PreviousFrame Method

Imports Leadtools 
Imports Leadtools.MediaFoundation 
Imports LeadtoolsMediaFoundationExamples.Fixtures 
 
Public _result As Boolean = False 
Public _form As PlayCtrlForm = New PlayCtrlForm() 
Public _playctrl As PlayCtrl 
Public _seekingCaps As PlaySeeking 
Public _start As TimeSpan = TimeSpan.Zero 
 
Public Sub HasDialogExample() 
   ' reference the play control 
   _playctrl = _form.PlayCtrl 
 
   ' input file for playback 
   Dim inFile As String = Path.Combine(LEAD_VARS.MediaDir, "PlayCtrl_Source.avi") 
 
   Try 
      ' turn off autostart and auto rewind 
      _playctrl.AutoStart = False 
      _playctrl.AutoRewind = False 
 
      ' set the source file 
      _playctrl.SourceFile = inFile 
 
      ' show some media info if available 
      ShowMediaInfo() 
 
      ' the HasDialog method tells us that the control 
      ' can display the desired settings dialog. 
      ' check to see if the selected video processor properties dialog is available 
      If _playctrl.HasDialog(PlayDlg.SelVideoProcessor) Then 
         ' now show it to change some settings 
         _playctrl.ShowDialog(PlayDlg.SelVideoProcessor, _form) 
         _result = True 
      End If 
 
      ' get the source object type 
      Dim sot As SourceObjectType = _playctrl.SourceType 
 
      ' check some audio properties 
      Dim mute As Boolean = _playctrl.Mute 
      Dim bal As Integer = _playctrl.Balance 
      Dim vol As Integer = _playctrl.Volume 
 
      ' seeking caps - you can use these to enable menu states or toolbar buttons 
      _seekingCaps = _playctrl.CheckSeekingCapabilities(PlaySeeking.Forward Or PlaySeeking.Backward) 
 
      ' subscribe to the key press event to demo play functions 
      AddHandler _playctrl.KeyPress, AddressOf PlayCtrl_KeyPress 
 
      ' start the capture process 
      _playctrl.Run() 
 
      ' 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 _playctrl.State = PlayState.Running _ 
           OrElse _playctrl.State = PlayState.Paused _ 
           OrElse _playctrl.State = PlayState.NotReady 
         Application.DoEvents() 
      Loop 
 
      ' call reset source here to release resources 
      ' but not necessary if we are just exiting 
      _playctrl.ResetSource() 
   Catch e1 As Exception 
      _result = False 
   End Try 
End Sub 
 
' state variables for helper timer states 
Public _markedSelStart As Boolean = False 
Public _markedSelEnd As Boolean = False 
Public _seekedSelStart As Boolean = False 
Public _seekedSelEnd As Boolean = False 
 
' key press event handler to manage playback functions 
Private Sub PlayCtrl_KeyPress(ByVal sender As Object, ByVal e As Leadtools.MediaFoundation.KeyPressEventArgs) 
   Dim key As Char = CChar(ChrW(e.keyAscii)) 
   Select Case key 
      Case "b"c 
         If (Not _markedSelStart) Then 
            _markedSelStart = True 
            _playctrl.MarkSelectionStart() 
            System.Diagnostics.Debug.WriteLine("Mark Selection Start: " & _playctrl.SelectionStart.ToString() & " secs") 
            System.Diagnostics.Debug.WriteLine("  ... playctrl.State: " & _playctrl.State.ToString()) 
         End If 
      Case "e"c 
         If (Not _markedSelEnd) Then 
            _markedSelEnd = True 
            _playctrl.Pause() 
            _playctrl.MarkSelectionEnd() 
            System.Diagnostics.Debug.WriteLine("Mark Selection End: " & _playctrl.SelectionEnd.ToString() & " secs") 
            System.Diagnostics.Debug.WriteLine("  ... playctrl.State: " & _playctrl.State.ToString()) 
            _playctrl.SeekSelectionStart() 
            _playctrl.Run() 
         End If 
      Case "s"c 
         If (Not _seekedSelStart) Then 
            _seekedSelStart = True 
            System.Diagnostics.Debug.WriteLine("Seek To Selection Start: " & _playctrl.SelectionStart.ToString() & " secs") 
            System.Diagnostics.Debug.WriteLine("  ... playctrl.State: " & _playctrl.State.ToString()) 
            _playctrl.SeekSelectionStart() 
         End If 
      Case "f"c 
         ' toggle full screen 
         _playctrl.ToggleFullScreenMode() 
      Case "+"c 
         If _playctrl.State = PlayState.Running Then 
            _playctrl.Pause() 
         End If 
 
         _playctrl.NextFrame() 
      Case "-"c 
         If _playctrl.State = PlayState.Running Then 
            _playctrl.Pause() 
         End If 
 
         _playctrl.PreviousFrame() 
      Case "z"c 
         If (Not _seekedSelEnd) Then 
            ' turn off full screen mode 
            _playctrl.FullScreenMode = False 
 
            _seekedSelEnd = True 
            System.Diagnostics.Debug.WriteLine("Seek To Selection End: " & _playctrl.SelectionEnd.ToString() & " secs") 
            System.Diagnostics.Debug.WriteLine("  ... playctrl.State: " & _playctrl.State.ToString()) 
            _playctrl.SeekSelectionEnd() 
         End If 
      Case "x"c 
         _playctrl.Stop() 
 
   End Select 
End Sub 
 
Private Sub ShowMediaInfo() 
   Dim d As Double = 0 
   Dim sa, scr, sd, sr, st As String 
 
   sa = "Unavailable" 
   scr = "Unavailable" 
   sd = "Unavailable" 
   sr = "Unavailable" 
   st = "Unavailable" 
 
   Try 
      d = _playctrl.FrameDuration 
      sa = _playctrl.Author 
      scr = _playctrl.Copyright 
      sd = _playctrl.Description 
      sr = _playctrl.Rating 
      st = _playctrl.Title 
   Catch e1 As Exception 
   End Try 
 
   MessageBox.Show(_form, String.Format("Duration: {0}" _ 
                                        & Microsoft.VisualBasic.Constants.vbLf _ 
                                        & "Author: {1}" _ 
                                        & Microsoft.VisualBasic.Constants.vbLf _ 
                                        & "Copyright: {2}" _ 
                                        & Microsoft.VisualBasic.Constants.vbLf _ 
                                        & "Desc: {3}" & Microsoft.VisualBasic.Constants.vbLf _ 
                                        & "Rating: {4}" & Microsoft.VisualBasic.Constants.vbLf _ 
                                        & "Title: {5}" _ 
                                        & Microsoft.VisualBasic.Constants.vbLf, 
                                        d, sa, scr, sd, sr, st), "Media Info") 
End Sub 
 
Private Sub SelectedOptions() 
   _playctrl.SeekStart() 
   _playctrl.SeekEnd() 
   Dim te As Integer = _playctrl.TrackingSelectionEnd 
   Dim ts As Integer = _playctrl.TrackingSelectionStart 
   Dim se As Double = _playctrl.SelectionEnd 
   Dim ss As Double = _playctrl.SelectionStart 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const MediaDir As String = "C:\Program Files (x86)\LEAD Technologies\LEADTOOLS 20\Media" 
End Class