LEADTOOLS Multimedia (Leadtools.Multimedia assembly)
LEAD Technologies, Inc

NumberOfLines Property

Example 





Gets the number of scan lines in the video signal.
Syntax
public int NumberOfLines {get;}
'Declaration
 
Public ReadOnly Property NumberOfLines As Integer
'Usage
 
Dim instance As AnalogVideoDecoder
Dim value As Integer
 
value = instance.NumberOfLines
public int NumberOfLines {get;}
 get_NumberOfLines(); 
public:
property int NumberOfLines {
   int get();
}

Property Value

A value indicating the number of scan lines.
Remarks

This property is updated with the number of scan lines in the video signal. The retrieved value is generally 525 lines for NTSC and 625 lines for PAL or SECAM.

For more detailed information, refer to the Microsoft documentation for IAMAnalogVideoDecoder.get_NumberOfLines.

Example
Copy CodeCopy Code  
Public _result As Boolean = False
      Public _form As CaptureCtrlForm = New CaptureCtrlForm()
      Public Sub AvailableTVFormatsExample()
         Try
            ' reference the forms capture control
            Dim capturectrl As CaptureCtrl = _form.CaptureCtrl

            Dim outFile As String = Path.Combine(LEAD_VARS.MediaDir, "AnalogVideoDecoder_AvailableTVFormatsExample.avi")
            Dim lines As Integer = 0
            Dim allResults As Boolean = True

            ' select the first device with analog in it's name
            ' Replace "Analog" with your tuner device name
            If capturectrl.VideoDevices("Analog") Is Nothing Then
               Throw New Exception("No analog video capture device available")
            End If

            capturectrl.VideoDevices("Analog").Selected = True

            Dim analogvideodecoder As AnalogVideoDecoder = capturectrl.AnalogVideoDecoder
            Dim availableFormats As AnalogVideoStandard = analogvideodecoder.AvailableTVFormats
            Dim tvFormat As AnalogVideoStandard = analogvideodecoder.TVFormat

            ' Check if format is NTSC and set it if not
                 If tvFormat <> AnalogVideoStandard.NTSC_M_J AndAlso (availableFormats And _
                                                                      AnalogVideoStandard.NTSC_M_J) = _
                                                                      AnalogVideoStandard.NTSC_M_J Then
                     ' set the analog video decoder TV format
                     analogvideodecoder.TVFormat = AnalogVideoStandard.NTSC_M_J

                     ' check the changed format
                     allResults = allResults And (analogvideodecoder.TVFormat = AnalogVideoStandard.NTSC_M_J)
                 End If

            ' Check if Horizontal Locked is enabled
            Dim vLocked As Boolean = capturectrl.AnalogVideoDecoder.HorizontalLocked

            ' Some video device's Analog Decoder implementations do not
            ' support the following properties, so we wrap these property 
            ' accesses with a special try block to catch possible exceptions
            Try
               ' Check if VCR Horizontal Sync locking is enabled and set if not
               Dim vcrLocked As Boolean = capturectrl.AnalogVideoDecoder.VCRHorizontalLocking
               If (Not vcrLocked) Then
                  ' set VCR horzontal sync locking
                  capturectrl.AnalogVideoDecoder.VCRHorizontalLocking = True

                  ' include this as one of our checks
                  allResults = allResults And capturectrl.AnalogVideoDecoder.VCRHorizontalLocking
               End If

               ' Check if output enabled is set and set if not
               Dim outputEnabled As Boolean = capturectrl.AnalogVideoDecoder.OutputEnable
               If (Not outputEnabled) Then
                  ' enable output
                  capturectrl.AnalogVideoDecoder.OutputEnable = True

                  ' include this as one of our checks
                  allResults = allResults And capturectrl.AnalogVideoDecoder.OutputEnable
               End If
            Catch cex As COMException
               ' if the device does not support the properties above
               ' skip it and dont fail
               If cex.ErrorCode <> CInt(ErrorCode.E_PROP_ID_UNSUPPORTED) AndAlso cex.ErrorCode <> CInt(ErrorCode.E_PROP_SET_UNSUPPORTED) Then
                  Throw cex
               End If
            End Try

            Dim tries As Integer = 0

            ' check scan line count a few times 
            ' initial frames may differ from format spec, until frame data 
            ' has propogated through the capture graph
            Do While lines <> 525 AndAlso tries < 10
               ' get the number of scan lines in the output format
               lines = capturectrl.AnalogVideoDecoder.NumberOfLines
               System.Diagnostics.Debug.WriteLine("TV Format: " & analogvideodecoder.TVFormat.ToString() & ", Scan Lines: " & lines.ToString())
               tries += 1
            Loop

