ensure vod does not exist

hls_download.py

@@ -8,6 +8,10 @@ def download_clips(stream_url, out_dir, start_time, end_time, resize=True, use_6
             if f.endswith('.mp4'):
                 os.remove(os.path.join(out_dir, f))
     output_file = os.path.join(out_dir, f"train_{len(os.listdir(out_dir))}.mp4")
+    try:
+        os.remove(output_file)
+    except FileNotFoundError:
+        pass
     if resize:  # resize and convert to 30 fps
         ffmpeg_cmd = [
                 'ffmpeg',