Stream from usb camera/hdmi

Hi,

I want to make an app that simply streams the input from an external usb camera (or in my case a hdmi which i have plugged into a hdmi-usbc converter).
No need for bells and whistles such as taking pictures or videos, I just need to see the live-stream.
Is this possible?
I've had a search on the forums but everything I came across was for complex projects involving arduino, raspberry pi etc whereas I don't need that level of complexity.

Thanks a lot!

Tom