Rachel Getting Married is an oddly joyous look at addiction recovery centered on a joyously odd wedding. In other words, it’s the perfect blend of acidic humor and dramatic empathy at which director Jonathan Demme so often excels.

After a detour of documentaries and remakes (the eerily freaky-deaky The Manchurian Candidate), Demme delivers his most deeply felt film since Philadelphia.

Its personal-bubble drama hits heights late-period Robert Altman could only have hoped to scale. The wedding’s musical multiculturalism is an intoxicating aesthetic rather than an indulgent bore. And it contains three of 2008’s best performances — all of which are towering examples of how small-scale minutiae surpass grand gestures.

The 12-step structure isn’t suited to someone who likes taking stairs two at a time. Kym (Anne Hathaway) is kicking most of her chemical vices in rehab, but the hardest is the endorphin rush of attention her addiction brings. To make matters worse, Kym’s testing her rehabbed personality in the worst possible social lab.

She’s headed to her family’s home on the eve of her older sister Rachel’s (Rosemarie DeWitt) marriage to Sidney (Tunde Adebimpe, lead singer for TV on the Radio).

Rachel has long been supportive of Kym’s struggles, even as she resents the comparative spotlight shone on her by their overprotective father, Paul (Bill Irwin). All three share the burden of a distant relationship with Abby (Debra Winger), the girls’ mother and Paul’s ex-wife, and a tragedy in the family’s past.

Rachel avoids the cheap-fraud cynicism of the similarly set-up Margot at the Wedding. Instead, the script by Jenny Lumet (daughter of Sidney) forces its characters, and the audience, to confront these avoidance strategies toward concrete family issues with no easy outs or answers.

Hathaway, DeWitt, Irwin, and, to a lesser extent, Winger all make these wounds well up and freely flow. Playing characters that attempt to cauterize with conversation and understanding, Adebimpe, Anna Deavere Smith (as Paul’s new wife, Carol) and Mather Zickel (as best man and fellow recovering addict Kieran) also excel.

This ensemble creates a feeling of family and fracture that endows Rachel with a real sense of recovery’s fragility and fury — not teary clichés or last-minute reveals.

A rehearsal dinner is so uncannily natural that, were it not for the famous faces, you’d swear it was the home video that Declan Quinn’s rapturously involving cinematography makes it appear to be.

Also in this scene, watching Kym take the first real step toward emotional amends and restitution — masking it underneath cutting satirical humor — it’s clear that Hathaway is letting her usually chipper guard down for a career-best performance.

She’s matched scene for scene by De Witt, a roiling boil of conflicting emotions toward her sister’s health and the desire to have one memorable moment to herself. And Irwin, a stage veteran, conveys paternal pride and, eventually, deflation even in a scene of competitive dishwasher loading — ending the scene with a killer reaction.

Each is worthy of Oscar consideration, but it’s Winger, after a four-year absence from films, getting the biggest buzz. Hers is a performance akin to Ruby Dee from American Gangster — palpably emotional, but brief and showy right down to a slap.

Rachel Getting Married sounds like a downer, but it culminates in a dreamily exuberant wedding-and-reception scene. By examining the slow and incomplete, but true, power of pure rehabilitative strength and forgiveness, Rachel Getting Married is one of the very best films of 2008.