更改视图会导致音频引擎出现故障

如何解决更改视图会导致音频引擎出现故障

我正在制作一个应用，它使用音频引擎和听写来解释用户所说的内容。我有两个视图可以在使用类 UINavigationController 下的 pushViewController 方法之间进行更改：主视图控制器（称为“ViewController”）和图形视图控制器（称为“GraphViewController”）。当我更改视图并从 GraphViewController 返回到 ViewController 时，音频引擎开始以不合理的速度（约 10 毫秒）完成缓冲区并拒绝录制任何声音。

注意：音频引擎设置在我的 ViewController 类中，我的应用程序的主视图。

这里有一些错误片段可以更好地解释我的问题：

authorized
2021-03-28 01:14:29.631330-0400 DictoCounter[24060:4935105] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x6000032fb1e0> F8BB1C28-BAE8-11D6-9C31-00039315CD46
2021-03-28 01:14:29.797620-0400 DictoCounter[24060:4935239] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2
Text: Hello
Text: Hello hello
Text: Hello hello hello
Text: Hello hello hello
Text: Hello hello hello
Text: Hello hello hello this
Text: Hello hello hello this is
Text: Hello hello hello this is working
Text: Hello hello hello this is working normally
Text: Hello hello hello this is working normally

当应用启动时，主视图控制器 (ViewController) 加载并且音频引擎开始录制。一切正常，缓冲区每 30 秒填充一次。

当我导航到 GraphViewController（通过使用 ViewController 上的按钮）时，音频引擎继续正常缓冲。但是，当我使用视图左上角的“

2021-03-28 01:15:10.643091-0400 DictoCounter[24060:4935105] Words successfully saved.
2021-03-28 01:15:10.644663-0400 DictoCounter[24060:4936029] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2
2021-03-28 01:15:10.654050-0400 DictoCounter[24060:4935938] [Utility] +[AFAggregator logDictationFailedWithError:] Error Domain=kAFAssistantErrorDomain Code=209 "(null)"
completed buffer
2021-03-28 01:15:10.674991-0400 DictoCounter[24060:4935105] Words successfully saved.
2021-03-28 01:15:10.676519-0400 DictoCounter[24060:4936031] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2
2021-03-28 01:15:10.683803-0400 DictoCounter[24060:4935215] [Utility] +[AFAggregator logDictationFailedWithError:] Error Domain=kAFAssistantErrorDomain Code=209 "(null)"
completed buffer
2021-03-28 01:15:10.706812-0400 DictoCounter[24060:4935105] Words successfully saved.
2021-03-28 01:15:10.708591-0400 DictoCounter[24060:4936032] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2
2021-03-28 01:15:10.718311-0400 DictoCounter[24060:4935936] [Utility] +[AFAggregator logDictationFailedWithError:] Error Domain=kAFAssistantErrorDomain Code=209 "(null)"
completed buffer
2021-03-28 01:15:10.741680-0400 DictoCounter[24060:4935105] Words successfully saved.
2021-03-28 01:15:10.743231-0400 DictoCounter[24060:4936033] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2
2021-03-28 01:15:10.754336-0400 DictoCounter[24060:4935939] [Utility] +[AFAggregator logDictationFailedWithError:] Error Domain=kAFAssistantErrorDomain Code=209 "(null)"
completed buffer
2021-03-28 01:15:10.774254-0400 DictoCounter[24060:4935105] Words successfully saved.
2021-03-28 01:15:10.775783-0400 DictoCounter[24060:4936034] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2
2021-03-28 01:15:10.787332-0400 DictoCounter[24060:4935938] [Utility] +[AFAggregator logDictationFailedWithError:] Error Domain=kAFAssistantErrorDomain Code=209 "(null)"
completed buffer
2021-03-28 01:15:10.814357-0400 DictoCounter[24060:4935105] Words successfully saved.
2021-03-28 01:15:10.815785-0400 DictoCounter[24060:4936035] [aurioc] 323: Unable to join I/O thread to workgroup ((null)): 2

这显然是一个问题，因为如果音频引擎仅记录短时间突发，则缓冲区无法接收任何音频输入。我在其他堆栈溢出帖子以及 iOS 论坛中搜索过此错误，但似乎没有人遇到与我相同的更改视图问题。我将在下面粘贴相关代码：

//AUdio ENGINE- inside ViewController
    func recognizeAudioStream() {
        let speechRecognizer = SFSpeechRecognizer()
        
        //performs speech recognition on live audio; as audio is captured,call append
        //to request object,call endAudio() to end speech recognition
        var recognitionRequest: SFSpeechAudioBufferRecognitionRequest?
        
