[FFmpeg-trac] #7025(undetermined:new): Framerate changes when using prores and copy codec

[FFmpeg]

#7025: Framerate changes when using prores and copy codec
-------------------------------------+-------------------------------------
             Reporter:               |                     Type:  defect
  FrugalCourtland                    |                 Priority:  normal
               Status:  new          |                  Version:
            Component:               |               Blocked By:
  undetermined                       |  Reproduced by developer:  0
             Keywords:               |
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:

 Framerate changes when using the "copy" command with a prores video, when
 the length of the video doesn't land on a clean second boundary. In this
 example, the input video is 4 frames. FFProbe will show the framerate at
 30 fps, but after copying, the framerate changes to slightly less than 30.

 How to reproduce:
 {{{
 % ffprobe input.mov
 }}}
     Stream #0:0(eng): Video: prores (apcn / 0x6E637061),
 yuv422p10le(progressive), 100x62, 92 kb/s, SAR 1:1 DAR 50:31, '''30
 fps''', 30 tbr, 15360 tbn, 15360 tbc (default)

 {{{
 % ffmpeg -i input.mov -c:v copy output.mov
 % ffprobe output.mov
 }}}

     Stream #0:0(eng): Video: prores (ap4h / 0x68347061),
 yuv444p10le(progressive), 100x62, 91 kb/s, SAR 1:1 DAR 50:31, '''29.85
 fps''', 30 tbr, 15360 tbn, 15360 tbc (default)

 {{{
 ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
   built with gcc 7.2.0 (GCC)
 ffprobe version 3.4.1 Copyright (c) 2007-2017 the FFmpeg developers
   built with gcc 7.2.0 (GCC)
 }}}

 The video was originally created with this command:
 {{{
 % ffmpeg -framerate 30 -i %02d.png -codec prores input.mov
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7025>
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