Thanks. That looks good, but I’m not really sure what software I need.
I’ll try to simplify what I need a little better: You have a video that you made in post-production, and it’s synced to a recording of the song that you’re performing live next week. So, your first rehearsal is over and you notice your timings are ALL off! Actually…the conductor is off because, well, he/she’s human :-). So…you make your video have a built-in click track (so you know where the beats are) and you try to find a software that can manipulate the BMP and therefore change the video accordingly (speeding it up or slowing it down). All you have to do is sit there and adjust the BPM by tapping spacebar (for instance).
I hope I clarified it a little for you :-/