[FFmpeg-trac] #8523(avformat:open): ffmpeg converts 30fps input to 29.97fps when converting to .mxf

[FFmpeg]

#8523: ffmpeg converts 30fps input to 29.97fps when converting to .mxf
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             Reporter:  reakon      |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  mxf         |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by Tjoppen):

 Replying to [comment:10 reakon]:
 > The closest to a spec I can find is a mention about IEC61937-14:2017
 standard in kexoplayer's source code covering similar functionality.
 Though, since rates for 30/1.001 an 60/1.001 are already defined, we can
 calculate average rate for remaining 120/1.001 as such:
 >
 > {{{
 > samplerate/framerate = samples/frames = 48000/(120/1.001) = 4004/10 =
 400.4
 > }}}
 >
 > Spreading it to 5 frames would give 2x 401 sample frames and 3x 400
 frames. I'm not sure if these should be put in a specific sequence tho.

 Alternating them similar to what is done now is probably OK, even if I
 would like to see a spec. Please give the attached patch a go. I don't
 have any suitable material for it, but it passes FATE at least.

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Ticket URL: <https://trac.ffmpeg.org/ticket/8523#comment:12>
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