如何使用Swift在iOS中同时录制和播放音频？

Question

在Objective-C中，同时录制和播放音频相当简单。互联网上有大量示例代码。但是我想使用 Audio Unit/Core Audio in Swift 同时录制和播放音频。使用 Swift 对此几乎没有帮助和示例代码。而且我找不到任何可以说明如何实现这一目标的帮助。

我正在努力处理以下代码。

let preferredIOBufferDuration = 0.005 
let kInputBus  = AudioUnitElement(1)
let kOutputBus = AudioUnitElement(0)

init() {
    // This is my Audio Unit settings code.
    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! = AURenderCallbackStruct(inputProc: recordingCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
    inputCallbackStruct.inputProc = recordingCallback
    inputCallbackStruct.inputProcRefCon = UnsafeMutablePointer(unsafeAddressOf(self))
    status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, kInputBus, &inputCallbackStruct, UInt32(sizeof(UInt32)))
    checkStatus(status)


    // Set output/renderar/playback callback
    var renderCallbackStruct: AURenderCallbackStruct! = AURenderCallbackStruct(inputProc: playbackCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
    renderCallbackStruct.inputProc = playbackCallback
    renderCallbackStruct.inputProcRefCon = UnsafeMutablePointer(unsafeAddressOf(self))
    status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Global, kOutputBus, &renderCallbackStruct, UInt32(sizeof(UInt32)))
    checkStatus(status)


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


func recordingCallback(inRefCon: UnsafeMutablePointer<Void>,
                      ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>,
                      inTimeStamp: UnsafePointer<AudioTimeStamp>,
                      inBufNumber: UInt32,
                      inNumberFrames: UInt32,
                      ioData: UnsafeMutablePointer<AudioBufferList>) -> OSStatus {

    print("recordingCallback got fired  >>>")


    return noErr
}



func playbackCallback(inRefCon: UnsafeMutablePointer<Void>,
                      ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>,
                      inTimeStamp: UnsafePointer<AudioTimeStamp>,
                      inBufNumber: UInt32,
                      inNumberFrames: UInt32,
                      ioData: UnsafeMutablePointer<AudioBufferList>) -> OSStatus {

    print("playbackCallback got fired  <<<")


    return noErr
}

使用该代码，只会调用 recordingCallback 方法。 playbackCallback 方法根本没有被触发。我确定我在这里出错了。有人可以帮我解决这个问题吗？我正在为这个问题苦恼。

Answer 1

您设置的 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。

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)))
}

试试这个代码，如果有帮助请告诉我们。

如何使用Swift在iOS中同时录制和播放音频？

How to record and play audio simultaneously in iOS using Swift?

core-audio

audiounit

ios

swift

swift2