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

[Baptiste Coudurier]

Baptiste Coudurier wrote:
> 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.
> 

I'd like to add that generic mechanism to libavformat, Michael are you
ok with it ? I need your blessing for ffvh.

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