Swift：声音输出和麦克风输入 |使用 AudioKit |答案

【问题标题】：Swift: Sound-Output & Microphone-Input | using AudioKit |Swift：声音输出和麦克风输入 |使用 AudioKit |
【发布时间】：2018-01-06 18:21:56
【问题描述】：

我正在使用 >Xcode 9.2 版 我正在使用 >AudioKit 版本 4.0.4

我写了一些你可以在下面找到的代码

播放特定声音(frequency: 500.0HZ)
“监听”麦克风输入并实时计算频率

如果我调用playSound() 或receiveSound() 分开，一切看起来都很好，并且确实按我预期的那样工作。但是之后打电话给playSound() 和receiveSound()？正是在那里，我遇到了大问题。

这就是我想让代码工作的方式：

SystemClass.playSound() //play sound
DispatchQueue.main.asyncAfter(deadline: (DispatchTime.now() + 3.0)) {
   SystemClass.receiveSound() //get microphone input 3 seconds later
}

let SystemClass: System = System()
class System {
    public init() { }

    func playSound() {
        let sound = AKOscillator()
        AudioKit.output = sound
        AudioKit.start()
        sound.frequency = 500.0
        sound.amplitude = 0.5
        sound.start()
        DispatchQueue.main.asyncAfter(deadline: (DispatchTime.now() + 2.0)) {
            sound.stop()
        }
    }


    var tracker: AKFrequencyTracker!
    func receiveSound() {
        AudioKit.stop()
        AKSettings.audioInputEnabled = true
        let mic = AKMicrophone()
        tracker = AKFrequencyTracker(mic)
        let silence = AKBooster(tracker, gain: 0)
        AudioKit.output = silence
        AudioKit.start()
        Timer.scheduledTimer( timeInterval: 0.1, target: self, selector: #selector(SystemClass.outputFrequency), userInfo: nil, repeats: true)
    }

    @objc func outputFrequency() {
        print("Frequency: \(tracker.frequency)")
    }
}

这些消息是我每次想要运行代码时收到的一些编译器错误消息（调用 playSound() 并在 3 秒后调用 receiveSound ()）：

AVAEInternal.h:103:_AVAE_CheckNoErr: [AVAudioEngineGraph.mm:1266:Initialize: (err = AUGraphParser::InitializeActiveNodesInOutputChain(ThisGraph, kOutputChainOptimizedTraversal, *GetOutputNode(), isOutputChainActive)): error -10875

AVAudioEngine.mm:149:-[AVAudioEngine prepare]: Engine@0x1c401bff0: could not initialize, error = -10875

[MediaRemote] [AVOutputContext] WARNING: AVF context unavailable for sharedSystemAudioContext

[AVAudioEngineGraph.mm:1266:Initialize: (err = AUGraphParser::InitializeActiveNodesInOutputChain(ThisGraph, kOutputChainOptimizedTraversal, *GetOutputNode(), isOutputChainActive)): error -10875

Fatal error: AudioKit: Could not start engine. error: Error 

Domain=com.apple.coreaudio.avfaudio Code=-10875 "(null)" UserInfo={failed call=err = AUGraphParser::InitializeActiveNodesInOutputChain(ThisGraph, kOutputChainOptimizedTraversal, *GetOutputNode(), isOutputChainActive)}.: file /Users/megastep/src/ak/AudioKit/AudioKit/Common/Internals/AudioKit.swift, line 243

【问题讨论】：

标签： ios swift xcode audio audiokit

【解决方案1】：

我相信您的大部分问题是由于在使用它们的函数中本地声明 AKNodes：

   let sound = AKOscillator()
   let mic = AKMicrophone()        
   let silence = AKBooster(tracker, gain: 0)

将这些声明为实例变量，如here 所述。

【讨论】：

你能完成你在问题中写的（播放声音和接收声音）吗？我想做同样的事情，但它只是崩溃了。