Chopping up video

[robfoster]

Just for fun ive recorded myself making drum noises into my webcam as a quicktime movie, now i want to call that into ableton and create a video beatbox, by slicing up the sounds, and having the video run in sync with the sliced up beats, ive managed it once, but i dont know how i made it work, every video i put in after the first one i did is about half a second out of sync, the first video is in perfect sync still, has anyone got any ideas how to get it in sync, ps Tom Cosm does this on his website, its really good fun when it works.