[Ffmpeg-devel] Re: Re: Re: [theora-dev] Theora encoding in FFmpeg

Diego Biurrun diego
Mon Jan 1 12:47:52 CET 2007


On Sun, Dec 31, 2006 at 09:17:52PM +0100, Michael Niedermayer wrote:
> 
> On Sun, Dec 31, 2006 at 08:09:54PM +0000, Paul Richards wrote:
> > On 31/12/06, Michael Niedermayer <michaelni at gmx.at> wrote:
> > >On Sun, Dec 31, 2006 at 05:56:11PM +0000, Paul Richards wrote:
> > >> And on a deeper level..
> > >>
> > >> Why is all this special packing of the output from theora_encode_***()
> > >> into the extradata required?  I naively assumed that any packing like
> > >> this would be the responsibility of the muxer...
> > >
> > >no of course not, just think about this for a moment, should the avi muxer
> > >contain code to repackage theora, vorbis, ... headers? then what about
> > >matroska, nut, asf, mov, mp4, ... ? should every muxer contain (duplicated)
> > >code to pack all the codec specific xiph headers into a single packet?
> > >
> > >and then after you duplicated that code in every muxer, you will have to
> > >add code to every corresponding demuxer to undo it otherwise you cannot
> > >copy a stream between 2 containers witout reencoding ...
> > >
> > >simply putting the (de)packaging code into the 2 or 3 xiph codecs is much
> > >easier ...
> > >
> > 
> > In that case shouldn't there be a function in libtheora to concatenate
> > all of the "extradata" packets together in a container-insensitive
> > way?
> 
> yes, and this container-insensitive way should be documented in the 
> theora/vorbis/... spec
> iam sure many people would be happy if this would happen ...

If you guys don't keep the xiph lists in the CC, they will never read
this, though ...

Diego





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