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ISpeechRecoResult RecoContext Property (SAPI 5.3)

Speech API 5.3
Microsoft Speech API 5.3

Interface: ISpeechRecoResult

RecoContext Property

The RecoContext property retrieves the current ISpeechRecoContext for the recognizer.

Applications may have multiple recognition contexts open at the same time. RecoContext provides a means to determine which context owns the recognition. For example, in situations with more than recognition context, a recognition result may call RecoContext to get the context associated with it. The returned context may be changed afterward and will not affect other contexts.


Set: (This property is read-only)
Get: ISpeechRecoContext = ISpeechRecoResult.RecoContext


The owning object.
Set: (This property is read-only)
Get: An SpSharedRecoContext variable that gets the property.


The following Visual Basic form code reads the RecoContext property of a RecoResult. If more than one recognition context exists, the one owning RecoResult is retrieved. When the event interest is changed, no other recognition contexts are affected.

To run this code, paste it into the Declarations section of a form that contains no controls. In addition to the usual reference to the Microsoft Speech Object Library, this code also needs a reference to the simpleaudio 1.0 Type Library.

Option Explicit


' Text-to-Speech variables:
Dim WithEvents Voice As SpVoice
Dim EndofStream As Boolean
Dim AudioPlugOut As SpAudioPlug

' Speech Recognition variables:
Dim WithEvents RecoContext As SpInProcRecoContext
Dim Grammar As ISpeechRecoGrammar
Dim Recognizer As SpInprocRecognizer
Dim AudioPlugIn As SpAudioPlug

Private Sub Form_Load()

    Const Text = "One of the world's seven wonders"
    Dim Output As Variant

    On Error GoTo EH

    Set Voice = New SpVoice

    ' Set up output audio:
    Set AudioPlugOut = New SpAudioPlug
    AudioPlugOut.Init True, AUDIOFORMAT
    Set Voice.AudioOutputStream = AudioPlugOut

    ' Set up input audio:
    Set AudioPlugIn = New SpAudioPlug
    AudioPlugIn.Init False, AUDIOFORMAT
    Set Recognizer = New SpInprocRecognizer
    Set Recognizer.AudioInputStream = AudioPlugIn

    ' Set up speech recognition and explicitly set
    ' flag to retain audio portion of recognition
    ' (default behavior is not to retain):
    Set RecoContext = Recognizer.CreateRecoContext
    RecoContext.RetainedAudio = SRAORetainAudio
    Set Grammar = RecoContext.CreateGrammar(1)
    Grammar.DictationSetState SGDSActive

    ' Speak some text to be recognized.
    Voice.Speak Text, SVSFlagsAsync

    Do While EndofStream = False

        ' Get audio data from audio object.
        Output = AudioPlugOut.GetData

        ' Output audio data to input audio object--
        If (Len(Output) * 2 <> 0) Then
            AudioPlugIn.SetData (Output)
        End If


    Grammar.DictationSetState SGDSInactive

    If Err.Number Then ShowErrMsg
End Sub

Private Sub RecoContext_Recognition _
   (ByVal StreamNumber As Long, _
    ByVal StreamPosition As Variant, _
    ByVal RecognitionType As SpeechLib.SpeechRecognitionType, _
    ByVal Result As SpeechLib.ISpeechRecoResult)

    Dim myContext As ISpeechRecoContext

    On Error GoTo EH
    ' Change event interest of recognition context:
    Set myContext = Result.RecoContext()
    myContext.EventInterests = SREFalseRecognition

    If Err.Number Then ShowErrMsg
End Sub

Private Sub Voice_EndStream _
   (ByVal StreamNumber As Long, _
    ByVal StreamPosition As Variant)

    EndofStream = True

End Sub

Private Sub ShowErrMsg()

    ' Declare identifiers:
    Dim T As String

    T = "Desc: " & Err.Description & vbNewLine
    T = T & "Err #: " & Err.Number
    MsgBox T, vbExclamation, "Run-Time Error"

End Sub
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