ByteScout Screen Capturing SDK – VB.NET – Capture From Separate Thread

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ByteScout Screen Capturing SDK – VB.NET – Capture From Separate Thread

CapturingThread.vb

Imports System.Drawing
Imports System.IO
Imports System.Runtime.InteropServices
Imports System.Threading
Imports BytescoutScreenCapturingLib

' NOTE: if you are getting error like "invalid image" related to loading the SDK's dll then 
' try to do the following:
' 1) remove the reference to the SDK by View - Solution Explorer
' then click on References, select Bytescout... reference name and right-click it and select Remove
' 2) To re-add click on the menu: Project - Add Reference
' 3) In "Add Reference" dialog switch to "COM" tab and find Bytescout...
' 4) Select it and click "Add" 
' 5) Recompile the application 
' Note: if you need to run on both x64 and x86 then please make sure you have set "Embed Interop Types" to True for this reference

Public Class CapturingThread

    Public Shared Sub ThreadProc(ByVal obj As Object)

        Dim data As CapturingThreadData = DirectCast(obj, CapturingThreadData)
        data.Success = True

        ' Prepare Capturer:

        Dim capturer As New Capturer()
        capturer.RegistrationName = "demo"
        capturer.RegistrationKey = "demo"

        capturer.CaptureRectLeft = data.CaptureRectangle.Left
        capturer.CaptureRectTop = data.CaptureRectangle.Top
        capturer.CaptureRectWidth = data.CaptureRectangle.Width
        capturer.CaptureRectHeight = data.CaptureRectangle.Height

        capturer.OutputWidth = 640
        capturer.OutputHeight = 480

        ' // WMV and WEBM output use WMVVideoBitrate property to control output video bitrate
        ' // so try to increase it by x2 or x3 times if you think the output video are you are getting is laggy
        ' capturer.WMVVideoBitrate = capturer.WMVVideoBitrate * 2
        
        data.TempFile = Path.GetTempFileName()
        data.TempFile = Path.ChangeExtension(data.TempFile, ".wmv")

        capturer.OutputFileName = data.TempFile
        capturer.CapturingType = data.CaptureType

        ' set border around captured area if we are not capturing entire screen
        If capturer.CapturingType <> CaptureAreaType.catScreen And capturer.CapturingType <> CaptureAreaType.catWebcamFullScreen Then

            capturer.CaptureAreaBorderType = CaptureAreaBorderType.cabtDashed
            capturer.CaptureAreaBorderColor = CType(ColorTranslator.ToOle(Color.Red), UInteger)

        End If


        ' Wait for events:

        Dim events As WaitHandle() = New WaitHandle() {data.StartOrResumeEvent, data.PauseEvent, data.StopEvent}

        Try

            While (True)

                Dim i As Integer = WaitHandle.WaitAny(events)

                If events(i) Is data.StartOrResumeEvent Then

                    If Not capturer.IsRunning Then
                        capturer.Run()
                    End If

                ElseIf events(i) Is data.PauseEvent Then

                    If capturer.IsRunning Then
                        capturer.Pause()
                    End If

                ElseIf events(i) Is data.StopEvent Then

                    capturer.Stop()
                    Exit While

                End If
                
            End While

        Catch ex As Exception

            data.ErrorText = ex.Message
            data.Success = False

        Finally

            ' Release resources
            Marshal.ReleaseComObject(capturer)

        End Try

    End Sub

End Class

CapturingThreadData.vb

Imports System.Drawing
Imports System.Threading
Imports BytescoutScreenCapturingLib

Public Class CapturingThreadData

    Public CaptureType As CaptureAreaType
    Public TempFile As String
    Public CaptureRectangle As Rectangle = New Rectangle(0, 0, 320, 240)

    Public Success As Boolean
    Public ErrorText As String

    Public StartOrResumeEvent As AutoResetEvent = New AutoResetEvent(False) ' event signalling to start or resume the recodring
    Public PauseEvent As AutoResetEvent = New AutoResetEvent(False) ' event signalling to pause the recodring
    Public StopEvent As AutoResetEvent = New AutoResetEvent(False) ' event signalling to stop the recording 

End Class



Form1.vb

Imports System.Diagnostics
Imports System.IO
Imports System.Threading
Imports System.Windows.Forms
Imports BytescoutScreenCapturingLib

