[FFmpeg-trac] #7476(undetermined:new): Invalid pts and duration generated for mp4 when converting from webm

[FFmpeg]

#7476: Invalid pts and duration generated for mp4 when converting from webm
-------------------------------------+-------------------------------------
             Reporter:  jyavenard    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 How to reproduce:
 {{{
 % ffmpeg -i MozilleTest -c:v libx264 test.mp4

 ffmpeg version 4.02
 built on macos 10.13.6 (from brew)
 }}}

 Running ffprobe on the output:
 ffprobe -show_entries packet=pts_time,duration_time,stream_index
 ~/Downloads/test.mp4

 You can see that all frames have been marked with a duration of 1ms only.
 {{{
 [PACKET]
 stream_index=0
 pts_time=0.000000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.004000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.002000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.001000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.003000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.008000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 }}}


 It actually looks like something weird is occurring with the webm
 demuxer/remuxer

 as simply remuxing the webm content into another:

 ffmpeg -i MozillaTest -c:v copy -c:a copy -t 10 test.webm

 Also produce a file where all video frames are marked as being 1ms long:

 {{{
 [PACKET]
 stream_index=0
 pts_time=0.001000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.036000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.065000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.097000
 duration_time=0.001000
 [/PACKET]
 [PACKET]
 stream_index=0
 pts_time=0.140000
 duration_time=0.001000
 [/PACKET]
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7476>
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