webrtc audio_processing: what is keyboard channel in StreamConfig?

Question

At webrtc/modules/audio_processing/include/audio_processing.h class StreamConfig there is an option has_keyboard, my question is what it is? and How to use it?

Answer 1

That's the keyboard microphone channel and by default it will be used if the user's keyboard has a microphone.

If you look at helpers.cc:

webrtc::StreamConfig CreateStreamConfig(const AudioParameters& parameters) {
  int channels = parameters.channels();
  (...)
  const bool has_keyboard = parameters.channel_layout() ==
                            media::CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC;