Yea, mp3 and mp2 both work–confirm.
Demux of the AAC track from a MP4v seems to have a bug, either that or I am botching it bigtime.
The file created by Avidemux using the procedure you outlined above appears to be the right size, but no program I have can recognize it as a legitimate audio file(tried VLC, MPC, foobar2000, & Winamp)
I also tried GSpot and MediaInfo, both give zilch info on the created file. I also tried changing the file extension: .aac, .mp4,. m4a—the file just isn’t recognized as audio by the software I have.
Extracting the AAC track from the same MP4v using YAMB or RipBot264 are recognized and played by all the above software. (and extraction is fast)
Sorry if the above is all OT–YAMB & RipBot264 both extract AAC from mp4v without re-encoding if the mp4v contains an aac track. I am sure there is a lot of other software out there that can do this as well.