For a while I was trying to encode a DVD using XviD and VirtualDubMod, but when I multiplexed the separately encoded video and audio, the audio was out of sync, just a little at the beginning and worse towards the end of the movie. I thought maybe I had screwed up the framerate on the video or something, so I scrapped those files. For simplicity's sake my next attempt to encode them was using Nero Digital, which automatically took care of the audio and video at the same time, without me having to worry about anything. The resulting file was fine with no sync issues, but the audio was really quiet, so I demuxed the audio/video with mp4UI, normalized the audio, didn't touch the video, and remultiplexed (also with mp4UI). Now, it's in sync at the very beginning, but when I seek to the end it's horribly out of sync. Any ideas why I keep having sync issues or possible ways to fix them?