Critic’s Pick:  ‘Begin Again’ mends any broken heart in sight

There are many reasons why “Begin Again” continues to have such great staying power against the big guns this summer. Expanding its run in L.A. this weekend, the story is a catchy one, the music is great, and it is flavored by real musicians, including Mos Def, CeeLo Green and a star turn by Maroon 5’s Adam Levine. Irish filmmaker John Carney, the writer-director whose indie sensation about a Dublin street busker, “Once,” became a Tony-winning show (now playing at the Pantages Theatre in Hollywood), is a lover of musicians and their flaws. Those passions seep into his work in mysterious and mesmerizing ways. “Begin Again” is New York street through and through, with a link to London via its undiscovered singer-songwriter Gretta (Keira Knightley), who’s come to the city with her soon-to-be-rock-star boyfriend, played by Levine. Perhaps because we’ve meet Knightley’s Gretta at a fragile moment in her life, love lost, all that, the actress shows a lovely softness we rarely see. Mark Ruffalo is perfectly bruised as the broken-down record producer in the midst of a bender when he discovers Gretta. The secret to the film’s success is the way it lets the music — and the making of it — mend any broken heart in sight.