#format wiki
#language en
= Notes on Voice over IP delay =
 * Goal <150ms oneway delay.
 * G.729 (CS-ACELP)
   * Total encoding delay 40 ms, 10 ms for Coder delay and 30 ms for Packetization delay. 
   * serialization delay of <4.75 ms (38bytes on 64kbit line) variable.
   * queuing delay behind other packets <10 ms (1024kbit or bigger line)
   * transmision delay estimated at 6 microseconds/km = 6ms/1000km
   * network provider delay 40ms + variable 25ms
   * de-jitter buffer is held for 40 ms 
   * TOTAL: '''100ms + Provider''' <== 40ms + 5ms + 10ms + 5ms + 40ms

 * '''multiple''' CS-ACELP '''compression cycles''' quickly introduce significant levels of distortion.
   * most users find that '''two compression cycles''' still provide '''adequate''' voice quality.

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