logging

main.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import asyncio
 import contextlib
+import logging
 import os
 import shutil
 import tempfile
@@ -13,6 +14,9 @@ from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import FileResponse
 from starlette.background import BackgroundTask
 
+logger = logging.getLogger("ffmpeg-api")
+logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(name)s: %(message)s")
+
 
 FFMPEG_BINARY = os.getenv("FFMPEG_BINARY", "ffmpeg")
 ALLOWED_CODECS = {"libx264", "h264_nvenc"}
@@ -119,6 +123,9 @@ async def run_ffmpeg_command(command: list[str], error_prefix: str) -> None:
 
     if process.returncode != 0:
         error_message = (stderr or stdout).decode("utf-8", errors="replace").strip()
+        logger.error(
+            "%s (ffmpeg rc=%s): %s", error_prefix, process.returncode, error_message or "unknown error"
+        )
         raise HTTPException(
             status_code=500,
             detail=f"{error_prefix}: {error_message or 'unknown error'}",
@@ -219,10 +226,12 @@ async def run_ffmpeg_compose(
         "error",
     ]
 
+    if codec == "h264_nvenc":
+        command.extend(["-init_hw_device", "cuda:0"])
+
     if kind == "image":
-        command.extend(["-loop", "1"])
+        command.extend(["-framerate", str(fps), "-loop", "1"])
     elif codec == "h264_nvenc":
-        # Keep CPU filters, but still ask FFmpeg to prefer CUDA decoding for video backgrounds.
         command.extend(["-hwaccel", "cuda"])
 
     command.extend(