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vibepod/server/vibevoice_server.py
T
google-labs-jules[bot] 09d9727c20 🧹 Refactor model loading in vibevoice_server.py
🎯 What: Extracted inline model loading logic from `_load_model_sync` into distinct helper functions (`_init_processor`, `_init_model`, and `_load_voice_presets`).
💡 Why: This significantly reduces the complexity of `_load_model_sync`, making the code easier to read and maintain.
 Verification: Ran a syntax check (`python -m py_compile`), started the backend server with CPU inference, and verified the model initialized and correctly processed a text-to-speech request to the `/generate` endpoint without regressions.
 Result: Improved code modularity while preserving identical behavior.

Co-authored-by: LyAhn <27559362+LyAhn@users.noreply.github.com>
2026-04-28 16:35:26 +00:00

410 lines
14 KiB
Python

"""
VibePod — VibeVoice FastAPI TTS Server
Startup sequence (background thread):
1. Download model weights if not cached -> status: downloading
2. Download voice preset .pt files -> status: loading
3. Load processor + model into memory -> status: loading
4. Pre-load all voice tensors -> status: loading
-> Server ready -> status: online
Generation flow:
POST /generate -> SSE stream of audio_chunk events (base64 float32 PCM),
ends with {type:"complete"}
Device selection:
Set VIBEPOD_DEVICE=cpu to force CPU inference (e.g. via --cpu flag in start.sh).
Set VIBEPOD_DEVICE=cuda to force CUDA (default when a GPU is available).
If unset, the server auto-detects: CUDA if available, otherwise CPU.
"""
import asyncio
import base64
import copy
import functools
import json
import logging
import os
import threading
import time
import urllib.request
from contextlib import asynccontextmanager
from pathlib import Path
from typing import AsyncGenerator, Literal, Optional
import torch
from fastapi import FastAPI, HTTPException, Request
from fastapi.responses import StreamingResponse
from pydantic import BaseModel, Field, field_validator
from tqdm import tqdm as _BaseTqdm
logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(message)s")
logger = logging.getLogger(__name__)
MODEL_ID = "microsoft/VibeVoice-Realtime-0.5B"
SAMPLE_RATE = 24_000
VOICES_DIR = Path(__file__).parent / "voices" / "streaming_model"
VOICE_BASE_URL = (
"https://raw.githubusercontent.com/microsoft/VibeVoice/main"
"/demo/voices/streaming_model"
)
EN_VOICES: dict[str, str] = {
"carter": "en-Carter_man.pt",
"davis": "en-Davis_man.pt",
"emma": "en-Emma_woman.pt",
"frank": "en-Frank_man.pt",
"grace": "en-Grace_woman.pt",
"mike": "en-Mike_man.pt",
}
DEFAULT_SPEAKER = "carter"
_IGNORE_PATTERNS = ["*.msgpack", "flax_model*", "tf_model*", "rust_model*", "*.ot"]
# ── Device selection ────────────────────────────────────────────────────────────
# VIBEPOD_DEVICE env var is set by start.sh based on the --cpu / --cuda flag.
# Falls back to auto-detection if not set.
def _resolve_device() -> str:
"""Resolve the target device from env var or auto-detect."""
env = os.environ.get("VIBEPOD_DEVICE", "").strip().lower()
if env in ("cpu", "cuda"):
if env == "cuda" and not torch.cuda.is_available():
logger.warning(
"VIBEPOD_DEVICE=cuda requested but CUDA is not available — falling back to CPU."
