[FFmpeg-trac] #10062(undetermined:new): av1_qsv produces incorrect output files

FFmpeg trac at avcodec.org
Sat Nov 26 11:59:16 EET 2022


#10062: av1_qsv produces incorrect output files
-------------------------------------+-------------------------------------
             Reporter:  oviano       |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  qsv          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Comment (by oviano):

 Ok, I'll try and explain again:

 1. the hardware is outputting frames in DTS order (increasing each time),
 but the PTS is not in order
 2. AV1 does not have AV_CODEC_PROP_REORDER set
 3. There is code in FFmpeg (ff_encode_encode_cb) that sees this flag is
 not set, and sets DTS = PTS:

         if (!(avctx->codec_descriptor->props & AV_CODEC_PROP_REORDER) ||
             !(avctx->codec->capabilities & AV_CODEC_CAP_DELAY))
             avpkt->dts = avpkt->pts;

 4. This means the DTS is no longer in order (because it was set to PTS
 which is out of order) and thus produces the errors

 Note that QSVEnc produces correct files from the same input.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10062#comment:5>
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