Creating a live mask using color thresholding

Right. What I’m trying to achieve is to create a live mask from an RGB video input(HDMI output from a camera) to seperate background and subjects. keep the subjects and key out the background, yes.

So for the purpose like this, it could be done easily if I switch the backdrop to green but I’m not sure if I’m able to get the same cinematic feeling with that. I know chroma keying is common in film making but I want to do it on live situation so it must have limitations of resources,

I’ve already installed a backlight right behind the subject to get the outline, something like a halo thing around the subject. But what you linked is much more advanced than my setting. Thank you for this!