diff --git a/docs/user_guide/examples/offline_inference/text_to_speech.md b/docs/user_guide/examples/offline_inference/text_to_speech.md
index a6544c1e5..95ffc5543 100644
--- a/docs/user_guide/examples/offline_inference/text_to_speech.md
+++ b/docs/user_guide/examples/offline_inference/text_to_speech.md
@@ -126,11 +126,7 @@ python examples/offline_inference/text_to_speech/cosyvoice3/end2end.py \
 ## Fish Speech S2 Pro
 
 4B dual-AR text-to-speech model from FishAudio with the DAC codec at 44.1 kHz.
-
-### Prerequisites
-```bash
-pip install fish-speech
-```
+No extra packages are required; the DAC codec is vendored in vLLM-Omni.
 
 ### Quick start
 ```bash
diff --git a/docs/user_guide/examples/online_serving/text_to_speech.md b/docs/user_guide/examples/online_serving/text_to_speech.md
index f1b643ac7..9a33dc858 100644
--- a/docs/user_guide/examples/online_serving/text_to_speech.md
+++ b/docs/user_guide/examples/online_serving/text_to_speech.md
@@ -155,13 +155,8 @@ The client supports `--api-base`, `--model`, `--text`, `--ref-audio`, `--ref-tex
 
 ## Fish Speech S2 Pro
 
-4B dual-AR TTS at 44.1 kHz. Server uses the DAC codec.
-
-### Prerequisites
-
-```bash
-pip install fish-speech
-```
+4B dual-AR TTS at 44.1 kHz. Server uses the DAC codec, which is vendored in
+vLLM-Omni (no extra packages required).
 
 ### Launch
 
diff --git a/examples/offline_inference/text_to_speech/README.md b/examples/offline_inference/text_to_speech/README.md
index c21bff5fe..da00ea44d 100644
--- a/examples/offline_inference/text_to_speech/README.md
+++ b/examples/offline_inference/text_to_speech/README.md
@@ -130,11 +130,7 @@ Text → [Stage 0: AR] → Speech Tokens → [Stage 1: DiT + HiFT] → Audio (24
 ## Fish Speech S2 Pro
 
 4B dual-AR text-to-speech model from FishAudio with the DAC codec at 44.1 kHz.
-
-### Prerequisites
-```bash
-pip install fish-speech
-```
+No extra packages are required; the DAC codec is vendored in vLLM-Omni.
 
 ### Quick start
 ```bash
diff --git a/examples/online_serving/text_to_speech/README.md b/examples/online_serving/text_to_speech/README.md
index e1cdd58dd..a4cf2fdb9 100644
--- a/examples/online_serving/text_to_speech/README.md
+++ b/examples/online_serving/text_to_speech/README.md
@@ -255,13 +255,8 @@ python examples/online_serving/text_to_speech/indextts2/speech_client.py \
 
 ## Fish Speech S2 Pro
 
-4B dual-AR TTS at 44.1 kHz. Server uses the DAC codec.
-
-### Prerequisites
-
-```bash
-pip install fish-speech
-```
+4B dual-AR TTS at 44.1 kHz. Server uses the DAC codec, which is vendored in
+vLLM-Omni (no extra packages required).
 
 ### Kvcache attention fast path
 
diff --git a/pyproject.toml b/pyproject.toml
index cd7544af8..ce1eb9a13 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -378,3 +378,7 @@ ba = "ba"
 SER = "SER"
 # NumPy ndarray.flags.writeable (canonical flag name, not "writable").
 writeable = "writeable"
+# "convnet" abbreviates convolutional network. It appears in the vendored Fish
+# Speech DAC codec identifiers (convnet_type, transconvnet_type) and is not a
+# typo of "convent".
+convnet = "convnet"
diff --git a/recipes/fishaudio/Fish-Speech-S2-Pro.md b/recipes/fishaudio/Fish-Speech-S2-Pro.md
index dca9f537e..167bedb04 100644
--- a/recipes/fishaudio/Fish-Speech-S2-Pro.md
+++ b/recipes/fishaudio/Fish-Speech-S2-Pro.md
@@ -36,19 +36,13 @@ Other hardware and configurations are welcome as community validation lands.
 
 - OS: Linux
 - Python: 3.10+
-- Required package: `fish-speech` (for DAC codec)
 - CUDA 12.8
 - vLLM version: 0.19.0
 - vLLM-Omni version or commit: c93359bb354a6aa5c14d062430cb85b2c4db251e
 
-```bash
-# Install PortAudio dependency if missing (required by pyaudio which is a dependency of fish-speech)
-# For Ubuntu/Debian:
-if ! dpkg -l | grep -q libportaudio2; then
-    sudo apt-get update && sudo apt-get install -y libportaudio2 portaudio19-dev
-fi
-pip install fish-speech
-```
+No extra packages are required: the DAC codec architecture is vendored in
+vLLM-Omni (`vllm_omni/model_executor/models/fish_speech/dac_modules/`), so the
+model runs out of the box, including in the official Docker image.
 
 #### Kvcache attention fast path
 
@@ -129,7 +123,6 @@ curl -X POST http://localhost:8091/v1/audio/speech \
 
 - OS: Linux
 - Python: 3.10+
-- Required package: `fish-speech` (for DAC codec)
 - CUDA 12.8
 - vLLM version: 0.19.0+
 
