I am having trouble converting avi files to Apple TV format using Quicktime Pro. I have a number of TV shows running approx. 45 minutes and about 350MB in size. They play perfectly in Quicktime as avi files but when I export them to Apple TV format, the audio goes out of sync. Strangely, the first 35 minutes or so are fine: then the audio suddenly drops 3 or 4 seconds off. I have never had this conversion problem before. I've tried a number of different files with the same unsatisfactory result. Any thoughts on a solution?