[FFmpeg-devel] [PATCH] Read extradata Quicktime-Atom "FFVH" for ffvhuff files from libquicktime

[Baptiste Coudurier]

Hi,

Alexander Strange wrote:
> On Oct 24, 2007, at 5:34 AM, Baptiste Coudurier wrote:
>>
>> Concerning extradata, I think It is a good opportunity to use the new
>> design defined to store Xiph codecs:
>>
>> http://wiki.xiph.org/index.php/ 
>> Oggless#Example_and_Discussion_of_the_Mov_container
>>
>> "A single glbl atom shall be placed in the stsd atom in which the the
>> global header shall be stored."
> 
> The traditional way to do it is to add an atom with the codec's  
> fourcc to the stsd atom.

'avcC' for 'avc1', 'SMI ' for 'SVQ3', 'jp2h' for 'mjp2', 'esds' for
'mp4a', 'QDM2' uses another extradata atom. Well Im not sure at all this
is the traditional way for mov. AVID uses his own scheme too.

'alac' use this design, but that's the only one I know, MPEG-4/3GP are
using different names than fourcc for extradata atoms, or the generic
esds if 'mp4a' is used as fourcc.

> This is what Xiph's QT component actually does, no matter what it  
> says there.
>
> Also, Perian implicitly defines MOV formats for everything it can  
> play; for avi formats it just copies the video packets
> and puts the extradata at the end of stsd like that.
> 
> (I uploaded ogg-audio.mov and huffyuv.mov to the mplayerhq incoming)

Like Loren pointed, it would be way more generic and simple to use a
single 'glbl' atom at the end of 'stsd' and I agree with him.

If we can agree to a common recommended practice I would be very happy
to modify mov muxer to support that generic design.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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