[FFmpeg-trac] #2263(avformat:open): MKV: keyframe not used when using -ss on input?

FFmpeg trac at avcodec.org
Wed Feb 13 21:59:43 CET 2013


#2263: MKV: keyframe not used when using -ss on input?
------------------------------------+------------------------------------
             Reporter:  eelco       |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avformat
              Version:  git-master  |               Resolution:
             Keywords:  mkv h264    |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
------------------------------------+------------------------------------
Changes (by cehoyos):

 * status:  new => open
 * component:  undetermined => avformat


Comment:

 I can confirm that seeking in the file takes ridiculously long, this can
 be fixed by remuxing (both FFmpeg and mkvmerge). I don't know enough about
 Matroska to explain what is "wrong" about the file but mkvalidator reports
 the following:
 {{{
 $ mkvalidator 2263-slow-ss-full.mkv
 WRN103: Unnecessary secondary SeekHead was found at 11568150341
 WRN861: The SegmentInfo is not referenced in the main SeekHead
 WRN861: The TrackInfo is not referenced in the main SeekHead
 WRN861: The Cues is not referenced in the main SeekHead
 WRN861: The Chapters is not referenced in the main SeekHead
 WRN0D0: There are 4618 bytes of void data................................

 mkvalidator 0.4.0: the file appears to be valid
         file created with libebml v1.2.3 + libmatroska v1.3.0 / mkvmerge
 v5.8.0 ('No Sleep / P
 illow') built on Sep  2 2012 15:37:04
 }}}
 {{{
 $ ffmpeg -ss 0:30:00 -i 2263-slow-ss-full.mkv -vframes 1 out.png
 ffmpeg version N-49888-gafe30fe Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Feb 13 2013 12:23:23 with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl --disable-indev=jack
   libavutil      52. 17.101 / 52. 17.101
   libavcodec     54. 91.103 / 54. 91.103
   libavformat    54. 63.100 / 54. 63.100
   libavdevice    54.  3.103 / 54.  3.103
   libavfilter     3. 37.101 /  3. 37.101
   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 '2263-slow-ss-full.mkv':
   Metadata:
     creation_time   : 2012-12-09 16:32:15
   Duration: 01:33:24.19, start: 0.000000, bitrate: 16513 kb/s
     Chapter #0.0: start 0.000000, end 316.316000
     Metadata:
       title           : 00:00:00.000
     Chapter #0.1: start 316.316000, end 651.985000
     Metadata:
       title           : 00:05:16.316
     Chapter #0.2: start 651.985000, end 1186.310000
     Metadata:
       title           : 00:10:51.985
     Chapter #0.3: start 1186.310000, end 1669.835000
     Metadata:
       title           : 00:19:46.310
     Chapter #0.4: start 1669.835000, end 1970.552000
     Metadata:
       title           : 00:27:49.835
     Chapter #0.5: start 1970.552000, end 2434.974000
     Metadata:
       title           : 00:32:50.552
     Chapter #0.6: start 2434.974000, end 2811.976000
     Metadata:
       title           : 00:40:34.974
     Chapter #0.7: start 2811.976000, end 3120.534000
     Metadata:
       title           : 00:46:51.976
     Chapter #0.8: start 3120.534000, end 3535.157000
     Metadata:
       title           : 00:52:00.534
     Chapter #0.9: start 3535.157000, end 3623.411000
     Metadata:
       title           : 00:58:55.157
     Chapter #0.10: start 3623.411000, end 3859.314000
     Metadata:
       title           : 01:00:23.411
     Chapter #0.11: start 3859.314000, end 4259.672000
     Metadata:
       title           : 01:04:19.314
     Chapter #0.12: start 4259.672000, end 4530.317000
     Metadata:
       title           : 01:10:59.672
     Chapter #0.13: start 4530.317000, end 4869.782000
     Metadata:
       title           : 01:15:30.317
     Chapter #0.14: start 4869.782000, end 4968.630000
     Metadata:
       title           : 01:21:09.782
     Chapter #0.15: start 4968.630000, end 5604.192000
     Metadata:
       title           : 01:22:48.630
     Stream #0:0(eng): Video: h264 (High), yuv420p, 1920x1080, SAR 1:1 DAR
 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
     Stream #0:1(eng): Audio: truehd, 48000 Hz, 7.1, s32
     Metadata:
       title           : English TRUE-HD
     Stream #0:2(swe): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s
 (default)
     Metadata:
       title           : Swedish AC3
     Stream #0:3(swe): Subtitle: dvd_subtitle (default)
     Metadata:
       title           : Swedish
     Stream #0:4(eng): Subtitle: dvd_subtitle
     Metadata:
       title           : English
 Output #0, image2, to 'out.png':
   Metadata:
     encoder         : Lavf54.63.100
     Chapter #0.0: start 0.000000, end 170.552000
     Metadata:
       title           : 00:27:49.835
     Chapter #0.1: start 170.552000, end 634.974000
     Metadata:
       title           : 00:32:50.552
     Chapter #0.2: start 634.974000, end 1011.976000
     Metadata:
       title           : 00:40:34.974
     Chapter #0.3: start 1011.976000, end 1320.534000
     Metadata:
       title           : 00:46:51.976
     Chapter #0.4: start 1320.534000, end 1735.157000
     Metadata:
       title           : 00:52:00.534
     Chapter #0.5: start 1735.157000, end 1823.411000
     Metadata:
       title           : 00:58:55.157
     Chapter #0.6: start 1823.411000, end 2059.314000
     Metadata:
       title           : 01:00:23.411
     Chapter #0.7: start 2059.314000, end 2459.672000
     Metadata:
       title           : 01:04:19.314
     Chapter #0.8: start 2459.672000, end 2730.317000
     Metadata:
       title           : 01:10:59.672
     Chapter #0.9: start 2730.317000, end 3069.782000
     Metadata:
       title           : 01:15:30.317
     Chapter #0.10: start 3069.782000, end 3168.630000
     Metadata:
       title           : 01:21:09.782
     Chapter #0.11: start 3168.630000, end 3804.192000
     Metadata:
       title           : 01:22:48.630
     Stream #0:0(eng): Video: png, rgb24, 1920x1080 [SAR 1:1 DAR 16:9],
 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=43155
 video:4216kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.000510%

 real    2m42.727s
 user    15m2.405s
 sys     0m6.223s
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2263#comment:7>
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