CaptureFrame Method

'Declaration
 
Public Overridable Sub CaptureFrame() 

Public _result As Boolean = False
      Public _form As CaptureCtrlForm = New CaptureCtrlForm()
      Public Sub CaptureFrameExample()
         ' reference the capture control
         Dim capturectrl As CaptureCtrl = _form.CaptureCtrl

         ' output file
         Dim outFile As String = Path.Combine(LEAD_VARS.MediaDir, "CaptureCtrl_CaptureFrameExample.bmp")

         Try
            ' set the video capture device, use your capture device name here
            If capturectrl.VideoDevices("Logitech") Is Nothing Then
               Throw New Exception("No Logitech video device available")
            End If

            capturectrl.VideoDevices("Logitech").Selected = True

            ' create a new sample target
            Dim st As SampleTarget = New SampleTarget()

            ' set the target media type for the video stream
            Dim amt As MediaType = New MediaType()
            amt.Type = Leadtools.Multimedia.Constants.MEDIATYPE_Video
            amt.SubType = Leadtools.Multimedia.Constants.MEDIASUBTYPE_RGB24
            st.SetAcceptedMediaType(amt)

            ' assign the sample target to the capture control
            capturectrl.TargetObject = st
            capturectrl.TargetFormat = TargetFormatType.AVI

            ' prepare the manual frames capture
            capturectrl.ReadyCapture(CaptureMode.ManualFrames)

            ' do something before the capture starts
            If capturectrl.IsModeAvailable(CaptureMode.ManualFrames) Then
            End If

            ' set the capture mode to manual frames
            capturectrl.StartCapture(CaptureMode.ManualFrames)

            ' capture a frame
            capturectrl.CaptureFrame()

            ' create a media sample using the captured sample from above 
            Dim ms As MediaSample = st.GetSample(-1)

            ' get the sample target's connected media type
            Dim mt As MediaType = st.GetConnectedMediaType()

            Dim bmp As Bitmap = WriteSampleBitmap(outFile, ms, mt)

            ' stop the capture
            capturectrl.StopCapture()

            ' check for the capture file and set the result
            If File.Exists(outFile) Then
               Dim test As Image = Bitmap.FromFile(outFile)
               _result = (test.Width = bmp.Width AndAlso test.Height = bmp.Height AndAlso test.PixelFormat = bmp.PixelFormat)
            End If
         Catch e1 As COMException
            _result = False
         Catch e2 As Exception
            _result = False
         End Try

         ' we'll loop on the state and pump messages for this example.
         ' but you should not need to if running from a Windows Forms application.
         Do While capturectrl.State = CaptureState.Running
            Application.DoEvents()
         Loop
      End Sub

      Private Function WriteSampleBitmap(ByVal outFile As String, ByVal ms As MediaSample, ByVal mt As MediaType) As Bitmap
         ' get the video information 
         Dim vih As VideoInfoHeader = mt.GetVideoFormatData()

         ' create a bitmap to hold the sample and copy it
         Dim bmp As Bitmap = New Bitmap(vih.bmiHeader.biWidth, vih.bmiHeader.biHeight, FormatFromBitCount(vih.bmiHeader.biBitCount))
         Dim bmpData As BitmapData = bmp.LockBits(New Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, bmp.PixelFormat)
         Marshal.Copy(ms.Buffer, 0, bmpData.Scan0, GetBitmapSize(bmp, vih.bmiHeader.biBitCount))
         bmp.UnlockBits(bmpData)

         ' flip the upside down buffer
         bmp.RotateFlip(RotateFlipType.Rotate180FlipX)

         ' save the image
         bmp.Save(outFile, ImageFormat.Bmp)
         Return bmp
      End Function

      Private Function FormatFromBitCount(ByVal bitCount As Integer) As PixelFormat
         Select Case bitCount
            Case 8
               Return PixelFormat.Format8bppIndexed
            Case 16
               Return PixelFormat.Format16bppRgb555
            Case 32
               Return PixelFormat.Format32bppRgb
            Case 48
               Return PixelFormat.Format48bppRgb
            Case 24
               Return PixelFormat.Format24bppRgb
         End Select
         Throw New Exception("Unrecognized bit count")
      End Function

      Private Function GetBitmapSize(ByVal bmp As Bitmap, ByVal bitCount As Integer) As Integer
         Dim pixelSize As Integer = CInt(Math.Log(CDbl(bitCount)))
         Return (bmp.Width * pixelSize + pixelSize And (Not 3)) * bmp.Height
      End Function

      Private Function GetBitmapScanRowSize(ByVal bmpSize As Integer, ByVal stride As Integer, ByVal width As Integer) As Integer
         Return CInt(bmpSize / (stride / width))
      End Function

      Public Sub CaptureFrame_Helper(ByVal sender As Object, ByVal e As EventArgs)
         ' set result
         _result = True
      End Sub

Public NotInheritable Class LEAD_VARS
   Public Const MediaDir As String = "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 175\Media";
End Class