If you cut at I-frames, you don't need to reencode: https://en.wikipedia.org/wiki/Video_compression_picture_types#Intra-coded_(I)_frames/slices_(key_frames) ht

If you cut at I-frames, you don't need to reencode: https://en.wikipedia.org/wiki/Video_compression_picture_types#Intra-coded_(I)_frames/slices_(key_frames) https://en.wikipedia.org/wiki/Video_compression_picture_type... If you need more resolution, you can apply more tricks, recompose i-frames from the same data, etc.