In summary, my problem is that the AVI file I read into Avitricks (version 1.65) has its audio and video in sync, but the output file written by Avitricks gets gradually out of sync - it starts out OK, but gradually the audio gets slightly ahead of the video, and is a second or two ahead of the video by the end.

I have recorded a movie from TV on to my DVD recorder's hard disk, edited out the ads on the DVD recorder, and then burnt it to a DVD, producing VOB files. Now I want to do some more editing on my PC - Australian TV stations have an irritating habit of talking over the credits to advertise upcoming shows etc, and in this case they talked over a song playing during the credits. I have a copy of the song on CD, and have ripped it to a WAV file. I then used Avitricks to add the extra WAV file at the right place in the movie, and adjusted the volume level of both the original sound track and the WAV file to fade them in and out at the right places. However when I save in AVitricks, the output file gets out of sync as mentioned above. However I think the WAV file is starting at the right time, because in the output file the sound from the 2 sources now doesn't line up properly.

To convert from VOB to AVI (to read into Avitricks), I'm using a program from the cover DVD of an Australian PC magazine, which is a GUI front end for the FFmpeg command line encoder. It uses mpeg4 video codec and mp3 audio codec (-vcodec mpeg4 -vtag DX50 -acodec libmp3lame, among other options, in the generated FFmpeg command). That AVI file plays fine in Windows Media player and Winamp, with no sync problems. In the Avitricks output AVI file, for the video and audio codecs, I have tried Xvid and PCM, DivX and PCM, and DivX and MP3, but they all get out of sync (I have installed the DivX and Xvid codecs from www.divxmovies.com/codec and www.xvidmovies.com/codec).