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rocm-chatterbox-whisper/engine.py
scott 29b66e24bb
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Cache voice conditionals and add FP16 autocast
Voice conditionals (s3tokenizer + voice encoder + mel embeddings) are
expensive to compute but depend only on the reference audio, not the
text. Previously they ran on every synthesis chunk — 3x wasted work for
a 3-chunk request. Now computed once at startup and reused.

Also wrap generate() in torch.amp.autocast(float16) for ~2x speedup on
all model computation (T3 LLM, S3Gen CFM, HiFiGAN vocoder).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-05 20:22:13 -04:00

127 lines
3.8 KiB
Python

import logging
import torch
from typing import Optional, Tuple
logger = logging.getLogger(__name__)
chatterbox_model = None
_sample_rate = 24000
_is_turbo = False
# Cache: voice file path → prepared conditionals object.
# prepare_conditionals loads audio, runs s3tokenizer + voice encoder, and
# builds mel embeddings — expensive work that only depends on the reference
# audio, not the text. Cache it so multi-chunk requests pay the cost once.
_cond_cache: dict = {}
def _test_cuda() -> bool:
try:
if torch.cuda.is_available():
torch.zeros(1).cuda()
return True
except Exception:
pass
return False
def detect_device() -> str:
return "cuda" if _test_cuda() else "cpu"
def load_model() -> bool:
global chatterbox_model, _sample_rate, _is_turbo
from config import get_model_repo_id, get_device_override
device = get_device_override() or detect_device()
repo_id = get_model_repo_id()
logger.info(f"Loading model '{repo_id}' on device '{device}'")
try:
if "turbo" in repo_id.lower():
from chatterbox.tts_turbo import ChatterboxTurboTTS
chatterbox_model = ChatterboxTurboTTS.from_pretrained(device)
_is_turbo = True
else:
from chatterbox.tts import ChatterboxTTS
chatterbox_model = ChatterboxTTS.from_pretrained(device)
_is_turbo = False
_sample_rate = 24000
logger.info("Model loaded successfully")
return True
except Exception:
logger.exception("Failed to load model")
return False
def prepare_voice(audio_prompt_path: str) -> None:
"""
Pre-compute and cache the voice conditionals for a reference audio file.
Calling this once avoids repeating the s3tokenizer + voice encoder work
on every synthesis chunk that uses the same voice.
"""
if chatterbox_model is None:
return
if audio_prompt_path in _cond_cache:
return
if not _is_turbo:
return # only turbo exposes prepare_conditionals
logger.info(f"Preparing voice conditionals for '{audio_prompt_path}'")
with torch.inference_mode():
chatterbox_model.prepare_conditionals(audio_prompt_path)
_cond_cache[audio_prompt_path] = chatterbox_model.conds
logger.info("Voice conditionals cached")
def get_sample_rate() -> int:
return _sample_rate
def synthesize(
text: str,
audio_prompt_path: Optional[str] = None,
exaggeration: float = 0.5,
cfg_weight: float = 0.5,
temperature: float = 0.8,
seed: int = 0,
) -> Tuple[torch.Tensor, int]:
if chatterbox_model is None:
raise RuntimeError("Model not loaded. Call load_model() first.")
if seed > 0:
torch.manual_seed(seed)
if torch.cuda.is_available():
torch.cuda.manual_seed_all(seed)
# Restore cached conditionals so generate() skips prepare_conditionals.
if audio_prompt_path and _is_turbo:
if audio_prompt_path not in _cond_cache:
prepare_voice(audio_prompt_path)
chatterbox_model.conds = _cond_cache[audio_prompt_path]
kwargs: dict = {}
# Don't pass audio_prompt_path — conds are already set above.
# For non-turbo models there's no cache, pass path as normal.
if audio_prompt_path and not _is_turbo:
kwargs["audio_prompt_path"] = audio_prompt_path
if _is_turbo:
kwargs["temperature"] = temperature
else:
kwargs["exaggeration"] = exaggeration
kwargs["cfg_weight"] = cfg_weight
with torch.inference_mode():
with torch.amp.autocast(device_type="cuda", dtype=torch.float16):
wav = chatterbox_model.generate(text=text, **kwargs)
if torch.cuda.is_available():
torch.cuda.synchronize()
torch.cuda.empty_cache()
return wav, _sample_rate