[Live-devel] recorded files atoms errors
finlayson at live.com
Tue Nov 16 01:29:59 PST 2004
>I've done some more research why the recorded files won't play/get info on
>some of the tools I use.
>* all of the test files I made have broken mp4a atoms (MPEG-4 AAC sample
>description) or ESDescriptors.
>* they all specify an empty IOD which means "empty MPEG-4 presentation"
>(eg you see nothing).
>* In some files the mp4a.esds.ESDescriptor is broken: SLConfig is included
>in ESD.decoderConfig when it must be in ESD. And the ESDescriptor size is
>* In some other file the entire mp4a atom is corrupted (junk data before
>the esds atom)
Thanks for looking into this.
Can you point me at the document(s) that describe *specifically* what the
"mp4a", "esds" and "iods" atoms should contain - for MPEG-4 audio
content? When I wrote the "QuickTimeFileSink" class (that generates ".mov"
and ".mp4" format files), I looked at the MPEG-4 Audio, Systems, and File
Specification documents, but none of these were very clear about what these
atoms should contain. So I ended up reverse engineering some existing
files. Fortunately, I was able to come up with code that generates files
that plays correctly[*] on QuickTime Player and RealPlayer 10, but
apparently (as you found), not on some other players.
So, it would be nice to be able to do this properly.
[*] Except for the MPEG-4 audio track duration problem. However, this has
now been fixed, and will be included in the next software release. Stay
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