[FFmpeg-trac] #9713(avcodec:new): Hardware accelerated decoding fails on M1 macs for certain videos encoded with h264

[FFmpeg]

#9713: Hardware accelerated decoding fails on M1 macs for  certain videos encoded
with h264
-------------------------------------+-------------------------------------
             Reporter:  mikffmpeg    |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  avcodec;     |               Blocked By:
  m1; mac; h264                      |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Comment (by Alex Agranovsky):

 This seems to happen, when the bitstream provided for decoding doesn't
 contain SPS/PPS.
 For example, using the provided `m1_not_decodable_with_acceleration.ts​`:
 {{{
 ffmpeg -i m1_not_decodable_with_acceleration.ts -vcodec copy
 m1_not_decodable_with_acceleration.h264
 ffmpeg -hwaccel videotoolbox -i m1_not_decodable_with_acceleration.h264 -v
 debug /tmp/img%05d.jpg
 }}}
 will still fail, but

 {{{
 ffmpeg -i m1_not_decodable_with_acceleration.ts -vcodec copy
 m1_not_decodable_with_acceleration.mkv
 ffmpeg -hwaccel videotoolbox -i m1_not_decodable_with_acceleration.mkv -v
 debug /tmp/img%05d.jpg
 }}}
 works. The difference seems to be what is fed into the decoder:

 {{{
 Broken with .h264 (and .ts):

 SPS-init - begin >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 67 4d 00 2a 9d a8 1e 00 89 f9 70 06 e0 20 20 28
 00 00 00 08 00 00 01 94 20
 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< SPS-init - end
 PPS-init - begin >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 68 ee 3c
 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< PPS-init - end
 decoding - begin >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 00 02 04 b7 65 b8 00 00 0e ab 00 cf f7 49 24 77

 Working with .mkv:

 SPS-init - begin >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 67 4d 00 2a 9d a8 1e 00 89 f9 70 06 e0 20 20 28
 00 00 00 08 00 00 01 94 20
 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< SPS-init - end
 PPS-init - begin >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 68 ee 3c
 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< PPS-init - end
 decoding - begin >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 00 00 00 02 09 f0 00 00 00 1b 67 4d 00 2a 9d a8
 1e 00 89 f9 70 06 e0 20 20 28 00 00 03 00 08 00
 00 03 01 94 20 00 00 00 04 68 ee 3c 80 00 00 00
 05 06 e5 01 41 80 00 02 04 b7 65 b8 00 00 0e ab
 00 cf f7 49 24 77 ... matches after this

 }}}

 As you see, there are SPS/PPS NALUs present in the bitstream provided when
 reading from mkv -- and that seems to make Apple gods happy.

 On Intel Mac, of course things work in all the above scenarios.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9713#comment:5>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker