Billy Famine remembers the “old days” of the East L.A. backyard punk scene in the mid-1990s, when he was a teenager.

“Back then I just had this fascination with just trashing everything and smashing everything,” says Famine.

“Because you’re young, you’re angry, you can break a bone and you just don’t care,” says Famine “If you like punk rock, kids that are angry, primal stuff, backyards are like the place to do it. Nobody’s going to tell you what to do. They’re going to applaud you.”

Famine is in his early 30s now, a punk rock lifer; fan, show organizer and vocalist in the metal-tinged hardcore band Withdrawal Symptoms.

He’s also among the expansive cast of characters who turn up in Angela Boatwright’s documentary, “Los Punks: We Are All We Have.”

“I was so excited by the music and by the fact they’re playing on like dirt hills and backyards and drummers sitting on lawn chairs,” says Boatwright, herself a veteran of punk and metal scenes on the East Coast.

She and her crew spent about four years embedded in the East and South Central L.A. punk scene and befriending the people who propel it.

“If you have the balls to strap on a guitar and go out there and play for people anywhere, then more power to you because I’m not doing it. Just get your noise out and play. That’s the first step,” says Boatwright.

“It’s a way to have a voice and communicate and to go out and play backyard. And you might get $30 for gas and there’s a lot of heart, a lot of passion, so to me that felt important and valid and vital,” says the director.

The film depicts a scrappy, off-the-grid music underworld, one that doesn’t rely on record labels, conventional venues or established promoters.

A sprawling dirt backyard in a gritty working-class Latino enclave like Monterey Park or Boyle Heights will do. News of a show spreads via social media and word of mouth.

“Los Punks” introduces us to kids like April, a 15-year-old backyard show promoter from the south L.A. community of Watts.

“I’m 15,” giggles April in the film. “I’m probably like the only one’s that’s like young in the scene.”

Her age may set her apart, but April shares a lot with her contemporaries in the scene: a conflicted home life, working-class background and living in a community rife with grinding poverty and street violence. But “Los Punks” also captures a fierce DIY, entrepreneurial spirit and a commitment to the scene and the larger community.

So who would let a young kid like Amy transform their dusty backyard into a churning mosh pit for two or three hours on a Saturday night?

Billy Famine says most times it’s just regular people. Working moms and dads, migrant families from Mexico or Nicaragua.

“And someone’s like, ‘Hey, would you like to make some money on the side, because you have a nice backyard. We’re going to give you a cut and hopefully everything goes well,’ ” explains Famine.

“But there are times the house owners are just like; wait, what? This is what you were planning? Was I supposed to tell my neighbors this was going to happen because I think they’re gonna call the cops!”

 Shows rarely tip past 11 p.m. or midnight. But run-ins with neighbors do happen. “Los Punks” captures all of it. Most times, though, the neighbors are pretty cool, says Rooster Cabrillo, vocalist of the band PTSD.

“We had this lady and she didn’t speak any English. And she’s like, well I just don’t want them sitting on the side because they knocking bottles over,” recalls Cabrillo. “You guys can have your party, I just really don’t really want to call the cops because I’m afraid of them.”

Cabrillo is in his early 20s. He was born in Sinaloa, Mexico. He crossed into the U.S. with his parents without papers when he was a child. He’s also gay. Writing and performing music, he says, helped him come out — not just as gay and undocumented but also as an advocate for his community.

“A lot of our songs have to do with mental illness, drug abuse. We even have a song about being queer. I’m queer and undocumented, and so our environments can really mess with our heads,” says Cabrillo.

Director Boatwright reveals who these young people are the morning after a show; struggles with parents, unemployment, mental health or substance abuse, and how they can find a way forward within the scene.

“A million things that can make you angry as young person, you can find solace in punk, hardcore or metal or whatever you like,” says Boatwright. “So I prefer to let the punk explain where they are coming from themselves.”

Sitting just a few feet away from Boatwright during this interview, Rooster Cabrillo hesitantly expresses some apprehension over the film, financed, by Orange County-based apparel and lifestyle company Vans.

“We have a huge problem with gentrification in Boyle Heights right now,” explains Cabrillo. “There’s a lot of folks that love making movies that are from East L.A., who go to backyard shows, and it would have been cool to see them get an opportunity to tell that story for themselves.”

Boatwright says she’s aware of some of the grumbling over the film within the scene, but believes “Los Punks” can actually help open up discussions of issues like gentrification.

“The positive thing that I see coming out of this is that there are some really important discussions being started because of this,” says Boatwright. “And I think if that benefits them to have those dialogues and to better their community, I think that’s great. Then my job has been done.”

Even with more scrutiny from the “outside” world, the scene is unlikely to diminish.

In one telling scene from the movie, the cops break up a backyard show after calls of an alleged stabbing, which turned out to be false. But the kids and the bands were sent packing anyway.

Within minutes though, the text messages are flying back and forth. Another backyard is secured at 83^rd and San Pedro. Gear is hauled off to the new location and the blast of music resumes, roaring  up and out over the rooftops of South L.A.

“Los Punks: We Are All We Have” screens at San Francisco Doc Fest Sunday June 12 and Wednesday June 15 at the Roxie Theatre. The film is also available for download now on iTunes.