fix: try changing codec

app.py

@@ -36,7 +36,7 @@ def process_video(video_path, output_path):
     fps = int(cap.get(cv2.CAP_PROP_FPS))
     total_frames = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
 
-    fourcc = cv2.VideoWriter_fourcc(*'avc1')
+    fourcc = cv2.VideoWriter_fourcc(*'mp4v')
     out = cv2.VideoWriter(output_path, fourcc, fps, (width, height))
     
     progress_text = "Processing video... Please wait."