性能方面，我是否应该使用 AVAudioEngine 来获得多种音效？

Question

Performance-wise, is it better to use an AVAudioPlayerNode instance with

A. one AVAudioEngine instance, to which I connect multiple sound effects to its mixer

B. a separate instance of AVAudioEngine for each sound effect?

The reason I'm using AVAudioEngine is because I'm doing some audio processing with AVAudioUnitVaryspeed, but each sound effect can be (and is) independent, so I was wondering if anyone knows what's best?

Is it OK to have an AVAudioEngine and its nodes for each effect or should I manage a single engine instance and connect / disconnect nodes as sounds play?

Answer 1

You should manage a single AVAudioEngine instance to which all your effects and player are connected, and connect/disconnect nodes as sounds play.

Having multiple AVAudioEngine instances isn't a problem because of the performance overhead, but because it'll become too complicated to manage them all in real time, having them all respond to AVAudioSession.routeChangeNotification and AVAudioSession.interruptionNotification , keeping all the players in sync, testing each one of them using renderOffline , and so on.

I recommend you watch WWDC 2014 Session 502 - AVAudioEngine in Practice, for a good introduction to this API. One of the use cases they bring up is very similar to yours – and they use just one AVAudioEngine instance:-)