' NOTE: if you are getting error like "invalid image" related to loading the SDK's dll then 
' try to do the following:
' 1) remove the reference to the SDK by View - Solution Explorer
' then click on References, select Bytescout... reference name and right-click it and select Remove
' 2) To re-add click on the menu: Project - Add Reference
' 3) In "Add Reference" dialog switch to "COM" tab and find Bytescout...
' 4) Select it and click "Add" 
' 5) Recompile the application 
' Note: if you need to run on both x64 and x86 then please make sure you have set "Embed Interop Types" to True for this reference

Public Partial Class Form1
	Inherits Form

    Private _capturingThread As Thread
    Private _capturingThreadData As CapturingThreadData  ' data to exchange between form and capturing thread

    Public Sub New()

        InitializeComponent()

        _capturingThreadData = New CapturingThreadData()

        cmbCapturingType.SelectedIndex = 0

    End Sub

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

        Dim captureType As CaptureAreaType = CaptureAreaType.catMouse

        If cmbCapturingType.SelectedIndex = 1 Then
            captureType = CaptureAreaType.catScreen
        End If

        StartRecording(captureType)

    End Sub

    Private Sub btnPauseResume_Click(sender As System.Object, e As System.EventArgs) Handles btnPauseResume.Click

        PauseOrResumeRecording()

    End Sub

    Private Sub btnStop_Click(sender As Object, e As EventArgs) Handles btnStop.Click

        StopRecording()

    End Sub

    Private Sub StartRecording(ByVal captureType As CaptureAreaType)

        btnStart.Enabled = False
        btnPauseResume.Enabled = True
        btnStop.Enabled = True

        _capturingThreadData.CaptureType = captureType

        ' Start thread
        _capturingThread = New Thread(AddressOf CapturingThread.ThreadProc)
        _capturingThread.Start(_capturingThreadData)

        ' Signal to start the recording
        _capturingThreadData.StartOrResumeEvent.Set()
        
    End Sub

    Private Sub PauseOrResumeRecording()

        btnStart.Enabled = False
        btnPauseResume.Enabled = True
        btnStop.Enabled = True

        If btnPauseResume.Text = "Pause" Then
            ' Signal to pause
            _capturingThreadData.PauseEvent.Set()
            btnPauseResume.Text = "Resume"

        Else
            ' Signal to resume
            _capturingThreadData.StartOrResumeEvent.Set()
            btnPauseResume.Text = "Pause"
        End If

    End Sub

    Private Sub StopRecording()

        Cursor = Cursors.WaitCursor

        ' Signal to stop
        _capturingThreadData.StopEvent.Set()

        Try
            _capturingThread.Join()
        Finally
            Cursor = Cursors.Default
        End Try

        If Not _capturingThreadData.Success Then
            MessageBox.Show("Capturing failed. Error: " & _capturingThreadData.ErrorText)
        Else
            Dim dlg As New SaveFileDialog()
            dlg.DefaultExt = "*.wmv"
            dlg.Filter = "WMV files (*.wmv)|*.wmv|All files (*.*)|*.*"

            dlg.FileName = "Screencast"
            dlg.Title = "Save captured video as"

            If dlg.ShowDialog() = DialogResult.OK Then
                File.Copy(_capturingThreadData.TempFile, dlg.FileName, True)
                ' start the video in default associated application
                Process.Start(dlg.FileName)
            End If

            File.Delete(_capturingThreadData.TempFile)
        End If

        btnStart.Enabled = True
        btnPauseResume.Enabled = False
        btnStop.Enabled = False
        btnPauseResume.Text = "Pause"

    End Sub

    Private Sub Form1_FormClosing(sender As System.Object, e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing

        _capturingThreadData.StopEvent.Set()

    End Sub
End Class

Program.vb

Imports System.Collections.Generic
Imports System.Windows.Forms

NotInheritable Class Program
	Private Sub New()
	End Sub
	''' <summary>
	''' The main entry point for the application.
	''' </summary>
	<STAThread> _
	Friend Shared Sub Main()
		Application.EnableVisualStyles()
		Application.SetCompatibleTextRenderingDefault(False)
		Application.Run(New Form1())
	End Sub
End Class

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