As trade for rescue and partial rehabilitation, a brilliantly talented but extremely disadvantaged person of color changes a white man’s life. And the white man is played by a guy who did a movie in blackface last year. And this movie might not have worked without him. Wow. Writer Susannah Grant and director Joe Wright adapt the memoir by Los Angeles Times columnist Steve Lopez (Robert Downey Jr.) about discovering schizophrenic cello prodigy Nathaniel Anthony Ayers (Jamie Foxx) living on the city’s streets. Foxx’s sometimes contrived performance is compelling enough, but the movie belongs to Downey, whose sharply antisentimental charisma is its most dramatically definitive feature and saving grace. He nails the vainglorious whining about responsibility to his editor and ex (Catherine Keener), and plays the obligatory voice-over narration with just enough calculation and detachment, as if everything Lopez says—and feels and thinks—is an early draft of his column being sounded out. It mitigates Wright’s perfunctory attempts, via color-field abstractions, to get inside Ayers’ beautiful broken mind; This is a filmmaker who, in Atonement, improbably restaged the entire Allied evacuation of Dunkirk, but where the ephemeral beauties of Beethoven’s Third symphony are concerned, the best he can offer is basically an iTunes screensaver? J.K.