code: synchronized public boolean addFrameThread(Frame frame) {
      FrameThread ft = new FrameThread(frame, this);
      inactiveFrameThreads.add(ft);
      boolean r = true;
      startFrameThreads();
      return r;
    }
docs: Add a Frame to this manager, which it will use to encode a block. Each
  Frame added allows one more thread to be used for encoding. At least one
  Frame must be added for this manager to encode.
  @param frame Frame to use for encoding.
  @return boolean false if there was an error adding the frame, true
  otherwise.