Problems getting a window capture with Bitblt and PrintWindow.

[VanGoghGaming]

Feel free to contribute with your code about image recognition.

If we are talking strictly about taking screenshots of videos then you could always do that with a simple "BitBlt" from the desktop window. This "WinRT Capture" approach has two main advantages over that:

1. It works while the video is playing in the background as long as its window is not minimized.
2. You can capture multiple frames at a time (I think the number of frames is capped at the refresh rate of your monitor, for example 60 frames per second).

You can modify the number of frames in the following line of code. Where it currently says "1", you can put any number of frames:

Invoke(pIDirect3D11CaptureFramePoolStatics, IDirect3D11CaptureFramePoolStatics_Create, ObjPtr(objIDirect3DDevice), _
DXGI_FORMAT_B8G8R8A8_UNORM, 1, m_lWidth, m_lHeight, VarPtr(pIDirect3D11CaptureFramePool))

Using this method you can actually stream the video in real time straight into a PictureBox. The following code streams 1 second of video (60 frames) into the PictureBox from the main form. It's as fluid as the actual video player:

Private Function StartCapture(ByVal pIGraphicsCaptureItem As Long) As Boolean
    Dim pIDirect3D11CaptureFramePool As Long, lFrames As Long
    lFrames = 60
    If Invoke(pIDirect3D11CaptureFramePoolStatics, IDirect3D11CaptureFramePoolStatics_Create, ObjPtr(objIDirect3DDevice), DXGI_FORMAT_B8G8R8A8_UNORM, lFrames, m_lWidth, m_lHeight, VarPtr(pIDirect3D11CaptureFramePool)) = S_OK Then
        Dim pIGraphicsCaptureSession As Long
        If Invoke(pIDirect3D11CaptureFramePool, IDirect3D11CaptureFramePool_CreateCaptureSession, pIGraphicsCaptureItem, VarPtr(pIGraphicsCaptureSession)) = S_OK Then
            Dim pIGraphicsCaptureSession2 As Long
            If Invoke(pIGraphicsCaptureSession, IUnknown_QueryInterface, pIID_IGraphicsCaptureSession_2, VarPtr(pIGraphicsCaptureSession2)) = S_OK Then
                Call Invoke(pIGraphicsCaptureSession2, IGraphicsCaptureSession2_PutIsCursorCaptureEnabled, 0&)
                Call Release(pIGraphicsCaptureSession2)
            End If
            Dim pIGraphicsCaptureSession3 As Long
            If Invoke(pIGraphicsCaptureSession, IUnknown_QueryInterface, pIID_IGraphicsCaptureSession_3, VarPtr(pIGraphicsCaptureSession3)) = S_OK Then
                Call Invoke(pIGraphicsCaptureSession3, IGraphicsCaptureSession3_PutIsBorderRequired, 0&)
                Call Release(pIGraphicsCaptureSession3)
            End If
            If Invoke(pIGraphicsCaptureSession, IGraphicsCaptureSession_StartCapture) = S_OK Then
                Dim pIDirect3D11CaptureFrame As Long, i As Long
                For i = 0 To lFrames - 1
                    While pIDirect3D11CaptureFrame = 0: Call Invoke(pIDirect3D11CaptureFramePool, IDirect3D11CaptureFramePool_TryGetNextFrame, VarPtr(pIDirect3D11CaptureFrame)): Wend
                    Dim pIDirect3DSurface As Long
                    If Invoke(pIDirect3D11CaptureFrame, IDirect3D11CaptureFrame_GetSurface, VarPtr(pIDirect3DSurface)) = S_OK Then
                        StartCapture = GetImageFromIDirect3DSurface(pIDirect3DSurface)
                        Call CloseAndRelease(pIDirect3DSurface)
                    End If
                    Call CloseAndRelease(pIDirect3D11CaptureFrame)
                    Set frmMain.picCapture.Picture = Picture
                Next i
            End If
            Call CloseAndRelease(pIGraphicsCaptureSession)
        End If
        Call CloseAndRelease(pIDirect3D11CaptureFramePool)
    End If
End Function