https://doc.qt.io/qt-6/qtmultimedia-video-recorder-example.html 

The device selection combo boxes don't populate text. You can select the devices from the drop-down lists, however. (even though you don't know what you are selecting)

I can see the names of the devices after they are selected (though they are very hard to read as the text color is white, and the control bar is also white a partially transparent)

the combo boxes in the encoder settings do work