Capturing Using a TV Tuner

Take the following steps to create and run a multimedia TV tuner capture application using the LEADTOOLS Media Foundation CaptureCtrl control.

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 TV Tuner Capture" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK.
In the "Solution Explorer" window, right-click on the "References" folder, and select "Add Reference..." from the context menu. In the "Add Reference" dialog box, select the ".NET" tab and select Leadtools.MediaFoundation and click OK.

Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and drag and drop a CaptureCtrl control on the form. NOTE: If you do not have CaptureCtrl in your toolbox, select Tools->Choose Toolbox Items from the menu. Click Browse and then select Leadtools.MediaFoundation.dll from "<LEADTOOLS_INSTALLDIR>\Bin\Dotnet4\Win32" and then click Open and then click OK. After adding it to the form, set the following properties on the capture control:

Property	Value
Name	_capturectrl
Anchor	Top, Bottom, Left, Right

Go to the toolbox (View->Toolbox) and drag and drop a ProgressBar control (to be used to display capture progress) on the form (below the capture control) and set the following properties:

Property Value

Name _progress

Anchor Bottom, Left, Right

Property	Value
Name	_progress
Anchor	Bottom, Left, Right

Go to the toolbox (View->Toolbox) and drag and drop 4 Button controls on the bottom of the form (for Capture, Channel Up and Channel Down) and set the following properties:

Property	Value
Name	_buttonCapture
Text	Capture
Anchor	Bottom, Right
Name	_buttonChannelUp
Text	Up
Anchor	Bottom, Right
Name	_buttonChannelDown
Text	Down
Anchor	Bottom, Right

Go to the toolbox (View->Toolbox) and drag and drop a Label control, a Text control, another Label control and a ProgressBar control on the bottom left of the form (for a "Channel:" label, a channel text box, a "Signal:" label and a signal strength meter) and set the following properties:

Property	Value
Name	label1
Text	Channel:
Anchor	Bottom, Left
Name	_textChannel
Anchor	Bottom, Left
Locked	True
ReadOnly	True
TextAlign	Center
Name	label2
Text	Signal:
Anchor	Bottom, Left
Name	_signal
Anchor	Bottom, Left

Switch Form1 to code view (right-click Form1 in the solution explorer then select View Code) and add the following lines at the beginning of the file:

using System.Runtime.InteropServices; 
using Leadtools.MediaFoundation;

vb 
Imports System.Runtime.InteropServices 
Imports Leadtools.MediaFoundation

Declare the following private variables:

private string _targetFile; 
private int _captureTime;

vb 
Private _targetFile As String 
Private _captureTime As Integer

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

private void Form1_Load(object sender, 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; 
                    
   _capturectrl..TargetFormats.Selection = TargetFormatType.MP4; 
                    
   _targetFile = @"capture.mp4"; 
   _captureTime = 30; 
   _capturectrl.PreviewSource = CapturePreview.Video; 
   _capturectrl.Preview = true; 
   DisplayChannelAndSignal(); 
}

vb 
Private Sub Form1_Load(ByVal sender As Object, ByVal e As 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..TargetFormats.Selection = TargetFormatType.MP4 
                    
   _targetFile = "capture.mp4" 
   _captureTime = 30 
   _capturectrl.PreviewSource = CapturePreview.Video 
   _capturectrl.Preview = True 
   DisplayChannelAndSignal() 
End Sub

Add the following helper methods as follows:

private void DisplayChannelAndSignal() 
{ 
   if (_capturectrl.TVTuner != null) 
   { 
      int currChannel = _capturectrl.TVTuner.Channel; 
      _textChannel.Text = currChannel.ToString(); 
      TunerSignalStrength signal = _capturectrl.TVTuner.SignalPresent; 
      switch (signal) 
      { 
         case TunerSignalStrength.NoSignal: 
            _signal.Value = 0; 
            break; 
         case TunerSignalStrength.HasNoSignalStrength: 
            _signal.Value = 10; 
            break; 
         case TunerSignalStrength.SignalPresent: 
            _signal.Value = 100; 
            break; 
      } 
   } 
} 
private void ChangeChannel(bool up) 
{ 
   int chanMin = _capturectrl.TVTuner.ChannelMin; 
   int chanMax = _capturectrl.TVTuner.ChannelMax; 
   int currChannel = _capturectrl.TVTuner.Channel; 
   int currVideoChannel = _capturectrl.TVTuner.VideoSubChannel; 
   if (up) 
   { 
      if (currChannel == chanMax) 
         currChannel = chanMin; 
      else 
         currChannel++; 
   } 
   else 
   { 
      if (currChannel == chanMin) 
         currChannel = chanMax; 
      else 
         currChannel--; 
   } 
   _capturectrl.TVTuner.SetChannel(currChannel, -1, -1); 
   DisplayChannelAndSignal(); 
}

