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/Win/DirectShow/PlayCap with frame grabber event
Required plugins for this example: MBS Win Plugin
You find this example project in your Plugins Download as a Xojo project file within the examples folder: /Win/DirectShow/PlayCap with frame grabber event
This example is the version from Tue, 3rd Sep 2012.
Project "PlayCap with frame grabber event.rbp"
Class App Inherits Application
Const kEditClear = "&Löschen"
Const kFileQuit = "Beenden"
Const kFileQuitShortcut = ""
EventHandler Sub Open() if TargetWin32 then // ok else MsgBox "This example requires Windows." quit end if End EventHandler
End Class
Class Window1 Inherits Window
Control Canvas1 Inherits Canvas
ControlInstance Canvas1 Inherits Canvas
End Control
Control BevelButton1 Inherits BevelButton
ControlInstance BevelButton1 Inherits BevelButton
EventHandler Sub Action() dim p as Picture = grabber.Current if p = nil then System.DebugLog "No picture? "+str(grabber.Lasterror) else dim w as new window2 w.Backdrop = P W.SHOW end if End EventHandler
End Control
Control frames Inherits Label
ControlInstance frames Inherits Label
End Control
EventHandler Sub Close() CloseInterfaces End EventHandler
EventHandler Sub Maximize() if mc<>Nil then mc.run end if End EventHandler
EventHandler Sub Minimize() if mc<>Nil then mc.StopWhenReady end if End EventHandler
EventHandler Sub Open() if TargetWin32 then CaptureVideo end if End EventHandler
EventHandler Sub Resized() ResizeVideoWindow End EventHandler
EventHandler Sub Resizing() ResizeVideoWindow End EventHandler
Sub CaptureVideo() // Get DirectShow interfaces GetInterfaces // Attach the filter graph to the capture graph Capture.SetFiltergraph(graph) // Use the system device enumerator and class enumerator to find // a video capture/preview device, such as a desktop USB video camera. srcfilter = FindCaptureDevice grabber = new MyDirectShowSampleGrabberMBS grabberFilter = grabber.BaseFilter // Add Capture filter to our graph. Graph.AddFilter srcfilter, "Video Capture" Graph.AddFilter grabberFilter, "Grabber" // Render the preview pin on the video capture filter Capture.RenderStream(DirectShowPinMBS.PIN_CATEGORY_PREVIEW, Capture.MEDIATYPE_Video, srcfilter, grabberFilter) // Set video window style and position SetupVideoWindow // Start previewing video data mc.Run if mc.Lasterror = 1 then // not yet ready, try again mc.Run end if End Sub
Sub CloseInterfaces() // Stop previewing data if mc<>Nil then mc.StopWhenReady end if // Stop receiving events if mee<>nil then 'mee.SetNotifyWindow( end if // Relinquish ownership (IMPORTANT!) of the video window. // Failing to call Owner setter can lead to assert failures within // the video renderer, as it still assumes that it has a valid // parent window. if vw<>nil then vw.Visible = false vw.Owner = nil end if // Release DirectShow interfaces mc = nil mee = nil vw = nil Graph = nil Capture = nil End Sub
Function FindCaptureDevice() As DirectShowBaseFilterMBS // Create an enumerator for the video capture devices dim devenum as new DirectShowEnumMonikerMBS(DirectShowEnumMonikerMBS.CLSID_VideoInputDeviceCategory) if devenum.Handle = 0 then MsgBox "No video capture device found." end if dim dev as DirectShowMonikerMBS = devenum.NextObject if dev<>nil then // Bind Moniker to a filter object dim f as DirectShowBaseFilterMBS = dev.BindBaseFilter Return f end if End Function
Sub GetInterfaces() // Create the filter graph graph = new DirectShowGraphBuilderMBS // Create the capture graph builder capture = new DirectShowCaptureGraphBuilderMBS // Obtain interfaces for media control and Video Window MC = Graph.MediaControl VW = Graph.VideoWindow MEE = Graph.MediaEventEx End Sub
Sub ResizeVideoWindow() if vw<>Nil then // Resize the video preview window to match owner window size vw.SetWindowPosition canvas1.Left, canvas1.top, canvas1.Width, canvas1.Height end if End Sub
Sub SetupVideoWindow() // Set the video window to be a child of the main window vw.Owner = self // Set video window style vw.WindowStyle = BitwiseOr(vw.WS_CHILD, vw.WS_CLIPCHILDREN) // Use helper function to position video window in client rect // of main application window ResizeVideoWindow // Make the video window visible, now that it is properly positioned vw.Visible = true End Sub
Property Capture As DirectShowCaptureGraphBuilderMBS
Property Graph As DirectShowGraphBuilderMBS
Property MC As DirectShowMediaControlMBS
Property MEE As DirectShowMediaEventExMBS
Property VW As DirectShowVideoWindowMBS
Property grabber As MyDirectShowSampleGrabberMBS
Property grabberFilter As DirectShowBaseFilterMBS
Property srcfilter As DirectShowBaseFilterMBS
End Class
MenuBar MenuBar1
MenuItem FileMenu = "File"
MenuItem FileQuit = "#App.kFileQuit"
MenuItem EditMenu = "Edit"
MenuItem EditUndo = "&Rückgängig"
MenuItem UntitledMenu1 = "-"
MenuItem EditCut = "&Ausschneiden"
MenuItem EditCopy = "&Kopieren"
MenuItem EditPaste = "&Einfügen"
MenuItem EditClear = "#App.kEditClear"
MenuItem UntitledMenu0 = "-"
MenuItem EditSelectAll = "&Alles auswählen"
End MenuBar
Filetype video/avi
End FileTypes1
Class Window2 Inherits Window
End Class
Class MyDirectShowSampleGrabberMBS Inherits DirectShowSampleGrabberMBS
EventHandler Sub NewFrame(Time as double) count = count + 1 window1.Frames.text = str(count) End EventHandler
Property count As Integer
End Class
End Project

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