code: public void readRegionToBuff(int off, int len, byte[] outBuff) {
  		assert off >= 0;
  		assert len > 0;
  		assert outBuff != null;
  		assert outBuff.length >= len;
  		assert buffer.limit() >= off + len;
  
  		buffer.position(off);
  		buffer.get(outBuff, 0, len);
  	}
docs: Read a byte region from specified offset in the RTP packet and with
  specified length into a given buffer
  
  @param off
  start offset in the RTP packet of the region to be read
  @param len
  length of the region to be read
  @param outBuff
  output buffer