Creating a LEADTOOLS Multimedia Capture Application using LEADTOOLS DVR Components

Perform the following steps to create and run a multimedia capture DVR application using the LEADTOOLS Multimedia CaptureCtrl and PlayCtrl controls and DVR components of the LEADTOOLS MPEG-2 Transport module.

Start Visual Studio.
Choose File->New->Project... from the menu.
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.
Type the project name as "Multimedia DVR" 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.
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. Also, right-click the "References" folder, and select "Add Reference..." from the context menu. In the "Add Reference" dialog box, select the "COM" tab and select:
- LEAD MPEG2 Transport Demultiplexer Library
- LEAD DVR Sink Library
- LEAD MPEG-2 Encoder Filter Library
Note: The above COM objects must be registered; in case they were not; using regsvr32. For more information, refer to DirectShow Registry-free Activation.

Next click OK.

Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and drag a CaptureCtrl control and a PlayCtrl control on the form. After adding it to the form, set the following properties on the controls:

Property	Value
Name	_capturectrl
Anchor	Top, Bottom, Left
Name	_playctrl
Anchor	Top, Bottom, Right
AutoStart	false

Go to the toolbox (View->Toolbox) and drag a TrackBar control on the form (below the play control) and set the following properties:

Property Value

Name _track

Anchor Bottom, Left, Right

Property	Value
Name	_track
Anchor	Bottom, Left, Right

Go to the toolbox (View->Toolbox) and drag two Button controls to the bottom of the form and set the following properties:

Property	Value
Name	_buttonCapture
Text	Capture
Anchor	Bottom, Right
Name	_buttonPlay
Text	Play
Anchor	Bottom, Right

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:

vb 
Imports Leadtools.Multimedia 
Imports LMMpgDmxTLib 
Imports LMDVRSinkLib 
Imports LMMPEG2EncoderLib

using Leadtools.Multimedia; 
using LMMpgDmxTLib; 
using LMDVRSinkLib; 
using LMMPEG2EncoderLib;

Declare the following private variables:

vb 
Private Const SLIDER_MAX As Integer = 10000 
Private _targetFile As String 
Private _targetFolder As String 
Private _capturing As Boolean 
Private _mpegDemux As LMMpgDmxT 
Private _dvrSink As ILMDVRSink 
Private _firstPTS As Double 
Private _lastPTS As Double

private const int SLIDER_MAX = 10000; 
private string _targetFile; 
private string _targetFolder; 
private bool _capturing; 
private LMMpgDmxT _mpegDemux; 
private ILMDVRSink _dvrSink; 
private double _firstPTS; 
private double _lastPTS;

Add an event handler to the Form1 Load event and code it as follows:

vb 
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
  If _capturectrl.VideoDevices.Count = 0 Then 
     Throw New Exception("No capture devices available") 
  End If 
                  
  If _capturectrl.VideoDevices("Analog") Is Nothing Then 
     Throw New Exception("No Analog TV capture devices available") 
  End If 
                  
  _capturectrl.VideoDevices("Analog").Selected = True 
  _capturectrl.UseVideoDeviceAudio = True 
                  
  _capturing = False 
  _targetFolder = Path.Combine(Directory.GetCurrentDirectory(), "DVRFolder") 
  If (Not Directory.Exists(_targetFolder)) Then 
     Directory.CreateDirectory(_targetFolder) 
  End If 
                  
  _targetFile = "capture.lbl" 
                  
  _capturectrl.PreviewTap = CapturePreviewTap.Source 
  _capturectrl.Preview = True 
  _capturectrl.PreviewSource = CapturePreview.Video 
End Sub

private void Form1_Load(object sender, System.EventArgs e) 
{ 
   if (_capturectrl.VideoDevices.Count == 0) 
      throw new Exception("No capture devices available"); 
                 
   if (_capturectrl.VideoDevices["Analog"] == null) 
      throw new Exception("No Analog TV capture devices available"); 
                 
   _capturectrl.VideoDevices["Analog"].Selected = true; 
   _capturectrl.UseVideoDeviceAudio = true; 
                  
   _capturing = false; 
   _targetFolder = Path.Combine(Directory.GetCurrentDirectory(), "DVRFolder"); 
   if (!Directory.Exists(_targetFolder)) 
      Directory.CreateDirectory(_targetFolder); 
                  
   _targetFile = "capture.lbl"; 
                  
