Pretty, perky perpetual girlfriend/best friend/second banana Lake Bell makes her second trip behind the feature film camera with a self-written comedy about marriage, “I Do…Until I Don’t.”

It lacks the goofy novelty of “In a World…,” which was set in the insular world of voice-over artists. And she’s still not figured out that comedy requires faster pacing. But she hews close to what she knows — a movie about a movie , a title with an ellipsis — and a winning cast makes the most of its limited possibilities.

A semi-famous British documentary maker, Vivian (Dolly Wells) wants to follow up her edgy cinema verite “Tween Jungle” with a project about the doomed state of marriage in the West. So she’s come to Vero Beach, Florida, to find specimen couples to make her point for her.

“Will you accept that marriage is dead?” She’s convinced “betrothed” means “impending death,” when the true definition — “contract” — would suffice to make her point.

Bell plays Alice, awkwardly married to Noah, and frustrated co-operator of his failing inherited window blinds store. Work isn’t the only place she’s frustrated. She and her husband have sexual peccadilloes that might explain some of their difficulty in conceiving.

Alice is a Vivian Prudeck fan, and she’s determined to get her art degree itch scratched by being in Vivian’s film. She signs them up and lies to Noah about the benefits in order to get him to go along with it. And that’s not the only lie she’s willing to play out.

Her hippy sister (Amber Heard) is in an open hippy marriage with Xander (Wyatt Cenac), and yes, they’re also invited into the documentary’s crucible.

Then there’s the grumpy older couple, semi-retired Harvey (Paul Reiser), who’s just bought a motorcycle, and realtor-at-her-wits-end-over-Harvey Cybil (Mary Steenburgen). She’s got a present for him.

“Is it anthrax?”

The complications here revolve around dishonesty and couples that aren’t in the same places — “open marriage”-wise, retirement-wise, whatever.

And the cute stuff is mostly about Alice trying to find ways to finance her participate-in-the-film dream by taking a job at the “Your Welcome” (sic) massage spa. Sassy Bon Bon (Chauntae Pink) has to explain “happy endings” to naive Alice — “Jerk that elbow to make that bank.”

There’s a funny exchange between Xander and this hippy (Chace Crawford) who hits on his wife, Fanny (Heard) right in front of him. The interloper, just taking advantage of that whole “open marriage” thing, is named Egon.

“Be gone, EGON.” None of this “Namaste” yoga speak for you, pal. “Na mas GO.”

The filmmaker comes off as a big-ol’ lonely phony.

The most crackling interplay is between the Oscar winning Steenburgen — who lets you feel the loathing — and Reiser, who still has the best timing of any comic alive.

The whole doesn’t add up to much more than an ellipsis — an ending foretold by the beginning, and not a lot of funny comic obstacles standing in its way.

But Bell has a beguiling, big-grin screen presence. And her ability to charm a cast into taking on her projects is admirable. Charming a script-doctor or two who could joke the films up would be a big help.

MPAA Rating: R for sexual material and language

Cast: Lake Bell, Ed Helms, Mary Steenburgen, Amber Heard, Paul Reiser, Wyatt Cenac, Dolly Wells.

Credits: Written and directed by Lake Bell . A Film Arcade release.

Running time: 1:43