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• ffmpeg problem in ubuntu (libavcodec.so)

  7 décembre 2016, par lyuba

  I run Ubuntu and try to use the ffmpeg wrapper in Java from here :
  http://code.google.com/p/javacv/

  It seems to work fine on other systems, but in Ubuntu the project crashes
  with the following mistake :
  Exception in thread "main" java.lang.UnsatisfiedLinkError : Error looking up
  function ’avcodec_decode_video2’ : /usr/lib/i686/cmov/libavcodec.so :
  undefined symbol : avcodec_decode_video2

  ffmpeg is working great from the command line, though.

  JavaCV author recommended me to check this link :
  http://linux-tipps.blogspot.com/2009/05/pretending-package-is-installed-by.html

  Probably I’m doing something wrong, but it cannot reinstall libavcodec51
  like this.

  So the questions are :
  1. Is those solution above a good one so I should bring it to success
  somehow ?
  2. What are the other ways to solve the problem ?

  Thank you for your suggestions in advance !

• How do I extract color matrix from MP4 an x264 stream in Media Foundation

  23 août 2016, par Jules

  I am playing a video (mp4 containing x264 encoded video stream) with a custom player using media foundation.

  When I convert the YUV information into RGB I need to account for the color matrix and range used at encode time.

  Some of my videos have this information, I can use MediaInfo.exe or FFMPEG to see that it is present.

  However, for such videos if I look at the relevant Media Foundation properties (Extended Color Information) the properties are not present in the files.

  So, somehow I need to find a way to access the information.

  Media Foundation does provide access to MF_MT_MPEG4_SAMPLE_DESCRIPTION and MF_MT_MPEG_SEQUENCE_HEADER for the video stream but I can’t find descriptions of what these contain.

  I noticed that the MF_MT_MPEG_SEQUENCE_HEADER is much longer for the videos with the information present and this (MPEG Headers Quick Reference) seems to suggest headers might contain the information I need.

  I’m looking for Color Range (limited/full), Color Primaries, Transfer Characteristics and Matrix Coefficients (BT.709 etc).

  I’d greatly appreciate any help finding this information from a Media Foundation video stream.

  Thanks

  Jules

  ---

  Update - Sequence Header

  The sequence header appears to be a subset of MPEG4 sample description, though I can’t find anything that indicates what either bits of data actually contains / doesn’t contain specifically.

  The sequence header appears to contain data structured as an MP4 byte stream as described in the H264 Standards Document and includes the VUI (Video Usability Information - Annex E of document) which may then include the colour information I’m interested in.

  Given that it’s a byte stream I need to know where it starts and whether there’s some existing code I could use to decode it.

  In FFMPEG in libavcodec/h264_ps.c there is a function called ff_h264_decode_seq_parameter_set which ends up calling decode_vui_parameters. It seems possible that seq_parameter_set maps to MF_MT_MPEG_SEQUENCE_HEADER and it may be possible to use that code to decode the data.

  If anyone one has any direct experience with decoding this data it would be very useful.

  Thanks again

  ---

  Update - Related posts

  I found this How to decode sprop-parameter-sets in a H264 SDP ? and Possible Locations for Sequence/Picture Parameter Set(s) for H.264 Stream which are fairly helpful.

  The sequence header would appear to be Sequence or picture parameter set (pps) and the parameters I want are the VUI extension subset.

  Plus this post H.264 stream structure gives the high level of how the stream data is structured, and the MF_MT_MPEG_SEQUENCE_HEADER appears to start with a NAL 0x00 0x00 0x01 so I’m guessing it is a NAL containing the PPS.

• Error decoding timecode using ffprobe

  16 novembre 2016, par Pablo Montilla

  I’m using ffprobe to get timecode from an mxf which has DF timecode but with a non DF frame rate. I’m getting the error Drop frame is only allowed with 30000/1001 or 60000/1001 FPS.

  I’m running ffprobe -i "IMX 10Bit.mxf" and getting the following :

    ffprobe version 3.2 Copyright (c) 2007-2016 the FFmpeg developers
  
      built with gcc 5.4.0 (GCC)
  
      configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
      libavutil      55. 34.100 / 55. 34.100
  
      libavcodec     57. 64.100 / 57. 64.100
  
      libavformat    57. 56.100 / 57. 56.100
  
      libavdevice    57.  1.100 / 57.  1.100
  
      libavfilter     6. 65.100 /  6. 65.100
  
      libswscale      4.  2.100 /  4.  2.100
  
      libswresample   2.  3.100 /  2.  3.100
  
      libpostproc    54.  1.100 / 54.  1.100
  
    [mxf @ 00000000025a3660] Drop frame is only allowed with 30000/1001 or 60000/1001 FPS
  
    Input #0, mxf, from 'IMX 10Bit.mxf':
  
      Metadata:
  
        uid             : 2b3801ea-ec5e-4dc1-ab3a-dba9a2b30ce4
  
        generation_uid  : 2b3801ea-ec5e-4dc2-ab3a-dba9a2b30ce4
  
        product_uid     : 00000000-0000-0000-0000-000000000000
  
        modification_date: 2009-11-04T10:39:42.000000Z
  
        material_package_umid: 0x060A2B340101010501010D43130000005C91020063D700800210F3FFFE154618
  
      Duration: 00:00:19.52, start: 0.000000, bitrate: 62580 kb/s
  
        Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, top first), 720x608 [SAR 152:135 DAR 4:3], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
        Metadata:
  
          file_package_umid: 0x060A2B340101010501010D43130000005D91020063D700800210F3FFFE154618
  
        Stream #0:1: Audio: pcm_s24le, 48000 Hz, 4 channels, s32 (24 bit), 4608 kb/s
  
        Metadata:
  
          file_package_umid: 0x060A2B340101010501010D43130000005D91020063D700800210F3FFFE154618