AudioPosition Property

SpeechRecognitionEngine.AudioPosition Property


Gets the current location in the audio stream being generated by the device that is providing input to the SpeechRecognitionEngine.

Namespace:   System.Speech.Recognition
Assembly:  System.Speech (in System.Speech.dll)

public TimeSpan AudioPosition { get; }

Property Value

Type: System.TimeSpan

The current location in the audio stream being generated by the input device.

The AudioPosition property references the input device's position in its generated audio stream. By contrast, the RecognizerAudioPosition property references the recognizer's position within its audio input. These positions can be different. For example, if the recognizer has received input for which it has not yet generated a recognition result then the value of the RecognizerAudioPosition property is less than the value of the AudioPosition property.

In the following example, the in-process speech recognizer uses a dictation grammar to match speech input. A handler for the SpeechDetected event writes to the console the AudioPosition, RecognizerAudioPosition, and AudioLevel when the speech recognizer detects speech at its input.

using System;
using System.Speech.Recognition;

namespace SampleRecognition
  class Program
    private static SpeechRecognitionEngine recognizer;
    public static void Main(string[] args)

      // Initialize an in-process speech recognition engine for US English.
      using (recognizer = new SpeechRecognitionEngine(
        new System.Globalization.CultureInfo("en-US")))

        // Create a grammar for finding services in different cities.
        Choices services = new Choices(new string[] { "restaurants", "hotels", "gas stations" });
        Choices cities = new Choices(new string[] { "Seattle", "Boston", "Dallas" });

        GrammarBuilder findServices = new GrammarBuilder("Find");

        // Create a Grammar object from the GrammarBuilder and load it to the recognizer.
        Grammar servicesGrammar = new Grammar(findServices);

        // Add handlers for events.
        recognizer.SpeechRecognized +=
          new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRecognized);
        recognizer.SpeechDetected +=
          new EventHandler<SpeechDetectedEventArgs>(recognizer_SpeechDetected);

        // Start asynchronous recognition.
        Console.WriteLine("Starting asynchronous recognition...");

        // Keep the console window open.

    // Gather information about detected speech and write it to the console.
    static void recognizer_SpeechDetected(object sender, SpeechDetectedEventArgs e)
      Console.WriteLine("Speech detected:");
      Console.WriteLine("  Audio level: " + recognizer.AudioLevel);
      Console.WriteLine("  Audio position at the event: " + e.AudioPosition);
      Console.WriteLine("  Current audio position: " + recognizer.AudioPosition);
      Console.WriteLine("  Current recognizer audio position: " + 

    // Write the text of the recognition result to the console.
    static void recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
      Console.WriteLine("\nSpeech recognized: " + e.Result.Text);

      // Add event handler code here.

.NET Framework
Available since 3.0
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