notes-phoneLatency

" The Results Doing this testing with a variety of cell phones on different carriers and traditional telecom landlines indicates that if you want to enjoy witty repartee with others, at least in San Francisco, you are much better going with Verizon than AT&T or T-Mobile. Verizon’s 1-way latency from our tests is about 280msecs, compared to 400-450msecs for AT&T and TMobile.

Skype, by comparison, generally outperforms the cell phones in terms of end-to-end latency: we measured audio delays of from 100-200msecs for various combinations of audio and video calls, where the two endpoints were on the same WiFi? network. So this means that with a packet delay of about 40 msecs (which is what we typically see when pinging Boston from San Francisco), a cross-country audio or even video call on Skype is going to come in with about 250msecs of delay and be a bit better than using a cell phone.

The Future On our own internal work on shared audio for High Fidelity, we’ve been able to get the audio delay down to about 75-90 msecs. We’ve also tested the experience quality of different amounts of audio delay, and found that less than 50 milliseconds is the point where when hearing one’s own voice the delay becomes imperceptible, and at less than 125 milliseconds or so the difference between the audio and video feeds of another person speaking usually becomes indistinguishable. " -- https://highfidelity.io/blog/