Fix HF build deps + Linux null sink

Dockerfile

@@ -1,21 +1,26 @@
 FROM python:3.11-slim
 
-# System deps (ffmpeg for audio conversion + git for some pip installs if needed)
+# System deps:
+# - ffmpeg: audio conversion
+# - libsndfile1: required by soundfile/librosa
+# - build-essential/pkg-config: needed for some wheels/extensions (e.g., webrtcvad if it compiles)
+# - git: in case any pip install pulls from git
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
     git \
+    libsndfile1 \
+    build-essential \
+    pkg-config \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
 
-# Install Python deps
+# Faster / more reliable installs
 COPY requirements.txt /app/requirements.txt
-RUN pip install --no-cache-dir -r requirements.txt
+RUN pip install --no-cache-dir --upgrade pip setuptools wheel \
+    && pip install --no-cache-dir -r requirements.txt
 
-# Copy the application code
 COPY . /app
 
-# Hugging Face Spaces expects port 7860
 EXPOSE 7860
-
 CMD ["uvicorn", "app:app", "--host", "0.0.0.0", "--port", "7860"]

app.py

@@ -2,6 +2,7 @@ import os
 import re
 import shutil
 import subprocess
+NULL_SINK = "NUL" if os.name == "nt" else "/dev/null"
 from fastapi import FastAPI, UploadFile, File
 from fastapi.responses import JSONResponse
 
@@ -28,7 +29,7 @@ def detect_trim_times(wav_path: str):
     """
     # Run silencedetect and capture output
     p = subprocess.run(
-        ["ffmpeg", "-i", wav_path, "-af", "silencedetect=noise=-35dB:d=0.35", "-f", "null", "NUL"],
+        ["ffmpeg", "-i", wav_path, "-af", "silencedetect=noise=-35dB:d=0.35", "-f", "null", NULL_SINK],
         cwd=WORKDIR,
         stdout=subprocess.PIPE,
         stderr=subprocess.STDOUT,