I can't get video to stay in sync with audio for more than about 1:30 - after that it begins to drift. This is a huge complaint with clients. Quicktime Pro seems to have a much bigger problem than, say Cleaner, but the only time I have not had a problem is with Windows Media. Cleaner (at least my version) doesn't appear to offer H.264, which seems to offer the best trade-offs between file size and quality. I know I have seen Quicktimes with audio that would hold sync over 30 minutes, but I haven't had much luck producing one. I'm on a PC, so I'm not sure if that is an issue, but one would think Quicktime Pro would work the same on both platforms.
Image Design Productions, Inc.
I've never had anything go out of sync exported out of QT Pro in over a decade, but I have with cleaner, years ago. Cleaner hasn't been update usefully in years and I wouldn't recommend it to anyone anymore. QT Pro is a very niceplayer with export features but I wouldn't use it for serious transcoding/compression work. Have a look at Procoder from Grass Valley. is you want a high quality, professional and regularly updated application: http://www.canopus.com/products/ProCoderSW/index.php