[Matroska-devel] LibMatroska example question

Mike Matsnev mike at po.cs.msu.su
Thu Jan 26 15:13:12 CET 2006


On Thu, Jan 26, 2006 at 02:02:43PM +0100, Armin M?ller wrote:
> I downloaded and tried the simple matroska muxer from the x264  
> project. It looks very promising, and i can read the code and I think  
> I understand what it is doing.
> 
> When calling
> 
> int  mk_writeHeader( mk_Writer *w, const char *writingApp,
>                      const char *codecID,
>                      const void *codecPrivate, unsigned  
> codecPrivateSize,
>                      int64_t default_frame_duration,
>                      int64_t timescale,
>                      unsigned width, unsigned height,
>                      unsigned d_width, unsigned d_height );
> 
> I don't know what codecPrivate should look like.
> 
> The usage of matroska in x264 shows how to use it, but there are two  
> variables
> 
> uint8_t   *sps, *pps;
> 
> and I don't know what they stand for and what values they contain.
> 
> I hope I am not a nuisance to the list for such basic matroska  
> questions.
Many video codecs require some initialization data that is stored
separately from video frames. For mpeg codecs it's a sequence
header/VOL/sequence parameter set/etc, for others it's some opaque
data with unpublished format that is provided by encoder and required by
decoder. More details at http://haali.cs.msu.ru/mkv/codecs.pdf




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