Whenever I’m confronted by rap music (something that’s increasingly difficult to avoid, given the propensity for using it to give oomph to movie soundtracks), I can’t help but be reminded of the couplet with which Captain Corcoran dismisses Little Buttercup’s string of cliched prophecies in Act Two of Gilbert and Sullivan’s “H.M.S. Pinafore.” “Though I’m anything but clever,” he mutters in an aside, “I could talk like that forever.” Rap is often referred to as street poetry, but surely such a description denigrates serious verse. It seems little more than doggerel, no more impressive than the sort of silly ditties Ogden Nash used to produce by the ream, but featuring lots of vulgarities and glorifications of violence, and usually set to a throbbing, repetitive musical beat (perhaps to assist listeners to perceive the rudimentary meter).

Still, whether you appreciate its virtues or not, you can’t deny rap’s popularity and influence; so it’s entirely understandable that Hollywood, ever on the lookout for money-making opportunities, should attempt to extract some profit from it. Previous efforts along that line have been mostly unfortunate–anyone remember “Cool As Ice”?–but the latest example at least has an estimable pedigree. “8 Mile”–a title that refers to a street in Detroit that separates the largely-black inner city from the largely-white suburbs–is directed by Curtis Hanson (who won an Academy Award for co- writing “L.A. Confidential,” for the direction of which he was also nominated, and later directed the underappreciated “Wonder Boys”) and co-stars Kim Basinger, who won an Oscar for her performance in “Confidential.” Unfortunately, they’re working from a script by Scott Silver (“The Mod Squad”) which basically recycles all the old, tired cliches that abound in every story about the rise to stardom of poor but talented youngsters who overcome terrible obstacles in their drive to succeed. Is it surprising, for instance, that initially the protagonist, given the absurdly generic name Jimmy Smith, chokes every time he’s supposed to perform publicly? Or that to show his softer side, he’s provided with a sugary-sweet urchin of a sister, whom he protects and nurtures at every turn? The picture even closes with a instant-elimination rap tournament–sort of a musical version of the kickboxing spectacles that always concluded Jean-Claude Van Damme’s early starring forays. Curiously enough, though, the script, while it contains all the standard elements, doesn’t join the seams very successfully; there are spots where chunks of narrative seem to have been arbitrarily excised, giving the story a slipshod, unfocused quality. The grubby Motown atmosphere and rap ambiance are nicely caught by cinematographer Rodrigo Prieto, and one has to admire any film that deals–as so few American ones do nowadays–with the all-too-forgotten economic underclass, but they’re not sufficient to give the entirely predictable result much distinction, despite the slickness Hanson and company bring to the table.

Nor does the debut turn by Eminem (aka Slim Shady and Marshall Mathers) raise it above the humdrum. The list of pop music icons who have successfully made the transition to film actors is even shorter than that of TV stars who’ve become above-the-title names on the big screen. There was Frank Sinatra in an earlier era, and then Elvis, of course–although it would be difficult to argue that he ever grew into a thespian in any meaningful sense. If his work thus far is any indication, Jon Bon Jovi has an outside shot. And there was…Prince? Well, you get the idea. Happily Eminem doesn’t prove a second Vanilla Ice, but he’s no instant breakout star, either. Of course, the fact that he’s surrounded by so many savvy people behind the camera helps, but while it might prove to be a one-time fluke, in this instance the rapper shows some basic presence on celluloid, too. (Oddly enough, in his favorite stocking cap he looks rather like Ben Foster, who’s had lesser roles in a few features; and though he doesn’t have Foster’s range, he does evince a certain smoldering intensity that fits his driven, conflicted character here.) Basinger, unfortunately, is far too broad as his heavily-accented trailer-trash mother (her abrupt transformation toward the close is completely preposterous), and Brittany Murphy doesn’t bring much beyond a pretty smile to the proceedings as a streetwise groupie, looking for a ticket to New York, whom Smith romances. Eminem is better served by the guys who play his pals, though the characters are all cliches. Mekhi Phifer is the wise, avuncular rap master of ceremonies who believes in Smith’s genius; De’Angelo Wilson cuts the right prissy pose as the intelligent, bespectacled dude; Omar Benson Miller is the oversized, jolly fellow; and Evan Jones proves a decent younger version of Steve Zahn as the fumbling, dense white guy who tags along with them. Everybody else passes muster but little more–though Michael Shannon abets Basinger’s overstatement as Ma Smith’s young, sleazy live-in boyfriend.

There’s already been some extravagant critical praise for “8 Mile” and Eminem’s work in it. That’s puzzling. The film and its star are certainly better than might have been feared, but the result still doesn’t rise above mediocrity. Eminem barely manages to crack a smile through the whole of “8 Mile,” and as it turns out, his picture doesn’t give viewers much to smile about, either.