When I word with individual clips, they are synchronized to the music, and even if I select a large group of clips they're okay.
But if I play the whole video through, the whole thing falls apart. The video plays faster than the audio, so by the end of the 1.5 minutes I have completed, the video is short by about a second. It doesn't seem to be an even loss, either--some clips seem to take fa shorter than they ought to, while other (even some after the short clips) are right on the beat.
The quicktime reference movie for the video also plays at the screwed-up rate. Most of my clips were from the same source file, too--DVs at 29.97 fps, made with the same convertor and clip-cutting software.
Any ideas what's wrng and how to fix it? (Besides sticking in extraneous footage? That's my only workaround so far, and it makes it difficult to plan the film.)

