[FFmpeg-trac] #3716(undetermined:open): ffmpeg can't seek to start of a mpeg video

FFmpeg trac at avcodec.org
Wed Dec 17 07:15:47 CET 2014

#3716: ffmpeg can't seek to start of a mpeg video
             Reporter:  hxuanyu      |                    Owner:
                 Type:  defect       |                   Status:  open
             Priority:  important    |                Component:
              Version:  git-master   |  undetermined
             Keywords:  mpegps seek  |               Resolution:
  regression                         |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |

Comment (by lvml):

 I think I am experiencing the same issue, with h.264 MP4 files that are
 recorded by a Panasonic LX100 camera.

 I took a short example video file using the camera, taking a shot of a
 screen showing a millisecond counter for easier identification of
 individual frames (the display refresh rate is 60Hz, the video taken with
 25fps, the clock display refreshed each 10ms, but the relevant result is
 that each frame shows a different number). You can download this (3.5 MB)
 video file [http://filebin.ca/1knlOxMESIbK/P1000457.MP4 here].

 When replayed in the camera, the first frame shown shows {{{time:
 3685ms}}} on the display.
 When replayed with software like [http://mpv.io/ mpv],
 [http://avidemux.org/ avidemux], [http://kdenlive.org kdenlive] or alike
 that uses ffmpeg as a library for video decoding, the first frames a not
 displayed, but instead the first frame shows {{{time: 3768ms}}} - and that
 is actually the third frame.

 I have looked at timestamp dump outputs of ffprobe and MP4Box, and it
 seems that while MP4Box shows reasonable DTS and CTS times, where the
 first frame is actually to be displayed, first, the ffprobe output shows
 implausible DTS and PTS timestamps - they are always the same, and that
 would mean to display a B-frame before the first I-frame is decoded!

 For reference, I have uploaded the output of ffprobe and MP4Box for this
 example video:
 [http://filebin.ca/1knnYtjW7Boa/P1000457_ffprobe.txt ffprobe output]
 [http://filebin.ca/1knnkRxfITxs/P1000457_ts.txt MP4Box output]

Ticket URL: <https://trac.ffmpeg.org/ticket/3716#comment:6>
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