        //determines & edits state of speech recognition task (end,start,cancel,etc)
        var recognitionTask: SFSpeechRecognitionTask?
        
        let audioEngine = AVAudioEngine()
        
        
        func startRecording() throws{
            
            //cancel prevIoUs audio task
            recognitionTask?.cancel()
            recognitionTask = nil
            
            //get info from microphone
            let audioSession = AVAudioSession.sharedInstance()
            try audioSession.setCategory(.record,mode: .measurement,options: .duckOthers)
            try audioSession.setActive(true,options: .notifyOthersOnDeactivation)
            
            let inputNode = audioEngine.inputNode
            
            //audio buffer; takes a continuous input of audio and recognizes speech
            recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
            //allows device to print results of your speech before you're done talking
            recognitionRequest?.shouldReportPartialResults = true
            
            
            recognitionTask = speechRecognizer!.recognitionTask(with: recognitionRequest!) {result,error in
                
                var isFinal = false
                
                if let result = result{ //if we can let result be the nonoptional version of result,then
                    isFinal = result.isFinal
                    print("Text: \(result.bestTranscription.formattedString)")
                    
                }
                
                if error != nil || result!.isFinal{ //if an error occurs or we're done speaking
                    
                    audioEngine.stop()
                    inputNode.removeTap(onBus: 0)
                    
                    recognitionTask = nil
                    recognitionRequest = nil

                    let bufferText = result?.bestTranscription.formattedString.components(separatedBy: (" "))
                    print("completed buffer")
                    
                    self.addToDictionary(wordNames: bufferText)
                    
                    sortedWordsDict = wordsDict.sorted {
                        return $0.value > $1.value
                    }
                    
                    allWords = [] //reset the array to reload words
                    
                    for (wordKey,countValue) in sortedWordsDict{
                        allWords.append(Word(word: wordKey,count: countValue))
                    }
                    
                    self.saveWords() //saves allWords list to file
                    
                    tempWords = Array(allWords.prefix(numWords)) //only show first 50 words
                    
                    wordsColl.reloadData()
//
                    do{
                        try startRecording()
                    }
                    catch{
                        print(error)
                    }
                    
                }
            
            }
            
            //configure microphone; let the recording format match with that of the bus we are using
            let recordingFormat = inputNode.outputFormat(forBus: 0)
            
            //contents of buffer will be dumped into recognitionRequest and into result,where
            //it will then be transcribed and printed out
            //1024 bytes = dumping "limit": once buffer fills to 1024 bytes,it is appended to recognitionRequest
            inputNode.installTap(onBus: 0,bufferSize: 1024,format: recordingFormat) { (buffer: AVAudioPCMBuffer,when: AVAudioTime) in
                recognitionRequest?.append(buffer)
            }
            
            audioEngine.prepare()
            try audioEngine.start()
        }
        
        do{
            try startRecording()
        }
        catch{
            print(error)
        }
        
        
    }

底部的 do-catch 语句确保麦克风不断记录用户的声音。这对我有用（在这种情况下，更改视图似乎会使音频引擎出现故障）。我还没有找到任何更好的方法来实现这个继续录制功能，所以如果有更有效的方法，请告诉我！继续，

//INSIDE ViewController
 @objc func goToHome(){
        let homeView = ViewController()
        navigationController?.pushViewController(homeView,animated: true)
    }
    
    @objc func goToGraph(){
        print("pressed")
        let graphView = GraphViewController()
        navigationController?.pushViewController(graphView,animated: true)
    }

这些函数控制视图的推送。最后，这是我的 SceneDelegate.swift 相关代码：

//INSIDE SceneDelegate.swift
func scene(_ scene: UIScene,willConnectTo session: UIScenesession,options connectionoptions: UIScene.Connectionoptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard,the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingScenesession` instead).
        if let windowScene = scene as? UIWindowScene{
            let window = UIWindow(windowScene: windowScene)
            
            let viewController = ViewController()
            window.rootViewController = UINavigationController(rootViewController: viewController)
            self.window = window
            window.makeKeyAndVisible()
        }
    }

主类ViewController中的这段代码调用了recognizeAudioStream()：

    override func viewDidAppear(_ animated: Bool) {
        wordsColl.reloadData()
        let speechRecognizer = SFSpeechRecognizer()
        requestDictAccess();
        
        if speechRecognizer!.isAvailable { //if the user has granted permission
            speechRecognizer?.supportsOnDeviceRecognition = true //for offline data
            
            recognizeAudioStream()
        }
        
    }

感谢您阅读这篇文章！如果您需要更多信息，请告诉我。