Re: currentTime reporting, Chromium on Android [via Multi-device Timing Community Group]

Hello,

While I mainly work with the Web Audio API (with a slightly different 
definition of currentTime), the topic is close, so I give you my 
experience, with an other synchronisation solution (using only the Web 
Audio API).

We noticed that it was not enough to measure the clock, but it was 
important to us to record the resulting audio with a single multi-track 
recorder, in order to accurately compare the synchronisation of the 
devices. In addition to the synchronisation of the clocks, we had to 
calibrate the extra audio latency inherent to the various devices. 
Still, there is some jitter in the audio, that depend on the device (1 
to 5 ms around the reference).

We also collected time-stamps, and we found out that providing 
conversion functions between the reference clock and the local clock was 
good to avoid loosing time between reading the time and scheduling an 
event: (It is good that a clock always advance, so you can read an 
actual time when you need it. Otherwise, you can keep it.)

const now = getReferenceTime();  // no value: get current time
const local = getLocalTime(now); // value: convert
value1.setValueAtTime(local);
value1.setValueAtTime(local + 1);

Best,

Jean-Philippe

Received on Wednesday, 9 March 2016 08:12:38 UTC