ios - Get AVAudioPlayer to play multiple sounds at a time

Question

I'm trying to get multiple sounds files to play on an AVAudioPlayer instance, however when one sound plays, the other stops. I can't get more than one sound to play at a time. Here is my code:

import AVFoundation

class GSAudio{

    static var instance: GSAudio!

    var soundFileNameURL: NSURL = NSURL()
    var soundFileName = ""
    var soundPlay = AVAudioPlayer()

    func playSound (soundFile: String){

        GSAudio.instance = self

        soundFileName = soundFile
        soundFileNameURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource(soundFileName, ofType: "aif", inDirectory:"Sounds")!)
        do{
            try soundPlay = AVAudioPlayer(contentsOfURL: soundFileNameURL)
        } catch {
            print("Could not play sound file!")
        }

        soundPlay.prepareToPlay()
        soundPlay.play ()
    }
}

Can anyone please help me by telling me how to get more than one sound file to play at a time? Any help is much appreciated.

Many thanks, Kai

Answer 1

The reason the audio stops is because you only have one AVAudioPlayer set up, so when you ask the class to play another sound you are currently replacing the old instance with a new instance of AVAudioPlayer. You are overwriting it basically.

You can either create two instances of the GSAudio class, and then call playSound on each of them, or make the class a generic audio manager that uses a dictionary of audioPlayers.

I much prefer the latter option, as it allows for cleaner code and is also more efficient. You can check to see if you have already made a player for the sound before, rather than making a new player for example.

Anyways, I re-made your class for you so that it will play multiple sounds at once. It can also play the same sound over itself (it doesn't replace the previous instance of the sound) Hope it helps!

The class is a singleton, so to access the class use:

GSAudio.sharedInstance

for example, to play a sound you would call:

GSAudio.sharedInstance.playSound("AudioFileName")

and to play a number of sounds at once:

GSAudio.sharedInstance.playSounds("AudioFileName1", "AudioFileName2")

or you could load up the sounds in an array somewhere and call the playSounds function that accepts an array:

let sounds = ["AudioFileName1", "AudioFileName2"]
GSAudio.sharedInstance.playSounds(sounds)

I also added a playSounds function that allows you to delay each sound being played in a cascade kind of format. So:

 let soundFileNames = ["SoundFileName1", "SoundFileName2", "SoundFileName3"]
 GSAudio.sharedInstance.playSounds(soundFileNames, withDelay: 1.0)

would play sound2 a second after sound1, then sound3 would play a second after sound2 etc.

Here is the class:

class GSAudio: NSObject, AVAudioPlayerDelegate {

    static let sharedInstance = GSAudio()

    private override init() {}

    var players = [NSURL:AVAudioPlayer]()
    var duplicatePlayers = [AVAudioPlayer]()

    func playSound (soundFileName: String){

        let soundFileNameURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource(soundFileName, ofType: "aif", inDirectory:"Sounds")!)

        if let player = players[soundFileNameURL] { //player for sound has been found

            if player.playing == false { //player is not in use, so use that one
                player.prepareToPlay()
                player.play()

            } else { // player is in use, create a new, duplicate, player and use that instead

                let duplicatePlayer = try! AVAudioPlayer(contentsOfURL: soundFileNameURL)
                //use 'try!' because we know the URL worked before.

                duplicatePlayer.delegate = self
                //assign delegate for duplicatePlayer so delegate can remove the duplicate once it's stopped playing

                duplicatePlayers.append(duplicatePlayer)
                //add duplicate to array so it doesn't get removed from memory before finishing

                duplicatePlayer.prepareToPlay()
                duplicatePlayer.play()

            }
        } else { //player has not been found, create a new player with the URL if possible
            do{
                let player = try AVAudioPlayer(contentsOfURL: soundFileNameURL)
                players[soundFileNameURL] = player
                player.prepareToPlay()
                player.play()
            } catch {
                print("Could not play sound file!")
            }
        }
    }


    func playSounds(soundFileNames: [String]){

        for soundFileName in soundFileNames {
            playSound(soundFileName)
        }
    }

    func playSounds(soundFileNames: String...){
        for soundFileName in soundFileNames {
            playSound(soundFileName)
        }
    }

    func playSounds(soundFileNames: [String], withDelay: Double) { //withDelay is in seconds
        for (index, soundFileName) in soundFileNames.enumerate() {
            let delay = withDelay*Double(index)
            let _ = NSTimer.scheduledTimerWithTimeInterval(delay, target: self, selector: #selector(playSoundNotification(_:)), userInfo: ["fileName":soundFileName], repeats: false)
        }
    }

     func playSoundNotification(notification: NSNotification) {
        if let soundFileName = notification.userInfo?["fileName"] as? String {
             playSound(soundFileName)
         }
     }

     func audioPlayerDidFinishPlaying(player: AVAudioPlayer, successfully flag: Bool) {
        duplicatePlayers.removeAtIndex(duplicatePlayers.indexOf(player)!)
        //Remove the duplicate player once it is done
    }

}