Subject: [Cellar] AV1 update

From: Steve Lhomme <[email-masked]>
Date: Thu, 16 Aug 2018 14:54:16 +0200

As the work on the ISOBMFF produced many welcome changes I updated the
current draft for Matroska.

The main changes include:
- use the structure from AV1CodecConfigurationRecordv1 in CodecPrivate
so we can identify the codec variant precisely before starting
playback.

- not include any OBU anymore in the CodecPrivate. They are already
found in the Blocks and the data that would have been useful are
already in the CodecPrivate structure or the metadata in the Matroska
fields.

- separate the mandatory TrackEntry elements from the others and
separate the ones which value come from the Sequence Header OBU, the
metadata OBUs or other fields.

- add the notion of CVS Sequence Header OBU which corresponds to all a
Sequence Header OBU where all the bits are equal for the whole
duration of the Coded Video Sequence.

Seeking is now straightforward to Keyframes/BlockGroup with no ref.
The rest remains undefined territory. But we don't omit and reinject
any OBU.

As always the current draft can be found here:
https://github.com/Matroska-Org/matroska-specification/blob/av1-mappin/codec/av1.md

-- 
Steve Lhomme
Matroska association Chairman