Swift：在后台播放音频时识别来自麦克风的语音

Question

我希望我的应用能够识别来自麦克风的语音并允许后台音频继续播放。

我的应用程序识别通过麦克风传入的语音并将其转换为文本。当我的应用程序启动时，它会关闭后台播放的所有音频。

当我的应用程序使用麦克风收听语音时，是否可以让背景音频继续播放？

精简代码：

导入 UIKit 导入语音 类 ViewController: UIViewController { 公共私人（设置）var isRecording = false 私人变种音频引擎：AVAudioEngine！ 私人变种输入节点：AVAudioInputNode！ 私有 var audioSession：AVAudioSession！ 私有 var recognitionRequest：SFSpeechAudioBufferRecognitionRequest？

override func viewDidLoad() {
    super.viewDidLoad()
}

override public func viewDidAppear(_ animated: Bool) {
    checkPermissions()
    startRecording()
    isRecording.toggle()
}

private func startRecording() {

    guard let recognizer = SFSpeechRecognizer(), recognizer.isAvailable else {
        handleError(withMessage: "Speech recognizer not available.")
        return
    }
    recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
    recognitionRequest!.shouldReportPartialResults = true
    recognizer.recognitionTask(with: recognitionRequest!) { (result, error) in
        guard error == nil else { self.handleError(withMessage: error!.localizedDescription); return }
        guard let result = result else { return }
        print(result.bestTranscription.segments)
    }
    audioEngine = AVAudioEngine()
    inputNode = audioEngine.inputNode
    let recordingFormat = inputNode.outputFormat(forBus: 0)
    inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, _) in
        self.recognitionRequest?.append(buffer)
    }
    audioEngine.prepare()

    do {
        audioSession = AVAudioSession.sharedInstance()
        try audioSession.setCategory(.record, mode: .spokenAudio, options: .duckOthers)
        try audioSession.setActive(true, options: .notifyOthersOnDeactivation)
        try audioEngine.start()
    } catch {
        handleError(withMessage: error.localizedDescription)
    }
}
private func checkPermissions() {
    SFSpeechRecognizer.requestAuthorization { authStatus in
        DispatchQueue.main.async {
            switch authStatus {
            case .authorized: break
            default: self.handlePermissionFailed()
            }
        }
    }
}

private func handlePermissionFailed() {
    // Present an alert asking the user to change their settings.
    let ac = UIAlertController(title: "This app must have access to speech recognition to work.",
                               message: "Please consider updating your settings.",
                               preferredStyle: .alert)
    ac.addAction(UIAlertAction(title: "Open settings", style: .default) { _ in
        let url = URL(string: UIApplication.openSettingsURLString)!
        UIApplication.shared.open(url)
    })
    ac.addAction(UIAlertAction(title: "Close", style: .cancel))
    present(ac, animated: true)
}
private func handleError(withMessage message: String) {
    // Present an alert.
    let ac = UIAlertController(title: "An error occured", message: message, preferredStyle: .alert)
    ac.addAction(UIAlertAction(title: "OK", style: .default))
    present(ac, animated: true)
}

}

当您运行我的应用程序并且有音频在后台运行时，我的应用程序会暂停音频。我尝试退出我的应用程序并重新启动音频，但是当我返回我的应用程序时，它再次暂停背景音频。我希望在我的应用程序使用麦克风收听时继续播放音频。

我尝试删除“选项：.duckOthers”，但没有任何区别。

我相信我想做的事是可能的。例如，Shazam 可以在扬声器上播放歌曲，同时使用麦克风收听并识别歌曲。

Answer 1

试试 .playAndRecord 而不是 .record 。