[Matroska-devel] multiple video streams stereo 3D mode broken

Ben Humpert ben at an3k.de
Wed Jun 6 17:51:03 CEST 2012

In reply to this post:

2011/2/27 Steve Lhomme <slhomme at matroska.org>:
> Parsers that don't know about TrackOperation will not be able to play
> these tracks. That's one of the reason for the bump to Matroska v3. A
> file marked as readable by v3 (and up) compliant readers and can only
> handle v2 may decide not to play the file. The left and right tracks
> may be marked as NOT Enabled as well (0xB9) and then the player ens up
> with just the virtual track that it can't play anyway.

Does that mean that a mk3d using frame sequential with two separate
video tracks cannot be played back in 2D on mkv v2 systems? If so this
is a huge downside of matroska since the Bluray specification is able
to do that.

Isn't it possible to add a fallback somehow like "if you can't read
the end result (virtual track/trackoptions) fall back and simply read
the first video track (specified by the virtual track)".

If v2 can't read 3D virtual tracks at all v2 should just read the
first video track in the container instead of the unreadable 3D
virtual track -> Since Frame Sequential always serves the left eye
first the video track for the left eye should always be the first
video track in the container.
If creators want to play a trailer, fbi warning or whatever in front
of the main 3D video they only have to make sure that the left eye
video track is the first video track. Regardless where the trailer
video tracks are placed in the container, the creators always have to
use a virtual timeline to get first the trailers and the the main
video played back, so this should not be a problem.
For sure v2 has to ignore the "enabled/not enabled" setting for the
first video track if the fallback is used!

This may not add 3D fallback support to all players but to all
frequently updated ones (eg. jailbreaked appletv).

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