[FFmpeg-trac] #10534(undetermined:new): Incorrect frame order when muxing H.264 stream with B-frames

[FFmpeg]

#10534: Incorrect frame order when muxing H.264 stream with B-frames
--------------------------------------+----------------------------------
             Reporter:  wdzierzan     |                     Type:  defect
               Status:  new           |                 Priority:  normal
            Component:  undetermined  |                  Version:  6.0
             Keywords:                |               Blocked By:
             Blocking:                |  Reproduced by developer:  0
Analyzed by developer:  0             |
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 Summary of the bug: The order of frames in an MP4 file is incorrect when
 an H.264 stream containing B-frames is muxed.

 How to reproduce:
 {{{
 % ffmpeg -i blob.h264 -vcodec copy blob.h264.mp4
 % ffmpeg -i blob.h264 -vcodec copy -bsf:v dts2pts blob.h264.pts.mp4

 ffmpeg version 6.0
   libavutil      58.  2.100 / 58.  2.100
   libavcodec     60.  3.100 / 60.  3.100
   libavformat    60.  3.100 / 60.  3.100
   libavdevice    60.  1.100 / 60.  1.100
   libavfilter     9.  3.100 /  9.  3.100
   libswscale      7.  1.100 /  7.  1.100
   libswresample   4. 10.100 /  4. 10.100
   libpostproc    57.  1.100 / 57.  1.100
 }}}

 Without the dts2pts filter, the initial I-frame is missing in the muxed
 file. pts_time as shown by ffprobe are non-monotonic (in decoding instead
 of presentation order?). Playback in `QuickTime` and popular web browsers
 is affected.

 AFAIU, the dts2pts filter is supposed to help for this case. It helps to
 some extent: the initial I-frame is preserved and pts_time are ''almost''
 monotonic. The issue is that they are not exactly monotonic (the order is
 broken around the middle and end of the file).

 Meanwhile, the output of
 {{{
 % MP4Box -add blob.h264 blob.h264.mp4box.mp4
 }}}
 seems fine.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10534>
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