Perform the following steps to create and run a multimedia convert application to extract video frames using SampleTargets with the LEADTOOLS Multimedia ConvertCtrl control.
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Start Visual Studio .NET.
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Choose File->New->Project... from the menu.
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In the New Project dialog box, choose either "Visual C# Projects" or "VB Projects" in the Projects Type List, and choose "Windows Application " in the Templates List.
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Type the project name as "Multimedia Frame Extractor" in the Project Name field, and then click OK. If desired, type a new location for your project or select a directory using the Browse button, and then click OK.
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In the "Solution Explorer" window, right-click the "References" folder, and select "Add Reference..." from the context menu. In the "Add Reference" dialog box, select the ".NET" tab and select Leadtools.Multimedia and click OK. If this DLL does not appear under the .NET tab, you will need select the Browse tab and add it from the "<LEADTOOLS_INSTALLDIR>\Bin\Dotnet\Win32 " folder, by selecting the following DLL:
After browsing, click the Select button and then press the OK button to add the above DLL to the application.
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Next, we need to add the using/import directive for this DLL to our Form's source file. Switch Form1 to code view (right-click Form1 in the Solution Explorer then choose View Code) and add the following lines to the beginning of the file:
Imports Leadtools.Multimedia
using Leadtools.Multimedia;
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While still in code view, declare the following private variables for use later:
Private _sourceFile As String
Private _targetPath As String
private string _sourceFile;
private string _targetPath;
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Next, we need to add an instance of the ConvertCtrl to the form. Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and drag a ConvertCtrl control on the form. NOTE: If you do not have ConvertCtrl in your toolbox, select Tools->Choose Toolbox Items from the menu. Click Browse and then select Leadtools.Multimedia.dll from "<LEADTOOLS_INSTALLDIR>\Bin\Dotnet\Win32" and then click Open and then click OK. After adding it to the form, set the following properties on the convert control:
| Property |
Value |
| Name |
_convertctrl |
| Anchor |
Top, Bottom, Left, Right |
| BackColor |
Black |
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Go to the toolbox (View->Toolbox) and drag a ProgressBar control on the form (below the convert control) and set the following properties:
| Property |
Value |
| Name |
_progress |
| Anchor |
Bottom, Left, Right |
| Step |
1 |
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Next, we will add a text control and browse button for the source video file selection. Go to the toolbox (View->Toolbox) and drag a Text control and a Button control to the form (below the progress bar) and set the following properties:
| Property |
Value |
| Name |
_textSrcFile |
| Anchor |
Bottom, Left, Right |
| ReadOnly |
True |
| BackColor |
ControlLightLight |
| Name |
_buttonBrowseSrc |
| Text |
Source... |
| Anchor |
Bottom, Right |
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Next, we will add another text control and browse button to select the output folder for extracted frames. Go to the toolbox (View->Toolbox) and drag a Text control and a Button control to the bottom of the form and set the following properties:
| Property |
Value |
| Name |
_textTargetPath |
| Anchor |
Bottom, Left, Right |
| ReadOnly |
True |
| BackColor |
ControlLightLight |
| Name |
_buttonBrowseTarget |
| Text |
... |
| Anchor |
Bottom, Right |
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Now, we need one final button to start the conversion/frames extraction work. Go to the toolbox (View->Toolbox) and drag a Button control to the bottom of the form and set the following properties:
| Property |
Value |
| Name |
_buttonConvert |
| Text |
Extract |
| Anchor |
Bottom, Right |
