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

[Baptiste Coudurier]

Hi,

Michael Niedermayer wrote:
> 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.
> 

Huh, I don't understand.
How are decoders supposed to parse extradata, AAC GASpecificConfig for
example ? Duplicate the code ?

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