_latent for req={rid}")
+    use_gpt_latent = bool(use_gpt_latent_value)
+    payload_latent = _get_payload_value(
+        pooling_output,
+        "hidden_states.latent",
+        "hidden_states",
+        "latent",
+    )
+    payload_mel_codes = _get_payload_value(
+        pooling_output,
+        "codes.mel",
+        "codes",
+        "mel",
+    )
+    if use_gpt_latent:
+        mel_codes = payload_mel_codes
+        latent = payload_latent
+    else:
+        output_token_ids = list(getattr(request, "output_token_ids", None) or [])
+        if not output_token_ids:
+            raise ValueError(f"IndexTTS code-only payload has no completed output_token_ids for req={rid}")
+        mel_codes = torch.tensor(output_token_ids, dtype=torch.long)
+        latent = None
 
-    mel_codes = _get_payload_value(pooling_output, "codes.mel", "codes", "mel")
     if not isinstance(mel_codes, torch.Tensor) or mel_codes.numel() == 0:
-        logger.warning("talker2s2mel_full_payload: missing codes.mel for req=%s", rid)
-        return None
-
-    latent = _get_payload_value(pooling_output, "hidden_states.latent", "hidden_states", "latent")
-    if not isinstance(latent, torch.Tensor) or latent.numel() == 0:
-        logger.warning("talker2s2mel_full_payload: missing hidden_states.latent for req=%s", rid)
-        return None
+        raise ValueError(f"IndexTTS payload is missing mel codes for req={rid} (use_gpt_latent={use_gpt_latent})")
 
     mel_seq = _normalize_mel_sequence(mel_codes)
-    latent_seq = _normalize_latent_sequence(latent)
-    if mel_seq.numel() == 0 or latent_seq.numel() == 0:
-        logger.warning("talker2s2mel_full_payload: empty normalized mel/latent for req=%s", rid)
-        return None
+    if mel_seq.numel() == 0:
+        raise ValueError(f"IndexTTS payload has an empty mel sequence for req={rid}")
 
-    common_len = min(int(mel_seq.shape[0]), int(latent_seq.shape[0]))
-    if common_len <= 0:
-        logger.warning("talker2s2mel_full_payload: no common mel/latent length for req=%s", rid)
-        return None
-
-    mel_seq = mel_seq[:common_len]
-    latent_seq = latent_seq[:common_len]
+    latent_seq: torch.Tensor | None = None
+    if use_gpt_latent:
+        if not isinstance(latent, torch.Tensor) or latent.numel() == 0:
+            raise ValueError(f"IndexTTS latent payload is missing hidden_states.latent for req={rid}")
+        latent_seq = _normalize_latent_sequence(latent)
+        if latent_seq.numel() == 0:
+            raise ValueError(f"IndexTTS payload has an empty latent sequence for req={rid}")
+        if mel_seq.shape[0] != latent_seq.shape[0]:
+            raise ValueError(
+                f"IndexTTS mel/latent length mismatch for req={rid}: "
+                f"mel={mel_seq.shape[0]} latent={latent_seq.shape[0]}"
+            )
 
     meta = {
         "S_ref": _get_payload_value(pooling_output, "meta.S_ref", "meta", "S_ref"),
         "ref_mel": _get_payload_value(pooling_output, "meta.ref_mel", "meta", "ref_mel"),
         "style": _get_payload_value(pooling_output, "meta.style", "meta", "style"),
+        "duration_factor": _get_payload_value(
+            pooling_output,
+            "meta.duration_factor",
+            "meta",
+            "duration_factor",
+        ),
     }
-    return _build_s2mel_additional_information(mel_seq, latent_seq, meta, context="full_payload")
+    additional_information = _build_s2mel_additional_information(
+        mel_seq,
+        latent_seq,
+        meta,
+        use_gpt_latent=use_gpt_latent,
+        context="full_payload",
+    )
+    seed = _request_seed(request)
+    if seed is not None:
+        additional_information["seed"] = seed
+    return additional_information
diff --git a/vllm_omni/request.py b/vllm_omni/request.py
index 2f1fd5379..0606bcfc8 100644
--- a/vllm_omni/request.py
+++ b/vllm_omni/request.py
@@ -41,6 +41,10 @@ class OmniRequest(Request):
         if prompt_embeds is not None:
             kwargs["prompt_embeds"] = self._maybe_decode_prompt_embeds(prompt_embeds)
         super().__init__(*args, **kwargs)
+        # vLLM 0.27 owns this counter; accelerator images still based on 0.26
+        # do not. Keep the Omni scheduler's stale-output drain compatible with
+        # both request layouts until those images move to 0.27.
+        self.num_stale_output_tokens = int(getattr(self, "num_stale_output_tokens", 0) or 0)
         # Preserve serialized prompt embeddings payload (optional)
         self.prompt_embeds_payload: PromptEmbedsPayload | None = (
             prompt_embeds if isinstance(prompt_embeds, PromptEmbedsPayload) else None
diff --git a/vllm_omni/utils/mm_outputs.py b/vllm_omni/utils/mm_outputs.py
index af8f9ac14..1a380932b 100644
--- a/vllm_omni/utils/mm_outputs.py
+++ b/vllm_omni/utils/mm_outputs.py
@@ -106,6 +106,60 @@ def build_mm_cpu(multimodal_outputs: dict) -> dict[str, object]:
     return mm_cpu
 