   _capturectrl.PreviewTap = CapturePreviewTap.Source; 
   _capturectrl.Preview = true; 
   _capturectrl.PreviewSource = CapturePreview.Video; 
}

Add the following helper methods as follows:

vb 
Private Function IsStreaming() As Boolean 
   Return (_capturectrl.VideoCaptureStreamType = Leadtools.Multimedia.Constants.MEDIATYPE_Stream) 
End Function 
                  
Private Function PTSToSliderPosition(ByVal curPTS As Double) As Integer 
   Dim retVal As Integer = 0 
   If curPTS <= _firstPTS Then 
      retVal = 0 
   ElseIf curPTS >= _lastPTS Then 
      retVal = SLIDER_MAX 
   Else 
      retVal = CInt(((curPTS - _firstPTS) * SLIDER_MAX) / (_lastPTS - _firstPTS) + 0.5) 
   End If 
                  
   Return retVal 
End Function 
                  
Private Function SliderPositionToPTS(ByVal nPos As Integer) As Double 
   Return _firstPTS + CDbl(nPos) * (_lastPTS - _firstPTS) / CDbl(SLIDER_MAX) 
End Function

private bool IsStreaming() 
{ 
   return (_capturectrl.VideoCaptureStreamType == Constants.MEDIATYPE_Stream); 
} 
                  
private int PTSToSliderPosition(double curPTS) 
{ 
   int retVal = 0; 
   if (curPTS <= _firstPTS) 
      retVal = 0; 
   else if (curPTS >= _lastPTS) 
      retVal = SLIDER_MAX; 
   else 
      retVal = (int)(((curPTS - _firstPTS) * SLIDER_MAX) / (_lastPTS - _firstPTS) + 0.5); 
                  
   return retVal; 
} 
                  
private double SliderPositionToPTS(int nPos) 
{ 
   return _firstPTS + (double)nPos * (_lastPTS - _firstPTS) / (double)SLIDER_MAX; 
}

Add an event handler to the _capturectrl Progress event and code it as follows:

vb 
Private Sub _capturectrl_Progress(ByVal sender As Object, ByVal e As ProgressEventArgs) Handles _capturectrl.Progress 
  If Not _mpegDemux Is Nothing Then 
     _mpegDemux.RefreshPosition(0) 
                  
     Dim curPTS As Double = _mpegDemux.CurrentStreamPTS 
     _firstPTS = _mpegDemux.FirstStreamPTS 
     _lastPTS = _mpegDemux.LastStreamPTS 
                  
     If curPTS < _firstPTS AndAlso _playctrl.State = PlayState.Paused Then 
        _playctrl.Run() 
     End If 
  End If 
End Sub

private void _capturectrl_Progress(object sender, ProgressEventArgs e) 
{ 
   if (_mpegDemux != null) 
   { 
      _mpegDemux.RefreshPosition(0); 
                  
      double curPTS = _mpegDemux.CurrentStreamPTS; 
      _firstPTS = _mpegDemux.FirstStreamPTS; 
      _lastPTS = _mpegDemux.LastStreamPTS; 
                  
      if (curPTS < _firstPTS && _playctrl.State == PlayState.Paused) 
         _playctrl.Run(); 
   } 
}

Add an event handler to the _playctrl TrackingPositionChanged event and code it as follows:

vb 
Private Sub _playctrl_TrackingPositionChanged(ByVal sender As System.Object, ByVal e As TrackingPositionChangedEventArgs) Handles _playctrl.TrackingPositionChanged 
   If Not _mpegDemux Is Nothing Then 
      _mpegDemux.RefreshPosition(0) 
                 
      Dim curPTS As Double = _mpegDemux.CurrentStreamPTS 
      _firstPTS = _mpegDemux.FirstStreamPTS 
      _lastPTS = _mpegDemux.LastStreamPTS 
                 
      _track.Value = PTSToSliderPosition(curPTS) 
   End If 
End Sub

private void _playctrl_TrackingPositionChanged(object sender, TrackingPositionChangedEventArgs e) 
{ 
   if (_mpegDemux != null) 
   { 
      _mpegDemux.RefreshPosition(0); 
                 
      double curPTS = _mpegDemux.CurrentStreamPTS; 
      _firstPTS = _mpegDemux.FirstStreamPTS; 
      _lastPTS = _mpegDemux.LastStreamPTS; 
                 
