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• Extracting metadata from incomplete video files

  17 juillet 2013, par npgall

  Can anyone tell me where metadata is stored in common video file formats ? And if it would be located towards the start of the file, or scattered throughout.

  I'm working with a remote object store containing a lot of video files and I want to extract metadata, in particular video duration and video dimensions from those files, without streaming the entire file contents to the local machine.

  I'm hoping that this metadata will be stored in the first X bytes of files, and so I can just fetch a byte range starting at the beginning instead of the whole file, passing this partial file data to ffprobe.

  For testing purposes I created a 22MB MP4 file, and used the following command to supply only the first 1MB of data to ffprobe :

  head -c1024K '2013-07-04 12.20.07.mp4' | ffprobe -

  It prints :

  avprobe version 0.8.6-4:0.8.6-0ubuntu0.12.04.1, Copyright (c) 2007-2013 the Libav developers
  
    built on Apr  2 2013 17:02:36 with gcc 4.6.3
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x1a6b7a0] stream 0, offset 0x10beab: partial file
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'pipe:':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 1947-07-04 11:20:07
  
    Duration: 00:00:09.84, start: 0.000000, bitrate: N/A
  
      Stream #0.0(eng): Video: h264 (High), yuv420p, 1920x1080, 20028 kb/s, PAR 65536:65536 DAR 16:9, 29.99 fps, 30 tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 1947-07-04 11:20:07
  
      Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 189 kb/s
  
      Metadata:
  
        creation_time   : 1947-07-04 11:20:07

  So I see the first 1MB was enough to extract video duration 9.84 seconds and video dimensions 1920x1080, even though ffprobe printed the warning about detecting a partial file. If I supply less than 1MB, it fails completely.

  Would this approach work for other common video file formats to reliably extract metadata, or do any common formats scatter metadata throughout the file ?

  I'm aware of the concept of container formats and that various codecs may be used represent the audio/video data inside those containers. I'm not familiar with the details though. So I guess the question may apply to common combinations of containers + codecs ? Thanks in advance.

• I have failed the make of Android-FFmpeg-Android

  5 juillet 2013, par Tsurumaru Makoto

  I am having trouble compiling Android-FFmpeg-Android with make command.

  I'm using the ndk : android-ndk-r8e-linux-x86.tar.bz2 and I have ffmpeg installed on my machine :

  [root@sv　ffmpeg]#cat /proc/version
  
  Linux version 2.6.18-8.1.14.el5 (brewbuilder@hs20-bc2-2.build.redhat.com)
  
   (gcc version 4.1.1 20070105 (Red Hat 4.1.1-52)) #1 SMP Tue Sep 25 11:45:53 EDT 2007
  
  
  
  [root@sv ffmpeg]# ffmpeg
  
  FFmpeg version SVN-r26402, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Jul  5 2013 11:45:24 with gcc 4.1.2 20080704 (Red Hat 4.1.2-54)
  
    configuration: --enable-shared --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-x11grab --enable-libfaac --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-libvpx --enable-pic
  
    libavutil     50.36. 0 / 50.36. 0
  
    libavcore      0.16. 1 /  0.16. 1
  
    libavcodec    52.108. 0 / 52.108. 0
  
    libavformat   52.93. 0 / 52.93. 0
  
    libavdevice   52. 2. 3 / 52. 2. 3
  
    libavfilter    1.74. 0 /  1.74. 0
  
    libswscale     0.12. 0 /  0.12. 0
  
    libpostproc   51. 2. 0 / 51. 2. 0
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
  
  
  
  Use -h to get full help or, even better, run 'man ffmpeg'

  I'm using following repository : https://github.com/chu888chu888/Android-FFmpeg-Android

  Where I get :

  [homepage@sv FFmpeg-Android-master]$ ./FFmpeg-Android.sh
  
  
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/as: /lib/libz.so.1: no version information available (required by
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/as)
  
  LD libavutil/libavutil.so.51
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: error: cannot open /tmp/vplayer/bin/../sysroot/usr/lib/libm.so: Unknown error 530
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: error: cannot open /tmp/vplayer/bin/../sysroot/usr/lib/libz.so: Unknown error 530
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: error: cannot open /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/libgcc.a: Unknown error 530
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: error: cannot open /tmp/vplayer/bin/../sysroot/usr/lib/libc.so: Unknown error 530
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: error: cannot open /tmp/vplayer/bin/../sysroot/usr/lib/libdl.so: Unknown error 530
  
  /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: error: cannot open /tmp/vplayer/bin/../lib/gcc/arm-linux-androideabi/4.6/libgcc.a: Unknown error 530
  
  collect2: ld returned 1 exit status
  
  make: *** [libavutil/libavutil.so.51] Error 1

  It is an error.

