[NUT-devel] Re: [Vorbis-dev] minor Vorbis specification amendment proposal

[Baptiste Coudurier]

Hi

Alex Beregszaszi wrote:
>>> [...]
>>>
>>>    Quicktime lacks an unambigous place for a global header so its
>>>    outside the scope of this document.
>> we could add mov to the list of supported containers if we define a
>> chunk for the global header, other codecs have their own codec
>> specific global header chunks too, maybe "glbl" could be used if its
>> not taken yet, but i need to look more carefully at the mov/qt spec so
>> we unambiguosly define and place it
> 
> glbl below trak? vmhd/mdhd/smhd/tkhd are leaf

Humm, IMHO best place is in stsd like every other codec. Decoder
specific config atom like 'dvrb'. Is MOV fourcc for vorbis defined ?
I can't find it anywhere. 'vrbs' would be nice.

> Will some Quicktime fanatic speak up? Mike?
> 
>> about .mp4, that wasnt covered by the quicktime/mov point, it has a
>> ESDS atom into which a global header can be put, but iam not very
>> familiar with the mpeg4-systems / iso-mp4 container specs so i didnt
>> mention it
> 
> That ESDS looks HUGE.
> 

MP4 specs would require it to be in stsd as 'mp4a' and object type set
correctly in esds. It seems gpac already does it and uses a object type.
That object type should be registered to mp4ra.org I think.

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