            ' include the line count check
            allResults = allResults And (lines = 525 AndAlso tries < 10)
            System.Diagnostics.Debug.WriteLine("Tries: " & tries.ToString())

            ' test results
            _result = allResults
         Catch e1 As Exception
            _result = False
         End Try
      End Sub

Public NotInheritable Class LEAD_VARS
   Public Const MediaDir As String = "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 175\Media";
End Class
public bool _result = false;
      public CaptureCtrlForm _form = new CaptureCtrlForm();
      public void AvailableTVFormatsExample()
      {
         try
         {
            // reference the forms capture control
            CaptureCtrl capturectrl = _form.CaptureCtrl;

            string outFile = Path.Combine(LEAD_VARS.MediaDir, "AnalogVideoDecoder_AvailableTVFormatsExample.avi");
            int lines = 0;
            bool allResults = true;

            // select the first device with the word "analog" in its name
            // Replace "Analog" with the name of your tuner device
            if (capturectrl.VideoDevices["Analog"] == null)
               throw new Exception("No analog video capture device available");

            capturectrl.VideoDevices["Analog"].Selected = true;

            AnalogVideoDecoder analogvideodecoder = capturectrl.AnalogVideoDecoder;
            AnalogVideoStandard availableFormats = analogvideodecoder.AvailableTVFormats;
            AnalogVideoStandard tvFormat = analogvideodecoder.TVFormat;

            // check whether the format is NTSC and set it if not
            if (tvFormat != AnalogVideoStandard.NTSC_M_J
               && (availableFormats & AnalogVideoStandard.NTSC_M_J) == AnalogVideoStandard.NTSC_M_J)
            {
               // set the analog video decoder TV format
               analogvideodecoder.TVFormat = AnalogVideoStandard.NTSC_M_J;

               // check the changed format
               allResults &= (analogvideodecoder.TVFormat == AnalogVideoStandard.NTSC_M_J);
            }

            // check whether Horizontal Locked is enabled
            bool vLocked = capturectrl.AnalogVideoDecoder.HorizontalLocked;

            // Some video device's Analog Decoder implementations do not
            // support the following properties, so we wrap these property 
            // accesses with a special try block to catch possible exceptions
            try
            {
               // check whether VCR Horizontal Sync locking is enabled and set it if not
               bool vcrLocked = capturectrl.AnalogVideoDecoder.VCRHorizontalLocking;
               if (!vcrLocked)
               {
                  // set VCR horzontal sync locking
                  capturectrl.AnalogVideoDecoder.VCRHorizontalLocking = true;

                  // include this as one of our checks
                  allResults &= capturectrl.AnalogVideoDecoder.VCRHorizontalLocking;
               }

               // check whether output enabled is set and set it if not
               bool outputEnabled = capturectrl.AnalogVideoDecoder.OutputEnable;
               if (!outputEnabled)
               {
                  // enable output
                  capturectrl.AnalogVideoDecoder.OutputEnable = true;

                  // include this as one of our checks
                  allResults &= capturectrl.AnalogVideoDecoder.OutputEnable;
               }
            }
            catch (COMException cex)
            {
               // if the device does not support the properties above
               // skip it and do not fail
               if (cex.ErrorCode != (int)ErrorCode.E_PROP_ID_UNSUPPORTED
                  && cex.ErrorCode != (int)ErrorCode.E_PROP_SET_UNSUPPORTED)
                  throw cex;
            }

            int tries = 0;

            // check scan line count a few times 
            // initial frames may differ from format spec, until frame data 
            // has propogated through the capture graph
            while (lines != 525 && tries++ < 10)
            {
               // get the number of scan lines in the output format
               lines = capturectrl.AnalogVideoDecoder.NumberOfLines;
               System.Diagnostics.Debug.WriteLine("TV Format: " 
                                                  + analogvideodecoder.TVFormat.ToString() 
                                                  + ", Scan Lines: " 
                                                  + lines.ToString());
            }

            // include the line count check
            allResults &= (lines == 525 && tries < 10);
            System.Diagnostics.Debug.WriteLine("Tries: " + tries.ToString());

            // test results
            _result = allResults;
         }
         catch (Exception)
         {
            _result = false;
         }
      }

static class LEAD_VARS
{
   public const string MediaDir = @"C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 175\Media";
}
Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

See Also

Reference

AnalogVideoDecoder Class
AnalogVideoDecoder Members

 

 


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Leadtools.Multimedia requires a Multimedia or Multimedia Suite license and unlock key. For more information, refer to: LEADTOOLS Toolkit Features