Convert Audio File to text using System.Speech

I am looking to convert a .wav file recorded through an android phone at 16000 to text using C#; namely the System.Speech开发者_JAVA技巧 namespace. My code is mentioned below;

recognizer.SetInputToWaveFile(Server.MapPath("~/spoken.wav"));
recognizer.LoadGrammar(new DictationGrammar());
RecognitionResult result = recognizer.Recognize();
label1.Text = result.Text;

The is working perfectly with sample .wav "Hello world" file. However when i record something on teh phone and try to convert to on the pc, the converted text is no where close to what i had recoreded. Is there some way to make sure the audio file is transcribed accurately?

What format is the phone's audio file recorded in? Is the file encoded? Microsoft recognizer supports PCM, ALaw, and ULaw. Make sure you are recording in a supported format. You can look at the RecognizerInfo.SupportedAudioFormats Property - http://msdn.microsoft.com/en-us/library/system.speech.recognition.recognizerinfo.supportedaudioformats(v=VS.90).aspx and check the formats your recognizer version supports.

Did you listen to the file you recorded on your phone? Is it noisy? Does it sound clear? Make sure you are feeding the recognizer the best sounding audio you can.

Since you are using a Dictation grammar, I'm assuming you're using Windows 7. Have you tried training the recognizer? My understanding is that the dictation grammar performance can be improved by training and that the standard Windows 7 speech recognition training will help its performance - http://windows.microsoft.com/en-US/windows7/Set-up-Speech-Recognition

Some other questions on StackOverflow may also give you some insights. See good Speech recognition API to start.

Full implementation details for exactly what you want can be found here:

Converting WAV audio to text using System.Speech

Imports System
Imports System.Speech.Recognition

Public Class Form1

    Dim WithEvents sre As SpeechRecognitionEngine

    Private Sub btnLiterate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLiterate.Click
        If TextBox1.Text.Trim.Length = 0 Then Exit Sub
        sre.SetInputToWaveFile(TextBox1.Text)
        Dim r As RecognitionResult
        r = sre.Recognize()
        If r Is Nothing Then
            TextBox2.Text = "Could not fetch result"
            Return
        End If
        TextBox2.Text = r.Text
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TextBox1.Text = String.Empty
        Dim dr As DialogResult
        dr = OpenFileDialog1.ShowDialog()
        If dr = Windows.Forms.DialogResult.OK Then
            If Not OpenFileDialog1.FileName.Contains("wav") Then
                MessageBox.Show("Incorrect file")
            Else
                TextBox1.Text = OpenFileDialog1.FileName
            End If
        End If
    End Sub

    Public Sub New()

        ' This call is required by the Windows Form Designer.
        InitializeComponent()

        sre = New SpeechRecognitionEngine()

    End Sub

    Private Sub sre_LoadGrammarCompleted(ByVal sender As Object, ByVal e As System.Speech.Recognition.LoadGrammarCompletedEventArgs) Handles sre.LoadGrammarCompleted

    End Sub

    Private Sub sre_SpeechHypothesized(ByVal sender As Object, ByVal e As System.Speech.Recognition.SpeechHypothesizedEventArgs) Handles sre.SpeechHypothesized
        System.Diagnostics.Debug.Print(e.Result.Text)
    End Sub

    Private Sub sre_SpeechRecognitionRejected(ByVal sender As Object, ByVal e As System.Speech.Recognition.SpeechRecognitionRejectedEventArgs) Handles sre.SpeechRecognitionRejected
        System.Diagnostics.Debug.Print("Rejected: " & e.Result.Text)
    End Sub

    Private Sub sre_SpeechRecognized(ByVal sender As Object, ByVal e As System.Speech.Recognition.SpeechRecognizedEventArgs) Handles sre.SpeechRecognized
        System.Diagnostics.Debug.Print(e.Result.Text)
    End Sub

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim words As String() = New String() {"triskaidekaphobia"}
        Dim c As New Choices(words)
        Dim grmb As New GrammarBuilder(c)
        Dim grm As Grammar = New Grammar(grmb)
        sre.LoadGrammar(grm)
    End Sub

End Class 

or try this link Audio to text software free