您正在设置 InputCallback 和 RenderCallback 方法不正确。其他设置似乎没问题。所以你的 init 方法应该是这样的。

You are setting the InputCallback and RenderCallback method incorrectly. Other settings seems OK. So your init method should be like this.

init() {

    var status: OSStatus

    do {
        try AVAudioSession.sharedInstance().setPreferredIOBufferDuration(preferredIOBufferDuration)
    } catch let error as NSError {
        print(error)
    }


    var desc: AudioComponentDescription = AudioComponentDescription()
    desc.componentType = kAudioUnitType_Output
    desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO
    desc.componentFlags = 0
    desc.componentFlagsMask = 0
    desc.componentManufacturer = kAudioUnitManufacturer_Apple

    let inputComponent: AudioComponent = AudioComponentFindNext(nil, &desc)

    status = AudioComponentInstanceNew(inputComponent, &audioUnit)
    checkStatus(status)

    var flag = UInt32(1)
    status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, kInputBus, &flag, UInt32(sizeof(UInt32)))
    checkStatus(status)

    status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, kOutputBus, &flag, UInt32(sizeof(UInt32)))
    checkStatus(status)

    var audioFormat: AudioStreamBasicDescription! = AudioStreamBasicDescription()
    audioFormat.mSampleRate = 8000
    audioFormat.mFormatID = kAudioFormatLinearPCM
    audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked
    audioFormat.mFramesPerPacket = 1
    audioFormat.mChannelsPerFrame = 1
    audioFormat.mBitsPerChannel = 16
    audioFormat.mBytesPerPacket = 2
    audioFormat.mBytesPerFrame = 2

    status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, kInputBus, &audioFormat, UInt32(sizeof(UInt32)))
    checkStatus(status)


    try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayAndRecord)
    status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, kOutputBus, &audioFormat, UInt32(sizeof(UInt32)))
    checkStatus(status)


    // Set input/recording callback
    var inputCallbackStruct = AURenderCallbackStruct(inputProc: recordingCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
    AudioUnitSetProperty(audioUnit, AudioUnitPropertyID(kAudioOutputUnitProperty_SetInputCallback), AudioUnitScope(kAudioUnitScope_Global), 1, &inputCallbackStruct, UInt32(sizeof(AURenderCallbackStruct)))


    // Set output/renderar/playback callback
    var renderCallbackStruct = AURenderCallbackStruct(inputProc: playbackCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
    AudioUnitSetProperty(audioUnit, AudioUnitPropertyID(kAudioUnitProperty_SetRenderCallback), AudioUnitScope(kAudioUnitScope_Global), 0, &renderCallbackStruct, UInt32(sizeof(AURenderCallbackStruct)))


    flag = 0
    status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_ShouldAllocateBuffer, kAudioUnitScope_Output, kInputBus, &flag, UInt32(sizeof(UInt32)))
}

尝试使用此代码如果有帮助，请告诉我们。

Try with this code and let us know if that helps.