I'm capturing the screens using desktop duplication APIs (DirectX11). The DuplicateOutput API returns the access denied error and that too happens very rare(may be 10% of the time) on a windows 8.1 machine on logon screen though my application is running with SYSTEM level privileges and the SetThreadDesktop being called properly. I used to reset and call SetThreadDesktop after every error I got but the application couldn't recover from the error after that even after multiple device resets and inits. I had to fallback to GDI (application works fine after being switched from directx to GDI) based approach after multiple retries or restart the application but that idea seems terrible.
Note: I did come across the same problem on Windows 10/ Windows 8 machines but not too often compared to that particular windows 8.1 machine.
here is the description of the E_ACCESSDENIED error that tells only possible case (not having system level privileges or the SetThreadDesktop not being called properly) for this error. I tried all the possible ways to find out the problem but couldn't.
Any help would be appreciated, Thanks in advance.
Here is the code to init the device:
//
// Initialize duplication interfaces
//
HRESULT cDuplicationManager::InitDupl(_In_ ID3D11Device* Device, _In_ IDXGIAdapter *_pAdapter, _In_ IDXGIOutput *_pOutput, _In_ UINT Output)
{
HRESULT hr = E_FAIL;
if(!_pOutput || !_pAdapter || !Device)
{
return hr;
}
m_OutputNumber = Output;
// Take a reference on the device
m_Device = Device;
m_Device->AddRef();
_pOutput->GetDesc(&m_OutputDesc);
// QI for Output 1
IDXGIOutput1* DxgiOutput1 = nullptr;
hr = _pOutput->QueryInterface(__uuidof(DxgiOutput1), reinterpret_cast<void**>(&DxgiOutput1));
if (FAILED(hr))
{
return ProcessFailure(nullptr, _T("Failed to QI for DxgiOutput1 in DUPLICATIONMANAGER"), _T("Error"), hr);
}
// Create desktop duplication
hr = DxgiOutput1->DuplicateOutput(m_Device, &m_DeskDupl);
DxgiOutput1->Release();
DxgiOutput1 = nullptr;
if (FAILED(hr) || !m_DeskDupl)
{
if (hr == DXGI_ERROR_NOT_CURRENTLY_AVAILABLE)
{
return ProcessFailure(nullptr, _T("Maximum number of applications using Desktop Duplication API"), _T("Error"), hr);
}
return ProcessFailure(m_Device, _T("Failed to get duplicate output in DUPLICATIONMANAGER"), _T("Error"), hr);//, CreateDuplicationExpectedErrors);
}
return S_OK;
}
The code to set the desktop to current thread:
DWORD setCurrentInputDesktop()
{
DWORD errorCode = ERROR_ACCESS_DENIED;
HDESK currentInputDesktop = OpenInputDesktop(0, false, GENERIC_ALL);
if(currentInputDesktop != NULL)
{
if(!SetThreadDesktop(currentInputDesktop))
{
errorCode = GetLastError();
cout << ("setCurrentInputDesktop: SetThreadDesktop failed. Error code: ") << errorCode;
}
else
{
errorCode = ERROR_SUCCESS;
cout << ("setCurrentInputDesktop: SetThreadDesktop succeeded.");
}
CloseDesktop(currentInputDesktop);
}
else
{
errorCode = GetLastError();
cout << "setCurrentInputDesktop: OpenInputDesktop failed. Error code: " << errorCode;
}
return errorCode;
}
Here is the error message returned after processing the error code:
Id3d11DuplicationManager::ProcessFailure - Error: Failed to get duplicate output in DUPLICATIONMANAGER, Detail: Access is denied.