The Coens' latest film is a masterfully crafted melancholic comedy based in part on The Mayor of MacDougal Street, the posthumously published memoir of Greenwich Village singer Dave Van Ronk. They talk about compromise, casting and the difficulties of working with cats.

Dazed Digital: One of your starting points was an idea you had about a folkie getting beaten up outside a club...

Joel Coen: I guess it was years before we actually did anything with it. 
It just kept amusing us or intriguing us. Maybe it was a bad joke or something but we did remember it and at some point we thought, ‘What would be the story that would follow from that?' Sometimes things just get a little traction and they lead to a bigger conversation.

DD: You're working with T-Bone Burnett again on the music.

Joel Coen: Yeah, T-Bone is a mercurial genius. He's really funny, just one of those people you meet and go, ‘Let's do this again.' When we do movies with him with live music on the set, it brings a whole other element to the making of the movie that you don't usually get. It's really fun and you meet lots of interesting people who aren't like the usual collaborators on a movie. Most times it's the same designers and you work with them over and over again, but not musicians, unless you invite them in for a particular project.

DD: Was it important to have the music not only played live but songs played at full length in the film?

Ethan Coen: Inasmuch as the main character is a musician, yes. You wanted to see him perform. You wanted to see him do whole songs, do what he does for a living. So then we were faced with the fact of having to a find an actor that could actually do that live on set.

DD: How did you find Oscar Isaac?

Joel Coen: He came in and did an audition and it was lightning striking. The usual problems of finding the right person and casting were compounded a thousandfold in this case because of the particular requirements of the part. Oscar was a very, very accomplished musician but it's not like he was playing folk music his whole life or playing guitar the way Dave Van Ronk played guitar, for instance. So that's another way that T-Bone was this huge part of the movie, because he was coaching.

DD: Do you ever have actors in mind when you're writing?

Joel Coen: We often think about specific actors when we write and sometimes we write parts for them. Sometimes we write parts not knowing who's going to play them, and often in those cases we want to see someone do something totally out of leftfield.

Ethan Coen: Like, it's fun to see Carey swear like a stevedore.

“Maybe Llewyn Davis doesn't compromise because nobody's offering him enough money. It's similar to our situation" – Ethan Coen

DD: Where did you find the film's real star, the ginger tomcat?

Ethan Coen: There were several cats. As the animal trainer said to us, a dog wants to please you; a cat only wants to please itself. So that's a problem in terms of getting it to do a specific thing. Basically you can't, so there were several cats that had different attributes. You then just shoot a lot of film, because 99.7 per cent of it is the cat doing what you don't want it to be doing.

DD: Llewyn Davis won't compromise. Do you admire that about him, because you work in a way that appears to mean you haven't had to compromise?

Ethan Coen: I don't know if it's a heroic thing on his part. Maybe he doesn't compromise because he's a contrary, difficult person as opposed to an artistically principled person. And maybe if somebody offered him enough money he would compromise, but nobody's offering him enough money. Which, actually, is similar to our situation. (laughs)