Problems extracting audio with virtualdub

[Skillian]

Before I get shot down for this I have searched the forums extensively for this and found some similar and relevant problems. However I haven't found a real solution. I could be wrong and if someone has answered this already i'm sorry but I couldn't find it.

I encode DivX avi's to SVCD using the guide on this site so the first step is to extract an uncompressed .wav file using virtualdub. I have done this many times (including files with variable bit rates) but when trying to convert part 1 (and part 2) of the harry potter 2 disc divx file I get a .wav file that is 1 hr 11 mins 23 secs long, even though the actual divx video is 1 hr 11 mins 30 secs long.

This obviously means I get a gradual lead in the audio synch when converting to mpeg. The audio in the divx file is VBR and not AC3, and I'm sure I've done files like this before. I've also tried extracting a .wav file with other programs (goldwave, cool edit 2.0, avi2wav) and the .wav always comes out 7 seconds shorter than it could be.

Anyone know what the problem is, or know how to fix it? Any help would be greatly appreciated.

[p_l]

Might it be that the audio is VBR? If so, try the Vdub MP3 method in King John's Guide to Bad Frames.

Hope it helps!