I’m playing around with using DSLR cameras as webcams with gphoto (CLI to cameras over USB) and v4l2loopback (dummy video devices), which works with OBS but neither Skype nor VLC which will either show a black image or fail with an error message. Running VLC in verbose mode and digging a bit around showed that it’s a permission problem with Ubuntu and snap. The solution:
snap connect vlc:camera :camera
Resources
[1] Ask Ubuntu – webcam streaming problem
https://askubuntu.com/questions/1224092/ubuntu-18-04-webcam-streaming-problem
George's Techblog 