wrtc.getAudio is a boolean property controlling access to local microphone.
If wrtc.getAudio is false local microphone will not be used (calls will not transmit audio). As this property affects microphone usage it will affect all calls.
Boolean controlling access to local microphone:
true
wrtc.getAudio is usually set in wrtc.init(). If you for some reason want to change it later you need to call wrtc.changeMedia() after.