RTCAudioHandlerStats: Signal/Noise Ratio

[aboba]

Currently in RTCAudioHandlerStats we have audioLevel and totalAudioEnergy, but no estimate of the level of noise and signal. In Edge, we collect the following stats: https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#msaudiorecvsignal*

[vr000m]

@aboba @henbos Since MS/Edge and Google/Chrome have implementations of the audio stack, could someone from your team take a first stab at proposals for this?

I am happy to review.

[alvestrand]

Do we have a definition of SNR that people can turn into code?

[aboba]

Edge provides the following tap points:

• Signal levels as captured from the mic (pre AEC or any other processing such as AGC)
• Signal levels post WebRTC DSP such as AEC
• Signal levels post NetEQ on the render side
• Signal levels post any signal processing such as AGC or DRC on the render path

Perhaps these metrics would better be added to RTCAudioSenderStats?

[henbos]

If we had the background audio level, could a meaningful "signal/noise ratio" be derived by dividing signal audio level (total - background noise level) by total audio level?

[henbos]

Removing TPAC label for the same reason as described here.