for (int i = 0; i < filterGraph.getNumTracks(); ++i)

    {

      if (filterGraph.isTrackEnabled(i))

      { 

        trackThreads[i] = new TrackThread(filterGraphCopy, i, videoTrackIndex == i ? FilterGraph.SUPPRESS_TRACK_READ : FilterGraph.PROCESS_DEFAULT); // use a copy of the graph for each thread, so that they don't interfere with each other.

       

        // mgodehardt: may block the blocking realize forever, if input stream is closed before data is read

        /*if (videoTrackIndex == i)  // if it has a video track - read the first video frame

        {  final int result = filterGraphCopy.process(null, videoTrackIndex, -1, FilterGraph.PROCESS_DEFAULT); // doesn't work because we have to use the actual filter graph clone that is used for the track.

     

      for (int i = 0; i < filterGraph.getNumTracks(); ++i)

      {

        if (filterGraph.isTrackEnabled(i))

          trackThreads[i] = new TrackThread(filterGraphCopy, i, FilterGraph.PROCESS_DEFAULT); // use a copy of the graph for each thread, so that they don't interfere with each other.

        }

      }

    }