Part wartime drama, part historical mystery, Wajda’s sprawling dramatization of the infamous “Katyn” massacre spans the years 1939 to 1945, spinning out a number of storylines and characters (a survivor who testifies that the Germans were responsible; two sisters on opposite sides of the postwar regime) to delineate the experiences of those who lived through it. Wajda lost his own father at Katyn at age 14, so there’s a personal dimension to his storytelling, since Anna and Andrzej are essentially stand-ins for his parents. But Wajda (“Ashes and Diamonds”) is as concerned with epic structuring and stylized imagery as he is with themes of truth and responsibility, and “Katyn” is a master study in fluid editing and filmmaking brio.