)
return "cpu"
return env
# Auto-detect
return "cuda" if torch.cuda.is_available() else "cpu"
# ── Global state ────────────────────────────────────────────────────────────────
ModelStatus = Literal["downloading", "loading", "online", "error"]
_processor = None
_model = None
_device: str = "cpu"
_model_status: ModelStatus = "loading"
_model_error: Optional[str] = None
_voice_presets: dict[str, object] = {}
_load_lock = threading.Lock()
_generation_lock = asyncio.Lock()
# Download progress (files downloaded so far)
_dl_progress: dict[str, int] = {"done": 0, "total": 0}
# ── Progress-tracking tqdm (for model file downloads) ──────────────────────────
def _make_dl_tqdm() -> type:
class _DlTqdm(_BaseTqdm):
def __init__(self, *args: object, **kwargs: object) -> None:
super().__init__(*args, **kwargs)
if isinstance(self.total, (int, float)) and 0 < self.total < 10_000:
_dl_progress["total"] = int(self.total)
_dl_progress["done"] = 0
def update(self, n: int = 1) -> "bool | None":
result = super().update(n)
if isinstance(self.total, (int, float)) and 0 < self.total < 10_000:
_dl_progress["done"] = int(self.n)
return result
return _DlTqdm
# ── Model / voice helpers ───────────────────────────────────────────────────────
def _is_model_cached() -> bool:
try:
from huggingface_hub import snapshot_download
snapshot_download(MODEL_ID, local_files_only=True, ignore_patterns=_IGNORE_PATTERNS)
return True
except Exception:
return False
def _download_model() -> None:
from huggingface_hub import snapshot_download
token: Optional[str] = os.environ.get("HF_TOKEN") or os.environ.get("HUGGINGFACE_TOKEN")
DlTqdm = _make_dl_tqdm()
logger.info("Model not cached — downloading %s...", MODEL_ID)
snapshot_download(
repo_id=MODEL_ID,
ignore_patterns=_IGNORE_PATTERNS,
token=token or None,
tqdm_class=DlTqdm,
)
logger.info("Model download complete.")
def _download_voices() -> None:
VOICES_DIR.mkdir(parents=True, exist_ok=True)
for name, filename in EN_VOICES.items():
dest = VOICES_DIR / filename
if not dest.exists():
url = f"{VOICE_BASE_URL}/{filename}"
logger.info("Downloading voice preset: %s", filename)
urllib.request.urlretrieve(url, dest)
logger.info("Voice presets ready.")
# ── Background model loader ─────────────────────────────────────────────────────
def _init_processor():
logger.info("Loading processor...")
from vibevoice.processor.vibevoice_streaming_processor import (
VibeVoiceStreamingProcessor,
)
return VibeVoiceStreamingProcessor.from_pretrained(MODEL_ID)
def _init_model(device: str):
logger.info("Loading model on %s...", device)
load_dtype = torch.bfloat16 if device == "cuda" else torch.float32
attn_impl = "flash_attention_2" if device == "cuda" else "sdpa"
from vibevoice.modular.modeling_vibevoice_streaming_inference import (
VibeVoiceStreamingForConditionalGenerationInference,
)
try:
model = VibeVoiceStreamingForConditionalGenerationInference.from_pretrained(
MODEL_ID,
torch_dtype=load_dtype,
device_map=device,
attn_implementation=attn_impl,
)
except Exception:
logger.warning("flash_attention_2 unavailable, falling back to sdpa")
model = VibeVoiceStreamingForConditionalGenerationInference.from_pretrained(
MODEL_ID,
torch_dtype=load_dtype,
device_map=device,
attn_implementation="sdpa",
)
model.eval()
model.set_ddpm_inference_steps(num_steps=10)
return model
def _load_voice_presets(device: str) -> dict[str, object]:
presets = {}
for name, filename in EN_VOICES.items():
path = VOICES_DIR / filename
if path.exists():
presets[name] = torch.load(
path, map_location=device, weights_only=False
)
return presets
def _load_model_sync() -> None:
global _processor, _model, _device, _model_status, _model_error, _voice_presets
with _load_lock:
if _model is not None:
return
try:
if not _is_model_cached():
_model_status = "downloading"
_download_model()
_model_status = "loading"
_download_voices()
# Resolve device from env var (set by start.sh --cpu/--cuda) or auto-detect.
_device = _resolve_device()
logger.info("Using device: %s", _device)
_processor = _init_processor()
_model = _init_model(_device)
_voice_presets = _load_voice_presets(_device)
_model_status = "online"
logger.info("Model ready on %s. Voices: %s", _device, list(_voice_presets.keys()))
except Exception as exc:
_model_status = "error"
_model_error = "Internal server error during model initialization."
