PARTWAY THROUGH CRAZY HEART, the wildly overpraised new country-music melodrama, falling star Bad Blake agrees to open an outdoor-amphitheater show for his former protégé. It's August in Arizona, and Blake is informed that he's going on at exactly 7:30 p.m. But when he walks on stage, the sky is black. Looks like writer-director Scott Cooper forgot to check his watch.

That single lapse wouldn't be a deal-breaker. The occasional blunder is to be expected on a low-budget picture like this one. But the blunders aren't occasional in this movie, which includes more howlers than it does honest moments. The film has been commended for its realism, authenticity, and so forth. But it rarely hits a correct note.

The hosannas for Crazy Heart illustrate a few tendencies in contemporary film criticism. First, most movie critics don't pay much attention to context or credibility. They tend to be willfully parochial, not just about history, politics, and geography, but also about music. Even though most movies are stuffed with tunes, reviewers seldom notice them, however hectoring or inappropriate. Blessed by this ignorance, critics can applaud the idea of crusty old Bad Blake, who's a less believable music-industry figure than Apollonia's character in Purple Rain.

Second, most critics are besotted with movie stars. Crazy Heart has been hailed breathlessly as the film that might win Jeff Bridges a best-actor Oscar. (And Susan Boyle may score a Grammy. That and $10 will get you a ticket to Leap Year.) Bridges is an engaging onscreen presence, but he does a better job pitching Hyundais on TV than he does in Crazy Heart. His Oscar bid consists primarily of looking scruffy, vomiting on cue, and flaunting his fat, unclothed belly. (And if fat, unclothed bellies win Oscars, then engrave a golden statuette for Alec Baldwin, who's fatter and barer in the pre-fab It's Complicated than Bridges is as Bad Blake.)

Adapted from a novel by Thomas Cobb, but strongly reminiscent of the much-better Tender Mercies, Crazy Heart is a thin porridge of on-the-road-again clichés, made lumpy by country-music gaffes. Bridges's character could be a lot of "outlaw" country types — the movie includes songs by Waylon Jennings and Townes Van Zandt — but his performance is basically a Kris Kristofferson impersonation.

Yet Bad Blake is no Kristofferson. The author of "Me and Bobby McGee" was never reduced to playing small-town bowling alleys — because he was the author of "Me and Bobby McGee" (and other songs that still earn royalties). Bad's also supposed to be a successful songwriter, whose tunes have been recorded by that former protegé, the wildly popular Tommy Sweet (Colin Farrell). So Cooper needs to offer an explanation for Blake's insolvency: Bilked by his manager? Massive alimony? Scientology? There's no backstory that might make the singer's plight believable. The guy doesn't even seem to have a coke habit.

As soon as his slovenly-but-sexy persona is established, the alcoholic has-been pulls into Santa Fe. There he's interviewed by Jean Craddock (Maggie Gyllenhaal), who's supposed to be a reporter with an actual job at an actual newspaper — no small accomplishment these days. But she's an abject amateur whose first question is, "So, how'd you learn music?" Jean doesn't get enough material for a two-paragraph profile, but she does soon crawl into bed with the old rascal.

(You might think that female movie critics would be sensitive to the notion that the typical woman journalist is incompetent, unprincipled, and — to quote Meryl Streep's giddy self-judgment in It's Complicated — "something of a slut." But I've yet to see any complaints about this development. Hollywood loyalists accept that the chick has to have sex with the hero early in the movie; that's the formula, and plausible characterization — let alone professional ethics — just doesn't matter.)

The rest of the movie, principally, is about Bad's struggle to be good enough for Jean. The reporter has a 4-year-old son, Buddy, which adds a predictable dab of conflict: The singer has to prove himself reliable to Jean, and sufficiently responsible for stepdaddy status. Of course, he'll fail the test. Preposterously, Jean lets her whiskey-soaked beau take charge of Buddy. Just to show that his movie isn't cheap, Cooper doesn't have Bad lose track of the boy. Not the first time, that is.

Blake's songs — written by Ryan Bingham, the late Stephen Bruton, and noted Jesus-rocker/misogynist T Bone Burnett — are reasonably clever. A couplet like, "I used to be somebody/Now I am somebody else" can substitute for several pages of dialogue. But Crazy Heart keeps tripping over its own ignorance of the world it purports to depict. At one gig, a true fan tells Bad that "I even know the B-sides of your albums." (Note to script department: Albums don't have B-sides; singles do.)

Ironically, there is a real performance in Crazy Heart, briefly vying with Bridges's look-at-me-I'm-being-unglamorous showboating. It's by Farrell, whose Tommy Sweet shows more depth in a couple of minutes than the star does in a dozen good-ol-boy set pieces. (The scene where Bad goes fishing with Robert Duvall is pure cornbread.) Tommy seems genuinely conflicted when he tells Bad before that Arizona show that he can't do much for him, and when he joins his opening act onstage for a surprise sing-along, the gesture is convincingly double-edged: Tommy is helping his old mentor, yet also upstaging him, and clearly enjoying both. It's a rare moment of clarity in a movie that mostly mistakes haziness for truth.

CRAZY HEART — 2009; 111 min; at Landmark E Street and Bethesda Row and AMC Loews Georgetown.