I installed Ubuntu 18.04 LTS as a guest on OSX VirtualBox, and enabled the builtin webcam on Macbook.
While I thought the webcam wasn't working because sudo cheese
command wasn't picking up anything except for assertion fail: device != NULL
log, trying something with VLC(vlc v4l2:///dev/video0
) properly picked up webcam and worked.
I want to know why VLC works but Cheese doesn't, but can't figure out what to look for. I looked up this SO post insisting that cheese has some issues, but that post didn't make clear what issues that can cause Cheese not to pick up stream properly .