calculating the square 'footage' of the room [=calculating the size of the room in square feet]
Some disturbing 'footage' of the war was shown on the evening news.
(..) Elena. My name's Elena. l wanted to tell you, well, the other day at the station-- The small projector? Your footage? What do you see? Slaughterhouse workers killing a heifer. Blood all over the floor, like a lake. (..)1988 Cinema Paradiso