Why AVAudioPlayer always shows -160 dB averagePower level

Question

I have AVAudioPlayer initialized in my macOS app like below:

do {
    let audioFile = Bundle.main.path(forResource: "sample", ofType: "mp3")!
    let audioURL = URL(filePath: audioFile)
    player = try AVAudioPlayer(contentsOf: audioURL)
} catch {
    fatalError()
}

When I click the "Start" button it starts to play sound correctly but the printed dBLevel is always -160.

Button("Start") {
    player!.play()
    var dbLevel = Float(0)
    timer = Timer.scheduledTimer(withTimeInterval: 0.2, repeats: true, block: { _ in
        player!.updateMeters()
        dbLevel = 0
        for n in 0..<player!.numberOfChannels {
            dbLevel += player!.averagePower(forChannel: n)
        }
        dbLevel = dbLevel / Float(player!.numberOfChannels)
        print(dbLevel)
    })
}

Note that Xcode writes the following message to the console

AddInstanceForFactory: No factory registered for id <CFUUID 0x600002d8d0e0>...

What I'm doing wrong?

Answer 1

I found the solution quickly - this line was needed:

 player!.isMeteringEnabled = true