diff --git a/tests/model_executor/models/fish_speech/test_dac_modules.py b/tests/model_executor/models/fish_speech/test_dac_modules.py
new file mode 100644
index 000000000..0896f5533
--- /dev/null
+++ b/tests/model_executor/models/fish_speech/test_dac_modules.py
@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""CPU tests for the vendored DAC codec modules (dac_modules).
+
+Guards the checkpoint contract: the module tree built by build_dac_codec()
+must keep the exact parameter/buffer names and shapes that codec.pth was
+saved with (verified against the upstream fish-speech 0.1.0 package), and
+the encode/decode surfaces used by dac_encoder.py / fish_speech_dac_decoder.py
+must keep their shapes.
+"""
+
+import pytest
+import torch
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+# Spot checks covering every submodule family and both weight-norm styles.
+# Derived from the upstream fish-speech 0.1.0 state dict (541 entries total);
+# legacy weight_norm (weight_g/weight_v) comes from the descript quantizer
+# projections, parametrizations.weight.original0/1 from the causal convs.
+EXPECTED_KEY_SAMPLES = [
+    # encoder: first conv + deepest encoder-block transformer
+    "encoder.block.0.conv.parametrizations.weight.original0",
+    "encoder.block.4.block.5.layers.3.attention.wqkv.weight",
+    "encoder.block.4.block.5.freqs_cis",
+    "encoder.block.1.block.0.block.0.alpha",
+    # quantizer: semantic + residual VQ (legacy weight_norm keys)
+    "quantizer.semantic_quantizer.quantizers.0.codebook.weight",
+    "quantizer.quantizer.quantizers.8.in_proj.weight_g",
+    "quantizer.quantizer.quantizers.8.in_proj.weight_v",
+    # quantizer pre/post transformers + down/upsample convnext
+    "quantizer.pre_module.layers.7.feed_forward.w1.weight",
+    "quantizer.post_module.norm.weight",
+    "quantizer.downsample.1.1.dwconv.conv.weight",
+    "quantizer.upsample.0.0.conv.weight",
+    # decoder: transposed conv + final conv
+    "decoder.model.1.block.1.conv.parametrizations.weight.original1",
+    "decoder.model.6.conv.parametrizations.weight.original0",
+]
+
+NUM_STATE_DICT_ENTRIES = 541
+DAC_NUM_CODEBOOKS = 10  # 1 semantic + 9 residual
+
+
+@pytest.fixture(scope="module")
+def codec():
+    from vllm_omni.model_executor.models.fish_speech.dac_utils import build_dac_codec
+
+    model = build_dac_codec()
+    model.eval()
+    return model
+
+
+def test_state_dict_contract(codec):
+    sd = codec.state_dict()
+    assert len(sd) == NUM_STATE_DICT_ENTRIES
+    for key in EXPECTED_KEY_SAMPLES:
+        assert key in sd, f"checkpoint-contract key missing: {key}"
+
+
+def test_no_fish_speech_import_required(codec):
+    import sys
+
+    assert "fish_speech" not in sys.modules, "vendored codec must not import the fish-speech package"
+
+
+@torch.no_grad()
+def test_encode_shapes(codec):
+    frame_length = codec.frame_length  # 2048 samples per code frame
+    wav = torch.randn(1, 1, frame_length * 3 + 100)
+    lengths = torch.tensor([wav.shape[-1]], dtype=torch.long)
+    codes, code_lengths = codec.encode(wav, lengths)
+    assert codes.shape[0] == 1
+    assert codes.shape[1] == DAC_NUM_CODEBOOKS
+    assert codes.shape[2] == 4  # ceil(3.x frames)
+    assert code_lengths.tolist() == [4]
+    assert codes.dtype in (torch.int64, torch.int32)
+
+
+@torch.no_grad()
+def test_decode_shapes(codec):
+    frames = 8
+    codes = torch.randint(0, 1024, (1, DAC_NUM_CODEBOOKS, frames), dtype=torch.long)
+    feature_lengths = torch.tensor([frames], dtype=torch.long)
+    wav, audio_lengths = codec.decode(codes, feature_lengths)
+    assert wav.shape[0] == 1 and wav.shape[1] == 1
+    assert audio_lengths.tolist() == [frames * codec.frame_length]
+    assert wav.shape[-1] >= audio_lengths[0] - codec.frame_length
+
+
+@torch.no_grad()
+def test_decoder_runner_mutations(codec):
+    """The stage-1 runner prunes encode-only parts and bakes weight norm;
+    decode must still work afterwards (mirrors fish_speech_dac_decoder)."""
+    from torch.nn.utils.parametrize import remove_parametrizations
+
+    codec.encoder = None
+    codec.quantizer.pre_module = None
+    codec.quantizer.downsample = None
+    for module in codec.modules():
+        parametrizations = getattr(module, "parametrizations", None)
+        if not parametrizations:
+            continue
+        for name in list(parametrizations.keys()):
+            remove_parametrizations(module, name, leave_parametrized=True)
+
+    codes = torch.randint(0, 1024, (2, DAC_NUM_CODEBOOKS, 5), dtype=torch.long)
+    wav, audio_lengths = codec.decode(codes, torch.tensor([5, 3], dtype=torch.long))
+    assert wav.shape[0] == 2
+    assert audio_lengths.tolist() == [5 * codec.frame_length, 3 * codec.frame_length]
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_modules/__init__.py b/vllm_omni/model_executor/models/fish_speech/dac_modules/__init__.py
new file mode 100644
index 000000000..654916598
--- /dev/null
+++ b/vllm_omni/model_executor/models/fish_speech/dac_modules/__init__.py
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""Vendored DAC codec modules for Fish Speech S2 Pro.
+
+Adopted from the ``fish-speech`` 0.1.0 PyPI release
+(https://pypi.org/project/fish-speech/0.1.0/, Apache-2.0) and
+descript-audio-codec (https://github.com/descriptinc/descript-audio-codec,
+MIT), trimmed to inference-only so the codec loads without external model
+packages. Module attribute paths and weight-norm styles are kept identical
+to upstream so ``codec.pth`` checkpoints load unchanged.
+"""
+
+from vllm_omni.model_executor.models.fish_speech.dac_modules.codec import DAC
+from vllm_omni.model_executor.models.fish_speech.dac_modules.rvq import (
+    DownsampleResidualVectorQuantize,
+)
+from vllm_omni.model_executor.models.fish_speech.dac_modules.transformer import (
+    ModelArgs,
+    WindowLimitedTransformer,
+)
+
+__all__ = [
+    "DAC",
+    "DownsampleResidualVectorQuantize",
+    "ModelArgs",
+    "WindowLimitedTransformer",
+]
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_modules/codec.py b/vllm_omni/model_executor/models/fish_speech/dac_modules/codec.py
new file mode 100644
index 000000000..4bc8483d0
--- /dev/null
+++ b/vllm_omni/model_executor/models/fish_speech/dac_modules/codec.py
@@ -0,0 +1,335 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# Adopted from the fish-speech 0.1.0 PyPI release (Apache-2.0)
+# https://pypi.org/project/fish-speech/0.1.0/
+# Copyright (c) Fish Audio
+"""DAC codec model (encoder / quantizer / decoder).
+
+Differences from upstream ``fish_speech.models.dac.modded_dac.DAC``, none of
+which affect the parameter tree or the inference math:
+
+- Base class is plain ``nn.Module`` instead of ``(audiotools BaseModel,
+  descript CodecMixin)`` -- both bases only add training/CLI conveniences.
+- ``self.delay = self.get_delay()`` (a CodecMixin helper) is dropped; nothing
+  in the inference paths reads it.
+- The training-only ``forward``/``preprocess`` methods are dropped; only
+  ``encode`` and ``decode`` are used at inference time.
+"""
+
+import math
+
+import torch
+from torch import nn
+
+from vllm_omni.model_executor.models.fish_speech.dac_modules.conv import (
+    CausalWNConv1d,
+    CausalWNConvTranspose1d,
+)
+from vllm_omni.model_executor.models.fish_speech.dac_modules.layers import (
+    Snake1d,
+    WNConv1d,
+    WNConvTranspose1d,
+)
+from vllm_omni.model_executor.models.fish_speech.dac_modules.transformer import (
+    ModelArgs,
+    WindowLimitedTransformer,
+)
+
+
+def init_weights(m):
+    if isinstance(m, nn.Conv1d):
+        nn.init.trunc_normal_(m.weight, std=0.02)
+        nn.init.constant_(m.bias, 0)
+
+
+class ResidualUnit(nn.Module):
+    def __init__(self, dim: int = 16, dilation: int = 1, causal: bool = False):
+        super().__init__()
+        conv_class = CausalWNConv1d if causal else WNConv1d
+        pad = ((7 - 1) * dilation) // 2
+        self.block = nn.Sequential(
+            Snake1d(dim),
+            conv_class(dim, dim, kernel_size=7, dilation=dilation, padding=pad),
+            Snake1d(dim),
+            conv_class(dim, dim, kernel_size=1),
