[Ffmpeg-devel] Native ogg demuxer

[matthieu castet]

Hi M?ns,

M?ns Rullg?rd wrote:
> matthieu castet <castet.matthieu at free.fr> writes:
> 
> 
>>What's the point of doing external sub-plugin that use global
>>variable instead of static variable and if conditions ?
> 
> 
> Cleaner design, IMHO.
> 
Yes but you could have all the sub-plugin in the same file and make it
static. This is more or less what do liboggz

> 
>>Also now the parsing of the extrada (comments, codec init, ...) is
>>done twice : once in the demuxer, once in the decoder.
> 
> 
> The codec does not, and should not, touch the comment section.
> 
Actually if you look theora implementation it read and skip and the comment.
So you sugest to not put the comment in the codec extradata (2nd header
in vorbis and theora) ?



> 
>>There are usefull only if you want remuxer ogg in another format. But
>>actualy there no standart way to store the extradata in other muxer (I
>>know only vorbis in ogg in avi, and there still the ogg layer), and
>>these informations could be still overwritten by the decoder.
> 
> 
> There are lots of matroska files with vorbis audio, and I've heard
> mention of storing vorbis in nut.
> 
So what's the standard way of storing vorbis extradata in matroska ?

Actualy in ffmpeg (so in nut) the extradata is
u16 size of the 1st page
1st page
u16 size of the 2nd page
2nd page
u16 size of the 3rd page
3rd page

cheers,
Matthieu