mp3 is mp3. How do you even know it was compressed with lame 3.96 anyway?
GSpot reports on dshow decoders, where as VDub uses ACM. Still windows comes with an ACM mp3 decoder.
I seem to recall seeing posts on some slight header differences that prevent VDub(Mod) from decompressing mp3 though. You could always try something else to decompress.
Otherwise, make a simple test.
Open the AVI with VirtualDub, Stream___Stream List___Demux. If the file is a MP3 audio (sometimes there are even AC3 audio tracks, but VirtualDubMod recognizes them), save as MP3. If it is AC3, click Demux and it will be saved as AC3.
After that, transform te MP3 to what you need with HeadAC3he (the simplest to use), BeSweet, etc. etc. ...
