I usually edit in Vegas 3 with DV from my camcorder. I recently tried editing MPEG-1 from my TV Tuner app, and when I then render to MPEG-1 at a lower bitrate, the audio is a couple of seconds out of sync.
I have never had a sync problem with DV rendered to MPEG-2.
Thanks for the reply. Dropped frames are a possibility, I guess, but I rendered it in TMPGEnc and it was fine. I think it might have been because I edited it in the trimmer in Vegas, but I'll have to check...I forget now.