[FFmpeg-trac] #3697(undetermined:new): H264/MPEGTS avg_frame_rate inconsistencies

[FFmpeg]

#3697: H264/MPEGTS avg_frame_rate inconsistencies
-------------------------------------+-------------------------------------
             Reporter:  bog          |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 When transcoding h264 in mp4 with non-whole frame rates to mpegts and
 back, the avg_frame_rate and packet duration is altered. This can be
 problematic when concatenating multiple mp4s with the concat protocol with
 the same settings because the avg_frame_rate is not normalized.

 How to reproduce:
 I'm working with this ffmpeg:
 {{{
 ffmpeg version N-63724-g5766543 Copyright (c) 2000-2014 the FFmpeg
 developers
   built on Jun  3 2014 07:41:35 with Apple LLVM version 5.1
 (clang-503.0.40) (based on LLVM 3.4svn)
   configuration: --enable-gpl --enable-postproc --disable-debug --enable-
 libmp3lame --enable-libfdk_aac --enable-pthreads --enable-libx264
 --enable-libvpx --enable-nonfree --enable-libass --enable-libfreetype
 --enable-static --extra-libs=-ldl
 }}}

 The file below is 23.976fps content. avg_frame_rate reported by ffprobe is
 2997/125. The pkt_duration_time is 0.041708.
 {{{
 ffmpeg -i http://ted.conferences.s3.amazonaws.com/test/outro.mp4 -c copy
 -bsf:v h264_mp4toannexb -f mpegts test.ts
 ffprobe -show_streams -select_streams v:0 test.ts 2>/dev/null | grep
 avg_frame_rate
 }}}

 ffprobe outputs: avg_frame_rate=24000/1001. I think this change is ok, but
 I wanted to include it. The video pkt_duration_time is now 0.041700.

 Next, we transcode the video back to mp4:

 {{{
 ffmpeg -i test.ts -c copy -bsf:a aac_adtstoasc test.mp4
 ffprobe -show_streams -select_streams v:0 test.mp4 2>/dev/null | grep
 avg_frame_rate
 }}}

 ffprobe outputs: avg_frame_rate=10980000/457957. The video
 pkt_duration_time is still 0.041700.

 The avg_frame_rate is different for each file I bring through this
 process.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/3697>
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