It's like GDI->CPU+RAM, DirectX->GPU+VRAM that's why in screen capturing VLC's video playing part appears in black. While screen capturing (not from mobile or external camera) most of the capture mechanism captures screen by requesting GDI for screens, but hardware overlays are directly rendered on GPU and GDI can't access GPU. I would like to add this as the answer because lots of discussions is carried out in comments which are moved to chat, so I would like to summarize it so that upcoming viewers will get the idea about the discussion and the solution I ended up with.įirst I would like to clear the thing how VLC's "DirectX (DirectDraw) video output" works? VLC's this particular output mode uses DirectDraw for creating hardware overlay and video is played on it.
To make window transparent I used DwmExtendFrameIntoClientArea winapi, but now on remote also it's visible as transparent. Now, I am trying to set transparency to that window so that, overlay will on top of my C# application and candidate can give the exam and if remote is taken then overlay will get shown in black. So I created vc++ project and used d3d9 and created overlay with red color surface, now if I take remote of machine then the form with red color shows black in color.
#Ammyy admin 4.0 code
If you tried VLC player's "DirectX (DirectDraw) video output" then this output method also does the same thing like SetWindowDisplayAffinity, it puts black layer on video when any desktop sharing app is started and I tested this works with almost 9 desktop sharing apps, any idea how it's done? and can it be done with c# winform?Īfter checking VLC code I come to know that they are using hardware overlay using DirectDraw.
#Ammyy admin 4.0 full
This approache I coded is not full proof with all desktop sharing applications, so is there any 100% solution to prevent/detect desktop sharing? Result = SetWindowDisplayAffinity(winForm.Handle, WDA_NONE)
Result = SetWindowDisplayAffinity(winForm.Handle, WDA_MONITOR) How some applications shows black layer and some does not? Is there anything I can do additionally? Like TeamViewer behaves as expected but Ammyy Admin, AnyDesk does not. But not all desktop sharing application have the same behavior. By doing this when ever I start desktop sharing, the computer who has taken remote can see black layer over the form. As our application will run on windows 7 and above so I took advantage of DWM (Destop Window Manager) by checking desktop composition I set SetWindowDisplayAffinity to WDA_MONITOR to enable protection to my winform.To do This I have tried following thing so far: So I started exploring for preventing my c# winform getting displayed when desktop sharing is started. I don't think detection is that easy as their are so many ways to capture the screen Desktop Duplication API, BitBlt, Direct3D, DirectX, DirectShow and so many.
#Ammyy admin 4.0 software
Our examination software is developed in C#, it's a winform renders question one by one. While developing an examination software I have a requirement to prevent desktop sharing through applications like TeamViewer, AnyDesk, Ammyy Admin etc or at least detection of it.
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