+        )
+        self.causal = causal
+
+    def forward(self, x):
+        y = self.block(x)
+        pad = x.shape[-1] - y.shape[-1]
+        if pad > 0:
+            if self.causal:
+                x = x[..., :-pad]
+            else:
+                x = x[..., pad // 2 : -pad // 2]
+        return x + y
+
+
+class EncoderBlock(nn.Module):
+    def __init__(
+        self,
+        dim: int = 16,
+        stride: int = 1,
+        causal: bool = False,
+        n_t_layer: int = 0,
+        transformer_general_config=None,
+    ):
+        super().__init__()
+        conv_class = CausalWNConv1d if causal else WNConv1d
+        transformer_module = (
+            nn.Identity()
+            if n_t_layer == 0
+            else (
+                WindowLimitedTransformer(
+                    causal=causal,
+                    input_dim=dim,
+                    window_size=512,
+                    config=transformer_general_config(
+                        n_layer=n_t_layer,
+                        n_head=dim // 64,
+                        dim=dim,
+                        intermediate_size=dim * 3,
+                    ),
+                )
+            )
+        )
+        self.block = nn.Sequential(
+            ResidualUnit(dim // 2, dilation=1, causal=causal),
+            ResidualUnit(dim // 2, dilation=3, causal=causal),
+            ResidualUnit(dim // 2, dilation=9, causal=causal),
+            Snake1d(dim // 2),
+            conv_class(
+                dim // 2,
+                dim,
+                kernel_size=2 * stride,
+                stride=stride,
+                padding=math.ceil(stride / 2),
+            ),
+            transformer_module,
+        )
+
+    def forward(self, x):
+        return self.block(x)
+
+
+class Encoder(nn.Module):
+    def __init__(
+        self,
+        d_model: int = 64,
+        strides: list = [2, 4, 8, 8],
+        d_latent: int = 64,
+        n_transformer_layers: list = [0, 0, 4, 4],
+        transformer_general_config: ModelArgs = None,
+        causal: bool = False,
+    ):
+        super().__init__()
+        conv_class = CausalWNConv1d if causal else WNConv1d
+        # Create first convolution
+        self.block = [conv_class(1, d_model, kernel_size=7, padding=3)]
+
+        # Create EncoderBlocks that double channels as they downsample by `stride`
+        for stride, n_t_layer in zip(strides, n_transformer_layers):
+            d_model *= 2
+            self.block += [
+                EncoderBlock(
+                    d_model,
+                    stride=stride,
+                    causal=causal,
+                    n_t_layer=n_t_layer,
+                    transformer_general_config=transformer_general_config,
+                )
+            ]
+
+        # Create last convolution
+        self.block += [
+            Snake1d(d_model),
+            conv_class(d_model, d_latent, kernel_size=3, padding=1),
+        ]
+
+        # Wrap black into nn.Sequential
+        self.block = nn.Sequential(*self.block)
+        self.enc_dim = d_model
+
+    def forward(self, x):
+        return self.block(x)
+
+
+class DecoderBlock(nn.Module):
+    def __init__(
+        self,
+        input_dim: int = 16,
+        output_dim: int = 8,
+        stride: int = 1,
+        causal: bool = False,
+        n_t_layer: int = 0,
+        transformer_general_config=None,
+    ):
+        super().__init__()
+        conv_trans_class = CausalWNConvTranspose1d if causal else WNConvTranspose1d
+        # NOTE: upstream constructs a WindowLimitedTransformer from
+        # ``n_t_layer`` here but never registers it (the line placing it in
+        # ``self.block`` is commented out upstream), so decoder blocks carry no
+        # transformer parameters. It is not built here at all -- same module
+        # tree, without allocating throwaway weights.
+        del n_t_layer, transformer_general_config
+        self.block = nn.Sequential(
+            Snake1d(input_dim),
+            conv_trans_class(
+                input_dim,
+                output_dim,
+                kernel_size=2 * stride,
+                stride=stride,
+                padding=math.ceil(stride / 2),
+            ),
+            ResidualUnit(output_dim, dilation=1, causal=causal),
+            ResidualUnit(output_dim, dilation=3, causal=causal),
+            ResidualUnit(output_dim, dilation=9, causal=causal),
+        )
+
+    def forward(self, x):
+        return self.block(x)
+
+
+class Decoder(nn.Module):
+    def __init__(
+        self,
+        input_channel,
+        channels,
+        rates,
+        d_out: int = 1,
+        causal: bool = False,
+        n_transformer_layers: list = [0, 0, 0, 0],
+        transformer_general_config=None,
+    ):
+        super().__init__()
+        conv_class = CausalWNConv1d if causal else WNConv1d
+        # Add first conv layer
+        layers = [conv_class(input_channel, channels, kernel_size=7, padding=3)]
+
+        # Add upsampling + MRF blocks
+        for i, (stride, n_t_layer) in enumerate(zip(rates, n_transformer_layers)):
+            input_dim = channels // 2**i
+            output_dim = channels // 2 ** (i + 1)
+            layers += [
+                DecoderBlock(
+                    input_dim,
+                    output_dim,
+                    stride,
+                    causal=causal,
+                    n_t_layer=n_t_layer,
+                    transformer_general_config=transformer_general_config,
+                )
+            ]
+
+        # Add final conv layer
+        layers += [
+            Snake1d(output_dim),
+            conv_class(output_dim, d_out, kernel_size=7, padding=3),
+            nn.Tanh(),
+        ]
+
+        self.model = nn.Sequential(*layers)
+
+    def forward(self, x):
+        return self.model(x)
+
+
+class DAC(nn.Module):
+    def __init__(
+        self,
+        encoder_dim: int = 64,
+        encoder_rates: list[int] = [2, 4, 8, 8],
+        latent_dim: int = None,
+        decoder_dim: int = 1536,
+        decoder_rates: list[int] = [8, 8, 4, 2],
+        quantizer: torch.nn.Module = None,
+        sample_rate: int = 44100,
+        causal: bool = True,
+        encoder_transformer_layers: list[int] = [0, 0, 0, 0],
+        decoder_transformer_layers: list[int] = [0, 0, 0, 0],
+        transformer_general_config=None,
+    ):
+        super().__init__()
+
+        self.encoder_dim = encoder_dim
+        self.encoder_rates = encoder_rates
+        self.decoder_dim = decoder_dim
+        self.decoder_rates = decoder_rates
+        self.sample_rate = sample_rate
+
+        if latent_dim is None:
+            latent_dim = encoder_dim * (2 ** len(encoder_rates))
+
+        self.latent_dim = latent_dim
+
+        self.hop_length = int(math.prod(encoder_rates))
+        self.encoder = Encoder(
+            encoder_dim,
+            encoder_rates,
+            latent_dim,
+            causal=causal,
+            n_transformer_layers=encoder_transformer_layers,
+            transformer_general_config=transformer_general_config,
+        )
+
+        self.quantizer = quantizer
+
+        self.decoder = Decoder(
+            latent_dim,
+            decoder_dim,
+            decoder_rates,
+            causal=causal,
+            n_transformer_layers=decoder_transformer_layers,
+            transformer_general_config=transformer_general_config,
+        )
+        self.sample_rate = sample_rate
+        self.apply(init_weights)
+
+        self.frame_length = self.hop_length * 4
+
+    def encode(
+        self,
+        audio_data: torch.Tensor,
+        audio_lengths: torch.Tensor = None,
+        n_quantizers: int = None,
+        **kwargs,
+    ):
+        """Encode given audio data and return quantized latent codes.
+
+        Parameters
+        ----------
+        audio_data : Tensor[B x 1 x T]
+            Audio data to encode
+        audio_lengths : Tensor[B], optional
+            Valid sample counts per batch entry
+        n_quantizers : int, optional
+            Number of quantizers to use, by default None (all quantizers)
+
+        Returns
+        -------
