On 11/23/2020 4:10 PM, Jan Ekström wrote:
Until now an API user with a non-libavformat MP4 or Matroska demuxer
would have had to manually filter the extradata to skip the first four
bytes when passing data to libavcodec, so that only the OBUs would
remain. Now the AV1CodecConfigurationRecord structure can be passed
to libavcodec as-is. This is lets it to be dealt with in a similar
manner to AVC or HEVC.

This is done in the following steps:
1. A nice helper by Mark is added so that it can be utilized in stead
    of ff_cbs_read from both the decoder and parser after the CBS gains
    the capability to handle AV1CodecConfigurationRecord structures.
2. Support is added to AV1 CBS for handling AV1CodecConfigurationRecord
    in a similar vein to AVC/HEVC's avcc/hvcc handling.
3. AV1 decoder and parser are switched to utilize the newly added
    helper functionality.
4. Support is added for writing out the passed AV1CodecConfigurationRecord
    in ff_isom_write_av1c, which is called from the MP4 and Matroska
    writers.
5. Finally, both MP4 and Matroska demuxers are changed to expose the
    full AV1CodecConfigurationRecord as extradata.

Jan Ekström (5):
   avcodec/cbs_av1: add support for standard MP4/Matroska extradata
   avcodec/av1{dec,parser}: move to ff_cbs_read_extradata_from_codec
   avformat/av1: add support for passing through MP4/Matroska av1c
   avformat/mov: remove special handling of av1c extradata
   avformat/matroskadec: remove special handling of av1c extradata

Mark Thompson (1):
   cbs: Add function to read extradata from an AVCodecContext

  libavcodec/av1_parser.c   |  2 +-
  libavcodec/av1dec.c       |  5 ++-
  libavcodec/cbs.c          | 77 ++++++++++++++++++++-------------------
  libavcodec/cbs.h          | 11 ++++++
  libavcodec/cbs_av1.c      | 34 +++++++++++++++++
  libavformat/av1.c         | 14 +++++++
  libavformat/matroskadec.c |  4 --
  libavformat/mov.c         | 30 +--------------
  8 files changed, 103 insertions(+), 74 deletions(-)

Patches 1 to 4 LGTM. Patches 5 and 6 should IMO wait until after a bump since they change what the demuxers export as extradata, and existing compiled software linking to for ex 4.3 should not have to deal with this change in behavior if you use a lavf from an hypothetical pre-bump 4.4 release at runtime.
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