[FFmpeg-trac] #3724(undetermined:new): Computed HLS duration is incorrect with short segment durations

FFmpeg trac at avcodec.org
Fri Jun 20 16:22:38 CEST 2014


#3724: Computed HLS duration is incorrect with short segment durations
-------------------------------------+-------------------------------------
             Reporter:  fthiery      |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:  hls          |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------

Comment (by fthiery):

 After further investigation, it seems that the merging is not related, but
 the encoding.

 After remuxing, reencoding audio, then video, it seems that the original
 h.264 encoding is
 the problem (gstreamer's x264enc with pass=5 quantizer=22 subme=4 key-int-
 max=30) because the problem only appears if it keep the original video
 bitstream (vcodec copy).

 The closest equivalent would be -r 30 -codec:v libx264 -crf 22 -x264opts
 keyint=30:subme=4, and it still does not reproduce the issue...

 On the reencoded file, there are non-regular gops (on scenecuts), but the
 problem doesn't appear.

 ||89.0||30||
 ||90.0||2||
 ||90.066667||28||
 ||91.0||30||
 ||92.0||30||

 If you are willing to take a look, the following video triggers the
 problem: http://d2hqzi4c71e9y2.cloudfront.net/moodlemoot/presentation-des-
 defis_83f8/presentation-des-defis_low.mp4

--
Ticket URL: <https://trac.ffmpeg.org/ticket/3724#comment:5>
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