On 06/09/2014 05:30 PM, PE wrote:
2. Increase the ptime from 20 ms to 30-40 ms to reduce packet-drop exposure
Alex B may be right on this. Hard to speculate without hard evidence with lots of volume to back it up. I do know, however, that some carriers (Verizon comes to mind) will not support anything other than 20ms, so it is easier to standardize on a single ptime rather than try to customize each install.
Yeah, it's hard to say. There are lots of variables that could potentially pull this in different directions, and possibly still render it good advice. For instance, with fewer packets and a constant amount of packet loss, a small absolute number of packets get lost. and maybe that leads to more reasonable adaptive jitter buffer behaviour that introduces less perceived artifacts or loss into the speech path than does the loss of a larger amount of packets. Still, my instinct is that more packets with a smaller payload is better in a scenario with packet loss. It certainly seems that online games take this view as well, given the enormous amount of position updates that first-person shooters send, for instance. The idea is that even if some of them don't get there, all is not wholly lost. -- Alex Balashov - Principal Evariste Systems LLC Tel: +1-678-954-0670 Web: http://www.evaristesys.com/, http://www.alexbalashov.com/ Please be kind to the English language: http://www.entrepreneur.com/article/232906