VideoCapture.open: Take a long time to open a USB camera.

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I use VideoCapture class to open a USB camera. Windows10, Visual Studio 2015, Opencv4.0.

VideoCapture cap; cap.open(0);

But the "cap.open(0)" line takes a long time to open my USB camera.

The output of VS is continously "Failed to create ID3D11DeviceContext", and after almost 1 min, it opened the camera successfully.

I have change to another camera, no error occurred. And the same camera on other computer, no error, too. So why this camera on this laptop got trouble? What should be the problem, on computer or camera? Thanks.