I spent a couple days working on converting a couple of avi files to burn to dvd where the audio and video were out of sync. They looked fine when viewing as avi on the PC, but were off when converted to DVD. I read a lot of threads on this and other websites and tried over 10 video converter programs before I stumbled onto the easiest method that worked for me.
I am a newbie at this and doing things like demuxing the audio and video streams into separate files with advanced software was really beyond me, but I did try (and did learn a lot in the process - more than I wanted to know!). I thought I had found a good method by reading this or that thread but when I would try something would always go wrong - I did not have the correct codec for this or that program or the software said there was a problem with the AVI and could not process the file. I guess part of my problem is I don't know how to integrate the various programs with the codecs I have installed (ACE Mega Codec pack and a few others). I figured this would be an automatic process but I guess that is not correct. It was very frustrating.
This is the easiest method I found. Use NeroVision Express 3 to create VOB files by transcoding to hard disk (not burning to DVD yet). This will typically create 4 or 5 VOB files per movie. Be sure to specify or note the directory to save it to so you can find the VOB files afterwards. After this is complete, use VideoReDo Plus ( http://www.videoredo.com/ ) . Open one of the VOB files in VideoReDo and it will start to play. Select Tool->Adjust Audio Syncronization and it provides a slider bar window that allows on-the-fly adjustment of the audio sync. All of mine that were out of sync required between + 320 to 330 msec adjustment to correct. After this is done, hit the "Save As" button and choose VOB output file format. It will re-mux the file, but it is a short process - less than 2 minutes. Each VOB must be edited separately. Be sure to save them with a sequential filename (create a new directory and save them to VOB01, VOB02, etc, for example.) Once all the VOBs are edited to adjust the sync, drag them to the Nero burn window. Burning VOBs does not take that long since the files are already transcoded.
VideoReDo was the only program I found that allowed this easy, interactive adjustment of audio sync suitable for dummies like myself.