Signal processing in Chrome and Firefox

[moy...@agora-net.com]

We are working on a web based speech recording tool using getUserMedia with the requirement of using a recent version of Chrome or Firefox. When we first started it back in March things seemed to work well in both browsers, however over time it feels like more post-processing is being applied to the signal we're getting. For example on Monday we updated Firefox from a few versions back on a machine that was working well and now it is unusable. On the same machine Chrome used to work well but now gives fits. We are also seeing this behavior in other places.

It doesn't appear that the Javascript API available to the browsers has any hooks to get at disabling the AGC/AEC which I can see in the native WebRTC code.  Is there something I've missed, or is this just not supported at this time, or are there plans to add this in the future?

Let me know if any additional information would be helpful. Thanks.

[Vikas]

On Chrome you can use getUserMedia audio constraints to turn on and off AEC/AGC. You can take a look at some parameters that we use in apprtc demo here. Just try with googEchoCancellation and googAutoGainControl to tun on and off the AEC/AGC.

/Vikas

[moy...@agora-net.com]

Thanks, on the face of it this is exactly what we were looking for.  We are already having users work with reasonably good USB microphones in quiet, non-reverberant environments and need the cleanest (as in unprocessed) raw audio possible.

I had done quite a bit of grep'ing through both the Chrome and Firefox source but somehow didn't find these settings.  Does anyone know if there are similar controls for Firefox?