[FFmpeg-trac] #9382(undetermined:new): Wrong TB returned for use in '-bsf setts'

[FFmpeg]

#9382: Wrong TB returned for use in '-bsf setts'
-------------------------------------+-------------------------------------
             Reporter:  markfilipak  |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 (0) This command:
 {{{
 ffmpeg -i
 "concat:VTS_04_1.VOB|VTS_04_2.VOB|VTS_04_3.VOB|VTS_04_4.VOB|VTS_04_5.VOB|VTS_04_6.VOB"
 \
 -map 0 -codec copy -dn "(0).mkv"
 provokes "Can't write packet with unknown timestamp" and aborts. To
 overcome that, I'll use a bitstream filter.
 }}}
 (1) However, this command:
 {{{
 ffmpeg -i
 "concat:VTS_04_1.VOB|VTS_04_2.VOB|VTS_04_3.VOB|VTS_04_4.VOB|VTS_04_5.VOB|VTS_04_6.VOB"
 \
 -bsf "setts=pts=N/TB*1001/24000:dts=N/TB*1001/24000" -map 0 -codec copy
 -dn "(1).mkv"
 doesn't work as expected -- MPV reports "FPS: 29.583 (specified) 0.266
 (estimated)" and playback is very, very slow.
 \___=23.976*1000/90000
 }}}
 (2) But this command:
 {{{
 ffmpeg -i
 "concat:VTS_04_1.VOB|VTS_04_2.VOB|VTS_04_3.VOB|VTS_04_4.VOB|VTS_04_5.VOB|VTS_04_6.VOB"
 \
 -bsf "setts=pts=N/(1/1000)*1001/24000:dts=N/(1/1000)*1001/24000" -map 0
 -codec copy -dn "(2).mkv"
 does work as expected -- MPV reports "FPS: 29.583 (specified) 23.976
 (estimated)" and playback is normal.
 }}}


 Why doesn't (1) work? Because the value of 'TB' that's returned and used
 is the '''_decoder_'s time base''': 1/90000.
 But it needs to be the value of the '''_encoder_'s time base''': 1/1000,
 as proven by (2).
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9382>
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