SetFormatData Method

'Declaration
 
Public Sub SetFormatData( _
   ByVal DataSize As Integer, _
   ByVal Data As Object _
) 

Public _result As Boolean = False
      Public _form As ConvertCtrlForm = New ConvertCtrlForm()
      Public Sub GetFormatDataExample()
         ' reference the convert control
         Dim convertctrl As ConvertCtrl = _form.ConvertCtrl

         ' input file and output files
         Dim inFile As String = Path.Combine(LEAD_VARS.MediaDir, "MediaType_ShortSource.avi")
         Dim outFilePfx As String = Path.Combine(LEAD_VARS.MediaDir, "MediaType_GetFormatDataExample")
         Dim sampleFileName As String

         ' This example demonstrates how to use SampleTarget and MediaSample
         ' objects to directly access sample frames from a conversion graph.

         Try
            ' set the source and target files
            convertctrl.SourceFile = inFile

            ' set the preview
            convertctrl.Preview = True

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

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

            ' set the sample target's accepted media type
            st.SetAcceptedMediaType(mtTarget)

            ' assign the sample target to the capture control
            convertctrl.TargetObject = st
            convertctrl.TargetFormat = TargetFormatType.StillImage

            ' run the convert
            convertctrl.StartConvert()

            Dim msFrame As MediaSample = st.GetSample(1000)
            Dim sampleStart, sampleStop As Long

            Do While Not msFrame Is Nothing
               ' get the sample target's connected media type
               Dim mtSample As MediaType = st.GetConnectedMediaType()

               ' demonstrate media type properties copy
               Dim mtCopy As MediaType = New MediaType()
               CopyMediaTypeAttributes(mtSample, mtCopy)

               ' get the sample times
               msFrame.GetTime(sampleStart, sampleStop)

               ' create the file name for this frame bitmap
               sampleFileName = String.Format("{0}_{1}-{2}.bmp", outFilePfx, sampleStart, sampleStop)

               ' create the bitmap for this frame
               WriteSampleBitmap(sampleFileName, msFrame, mtSample) ' mtCopy);

               Try
                  ' create a media sample using the captured sample from above 
                  msFrame = st.GetSample(1000)
               Catch cex As COMException
                  ' if we have reached the end of stream we are finished
                         If cex.ErrorCode = CInt(ErrorCode.VFW_E_SAMPLE_REJECTED_EOS) _
                            OrElse cex.ErrorCode = CInt(ErrorCode.VFW_E_WRONG_STATE) Then
                             Exit Do
                         ElseIf cex.ErrorCode = CInt(ErrorCode.VFW_E_TIMEOUT) Then
                             Continue Do
                         Else
                             Throw cex
                         End If
               End Try

               ' set the result
               _result = True

               ' 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.
               If convertctrl.State = ConvertState.Running Then
                  Application.DoEvents()
               End If
            Loop
         Catch e1 As Exception
            _result = False
         End Try
      End Sub

      Private Function CopyMediaTypeAttributes(ByVal pSource As MediaType, ByVal pDest As MediaType) As Boolean
         Dim fmtDataSize As Integer

         ' return error if either source or dest is null
         If pSource Is Nothing OrElse pDest Is Nothing Then
            Return False
         End If

         ' get the format data size
         fmtDataSize = pSource.FormatSize

         ' any format data
         If fmtDataSize > 0 Then
            pDest.SetFormatData(fmtDataSize, pSource.GetFormatData(fmtDataSize)) ' yes, then copy it
         Else
            pDest.FormatSize = 0 ' no, just set the dest size to zero
         End If

         ' copy type, subtype, formattype
         pDest.Type = pSource.Type
         pDest.SubType = pSource.SubType
         pDest.FormatType = pSource.FormatType

         ' set dest fixed size samples and temporal compression
         pDest.FixedSizeSamples = pSource.FixedSizeSamples
         pDest.TemporalCompression = pSource.TemporalCompression

         ' copy samplesize
         pDest.SampleSize = pSource.SampleSize

         Return True
      End Function

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