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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.xojo_binary_project"
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
FileTypes1
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
See also:
The items on this page are in the following plugins: MBS Win Plugin.