Videos ignoring the start frame at preprocessing

[davidlainesv]

The preprocessing.py file does not take in account the start frame when the video ends at the last frame of the video.

if end_frame <= 0: shutil.copyfile(src_video_path, dst_video_path) continue

I have found around 6 videos that ends at the last frame of the video but start after the first frame of the video (start_frame != 1) and the code copies the video to the destination folder as it is without slicing the video accordingly.