[Mp4-tech] [Audio]Dynamic range/ downmix signaling

[Ameet U. Kalagi]

The DRC infoormation can be added to the AAC bitstream as an AAC FILL
ELEMENT. This is defined as a part of the ISO Spec.
ISO_IEC_13818-7;1997_Cor_1;1998(E) 
(INTERNATIONAL STANDARD ISO/IEC 13818-7:1997 TECHNICAL CORRIGENDUM 1 )
Multi-channel to Stereo downmix could be signaled through the
matrix_mixdown_idx in the Program Config Element(PCE) (ISO_IEC_13818-7).
These methods should work independent of the container format.
Regards,
Ameet
-----Original Message-----
From: mp4-tech-bounces lists.mpegif.org
[mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Gabriel Bouvigne
Sent: Saturday, September 02, 2023 1:30 AM
To: mp4-tech lists.mpegif.org
Subject: [Mp4-tech] [Audio]Dynamic range/ downmix signaling
In an AAC context, I am wondering what would be the proper way to signal
dynamic range info (variable through time) and downmix info (from 
multichannel).
I have 3 cases in mind where I think that it should probably be handled 
differently:
*AAC in mpeg-4 container
*AAC over RTP
*AAC in mpeg-2 TS
In AC3, those infos are directly part of the ATSC-A52 standard. Is there
anything defined about this in mpeg-4 (or perhaps mpeg-7)?
Regards,
-- 
Gabriel Bouvigne
www.mp3-tech.org
personal page: http://gabriel.mp3-tech.org
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