Getting output from Process

Question

I load a film clip, use FFmpeg to convert it. That all works but I want to show the Process output within a RichTextBox on my Form. I can output the text to a msgBox but don't get any output to the RichTextBox.

I have attached the code used and would be grateful for any help.

Public MediaFolder As String = System.Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) & "\"

    Delegate Sub SetTextCallback(ByVal [text] As String)

    'openfiledialog to load film clip for conversion

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        If OpenFileDialog1.ShowDialog() = DialogResult.OK Then

            If OpenFileDialog1.FileName <> "" Then

                'takes the film, file, and concerts to avi and places in media tmp_videos folder

                Dim ffmpegProg As String = Application.StartupPath & "\ffmpeg.exe"

                Dim FilmSource As String

                Dim FilmDestination As String

                FilmSource = Replace(OpenFileDialog1.FileName, "\", "\\")

                FilmSource = Chr(34) & FilmSource & Chr(34)

                FilmDestination = Chr(34) & MediaFolder & "test.avi" & Chr(34)

                FilmDestination = Replace(FilmDestination, "\", "\\")

                Dim myProcess As System.Diagnostics.Process = New System.Diagnostics.Process()

                myProcess.StartInfo.UseShellExecute = False

                myProcess.StartInfo.CreateNoWindow = True

                myProcess.StartInfo.FileName = ffmpegProg

                myProcess.StartInfo.Arguments = " -i " & FilmSource & " -target pal-dvd -y " & FilmDestination

                myProcess.StartInfo.RedirectStandardOutput = True

                myProcess.StartInfo.RedirectStandardInput = True

                myProcess.StartInfo.RedirectStandardError = True

                myProcess.EnableRaisingEvents = True

                AddHandler myProcess.OutputDataReceived, AddressOf Me.HandleProcessOutput

                AddHandler myProcess.ErrorDataReceived, AddressOf Me.StandardErrorHandler

                ' myProcess.OutputDataReceived += New DataReceivedEvent.Handler(myProcess_OutputDataReceived)

                myProcess.Start()

                myProcess.BeginOutputReadLine()

                myProcess.BeginErrorReadLine()

                    myProcess.WaitForExit()

                    myProcess.Close()

                    RichTextBox1.Text = "finished"

            End If

        End If

    End Sub

    'Output sub

    Private Sub HandleProcessOutput(ByVal sender As Object, ByVal e As System.Diagnostics.DataReceivedEventArgs)

        SetText(e.Data)

    End Sub

    'Error handling

    Private Sub StandardErrorHandler(ByVal sender As Object, ByVal e As System.Diagnostics.DataReceivedEventArgs)

        SetText(e.Data)

    End Sub

    'check which threads 

    Private Sub SetText(ByVal [text] As String)

        If Me.RichTextBox1.InvokeRequired Then

            Dim d As New SetTextCallback(AddressOf SetText)

            Me.Invoke(d, New Object() {[text]})

        Else

            Me.RichTextBox1.Text = [text]

        End If

    End Sub