The film began as a mirror of his memoir, 2015’s “Can I Say: Living Large, Cheating Death, and Drums, Drums, Drums,” but became something else entirely after a producer suggested it end with the image of Barker, then still unable to fly due to post-traumatic stress disorder, walking toward a plane. The film hits most of the big notes, quickly establishing Barker as a rebellious kid with a supernatural drumming ability from age 4, when he got his first kit, to now, at 50. Even before the crash, Barker’s life — as marked with musical triumphs as it has been — offered lessons in resiliency.