SpeechRecognizer.RecognizeOnceAsync Method

Definition

Namespace:

Microsoft.CognitiveServices.Speech

Assembly:

Microsoft.CognitiveServices.Speech.csharp.dll

Package:

Microsoft.CognitiveServices.Speech v1.42.0

Starts speech recognition as an asynchronous operation.

public System.Threading.Tasks.Task<Microsoft.CognitiveServices.Speech.SpeechRecognitionResult> RecognizeOnceAsync ();

member this.RecognizeOnceAsync : unit -> System.Threading.Tasks.Task<Microsoft.CognitiveServices.Speech.SpeechRecognitionResult>

Public Function RecognizeOnceAsync () As Task(Of SpeechRecognitionResult)

Returns

Task<SpeechRecognitionResult>

A task representing the recognition operation. The task returns a value of SpeechRecognitionResult

Examples

The following example creates a speech recognizer, and then gets and prints the recognition result.

public async Task SpeechSingleShotRecognitionAsync()
{
    // Creates an instance of a speech config with specified subscription key and region.
    // Replace with your own subscription key and service region (e.g., "westus").
    var config = SpeechConfig.FromSubscription("YourSubscriptionKey", "YourServiceRegion");

    // Creates a speech recognizer using microphone as audio input. Default language: en-us
    using (var recognizer = new SpeechRecognizer(config))
    {
        Console.WriteLine("Say something...");

        // Starts speech recognition, and returns after a single utterance is recognized. 
        // The end of a single utterance is determined by listening for silence at the end 
        // or until a timeout period has elapsed.  The task returns the
        // recognition text as result.
        //
        // Note: Since RecognizeOnceAsync() returns only a single utterance, 
        // it is suitable only for single shot recognition like command or query.
        // For long-running multi-utterance recognition, 
        // use StartContinuousRecognitionAsync() instead.

        var result = await recognizer.RecognizeOnceAsync();

        // Checks result.
        if (result.Reason == ResultReason.RecognizedSpeech)
        {
            Console.WriteLine($"RECOGNIZED: Text={result.Text}");
        }
        else if (result.Reason == ResultReason.NoMatch)
        {
            Console.WriteLine($"NOMATCH: Speech could not be recognized.");
        }
        else if (result.Reason == ResultReason.Canceled)
        {
            var cancellation = CancellationDetails.FromResult(result);
            Console.WriteLine($"CANCELED: Reason={cancellation.Reason}");

            if (cancellation.Reason == CancellationReason.Error)
            {
                Console.WriteLine($"CANCELED: ErrorCode={cancellation.ErrorCode}");
                Console.WriteLine($"CANCELED: ErrorDetails={cancellation.ErrorDetails}");
                Console.WriteLine($"CANCELED: Did you update the subscription info?");
            }
        }
    }
}

Remarks

The end of a single utterance is determined by listening for silence at the end, or until a timeout period has elapsed. The task returns the recognized speech in **SpeechRecognitionResult.Text**.

You can call **StopContinuousRecognitionAsync** to stop recognition before a phrase has been recognized.

Since this method returns only a single utterance, it is suitable only for single shot recognition like command or query. For long-running multi-utterance recognition, use **StartContinuousRecognitionAsync** instead.

See also: Get started with speech-to-text