      _track.Value = PTSToSliderPosition(curPTS); 
   } 
}

Add an event handler to the _track Scroll event and code it as follows:

vb 
Private Sub _track_Scroll(ByVal sender As System.Object, ByVal e As EventArgs) Handles _track.Scroll 
   If Not _mpegDemux Is Nothing Then 
      Dim ptsPos As Double = SliderPositionToPTS(_track.Value) 
      _mpegDemux.CurrentStreamPTS = ptsPos 
   End If 
End Sub

private void _track_Scroll(object sender, EventArgs e) 
{ 
   if (_mpegDemux != null) 
   { 
      double ptsPos = SliderPositionToPTS(_track.Value); 
      _mpegDemux.CurrentStreamPTS = ptsPos; 
   } 
}

Add an event handler to the _capturectrl Complete event and code it as follows:

vb 
Private Sub _capturectrl_Complete(ByVal sender As System.Object, ByVal e As EventArgs) Handles _capturectrl.Complete 
   MessageBox.Show("Capture Complete") 
   _buttonCapture.Enabled = true 
End Sub

private void _capturectrl_Complete(object sender, EventArgs e) 
{ 
   MessageBox.Show("Capture Complete"); 
   _buttonCapture.Enabled = true; 
}

Add an event handler to the _playctrl StateChanged event and code it as follows:

vb 
Private Sub _playctrl_StateChanged(ByVal sender As Object, ByVal e As StateChangedEventArgs) Handles _playctrl.StateChanged 
   If e.state = PlayState.Running Then 
      _mpegDemux = Nothing 
      _mpegDemux = TryCast(_playctrl.GetSubObject(PlayObject.Splitter), LMMpgDmxT) 
   End If 
End Sub

private void _playctrl_StateChanged(object sender, StateChangedEventArgs e) 
{ 
   if (e.state == PlayState.Running) 
   { 
      _mpegDemux = null; 
      _mpegDemux = _playctrl.GetSubObject(PlayObject.Splitter) as LMMpgDmxT; 
   } 
}

Add an event handler to the _buttonCapture Click event and code it as follows:

vb 
Private Sub _buttonCapture_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _buttonCapture.Click 
   Try 
      If _capturing = True Then 
         _capturectrl.StopCapture() 
      Else 
         Dim recVideoComp As String = String.Empty 
         Dim recAudioComp As String = String.Empty 
                 
         If IsStreaming() Then 
            _capturectrl.TargetFormats.DVR.Selected = True 
            _capturectrl.TargetFormat = TargetFormatType.DVR 
            _capturectrl.VideoCompressors.Selection = -1 
            _capturectrl.AudioCompressors.Selection = -1 
         Else 
            _capturectrl.TargetFormats.DVRTransport.Selected = True 
            recVideoComp = _capturectrl.TargetFormats.DVRTransport.RecommendedVideoCompressor 
            recAudioComp = _capturectrl.TargetFormats.DVRTransport.RecommendedAudioCompressor 
            _capturectrl.TargetFormat = TargetFormatType.DVRTransport 
            If recVideoComp <> String.Empty Then 
               _capturectrl.VideoCompressors(recVideoComp).Selected = True 
            End If 
            If recAudioComp <> String.Empty Then 
               _capturectrl.AudioCompressors(recAudioComp).Selected = True 
            End If 
                              
            If _capturectrl.VideoCompressors.Mpeg2.Selected = True Then 
           Dim mpeg2Encoder As LMMPEG2Encoder = TryCast(_capturectrl.GetSubObject(CaptureObject.VideoCompressor), LMMPEG2Encoder) 
           If Not mpeg2Encoder Is Nothing Then 
             mpeg2Encoder.EncodingThreads = eMpeg2EncodingThreads.MPEG2_THREAD_AUTO 
             mpeg2Encoder.VideoFormat = eMPEG2VIDEOFORMAT.MPEG2_VF_NTSC 
             Marshal.ReleaseComObject(mpeg2Encoder) 
           End If 
         End If 
         End If 
                 
         _capturectrl.Preview = True 
         _capturectrl.TargetFile = _targetFile 
                 
         _capturectrl.ReadyCapture(CaptureMode.VideoAndAudio Or CaptureMode.InhibitRun) 
         _dvrSink = TryCast(_capturectrl.GetSubObject(CaptureObject.Sink), ILMDVRSink) 
                 
         If Not _dvrSink Is Nothing Then 
            Dim dBuffSize As Double = 102400000 ' 100 MB 
            Dim lFileCount As Integer = 8 ' 8 buffer files 
            _dvrSink.StartChangingAttributes() 
                 
