(PARK CITY, UT) -- ``Boys, there's only one thing in life you can count on, your own flesh and blood,'' old man Mitchell instructs his sons Jim and Artie, and ``Rated X'' bears out the homily's bitter irony as it applied to the lives of the infamous San Francisco pornmeisters of the '60s and '70s.

The inspired casting of brothers Emilio Estevez and Charlie Sheen as the creators of the hard-core landmark ``Behind the Green Door'' goes a long way toward keeping this biopic interesting, but the drug-fueled downward spiral that led to fratricide takes a long time to hit bottom and makes for pretty grim going. Sensational subject matter ensures beaucoup de publicity and viewership for this Showtime presentation once it hits cable, but this artistic poor cousin to ``Boogie Nights'' looks to have limited theatrical prospects.

The often ornery and belligerent Mitchell brothers were porno pioneers who lucked into fame and fortune when their beauteous discovery, Marilyn Chambers, was revealed to have been the ``99 and 44/100 percent pure'' model for Ivory Snow, which instantly turned ``Behind the Green Door,'' in which she starred, into one of the two or three biggest-grossing adult films of the hard-core theatrical era. Their well-known home-base O'Farrell Theater was the exhibition component of their attempt at a mini-empire and to ``keep it in the family, like the Warner Brothers.''

The Mitchells were probably busted and dragged into court more often than almost any other porn filmmakers, and their efforts to use the First Amendment to protect their business attracted considerable attention at the time. They were also, however, prime examples of the era's excesses, squandering their money, families and business discipline on drugs and generally dissolute lifestyles; no film since ``Scarface'' has featured such incessant snorting of blow on camera.

After hitting bottom, Jim (Estevez), always the more productive and capable of the two, cleaned up his act and found a way back. But Artie (Sheen), who never overcame a pronounced inferiority complex in relation to his older brother, passed the point of no return to wallow helplessly in drug-addled dementia. When his constant threats on the lives of his brother and his own ex-wife and kids finally appeared irremediable, Jim decided that a drastic preventative measures -- a mercy killing, from the most charitable point of view -- was the only answer.

Based on a book by David McCumber, script by Norman Snider, Anne Meredith and David Hollander takes the common approach of starting with the stormy night of the 1991 shooting and flashing back to key developmental moments, such as Dad Mitchell punishing the troublemaking Artie and then arming the adolescents and sending them into a debtor's home to threaten him with a rifle.

Come 1967, Jim is studying filmmaking at San Francisco State, where his professor (Peter Bogdanovich) berates him for including so many leering shots of topless women in his student film. In the blink of an eye, Jim is setting up a motion picture studio in a warehouse, where he is soon joined by brother Artie, fresh from two years in the Army.

As their smut business thrives, Artie marries the lovely Meredith (Megan Ward) while Jim goes with good-natured co-worker Adrienne (Danielle Brett), the police raids commence, and the boys spend enough on coke to support a small country. It's the hitherto uncreative Artie who thinks up the concept for ``Behind the Green Door,'' but when the footage he directs proves hopeless, Jim takes over, sending his little brother further down the road of insecurity and resentment.

The Mitchells learn about big business the hard way when the mob pirates ``Green Door'' and grabs most of their profits, and the flop of their 1975 epic ``Sodom and Gomorrah,'' along with dwindling theatrical profits in the face of the video onslaught, provokes the brothers to convert the O'Farrell into a live sex venue, triggering further problems.

Up to this point, the rapid alternation of good fortune and bad, and brotherly relations that volley frequently between spirited partnership and exasperated loathing, keep ''Rated X'' relatively lively despite its generally pedestrian approach. Production values are thin, a sense of time and place barely indicated (entire production was shot in Toronto, hardly a good double for S.F.), and one only has to think of ``Boogie Nights'' to realize how much texture and feeling can be summoned from such similarly seedy material.

But the brother angle does give this story a distinctive dimension, and the brothers Estevez and Sheen, their pates shaved to help them represent the odd-looking Mitchells, do an uncanny, genuinely impressive job. The family tidbits offered up, including the fact that the Mitchells' aging parents were so supportive that they attended the premieres of their boys' films, help suggest their skewed moral sense, and small hints of affection, distrust and other emotions, some no doubt real between Estevez and Sheen, accumulate to create a credible portrait of a deeply problematic sibling relationship.

The women, notably Ward's Meredith, Brett's Adrienne and Tracy Hutson's savvy Marilyn Chambers, all come off sympathetically, and one can only wonder about and wish the best for the various Mitchell kids raised in this environment.

Pic, which has not yet been rated by the MPAA, features numerous soft-core simulations of hard-core sequences from Mitchell brothers productions, but only fleeting full-frontal nudity.

Artie Mitchell .......... Charlie Sheen

Jim Mitchell ............ Emilio Estevez

Lionel .................. Rafer Weigel

Marilyn Chambers ........ Tracy Hutson

Meredith ................ Megan Ward

J.R. Mitchell ........... Terry O'Quinn

Adrienne ................ Danielle Brett

Karen Mitchell .......... Nicole de Boer

Georgia Mae ............. Deborah Grover

Film Professor .......... Peter Bogdanovich

Detective Solly Weiner .. Rodger Barton

Michael Kennedy ......... Geoffrey Blake

George McDonald ......... Jef Mallory

A Showtime presentation of a District production. Produced by Dick Berg, Allan Marcil. Co-producer, Lisa Niedenthal.

Directed by Emilio Estevez. Screenplay, Norman Snider, Anne Meredith, David Hollander, based on the book ``X-Rated: The Mitchell Brothers, a True Story of Sex, Money and Death'' by David McCumber. Camera (Deluxe color), Paul Sarossy; editor, Craig Bassett; music, Tyler Bates; production designer, John Dondertman; art director, James Oswald; set decorator, Brendan Smith; costume designer, Noreen Landry; sound (Dolby SR), John Thomson; assistant director, Laurie Mirsky; casting, Beth Klein, Stephanie Gorin (Canada). Reviewed at Sundance Film Festival (Premieres), Jan. 25, 2000.