 
+def snapshot_mm_payload(multimodal_outputs: dict) -> dict[str, object]:
+    """Snapshot a multimodal payload without moving it off its device.
+
+    Request-end full-payload producers retain these tensors across decode
+    steps. CUDA graph outputs and runner input buffers may be reused on the
+    next step, so retaining views is not sufficient: CUDA tensors must be
+    copied first. Compatible per-request tensor lists are packed with one
+    ``torch.cat`` and restored as views, avoiding one tiny copy kernel per
+    active request.
+    """
+    if not multimodal_outputs:
+        return {}
+    return {key: _snapshot_payload_value(value) for key, value in multimodal_outputs.items()}
+
+
+def _snapshot_payload_value(value):
+    if isinstance(value, torch.Tensor):
+        tensor = value.detach()
+        return tensor.clone() if tensor.device.type != "cpu" else tensor
+    if isinstance(value, dict):
+        return {key: _snapshot_payload_value(item) for key, item in value.items()}
+    if isinstance(value, list):
+        if not value:
+            return value
+        first = value[0]
+        if (
+            len(value) > 1
+            and isinstance(first, torch.Tensor)
+            and first.ndim > 0
+            and first.layout == torch.strided
+            and all(
+                isinstance(item, torch.Tensor)
+                and item.ndim == first.ndim
+                and item.layout == first.layout
+                and item.device == first.device
+                and item.dtype == first.dtype
+                and tuple(item.shape[1:]) == tuple(first.shape[1:])
+                for item in value
+            )
+        ):
+            packed = torch.cat([item.detach() for item in value], dim=0)
+            output = []
+            offset = 0
+            for item in value:
+                length = item.shape[0]
+                output.append(packed.narrow(0, offset, length))
+                offset += length
+            return output
+        return [_snapshot_payload_value(item) for item in value]
+    if isinstance(value, tuple):
+        return tuple(_snapshot_payload_value(item) for item in value)
+    return value
+
+
 def _to_cpu(value):
     """Recursively detach + move tensors to CPU; preserve dict/list nesting."""
     if isinstance(value, torch.Tensor):
diff --git a/vllm_omni/worker/gpu_ar_model_runner.py b/vllm_omni/worker/gpu_ar_model_runner.py
index cb6e57579..b68c722ec 100644
--- a/vllm_omni/worker/gpu_ar_model_runner.py
+++ b/vllm_omni/worker/gpu_ar_model_runner.py
@@ -46,7 +46,12 @@ from vllm_omni.distributed.omni_connectors.utils.config import (
     stage_sends_async_output,
 )
 from vllm_omni.outputs import OmniModelRunnerOutput
-from vllm_omni.utils.mm_outputs import build_mm_cpu, partition_payload_list, to_payload_element
+from vllm_omni.utils.mm_outputs import (
+    build_mm_cpu,
+    partition_payload_list,
+    snapshot_mm_payload,
+    to_payload_element,
+)
 from vllm_omni.worker.gpu_model_runner import OmniGPUModelRunner
 from vllm_omni.worker.omni_connector_model_runner_mixin import OmniConnectorModelRunnerMixin
 from vllm_omni.worker.runner_assisted_metadata import RunnerAssistedFullAttentionMetadataRequest
@@ -1715,6 +1720,35 @@ class GPUARModelRunner(OmniGPUModelRunner, OmniConnectorModelRunnerMixin):
     def _model_omni_pooler_payload_include_hidden(self) -> bool:
         return self._runner_model_omni_flag("omni_pooler_payload_include_hidden", default=True)
 
