[Matroska-devel] [Fwd: Re: Dirac mapping for Matroska]

[Sebastian Dröge]

Ok, after talking to one of the Dirac developers I'd like to change the
previous proposal completely ;)

The plan would now be:
- CodecID is "V_DIRAC"
- No CodecPrivate, no changing of the stream
- A Matroska block/lace contains all Dirac packets up to and
  including a picture. This means, all padding, maybe a sequence
  header and maybe auxiliary data and then the picture for which
  all this previous data was. This makes demuxing much easier
  and prevents broken streams created by a muxer or demuxer.
- A block is a keyframe whenever it contains a sequence header.
  Sequence headers are added to the stream by the encoder at
  places that are meant as "seek points" and on which decoding
  could start. There's no easy way of detecting whether a picture
  can be decoded on it's own in any other way.

The Track elements can contain the video width/depth, aspect ratio,
framerate etc but that's not required. Also setting the ReferenceBlock
element is not necessary.

What do you think? This is rather easy to implement, allows all
flexibility and makes sure that the Dirac streams are not damaged ;)