+        Tuple of (codes Tensor[B x N x F], code lengths Tensor[B]).
+        """
+        # pad to multiple of self.frame_length
+        if audio_data.ndim == 2:
+            audio_data = audio_data.unsqueeze(1)
+        length = audio_data.shape[-1]
+        right_pad = math.ceil(length / self.frame_length) * self.frame_length - length
+        audio_data = nn.functional.pad(audio_data, (0, right_pad))
+        if audio_lengths is None:
+            audio_lengths = torch.LongTensor([length + right_pad]).to(audio_data.device)
+
+        z = self.encoder(audio_data)
+        vq_results = self.quantizer(z, n_quantizers, **kwargs)
+        indices = vq_results.codes
+        indices_lens = torch.ceil(audio_lengths / self.frame_length).long()
+        return indices, indices_lens
+
+    def decode(self, indices: torch.Tensor, feature_lengths):
+        """Decode codebook indices [B x N x F] to waveform [B x 1 x T]."""
+        if indices.ndim == 2:
+            indices = indices[None]
+
+        z = self.quantizer.decode(indices)
+        audio_lengths = feature_lengths * self.frame_length
+        return self.decoder(z), audio_lengths
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_modules/conv.py b/vllm_omni/model_executor/models/fish_speech/dac_modules/conv.py
new file mode 100644
index 000000000..2b75197a3
--- /dev/null
+++ b/vllm_omni/model_executor/models/fish_speech/dac_modules/conv.py
@@ -0,0 +1,194 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# Adopted from the fish-speech 0.1.0 PyPI release (Apache-2.0)
+# https://pypi.org/project/fish-speech/0.1.0/
+# Copyright (c) Fish Audio
+"""Causal convolution primitives shared by the DAC encoder/decoder and the
+downsample RVQ. Upstream duplicates these between ``modded_dac.py`` and
+``rvq.py``; they are consolidated here (the copies are identical)."""
+
+import math
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from torch.nn.utils.parametrizations import weight_norm
+from torch.nn.utils.parametrize import remove_parametrizations
+
+
+def unpad1d(x: torch.Tensor, paddings: tuple[int, int]):
+    """Remove padding from x, handling properly zero padding. Only for 1d!"""
+    padding_left, padding_right = paddings
+    assert padding_left >= 0 and padding_right >= 0, (padding_left, padding_right)
+    assert (padding_left + padding_right) <= x.shape[-1]
+    end = x.shape[-1] - padding_right
+    return x[..., padding_left:end]
+
+
+def get_extra_padding_for_conv1d(x: torch.Tensor, kernel_size: int, stride: int, padding_total: int = 0) -> int:
+    """See `pad_for_conv1d`."""
+    length = x.shape[-1]
+    n_frames = (length - kernel_size + padding_total) / stride + 1
+    ideal_length = (math.ceil(n_frames) - 1) * stride + (kernel_size - padding_total)
+    return ideal_length - length
+
+
+def pad1d(
+    x: torch.Tensor,
+    paddings: tuple[int, int],
+    mode: str = "zeros",
+    value: float = 0.0,
+):
+    """Tiny wrapper around F.pad, just to allow for reflect padding on small input.
+    If this is the case, we insert extra 0 padding to the right
+    before the reflection happen.
+    """
+    length = x.shape[-1]
+    padding_left, padding_right = paddings
+    assert padding_left >= 0 and padding_right >= 0, (padding_left, padding_right)
+    if mode == "reflect":
+        max_pad = max(padding_left, padding_right)
+        extra_pad = 0
+        if length <= max_pad:
+            extra_pad = max_pad - length + 1
+            x = F.pad(x, (0, extra_pad))
+        padded = F.pad(x, paddings, mode, value)
+        end = padded.shape[-1] - extra_pad
+        return padded[..., :end]
+    else:
+        return F.pad(x, paddings, mode, value)
+
+
+class CausalConvNet(nn.Module):
+    def __init__(
+        self,
+        in_channels,
+        out_channels,
+        kernel_size,
+        dilation=1,
+        stride=1,
+        groups=1,
+        padding=None,
+    ):
+        super().__init__()
+        self.conv = nn.Conv1d(
+            in_channels,
+            out_channels,
+            kernel_size,
+            stride=stride,
+            dilation=dilation,
+            groups=groups,
+        )
+        self.stride = stride
+        self.kernel_size = (kernel_size - 1) * dilation + 1
+        self.dilation = dilation
+        self.padding = self.kernel_size - self.stride
+
+    def forward(self, x):
+        pad = self.padding
+        extra_padding = get_extra_padding_for_conv1d(x, self.kernel_size, self.stride, pad)
+        x = pad1d(x, (pad, extra_padding), mode="constant", value=0)
+        return self.conv(x).contiguous()
+
+    def weight_norm(self, name="weight", dim=0):
+        self.conv = weight_norm(self.conv, name=name, dim=dim)
+        return self
+
+    def remove_weight_norm(self):
+        self.conv = remove_parametrizations(self.conv)
+        return self
+
+
+class CausalTransConvNet(nn.Module):
+    def __init__(self, in_channels, out_channels, kernel_size, dilation=1, stride=1, padding=None):
+        super().__init__()
+        self.conv = nn.ConvTranspose1d(in_channels, out_channels, kernel_size, stride=stride, dilation=dilation)
+        self.stride = stride
+        self.kernel_size = kernel_size
+
+    def forward(self, x):
+        x = self.conv(x)
+        pad = self.kernel_size - self.stride
+        padding_right = math.ceil(pad)
+        padding_left = pad - padding_right
+        x = unpad1d(x, (padding_left, padding_right))
+        return x.contiguous()
+
+    def weight_norm(self, name="weight", dim=0):
+        self.conv = weight_norm(self.conv, name=name, dim=dim)
+        return self
+
+    def remove_weight_norm(self):
+        self.conv = remove_parametrizations(self.conv)
+        return self
+
+
+def CausalWNConv1d(*args, **kwargs):
+    return CausalConvNet(*args, **kwargs).weight_norm()
+
+
+def CausalWNConvTranspose1d(*args, **kwargs):
+    return CausalTransConvNet(*args, **kwargs).weight_norm()
+
+
+class ConvNeXtBlock(nn.Module):
+    r"""ConvNeXt Block. There are two equivalent implementations:
+    (1) DwConv -> LayerNorm (channels_first) -> 1x1 Conv -> GELU -> 1x1 Conv; all in (N, C, H, W)
+    (2) DwConv -> Permute to (N, H, W, C); LayerNorm (channels_last) -> Linear -> GELU -> Linear; Permute back
+    We use (2) as we find it slightly faster in PyTorch
+
+    Args:
+        dim (int): Number of input channels.
+        layer_scale_init_value (float): Init value for Layer Scale. Default: 1e-6.
+        mlp_ratio (float): Ratio of mlp hidden dim to embedding dim. Default: 4.0.
+        kernel_size (int): Kernel size for depthwise conv. Default: 7.
+        dilation (int): Dilation for depthwise conv. Default: 1.
+    """  # noqa: E501
+
+    def __init__(
+        self,
+        dim: int,
+        layer_scale_init_value: float = 1e-6,
+        mlp_ratio: float = 4.0,
+        kernel_size: int = 7,
+        dilation: int = 1,
+    ):
+        super().__init__()
+        convnet_type = CausalConvNet
+        self.dwconv = convnet_type(
+            dim,
+            dim,
+            kernel_size=kernel_size,
+            groups=dim,
+            dilation=dilation,
+        )  # depthwise conv
+        self.norm = nn.LayerNorm(dim, eps=1e-6)
+        # pointwise/1x1 convs, implemented with linear layers
+        self.pwconv1 = nn.Linear(dim, int(mlp_ratio * dim))
+        self.act = nn.GELU()
+        self.pwconv2 = nn.Linear(int(mlp_ratio * dim), dim)
+        self.gamma = (
+            nn.Parameter(layer_scale_init_value * torch.ones(dim), requires_grad=True)
+            if layer_scale_init_value > 0
+            else None
+        )
+
+    def forward(self, x, apply_residual: bool = True):
+        input = x
+
+        x = self.dwconv(x)
+        x = x.permute(0, 2, 1)  # (N, C, L) -> (N, L, C)
+        x = self.norm(x)
+        x = self.pwconv1(x)
+        x = self.act(x)
+        x = self.pwconv2(x)
+
+        if self.gamma is not None:
+            x = self.gamma * x
+
+        x = x.permute(0, 2, 1)  # (N, L, C) -> (N, C, L)
+
+        if apply_residual:
+            x = input + x
+
+        return x
