[vlc-devel] [PATCH] demux: mkv: fix more hvcC detection

[Zhao Zhili]

> On Jun 11, 2018, at 11:06 PM, Steve Lhomme <robux4 at ycbcr.xyz> wrote:
> 
> Can't speak for mkvmerge but DivX had their own player so I guess they could do it.
> 
> 
> On 2018-06-11 4:44 PM, Francois Cartegnie wrote:
>> Le 11/06/2018 à 16:40, Steve Lhomme a écrit :
>>> Seems alright but I don't know much about HEVC so I can't tell if the
>>> detection is better or worse.
>>> 
>> The right question is how come a version producing a broken DCR can be
>> released in the wild, with no possible decoding, so totally untested.
>> 
> 
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They did it before 14496-15 third edition release. Some information:
https://lists.matroska.org/pipermail/matroska-devel/2013-September/004567.html
---------------------------------------

Contents of CodecPrivate:

Generally follows the definition of HEVCDecoderConfigurationRecord in
ISO/IEC 14496-15, but until the 3rd edition of 14496-15 gets
officially finalized, the version entry (configurationVersion) shall
be written as 0 (zero), not 1 (one) as 14496-15 defines it.

After the official release of 14496-15, 3rd ed., the extradata format
can be checked and possibly updated, and the configurationVersion can
finally be bumped to to match the 14496-15 specification.
----------------------------------------

And
https://github.com/jaya-divx/mkvtoolnix/blob/master/src/common/hevc.cpp#L230
----------------------

/* Codec Private Data
The format of the MKV CodecPrivate element for HEVC has been aligned with MP4 and GPAC/MP4Box.
The definition of MP4 for HEVC has not been finalized. The version of MP4Box appears to be
aligned with the latest version of the HEVC standard. The configuration_version field should be
kept 0 until CodecPrivate for HEVC have been finalized. Thereafter it shall have the required value of 1.
---------------------