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SpeechRecoContext SoundEnd Event (SAPI 5.3)

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Microsoft Speech API 5.3

Interface: ISpeechRecoContext Events

SoundEnd Event

The SoundEnd event occurs when the speech recognition (SR) engine encounters an end of sound in the audio input stream.

SoundStart indicates a sound level significant enough to be a voice. When that sound stops, a SoundEnd event is generated. A recognition attempt occurs only after a SoundEnd event; hence, long continuous speaking periods may take an equally long time to process.

Light background noise will not register as an input sound. Likewise a loud noise will be considered the start of an input sound. If the sound is constant, a time-out occurs sending a SoundEnd event.

  
    SpeechRecoContext.SoundEnd(
     StreamNumber As Long,
     StreamPosition As Variant
)

Parameters

  • StreamNumber
    Specifies the StreamNumber.
  • StreamPosition
    Specifies the StreamPosition.

Example

The following Visual Basic form code demonstrates the use of the SoundStart and SoundEnd events. The application displays a stream number and notifications that a sound has begun or ended. It also displays a successful recognition result.

To run this code, create a form with the following controls:

  • Two labels called Label1 and Label2

Paste this code into the Declarations section of the form.

The Form_Load procedure creates and activates a dictation grammar.

  Public WithEvents RC As SpSharedRecoContext
Public myGrammar As ISpeechRecoGrammar

Private Sub Form_Load()
    Set RC = New SpSharedRecoContext
	
    Set myGrammar = RC.CreateGrammar
    myGrammar.DictationSetState SGDSActive
End Sub

Private Sub RC_Recognition(ByVal StreamNumber As Long, ByVal StreamPosition As Variant, ByVal RecognitionType As SpeechLib.SpeechRecognitionType, ByVal Result As SpeechLib.ISpeechRecoResult)
    Label1.Caption = Result.PhraseInfo.GetText
End Sub

Private Sub RC_SoundEnd(ByVal StreamNumber As Long, ByVal StreamPosition As Variant)
    Label2.Caption = "Sound end at position: " & StreamPosition
End Sub

Private Sub RC_SoundStart(ByVal StreamNumber As Long, ByVal StreamPosition As Variant)
    Label2.Caption = "Sound start"
End Sub