[FFmpeg-devel] [PATCH] code to parse mpeg4audio extradata

Michael Niedermayer michaelni
Thu Mar 27 02:09:50 CET 2008

On Thu, Mar 27, 2008 at 12:42:56AM +0100, Baptiste Coudurier wrote:
> Hi,
> Michael Niedermayer wrote:
> > On Wed, Mar 26, 2008 at 10:14:47PM +0100, Andreas ?man wrote:
> >> Michael Niedermayer wrote:
> >>> On Wed, Mar 19, 2008 at 04:54:03PM +0100, Baptiste Coudurier wrote:
> >>>> Hi,
> >>>>
> >>>> Here is a patch that adds parsing of mpeg4audio extradata, and retrieve
> >>>> needed infos for decoders (only mp3on4 atm, but will be needed for aac),
> >>>> and will be used by mov demuxer ideally to correctly compute sample rate
> >>>> and channels.
> >>>> Also extract common mpeg4audio code from aac_parser.c.
> >>> Iam fine with this in priciple but i am unsure if the code does not maybe
> >>> rather belong to libavformat.
> >> If the AAC decoder should reuse the code i don't think it could belong
> >> in lavf.
> > 
> > Please elaborate
> > my idea was that the mp4 demuxer would use this code to extract the various
> > thing from the mp4 atoms in .mp4 and set things like sample_rate,...
> > But maybe i misunderstood something?
> > 
> Yes, the code will also be used by mp3on4 and aac decoders to fetch
> sample rate, channels, sbr info from extradata. All decoders using
> MPEG-4 audio system will do that basically.

>From what you say it sounds like this clearly belongs in the mp4 demuxer
and not in every decoder which could be stored in mp4.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have often repented speaking, but never of holding my tongue.
-- Xenocrates
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