# Patch for /data/ymq/demucs-service/workers/separate.py
# In run_separate_full(), ensure the return dict includes:
#   "usage": {"audio_seconds": duration}

# Find the return statement in run_separate_full and add usage field.
# The function currently returns something like:
#   return {"vocals_path": ..., "accompaniment_path": ..., "duration": ...}
# 
# Add: "usage": {"audio_seconds": result.get("duration", 0)}