[FFmpeg-trac] #2263(avformat:open): Read second SeekHead in Matroska files

FFmpeg trac at avcodec.org
Tue Mar 19 01:43:35 CET 2013


#2263: Read second SeekHead in Matroska files
-------------------------------------+------------------------------------
             Reporter:  eelco        |                    Owner:
                 Type:  enhancement  |                   Status:  open
             Priority:  wish         |                Component:  avformat
              Version:  git-master   |               Resolution:
             Keywords:  mkv h264     |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+------------------------------------

Comment (by cehoyos):

 mosu has kindly produced a small sample that allows to reproduce the
 problem:
 {{{
 $ mkvmerge -o out.mkv seekhead-at-end.mkv
 }}}
 {{{
 $ ffmpeg -ss 26.4 -i seekhead-at-end.mkv -vframes 1 outslow.png
 ffmpeg version N-51078-g6128d33 Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Mar 19 2013 00:53:13 with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl --disable-indev=jack
   libavutil      52. 19.101 / 52. 19.101
   libavcodec     55.  1.100 / 55.  1.100
   libavformat    55.  0.100 / 55.  0.100
   libavdevice    55.  0.100 / 55.  0.100
   libavfilter     3. 47.103 /  3. 47.103
   libswscale      2.  2.100 /  2.  2.100
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  2.100 / 52.  2.100
 Input #0, matroska,webm, from 'seekhead-at-end.mkv':
   Metadata:
     creation_time   : 2013-03-18 12:09:06
   Duration: 00:00:30.24, start: 0.000000, bitrate: 469 kb/s
     Chapter #0.0: start 0.000000, end 15.000000
     Metadata:
       title           : Chapter 01
     Chapter #0.1: start 15.000000, end 30.241000
     Metadata:
       title           : Chapter 02
     Chapter #0.2: start 754.567000, end 30.241000
     Metadata:
       title           : Chapter 03
     Chapter #0.3: start 1200.000000, end 30.241000
     Metadata:
       title           : Chapter 04
     Chapter #0.4: start 3723.040000, end 30.241000
     Metadata:
       title           : Chapter 05
     Stream #0:0: Video: h264 (Main), yuv420p, 640x352 [SAR 1:1 DAR 20:11],
 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
     Stream #0:1: Audio: aac, 48000 Hz, stereo, fltp (default)
 Output #0, image2, to 'outslow.png':
   Metadata:
     encoder         : Lavf55.0.100
     Chapter #0.0: start 0.000000, end 3.841000
     Metadata:
       title           : Chapter 02
     Chapter #0.1: start 728.167000, end 3.841000
     Metadata:
       title           : Chapter 03
     Chapter #0.2: start 1173.600000, end 3.841000
     Metadata:
       title           : Chapter 04
     Chapter #0.3: start 3696.640000, end 3.841000
     Metadata:
       title           : Chapter 05
     Stream #0:0: Video: png, rgb24, 640x352 [SAR 1:1 DAR 20:11], q=2-31,
 200 kb/s, 90k tbn, 23.98 tbc (default)
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 -> png)
 Press [q] to stop, [?] for help
 frame=    1 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A dup=0
 drop=631
 video:128kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.016844%

 real    0m0.248s
 user    0m0.827s
 sys     0m0.021s
 }}}
 {{{
 $ ffmpeg -ss 26.4 -i out.mkv -vframes 1 outfast.png
 ffmpeg version N-51078-g6128d33 Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Mar 19 2013 00:53:13 with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl --disable-indev=jack
   libavutil      52. 19.101 / 52. 19.101
   libavcodec     55.  1.100 / 55.  1.100
   libavformat    55.  0.100 / 55.  0.100
   libavdevice    55.  0.100 / 55.  0.100
   libavfilter     3. 47.103 /  3. 47.103
   libswscale      2.  2.100 /  2.  2.100
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  2.100 / 52.  2.100
 Input #0, matroska,webm, from 'out.mkv':
   Metadata:
     creation_time   : 2013-03-18 23:50:20
   Duration: 00:00:30.24, start: 0.000000, bitrate: 468 kb/s
     Chapter #0.0: start 0.000000, end 15.000000
     Metadata:
       title           : Chapter 01
     Chapter #0.1: start 15.000000, end 30.241000
     Metadata:
       title           : Chapter 02
     Chapter #0.2: start 754.567000, end 30.241000
     Metadata:
       title           : Chapter 03
     Chapter #0.3: start 1200.000000, end 30.241000
     Metadata:
       title           : Chapter 04
     Chapter #0.4: start 3723.040000, end 30.241000
     Metadata:
       title           : Chapter 05
     Stream #0:0: Video: h264 (Main), yuv420p, 640x352 [SAR 1:1 DAR 20:11],
 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
     Stream #0:1: Audio: aac, 48000 Hz, stereo, fltp (default)
 Output #0, image2, to 'outfast.png':
   Metadata:
     encoder         : Lavf55.0.100
     Chapter #0.0: start 0.000000, end 3.841000
     Metadata:
       title           : Chapter 02
     Chapter #0.1: start 728.167000, end 3.841000
     Metadata:
       title           : Chapter 03
     Chapter #0.2: start 1173.600000, end 3.841000
     Metadata:
       title           : Chapter 04
     Chapter #0.3: start 3696.640000, end 3.841000
     Metadata:
       title           : Chapter 05
     Stream #0:0: Video: png, rgb24, 640x352 [SAR 1:1 DAR 20:11], q=2-31,
 200 kb/s, 90k tbn, 23.98 tbc (default)
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 -> png)
 Press [q] to stop, [?] for help
 frame=    1 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
 video:128kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.016844%

 real    0m0.040s
 user    0m0.033s
 sys     0m0.018s
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2263#comment:10>
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