The teaser trailer for one of fall’s more interesting films — Alejandro Iñárritu’s Birdman, starring Michael Keaton as an actor famous for once portraying an iconic superhero but now going through an existential crisis — reveals it to be a jazzy, audacious, gleefully deranged slice of high-art cinema, and seemingly certainly a lot more loose-limbed than Biutiful, Babel, 21 Grams or Amores Perros. Opening to a downbeat version of Gnarls Barkley’s “Crazy,” this looks like a case study in slipping-knot sanity entertainingly rendered. Great subtitle on its poster, too: “The Unexpected Virtue of Ignorance.” Amy Ryan, Edward Norton, Naomi Watts, Emma Stone, Andrea Riseborough and Zach Galifianakis co-star. The film releases October 17 via Fox Searchlight.