For much of the 1970s, the legendary director Sergei Parajanov (1924–90) was imprisoned as a punishment for the crime of making mind-blowing movies. That’s the impression you get, at any rate, after experiencing “Shadows of Forgotten Ancestors,” the filmmaker’s 1964 breakthrough, which begins a week-long run today at the BAMcinématek, at the Brooklyn Academy of Music. This folk fever dream, seemingly possessed by pagan magic and infused with nonstop native music, roils with the all-consuming passion of its story about a shepherd, Ivan (Ivan Mikolajchuk), whose beloved Marichka (Larisa Kadochnikova) dies.