Is there any program that can be used to cut out parts of a video file without re-encoding.

The way I'm thinking is if you already have a video file, you should be able to just copy the data from 1 file to another like a file splitter.

Video encoding don't encode frames in isolation, frames are usually encoded based on the previous frames (basically compress a motion compensated frame diff) or as chunks of frames, you can't really cut an encoded video without screwing up the parts near the cut, depending on the algorithm it might be possible to only re-encode parts of the video but you can never really avoid it entierly (there might be old formats that compress individual frames but they would be horribly inefficient)

@ItsNotMyFault but then how does web streaming and seeking work? I can jump to any sort and it plays just fine?

@billgates@billgates keyframes usually, so it only have to redecode a few seconds (everything between the point you jumped to and the previous keyframe) when you jump, this is why jumping in a stream can be fairly slow. (And also why live digital broadcasts tend to become garbled for a few seconds if there is a temporary connection issue).