Let’s just say that with all due respect to Dreamgirls and Rent and other recent hand-me-downs from the Broadway-bathos school of moviemaking, it’s about time a motion-picture musical with authentic indie-rock aesthetics came along. What writer-director John Carney’s Sundance audience-award winner lacks in dramatization, it makes up for in raffish naturalism, a kind of lo-fi, lovelorn charm. Two young and heartsick aspiring musicians (Frames front man Glen Hansard, playing his own songs, and Czech singer-songwriter Markéta Irglová) meet on Dublin’s streets and begin an exquisite creative courtship, all full of doubts and hesitations and poignant mutual longings. Carney’s breezy storytelling treats the material generously, making intimacy a priority and taking every opportunity to meet vulnerability with kindness. It becomes a delight to discover that melodic, heartbreaking alt-pop really can be some people’s vernacular. The movie follows the music’s example beautifully, avoiding false notes altogether.