Unlike virtually any theater-to-tape transfer before it, Stephen Sondheim's intimate 1994 musical actually blossoms in its filmed incarnation. Based on an 1869 Italian novel, Passion follows an unlikely love triangle between the beautiful Clara (an incandescent Marin Mazzie), her handsome lover Giorgio (Jere Shea), and the homely Fosca (Donna Murphy), who yearns for Giorgio with every bone in her sickly body. Multiple cameras capture Mazzie's sumptuous costumes, Shea's steely glances, and Murphy's tear-stained confessions. But the biggest bonus is the DVD's commentary -- in which the stars, Sondheim, collaborator Ira Weitzman, and director James Lapine look back on misunderstood moments, Murphy's now-renowned mole, orchestral orgasms, and how the lovers ''were screwing'' in a London production. Turns out the notoriously discriminating Sondheim is quite the chatterbox.