As they watch what's likely to stand as the strangest DVD special edition of the young year, All About Eve enthusiasts can choose from two feature-length commentary tracks. One, chattery with scene-specific gossip, is by Sam Staggs, author of the making-of history ''All About 'All About Eve.''' The other is shared by Kenneth Geist, author of a biography of the film's writer-director Joseph L. Mankiewicz, who announces right off the bat how much he disliked Staggs' book, then proceeds to grind his own axes with relentless tedium, and by Mankiewicz' son Christopher, who wastes not a moment in telling you that he doesn't think his ''cold'' father was a very interesting director and that he prefers Howard Hawks. (It will not surprise you to hear that Christopher was a fan of the book ''Mommie Dearest.'') Buried beneath what adds up to more than four hours of yammering is, incidentally, a pristine print of what is, line for quotable line, quite simply the best-written Hollywood movie ever. Plug your ears to the extras, and enjoy every poisonously funny word of a flat-out masterpiece.