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• FFmpeg and Android encoding issue

  4 décembre 2012, par brux

  I compiled ffmpeg for Android. The executable works from the device terminal and I can do normal video operations. I am trying to join 2 mpeg files captured using the camera at the command line on the device.

  First I Capture 2 videos using the camera and save to sdcard, one.mpeg and two.mpeg. Then I do :

   ffmpeg -i one.mpeg onenew.mpeg
  
   ffmpeg -i twompg.mpeg twonew.mpeg 

  (if i dont do the above 2 commands then it doesnt work at all)

   cat onenew.mpeg twonew.mpeg > joined.mpeg
  
   ffmpeg -i joined.mpeg -acodec copy -vcodec copy final.mpeg

  The output (final.mpeg) doesnt play on the device but if i copy to my linux desktop it opens up and plays fine. I tested final.mpeg on a 2.3.3 device and a 2.3.6 device.

  Anyone know why the device would fail to play the video file ?

  UPDATE
  My friend tested the video on a device running 3.0, the default player never played the video however 'moboplayer' did, I need it to play on the default player though.

• FFmpeg insufficient thread locking only when deploying application using homebrew

  20 décembre 2012, par Kikohs

  I have the strangest bug of my life.
  I have installed ffmpeg using homebrew. I use it from a dll.
  I have set a lock manager because I use ffmpeg from multiple threads.

  In Engine.h :

  class EXPORT_LIB Engine
  
  {
  
  public:
  
      static int initEngine();    
  
      static int closeEngine();
  
  };

  In Engine.cpp :

  static int ff_lockmgr(void **mutex, enum AVLockOp op)
  
  {
  
  if (NULL == mutex)
  
      return -1;
  
  
  
  switch(op)
  
  {
  
  case AV_LOCK_CREATE:
  
  {
  
      *mutex = NULL;
  
      boost::mutex * m = new boost::mutex();
  
      *mutex = static_cast(m);
  
      break;
  
  }
  
  case AV_LOCK_OBTAIN:
  
  {
  
      boost::mutex * m =  static_cast(*mutex);
  
      m->lock();
  
      break;
  
  }
  
  case AV_LOCK_RELEASE:
  
  {
  
      boost::mutex * m = static_cast(*mutex);
  
      m->unlock();
  
      break;
  
  }
  
  case AV_LOCK_DESTROY:
  
  {
  
      boost::mutex * m = static_cast(*mutex);
  
      delete m;
  
      break;
  
  }
  
  default:
  
      break;
  
  }
  
  return 0;
  
  }
  
  
  
  
  
  int Engine::initEngine()
  
  {
  
      int res = -1;
  
      res = av_lockmgr_register(&ff_lockmgr);
  
      av_register_all();
  
      av_log_set_level(AV_LOG_QUIET); // ERROR, PANIC
  
      // Av lock manager success
  
      if( res == 0 ) {
  
          res = MULTITHREAD;
  
      }
  
      else {
  
          res = SINGLETHREAD;
  
      }
  
      return res;
  
  }
  
  
  
  int Engine::closeEngine()
  
  {
  
      int res = 0;
  
      res = av_lockmgr_register(NULL);
  
      return res;
  
  }

  So far so good, everything works as expected.

  When I deploy my app using CMake fix_bundle. I have an error message

  insufficient thread locking around avcodec_open/close()

  If I compile ffmpeg by hand in a custom location, when I deploy the app everything works as expected. What is wrong with homebrew ?

• Processing .Raw images using ffmpeg or OpenCV

  23 février 2013, par Ahmed Kato

  After reading Wikipedia page of Raw image format which is the digital negative of any image.

  To be viewed or printed, the output from a camera's image sensor has
  to be processed, that is, converted to a photographic rendering of the
  scene, and then stored in a standard raster graphics format such as
  JPEG. This processing, whether done in-camera or later in a raw-file
  converter, involves a number of operations, typically including

  I have some .raw files grabbed from my Logitech c920 using v4l2 example but when I display the image it looks like this :
  a raw image where in other frames I can see my shadow

  Does anyone knows how to process such files to see the complete frame ?

  Here is a link to the original .raw file