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While still in design view, select the properties for the form and add an event handler to the Form1 Load event. Code this event handler as follows:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
_sourceFile = "<LEADTOOLS_INSTALLDIR>\Media\DaDa_DVD_MPEG2.mpg"
_targetPath = Path.Combine(Directory.GetCurrentDirectory(), "Frames")
If (Not Directory.Exists(_targetPath)) Then
Directory.CreateDirectory(_targetPath)
End If
_textSrcFile.Text = _sourceFile
_textTargetPath.Text = _targetPath
End Sub
private void Form1_Load(object sender, System.EventArgs e)
{
_sourceFile = @"<LEADTOOLS_INSTALLDIR>\Media\DaDa_DVD_MPEG2.mpg";
_targetPath = Path.Combine(Directory.GetCurrentDirectory(), "Frames");
if (!Directory.Exists(_targetPath))
Directory.CreateDirectory(_targetPath);
_textSrcFile.Text = _sourceFile;
_textTargetPath.Text = _targetPath;
}
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Also, add an event handler to the _convertctrl Progress event and code it as follows:
Private Sub _convertctrl_Progress(ByVal sender As System.Object, ByVal e As ProgressEventArgs) Handles _convertctrl.Progress
_progress.Value = CInt((_progress.Maximum * e.percent / 100))
End Sub
private void _convertctrl_Progress(object sender, ProgressEventArgs e)
{
_progress.Value = (int)(_progress.Maximum * e.percent / 100);
}
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Now, add an event handler to the _convertctrl Complete event to let us know when the conversion/extraction process is completed. Code this event handler as follows:
Private Sub _convertctrl_Complete(ByVal sender As System.Object, ByVal e As EventArgs) Handles _convertctrl.Complete
MessageBox.Show("Frame Extraction Complete")
_buttonBrowseSrc.Enabled = True
_buttonBrowseTarget.Enabled = True
_buttonConvert.Enabled = True
End Sub
private void _convertctrl_Complete(object sender, EventArgs e)
{
MessageBox.Show("Frame Extraction Complete");
_buttonBrowseSrc.Enabled = true;
_buttonBrowseTarget.Enabled = true;
_buttonConvert.Enabled = true;
}
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Add an event handler to the _buttonBrowseSrc Click event to select the source video file for processing. Code this event handler as follows:
Private Sub _buttonBrowseSrc_Click(ByVal sender As Object, ByVal e As EventArgs) Handles _buttonBrowseSrc.Click
Dim ofn As OpenFileDialog = New OpenFileDialog()
ofn.FileName = _sourceFile
ofn.FilterIndex = 0
If _textSrcFile.Text <> String.Empty Then
ofn.InitialDirectory = Path.GetDirectoryName(_textSrcFile.Text)
Else
ofn.InitialDirectory = Directory.GetCurrentDirectory()
End If
ofn.Multiselect = False
ofn.Title = "Select Source Video"
ofn.CheckFileExists = True
ofn.Filter = "MPEG2 Video Files (*.mpg)|*.mpg | All files (*.*)|*.*"
If ofn.ShowDialog() = DialogResult.OK Then
_textSrcFile.Text = ofn.FileName
_sourceFile = _textSrcFile.Text
End If
End Sub
private void _buttonBrowseSrc_Click(object sender, EventArgs e)
{
OpenFileDialog ofn = new OpenFileDialog();
ofn.FileName = _sourceFile;
ofn.FilterIndex = 0;
if (_textSrcFile.Text != string.Empty)
ofn.InitialDirectory = Path.GetDirectoryName(_textSrcFile.Text);
else
ofn.InitialDirectory = Directory.GetCurrentDirectory();
ofn.Multiselect = false;
ofn.Title = "Select Source Video";
ofn.CheckFileExists = true;
ofn.Filter = "MPEG2 Video Files (*.mpg)|*.mpg | All files (*.*)|*.*";
if (ofn.ShowDialog() == DialogResult.OK)
{
_textSrcFile.Text = ofn.FileName;
_sourceFile = _textSrcFile.Text;
}
}
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Next, add an event handler to the _buttonBrowseTarget Click event to handle browsing for the output path where the extracted video frames will be saved. Code this event handler as follows:
Private Sub _buttonBrowseTarget_Click(ByVal sender As Object, ByVal e As EventArgs) Handles _buttonBrowseTarget.Click
Dim fbd As FolderBrowserDialog = New FolderBrowserDialog()
fbd.SelectedPath = _targetPath
fbd.ShowNewFolderButton = True
fbd.Description = "Frames Output Folder"
fbd.RootFolder = Environment.SpecialFolder.MyComputer
If fbd.ShowDialog() = DialogResult.OK Then
_targetPath = fbd.SelectedPath
_textTargetPath.Text = _targetPath
End If
End Sub
private void _buttonBrowseTarget_Click(object sender, EventArgs e)
{
FolderBrowserDialog fbd = new FolderBrowserDialog();
fbd.SelectedPath = _targetPath;