            _dvrSink.FolderCount = 1 
            _dvrSink.FolderName(0) = _targetFolder 
            _dvrSink.SetBufferSize(0, lFileCount, dBuffSize) 
                 
            _dvrSink.StopChangingAttributes(False) 
            Dim bufferFolder As String = _dvrSink.BaseName 
         End If 
                 
         _capturectrl.RunCapture() 
         _buttonCapture.Enabled = False 
         _capturing = True 
      End If 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub

private void _buttonCapture_Click(object sender, System.EventArgs e) 
{ 
   try 
   { 
      if (_capturing == true) 
         _capturectrl.StopCapture(); 
      else 
      { 
         string recVideoComp = string.Empty; 
         string recAudioComp = string.Empty; 
                 
         if (IsStreaming()) 
         { 
            _capturectrl.TargetFormats.DVR.Selected = true; 
            _capturectrl.TargetFormat = TargetFormatType.DVR; 
            _capturectrl.VideoCompressors.Selection = -1; 
            _capturectrl.AudioCompressors.Selection = -1; 
         } 
         else 
         { 
            _capturectrl.TargetFormats.DVRTransport.Selected = true; 
            recVideoComp = _capturectrl.TargetFormats.DVRTransport.RecommendedVideoCompressor; 
            recAudioComp = _capturectrl.TargetFormats.DVRTransport.RecommendedAudioCompressor; 
            _capturectrl.TargetFormat = TargetFormatType.DVRTransport; 
            if (recVideoComp != string.Empty) 
               _capturectrl.VideoCompressors[recVideoComp].Selected = true; 
            if (recAudioComp != string.Empty) 
               _capturectrl.AudioCompressors[recAudioComp].Selected = true; 
                                 
            if (_capturectrl.VideoCompressors.Mpeg2.Selected == true) 
            { 
              LMMPEG2Encoder mpeg2Encoder = _capturectrl.GetSubObject(CaptureObject.VideoCompressor) as LMMPEG2Encoder; 
              if (mpeg2Encoder != null) 
              { 
                 mpeg2Encoder.EncodingThreads = eMpeg2EncodingThreads.MPEG2_THREAD_AUTO; 
                 mpeg2Encoder.VideoFormat = eMPEG2VIDEOFORMAT.MPEG2_VF_NTSC; 
                 Marshal.ReleaseComObject(mpeg2Encoder); 
              } 
            } 
         } 
                 
         _capturectrl.Preview = true; 
         _capturectrl.TargetFile = _targetFile; 
                 
         _capturectrl.ReadyCapture(CaptureMode.VideoAndAudio |   CaptureMode.InhibitRun); 
         _dvrSink = _capturectrl.GetSubObject(CaptureObject.Sink) as ILMDVRSink; 
                 
         if (_dvrSink != null) 
         { 
            double dBuffSize = 102400000;  // 100 MB 
            int lFileCount = 8;           // 8 buffer files 
            _dvrSink.StartChangingAttributes(); 
                 
            _dvrSink.FolderCount = 1; 
            _dvrSink.set_FolderName(0, _targetFolder); 
            _dvrSink.SetBufferSize(0, lFileCount, dBuffSize); 
                 
            _dvrSink.StopChangingAttributes(false); 
            string bufferFolder = _dvrSink.BaseName; 
         } 
                 
         _capturectrl.RunCapture(); 
         _buttonCapture.Enabled = false; 
         _capturing = true; 
      } 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}

Add an event handler to the _buttonPlay Click event and code it as follows:

vb 
Private Sub _buttonPlay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _buttonPlay.Click 
   Try 
      _mpegDemux = Nothing 
      _playCtrl.ResetSource() 
                 
      _playCtrl.PreferredMPEG2Splitter = Leadtools.Multimedia.Constants.Filter_MPEG2_Transport_Demux 
      _playctrl.SourceFile = Path.Combine(_targetFolder, _targetFile) 
      _playctrl.Run 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub

private void _buttonPlay_Click(object sender, System.EventArgs e) 
{ 
   try 
   { 
      _mpegDemux = null; 
      _playCtrl.ResetSource(); 
                 
      _playCtrl.PreferredMPEG2Splitter = Constants.Filter_MPEG2_Transport_Demux; 
      _playctrl.SourceFile = Path.Combine(_targetFolder, _targetFile); 
      _playctrl.Run(); 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(this, ex.Message); 
   } 
}