[FFmpeg-trac] #2245(undetermined:new): Speed difference when using -ss on similar MKVs when extracting frame image

FFmpeg trac at avcodec.org
Thu Feb 7 10:36:43 CET 2013


#2245: Speed difference when using -ss on similar MKVs when extracting frame image
-------------------------------------+-------------------------------------
             Reporter:  eelco        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:

 When using -ss on the input file, some MKVs are significantly slower than
 others, while they’re the same resolution. I would expect a small speed
 difference due to encoding differences, but in this case it’s about 6-8
 times.

 How to reproduce:
 {{{
 > time ./ffmpeg "-ss" "10" "-i" ~/Desktop/ffmpeg-ss-bug/slow-ss.mkv "-f"
 "image2" "-vframes" "1" /dev/null
 ffmpeg version N-49666-g4745194 Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Feb  7 2013 10:22:14 with llvm-gcc 4.2.1 (LLVM build
 2336.11.00)
   configuration: --prefix=/Users/eelco/Projects/Beamer/FFmpeg/build
 --enable-gpl --enable-version3 --enable-libx264 --disable-shared --enable-
 static --enable-libtheora --enable-libvorbis --enable-libvo-aacenc
 --disable-doc --extra-cflags='-DMACOSX_DEPLOYMENT_TARGET=10.6 -isysroot
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk
 -mmacosx-version-min=10.6
 -I/Users/eelco/Projects/Beamer/FFmpeg/build/include' --extra-
 ldflags='-isysroot
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk
 -mmacosx-version-min=10.6 -L/Users/eelco/Projects/Beamer/FFmpeg/build/lib'
   libavutil      52. 17.101 / 52. 17.101
   libavcodec     54. 91.101 / 54. 91.101
   libavformat    54. 61.104 / 54. 61.104
   libavdevice    54.  3.103 / 54.  3.103
   libavfilter     3. 35.101 /  3. 35.101
   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 '/Users/eelco/Desktop/ffmpeg-ss-bug/slow-
 ss.mkv':
   Metadata:
     ENCODER         : Lavf54.59.106
   Duration: 00:00:11.22, start: 0.000000, bitrate: 9890 kb/s
     Chapter #0.0: start 0.000000, end 11.000000
     Metadata:
       title           : 00:00:00.000
     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 (default)
     Metadata:
       title           : English TRUE-HD
       LANGUAGE        : eng
 Output #0, image2, to '/dev/null':
   Metadata:
     encoder         : Lavf54.61.104
     Chapter #0.0: start 0.000000, end 1.000000
     Metadata:
       title           : 00:00:00.000
     Stream #0:0(eng): Video: mjpeg, yuvj420p, 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 -> mjpeg)
 Press [q] to stop, [?] for help
 frame=    1 fps=0.4 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A dup=0
 drop=236
 video:50kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.043320%
         2.41 real         5.94 user         0.10 sys
 }}}

 VS.

 {{{
 > time ./ffmpeg "-ss" "10" "-i" ~/Desktop/ffmpeg-ss-bug/fast-ss.mkv "-f"
 "image2" "-vframes" "1" /dev/null
 ffmpeg version N-49666-g4745194 Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Feb  7 2013 10:22:14 with llvm-gcc 4.2.1 (LLVM build
 2336.11.00)
   configuration: --prefix=/Users/eelco/Projects/Beamer/FFmpeg/build
 --enable-gpl --enable-version3 --enable-libx264 --disable-shared --enable-
 static --enable-libtheora --enable-libvorbis --enable-libvo-aacenc
 --disable-doc --extra-cflags='-DMACOSX_DEPLOYMENT_TARGET=10.6 -isysroot
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk
 -mmacosx-version-min=10.6
 -I/Users/eelco/Projects/Beamer/FFmpeg/build/include' --extra-
 ldflags='-isysroot
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk
 -mmacosx-version-min=10.6 -L/Users/eelco/Projects/Beamer/FFmpeg/build/lib'
   libavutil      52. 17.101 / 52. 17.101
   libavcodec     54. 91.101 / 54. 91.101
   libavformat    54. 61.104 / 54. 61.104
   libavdevice    54.  3.103 / 54.  3.103
   libavfilter     3. 35.101 /  3. 35.101
   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 '/Users/eelco/Desktop/ffmpeg-ss-bug/fast-
 ss.mkv':
   Metadata:
     MAJOR_BRAND     : qt
     MINOR_VERSION   : 537199360
     COMPATIBLE_BRANDS: qt
     TIMECODE        : 00:00:00:00
     ENCODER         : Lavf54.59.106
   Duration: 00:00:11.08, start: 0.000000, bitrate: 14054 kb/s
     Stream #0:0(eng): Video: h264 (Main), yuv420p, 1920x1080, SAR 1:1 DAR
 16:9, 24 fps, 24 tbr, 1k tbn, 2k tbc (default)
     Metadata:
       CREATION_TIME   : 2008-05-27 18:40:35
       LANGUAGE        : eng
       HANDLER_NAME    : Apple Alias Data Handler
     Stream #0:1(eng): Audio: aac, 48000 Hz, 5.1, fltp (default)
     Metadata:
       CREATION_TIME   : 2008-05-27 18:40:35
       LANGUAGE        : eng
       HANDLER_NAME    : Apple Alias Data Handler
 Output #0, image2, to '/dev/null':
   Metadata:
     MAJOR_BRAND     : qt
     MINOR_VERSION   : 537199360
     COMPATIBLE_BRANDS: qt
     TIMECODE        : 00:00:00:00
     encoder         : Lavf54.61.104
     Stream #0:0(eng): Video: mjpeg, yuvj420p, 1920x1080 [SAR 1:1 DAR
 16:9], q=2-31, 200 kb/s, 90k tbn, 24 tbc (default)
     Metadata:
       CREATION_TIME   : 2008-05-27 18:40:35
       LANGUAGE        : eng
       HANDLER_NAME    : Apple Alias Data Handler
 Stream mapping:
   Stream #0:0 -> #0:0 (h264 -> mjpeg)
 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=21
 video:205kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.010488%
         0.42 real         0.70 user         0.07 sys
 }}}

 I’ll upload the sample files to the FTP server.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2245>
FFmpeg <http://ffmpeg.org>
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