Condensing an eventful, famous life into a movie that lasts a few hours is always a tough task. Not surprisingly, successful biopics of the past decade have tended to instead concentrate upon specific, pivotal periods of their subjects’ lives. That goes for 2012’s “Lincoln,” 2010’s “The King’s Speech” and 2005’s “Capote.”

Last year’s “42,” a biopic about sports great Jackie Robinson, the first black athlete in major league baseball, followed suit. Like “42,” “Get On Up,” a biopic about “Godfather of Soul” James Brown, stars Chadwick Boseman in the leading role. But unlike “42,” “Get On Up” traces Brown’s life from his poor childhood in rural South Carolina through his stardom and into his later years.

“Ray,” Taylor Hackford’s 2004 movie about Ray Charles, likewise covered its subject’s life from rags to riches. But “Ray,” featuring Jamie Foxx’s Oscar-winning performance as Charles, is a far more authentic portrait of the artist.

In “Get On Up,” events in Brown’s life are tossed onto the screen in jumbled chronology. The filmmakers make reckless choices about what to put where. Time and place jump and dance nearly as much as the real Brown did on stage.

It’s disconcerting, too, that Boseman’s Brown turns to the camera to speak directly to the movie audience. In film and theater, it’s called “breaking the fourth wall.” Previous successful examples include Matthew Broderick in “Ferris Bueller’s Day Off” and Woody Allen “Annie Hall.”

Boseman smiles brightly into the camera. He addresses his imaginary audience with ease and charm. But in a film struggling with narrative difficulties, breaking the fourth wall undermines the project’s credibility further, effectively taking the audience out of a story that’s already difficult to follow.

With Boseman as Brown, “The Help” director Tate Taylor at the helm, Oscar nominee Viola Davis and Oscar winner Octavia Spencer in supporting roles and Mick Jagger co-producing, “Get On Up” would seem to be an instant winner. The finished film, however, is a disappointing interpretation of Brown’s hugely successful, influential yet troubled life.

Bracketed by a falsely theatrical, late-in-life walk Brown makes alone in backstage shadows, the middle of the movie focuses on Brown’s troubles more than his triumphs. That’s a fundamental misstep. Brown raised himself from poverty and abuse to become one of the biggest stars in music and among the most famous men in the world. Yet in “Get On Up,” Brown’s music and the development of his talent get just passing, superficial attention.

“Get On Up,” like many films that prominently feature music, struggles to recreate in-concert excitement. “Ray,” for instance, which has scenes shot at New Orleans theaters including the Civic, Orpheum and Saenger, looks and feels vastly more authentic than the Mississippi-shot “Get On Up.” Although reproducing the electricity of Brown’s legendary shows is impossible, the obviously staged in-concert scenes in “Get On Up” don’t come close.

Biopics are always risky, especially when their subjects are as famous as Brown. “Get On Up,” lasting a long two hours and 18 minutes, can’t touch the star it tries to represent.