code: private void estimateJitter(RtpPacket packet) {
  		long transit = rtpClock.getLocalRtpTime() - packet.getTimestamp();
  		long d = transit - this.currentTransit;
  		this.currentTransit = transit;
  		
  		if(d < 0) {
  			d = -d;
  		}
  
  		this.jitter += d - ((this.jitter + 8) >> 4);
  	}
docs: Calculates interarrival jitter interval.
  
  <p>
  <code>
  int transit = arrival - r->ts;<br>
  int d = transit - s->transit;<br>
  s->transit = transit;<br>
  if (d < 0) d = -d;<br>
  s->jitter += (1./16.) * ((double)d - s->jitter);<br>
  </code>
  </p>
  
  @param packet
  @return
  @see <a
  href="http://tools.ietf.org/html/rfc3550#appendix-A.8">RFC3550</a>