def get_cv2_backend() in camera.utils

[Emonumia]

The default backend for Windows is set to CAP_AVFOUNDATION.

Which is not the right backend for Windows and thus does not work.

Use CAP_DSHOW instead, and it will work on Windows.

[sdesrozis]

Same issue on Windows, and yes, it seems that the default backend is not correct.
I've proposed a very simple fix.
HTH

[todateman]

I have submitted a pull request to fix this so that the backend can be switched correctly depending on the OS.

#1495