/// soundbanks are either dls or sf2. see http://www.sf2midi.com/
var soundbank:NSURL!
var mp:AVMIDIPlayer!

func playMIDIFile() {

        // Load a SoundFont or DLS file.
        self.soundbank = NSBundle.mainBundle().URLForResource("GeneralUser GS MuseScore v1.442", withExtension: "sf2")
        
        // a standard MIDI file.
        var contents:NSURL = NSBundle.mainBundle().URLForResource("ntbldmtn", withExtension: "mid")
        
        var error:NSError?
        self.mp = AVMIDIPlayer(contentsOfURL: contents, soundBankURL: soundbank, error: &error)
        if self.mp == nil {
            println("nil midi player")
        }
        if let e = error {
            println("Error \(e.localizedDescription)")
        }
        self.mp.prepareToPlay()
        
        self.mp.play(nil)
        
        // there is a crash when you use a completion 
        //self.mp.play({
        //    println("midi done")
        //})
        
  
        // or
//        var completion:AVMIDIPlayerCompletionHandler = {println("done")}
//        mp.play(completion)
        
    }

func toggleMIDIPlayer() {
        if mp.playing {
            mp.stop()
        } else {
            self.mp.play(nil)
        }
}
    
func stopMIDIPLayer() {
        if mp.playing {
            mp.stop()
        }
}