text to speech


This article shows to you , how to creating a Text-to-Speech application using VB.Net with Visual Studio 2008.

 Download source code for How to create a Text-to-Speech application using VB.NET with Visual studio 2008?

Introduction


.Net Framwork 3.5 provides set of speech libraries for developing a Text-to-Speech. The System.Speech.Synthesis namespace provides lot of classes for Text-to-Speech. Mainly InstalledVoice, VoiceInfo and SpeechSynthesizer etc.. 



Step by Step Procedures


Create a new project in Visual Studio 2008 

Select the New Project from File Menu

  • -> New Project window appears 
  • -> browse to other languagues 
  • -> select visual basic and windows application enter Name as TextToSpeechVB.

when the project is created you have to add a reference to the System.Speech.dll under .NET Tab.

 

Now design the windows form with the following controls

  1. ComboBox  control(cmbInstalled)  – to list all available installed voices
  2. Button Control(btnStart) – To starting the Text-to-Speech
  3. Button Control(btnEnd)   – To stop the Text-to-Speech
  4. Track Bar control(btnRate) – to control the Text-to-Speech speed rate.
  5. Trach Bar Control( btnVolume)- to control the Text-to-Speech control volume.

The Speed rate should be a number between -10 and 10 values. A normal rate is -1 and the volum between 0 and 100.

So Assign the btnVolumn Trackbar control Minimum and Maximum properties to 0 and 100 and the btnRate trackbar control minimum and maximum properties to -10 and 10.
Default set to btnVolumn Value properties to 50 and btnRate value properties to -1.
Create a new instance of a SpeechSynthesizer under namespace System.Speech.Synthesis. This class have the  properties and methods that can start, stop and control audio activites specified text. Need to add the Imports statements are

Imports System.Speech.Synthesis
Imports System.Collections.ObjectModel

and declare the below line as private or public

Private p_objSynth As New SpeechSynthesizer

Next write a method which retrieves a list of installed voices are in local system. By default, Windows Xp available voices are (LH Michael(Gents voice),LH Michelle(Women voice),Microsoft sam(Gents voice)). This voice recognizes English words, punctuation and grammar rules. If you want to more voices , installed valid voices.

p_objSynth.GetInstalledVoices() method retrieving a list of all installed voices and returns a ReadOnlyCollection of InstalledVoice objects

Dim objvoices As ReadOnlyCollection(Of InstalledVoice) = p_objSynth.GetInstalledVoices(Globalization.CultureInfo.CurrentCulture)

Now On_PageLoad event loads cmbInstalled combobox with installed voices

Dim objvoices As ReadOnlyCollection(Of InstalledVoice) = p_objSynth.GetInstalledVoices(Globalization.CultureInfo.CurrentCulture)
Dim objvoiceInformation As VoiceInfo = objvoices(0).VoiceInfo
For Each tmpvoice As InstalledVoice In objvoices
   objvoiceInformation = tmpvoice.VoiceInfo
   cmbInstalled.Items.Add(objvoiceInformation.Name.ToString)
Next

Handle Volume and Speed Rate for SpeechSynthesizer

Volume

Write code for handle volume and speed rate changes,earlier mentioned above volume must be a number between 0 and 100. Mention number becomes the value for the Volume property of the active SpeechSynthesizer class instance.The user changes the position of the slider in the volumeTrackBar control to raised the valueChanged event

Private Sub btnVolume_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnVolume.ValueChanged
        p_objSynth.Volume = btnVolume.Value
End Sub
Speed Rate

To set the speed rate by assigning the rate property of the SpeechSynthesizer in ValueChanged event.

Private Sub btnRate_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRate.ValueChanged
        p_objSynth.Rate = btnRate.Value
End Sub
Stop Speech

For stop speech write code in btnEnd button Event

mySynth.SpeakAsyncCancelAll() method to stop the Text-to-Speech.
Start Speech

Now Start the Text-to-Speech write code in btnStart button event

p_objSynth.SelectVoice(cmbInstalled.Text)
p_objSynth.SpeakAsync(txtVoiceText.Text)

Complete Code Listing

Imports System.Speech.Synthesis

Imports System.Collections.ObjectModel



Public Class Form1
    Private p_objSynth As New SpeechSynthesizer
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Dim objvoices As ReadOnlyCollection(Of InstalledVoice) = p_objSynth.GetInstalledVoices(Globalization.CultureInfo.CurrentCulture)
        Dim objvoiceInformation As VoiceInfo = objvoices(0).VoiceInfo
        For Each tmpvoice As InstalledVoice In objvoices
            objvoiceInformation = tmpvoice.VoiceInfo
            cmbInstalled.Items.Add(objvoiceInformation.Name.ToString)
        Next

    End Sub

    Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click

        p_objSynth.SelectVoice(cmbInstalled.Text)
        p_objSynth.SpeakAsync(txtVoiceText.Text)


    End Sub

   
    Private Sub btnVolume_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnVolume.ValueChanged
        p_objSynth.Volume = btnVolume.Value

    End Sub





    Private Sub btnRate_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRate.ValueChanged
        p_objSynth.Rate = btnRate.Value
    End Sub

    Private Sub btnEnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEnd.Click
        p_objSynth.SpeakAsyncCancelAll()
    End Sub
End Class

Conclusion

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