Here is Steve Martin in a 1974 video he made at Ed's Warehouse restaurant and Markham Street in Toronto. Martin had done some late night talk show appearances, but this was still two years from his first SNL appearances, and three years from his 1977 debut album Let's Get Small, that propelled him to stardom.
It seems to me that Martin hadn't yet fully committed to the surrealist meta-irony that would shortly turn the corner on his comedy career, even though according to his autobiography Born Standing Up: A Comic's Life, he'd been experimenting with it for years. Or maybe he had honed that persona in his standup act, but was unable to translate it to video comedy.
I'm not sure why this video was made. But Ed's Warehouse was a restaurant opened up by Toronto businessman Ed Mirvish so that patrons of the nearby theater he had purchased, the Royal Alexandra Theatre, would have a place to eat before shows. As Martin alludes to in the video, Mirvish also bought other nearby properties, and rejuvinated the formerly derelict neighborhood. The YouTube video was posted in 2021 by "Mirvish Productions," so it seems likely he had done the video as a promotion for the restaurant.
Another video, viewable on Instagram, featuring Martin in 1974 Toronto playing banjo to an amused but somewhat confused street crowd, must have been made on the same trip to Toronto.