[Perf][Ming-TTS] Add initial latent chunk for lower streaming TTFP (#5011)

Signed-off-by: LHXuuu <xulianhao.xlh@antgroup.com>

vllm_omni/model_executor/models/ming_tts/config_ming_tts.py

@@ -22,6 +22,7 @@ from .constants import (
     DEFAULT_SIGMA,
     DEFAULT_TEMPERATURE,
     HISTORY_PATCH_SIZE,
+    INITIAL_LATENT_CHUNK_SIZE,
     KEY_CFG,
     KEY_CHUNK_ID,
     KEY_DECODE_STEP,
@@ -239,6 +240,7 @@ class MingTTSConfig:
     max_decode_steps: int = MAX_DECODE_STEPS
 
     latent_chunk_size: int = LATENT_CHUNK_SIZE
+    initial_latent_chunk_size: int = INITIAL_LATENT_CHUNK_SIZE
     latent_left_context: int = LATENT_LEFT_CONTEXT
 
     text_eos_token_id: int = TEXT_EOS_TOKEN_ID

vllm_omni/model_executor/models/ming_tts/constants.py

@@ -58,6 +58,7 @@ DEFAULT_TEMPERATURE = 0.0
 
 # Connector / Stage-2 streaming defaults (runtime tuning)
 LATENT_CHUNK_SIZE = 25
+INITIAL_LATENT_CHUNK_SIZE = 4
 LATENT_LEFT_CONTEXT = 0
 MAX_DECODE_STEPS = 200
 

vllm_omni/model_executor/models/ming_tts/validation.py

@@ -172,6 +172,9 @@ def validate_ming_tts_config(cfg: Any) -> None:
 
     if cfg.latent_chunk_size <= 0:
         raise ValueError(f"latent_chunk_size must be > 0, got {cfg.latent_chunk_size}.")
+    initial_latent_chunk_size = getattr(cfg, "initial_latent_chunk_size", 0)
+    if initial_latent_chunk_size < 0:
+        raise ValueError(f"initial_latent_chunk_size must be >= 0, got {initial_latent_chunk_size}.")
     if cfg.latent_left_context < 0:
         raise ValueError(f"latent_left_context must be >= 0, got {cfg.latent_left_context}.")
     if cfg.max_decode_steps <= 0: