PreviewTap Property

Summary

Gets or sets the tap location from which the preview output originates.

Syntax
C#
VB
C++
public virtual CapturePreviewTap PreviewTap { get; set; } 
Public Overridable Property PreviewTap As CapturePreviewTap 
public: 
virtual property CapturePreviewTap PreviewTap { 
   CapturePreviewTap get(); 
   void set (    CapturePreviewTap ); 
} 

Property Value

A CapturePreviewTap value representing the preview tap location.

Remarks

The value is one of the CapturePreviewTap enumeration values. Assignment can raise an error exception. For more information, refer to the Error Codes.

Example
C#
VB
using Leadtools; 
using Leadtools.Multimedia; 
using LeadtoolsMultimediaExamples.Fixtures; 
 
public bool _result = false; 
public CaptureCtrlForm _form = new CaptureCtrlForm(); 
 
public void IsModeAvailableExample() 
{ 
   // reference the capture control 
   CaptureCtrl capturectrl = _form.CaptureCtrl; 
 
   // output file for processor settings 
   string outFile = Path.Combine(LEAD_VARS.MediaDir, "CaptureCtrl_IsModeAvailableExample.avi"); 
 
   try 
   { 
      // try to find a USB camera 
      if (capturectrl.VideoDevices["USB"] == null) 
         throw new Exception("No USB video device available"); 
 
      capturectrl.VideoDevices["USB"].Selected = true; 
 
      // try to find a USB audio device 
      if (capturectrl.AudioDevices["USB"] == null) 
         throw new Exception("No USB audio device available"); 
 
      capturectrl.AudioDevices["USB"].Selected = true; 
 
      // set MPEG2 as the video compressor 
      capturectrl.VideoCompressors.Mpeg2.Selected = true; 
 
      // set AC3 as the audio compressor 
      capturectrl.AudioCompressors.AC3.Selected = true; 
 
      // set the target output file 
      capturectrl.TargetFile = outFile; 
 
      // set the target output format 
      capturectrl.TargetFormat = TargetFormatType.AVI; 
 
      // check whether we can capture video 
      if (capturectrl.IsModeAvailable(CaptureMode.VideoAndAudio)) 
      { 
         capturectrl.FrameRate = 5;       // 5 frames per second  
         capturectrl.UseFrameRate = true; 
         capturectrl.TimeLimit = 10;      // just 10 seconds of capture time 
         capturectrl.UseTimeLimit = true; 
 
         // check to see if we can preview compressed output 
         if (capturectrl.IsPreviewTapSupported(CapturePreview.Video, CapturePreviewTap.Compressor)) 
         { 
            // enable preview 
            capturectrl.Preview = true; 
 
            // enable preview video 
            capturectrl.PreviewSource = CapturePreview.Video; 
 
            // set the preview tap location 
            capturectrl.PreviewTap = CapturePreviewTap.Compressor; 
         } 
 
         // subscribe to the complete event 
         capturectrl.Complete += new EventHandler(CaptureCtrl_Complete); 
 
         // start the capture process 
         capturectrl.StartCapture(CaptureMode.VideoAndAudio); 
 
         // 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. 
         while (capturectrl.State == CaptureState.Running) 
            Application.DoEvents(); 
      } 
   } 
   catch (Exception) 
   { 
      _result = false; 
   } 
} 
 
void CaptureCtrl_Complete(object sender, EventArgs e) 
{ 
   _result = true; 
} 
 
static class LEAD_VARS 
{ 
   public const string MediaDir = @"C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 20\Media"; 
} 
Imports Leadtools 
Imports Leadtools.Multimedia 
Imports LeadtoolsMultimediaExamples.Fixtures 
 
Public _result As Boolean = False 
Public _form As CaptureCtrlForm = New CaptureCtrlForm() 
 
Public Sub IsModeAvailableExample() 
   ' reference the capture control 
   Dim capturectrl As CaptureCtrl = _form.CaptureCtrl 
 
   ' output file for processor settings 
   Dim outFile As String = Path.Combine(LEAD_VARS.MediaDir, "CaptureCtrl_IsModeAvailableExample.avi") 
 
   Try 
      ' try to find a USB camera 
      If capturectrl.VideoDevices("USB") Is Nothing Then 
         Throw New Exception("No USB video device available") 
      End If 
 
      capturectrl.VideoDevices("USB").Selected = True 
 
      ' try to find a USB audio device 
      If capturectrl.AudioDevices("USB") Is Nothing Then 
         Throw New Exception("No USB audio device available") 
      End If 
 
      capturectrl.AudioDevices("USB").Selected = True 
 
      ' set MPEG2 as the video compressor 
      capturectrl.VideoCompressors.Mpeg2.Selected = True 
 
      ' set AC3 as the audio compressor 
      capturectrl.AudioCompressors.AC3.Selected = True 
 
      ' set the target output file 
      capturectrl.TargetFile = outFile 
 
      ' set the target output format 
      capturectrl.TargetFormat = TargetFormatType.AVI 
 
      ' check if we have can capture video 
      If capturectrl.IsModeAvailable(CaptureMode.VideoAndAudio) Then 
         capturectrl.FrameRate = 5 ' 5 frames per second 
         capturectrl.UseFrameRate = True 
         capturectrl.TimeLimit = 10 ' just 10 seconds of capture time 
         capturectrl.UseTimeLimit = True 
 
         ' check to see if we can preview compressed output 
         If capturectrl.IsPreviewTapSupported(CapturePreview.Video, CapturePreviewTap.Compressor) Then 
            ' enable preview 
            capturectrl.Preview = True 
 
            ' enable preview video 
            capturectrl.PreviewSource = CapturePreview.Video 
 
            ' set the preview tap location 
            capturectrl.PreviewTap = CapturePreviewTap.Compressor 
         End If 
 
         ' subscribe to the complete event 
         AddHandler capturectrl.Complete, AddressOf CaptureCtrl_Complete 
 
         ' start the capture process 
         capturectrl.StartCapture(CaptureMode.VideoAndAudio) 
 
         ' 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 If 
   Catch e1 As Exception 
      _result = False 
   End Try 
End Sub 
 
Private Sub CaptureCtrl_Complete(ByVal sender As Object, ByVal e As EventArgs) 
   _result = True 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const MediaDir As String = "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 20\Media" 
End Class 
Requirements

Target Platforms

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Leadtools.Multimedia Assembly