Quite simply, I've got a number of MP4 files encoded via Handbrake into a nice high-quality but compact H.264 format, however there are some parts I'd like to trim. In the past I've used MPEG StreamClip, but it doesn't cope with these files at all, either corrupting the start of trimmed clips or not trimming to exactly my selection. I get the impression it's trying to trim the nearest keyframe, rather than creating a new one, but I can't really cut it any other way. Anyway, I'm wondering what other tools there are out there that can let me just to trim a .mp4 file, ideally without any lengthy re-encoding steps, as I'm happy with the current encoding, I just want to split the file. Ideally I'm looking for something free, command line is fine, or at least fairly cheap, as I'm not doing this professionally or anything.