Webcam and SMC problems Whenever I open up FaceTime/Photo Booth/Discord etc., they come up with an error that my (internal) webcam cannot detected. The way I fix this is to reset the SMC , which does work but only for a few minutes, and then we are back to square one.
I have tried sudo killall VDCAssistant and sudo killall VDCAssistant to no avail.
I am running macOS Mojave, 10.14.3 on a mid-2012 MacBook Air

Does anyone have any idea on how to fix this?
Try this: quit all apps attempting to use the camera, Finder -> Utilities -> Terminal (you'll likely be asked for your password, this is normal):

sudo killall VDCAssistant
sudo killall AppleCameraAssistant


…and reopen a camera app. I had an old MacBook Pro with a twitchy camera, and this solved it.