vb 
Private Sub DisplayChannelAndSignal() 
   If Not _capturectrl.TVTuner Is Nothing Then 
      Dim currChannel As Integer = _capturectrl.TVTuner.Channel 
      _textChannel.Text = currChannel.ToString() 
      Dim signal As TunerSignalStrength = _capturectrl.TVTuner.SignalPresent 
      Select Case signal 
         Case TunerSignalStrength.NoSignal 
            _signal.Value = 0 
         Case TunerSignalStrength.HasNoSignalStrength 
            _signal.Value = 10 
         Case TunerSignalStrength.SignalPresent 
            _signal.Value = 100 
      End Select 
   End If 
End Sub 
Private Sub ChangeChannel(ByVal up As Boolean) 
   Dim chanMin As Integer = _capturectrl.TVTuner.ChannelMin 
   Dim chanMax As Integer = _capturectrl.TVTuner.ChannelMax 
   Dim currChannel As Integer = _capturectrl.TVTuner.Channel 
   Dim currVideoChannel As Integer = _capturectrl.TVTuner.VideoSubChannel 
   If up Then 
      If currChannel = chanMax Then 
         currChannel = chanMin 
      Else 
         currChannel += 1 
      End If 
   Else 
      If currChannel = chanMin Then 
         currChannel = chanMax 
      Else 
         currChannel -= 1 
      End If 
   End If 
   _capturectrl.TVTuner.SetChannel(currChannel, -1, -1) 
   DisplayChannelAndSignal() 
End Sub

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

private void _capturectrl_Progress(object sender, ProgressEventArgs e) 
{ 
   _progress.Value = (int)((_progress.Maximum * e.time) / (_captureTime * 1000)); 
}

vb 
Private Sub _capturectrl_Progress(ByVal sender As System.Object, ByVal e As ProgressEventArgs) Handles _capturectrl.Progress 
   _progress.Value = CInt((_progress.Maximum * e.time) / (_captureTime * 1000)) 
End Sub

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

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

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

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

private void _buttonChannelUp_Click(object sender, EventArgs e) 
{ 
   if (_capturectrl.TVTuner != null) 
   { 
      ChangeChannel(true); 
   } 
}

vb 
Private Sub _buttonChannelUp_Click(ByVal sender As Object, ByVal e As EventArgs) Handles _buttonChannelUp.Click 
   If Not _capturectrl.TVTuner Is Nothing Then 
      ChangeChannel(True) 
   End If 
End Sub

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

private void _buttonChannelDown_Click(object sender, EventArgs e) 
{ 
   if (_capturectrl.TVTuner != null) 
   { 
      ChangeChannel(false); 
   } 
}

vb 
Private Sub _buttonChannelDown_Click(ByVal sender As Object, ByVal e As EventArgs) Handles _buttonChannelDown.Click 
   If Not _capturectrl.TVTuner Is Nothing Then 
      ChangeChannel(False) 
   End If 
End Sub

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

private void _buttonCapture_Click(object sender, System.EventArgs e) 
{ 
   try 
   { 
      _capturectrl.Preview = true; 
      _capturectrl.TargetFile = _targetFile; 
      _capturectrl.UseTimeLimit = true; 
      _capturectrl.TimeLimit = _captureTime; 
                       
      _capturectrl.StartCapture(CaptureMode.Video); 
      _buttonCapture.Enabled = false; 
   } 
   catch (Exception ex) 
   { 
      MessageBox.Show(ex.Message); 
   } 
}

vb 
Private Sub _buttonCapture_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _buttonCapture.Click 
   Try 
      _capturectrl.Preview = True 
      _capturectrl.TargetFile = _targetFile 
      _capturectrl.UseTimeLimit = True 
      _capturectrl.TimeLimit = _captureTime 
                       
      _capturectrl.StartCapture(CaptureMode.Video) 
      _buttonCapture.Enabled = False 
   Catch ex As Exception 
      MessageBox.Show(ex.Message) 
   End Try 
End Sub