Retrieving videoDevices blocks main event loop

Attached a small QML camera example which creates a Camera Item and iterates over all videoDevices to search for a specific one. The code searching for a USB camera but that part is not important.

When starting the example with the default backend on windows (ffmpeg) you can see that the main eventloop is blocked for >1 seconds to retrieve the available videoDevices.

Starting the same application with the "windows" backend reduces the blocking to a few milliseconds.