fbd.ShowNewFolderButton = true;
fbd.Description = "Frames Output Folder";
fbd.RootFolder = Environment.SpecialFolder.MyComputer;
if (fbd.ShowDialog() == DialogResult.OK)
{
_targetPath = fbd.SelectedPath;
_textTargetPath.Text = _targetPath;
}
}
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Finally, add an event handler to the _buttonConvert Click event to perform the conversion/extraction. Code this event handler as follows:
Private Sub _buttonConvert_Click(ByVal sender As Object, ByVal e As EventArgs) Handles _buttonConvert.Click
Try
ExtractFrames()
_buttonBrowseSrc.Enabled = False
_buttonBrowseTarget.Enabled = False
_buttonConvert.Enabled = False
Catch ex As Exception
MessageBox.Show(Me, ex.Message)
End Try
End Sub
private void _buttonConvert_Click(object sender, EventArgs e)
{
try
{
ExtractFrames();
_buttonBrowseSrc.Enabled = false;
_buttonBrowseTarget.Enabled = false;
_buttonConvert.Enabled = false;
}
catch (Exception ex)
{
MessageBox.Show(this, ex.Message);
}
}
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Now, with all the forms, elements, and events setup out of the way, we can write the code behind the ExtractFrames method. This is where the real work of starting the conversion, looping through all the sample frames and extracting them to bitmap files is done. Add the following methods and code as follows:
Public Sub ExtractFrames()
' input file and output files
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 = _sourceFile
' 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()
' get the sample times
msFrame.GetTime(sampleStart, sampleStop)
' create the file name for this frame bitmap
sampleFileName = String.Format("{0}\Frame_{1}-{2}.bmp", _targetPath, 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
Loop
Catch e1 As Exception
' fail!
End Try
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 void ExtractFrames()
{
// input file and output files
string sampleFileName;
// 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 = _sourceFile;
// set the preview
_convertctrl.Preview = true;
// create a new sample target
SampleTarget st = new SampleTarget();
// set the target media type for the video stream
MediaType mtTarget = new MediaType();
mtTarget.Type = Constants.MEDIATYPE_Video;
mtTarget.SubType = 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();
MediaSample msFrame = st.GetSample(1000);
long sampleStart, sampleStop;
while (msFrame != null)
{
// get the sample target's connected media type
MediaType mtSample = st.GetConnectedMediaType();
// get the sample times
msFrame.GetTime(out sampleStart, out sampleStop);
// create the file name for this frame bitmap
sampleFileName = string.Format("{0}\\Frame_{1}-{2}.bmp", _targetPath, 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 (COMException cex)
{
// if we have reached the end of stream we are finished
if (cex.ErrorCode == (int)ErrorCode.VFW_E_SAMPLE_REJECTED_EOS
|| cex.ErrorCode == (int)ErrorCode.VFW_E_WRONG_STATE)
break;
else if (cex.ErrorCode == (int)ErrorCode.VFW_E_TIMEOUT)
continue;
else
throw cex;
}
}
}
catch (Exception)
{
// fail!
}
}
private Bitmap WriteSampleBitmap(string outFile, MediaSample ms, MediaType mt)
{
// get the video information
VideoInfoHeader vih = mt.GetVideoFormatData();
// create a bitmap to hold the sample and copy it
Bitmap bmp = new Bitmap(vih.bmiHeader.biWidth, vih.bmiHeader.biHeight, FormatFromBitCount(vih.bmiHeader.biBitCount));
BitmapData bmpData = 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;
}
private PixelFormat FormatFromBitCount(int bitCount)
{
switch (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;
}
throw new Exception("Unrecognized bit count");
}
private int GetBitmapSize(Bitmap bmp, int bitCount)
{
int pixelSize = (int)Math.Log((double)bitCount);
return (bmp.Width * pixelSize + pixelSize & ~3) * bmp.Height;
}
private int GetBitmapScanRowSize(int bmpSize, int stride, int width)
{
return bmpSize / (stride / width);
}
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Now you are ready to Build, and Run the program to test it. Use the Source... button to browse for the source video file and then select the target output folder for frames by using the [...] browse button. Next click the Extract button to perform the conversion/extraction and then open the output folder to view the extracted bitmap files.
