Chris Willman Senior Music Writer and Chief Music Critic When Mary McCartney was approached by producer John Battsek (“Searching for Sugar Man,” “One Day in September”) to make a film about the legendary Abbey Road Studios in London, she didn’t immediately leap at the chance, the way almost any other photographer interested in making the leap into documentary filmmaking might have. It’s not difficult to guess at the reason she might have balked at, and then succumbed to, the idea of making “If These Walls Could Sing,” which premiered at the Telluride Film Festival over the weekend and has been picked up for airing on Disney+. “I think because of my surname, I get a little bit oversensitive,” says the daughter of Paul McCartney, sitting at a sidewalk-adjacent table in Telluride. “I used to sort of shy away from anything to do with my family, wanting with my photography to be making a name for myself in my own area. I mean, I’ve always been really proud of my family, but then recently I’ve realized (I should) actually not shy away from it because I feel like I’m being judged. …. Before, I was like, my family’s my family and my career’s my career, and now I’m at the point where I’m confident enough to merge the two.”