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• To get OpenCV VideoWriter work across platforms consistently for MP4 container with H264 encoding

  28 mars 2019, par Moh

  I am trying to get OpenCV VideoWriter work across platform consistently for MP4 container with H246 encoding.

  Target platforms in order of importance - Ubuntu, Raspbian, OSX

  Basically, my shortcoming at this point is not understanding the relationship of FourCC code (as a parameter to OpenCV VideoWriter) to the FFMPEG backend and its requirements. I am interested to understand the game in play rather than discussing a piece of code.

  What I want to know is when I specify ’X264’ as FourCC code trying to write an x.MP4 file (FFMPEG backend) and the request is marshalled to FFMPEG what requirements/dependencies need to be satisfied by the OS for it to success.

  So far I have got my python stack writing MP4 video files across Raspbian/Ubuntu/OSX, with a hack.

  On my Raspbian stretch installation, I use 0x00000021 as the fourCC code.
  On Ubuntu (VM on OSX) and on OSX, AVC1 works.

  Days of Googling only delivered those hacks, not a good understanding of the problem.

  The x264 as FourCC code leads to one of - failure, non-portable video file + annoying FFMPEG warning.

  I am trying to get to the bottom of it.

  The code,

      #self.__fourCC = cv2.VideoWriter_fourcc('x', '2', '6', '4')
  
      self.__fourCC = cv2.VideoWriter_fourcc('a', 'v', 'c', '1')
  
      if PlatformUtils.isRunningOnRaspberryPi():
  
          self.__fourCC = 0x00000021

  I have control over the version both OpenCV and FFMPEG (if required GStreamer too). I can and have built them for Ubuntu/Raspbian.

• To get OpenCV VideoWriter work across platforms consistently for MP4 container with H264 encoding

  28 mars 2019, par Moh

  I am trying to get OpenCV VideoWriter work across platform consistently for MP4 container with H246 encoding.

  Target platforms in order of importance - Ubuntu, Raspbian, OSX

  Basically, my shortcoming at this point is not understanding the relationship of FourCC code (as a parameter to OpenCV VideoWriter) to the FFMPEG backend and its requirements. I am interested to understand the game in play rather than discussing a piece of code.

  What I want to know is when I specify ’X264’ as FourCC code trying to write an x.MP4 file (FFMPEG backend) and the request is marshalled to FFMPEG what requirements/dependencies need to be satisfied by the OS for it to success.

  So far I have got my python stack writing MP4 video files across Raspbian/Ubuntu/OSX, with a hack.

  On my Raspbian stretch installation, I use 0x00000021 as the fourCC code.
  On Ubuntu (VM on OSX) and on OSX, AVC1 works.

  Days of Googling only delivered those hacks, not a good understanding of the problem.

  The x264 as FourCC code leads to one of - failure, non-portable video file + annoying FFMPEG warning.

  I am trying to get to the bottom of it.

  The code,

      #self.__fourCC = cv2.VideoWriter_fourcc('x', '2', '6', '4')
  
      self.__fourCC = cv2.VideoWriter_fourcc('a', 'v', 'c', '1')
  
      if PlatformUtils.isRunningOnRaspberryPi():
  
          self.__fourCC = 0x00000021

  I have control over the version both OpenCV and FFMPEG (if required GStreamer too). I can and have built them for Ubuntu/Raspbian.

• Android - Decoding via a pipe will not work : Could not find an ffmpeg binary for your system

  28 août 2017, par Daniele

  I’m trying to use TarsosDSP for real time pitch shifting on Android.

  This is my code :

  Uri song;
  
  // initialized in another method
  
  
  
  double rate = 1.0;
  
          RateTransposer rateTransposer;
  
          AudioDispatcher dispatcher;
  
          WaveformSimilarityBasedOverlapAdd wsola;
  
  
  
          dispatcher = AudioDispatcherFactory.fromPipe(getRealPathFromUri(song), 44100, 5000, 2500);
  
          rateTransposer = new RateTransposer(rate);
  
          wsola = new WaveformSimilarityBasedOverlapAdd(WaveformSimilarityBasedOverlapAdd.Parameters
  
                  .musicDefaults(rate, 44100));
  
  
  
          wsola.setDispatcher(dispatcher);
  
          dispatcher.addAudioProcessor(wsola);
  
          dispatcher.addAudioProcessor(rateTransposer);
  
          dispatcher.addAudioProcessor(new AndroidAudioPlayer(dispatcher.getFormat()));
  
          dispatcher.setZeroPadFirstBuffer(true);
  
          dispatcher.setZeroPadLastBuffer(true);

  I get an error here

  dispatcher = AudioDispatcherFactory.fromPipe(getRealPathFromUri(song), 44100, 5000, 2500);

  Decoding via a pipe will not work : Could not find an ffmpeg binary for
  your system

  Why does this happen and how should I fix it ?

  EDIT :

  As far as I was able to understand it’s because ffmpeg isn’t integrated within the app. I looked for a guide here on SO but I couldn’t find any updated one. Using NDK r15c and FFmpeg 3.3.3