I am trying to use the new AVAudioEngine in iOS 8.
It looks like the completionHandler of player.scheduleFile() is called before the sound file has finished playing.
I am using a sound file with a length of 5s -- and the println()
-Message appears round about 1 second before the end of the sound.
Am I doing something wrong or do I misunderstand the idea of a completionHandler?
Thanks!
Here is some code:
class SoundHandler {
let engine:AVAudioEngine
let player:AVAudioPlayerNode
let mainMixer:AVAudioMixerNode
init() {
engine = AVAudioEngine()
player = AVAudioPlayerNode()
engine.attachNode(player)
mainMixer = engine.mainMixerNode
var error:NSError?
if !engine.startAndReturnError(&error) {
if let e = error {
println("error \(e.localizedDescription)")
}
}
engine.connect(player, to: mainMixer, format: mainMixer.outputFormatForBus(0))
}
func playSound() {
var soundUrl = NSBundle.mainBundle().URLForResource("Test", withExtension: "m4a")
var soundFile = AVAudioFile(forReading: soundUrl, error: nil)
player.scheduleFile(soundFile, atTime: nil, completionHandler: { println("Finished!") })
player.play()
}
}
The AVAudioEngine docs from back in the iOS 8 days must have just been wrong. In the meantime, as a workaround, I noticed if you instead use scheduleBuffer:atTime:options:completionHandler:
the callback is fired as expected (after playback finishes).
Example code:
AVAudioFile *file = [[AVAudioFile alloc] initForReading:_fileURL commonFormat:AVAudioPCMFormatFloat32 interleaved:NO error:nil];
AVAudioPCMBuffer *buffer = [[AVAudioPCMBuffer alloc] initWithPCMFormat:file.processingFormat frameCapacity:(AVAudioFrameCount)file.length];
[file readIntoBuffer:buffer error:&error];
[_player scheduleBuffer:buffer atTime:nil options:AVAudioPlayerNodeBufferInterrupts completionHandler:^{
// reminder: we're not on the main thread in here
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(@"done playing, as expected!");
});
}];