How to loop background music without lag/delay when song repeats (seamless) - swift

Question

I am trying to make a game with background music looping in it. I made the song file in Adobe Audition (which is similar to audacity) and when I play it in a loop in Adobe Audition it loops how I want it.
When I play it in Xcode however, it has a lag in between the loops. I am using AVFoundations for the sound playing.
I have searched everywhere but I can't find the solution for the problem.
Is there any way you can loop audio files without there being any lags in between ? (I believe its called "seamless looping" )
here is the code:
class GameScene: SKScene {
...// Other Code
var ButtonAudio = URL(fileURLWithPath: Bundle.main.path(forResource: "Gamescene(new)", ofType: "mp3")!)
var ButtonAudioPlayer = AVAudioPlayer()
... //Other Code
}
And When I Call it:
override func didMove(to view: SKView) {
...//Code
ButtonAudioPlayer = try! AVAudioPlayer(contentsOf: ButtonAudio, fileTypeHint: nil)
ButtonAudioPlayer.numberOfLoops = -1
ButtonAudioPlayer.prepareToPlay()
ButtonAudioPlayer.play()
...//More Code
}
Can someone help me with this issue ?
Thank you in advance!

Answer 1

You can use AVPlayerLooper and AVQueuePlayer to do this.
import UIKit
import AVFoundation
class ViewController: UIViewController {
var queuePlayer = AVQueuePlayer()
var playerLooper: AVPlayerLooper?
override func viewDidLoad() {
super.viewDidLoad()
guard let url = Bundle.main.url(forResource: "Gamescene(new)", withExtension: "mp3") else { return }
let playerItem = AVPlayerItem(asset: AVAsset(url: url))
playerLooper = AVPlayerLooper(player: queuePlayer, templateItem: playerItem)
queuePlayer.play()
}
}

Answer 2

The solution proposed by #dave234 only works in iOS > 10. Since I needed to make seamless playback in iOS > 9, I did something different:
Instead of AVPlayer, I created AVQueuePlayer and immediately added two identical melodies to the queue.
Next, I made a listener to the penultimate melody.
When the listener was triggered, I added another similar record to the queue after the last one.
In fact, in order to avoid delay, I always play the penultimate record.
My code:
var player: AVQueuePlayer?
override func viewDidLoad() {
super.viewDidLoad()
if let path = Bundle.main.path(forResource: "music_file", ofType: "mp3") {
player = createPlayer(url: URL(fileURLWithPath: path))
}
}
func createPlayer(url: URL) -> AVQueuePlayer {
let player = AVQueuePlayer(items: [AVPlayerItem(url: url), AVPlayerItem(url: url)])
loopPlayer(playerItem: player.items()[player.items().count - 2])
return player
}
func loopPlayer(playerItem: AVPlayerItem) {
NotificationCenter.default.addObserver(forName: .AVPlayerItemDidPlayToEndTime, object: playerItem, queue: .main) { _ in
if let player = self.player, let url = (playerItem.asset as? AVURLAsset)?.url {
player.insert(AVPlayerItem(url: url), after: player.items()[player.items().count - 1])
self.loopPlayer(playerItem: player.items()[player.items().count - 2])
}
}
}