Brazil is a bounty for documentarians and filmmakers who work in a documentary style, from “Pixote” to “Bus 174,” “City of God” to “Favela Rising.” It seems as though every five minutes there’s a new saga, drawn from the nation’s ragged and sprawling social underbelly, that illustrates the squalor and desperation of its poor, usually offset by the earthy vibrancy of the hillside favelas and scenes of the non-stop party on the nearly nude beaches.