Measure microphone level in WebRTC for iOS

Question

I have a WebRTC iOS application. There I have AVAudioSession and RTCAudioSource. I need to detect when a microphone starts receiving loud sounds (like when a person starts speaking) similar to what hark does in the browser with AudioContext. How can I detect it or get something that resembles stream that can be measured like AVCaptureAudioChannel or AVCaptureAudioDataOutput?

Answer 1

After using AVAudioSession to request permission to record audio, I would recommending using AVAudioRecorder. It is a fairly straightforward class and is as simple as:

• Create an instance of AVAudioRecorder
• Call the method prepareToRecord on the instance
• Enable the sound metering function using the method meteringEnabled

After enabling the recording, you can access the recording volume measurement using the method averagePowerForChannel:.

You may want to read Apple's documentation

~~~~~~~~~~~~~~~~~~~~~~~ N O T E ~~~~~~~~~~~~~~~~~~~~~~~

I am not familiar with the WebRTC framework/functionality, but the AVAudioRecorder class will provide you with the ability to measure the audio input during a recording.

~~~~~~~~~~~~~~~~~~~~~~ S A M P L E ~~~~~~~~~~~~~~~~~~~~~~

I've included a GitHub sample project that I've used in the past. It is setup to detect sensitivity of the audio using the AVAudioRecorder class that I've described.