logger.exception("Failed to initialise model: %s", exc)
# ── FastAPI app ─────────────────────────────────────────────────────────────────
@asynccontextmanager
async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
thread = threading.Thread(target=_load_model_sync, daemon=True, name="model-loader")
thread.start()
yield
app = FastAPI(title="VibePod TTS Server", version="0.1.0", lifespan=lifespan)
# ── Schemas ─────────────────────────────────────────────────────────────────────
class GenerateRequest(BaseModel):
text: str = Field(..., min_length=1, max_length=10_000)
speaker: str = Field(default=DEFAULT_SPEAKER)
cfg_scale: float = Field(default=1.5, ge=0.5, le=4.0)
inference_steps: int = Field(default=10, ge=5, le=20)
@field_validator("text")
@classmethod
def text_not_blank(cls, v: str) -> str:
if not v.strip():
raise ValueError("text must not be blank")
return v.strip()
@field_validator("speaker")
@classmethod
def normalise_speaker(cls, v: str) -> str:
return v.lower().strip()
# ── Endpoints ───────────────────────────────────────────────────────────────────
@app.get("/health")
async def health() -> dict:
body: dict = {
"status": _model_status,
"model": MODEL_ID,
"device": _device,
"voices": list(_voice_presets.keys()),
}
if _model_status == "downloading":
body["progress"] = {"done": _dl_progress["done"], "total": _dl_progress["total"]}
if _model_error:
body["message"] = _model_error
return body
def _sync_generate(
req: GenerateRequest,
streamer: Optional[object] = None,
cancel_event: Optional[threading.Event] = None,
) -> str:
"""Blocking inference. Returns the speaker used.
Runs in a thread-pool executor — do not call from the event loop directly.
Pass an AsyncAudioStreamer to receive audio chunks in real time.
"""
if cancel_event and cancel_event.is_set():
raise RuntimeError("Generation cancelled.")
speaker = req.speaker if req.speaker in _voice_presets else DEFAULT_SPEAKER
voice_preset = copy.deepcopy(_voice_presets[speaker])
_model.set_ddpm_inference_steps(num_steps=req.inference_steps)
inputs = _processor.process_input_with_cached_prompt(
text=req.text,
cached_prompt=voice_preset,
padding=True,
return_tensors="pt",
return_attention_mask=True,
)
for k, v in inputs.items():
if torch.is_tensor(v):
inputs[k] = v.to(_device)
outputs = _model.generate(
**inputs,
max_new_tokens=None,
cfg_scale=req.cfg_scale,
tokenizer=_processor.tokenizer,
generation_config={"do_sample": False},
verbose=True,
all_prefilled_outputs=copy.deepcopy(voice_preset),
audio_streamer=streamer,
)
if not outputs.speech_outputs or outputs.speech_outputs[0] is None:
raise ValueError("Model returned no audio output.")
return speaker
def _sse(event: dict) -> str:
return f"data: {json.dumps(event)}\n\n"
@app.post("/generate")
async def generate(req: GenerateRequest, request: Request) -> StreamingResponse:
if _model_status != "online":
detail = {
"downloading": "Model is downloading — please wait.",
"loading": "Model is loading into memory — please wait.",
"error": f"Model failed to load: {_model_error or 'unknown error'}",
}.get(_model_status, "Server not ready.")
raise HTTPException(status_code=503, detail=detail)
if _generation_lock.locked():
raise HTTPException(status_code=503, detail="Server is already generating audio. Please wait.")
async def event_stream() -> AsyncGenerator[str, None]:
from vibevoice.modular.streamer import AsyncAudioStreamer
start = time.monotonic()
streamer = AsyncAudioStreamer(batch_size=1)
cancel_event = threading.Event()
async with _generation_lock:
loop = asyncio.get_event_loop()
future = loop.run_in_executor(
None, functools.partial(_sync_generate, req, streamer, cancel_event)
)
# Drain audio chunks as they arrive from the diffusion head.
# stop_signal=None is the default sentinel that ends the queue.
while True:
try:
chunk = await asyncio.wait_for(
streamer.audio_queues[0].get(), timeout=120.0
)
except asyncio.TimeoutError:
cancel_event.set()
future.cancel()
yield _sse({"type": "error", "message": "Generation timed out"})
return
if await request.is_disconnected():
cancel_event.set()
future.cancel()
logger.info("Generation client disconnected; stream cancelled.")
return
if chunk is None: # stop signal
break
pcm_b64 = base64.b64encode(
chunk.detach().cpu().float().numpy().tobytes()
).decode()
yield _sse({"type": "audio_chunk", "data": pcm_b64})
try:
speaker = await future
except asyncio.CancelledError:
logger.info("Generation cancelled.")
yield _sse({"type": "cancelled"})
return
except Exception as exc:
logger.exception("Generation failed: %s", exc)
yield _sse({"type": "error", "message": "Internal server error during generation."})
return
elapsed = round(time.monotonic() - start, 1)
logger.info("Generation complete in %.1fs", elapsed)
yield _sse({"type": "complete", "elapsed": elapsed, "speaker": speaker})
return StreamingResponse(
event_stream(),
media_type="text/event-stream",
headers={"Cache-Control": "no-cache", "X-Accel-Buffering": "no"},
)