Recently I've noticed a green dot next to my webcam staying on beyond my Google Hangout/Zoom meetings. This is obviously a problem so I've set out to find the solution.
Ends up it is pretty simple. All you need is lsof and grep.
To find out if your built-in webcam is being used:
lsof | grep Camera
Although that doesn't catch all the cases. Some apps use something called VDC to access the webcam.
lsof | grep VDC
For me the VDC command was the on that finally worked. Example Output:
~/ » lsof | grep VDC 1 ↵ tbrazelton@drpepper
Google 343 tbrazelton txt REG 1,5 424176 1152921500312556127 /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC
Slack 355 tbrazelton txt REG 1,5 424176 1152921500312556127 /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC
FaceTime 13975 tbrazelton txt REG 1,5 424176 1152921500312556127 /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC
avconfere 13977 tbrazelton txt REG 1,5 424176 1152921500312556127 /System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/MacOS/VDC
When I shut off FaceTime the green light went away and so did my sticky note.