[Libav-user] Remuxing from AAC to MP4, bitstream filtering and corrupted AAC Config

[Stefano Sabatini]

Hi all,

posting here in case someone can provide ideas.

With the attached code I'm able to stream-copy and remux an AAC file
to an MP4.

$ remuxing in.AAC out.mp4

$ mp4info version 2.0.0
out.mp4:
FindBytesProperty: no such property moov.trak[0].mdia.minf.stbl.stsd.*[0].*.esds.decConfigDescr.decSpecificInfo[0].info (src/mp4file.cpp,865)
Track	Type	Info
1	audio	MPEG-4 Unknown Profile(0), 38.150 secs, 149 kbps, 44100 Hz
 Encoded with: Lavf55.10.101

$ MP4Box -info out.mp4 
* Movie Info *
	Timescale 1000 - Duration 00:00:38.151
	1 track(s)
	Fragmented File: no
	File Brand isom - version 512
	Created: UNKNOWN DATE
File has no MPEG4 IOD/OD

iTunes Info:
	Encoder Software: Lavf55.10.101

Track # 1 Info - TrackID 1 - TimeScale 44100 - Media Duration 00:00:38.150
Track has 1 edit lists: track duration is 00:00:38.151
Media Info: Language "Undetermined" - Type "soun:mp4a" - 1643 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
Corrupted AAC Config
Self-synchronized
Alternate Group ID 1

...

If I convert the file with the command:
$ ffmpeg -i in.aac -c copy -bsf:a aac_adtstoasc -y out2.mp4

$ mp4info out2.mp4 
mp4info version 2.0.0
out2.mp4:
Track	Type	Info
1	audio	MPEG-4 AAC LC, 38.150 secs, 149 kbps, 44100 Hz
 Encoded with: Lavf55.10.101

$ MP4Box -info out2.mp4
* Movie Info *
	Timescale 1000 - Duration 00:00:38.151
	1 track(s)
	Fragmented File: no
	File Brand isom - version 512
	Created: UNKNOWN DATE
File has no MPEG4 IOD/OD

iTunes Info:
	Encoder Software: Lavf55.10.101

Track # 1 Info - TrackID 1 - TimeScale 44100 - Media Duration 00:00:38.150
Track has 1 edit lists: track duration is 00:00:38.151
Media Info: Language "Undetermined" - Type "soun:mp4a" - 1643 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 44100
Self-synchronized
Alternate Group ID 1

...

So the problem seems related to the missing profile information.

Help with the issue is very welcome. I plan to send the example for
inclusion once I spot the problem.
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