Transferred from the page to the screen, at least in this adaptation by Michael Konyves and Richard J. Lewis, Mordecai Richler’s challenging novel has become a rather pedestrian film, epic in length but curiously pinched in scope. In better circumstances Paul Giamatti might have made the title character the meteorically funny figure he ought to be, rather than merely the standard-issue cad that he is.

Giamatti plays Barney Panofsky, who’s introduced as a sleazy sixty-something producer of a trash TV serial. He’s been suspected for years by a cop (Mark Addy) of having killed his one-time best friend, a writer named Boogie (Scott Speedman), and now the fellow has written a book accusing him of the crime and revealing other lurid details of his life. In Richler’s book, the narrative represents Panofsky’s riposte, a self-defensive biography that tries to absolve him of blame. But the film basically loses the apologetic aspect, simply laying out the episodes of Barney’s admittedly colorful life, though in a chronologically fractured form, with lots of flashbacks. As such it loses a god deal of bite.

What’s left of it derives mostly from Giamatti’s performance, which affords him the opportunity to do his snide-snarky shtick at a variety of ages and weights and with a changing array of facial hair styles. The actor is always fun to watch, but in this case the routine goes on too long and fails to balance the character’s sour selfishness with sufficient goofy charm to make him a pleasing travel companion over the long haul.

The scenario is constructed around Barney’s three failed marriages. The first involves Clara (Rachelle Lefevre), a free-spirited poet whom he meets during his young days in Italy with Boogie. Their union doesn’t last long, ending in acrimony and her suicide. Back in New York, Barney’s introduced to a wealthy Jewish princess (Minnie Driver), whom he weds. But at their wedding reception he meets beautiful, intelligent Miriam (Rosamund Pike), and is immediately smitten. He pursues her even while trying to maintain a life with his wife, though that acrimonious relationship eventually comes to an end when he catches her in bed with Boogie one afternoon. It’s in the aftermath that Panofsky confronts Boogie and the latter winds up dead—but whether it was murder is another question.

Barney’s marriage to Miriam involves a couple of children and some years of happiness, but it’s undone by Panofsky’s jealousy over her friendship with Blair (Bruce Greenwood), an articulate radio executive who offers her opportunities in journalism. That leads to divorce and Barney’s descent into crabby irascibility in both his professional and personal life, as well as increasing forgetfulness that could be the sign of serious mental deterioration. It’s at this point that his old nemesis from the police reenters the picture—though a last-act revelation settles his charges, even though not in the way either he or Barney expects.

There’s plenty of opportunity for sharp satire here, but it’s mostly flubbed. Konyves hasn’t successfully translated Richler’s attitude into cinematic terms, and Lewis directs flatly, failing to find a visual equivalent for the book’s verbal dexterity. Still, one can enjoy the performances—Giamatti’s for its exuberant misanthropy, Driver’s for its unabashed shrillness, and Pike’s for its quiet radiance—as well as the flamboyant turn by Dustin Hoffman as Barney’s coarse, knowing father. By contrast Scott Speedman’s attempt to capture Boogie’s extravagance comes off as forced. And though Guy Dufaux’s cinematography doesn’t always make the best use of them, the locations are nice.

The makers of “Barney’s Version” obviously treated the source novel with respect. Unfortunately, respect without imagination wasn’t enough.