[FFmpeg-trac] #10468(avfilter:new): lavfi/vpp_qsv: regression in setting of time_base

[FFmpeg]

#10468: lavfi/vpp_qsv: regression in setting of time_base
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             Reporter:  Øystein Sture  |                     Type:  defect
               Status:  new            |                 Priority:  normal
            Component:  avfilter       |                  Version:  6.0
             Keywords:  VPP_QSV        |               Blocked By:
             Blocking:                 |  Reproduced by developer:  0
Analyzed by developer:  0              |
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 Summary of the bug:
 The following commit changed the default parameters for frame rate and
 time base
 https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/077e63496581edf02e503e7d99dbc4e1a5670246

 As a part of these changes, the outlink time_base is set to the inverse of
 the estimated frame rate, regardless of if these new features with
 deinterlacing or frame rate control is used or not. When upgrading to
 ffmpeg 6.0, the encoder started complaining that the pts was not
 monotonously increasing with variable frame rate (since the new time_base
 is effectively 1/avg_frame_rate).

 How to reproduce:
 An easy way to reproduce the regression is to omit setting the frame_rate
 parameter of the buffersrc filter, thus using the default of 0/1. The
 vpp_qsv filter will still try to set the time_base to the inverse of frame
 rate, ending up with 1/0 time base and no valid output pts from the filter
 graph (always 0). I'm using the C-api directly, so I don't have an ffmpeg
 command on hand to illustrate the problem, but it should be fairly obvious
 looking at the code.

 Not sure what priority to assign to this, but it's present both in master
 and release/6.0.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10468>
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