Codec Delay

mcross · ‎03-08-2008

For G.729 10ms of voice is encoded plus another 5ms look ahead. This is where I get a little confused. The 5ms of look ahead also shows 5ms of delay to process the 5ms of look-ahead. This looks like 20ms of actual dealy...10ms for the original 10ms of voice to be received plus 5ms of look ahead plus 5ms of processing time equalling 20ms of total codec delay. Please confirm this or show me my flaw.

paolo bevilacqua · ‎03-09-2008

This is the best document you can reference:

http://cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml

Any doubt, please mention the exact section of the above that you've questions about.

Hope this helps, please rate post if it does!

mcross · ‎03-10-2008

Thank you for the reference. I actually had pulled it from a note in the Cisco QoS book. My confusion is with Algorithmic Delay. In the white paper it only references the 5ms look-ahead delay. In the QoS book it references the 5 ms look-ahead delay + 5 ms processing = 10 ms. I am hung up on the 5 ms processing delay. Will this make the actual delay 20 ms instead of 15 ms?