Keep AVAudioPlayer sound in the memory

Question

I use AVAudioPlayer to play a click sound if the user taps on a button.

Because there is a delay between the tap and the sound, I play the sound once in viewDidAppear with volume = 0

I found that if the user taps on the button within a time period the sound plays immediately, but after a certain time there is a delay between the tap and the sound in this case also.

It seems like in the first case the sound comes from cache of the initial play, and in the second case the app has to load the sound again.

Therefore now I play the sound every 2 seconds with volume = 0 and when the user actually taps on the button the sound comes right away.

My question is there a better approach for this?

My goal would be to keep the sound in cache within the whole lifetime of the app.

Thank you,

Answer 1

To avoid audio lag, use the .prepareToPlay() method of AVAudioPlayer.

Apple's Documentation on Prepare To Play

Calling this method preloads buffers and acquires the audio hardware needed for playback, which minimizes the lag between calling the play() method and the start of sound output.

If player is declared as an AVAudioPlayer then player.prepareToPlay() can be called to avoid the audio lag. Example code:

struct AudioPlayerManager {

    var player: AVAudioPlayer? = AVAudioPlayer()

    mutating func setupPlayer(soundName: String, soundType: SoundType) {

    if let soundURL = Bundle.main.url(forResource: soundName, withExtension: soundType.rawValue) {
        do {
            player = try AVAudioPlayer(contentsOf: soundURL)
            player?.prepareToPlay()
        }
        catch  {
            print(error.localizedDescription)
        }
    } else {
        print("Sound file was missing, name is misspelled or wrong case.")
    }
}

Then play() can be called with minimal lag:

player?.play()