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RecognizedAudio.WriteToWaveStream(Stream) Method

  • Reference

Definition

Namespace:
System.Speech.Recognition
Assembly:
System.Speech.dll
Package:
System.Speech v9.0.0
Source:
RecognizedAudio.cs
Source:
RecognizedAudio.cs
Source:
RecognizedAudio.cs

Writes audio to a stream in Wave format.

public:
 void WriteToWaveStream(System::IO::Stream ^ outputStream);
public void WriteToWaveStream (System.IO.Stream outputStream);
member this.WriteToWaveStream : System.IO.Stream -> unit
Public Sub WriteToWaveStream (outputStream As Stream)

Parameters

outputStream
Stream

The stream that will receive the audio data.

Examples

The following example creates a speech recognition grammar for name input, adds a handler for the SpeechRecognized event, and loads the grammar into an in-process speech recognizer. Then it writes the audio information for the name portion of the input to an audio file. The audio file is used as input to a SpeechSynthesizer object, which speaks a phrase that includes the recorded audio.

private static void AddNameGrammar(SpeechRecognitionEngine recognizer)  
{  
  GrammarBuilder builder = new GrammarBuilder();  
  builder.Append("My name is");  
  builder.AppendWildcard();  

  Grammar nameGrammar = new Grammar(builder);  
  nameGrammar.Name = "Name Grammar";  
  nameGrammar.SpeechRecognized +=  
    new EventHandler<SpeechRecognizedEventArgs>(  
      NameSpeechRecognized);  

  recognizer.LoadGrammar(nameGrammar);  
}  

// Handle the SpeechRecognized event of the name grammar.  
private static void NameSpeechRecognized(  
  object sender, SpeechRecognizedEventArgs e)  
{  
  Console.WriteLine("Grammar ({0}) recognized speech: {1}",  
    e.Result.Grammar.Name, e.Result.Text);  

  try  
  {  
    // The name phrase starts after the first three words.  
    if (e.Result.Words.Count < 4)  
    {  

      // Add code to check for an alternate that contains the   
wildcard.  
      return;  
    }  

    RecognizedAudio audio = e.Result.Audio;  
    TimeSpan start = e.Result.Words[3].AudioPosition;  
    TimeSpan duration = audio.Duration - start;  

    // Add code to verify and persist the audio.  
    string path = @"C:\temp\nameAudio.wav";  
    using (Stream outputStream = new FileStream(path, FileMode.Create))  
    {  
      RecognizedAudio nameAudio = audio.GetRange(start, duration);  
      nameAudio.WriteToWaveStream(outputStream);  
      outputStream.Close();  
    }  

    Thread testThread =  
      new Thread(new ParameterizedThreadStart(TestAudio));  
    testThread.Start(path);  
  }  
  catch (Exception ex)  
  {  
    Console.WriteLine("Exception thrown while processing audio:");  
    Console.WriteLine(ex.ToString());  
  }  
}  

// Use the speech synthesizer to play back the .wav file  
// that was created in the SpeechRecognized event handler.  

private static void TestAudio(object item)  
{  
  string path = item as string;  
  if (path != null && File.Exists(path))  
  {  
    SpeechSynthesizer synthesizer = new SpeechSynthesizer();  
    PromptBuilder builder = new PromptBuilder();  
    builder.AppendText("Hello");  
    builder.AppendAudio(path);  
    synthesizer.Speak(builder);  
  }  
}

Remarks

Audio data is written to outputStream in Wave format, which includes a resource interchange file format (RIFF) header.

The WriteToAudioStream method uses the same binary format, but does not include the Wave header.

Applies to

See also