“I have an inner voice or ego, whatever we want to call it, who’s a tyrant, a dictator, who’s never happy with what I do,” says director Alejandro González Iñárritu. In the director and co-writer’s audaciously executed, mindbending dark comedy, “Birdman (or the Unexpected Virtue of Ignorance),” that cruel inner voice springs from its subject’s greatest success. Stop me if you’ve heard this one, but Michael Keaton plays an actor who reached the apex of fame playing a caped-and-cowled superhero decades ago. Complicating Riggan’s attempt at ascension are a vicious critic (Lindsay Duncan), a loose-cannon actor (Edward Norton), a daughter fresh out of rehab (Emma Stone), and his own tenuous grip on reality. [...] a Buddhist might say Riggan longs to transcend, but earthly attachments weigh him down. The film’s central cinematic conceit of a single, unbroken take is plenty to digest, but “Birdman” still manages a little mustard on the side: a few shots at the press, a few actor digs and in-jokes — biting, but with fondness. The film’s cast, particularly the sympathetic Keaton, is getting awards buzz. The decisions one has to make when you will not have coverage, the wide shot, the close-up, the over-the-shoulder, all those things you would play with to find the tone, the internal rhythm of the film; to know where to put the camera in every moment, which point of view you should be serving … and freaking out about the transitions. Oscar-winning cinematographer Emmanuel Lubezki “obviously did an amazing job — everything is practical light,” Iñárritu says. The focus puller, the camera operator, the boom-sound, with those corridors and the beat (by jazz drummer Antonio Sánchez) and the opening doors and the rhythm, every actor’s line and specific marks.