Problems Demuxing AAC Audio from mp4 files

[flop71]

Hi all,

I'm trying to demux the AAC audio from a bunch of files but am having some problems:

1) If i use Yamb it will demux to an aac file which looks ok (ie correct file size but unplayable)

2) if i use avidemux i can demux about 5 mins of audio to a wav file, which again is unplayable.

The Audio plays file from the mp4 file so am not sure what the problem is. Any ideas

Thanks
Flop

[nm]

1) If i use Yamb it will demux to an aac file which looks ok (ie correct file size but unplayable)
Yamb probably outputs a headerless AAC stream. You could use faad to add an ADTS header: faad -a out.aac in.aac

[Sharktooth]

what player you use?

[flop71]

Ok so after a bit more digging i found a tool mencoder which will do the trick, there are also some neat batch files:

http://www.techlifeweb.com/2007/04/how-to-convert-ipod-video-to-divx-or.html

I just converted an mp4 file to avi (DX50, Mp3 lame) and it works a treat no Audio lag and quality is indstinguishable from the original.

Thanks for the replies.

Flop

[Kurtnoise]

Yamb probably outputs a headerless AAC stream.
certainly not...MP4Box puts always an ADTS header for aac streams extraction.