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storyforge/deploy/storyforge-windows-asr-http/app.py
kris 4ff7efb61c
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feat: auto-detect language and prefer gpu for windows asr
2026-04-06 11:14:12 +08:00

134 lines
4.3 KiB
Python

from __future__ import annotations
import os
import tempfile
import time
from functools import lru_cache
from pathlib import Path
from fastapi import FastAPI, File, UploadFile
from fastapi.responses import JSONResponse
MODEL_NAME = os.getenv("WHISPER_MODEL", "base")
BEAM_SIZE = int(os.getenv("WHISPER_BEAM_SIZE", "5"))
VAD_FILTER = os.getenv("WHISPER_VAD_FILTER", "1").strip().lower() not in {"0", "false", "no"}
DOWNLOAD_ROOT = Path(os.getenv("WHISPER_DOWNLOAD_ROOT", str(Path(__file__).resolve().parent / "models-cache")))
app = FastAPI(title="storyforge-windows-asr", version="1.0.0")
def describe_language_mode() -> str:
value = (os.getenv("WHISPER_LANGUAGE", "") or "").strip()
if not value or value.lower() in {"auto", "detect"}:
return "auto"
return value
def resolve_language() -> str | None:
value = describe_language_mode()
return None if value == "auto" else value
def describe_device_mode() -> str:
value = (os.getenv("WHISPER_DEVICE", "") or "").strip().lower()
return value or "auto"
def describe_compute_mode() -> str:
value = (os.getenv("WHISPER_COMPUTE_TYPE", "") or "").strip()
return value or "auto"
def build_runtime_profiles() -> list[tuple[str, str]]:
device = describe_device_mode()
compute = describe_compute_mode()
if device != "auto":
return [(device, compute if compute != "auto" else "int8")]
if compute != "auto":
return [("cuda", compute), ("cpu", compute)]
return [("cuda", "int8_float16"), ("cpu", "int8")]
@lru_cache(maxsize=1)
def get_model():
from faster_whisper import WhisperModel
DOWNLOAD_ROOT.mkdir(parents=True, exist_ok=True)
last_error: Exception | None = None
for device, compute_type in build_runtime_profiles():
try:
model = WhisperModel(
MODEL_NAME,
device=device,
compute_type=compute_type,
download_root=str(DOWNLOAD_ROOT),
)
app.state.runtime_device = device
app.state.runtime_compute_type = compute_type
return model
except Exception as exc: # pragma: no cover - exercised on real hosts
last_error = exc
assert last_error is not None
raise last_error
@app.get("/health")
def health() -> dict[str, object]:
return {
"status": "ok",
"service": "storyforge-windows-asr",
"model_name": MODEL_NAME,
"language": describe_language_mode(),
"device": describe_device_mode(),
"compute_type": describe_compute_mode(),
"active_device": getattr(app.state, "runtime_device", ""),
"active_compute_type": getattr(app.state, "runtime_compute_type", ""),
"download_root": str(DOWNLOAD_ROOT),
"model_loaded": get_model.cache_info().currsize > 0,
}
@app.get("/")
def root() -> dict[str, str]:
return {"service": "storyforge-windows-asr", "docs": "/docs"}
@app.post("/transcribe", response_model=None)
async def transcribe(wav: UploadFile = File(...)):
started = time.perf_counter()
suffix = Path(wav.filename or "segment.wav").suffix or ".wav"
with tempfile.NamedTemporaryFile(prefix="storyforge-asr-", suffix=suffix, delete=False) as handle:
temp_path = Path(handle.name)
handle.write(await wav.read())
try:
model = get_model()
segments, info = model.transcribe(
str(temp_path),
language=resolve_language(),
beam_size=max(1, BEAM_SIZE),
vad_filter=VAD_FILTER,
)
text = "".join(segment.text for segment in segments).strip()
duration_ms = int((time.perf_counter() - started) * 1000)
return {
"text": text,
"success": bool(text),
"duration_ms": duration_ms,
"detected_language": getattr(info, "language", None),
"detected_language_probability": getattr(info, "language_probability", None),
"error_message": None if text else "empty transcription",
}
except Exception as exc:
return JSONResponse(
status_code=500,
content={
"text": "",
"success": False,
"duration_ms": int((time.perf_counter() - started) * 1000),
"error_message": str(exc),
},
)
finally:
temp_path.unlink(missing_ok=True)