.NET Capture Webcam into memory using avicap32.dll

Code
Public Class Webcam

    Inherits NativeWindow



#Region " P/Invokes "



    <DllImport("User32.dll")> _

    Private Shared Function SendMessage(hWnd As IntPtr, wMsg As UInteger, wParam As IntPtr, lParam As IntPtr) As IntPtr

    End Function



    <DllImport("avicap32.dll", EntryPoint:="capGetDriverDescription", CharSet:=CharSet.Auto)> _

    Private Shared Function GetDriverDescription(wDriver As Short, lpszName As String, cbName As Integer, lpszVer As String, cbVer As Integer) As Boolean

    End Function



    <DllImport("avicap32.dll", CharSet:=CharSet.Auto)> _

    Private Shared Function capCreateCaptureWindow(lpszWindowName As String, dwStyle As Integer, _

      x As Integer, y As Integer, nWidth As Integer, _

      nHeight As Integer, hWndParent As IntPtr, _

      nID As Integer) As IntPtr

    End Function



    <DllImport("user32.dll")> _

    Private Shared Function DestroyWindow(Handle As Integer) As Boolean

    End Function



#End Region



#Region " Constants "



    Private Const WM_CAP_START As Short = &H400

    Private Const WM_CAP_DRIVER_CONNECT As Integer = WM_CAP_START + 10

    Private Const WM_CAP_DRIVER_DISCONNECT As Integer = WM_CAP_START + 11

    Private Const WM_CAP_EDIT_COPY As Integer = WM_CAP_START + 30

    Private Const WM_CAP_GRAB_FRAME = WM_CAP_START + 60

    Private Const WM_CAP_SET_PREVIEW As Integer = WM_CAP_START + 50

    Private Const WM_CAP_SET_PREVIEWRATE As Integer = WM_CAP_START + 52

    Private Const WM_CAP_SET_SCALE As Integer = WM_CAP_START + 53

    Private Const WM_CAP_DLG_VIDEOSOURCE As Integer = WM_CAP_START + 42

    Private Const WM_CAP_STOP As Integer = WM_CAP_START + 68

    Private Const WS_CHILD As Integer = &H4000000

    Private Const WM_CAP_SET_CALLBACK_FRAME As Integer = WM_CAP_START + 5

    Private Const WM_CAP_SET_CALLBACK_VIDEO_STREAM As Integer = WM_CAP_START + 6

    Private Const WM_CAP_SEQUENCE_NOFILE As Integer = WM_CAP_START + 63

    Private Const WS_VISIBLE As Integer = &H1000000

    Private Const SWP_NOMOVE As Short = &H2S

    Private Const SWP_NOSIZE As Short = 1

    Private Const SWP_NOZORDER As Short = &H4S

    Private Const HWND_BOTTOM As Short = 1



#End Region



    Private iDevice As Integer = 0

    Private CamHandle As IntPtr

    Private FG As capVideoStreamCallback



    <StructLayout(LayoutKind.Sequential)> _

    Private Structure VIDEOHDR

      Public lpData As IntPtr

      Public dwBufferLength As UInteger

      Public dwBytesUsed As UInteger

      Public dwTimeCaptured As UInteger

      Public dwUser As UIntPtr

      Public dwFlags As UInteger

      <VBFixedArray(3)> Public dwReserved As UIntPtr()

    End Structure



    Private Sub Initialize()

      CreateHandle(New CreateParams)



      FG = New capVideoStreamCallback(AddressOf FrameGrabbedCallBack)



      EncoderParameters = New EncoderParameters(1)

      Encoder = Imaging.Encoder.Quality

      JPEGEncoder = GetEncoder(ImageFormat.Jpeg)



      CamHandle = capCreateCaptureWindow(iDevice.ToString, WS_VISIBLE Or WS_CHILD, 0, 0, 640, 480, Handle, 0)



      SendMessage(CamHandle, WM_CAP_DRIVER_CONNECT, iDevice, 0)



      Dim Ptr As IntPtr = Marshal.GetFunctionPointerForDelegate(FG)

      SendMessage(CamHandle, WM_CAP_SET_CALLBACK_VIDEO_STREAM, 0, Ptr)



      SendMessage(CamHandle, WM_CAP_SEQUENCE_NOFILE, 0, 0)



    End Sub



    Private Delegate Function capVideoStreamCallback(hWnd As IntPtr, lpVHdr As IntPtr) As IntPtr

    Private Function FrameGrabbedCallBack(hWnd As IntPtr, lpVHdr As IntPtr) As IntPtr

      'Convert lpVHdr to VIDEOHDR Structure using Marshal.PtrToStructure

      'Make bitmap from the lpdata pointer



      MsgBox("Callback!")

End Sub

End Class