[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  |                     Type:  defect
               Status:  new        |                 Priority:  normal
            Component:  avcodec    |                  Version:  git-master
             Keywords:             |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
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 '''Summary of the bug:'''
 Using hardware acceleration (i.e. videotoolbox) to decode the frames of
 some video streams encoded with h264 fails on recent M1 mac computers.

 '''How to reproduce:'''
 Ensure you are using a Mac with an Apple M1 chip.
 Download the attached sample file and use ffmpeg to target it with
 {{{
 % ffmpeg -hwaccel videotoolbox -i m1_not_decodable_with_acceleration.ts
 -an output.ts
 }}}
 The terminal will then repeatedly print
 {{{
 [h264 @ 0x7f85b5f32ec0] hardware accelerator failed to decode picture
 Error while decoding stream #0:0: Unknown error occurred
 }}}

 '''Other details:'''
 This bug does not occur with all videos encoded with h264. Although the
 issue can be reproduced with the most recent ffmpeg binary (version
 N-106494-g1291568c98-tessus), when looking at the source code FFmpeg 3.3,
 it seems that the failure is caused by a call to
 [https://developer.apple.com/documentation/videotoolbox/1536071-vtdecompressionsessiondecodefram?language=objc/
 VTDecompressionSessionDecodeFrame]. This call does not return an error
 code, but it alters the videotoolbox context's state so as not to fail on
 a null pointer check.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9713>
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