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_modules/layers.py b/vllm_omni/model_executor/models/fish_speech/dac_modules/layers.py
new file mode 100644
index 000000000..9486f6f7a
--- /dev/null
+++ b/vllm_omni/model_executor/models/fish_speech/dac_modules/layers.py
@@ -0,0 +1,238 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# Adopted from https://github.com/descriptinc/descript-audio-codec (MIT License)
+# Copyright (c) 2023-present, Descript
+"""Descript audio codec building blocks (Snake activation, weight-normed convs,
+vector quantizers).
+
+Uses the legacy ``torch.nn.utils.weight_norm`` (``weight_g``/``weight_v`` keys)
+exactly like upstream so quantizer projection weights in ``codec.pth`` load
+unchanged. The ``einops.rearrange`` calls are replaced with equivalent
+reshape/permute ops; ``from_latents`` (training-only) is dropped.
+"""
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from torch.nn.utils import weight_norm
+
+
+def WNConv1d(*args, **kwargs):
+    return weight_norm(nn.Conv1d(*args, **kwargs))
+
+
+def WNConvTranspose1d(*args, **kwargs):
+    return weight_norm(nn.ConvTranspose1d(*args, **kwargs))
+
+
+# Scripting this brings model speed up 1.4x
+@torch.jit.script
+def snake(x, alpha):
+    shape = x.shape
+    x = x.reshape(shape[0], shape[1], -1)
+    x = x + (alpha + 1e-9).reciprocal() * torch.sin(alpha * x).pow(2)
+    x = x.reshape(shape)
+    return x
+
+
+class Snake1d(nn.Module):
+    def __init__(self, channels):
+        super().__init__()
+        self.alpha = nn.Parameter(torch.ones(1, channels, 1))
+
+    def forward(self, x):
+        return snake(x, self.alpha)
+
+
+class VectorQuantize(nn.Module):
+    """
+    Implementation of VQ similar to Karpathy's repo:
+    https://github.com/karpathy/deep-vector-quantization
+    Additionally uses following tricks from Improved VQGAN
+    (https://arxiv.org/pdf/2110.04627.pdf):
+        1. Factorized codes: Perform nearest neighbor lookup in low-dimensional space
+            for improved codebook usage
+        2. l2-normalized codes: Converts euclidean distance to cosine similarity which
+            improves training stability
+    """
+
+    def __init__(self, input_dim: int, codebook_size: int, codebook_dim: int):
+        super().__init__()
+        self.codebook_size = codebook_size
+        self.codebook_dim = codebook_dim
+
+        self.in_proj = WNConv1d(input_dim, codebook_dim, kernel_size=1)
+        self.out_proj = WNConv1d(codebook_dim, input_dim, kernel_size=1)
+        self.codebook = nn.Embedding(codebook_size, codebook_dim)
+
+    def forward(self, z):
+        """Quantized the input tensor using a fixed codebook and returns
+        the corresponding codebook vectors
+
+        Parameters
+        ----------
+        z : Tensor[B x D x T]
+
+        Returns
+        -------
+        Tensor[B x D x T]
+            Quantized continuous representation of input
+        Tensor[1]
+            Commitment loss to train encoder to predict vectors closer to codebook
+            entries
+        Tensor[1]
+            Codebook loss to update the codebook
+        Tensor[B x T]
+            Codebook indices (quantized discrete representation of input)
+        Tensor[B x D x T]
+            Projected latents (continuous representation of input before quantization)
+        """
+
+        # Factorized codes (ViT-VQGAN) Project input into low-dimensional space
+        z_e = self.in_proj(z)  # z_e : (B x D x T)
+        z_q, indices = self.decode_latents(z_e)
+
+        commitment_loss = F.mse_loss(z_e, z_q.detach(), reduction="none").mean([1, 2])
+        codebook_loss = F.mse_loss(z_q, z_e.detach(), reduction="none").mean([1, 2])
+
+        z_q = z_e + (z_q - z_e).detach()  # noop in forward pass, straight-through gradient estimator in backward pass
+
+        z_q = self.out_proj(z_q)
+
+        return z_q, commitment_loss, codebook_loss, indices, z_e
+
+    def embed_code(self, embed_id):
+        return F.embedding(embed_id, self.codebook.weight)
+
+    def decode_code(self, embed_id):
+        return self.embed_code(embed_id).transpose(1, 2)
+
+    def decode_latents(self, latents):
+        batch, dim, time = latents.shape
+        # rearrange "b d t -> (b t) d"
+        encodings = latents.permute(0, 2, 1).reshape(batch * time, dim)
+        codebook = self.codebook.weight  # codebook: (N x D)
+
+        # L2 normalize encodings and codebook (ViT-VQGAN)
+        encodings = F.normalize(encodings)
+        codebook = F.normalize(codebook)
+
+        # Compute euclidean distance with codebook
+        dist = (
+            encodings.pow(2).sum(1, keepdim=True)
+            - 2 * encodings @ codebook.t()
+            + codebook.pow(2).sum(1, keepdim=True).t()
+        )
+        # rearrange "(b t) -> b t"
+        indices = (-dist).max(1)[1].reshape(batch, time)
+        z_q = self.decode_code(indices)
+        return z_q, indices
+
+
+class ResidualVectorQuantize(nn.Module):
+    """
+    Introduced in SoundStream: An end2end neural audio codec
+    https://arxiv.org/abs/2107.03312
+    """
+
+    def __init__(
+        self,
+        input_dim: int = 512,
+        n_codebooks: int = 9,
+        codebook_size: int = 1024,
+        codebook_dim: int | list = 8,
+        quantizer_dropout: float = 0.0,
+    ):
+        super().__init__()
+        if isinstance(codebook_dim, int):
+            codebook_dim = [codebook_dim for _ in range(n_codebooks)]
+
+        self.n_codebooks = n_codebooks
+        self.codebook_dim = codebook_dim
+        self.codebook_size = codebook_size
+
+        self.quantizers = nn.ModuleList(
+            [VectorQuantize(input_dim, codebook_size, codebook_dim[i]) for i in range(n_codebooks)]
+        )
+        self.quantizer_dropout = quantizer_dropout
+
+    def forward(self, z, n_quantizers: int = None):
+        """Quantized the input tensor using a fixed set of `n` codebooks and returns
+        the corresponding codebook vectors
+
+        Parameters
+        ----------
+        z : Tensor[B x D x T]
+        n_quantizers : int, optional
+            No. of quantizers to use
+            (n_quantizers < self.n_codebooks ex: for quantizer dropout)
+            Note: if `self.quantizer_dropout` is True, this argument is ignored
+                when in training mode, and a random number of quantizers is used.
+
+        Returns
+        -------
+        Tuple of (z_q, codes, latents, commitment_loss, codebook_loss).
+        """
+        z_q = 0
+        residual = z
+        commitment_loss = 0
+        codebook_loss = 0
+
+        codebook_indices = []
+        latents = []
+
+        if n_quantizers is None:
+            n_quantizers = self.n_codebooks
+        if self.training:
+            n_quantizers = torch.ones((z.shape[0],)) * self.n_codebooks + 1
+            dropout = torch.randint(1, self.n_codebooks + 1, (z.shape[0],))
+            n_dropout = int(z.shape[0] * self.quantizer_dropout)
+            n_quantizers[:n_dropout] = dropout[:n_dropout]
+            n_quantizers = n_quantizers.to(z.device)
+
+        for i, quantizer in enumerate(self.quantizers):
+            if self.training is False and i >= n_quantizers:
+                break
+
+            z_q_i, commitment_loss_i, codebook_loss_i, indices_i, z_e_i = quantizer(residual)
+
+            # Create mask to apply quantizer dropout
+            mask = torch.full((z.shape[0],), fill_value=i, device=z.device) < n_quantizers
+            z_q = z_q + z_q_i * mask[:, None, None]
+            residual = residual - z_q_i
+
+            # Sum losses
+            commitment_loss += (commitment_loss_i * mask).mean()
+            codebook_loss += (codebook_loss_i * mask).mean()
+
+            codebook_indices.append(indices_i)
+            latents.append(z_e_i)
+
+        codes = torch.stack(codebook_indices, dim=1)
+        latents = torch.cat(latents, dim=1)
+
+        return z_q, codes, latents, commitment_loss, codebook_loss
+
+    def from_codes(self, codes: torch.Tensor):
+        """Given the quantized codes, reconstruct the continuous representation
+
+        Parameters
+        ----------
+        codes : Tensor[B x N x T]
