James Murphy understands music and also consumer behavior, a rare combination these days.

Until last year he was the engine behind LCD Soundsystem, the great New York band devoted to dance-punk revival and wry self-assessment in the face of cruel aging. Murphy plotted its demise carefully. Shrink supply, he knew, and demand is stoked. Announce your funeral, and it can fill Madison Square Garden.

That's exactly what happened on April 2, 2011, when the band played its sold-out final concert there, an affair documented in the lavish and inconsequential documentary "Shut Up and Play the Hits."

Murphy's decision can't help being read as a defense against a natural, insignificant death, a forestalling of one's mortality. This was a controlled way to end a career and a hubristic way of pulling the trigger, rooted in the belief that the funeral would be worth attending. And filming.

The corpse, as it happens, was beautiful. Directed by Will Lovelace and Dylan Southern, "Shut Up" is graceful in its depiction of the performance, neither uncomfortably intimate nor shy.

It's the rare concert film that goes out of its way not to flaunt the size of the audience — most of the camerawork is up close, emphasizing details that many there would have missed, giving it the feel of a small-room performance or a conversation among friends (though there are some impressive overhead shots of the crowd vibrating like testy electrons).

Murphy and his bandmates and guests don't do much onstage, so the weight of the film often falls on the concert's sound, which, as mixed by Murphy, has an intense physicality to it, crisper than it was in the building that night. (As Murphy might put it, I was there.)

Even though sound is the best weapon available to them, the directors make efforts to elevate "Shut Up" beyond a traditional concert film: interview segments with the journalist Chuck Klosterman, footage of Murphy in and around his apartment the morning after the show. But they're scant and largely empty.

Murphy comes off as an amiably rumpled gentleman — whether in a tux onstage at the Garden, or in pajama bottoms and slippers, walking his dog — who is more content to be on camera than to speak to one. Klosterman, who writes the Ethicist column for The New York Times Magazine, often has more to say than he does.

A scene in which Murphy weeps while surveying the band's gear the day after the concert is meant to be the film's catharsis, but it's cold, and it's such an emotional outlier that it feels staged.