AVPlayer HLS live stream level meter (Display FFT Data)

Sadly, using an HLS stream with AVFoundation doesn't give you any control over the audio tracks. I ran into the same problem trying to mute an HLS stream, which turned out to be impossible.

The only way you could read audio data would be to tap into the AVAudioSession.

EDIT

You can access the AVAudioSession like this:

[AVAudioSession sharedInstance]

Here's the documentation for AVAudioSession

Measuring audio using AVPlayer looks to be an issue that is still ongoing. That being said, I believe that the solution can be reached by combining AVPlayer with AVAudioRecorder.

While the two classes have seemingly contradictory purposes, there is a work around that allows AVAudioRecorder to access the AVPlayer's audio output.

Player / Recorder

As described in this Stack Overflow Answer, recording the audio of a AVPlayer is possible if you access the audio route change using kAudioSessionProperty_AudioRouteChange.

Notice that the audio recording must be started after accessing the audio route change. Use the linked stack answer as a reference - it includes more details and necessary code.

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Once you have access to the AVPlayer's audio route and are recording, the measuring is relatively straightforward.

Audio Levels

In my answer to a stack question regarding measuring microphone input I describe the steps necessary to access the audio level measurements. Using AVAudioRecorder to monitor volume changes is more complex than one would think, so I included a GitHub project that acts as a template for monitoring audio changes while recording.

~~~~~~~~~~~~~~~~~~~~~~~~~~ Please Note ~~~~~~~~~~~~~~~~~~~~~~~~~~

This combination during an HLS live stream is not something that I have tested. This answer is strictly theoretical, so it may take a sound understanding of both classes to work out completely.