+            Quantized discrete representation of input
+
+        Returns
+        -------
+        Tensor[B x D x T]
+            Quantized continuous representation of input
+        """
+        z_q = 0.0
+        z_p = []
+        n_codebooks = codes.shape[1]
+        for i in range(n_codebooks):
+            z_p_i = self.quantizers[i].decode_code(codes[:, i, :])
+            z_p.append(z_p_i)
+
+            z_q_i = self.quantizers[i].out_proj(z_p_i)
+            z_q = z_q + z_q_i
+        return z_q, torch.cat(z_p, dim=1), codes
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_modules/rvq.py b/vllm_omni/model_executor/models/fish_speech/dac_modules/rvq.py
new file mode 100644
index 000000000..25b0a89ee
--- /dev/null
+++ b/vllm_omni/model_executor/models/fish_speech/dac_modules/rvq.py
@@ -0,0 +1,177 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# Adopted from the fish-speech 0.1.0 PyPI release (Apache-2.0)
+# https://pypi.org/project/fish-speech/0.1.0/
+# Copyright (c) Fish Audio
+"""Downsampled residual vector quantizer (1 semantic + N residual codebooks)."""
+
+from dataclasses import dataclass
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from vllm_omni.model_executor.models.fish_speech.dac_modules.conv import (
+    CausalConvNet,
+    CausalTransConvNet,
+    ConvNeXtBlock,
+)
+from vllm_omni.model_executor.models.fish_speech.dac_modules.layers import (
+    ResidualVectorQuantize,
+)
+
+
+@dataclass
+class VQResult:
+    z: torch.Tensor
+    codes: torch.Tensor
+    latents: torch.Tensor
+    codebook_loss: torch.Tensor
+    commitment_loss: torch.Tensor
+    semantic_distill_z: torch.Tensor | None = None
+
+
+class DownsampleResidualVectorQuantize(nn.Module):
+    def __init__(
+        self,
+        input_dim: int = 1024,
+        n_codebooks: int = 9,
+        codebook_dim: int = 8,
+        quantizer_dropout: float = 0.5,
+        codebook_size: int = 1024,
+        semantic_codebook_size: int = 4096,
+        downsample_factor: tuple[int] = (2, 2),
+        downsample_dims: tuple[int] | None = None,
+        pre_module: nn.Module | None = None,
+        post_module: nn.Module | None = None,
+        semantic_predictor_module: nn.Module | None = None,
+    ):
+        super().__init__()
+
+        if downsample_dims is None:
+            downsample_dims = [input_dim for _ in range(len(downsample_factor))]
+
+        all_dims = (input_dim,) + tuple(downsample_dims)
+
+        self.semantic_quantizer = ResidualVectorQuantize(
+            input_dim=input_dim,
+            n_codebooks=1,
+            codebook_size=semantic_codebook_size,
+            codebook_dim=codebook_dim,
+            quantizer_dropout=0.0,
+        )
+
+        self.quantizer = ResidualVectorQuantize(
+            input_dim=input_dim,
+            n_codebooks=n_codebooks,
+            codebook_size=codebook_size,
+            codebook_dim=codebook_dim,
+            quantizer_dropout=quantizer_dropout,
+        )
+
+        self.downsample_factor = downsample_factor
+        self.downsample_dims = downsample_dims
+
+        convnet_type = CausalConvNet
+        transconvnet_type = CausalTransConvNet
+
+        self.downsample = nn.Sequential(
+            *[
+                nn.Sequential(
+                    convnet_type(
+                        all_dims[idx],
+                        all_dims[idx + 1],
+                        kernel_size=factor,
+                        stride=factor,
+                    ),
+                    ConvNeXtBlock(dim=all_dims[idx + 1]),
+                )
+                for idx, factor in enumerate(downsample_factor)
+            ]
+        )
+
+        self.upsample = nn.Sequential(
+            *[
+                nn.Sequential(
+                    transconvnet_type(
+                        all_dims[idx + 1],
+                        all_dims[idx],
+                        kernel_size=factor,
+                        stride=factor,
+                    ),
+                    ConvNeXtBlock(dim=all_dims[idx]),
+                )
+                for idx, factor in reversed(list(enumerate(downsample_factor)))
+            ]
+        )
+        self.apply(self._init_weights)
+        # leave for transformer, LSTM or Mamba or something else
+        self.pre_module = pre_module if pre_module is not None else nn.Identity()
+        self.post_module = post_module if post_module is not None else nn.Identity()
+        self.semantic_predictor_module = (
+            semantic_predictor_module if semantic_predictor_module is not None else nn.Identity()
+        )
+
+    def _init_weights(self, m):
+        if isinstance(m, (nn.Conv1d, nn.Linear)):
+            nn.init.trunc_normal_(m.weight, std=0.02)
+            nn.init.constant_(m.bias, 0)
+
+    def forward(self, z, n_quantizers: int = None, semantic_len: torch.Tensor = None, **kwargs):
+        # z: (B, D, T)
+        original_shape = z.shape
+        if semantic_len is None:
+            semantic_len = torch.LongTensor([z.shape[-1]])
+        z = self.downsample(z)
+        z = self.pre_module(z)  # B, T, D
+        (
+            semantic_z,
+            semantic_codes,
+            semantic_latents,
+            semantic_commitment_loss,
+            semantic_codebook_loss,
+        ) = self.semantic_quantizer(z)
+        residual_z = z - semantic_z
+        residual_z, codes, latents, commitment_loss, codebook_loss = self.quantizer(
+            residual_z, n_quantizers=n_quantizers
+        )
+        z = semantic_z + residual_z
+        commitment_loss = commitment_loss + semantic_commitment_loss
+        codebook_loss = codebook_loss + semantic_codebook_loss
+        codes = torch.cat([semantic_codes, codes], dim=1)
+        latents = torch.cat([semantic_latents, latents], dim=1)
+        z = self.post_module(z)
+        z = self.upsample(z)
+        # z: (B, D, T)
+
+        # Pad or crop z to match original shape
+        diff = original_shape[-1] - z.shape[-1]
+        right = 0
+        left = abs(diff) - right
+
+        if diff > 0:
+            z = F.pad(z, (left, right))
+        elif diff < 0:
+            z = z[..., left:]
+
+        results = VQResult(
+            z=z,
+            codes=codes,
+            latents=latents,
+            commitment_loss=commitment_loss,
+            codebook_loss=codebook_loss,
+        )
+
+        return results
+
+    def decode(self, indices: torch.Tensor):
+        new_indices = torch.zeros_like(indices)
+        new_indices[:, 0] = torch.clamp(indices[:, 0], max=self.semantic_quantizer.codebook_size - 1)
+        new_indices[:, 1:] = torch.clamp(indices[:, 1:], max=self.quantizer.codebook_size - 1)
+
+        z_q_semantic = self.semantic_quantizer.from_codes(new_indices[:, :1])[0]
+        z_q_residual = self.quantizer.from_codes(new_indices[:, 1:])[0]
+        z_q = z_q_semantic + z_q_residual
+        z_q = self.post_module(z_q)
+        z_q = self.upsample(z_q)
+        return z_q
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_modules/transformer.py b/vllm_omni/model_executor/models/fish_speech/dac_modules/transformer.py
new file mode 100644
index 000000000..cb9521287
--- /dev/null
+++ b/vllm_omni/model_executor/models/fish_speech/dac_modules/transformer.py
@@ -0,0 +1,419 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# Adopted from the fish-speech 0.1.0 PyPI release (Apache-2.0)
+# https://pypi.org/project/fish-speech/0.1.0/
+# Copyright (c) Fish Audio
+"""Window-limited transformer used inside the DAC codec (encoder blocks,
+decoder blocks, and RVQ pre/post modules)."""
+
+import math
+from dataclasses import dataclass
+
+import torch
+from torch import Tensor, nn
+from torch.nn import functional as F
+
+
+def find_multiple(n: int, k: int) -> int:
+    if n % k == 0:
+        return n
+    return n + k - (n % k)
+
+
+@dataclass
+class ModelArgs:
+    block_size: int = 2048
+    n_layer: int = 8
+    n_head: int = 8
+    dim: int = 512
+    intermediate_size: int = 1536
+    n_local_heads: int = -1
+    head_dim: int = 64
+    rope_base: float = 10000
+    norm_eps: float = 1e-5
+    dropout_rate: float = 0.1
