How to demux audio in avi ? tried vdubmod but it failed....

...it said he wants to rewrite the header which I denied and after going to stream list and choosen demux with marked audio it starts to process but don't goes further stays at starting position. What else program to use for that ? I don't want to convert the audio (mp3 is in vbr). I just want to demux the audio and do some checks with the mp3 natively! Could someone please send me a good tool or link to that demux tool ? BTW: I searched the forum but I didn't the right for me, did I missunderstood something ?

Howabout avidemux?

I tried it and it did the job! Thanx for your hint.