ISpeechPhraseAlternate Code Example (SAPI 5.3)

Microsoft Speech API 5.3

Interface: ISpeechPhraseAlternate

ISpeechPhraseAlternate Code Example

The following Visual Basic form code displays use of the ISpeechPhraseAlternate object. It demonstrates recognition and the EmulateRecognition method.

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

• A text box called Text1
• Two list boxes, called List1 and List2
• Two command buttons, called Command1 and Command2

Paste this code into the Declarations section of the form and add a reference to Microsoft Speech Object Library in Visual Basic's References dialog box.

The solitaire grammar file sol.xml is located in the default directory for a standard SAPI SDK installation. If the file is not there, use the path to an existing version. If no file is available, use the example code from VB Application Sample: Command and Control Recognition if needed.

The Form_Load procedure creates a recognizer, a recognition context, and a grammar object. It loads the grammar object with sol.xml, the Solitaire grammar from the SAPI sample code, then activates the command and control (C and C) and dictation components of the grammar, and places a Solitaire command in the text box. Text matching the rules of the Solitaire grammar will produce better recognition results, but in order to demonstrate recognition alternates, it is necessary to enter phrases that do not satisfy grammar rules.

The command button, captioned Recognition, speaks text from the text box into an audio .wav file and then performs speech recognition of that file. The command button captioned EmulateRecognition simply calls the EmulateRecognition method.

When alternates are available, the code displays three alternates in the top list box, and shows the phrase elements of one alternate in the lower list box. Click any alternate to display its phrase elements in the lower list box. Double click any alternate to perform the Commit method on that alternate. In the illustration below, the first alternate is incorrect; the second alternate is highlighted, and its phrase elements are displayed in the lower list box.

The data displayed in the lower list box is the same data displayed in the ISpeechPhraseElement code example. Please see that page for full details.

  
Option Explicit

Const WAVEFILENAME = "C:\ISpeechPhraseAlternate.wav"

Private blnAlternatesExist As Boolean

Private MyRecognizer As SpeechLib.SpInprocRecognizer
Private MyGrammar As SpeechLib.ISpeechRecoGrammar
Private MyFileStream As SpeechLib.SpFileStream
Private MyVoice As SpeechLib.SpVoice

Private PhraseInfo As SpeechLib.ISpeechPhraseInfo
Private PhraseAlts1 As SpeechLib.ISpeechPhraseAlternate
Private PhraseAlts2 As SpeechLib.ISpeechPhraseAlternates
Private PhraseElem As SpeechLib.ISpeechPhraseElement
Private PhraseElems As SpeechLib.ISpeechPhraseElements

Private WithEvents MyRecoContext As SpeechLib.SpInProcRecoContext

Private Sub Command1_Click()
    On Error GoTo EH

    List1.Clear
    List2.Clear
    Screen.MousePointer = vbHourglass

    ' Create ISpeechPhraseAlternate.wav file from text in text box.
    Set MyFileStream = MakeWAVFileFromText(Text1.Text, WAVEFILENAME)

    'Set the file as recognizer's input stream
    MyFileStream.Open WAVEFILENAME
    Set MyRecognizer.AudioInputStream = MyFileStream

EH:
    If Err.Number Then ShowErrMsg
End Sub

Private Sub Command2_Click()
    On Error GoTo EH

    List1.Clear
    List2.Clear
    Screen.MousePointer = vbHourglass
    MyRecoContext.Recognizer.EmulateRecognition Text1.Text

EH:
    If Err.Number Then ShowErrMsg
End Sub

Private Sub Form_Load()
    On Error GoTo EH

    ' Create Recognizer, RecoContext, Grammar, and Voice
    Set MyRecognizer = New SpInprocRecognizer
    Set MyRecoContext = MyRecognizer.CreateRecoContext
    Set MyGrammar = MyRecoContext.CreateGrammar(16)
    Set MyVoice = New SpVoice

    ' Load Grammar with solitaire XML, set active
    MyGrammar.CmdLoadFromFile "C:\sol.xml", SLOStatic
    MyGrammar.CmdSetRuleIdState 0, SGDSActive           'Set MyRecoContext & MyRecoContext active
    MyGrammar.DictationSetState SGDSActive              'Set Dictation active

    Text1.Text = "let's go over minor details"
    Command1.Caption = "&Recognition;"
    Command2.Caption = "&EmulateRecognition;"

EH:
    If Err.Number Then ShowErrMsg
End Sub

Private Function MakeWAVFileFromText _
   (ByVal strText As String, _
    ByVal strFName As String) _
    As SpFileStream

    On Error GoTo EH

    ' Declare identifiers:
    Dim FileStream As SpFileStream
    Dim Voice As SpVoice

    ' Instantiate Voice and FileStream objects:
    Set Voice = New SpVoice
    Set FileStream = New SpFileStream