  [homepage@sv FFmpeg-Android-master]$ ls /tmp/vplayer/sysroot/usr/lib
  
  crtbegin_dynamic.o  libEGL.so        libandroid.so      liblog.so     libthread_db.so
  
  crtbegin_so.o       libGLESv1_CM.so  libc.a             libm.a        libz.so
  
  crtbegin_static.o   libGLESv2.so     libc.so            libm.so
  
  crtend_android.o    libOpenMAXAL.so  libdl.so           libstdc++.a
  
  crtend_so.o         libOpenSLES.so   libjnigraphics.so  libstdc++.so

  You can see that file is present. Can anyone advice a solution to this issue ?

• How to concatenate two videos w. ffmpeg — documented code not working

  2 mars 2014, par Jim Miller

  I'm trying to concatenate two videos with ffmpeg. Nothing fancy ; I just want one video that consists of video A immediately followed by video B.

  I've tried the code from How to concatenate (join, merge) media files on a freshly built and otherwise-working-fine install of ffmpeg 1.2.1 on Fedora 17, but the following error message appears :

  $ ffmpeg -i video_a.mov -i video_b.mov -filter_complex '[0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]' -map '[v]' -map '[a]' output.mp4
  
  
  
  ffmpeg version N-54271-g7f866c1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun 29 2013 11:05:42 with gcc 4.7.2 (GCC) 20120921 (Red Hat 4.7.2-2)
  
    configuration: --enable-gpl --enable-nonfree --enable-pthreads --enable-libx264 --enable-libfaac --extra-cflags=-I/usr/local/include --extra-ldflags=-L/usr/local/lib
  
    libavutil      52. 37.101 / 52. 37.101
  
    libavcodec     55. 17.100 / 55. 17.100
  
    libavformat    55. 10.100 / 55. 10.100
  
    libavdevice    55.  2.100 / 55.  2.100
  
    libavfilter     3. 77.101 /  3. 77.101
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  3.100 / 52.  3.100
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'v1221-MTQxMzcyNTIxODU2.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2013-03-28 20:34:59
  
      encoder         : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
      encoder-eng     : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
    Duration: 00:00:05.34, start: 0.000000, bitrate: 15837 kb/s
  
      Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 221 kb/s
  
      Metadata:
  
        creation_time   : 2013-03-28 20:34:59
  
        handler_name    : Core Media Data Handler
  
      Stream #0:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 15512 kb/s, 29.81 fps, 30 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2013-03-28 20:34:59
  
        handler_name    : Core Media Data Handler
  
  
  
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'v1224-MTQxMzcyNTIxODg5.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2013-03-28 20:36:28
  
      encoder         : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
      encoder-eng     : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
    Duration: 00:00:04.13, start: 0.000000, bitrate: 15689 kb/s
  
      Stream #1:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 221 kb/s
  
      Metadata:
  
        creation_time   : 2013-03-28 20:36:28
  
        handler_name    : Core Media Data Handler
  
      Stream #1:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 15446 kb/s, 29.79 fps, 30 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2013-03-28 20:36:28
  
        handler_name    : Core Media Data Handler
  
  
  
  Stream specifier ':0' in filtergraph description [0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a] matches no streams.

  A few other things to note :

  • The two videos I'm working with were shot with the same camera, so there shouldn't be any problems with aspect ratio or other gory video details.
  • I'm able to do other things with my ffmpeg installation, like convert one of those videos from .mov to .mp4 (yes, I had to recompile with faac...), which seems to vouch for both the ffmpeg and the video.
  • I've tried modifying the above invocation to produce a .mov file at the end, but I get the same error as before.
  • I've tried some stupid hacking tricks on the request above, like concatenating two copies of the same video, as well as some other invocations from other places around the web that involve filter_complex. Even on ones that were cited as working, I get the "matches no streams" message.