Encoded file gets 50ms/s out of sync.

Hi all.

I'm just about to rip all my DVD's containing musicvideos for use in my Car-PC.
I just have a really annoying problem...
I'm using latest version of Dr. Divx to convert my vob files to Divx.
No matter what I do the file starts in sync, but when playing it gets smoothly out of sync. In the end of a musicvideo the sound is like 0,1sec out of sync. It seems that some frames from the movie-part is "cleared" meaning that the video plays a little faster than the audio, so it gets more and more out of sync.

I have ripped the DVD with DVD shink to single files for each video.

Anyone having suggestions?

Thanks...