    ' Open specified .wav file, set voice output
    ' to file, and speak synchronously:
    FileStream.Open strFName, SSFMCreateForWrite, True
    Set Voice.AudioOutputStream = FileStream
    Voice.Speak strText, SVSFIsXML

    ' Close file and return reference to FileStream object:
    FileStream.Close
    Set MakeWAVFileFromText = FileStream

EH:
    If Err.Number Then ShowErrMsg
End Function

Private Function PhonesToString(ByVal arrV As Variant) As String
    Dim ii As Integer, S As String

    On Error GoTo EH

    If IsEmpty(arrV) Then
        PhonesToString = ""
    Else
        For ii = 0 To UBound(arrV)
            If Len(S) Then
                S = S & "," & arrV(ii)
            Else
                S = arrV(ii)
            End If
        Next ii
        PhonesToString = S
    End If

EH:
    If Err.Number Then ShowErrMsg
End Function

Private Sub MyRecoContext_Recognition _
   (ByVal StreamNumber As Long, _
    ByVal StreamPosition As Variant, _
    ByVal RecognitionType As SpeechLib.SpeechRecognitionType, _
    ByVal Result As SpeechLib.ISpeechRecoResult)
    Dim nn As Integer

    On Error GoTo EH

    Set PhraseAlts2 = Result.Alternates(3)       'May or may not be available
    If PhraseAlts2 Is Nothing Then

        'No alternates when speech matches PhraseAlts1 grammar rule
        'No alternates when using EmulateRecognition
        blnAlternatesExist = False
        List1.AddItem Result.PhraseInfo.GetText
        If Len(Result.PhraseInfo.Rule.Name) Then
            List1.AddItem "   matches rule """ & Result.PhraseInfo.Rule.Name & """"
        End If
        Set PhraseInfo = Result.PhraseInfo
    Else

        blnAlternatesExist = True
        nn = 0
        For Each PhraseAlts1 In PhraseAlts2
            List1.AddItem "alt" & Format(nn) & ": " & PhraseAlts1.PhraseInfo.GetText
            nn = nn + 1
        Next
        Set PhraseInfo = PhraseAlts2.Item(0).PhraseInfo
    End If

    List1.ListIndex = 0     'Highlight the selected alternate
    Call DisplayPhraseElements(0)
    Screen.MousePointer = vbDefault

EH:
    If Err.Number Then ShowErrMsg
End Sub

Private Sub MyRecoContext_EndStream _
   (ByVal StreamNumber As Long, _
    ByVal StreamPosition As Variant, _
    ByVal StreamReleased As Boolean)

    On Error GoTo EH

    'Recognition uses the Filestream, EmulateReco does not
    If ActiveControl.Caption = "&Recognition;" Then
        MyFileStream.Close
        DoEvents
        MyFileStream.Open WAVEFILENAME
        MyVoice.SpeakStream MyFileStream
        MyFileStream.Close
    End If
    Screen.MousePointer = vbDefault

EH:
    If Err.Number Then ShowErrMsg
End Sub

Private Sub DisplayPhraseElements(Index As Integer)
    Dim X As String
    Dim T As String
    Dim A1 As Long, A2 As Long
    Dim T1 As Long, T2 As Long
    Dim C1 As Single, C2 As Integer, C3 As Integer

    On Error GoTo EH

    List2.Clear

    'If no alternates, then there is only one PhraseInfo
    If blnAlternatesExist = True Then
        Set PhraseInfo = PhraseAlts2.Item(Index).PhraseInfo
    End If

    For Each PhraseElem In PhraseInfo.Elements

        'Audio data
        A1 = PhraseElem.AudioStreamOffset
        A2 = PhraseElem.AudioSizeBytes
        X = Format(A1, "000000") & " " & Format(A2, "000000") & "  "

        'Time data
        T1 = PhraseElem.AudioTimeOffset
        T2 = PhraseElem.AudioSizeTime
        X = X & Format(T1, "000000000") & " " & Format(T2, "000000000") & "  "

        'Display attributes
        X = X & Format(PhraseElem.DisplayAttributes) & " "

        'Confidences
        C1 = PhraseElem.EngineConfidence
        C2 = PhraseElem.ActualConfidence
        C3 = PhraseElem.RequiredConfidence
        T = "(" & Format(C1) & " " & Format(C2) & " " & Format(C3) & ")"
        X = X & Left(T & "         ", 14)

        'Text and pronunciation
        X = X & Left(PhraseElem.DisplayText & "              ", 14)
        X = X & PhonesToString(PhraseElem.Pronunciation)

        List2.AddItem X
    Next

EH:
    If Err.Number Then ShowErrMsg
End Sub

Private Sub List1_Click()
    Call DisplayPhraseElements(List1.ListIndex)
End Sub

Private Sub List1_DblClick()
    PhraseAlts2.Item(List1.ListIndex).Commit
End Sub

Private Sub ShowErrMsg()

    ' Declare identifiers:
    Const NL = vbNewLine
    Dim T As String

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

End Sub