“If These Walls Could Talk,” a documentary about the Punchline Comedy Club

Available on iTunes as a download purchase ($12.99) or streaming rental ($4.99). On Google Play, downloads are $7.99 and rental $3.99. You can also pick up the DVD ($14.95) at the club, 280 Hilderbrand Drive, Sandy Springs.

From the outside, the Punchline Comedy Club in Sandy Springs seems just another drab building amid a sea of asphalt. The inside, with its dated wood paneling, evokes an aging country western bar from the “Urban Cowboy” days. The walls feature decades-old 8-by-10 black-and-white photos of comics, some famous, most forgotten.

Despite the atmosphere — or because of it — the beloved comedy institution endures as it enters its 33rd year of existence this week. It remains one of the oldest stand-up comedy clubs in the country.

Steve Mitchell, a retired radio broadcaster who manned the airwaves on now-deceased stations 96rock and Eagle 106.7, spent three years chronicling the history of the club, calling his documentary “If These Walls Could Talk.”

“When I started doing interviews with comics in 2010, Jimmy Shubert said the line, ‘If these walls could talk,’” Mitchell said. “It didn’t register. A year later, another comic said the same thing. Then a third comic did, unprompted. By the time John Oliver brought it up, I knew that had to be the title.”

The club’s dingy, beer-splattered walls have heard the voices of thousands of comics and the laughter they’ve evoked. A sampling: Jerry Seinfeld, Tim Allen, Jay Leno, Roseanne, Jeff Foxworthy, Dave Chappelle, Larry the Cable Guy and Louis C.K. Earlier legends such as Robin Williams, Eddie Murphy and Richard Pryor have graced the tiny stage.

“It’s a living museum,” Mitchell said. “The people in Atlanta have been coming here so long, yet they may not know its history. They are lucky to have it. It’s not known for its food or its decor but it’s a magical atmosphere.”

Comedians in the documentary are rhapsodic about the club’s charms, how the laughter bounces warmly off the walls, how supportive the crowds can be. Mitchell includes in the 78-minute documentary archival stand-up bits from the 1980s (“There are a lot of mullets!”) and a sampling of current acts.

Foxworthy, who lives in Alpharetta, famously started his career at the Punchline on amateur night in 1985. In the documentary, he stands on that same stage more than a quarter-century later to tell his story.

“After the thing, this girl said, ‘You were funny,’” he said. “She ended up becoming my wife. … Kind of met my career and my wife in the same room, same building, same night.”

Mitchell was most struck by the comments of Oliver, the stand-up who recently left his correspondent’s gig on “The Daily Show” to start his own HBO comedy show. Oliver grew up as a student of comedy in Britain and had read about the Punchline as a mecca for stand-up. He was thrilled to perform there.

“It’s my Narnia,” Oliver told Mitchell. When told that bits of Gallagher’s watermelon remnants had been recently scraped off the ceiling, Oliver chuckled. “Gallagher smashed watermelons on this stage,” he said. “I’ve made it. We all have our heroes!”

Punchline co-owner Chris DiPetta, an assistant manager when the club opened in 1982, embraced the project and helped fund it. The film is available on iTunes and Google Play. He is trying to convince Showtime to air the film.

As for the club itself, he would love a bigger space. (The current building capacity is about 275 people.) But he said it’s hard to leave: “I’m stuck with this building. I’m afraid to move it. There’s so much history.”