[Matroska-devel] S_DVBSUB

Steve Lhomme slhomme at matroska.org
Sat Feb 26 10:34:32 CET 2011

On Sat, Feb 26, 2011 at 10:32 AM, Dan Haddix <dan6992 at hotmail.com> wrote:
> OK I think we have a plan. I'm going to lay it out one more time just for
> posterity...
> If a DVB subtitle stream contains more then one substream then the muxer
> must separate each substream into individual MKV tracks. This can be done by
> either... a) creating a copy of each segment who's page ID corresponds to
> either the composition or the ancillary ID of the substream to that track or
> b) using the TrackOperation tag to create a virtual track which
> automatically combines segments from two other tracks which contain the
> ancillary data and the composition data respectively.
> In addition each MKV track will contain 8 bytes of CodecPrivate data which
> will contain the following information...
> ISO_639_language_code - 24 bits
> subtitling_type                - 8 bits
> composition_page_id      - 16 bits
> ancillary_page_id           - 16 bits
> No default values are assumed for these variables so if the CodecPrivate
> data is missing, or malformed, then the track will be treated as invalid and
> rejected by the player/demuxer.
> If that sounds right then I will add support to VRD for the next release. I
> can also help add playback support to VLC. Although I can't currently build
> VLC so someone else will need to build the changes and test them out. Any
> volunteers?

Not for now. I have plenty of things to do on VLC but I lack the time.
What platform are you building VLC on ? On windows it turns out it's
easier to use a Linux Virtual Machine to cross-build it, and then use
the package on windows (via local network sharing).

> Now that we're done with this do we want to discuss how best to store
> 608/708 captions and Teletext? :)

Good luck ;)

Steve Lhomme
Matroska association Chairman

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