Update src/video_utils.py

src/video_utils.py

@@ -105,7 +105,7 @@ def write_video_with_fallback(final_clip, out_path_base, fps=25):
                 audio=True,
                 ffmpeg_params=ffmpeg_params,
                 logger=None,
-                threads=1,
+                threads=os.cpu_count(),  # ✅ multi-threading activé
             )
             if os.path.exists(out) and os.path.getsize(out) > 150000:
                 return out