IsPreviewTapSupported Method

Summary

Determines whether a specific preview tap for the preview source is available.

Syntax
C#
VB
C++
public virtual bool IsPreviewTapSupported( 
   CapturePreview source, 
   CapturePreviewTap tap 
) 
Public Overridable Function IsPreviewTapSupported( _ 
   ByVal source As CapturePreview, _ 
   ByVal tap As CapturePreviewTap _ 
) As Boolean 
public: 
virtual bool IsPreviewTapSupported(  
   CapturePreview source, 
   CapturePreviewTap tap 
)  

Parameters

source
The preview source for which to determine whether a preview tap is supported.

tap
The preview tap type to check if it is supported or not.

Return Value

true if the preview tap is supported; false, otherwise.

Remarks

See PreviewTap for more information on the PreviewTap object.

Example
C#
VB
using Leadtools; 
using Leadtools.Multimedia; 
using LeadtoolsMultimediaExamples.Fixtures; 
 
public bool _result = false; 
public CaptureCtrlForm _form = new CaptureCtrlForm(); 
 
public void CapturePreviewExample() 
{ 
   // 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; 
   } 
} 
 
public void CaptureCtrl_Complete(object sender, EventArgs e) 
{ 
   // set result 
   _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 CapturePreviewExample() 
   ' 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 
 
Public Sub CaptureCtrl_Complete(ByVal sender As Object, ByVal e As EventArgs) 
   ' set result 
   _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