[PD] GEM camera input unavailable?

[Dana Moser]

Greetings.
I teach in a program that uses both Linux and
Mac laptops. About a year ago video input stopped
working ('High Sierra' version or before, apparently.)
I'm told it's no longer working on Windows either.
My colleague has suggested it's because enhanced
security in the OS is guarded about which devices
can access a given piece of software and Pd/GEM isn't
asking for permission correctly, so a camera never shows
up as an input device. Is this possible?
We're using Pd 0.49.4 and Gem 0.93.3.
Is there a known method of getting a live video camera
input for the Mac? It works fine on Linux.
Thank you for any assistance.
-Dana Moser