[Matroska-devel] [Cellar] Depth offsets for subtitles in case of 3D MVC tracks in MKV files

Steve Lhomme via Matroska-devel matroska-devel at lists.matroska.org
Tue Jan 26 13:34:40 CET 2016

2016-01-25 15:09 GMT+01:00 Nithin Mathew Kurien <nithinmkurien at gmail.com>:
> Hi,
> Playback of 3D MVC tracks in MKV files is now possible through LAV
> splitter and madVR. I would like to request an information field in

Sounds great !

> Matroska that specifies the depth offsets for subtitles when playing
> such video files. According to the Blu-ray whitepaper
> (http://www.blu-raydisc.com/assets/Downloadablefile/BD-ROM-AV-WhitePaper_110712.pdf),
> the way it is done in 3D Blu-rays is like this. The MVC track can have
> up to 32 Offset Metadata Sequences (OFS, also called 3D offsets in
> TSMuxer). An Offset Metadata Sequence has one depth offset (in pixels,
> either in front of or behind the plane of the screen) for each video
> frame. Each subtitle and menu track has one of these 32 Offset
> Metadata Sequences assigned to it in the M2TS file. In this way, when
> a 3D Blu-ray is being played, the subtitle or menu track can be
> displayed at the proper depth in 3D space (otherwise it would cut
> through the objects in the video, disrupting the viewing experience).
> Currently, there is no means for specifying the 3D depth of subtitles
> when playing 3D MVC MKVs. I would like to request support for the
> same.

I'm not sure I understand. Is the offset per track or per frame for
the subtitle ? If it's per track it should go in the Track Info. If
not that means a mechanism to add that information for each frame.
Maybe BlockGroup could help.

> Thanks and regards,
> Nithin
> _______________________________________________
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> Cellar at ietf.org
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Steve Lhomme
Matroska association Chairman

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