Swift 2 - m4a file won't play on iOS

Question

I'm trying to play an m4a file on an iOS device programatically. The file is downloaded from a server and stored. When the user presses a button, it is played. The file, when copied from the device to OSX does play fine. I am using the code

var player:AVAudioPlayer = AVAudioPlayer()

func playAudio(sender: UIButton!) {
    let audioPath = FileUtils.getPath(audioPaths[sender.tag])
    print("PATH " + audioPath)//The printed path IS DEFINETLY correct
    do{
        player = try! AVAudioPlayer(contentsOfURL: NSURL(fileURLWithPath: audioPath))
        player.prepareToPlay()
        player.play()
    }
}

The path is correct so I'm not sure why it won't work. Could it be the format (even though it plays on OSX)?

An example file: https://www.dropbox.com/s/csewwg6n9vzan5z/131015-08%3A13%3A30.m4a?dl=0

Answer 1

That file won't play on iOS because it's encoded in AMR NarrowBand, which is no longer supported.

I would try re-encoding the m4a files as AAC, or switch to mp3.