Tim Burton turned his “Corpse Bride” into a cheerily macabre argument for stop-motion animation, and when the pic’s DVD extras stick to the tireless work of the animators, they can be just as entertaining. The best of seven brief docus — none more than nine minutes — study the arduous process of getting a stop-motion film made. Watching animators painstakingly move a puppet’s eyelids into a new expression is tantamount to DVD Zen. Welcome insight also comes from co-director Mike Johnson, who gently scoffs at the notion that CGI will become the only animation game in town. Unfortunately, docus focusing on the project’s bigger names — Burton, voiceover star Johnny Depp — are never so informative.