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

Hendrik Leppkes via Matroska-devel matroska-devel at lists.matroska.org
Mon Feb 29 09:22:41 CET 2016

On Mon, Feb 29, 2016 at 8:51 AM, Steve Lhomme <slhomme at matroska.org> wrote:
> If we want the general case to work we may introduce an element at the
> same level as CodecState that defines the Z-order for the Block. That
> means it would have to translate the lookup index in the SEI to the
> actual z-order value (if I understand correctly how it works). We need
> to define if it's like the CodecState, ie it only changes from scene
> to scene, not Block by Block. So it would be a State that needs to be
> remembered when needed and only written when it changes.
> What is the range of depth allowed in Blu-Rays ? Are they discrete
> value or floating values ?

The "depth" is defined in discrete pixel values in the BD SEI, ie. the
offset to move it left/right for each eye, so it doesn't have a direct
meaning of "depth", but just instructions on how to render it.
Note that the way this is implemented on Blu-rays, the depth can
change from frame to frame. Every GOP has a new SEI block which
includes one offset for every frame in the SEI, so its controlled on a
frame level, not a scene/GOP level.

(( This time sent to the list as well. ))

- Hendrik

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