[Matroska-devel] Dirac mapping for Matroska

[Михаил Мацнев]

David Schleef wrote:
> Now that Schroedinger-1.0.0 is out, I'm working on integrating Dirac
> support into other projects.  I'd like to get a specification nailed
> down (and a link on the Dirac website) on how to embed a Dirac stream
> into Matroska.
> 
> Dirac is a self-contained stream containing variable sized packets
> containing either pictures or sequence headers.  "Self-contained"
> meaning that there is no out-of-band codec data.  Decoding can be
> started at any sequence header (e.g., after seeking), and sequence
> headers are encoded periodically by the encoder.  Dirac streams are
> constant framerate.
> 
> I implemented the obvious "V_DIRAC" mapping in GStreamer's matroskamux
> and matroskademux elements using V_MPEG2 as an example.  It appears to
> work fine, but, uh, that means very little.
> 
> Example of Dirac in Matroska at:
> http://www.schleef.org/~ds/dirac_example.mkv
Does the current dirac encoder generate presentation timestamps? This is
important to get right, especially if the coding order is different from
presentation order, because streams are not limited to constant frame rate
in Matroska.