Help !! bin2hex avec multi-threading !! Urgent !!

Bonjour,
Je cherche quelqu'un qui serait capable de me faire fonctionner cela correctement (problème décrit à la fin) :
Public Class bin2hex
    Dim processes As Process
    Dim Thread1 As System.Threading.Thread
    Dim Thread2 As System.Threading.Thread

    Private Sub Open_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Open.Click
        OFD.InitialDirectory = My.Application.Info.DirectoryPath
        OFD.ShowDialog()
        txtIN.Text = OFD.FileName
    End Sub

    Private Sub Save_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Save.Click
        SFD.FileName = txtIN.Text & ".hex"
        SFD.ShowDialog()
        txtOUT.Text = SFD.FileName
    End Sub

    Private Sub Process_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Process.Click
        Dim input() As Byte = IO.File.ReadAllBytes(txtIN.Text)
        Dim output As String = ""
        PB.Visible = True
        PB.Maximum = input.Length + 2
        processes = New Process(input)
        CheckForIllegalCrossThreadCalls = False
        AddHandler processes.Progress, AddressOf progress
        Thread1 = New System.Threading.Thread(AddressOf processes.thread1)
        Thread1.Start()
        Thread2 = New System.Threading.Thread(AddressOf processes.thread2)
        Thread2.Start()
    End Sub

    Sub progress(ByVal pos As Long)
        Try
            PB.Value = pos
            Speed1.Text = "Thread1 : " & Int(processes.totalcalc1 / processes.totaltime1) & "calc/ms"
            Speed2.Text = "Thread2 : " & Int(processes.totalcalc2 / processes.totaltime2) & "calc/ms"
        Catch
        End Try
        Application.DoEvents()
        If pos >= processes.input.Length - 1 Then
            IO.File.WriteAllText(txtOUT.Text, processes.output)
            Try
                If My.Application.CommandLineArgs(0) <> ""And My.Application.CommandLineArgs(1) <> ""Then End
            Catch
            End Try
            MsgBox("Finished !", MsgBoxStyle.Information)
            PB.Visible = False
            Thread1.Abort()
            Thread2.Abort()
        End If
    End Sub

    Private Sub bin2hex_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try
            If My.Application.CommandLineArgs(0) <> ""And My.Application.CommandLineArgs(1) <> ""Then
                txtIN.Text = My.Application.CommandLineArgs(0)
                txtOUT.Text = My.Application.CommandLineArgs(1)
                My.Application.DoEvents()
                Process_Click(sender, e)
            End If
        Catch
        End Try
    End Sub
End Class

Public Class process
    Public input() AsByte
    Public output() AsChar
    Public working1 AsBoolean
    Public working2 AsBoolean
    Dim watch1 As New Diagnostics.Stopwatch
    Dim watch2 As New Diagnostics.Stopwatch
    Public totaltime1 As Long
    Public totaltime2 As Long
    Public totalcalc1 As Long
    Public totalcalc2 As Long
    Dim pos As Long = -1

    Sub New(ByVal _input() As Byte)
        input = _input
        ReDim output(((input.Length - 1) * 2) + 1)
    End Sub

    Sub thread1()
        While pos < input.Length - 1
            working1 = True
            pos += 1
            watch1.Reset()
            watch1.Start()
            Dim MyPos As Long = pos
            Dim hexa As String = Hex(input(MyPos))
            If hexa.Length < 2 Then
                output(MyPos * 2) = "0"
                output((MyPos * 2) + 1) = hexa
            Else
                output(MyPos * 2) = Mid(hexa, 1, 1)
                output((MyPos * 2) + 1) = Mid(hexa, 2, 1)
            End If
            watch1.Stop()
            totaltime1 += watch1.ElapsedMilliseconds
            totalcalc1 += 1
            RaiseEvent Progress(pos)
            working1 = False
        End While
     End Sub
    Sub thread2()
        While pos < input.Length - 1
            working2 = True
            pos += 1
            watch2.Reset()
            watch2.Start()
            Dim MyPos As Long = pos
            Dim hexa As String = Hex(input(MyPos))
            If hexa.Length < 2 Then
                output(MyPos * 2) = "0"
                output((MyPos * 2) + 1) = hexa
            Else
                output(MyPos * 2) = Mid(hexa, 1, 1)
                output((MyPos * 2) + 1) = Mid(hexa, 2, 1)
            End If
            watch2.Stop()
            totaltime2 += watch2.ElapsedMilliseconds
            totalcalc2 += 1
            RaiseEvent Progress(pos)
            working2 = False
        End While
    End Sub
    Public Event Progress(ByVal pos As Long)
End Class

J'explique mon problème, en fait mon fichier de sortie semble être bon mais contient des vides
Si quelqu'un saurait aussi me l'optimiser car j'ai des fichiers de plus en plus conséquents à traiter ...

Merci à tous