+    def _should_defer_full_payload_d2h(self) -> bool:
+        """Keep opted-in full payloads on device until request completion."""
+        return (
+            getattr(self, "omni_prefix_cache", None) is None
+            and self._runner_model_omni_flag("omni_payload_at_request_end")
+            and self._should_accumulate_full_payload_output()
+        )
+
+    def _build_omni_step_outputs(
+        self,
+        pooler_inter: list[dict[str, object]],
+        pooler_client: list[dict[str, object]],
+        *,
+        defer_full_payload_d2h: bool,
+    ) -> tuple[
+        list[dict[str, torch.Tensor] | None] | None,
+        list[dict[str, torch.Tensor] | None] | None,
+    ]:
+        if defer_full_payload_d2h:
+            # The connector-side full-payload accumulator owns the snapshots.
+            # Nothing from an intermediate stage needs to cross the worker/core
+            # boundary on each decode step.
+            return None, None
+        inter_stage_outputs = self._build_multimodal_outputs(pooler_inter)
+        multimodal_outputs = (
+            inter_stage_outputs if pooler_client is pooler_inter else self._build_multimodal_outputs(pooler_client)
+        )
+        return inter_stage_outputs, multimodal_outputs
+
     def _should_use_async_omni_output(self) -> bool:
         if not self.use_async_scheduling:
             return False
@@ -1879,6 +1913,7 @@ class GPUARModelRunner(OmniGPUModelRunner, OmniConnectorModelRunnerMixin):
 
         needs_pooler_payload = len(downstream_req_ids) > 0
         downstream_req_id_set = set(downstream_req_ids)
+        defer_full_payload_d2h = needs_pooler_payload and self._should_defer_full_payload_d2h()
         hidden_states_cpu = None
         req_hidden_states_cpu: dict[str, torch.Tensor] | None = None
         include_hidden_payload = self._model_omni_pooler_payload_include_hidden()
@@ -1933,10 +1968,13 @@ class GPUARModelRunner(OmniGPUModelRunner, OmniConnectorModelRunnerMixin):
                     needs_scheduled_hidden_payload=needs_scheduled_hidden_payload,
                 )
             if combined_multimodal_outputs is None:
-                with record_function_or_nullcontext("omni_output_builder:build_mm_cpu"):
-                    mm_cpu = build_mm_cpu(
-                        flatten_payload(multimodal_outputs) if multimodal_outputs else multimodal_outputs
-                    )
+                flat_mm = flatten_payload(multimodal_outputs) if multimodal_outputs else multimodal_outputs
+                if defer_full_payload_d2h:
+                    with record_function_or_nullcontext("omni_output_builder:snapshot_mm_payload"):
+                        mm_cpu = snapshot_mm_payload(flat_mm)
+                else:
+                    with record_function_or_nullcontext("omni_output_builder:build_mm_cpu"):
+                        mm_cpu = build_mm_cpu(flat_mm)
 
             with record_function_or_nullcontext("omni_output_builder:process_additional_information"):
                 if not postprocess_already_applied:
@@ -1995,9 +2033,10 @@ class GPUARModelRunner(OmniGPUModelRunner, OmniConnectorModelRunnerMixin):
                         self.accumulate_full_payload_output(rid, pooler_inter[i], req_state)
 
         with record_function_or_nullcontext("omni_output_builder:build_multimodal_outputs"):
-            inter_stage_outputs = self._build_multimodal_outputs(pooler_inter)
-            multimodal_outputs = (
-                inter_stage_outputs if pooler_client is pooler_inter else self._build_multimodal_outputs(pooler_client)
+            inter_stage_outputs, multimodal_outputs = self._build_omni_step_outputs(
+                pooler_inter,
+                pooler_client,
+                defer_full_payload_d2h=defer_full_payload_d2h,
             )
 
         with record_function_or_nullcontext("gpu_model_runner: ModelRunnerOutput"):