AVAudioPlayer causing SpriteNodes to jerk when animating - swift

Question

I am working on app atm where the user sees nodes animating across the screen. When the node passes a certain target area, the user must press a button and then a avplayer sound will play.
The problem is, anytime the user presses the button and the sound plays, the nodes all jerk and I have no idea why. To replicate the problem I am having, here is an example project I put together in few mins.
import SpriteKit
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let skView = self.view as! SKView
let scene = GameScene(size: CGSizeMake(self.view.frame.size.width, self.view.frame.size.height))
skView.presentScene(scene)
}
}
import SpriteKit
import AVFoundation
class GameScene: SKScene {
var buttonNode : SKSpriteNode?
override init(size: CGSize)
{
super.init(size: size)
self.backgroundColor = SKColor.whiteColor()
self.view?.backgroundColor = UIColor.whiteColor()
}
override func didMoveToView(view: SKView)
{
buttonNode = SKSpriteNode(imageNamed: "button")
buttonNode?.name = "button"
buttonNode?.position = CGPointMake(200, 200)
buttonNode?.size = CGSizeMake(150, 150)
self.addChild(buttonNode!)
NSTimer.scheduledTimerWithTimeInterval(1.5, target: self, selector: #selector(self.animateNodes), userInfo: nil, repeats: true)
}
var avPlayer : AVAudioPlayer?
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
for touch in touches
{
let viewTouchLocation = touch.locationInView(self.view)
let sceneTouchPoint = self.convertPointFromView(viewTouchLocation)
let touchedNode = self.nodeAtPoint(sceneTouchPoint)
if(touchedNode.name == "button")
{
let avURL = NSURL.fileURLWithPath(NSBundle.mainBundle().pathForResource("exampleSound", ofType: "wav")!)
avPlayer = try? AVAudioPlayer(contentsOfURL: avURL)
avPlayer?.volume = 0.2
avPlayer?.play()
}
}
}
func animateNodes()
{
let sprite = SKSpriteNode(imageNamed: "shortMetalWhite")
sprite.color = UIColor.blackColor()
sprite.colorBlendFactor = 1.0
sprite.position = CGPointMake(self.view!.frame.size.width, 400)
self.addChild(sprite)
let noteDuration = 4.0
let actionMove = SKAction.moveTo(CGPointMake(-5, 400), duration: noteDuration)
let actionMoveDone = SKAction.removeFromParent()
sprite.runAction(SKAction.sequence([actionMove, actionMoveDone]))
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Does anyone have any idea what causes this? Is there something wrong with sprite nodes and avplayer that causes this? I have replicated this same code in a non game app, where you have a series of UIViews animating across the screen and a sound plays everytime you press a button and there is no issue with any lag or jerkiness. So what is it about sprite nodes and AVPlayer that causes this issue?
(Btw the issue is not as noticeable on the simulator, but when you run it on any iPhone or iPad, it is very noticeable)
Any help would be much appreciated
Edit:
If I swap to using AudioServices instead like this
if let soundURL = NSBundle.mainBundle().URLForResource("OHH10 Drums1DOTcom", withExtension: "wav") {
var mySound: SystemSoundID = 0
AudioServicesCreateSystemSoundID(soundURL, &mySound)
// Play
AudioServicesPlaySystemSound(mySound);
}
there is no lag, but then I have no control over the volume. So not an ideal solution

Answer 1

After doing more research, it seems its an issue with AVAudioPlayer, it is not really suited for playing repeating sounds effects in short succession.
So instead I swapped to using
SKAction.playSoundFileNamed("example.wav", waitForCompletion: false)
Again issue with this is that it does not allow you to control the volume. This means I had to open up audacity and modify the volume of each sound file to get it just right.
I would have preferred a better solution, but sadly this is the best I can find if I want to avoid any game lag