[FFmpeg-trac] #3199(undetermined:new): duration incorrect for mpeg file

[FFmpeg]

#3199: duration incorrect for mpeg file
-------------------------------------+-------------------------------------
             Reporter:  DonMoir      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 The file dolbycity.vob has an audio, video, and data stream. The audio and
 video streams have different durations.

 The duration computed in ../libavformat/utils.c in
 estimate_timings_from_pts seems to take first stream it finds and computes
 that stream duration and this is then propagated to the other streams. The
 real audio stream duration is 31808 ms. The video stream duration is 32000
 ms. Seems estimate_timings_from_pts computes the audio stream duration at
 31776 since it lacks the duration of the last packet in it's calculation.
 31776 + 32 = 31808. 32 is the duration of the last audio packet in ms.

 So estimate_timings_from_pts seems to be overkill and not enough ( at same
 time :) to get accurate results.

 I think mediainfo is the only program I have that reports the audio
 duration at 31808 and video duration at 32000 and overall duration at
 32000. But I verified those numbers by walking the packet list. It's
 important I get these durations as exact as possible and for this
 particular case it is possible but not happening.

 http://sms.pangolin.com/temp/dolbycity.vob

 ffmpeg -i dolbycity.vob
 ffmpeg version N-58733-gf65afef Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Dec  3 2013 22:04:42 with gcc 4.8.2 (GCC)
   configuration: --disable-static --enable-shared
     --enable-gpl --enable-version3 --disable-w32threads
     --enable-avisynth --enable-bzlib --enable-fontconfig
     --enable-frei0r --enable-gnutls --enable-iconv
     --enable-libass --enable-libbluray --enable-libcaca
     --enable-libfreetype --enable-libgsm --enable-libilbc
     --enable-libmodplug --enable-libmp3lame
     --enable-libopencore-amrnb
     --enable-libopencore-amrw
 b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-
 libschroedinge
 r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-
 libtwolame --en
 able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-
 libvorbis
  --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libxavs
 --enable-
 libxvid --enable-zlib
   libavutil      52. 56.100 / 52. 56.100
   libavcodec     55. 45.100 / 55. 45.100
   libavformat    55. 22.100 / 55. 22.100
   libavdevice    55.  5.102 / 55.  5.102
   libavfilter     3. 91.100 /  3. 91.100
   libswscale      2.  5.101 /  2.  5.101
   libswresample   0. 17.104 /  0. 17.104
   libpostproc    52.  3.100 / 52.  3.100
 Input #0, mpeg, from 'dolbycity.vob':
   Duration: 00:00:31.78, start: 0.049756, bitrate: 5291 kb/s
     Stream #0:0[0x1bf]: Data: dvd_nav_packet
     Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv), 720x576
 [SAR 16:1
 5 DAR 4:3], max. 9800 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
     Stream #0:2[0x80]: Audio: ac3, 48000 Hz, 5.1(side), fltp, 384 kb/s

--
Ticket URL: <https://trac.ffmpeg.org/ticket/3199>
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