No matter what, out of sync

[Dunnyman]

Virtually every file that's avi (XVID, DIVX, etc) when converted to ANY MPEG format (VCD, DVD, SVCD, etc) comes up with sync issues on the sound, and I'm getting terribly frustrated with it. I can take an MPEG1 file, and go to DVD spec with it, and it's perfect, every time, but if my source is an AVI of any kind, twelve hours of encoding for the sound to be off by three or four seconds.
Why is this???
I tried going to MP2 instead of AC3 on DVD, same problem, is there anything I can do to get a watchable encode?

[major]

Email me a sample process output for your outsynced encoding to major4@mac.com together with your settings and the list of plugins you have in /Library/Quicktime.