+    attn_dropout_rate: float = 0.1
+    channels_first: bool = True  # to be compatible with conv1d input/output
+    pos_embed_type: str = "rope"  # can be "rope" or "conformer"
+    max_relative_position: int = 128  # for conformer-style relative position embedding
+
+    def __post_init__(self):
+        if self.n_local_heads == -1:
+            self.n_local_heads = self.n_head
+        if self.intermediate_size is None:
+            hidden_dim = 4 * self.dim
+            n_hidden = int(2 * hidden_dim / 3)
+            self.intermediate_size = find_multiple(n_hidden, 256)
+        assert self.pos_embed_type in [
+            "rope",
+            "conformer",
+        ], "pos_embed_type must be either 'rope' or 'conformer'"
+
+
+class KVCache(nn.Module):
+    def __init__(self, max_batch_size, max_seq_length, n_heads, head_dim, dtype=torch.bfloat16):
+        super().__init__()
+        cache_shape = (max_batch_size, n_heads, max_seq_length, head_dim)
+        self.register_buffer("k_cache", torch.zeros(cache_shape, dtype=dtype))
+        self.register_buffer("v_cache", torch.zeros(cache_shape, dtype=dtype))
+
+    def update(self, input_pos, k_val, v_val):
+        # input_pos: [S], k_val: [B, H, S, D]
+        assert input_pos.shape[0] == k_val.shape[2]
+
+        k_out = self.k_cache
+        v_out = self.v_cache
+        k_out[:, :, input_pos] = k_val
+        v_out[:, :, input_pos] = v_val
+
+        return (
+            k_out[:, :, : input_pos.max() + 1, :],
+            v_out[:, :, : input_pos.max() + 1, :],
+        )
+
+    def clear_cache(self, prompt_len):
+        self.k_cache[:, :, prompt_len:, :].fill_(0)
+        self.v_cache[:, :, prompt_len:, :].fill_(0)
+
+
+class Transformer(nn.Module):
+    def __init__(self, config: ModelArgs) -> None:
+        super().__init__()
+        self.config = config
+
+        self.layers = nn.ModuleList(TransformerBlock(config) for _ in range(config.n_layer))
+        self.norm = RMSNorm(config.dim, eps=config.norm_eps)
+
+        # Only compute RoPE frequencies if using RoPE
+        if config.pos_embed_type == "rope":
+            freqs_cis = precompute_freqs_cis(self.config.block_size, self.config.head_dim, self.config.rope_base)
+            self.register_buffer("freqs_cis", freqs_cis)
+        else:
+            self.register_buffer("freqs_cis", None)
+
+        causal_mask = torch.tril(torch.ones(self.config.block_size, self.config.block_size, dtype=torch.bool))
+        self.register_buffer("causal_mask", causal_mask)
+
+        self.max_batch_size = -1
+        self.max_seq_length = -1
+        self.use_kv_cache = False
+
+    def setup_caches(self, max_batch_size, max_seq_length):
+        """
+        This method will only be called during inference when using KV cache.
+        """
+        head_dim = self.config.dim // self.config.n_head
+        max_seq_length = find_multiple(max_seq_length, 8)
+        self.max_seq_length = max_seq_length
+        self.max_batch_size = max_batch_size
+        dtype = self.norm.weight.dtype
+        device = self.norm.weight.device
+
+        for b in self.layers:
+            b.attention.kv_cache = KVCache(
+                max_batch_size,
+                max_seq_length,
+                self.config.n_local_heads,
+                head_dim,
+                dtype,
+            ).to(device)
+
+        self.use_kv_cache = True
+
+    def forward(
+        self,
+        x: Tensor,
+        input_pos: Tensor | None = None,
+        mask: Tensor | None = None,
+    ) -> Tensor:
+        if self.config.pos_embed_type == "rope":
+            assert self.freqs_cis is not None, "RoPE frequencies must be initialized for RoPE positional embedding"
+            freqs_cis = self.freqs_cis[input_pos]
+        else:
+            freqs_cis = None
+
+        if mask is None:  # in case of non-causal model
+            if not self.training and self.use_kv_cache:
+                mask = self.causal_mask[None, None, input_pos]
+                mask = mask[..., : input_pos.max() + 1]
+            else:
+                mask = self.causal_mask[None, None, input_pos]
+                mask = mask[..., input_pos]
+
+        for i, layer in enumerate(self.layers):
+            x = layer(x, input_pos, freqs_cis, mask)
+        x = self.norm(x)
+        return x
+
+
+class TransformerBlock(nn.Module):
+    def __init__(self, config: ModelArgs) -> None:
+        super().__init__()
+        self.attention = Attention(config)
+        self.feed_forward = FeedForward(config)
+        self.ffn_norm = RMSNorm(config.dim, eps=config.norm_eps)
+        self.attention_norm = RMSNorm(config.dim, eps=config.norm_eps)
+        self.attention_layer_scale = LayerScale(config.dim, inplace=True)
+        self.ffn_layer_scale = LayerScale(config.dim, inplace=True)
+
+    def forward(
+        self,
+        x: Tensor,
+        input_pos: Tensor,
+        freqs_cis: Tensor,
+        mask: Tensor,
+    ) -> Tensor:
+        h = x + self.attention_layer_scale(self.attention(self.attention_norm(x), freqs_cis, mask, input_pos))
+        out = h + self.ffn_layer_scale(self.feed_forward(self.ffn_norm(h)))
+        return out
+
+
+class Attention(nn.Module):
+    def __init__(self, config: ModelArgs):
+        super().__init__()
+        assert config.dim % config.n_head == 0
+
+        total_head_dim = (config.n_head + 2 * config.n_local_heads) * config.head_dim
+        # key, query, value projections for all heads, but in a batch
+        self.wqkv = nn.Linear(config.dim, total_head_dim, bias=False)
+        self.wo = nn.Linear(config.head_dim * config.n_head, config.dim, bias=False)
+        self.kv_cache = None
+
+        self.n_head = config.n_head
+        self.head_dim = config.head_dim
+        self.n_local_heads = config.n_local_heads
+        self.dim = config.dim
+        self.attn_dropout_rate = config.attn_dropout_rate
+        self.pos_embed_type = config.pos_embed_type
+
+        # Add relative position embedding for conformer-style
+        if self.pos_embed_type == "conformer":
+            self.max_relative_position = config.max_relative_position
+            num_pos_embeddings = 2 * config.max_relative_position + 1
+            self.rel_pos_embeddings = nn.Parameter(torch.zeros(num_pos_embeddings, self.head_dim))
+            nn.init.normal_(self.rel_pos_embeddings, mean=0.0, std=0.02)
+
+    def _compute_conformer_pos_scores(self, q: Tensor, seqlen: int) -> Tensor:
+        # q: [B, H, S, D]
+        # Returns: [B, H, S, S]
+        positions = torch.arange(seqlen, device=q.device)
+        relative_positions = positions.unsqueeze(1) - positions.unsqueeze(0)  # [S, S]
+        relative_positions = torch.clamp(
+            relative_positions + self.max_relative_position,
+            0,
+            2 * self.max_relative_position,
+        )
+        rel_embeddings = self.rel_pos_embeddings[relative_positions]  # [S, S, D]
+
+        # Compute attention scores with relative position embeddings
+        q = q.transpose(1, 2)  # [B, S, H, D]
+        rel_logits = torch.matmul(q, rel_embeddings.transpose(-2, -1))  # [B, S, H, S]
+        rel_logits = rel_logits.transpose(1, 2)  # [B, H, S, S]
+        return rel_logits
+
+    def forward(
+        self,
+        x: Tensor,
+        freqs_cis: Tensor,
+        mask: Tensor,
+        input_pos: Tensor | None = None,
+    ) -> Tensor:
+        bsz, seqlen, _ = x.shape
+
+        kv_size = self.n_local_heads * self.head_dim
+        q, k, v = self.wqkv(x).split([kv_size, kv_size, kv_size], dim=-1)
+        context_seqlen = seqlen
+
+        q = q.view(bsz, seqlen, self.n_head, self.head_dim)
+        k = k.view(bsz, context_seqlen, self.n_local_heads, self.head_dim)
+        v = v.view(bsz, context_seqlen, self.n_local_heads, self.head_dim)
+
+        if self.pos_embed_type == "rope":
+            q = apply_rotary_emb(q, freqs_cis)
+            k = apply_rotary_emb(k, freqs_cis)
+
+        q, k, v = map(lambda x: x.transpose(1, 2), (q, k, v))
+
+        if self.kv_cache is not None:
+            k, v = self.kv_cache.update(input_pos, k, v)
+
