Documentaries can be snoozy parades of talking heads sprinkled with grainy performances. "Anita O’Day: The Life of a Jazz Singer," playing at the Lagoon through Thursday, works for several reasons: the snappy, keep-things-moving way it’s put together; the candidness with which O’Day speaks; the songs and the ephemera: album covers, ads and vintage clips zoom by, sometimes on split screens.

Here’s the trailer on YouTube.

It’s fascinating to watch O’Day grow as an artist from her early days with Gene Krupa to her astonishing performance at the 1958 Newport Jazz Festival, and it’s moving to learn of her 15-year heroin addiction. She finally kicked it on a beach in Hawaii. When she got the chills, she’d lie on the warm sand in the sun; when she got the sweats, she’d go into the ocean. Maybe Hazelden should open an office on the Big Island?

We see an artist who lived very much in the moment — from one gig to another, never looking back, no regrets. We learn the basics about her parents, skim the surface of her marriages, and catch glimpses of John Poole, the handsome drummer who first put a needle in her arm. There’s a terrific scene during an interview with an arrogant Bryant Gumbel, where O’Day smacks him down. And there’s music: her swinging "Let Me Off Uptown" duet with trumpeter Roy Eldridge from 1941, a time when white women did not perform with black men and certainly didn’t tease them on stage; her impeccable sense of rhythm and effortless scatting; "Sweet Georgia Brown" at Newport; her poignant final performance filmed shortly before she died in 2006.

Worth seeing, and the popcorn is good.

Lagoon Cinema, daily through Thursday Dec. 18. Shows at 2 p.m. and 7:30 p.m.