[FFmpeg-trac] #9481(undetermined:new): VA-API + QSV H264 => MPEG2 transcode PSNR dropped by 25%

[FFmpeg]

#9481: VA-API + QSV H264 => MPEG2 transcode PSNR dropped by 25%
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             Reporter:  eero-t       |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  unspecified  |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by Balling):

 You need to set all (at least 3) parameters for PSNR for it to work on the
 same frames. Please also rename an issue.

 I will quote Paul on this:

 "Use "setpts=PTS-STARTPTS,split=2[a][b],[a][1:v]ssim;[b][1:v]psnr".
 Your first input pts does not start from 0.

 You also need to use settb to set both inputs to same timebase, and do
 that before using setpts filters."
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Ticket URL: <https://trac.ffmpeg.org/ticket/9481#comment:6>
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