It’s grand that a physical, mindful force of 1960s American alternative cinema like Melvin Van Peebles can tell a story at the age of 75 about being an anti-Hollywood “maverick” with an epochal success like 1971’s “Sweet Sweetback’s Badassss Song.” With “Confessions of A Ex-Doofus-Itchy Footed Mutha,” the grand old man and inveterate trickster figure becomes an unregenerate youth forever on the run. Based on his 1982 Broadway production, “Waltz of the Stork,” this partly musical semi-autobiographical fantasia uses the lower rungs of digital-video imagery to compile Van Peeble’s imagination from boyhood to middle age to mixed result. “Ex-Doofus-Itchy” is a mass of hardly digested material about twentieth-century African-American cultural experience that rings both true and deadly. Peebles looks tired. He’s lived a life. Then he made this movie. 75m. DigiBeta video. (Ray Pride)