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• OpenCV 3.0.0 make error with FFMPEG

  24 mars 2016, par Ujjwal Aryan

  I have been using OpenCV for a while. However I have recently changed my system to a cluster where I do not have any admin permission. The problem is like this :

  In my home folder, I installed FFMPEG (latest stable version available on ffmpeg site). I installed it in $HOME, and so in $HOME/lib there are the library files installed. For more information I compiled FFMPEG with following options :

  ./configure --prefix=$HOME --enable-shared --enable-pic

  I then downloaded the latest stable version of OpenCV 3.0.0 and configured it using ccmake. When I try to make -j8, it gives me the following error.

   Scanning dependencies of target opencv_videoio
  
  [ 63%] [ 63%] [ 63%] [ 63%] [ 63%] [ 63%] Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_mjpeg_decoder.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_images.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_v4l.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_mjpeg_encoder.cpp.o
  
  Building CXX object modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o
  
  In file included from /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg.cpp:45:0:
  
  /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg_impl.hpp:1546:71: error: use of enum 'AVCodecID' without previous declaration
  
  /home/uujjwal/libraries/opencv-nogpu/opencv-3.0.0/modules/videoio/src/cap_ffmpeg_impl.hpp:1556:83: error: use of enum 'AVCodecID' without previous declaration
  
  make[2]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/src/cap_ffmpeg.cpp.o] Error 1
  
  make[2]: *** Waiting for unfinished jobs....

  However without ffmpeg support it works fine. However I need ffmpeg support due to the nature of my work.

  In trying to resolve the problem, I tried installing OpenCV 2.4.11 but it also gave this error. The latest GIT version does not give me this error but rather an error a part of which goes like this

  Linking CXX shared library ../../lib/libopencv_highgui.so /usr/bin/ld: /home/matheus/ffmpeg_build/lib/../lib/libavcodec.a(avpacket.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used

  I have pasted the above error from another unresolved question online and so the folder names are different but the relocation error is exactly the same.

  In trying to resolve the problem I searched and found the following link http://answers.opencv.org/question/12597/build-problems-for-opencv-241-with-ubuntu-1204-lts/

  However, one of the answers over there mentioned changing some lines in cap_ffmpeg_impl.hpp file. I tried doing that but either i am not able to do it correctly or something else is going wrong and it is not working. Exact line numbers and exact changes are not mentioned and so I am having difficulty changing things and being sure.

  I am using Fedora 19 (Schrodinger Cat) as the operating system I hope the details of my question are clear and I hope that the community would oblige me with a good response.

  Regards
  Ujjwal

• Extract every audio and subtitles from a video with ffmpeg

  4 octobre 2015, par WhatWhereWhen

  I have multiple audio tracks and subtitles to extract in a single .mkv file. I’m new to ffmpeg commands, this is what I’ve tried (audio) :

  ffmpeg -i VIDEO.mkv -vn -acodec copy AUDIO.aac

  It just extract 1 audio. What I want is tell ffmpeg to extract every single audio files and subtitle files to a destination, and keep the original name of each files and extensions. (Because I don’t know which extension does the audio files are, sometimes maybe .flac or .aac).

  I’m not sure about the solutions I’d found online, because it’s quite complicated, and I need explanations to know how it’s works, so that I can manipulate the command in the future. By the way, I planned to run the code from Windows CMD.

  Thanks.

• ffprobe returns mov,mp4,m4a,3gp,3g2,mj2

  19 octobre 2015, par sathia

  I’m trying to find a certain way to understand if a given file is using the h.264 codec and it’s streamable.

  I’m using ffprobe and sometimes I get output such as this :

  {
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'file.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 2036-02-06 06:28:16
  
      encoder         : HandBrake 0.10.2 2015060900
  
    Duration: 00:06:42.13, start: 0.000000, bitrate: 950 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709), 640x480 [SAR 1:1 DAR 4:3], 788 kb/s, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
  
      Metadata:
  
        creation_time   : 2036-02-06 06:28:16
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 155 kb/s (default)
  
      Metadata:
  
        creation_time   : 2036-02-06 06:28:16
  
        handler_name    : Stereo
  
      "format": {
  
          "filename": "file.mp4",
  
          "nb_streams": 2,
  
          "nb_programs": 0,
  
          "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
  
          "format_long_name": "QuickTime / MOV",
  
          "start_time": "0.000000",
  
          "duration": "402.134000",
  
          "size": "47787790",
  
          "bit_rate": "950683",
  
          "probe_score": 100,
  
          "tags": {
  
              "major_brand": "mp42",
  
              "minor_version": "512",
  
              "compatible_brands": "isomiso2avc1mp41",
  
              "creation_time": "2036-02-06 06:28:16",
  
              "encoder": "HandBrake 0.10.2 2015060900"
  
          }
  
      }
  
  }

  now, it seems that the file is streamable and it’s ok to be put online, but I was expecting something like this :

      "format_name": "h.264",

  instead I get

      "format_name": "mov,mp4,m4a,3gp,3g2,mj2",

  which seems very lax in terms of specifying what the hell this file is.
  I’m also using MP4Box in order to see if the video is streamable, but at this point I’m not sure how to handle specific h.264 recognition.

  what should I do in order to be sure that a given file has the h.264 codec ?

  thanks