In the pre-YouTube era it would’ve been passed between friends on a well-worn videotape: a three-minute clip from 2002 of the Australian rock band the Vines demolishing the set of David Letterman’s show following -- well, during -- a performance of the group’s hit single “Get Free.”

Today it’s easy to find -- just search for “Vines live meltdown” and you’ll pull up footage that’s been viewed more than 250,000 times since it was uploaded in 2006.

Part of the neo-garage scene earlier this decade that made stars out of the Strokes, the Hives and the White Stripes, the Vines -- and, in particular, the group’s frontman, Craig Nicholls -- nearly instantaneously established a reputation as out-of-control bad boys known for combative interviews, chaotic live shows and a marijuana-and-McDonald’s diet that might’ve given a young Mick Jagger pause.

The Letterman video seemed like solid evidence of Nicholls’ desire to join rock ‘n’ roll’s hall of shame. Yet in 2004 the singer-guitarist revealed that he has Asperger’s syndrome, a form of high-functioning autism characterized by “deficits in social interaction and unusual responses to the environment,” according to the Yale Developmental Disabilities Clinic.

“The guy who diagnosed Craig said his life consisted pretty much of the worst things you could do for someone in his condition,” says the Vines’ manager, Andy Kelly. “Being in a different place every day, meeting new people, just having everything be totally unstructured. Things went downhill very quickly.”

At the time of Nicholls’ diagnosis, Kelly and the band’s other handlers expressed doubt that the Vines would ever tour again. Soft sales of the group’s last album, 2006’s “Vision Valley” -- which to date has sold just 25,000 copies in the U.S, according to Nielsen SoundScan, compared with almost 700,000 for its 2002 album, “Highly Evolved” -- lent weight to the idea that perhaps the Vines’ moment had passed.

But after Nicholls began treatment for a disorder that many think goes a long way toward explaining his volatility, the Vines are back with a new album and a small-scale series of live dates. Last week the quartet played the South by Southwest conference in Austin, Texas, and tonight it has a sold-out show at the Troubadour. Nicholls calls the activity the beginning of a new chapter in the Vines’ story.

“It’s going to be a lot different this time,” he says, hanging out with drummer Hamish Rosser and guitarist Ryan Griffiths at Hollywood’s Sound Factory recently, the day after completing mixing the currently untitled album with producer Rob Schnapf. (The band’s new bassist, Brad Heald, was at home in Australia.) “We feel a lot more confident. I feel like everything’s going to be OK, and I’m going to get to keep making music.”

Whereas he once famously locked himself in a bathroom during an interview with England’s NME, today Nicholls, 30, is a portrait of youthful enthusiasm, air-drumming as he plays back a handful of tracks from the just-finished record.

The new songs offer the band’s signature mix of loud grunge guitars and Beatles-influenced melodies; one track features an elaborate string arrangement and a lyric that finds Nicholls admitting, “I stand alone inside.” The frontman calls the music “psychobilly pop-punk balladry,” which seems about right.

Schnapf, who produced the new album as well as the Vines’ first two, described Nicholls as “way more focused and self-aware” than in the past. But he also admits that some of Nicholls’ artistic ability could be enabled by Asperger’s.

“With most of us, you have an idea, some kind of primal impulse, and it gets put through the filter of your brain and then you open your mouth and it comes out,” Schnapf says. “With Craig, the primal thing just shoots right out. It’s unfiltered, and that’s the really cool part.”

Former Capitol Records President Andy Slater, who along with the Vines was dismissed from the label during last year’s merger with Virgin Records, said he signed the band because Nicholls was a “great record-maker and songwriter,” not because the Vines were a proven touring act.

“Craig was always true to who he was,” Slater says. “There were never any showbiz shenanigans with him, and that’s why I never felt betrayed as a business partner. Sometimes artists operate in a fourth dimension where they’re able to communicate things through a painting or a song, even though they can’t go to the dry cleaners and get their stuff. I’m sure Capitol Records had issues with Brian Wilson in the ‘60s. You just have to be patient.”

For the moment, the members of the Vines are the ones whose patience is being tested. The new album is set for a June release in Australia through Ivy League Records, which is run by Kelly and his business partners.

The band doesn’t have a deal to release the record in the U.S., but Kelly says he’s in talks with a variety of interested labels, both major and indie, and he expects those talks to escalate after the Vines’ performances here and at South by Southwest.

“I’d call it cautious interest,” Kelly says with a laugh. “A lot of the people we’re speaking to have loved the band’s albums, but have their worries because of Craig’s behavior in the past. We can tell them it’s different now -- that it’s consistent -- but they need to see it for themselves.”

According to Nic Harcourt, host of KCRW-FM’s influential “Morning Becomes Eclectic,” the band still commands a sizable fan base from its first two records.

“The people that were there before are still there,” Harcourt says. “I’m intrigued, and at the end of the day, if they have the songs the interest will be there.”

Nicholls says he’s happy enough with the band’s new music to feel that he’s already staged a successful comeback.

“This time we’re not looking for hype,” he says. “We put a lot of hard work into the album, but I hope people don’t have to think too hard about the songs. I just want to brighten the world in some small way.”

He grins.

“Even though there’s some death-metal songs on there.”

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The Vines

Where: Troubadour, 9081 Santa Monica Blvd., West Hollywood

When: 8 tonight

Price: Sold out

Contact: (310) 276-6168