[FFmpeg-trac] #4554(undetermined:new): wrong seek with -ss

[FFmpeg]

#4554: wrong seek with -ss
-------------------------------------+-------------------------------------
             Reporter:               |                     Type:  defect
  josephine.dussourd                 |                 Priority:  normal
               Status:  new          |                  Version:
            Component:               |  unspecified
  undetermined                       |               Blocked By:
             Keywords:               |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 I’m trying to extract a particular frame from my video but I don’t get the
 frame I expect:
 The video encoded in h.264, and have 25 fps. The timecode is burn in my
 video
  00:00:00.88 correspond to 14:53:07:12 brunt in my video, but when I seek
 the next frame I don’t have the actual next frame :
 {{{
 ffmpeg -ss 00:00:00.88 -i myVideo.mp4 -frames:v 1 sec088.jpg
         gives me the frame with the timecode 14:53:07:12
 ffmpeg -ss 00:00:00.92 -i myVideo.mp4 -frames:v 1 sec092.jpg
         gives me the frame with the timecode 14:53:07:15
 ffmpeg -ss 00:00:00.96 -i myVideo.mp4 -frames:v 1 sec096.jpg
         gives me the frame with the timecode 14:53:07:15
 ffmpeg -ss 00:00:01 -i myVideo.mp4 -frames:v 1 sec100.jpg
         gives me the frame with the timecode 14:53:07:15
 ffmpeg -ss 00:00:01.04 -i myVideo.mp4 -frames:v 1 sec104.jpg
         gives me the frame with the timecode 14:53:07:16
 }}}
 I decided to extract the images from the video with this command line:
 {{{ffmpeg -i myVideo.mp4 c:/images/image%06d.jpg}}}
 When I checked the images, the frames with the time code 14:53:07:13 and
 14:53:07:14 exist.


 ffmpeg -v 9 -loglevel 99 -i myVideo.mp4
 {{{
 ffmpeg version N-71209-gd759844 Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 4.9.2 (GCC)
   configuration: --enable-gpl --enable-version3 --disable-w32threads
 --enable-av
 isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls
 --enab
 le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-
 libcaca --
 enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm
 --enable-l
 ibilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb
 --enab
 le-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-
 librtmp --en
 able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora
 --ena
 ble-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-
 amrwbenc
  --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
 --enabl
 e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma
 --ena
 ble-decklink --enable-zlib
   libavutil      54. 22.100 / 54. 22.100
   libavcodec     56. 32.100 / 56. 32.100
   libavformat    56. 27.100 / 56. 27.100
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5. 13.101 /  5. 13.101
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  1.100 /  1.  1.100
   libpostproc    53.  3.100 / 53.  3.100
 Splitting the commandline.
 Reading option '-v' ... matched as option 'v' (set logging level) with
 argument
 '9'.
 Reading option '-loglevel' ... matched as option 'loglevel' (set logging
 level)
 with argument '99'.
 Reading option '-i' ... matched as input file with argument 'myVideo.mp4'.
 Finished splitting the commandline.
 Parsing a group of options: global .
 Applying option v (set logging level) with argument 9.
 Successfully parsed a group of options.
 Parsing a group of options: input file myVideo.mp4.
 Successfully parsed a group of options.
 Opening an input file: myVideo.mp4.
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0000000000316440] Format
 mov,mp4,m4a,3gp,3g2,mj2 prob
 ed with size=2048 and score=100
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0000000000316440] ISO: File Type Major Brand:
 isom
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0000000000316440] Before
 avformat_find_stream_info()
 pos: 7557884 bytes read:50882 seeks:1
 [h264 @ 0000000000327f20] no picture
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0000000000316440] All info found
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0000000000316440] After
 avformat_find_stream_info() p
 os: 20381 bytes read:83650 seeks:2 frames:1
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'myVideo.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf56.27.100
   Duration: 00:01:00.08, start: 0.000000, bitrate: 1006 kb/s
     Stream #0:0(eng), 1, 1/25000: Video: h264 (Main), 4 reference frames
 (avc1 /
  0x31637661), yuv420p(tv, left), 640x360 (640x368) [SAR 1:1 DAR 16:9],
 1/50, 100
 3 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
     Metadata:
       handler_name    : VideoHandler
 Successfully opened the file.
 At least one output file must be specified
 [AVIOContext @ 0000000000316cc0] Statistics: 83650 bytes read, 2 seeks
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4554>
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