SpeechRecognitionEngine BackgroundWorker

Question

我想寫一個C＃應用程序使用Windows窗體和System.Speech將WAV文件轉換爲文本。我在網上看到很多關於如何做到這一點的示例，但沒有一個是非常強大的。我希望編寫一個應用程序，它可以使用BackgroundWorker線程解析較小的大型WAV文件，但在我的線程的DoWork函數中，當它調用engine.Recognize（）時會收到以下異常：

「No audio輸入被提供給該識別器。使用方法SetInputToDefaultAudioDevice如果將麥克風連接到系統，否則使用SetInputToWaveFile，SetInputToWaveStream或SetInputToAudioStream從執行語音識別預錄音頻」

這裏是在我的DoWork（）的代碼功能：

SpeechRecognitionEngine engine = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("en-US")); 
engine.SetInputToWaveFile(fname); 
engine.LoadGrammar(new DictationGrammar()); 
engine.BabbleTimeout = TimeSpan.FromSeconds(10.0); 
engine.EndSilenceTimeout = TimeSpan.FromSeconds(10.0); 
engine.EndSilenceTimeoutAmbiguous = TimeSpan.FromSeconds(10.0); 
engine.InitialSilenceTimeout = TimeSpan.FromSeconds(10.0); 

BackgroundWorker w = (BackgroundWorker)sender; 
while (true) 
{  
RecognitionResult data = engine.Recognize(); 
if (data == null) 
    break; 
if (w == null) //our thread died from beneath us 
    break; 
if (!w.IsBusy) //our thread died from beneath us 
    break; 
if (w.CancellationPending) //notice to cancel 
    break; 
w.ReportProgress(0, data.Text); 
} 

我是l運行多個運行此代碼的BackgroundWorker線程。如果我使用單個線程，我不會看到這個問題。

Answer 1

您可以嘗試這種方法。我測試了它的控制檯和Windows窗體應用程序類型。

class Program { 
    public static void Main() { 
     var r1 = new Recognizer(@"c:\proj\test.wav"); 
     r1.Completed += (sender, e) => Console.WriteLine(r1.Result.Text); 

     var r2 = new Recognizer(@"c:\proj\test.wav"); 
     r2.Completed += (sender, e) => Console.WriteLine(r2.Result.Text); 

     Console.ReadLine(); 
    } 
} 

class Recognizer { 
    private readonly string _fileName; 
    private readonly AsyncOperation _operation; 
    private volatile RecognitionResult _result; 

    public Recognizer(string fileName) { 
     _fileName = fileName; 
     _operation = AsyncOperationManager.CreateOperation(null);    
     _result = null; 

     var worker = new Action(Run); 
     worker.BeginInvoke(delegate(IAsyncResult result) { 
      worker.EndInvoke(result); 
     }, null);    
    } 

    private void Run() { 
     try { 
      SpeechRecognitionEngine engine = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("en-US")); 
      engine.SetInputToWaveFile(_fileName); 
      engine.LoadGrammar(new DictationGrammar()); 
      engine.BabbleTimeout = TimeSpan.FromSeconds(10.0); 
      engine.EndSilenceTimeout = TimeSpan.FromSeconds(10.0); 
      engine.EndSilenceTimeoutAmbiguous = TimeSpan.FromSeconds(10.0); 
      engine.InitialSilenceTimeout = TimeSpan.FromSeconds(10.0); 
      _result = engine.Recognize(); 
     } 
     finally { 
      _operation.PostOperationCompleted(delegate { 
       RaiseCompleted(); 
      }, null); 
     } 
    } 

    public RecognitionResult Result { 
     get { return _result; } 
    } 

    public event EventHandler Completed; 

    protected virtual void OnCompleted(EventArgs e) { 
     if (Completed != null) 
      Completed(this, e); 
    } 

    private void RaiseCompleted() { 
     OnCompleted(EventArgs.Empty); 
    } 
}