ios - 静默 X 秒后停止录音

Question

我正在实现以下教程:Speech To Text

我正在使用 AVAudioEngine 和 SFSpeechRecognizer 录制音频实现语音到文本。此处教程使用以下方法将语音引导至文本一个开始和停止录制的按钮。

当应用程序获得允许。但是几秒钟后我找不到任何停止录制的方法沉默。以下是我的代码:

import UIKit
import Speech

public class ViewController: UIViewController, SFSpeechRecognizerDelegate {
// MARK: Properties

private let speechRecognizer = SFSpeechRecognizer(locale: Locale(identifier: "en-US"))!

private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest?

private var recognitionTask: SFSpeechRecognitionTask?

private let audioEngine = AVAudioEngine()

@IBOutlet var textView : UILabel!

@IBOutlet var recordButton : UIButton!


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

    recordButton.isEnabled = false
}

override public func viewDidAppear(_ animated: Bool) {
    speechRecognizer.delegate = self

    SFSpeechRecognizer.requestAuthorization { authStatus in
        /*
         The callback may not be called on the main thread. Add an
         operation to the main queue to update the record button's state.
         */
        OperationQueue.main.addOperation {
            switch authStatus {
            case .authorized:
                self.recordButton.isEnabled = true
                try! self.startRecording()
                self.recordButton.setTitle("Stop recording", for: [])


            case .denied:
                self.recordButton.isEnabled = false
                self.recordButton.setTitle(
                    "User denied access to speech recognition", 
                    for: .disabled
                )

            case .restricted:
                self.recordButton.isEnabled = false
                self.recordButton.setTitle(
                    "Speech recognition restricted on this device", 
                    for: .disabled
                )

            case .notDetermined:
                self.recordButton.isEnabled = false
                self.recordButton.setTitle(
                    "Speech recognition not yet authorized", 
                    for: .disabled
                )
            }
        }
    }
}

@IBAction func recordButtonTapped() {
    if audioEngine.isRunning {
        audioEngine.stop()
        recognitionRequest?.endAudio()
        recordButton.isEnabled = false
        recordButton.setTitle("Start Recording", for: [])
    } else {
        try! startRecording()
        recordButton.setTitle("Stop recording", for: [])
    }
}

private func startRecording() throws {

    // Cancel the previous task if it's running.
    if let recognitionTask = recognitionTask {
        recognitionTask.cancel()
        self.recognitionTask = nil
    }

    let audioSession = AVAudioSession.sharedInstance()
    try audioSession.setCategory(AVAudioSessionCategoryRecord)
    try audioSession.setMode(AVAudioSessionModeMeasurement)
    try audioSession.setActive(true, with: .notifyOthersOnDeactivation)

    recognitionRequest = SFSpeechAudioBufferRecognitionRequest()

    guard let inputNode = audioEngine.inputNode else { 
        fatalError("Audio engine has no input node") 
    }
    guard let recognitionRequest = recognitionRequest else { 
        fatalError("Unable to created a SFSpeechAudioBufferRecognitionRequest object") 
    }

    // Configure request so that results are returned before audio 
    // recording is finished
    recognitionRequest.shouldReportPartialResults = true

    // A recognition task represents a speech recognition session.
    // We keep a reference to the task so that it can be cancelled.
    recognitionTask = speechRecognizer.recognitionTask(
        with: recognitionRequest
    ) { result, error in
        var isFinal = false

        if let result = result {
            self.textView.text = result.bestTranscription.formattedString
            isFinal = result.isFinal
        }

        if error != nil || isFinal {
            self.audioEngine.stop()
            inputNode.removeTap(onBus: 0)

            self.recognitionRequest = nil
            self.recognitionTask = nil

            self.recordButton.isEnabled = true
        }
    }

    let recordingFormat = inputNode.outputFormat(forBus: 0)
    inputNode.installTap(
        onBus: 0, 
        bufferSize: 1024,
        format: recordingFormat
    ) { (buffer: AVAudioPCMBuffer, when: AVAudioTime) in
        self.recognitionRequest?.append(buffer)
    }

    audioEngine.prepare()

    try audioEngine.start()

    textView.text = "(Go ahead, I'm listening)"
}

// MARK: SFSpeechRecognizerDelegate

public func speechRecognizer(
    _ speechRecognizer: SFSpeechRecognizer, 
    availabilityDidChange available: Bool
) {
    if available {
        recordButton.isEnabled = true
        recordButton.setTitle("Start Recording", for: [])
    } else {
        recordButton.isEnabled = false
        recordButton.setTitle("Recognition not available", for: .disabled)
    }
}

// MARK: Interface Builder actions


}

该应用程序运行良好。但我想实现在 X 秒静音时停止音频引擎。

Answer 1

也许使用具有指定间隔的计时器，并在每次获得语音输入时失效。

您创建了一个始终失效的计时器，并在用户说话时在其上创建了一个新计时器。当用户停止说话时，时间结束并结束

示例:

class text {
var timer:Timer?
   func startRecording() { createTimer(4) }

   func whileRecording() { createTimer(1) }

   func createTimer(_ interval:Double) {
       timer?.invalidate()
       timer =   Timer.scheduledTimer(withTimeInterval: interval, repeats: false) { (_) in
           if self.audioEngine.isRunning {
               self.stopRecording()
           }
       }
   }

}