After six commercially and critically successful albums crisscrossing through hip-hop, R&B, rap, soul, pop, rock and urban street sounds, leave it to OutKast to try and do something completely different. While both André Benjamin (a.k.a. André 3000) and Antwan A. Patton (a.k.a. Big Boi) aren’t exactly new to movies, their 1930’s Prohibition musical melodrama “Idlewild” still marks their debut as top of the line stars. Working with frequent video director Bryan Barber (who also wrote the script), this film is an outlandish, over the top visual phantasmagoria full of wickedly sublime imagination and musical beats unlike anything else this year.

If only the rest was as richly satisfying as the trio’s visual ingenuity and genre-bending determination. “Idlewild” is a total crock, a deeply ponderous foray into cliché enlivened only intermittently by a string of whimsically eccentric musical numbers that, at times, completely blew my mind. But not always, a few of them are surprisingly tepid, many of Patton’s in particular coming off as forced, false and not at all interesting. In all honesty, a couple of his songs are just plain bad, and coming from one half of a performing duo that’s always made me giddy this is a disappointment too horrendous to bear.

Barber’s plot is strictly run of the mill. By night, childhood friends Percival (Benjamin) and Rooster (Patton) work together at a popular speakeasy called Church, the former playing the piano while the latter wows the ground as the headliner. By day, however, Percy works with his father (Ben Vereen) at the family mortuary while his friend assists local bootlegger Spats (Ving Rhames) with bringing in his alcohol shipments.

All this changes with two events, the first being the arrival of new singer Angel (Paula Patton) and the second the murderous intentions of Spat’s second lieutenant Trumpy (Terrence Howard). While the former weaves an erotic spell around Percival, the latter guns down both his boss and Church owner “Sunshine” Ace (Faizon Love) in cold blood leaving Rooster in charge of the club. Now both have to face up to their demons, music the revelatory tool both use to extract their ultimate salvation. (If this sounds suspiciously like Eddie Murphy’s ill-fated “Harlem Nights,” trust me, you won’t be the only one to make the comparison.)

In all actuality this could work. The problem is, Barber fills his screenplay with far too much stilted dialogue and cliché dramatics for it to come off as anything other than a gigantic mess. Audience members laughed brazenly at the screen during the most inopportune moments, and pardon me if I couldn’t help but want to join in with a snicker or two of my own when things started reaching their most painfully idiotic. At one point a character’s good dead earns him a bible from a kindly old woman, a bible which he then puts up against his heart in his right vest pocket. You tell me what happens next.

This could all be forgiven if the individuals in the key roles were better performers. Of the central trio (Percival, Rooster and Angel) only Benjamin proves to be an actor. But then, from his scene-stealing work in the otherwise forgettable “Be Cool” and “Four Brothers” we already knew that. What we didn’t know was just how bad an actor Patton was. While I did not see “ATL,” if the rapper is anywhere near as stiff and wooden there as he is here I can only imagine his scenes in that film would be like watching paint slowly, almost painfully, dry.  As for newcomer Patton, she’s definitely a stunningly gorgeous pretty face, but as far as her acting is concerned the less I say on that front the better it would probably be.

And yet, I cannot write “Idlewild” off completely. The supporting actors are all excellent (especially a menacingly shifty Howard), and there is something passionately touching about Percival’s relationship with his grieving father. Even better are those surreal musical numbers, especially one featuring Benjamin and wall of giant cuckoo clocks, while an end credits big band set piece is as explosively entertaining as anything I’ve seen all year. (It goes without saying that Hinton Battle’s choreography is stunning, while Charles Breen’s first rate production design and Shawn Barton’s fabulous costumes dazzle.)

But whereas Barber stages the musical numbers as ingeniously as the groundbreaking music videos for which he’s justifiably been lauded for, the rest is an unfocused herky-jerky haphazardly realized disaster. The editing is slapdash, while the director can’t seem to figure out the appropriate place for his camera during a single one of the picture’s more dramatic moments. Too bad, because the potential for something fresh, original and daringly new beats within this film’s syncopated heart. Instead, “Idlewild” is a mess, a musical debacle just waiting for someone to turn down the volume on its disappointing histrionics.