ios - 重启录音时 AVAudioEngine inputNode installTap 崩溃

Question

我正在我的应用中实现语音识别。当我第一次向 View Controller 展示语音识别逻辑时，一切正常。但是，当我再次尝试呈现 View Controller 时，出现以下崩溃:

ERROR:    [0x190bf000] >avae> AVAudioNode.mm:568: CreateRecordingTap: required condition is false: IsFormatSampleRateAndChannelCountValid(format)
*** Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'required condition is false: IsFormatSampleRateAndChannelCountValid(format)'

下面是用于开始和停止录制的代码:

@available(iOS 10.0, *)
extension DictationViewController {

fileprivate func startRecording() throws {
    guard let recognizer = speechRecognizer else {
        debugLog(className, message: "Not supported for the device's locale")
        return
    }

    guard recognizer.isAvailable else {
        debugLog(className, message: "Recognizer is not available right now")
        return
    }

    mostRecentlyProcessedSegmentDuration = 0
    guard let node = audioEngine.inputNode else {
        debugLog(className, message: "Could not get an input node")
        return
    }

    let recordingFormat = node.outputFormat(forBus: 0)
    node.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { [weak self] (buffer, _) in
        self?.request.append(buffer)
    }

    audioEngine.prepare()
    try audioEngine.start()

    recognitionTask = recognizer.recognitionTask(with: request, resultHandler: {/***/})
}

fileprivate func stopRecording() {
    audioEngine.stop()
    audioEngine.inputNode?.removeTap(onBus: 0)
    request.endAudio()
    recognitionTask?.cancel()
}

}

startRecording() 在我们请求授权后在 viewDidLoad 中调用。 stopRecording() 在 View Controller 关闭时调用。

请协助。我正在努力寻找解决此崩溃的方法

Answer 1

首先，一个小问题。点击设备的麦克风时，您需要使用输入总线的格式:

let recordingFormat = node.inputFormat(forBus: 0)

其次，经过一些挖掘后，这个崩溃似乎最常见的原因是应用程序的共享 AVAudioSession 类别设置。如果您要执行实时麦克风音频处理，请确保您的 Audio Session 配置如下:

private func configureAudioSession() {
    do {
        try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayAndRecord, with: .mixWithOthers)
        try AVAudioSession.sharedInstance().setActive(true)
    } catch { }
}