+        k = k.repeat_interleave(self.n_head // self.n_local_heads, dim=1)
+        v = v.repeat_interleave(self.n_head // self.n_local_heads, dim=1)
+
+        if self.pos_embed_type == "conformer":
+            # Compute attention scores
+            scale = 1.0 / math.sqrt(self.head_dim)
+            scores = torch.matmul(q, k.transpose(-2, -1)) * scale
+
+            # Add relative position embeddings for conformer-style
+            rel_scores = self._compute_conformer_pos_scores(q, seqlen)
+            scores = scores + rel_scores
+
+            # Apply attention
+            if mask is not None:
+                scores = scores.masked_fill(~mask, float("-inf"))
+
+            attn = F.softmax(scores, dim=-1)
+            if self.attn_dropout_rate > 0 and self.training:
+                attn = F.dropout(attn, p=self.attn_dropout_rate)
+
+            y = torch.matmul(attn, v)
+        else:
+            y = F.scaled_dot_product_attention(
+                q,
+                k,
+                v,
+                dropout_p=self.attn_dropout_rate if self.training else 0.0,
+                attn_mask=mask,
+            )
+        y = y.transpose(1, 2).contiguous().view(bsz, seqlen, self.head_dim * self.n_head)
+        y = self.wo(y)
+        return y
+
+
+class FeedForward(nn.Module):
+    def __init__(self, config: ModelArgs) -> None:
+        super().__init__()
+        self.w1 = nn.Linear(config.dim, config.intermediate_size, bias=False)
+        self.w3 = nn.Linear(config.dim, config.intermediate_size, bias=False)
+        self.w2 = nn.Linear(config.intermediate_size, config.dim, bias=False)
+        self.dropout = nn.Dropout(config.dropout_rate)
+
+    def forward(self, x: Tensor) -> Tensor:
+        return self.w2(self.dropout(F.silu(self.w1(x)) * self.w3(x)))
+
+
+class RMSNorm(nn.Module):
+    def __init__(self, dim: int, eps: float = 1e-5):
+        super().__init__()
+        self.eps = eps
+        self.weight = nn.Parameter(torch.ones(dim))
+
+    def _norm(self, x):
+        return x * torch.rsqrt(torch.mean(x * x, dim=-1, keepdim=True) + self.eps)
+
+    def forward(self, x: Tensor) -> Tensor:
+        output = self._norm(x.float()).type_as(x)
+        return output * self.weight
+
+
+class LayerScale(nn.Module):
+    def __init__(
+        self,
+        dim: int,
+        init_values: float | Tensor = 1e-2,
+        inplace: bool = False,
+    ) -> None:
+        super().__init__()
+        self.inplace = inplace
+        self.gamma = nn.Parameter(init_values * torch.ones(dim))
+
+    def forward(self, x: Tensor) -> Tensor:
+        return x.mul_(self.gamma) if self.inplace else x * self.gamma
+
+
+class WindowLimitedTransformer(Transformer):
+    """
+    Transformer with window limited attention, causal.
+    """
+
+    def __init__(
+        self,
+        config: ModelArgs,
+        input_dim: int = 512,
+        window_size: int | None = None,
+        causal: bool = True,
+        look_ahead_conv: nn.Module = None,
+    ):
+        super().__init__(config)
+        self.window_size = window_size
+        self.causal = causal
+        self.channels_first = config.channels_first
+        self.look_ahead_conv = look_ahead_conv if look_ahead_conv is not None else nn.Identity()
+        self.input_proj = nn.Linear(input_dim, config.dim) if input_dim != config.dim else nn.Identity()
+        self.output_proj = nn.Linear(config.dim, input_dim) if input_dim != config.dim else nn.Identity()
+
+    def make_window_limited_mask(
+        self,
+        max_length: int,
+        x_lens: Tensor | None = None,
+    ) -> Tensor:
+        """
+        Make mask to form window limited attention.
+        """
+        if self.causal:
+            mask = torch.tril(torch.ones(max_length, max_length))
+            row_indices = torch.arange(max_length).view(-1, 1)
+            window_size = self.window_size or max_length
+            valid_range = (row_indices - window_size + 1).clamp(min=0)
+            column_indices = torch.arange(max_length)
+            mask = (column_indices >= valid_range) & mask.bool()
+        else:
+            raise NotImplementedError
+        mask = mask.bool()[None, None]
+        return mask
+
+    def make_mask(
+        self,
+        max_length: int,
+        x_lens: Tensor | None = None,
+    ) -> Tensor:
+        """
+        Make ordinary mask if window size is not specified.
+        """
+        if self.causal:
+            mask = torch.tril(torch.ones(max_length, max_length))
+        else:
+            mask = torch.ones(max_length, max_length)
+            mask = mask.bool()[None, None]
+            for i, x_len in enumerate(x_lens):
+                mask[:x_len, i] = 0
+        mask = mask.bool()[None, None]
+        return mask
+
+    def forward(
+        self,
+        x: Tensor,
+        x_lens: Tensor | None = None,
+    ) -> Tensor:
+        if self.channels_first:
+            x = x.transpose(1, 2)
+        x = self.input_proj(x)  # (B, T, D)
+        x = self.look_ahead_conv(x)
+        input_pos = torch.arange(x.shape[1], device=x.device)
+        # construct mask to form window limited attention
+        max_length = x.shape[1]
+        if self.window_size is not None:
+            mask = self.make_window_limited_mask(max_length, x_lens)
+        else:
+            mask = self.make_mask(max_length, x_lens)
+        mask = mask.to(x.device)
+        x = super().forward(x, input_pos, mask)
+        x = self.output_proj(x)  # (B, T, D)
+        if self.channels_first:
+            x = x.transpose(1, 2)
+        return x
+
+
+def precompute_freqs_cis(seq_len: int, n_elem: int, base: int = 10000, dtype: torch.dtype = torch.bfloat16) -> Tensor:
+    freqs = 1.0 / (base ** (torch.arange(0, n_elem, 2)[: (n_elem // 2)].float() / n_elem))
+    t = torch.arange(seq_len, device=freqs.device)
+    freqs = torch.outer(t, freqs)
+    freqs_cis = torch.polar(torch.ones_like(freqs), freqs)
+    cache = torch.stack([freqs_cis.real, freqs_cis.imag], dim=-1)
+    return cache.to(dtype=dtype)
+
+
+def apply_rotary_emb(x: Tensor, freqs_cis: Tensor) -> Tensor:
+    xshaped = x.float().reshape(*x.shape[:-1], -1, 2)
+    freqs_cis = freqs_cis.view(1, xshaped.size(1), 1, xshaped.size(3), 2)
+    x_out2 = torch.stack(
+        [
+            xshaped[..., 0] * freqs_cis[..., 0] - xshaped[..., 1] * freqs_cis[..., 1],
+            xshaped[..., 1] * freqs_cis[..., 0] + xshaped[..., 0] * freqs_cis[..., 1],
+        ],
+        -1,
+    )
+
+    x_out2 = x_out2.flatten(3)
+    return x_out2.type_as(x)
diff --git a/vllm_omni/model_executor/models/fish_speech/dac_utils.py b/vllm_omni/model_executor/models/fish_speech/dac_utils.py
index f1f2590a3..b0d04e086 100644
--- a/vllm_omni/model_executor/models/fish_speech/dac_utils.py
+++ b/vllm_omni/model_executor/models/fish_speech/dac_utils.py
@@ -19,12 +19,12 @@ def build_dac_codec() -> nn.Module:
     Returns the model on CPU in eval mode -- caller is responsible for
     loading weights and moving to the target device.
     """
-    from fish_speech.models.dac.modded_dac import (
+    from vllm_omni.model_executor.models.fish_speech.dac_modules import (
         DAC,
+        DownsampleResidualVectorQuantize,
         ModelArgs,
         WindowLimitedTransformer,
     )
-    from fish_speech.models.dac.rvq import DownsampleResidualVectorQuantize
 
     base_transformer_kwargs = dict(
         block_size=16384,
diff --git a/vllm_omni/model_executor/models/fish_speech/fish_speech_dac_decoder.py b/vllm_omni/model_executor/models/fish_speech/fish_speech_dac_decoder.py
index 9627dc7ce..984d3f638 100644
--- a/vllm_omni/model_executor/models/fish_speech/fish_speech_dac_decoder.py
+++ b/vllm_omni/model_executor/models/fish_speech/fish_speech_dac_decoder.py
@@ -5,8 +5,8 @@ Loads the DAC codec from ``codec.pth`` and decodes codebook indices
 
 Analogous to ``Qwen3TTSCode2Wav`` in qwen3_tts.
 
-Requires the ``fish-speech`` package for the DAC model architecture.
-Install with: ``pip install fish-speech``
+The DAC model architecture is vendored in ``dac_modules`` -- no external
+``fish-speech`` package is required.
 """
 
 from __future__ import annotations