‘L.A. Plays Itself’ is finally coming to home video. Here’s how.

“Los Angeles Plays Itself,” CalArts professor Thom Andersen’s dazzling documentary chronicling the way movies have represented (or, more often than not, in Andersen’s view, misrepresented) the City of Angels, has been shown almost annually by the American Cinematheque since its 2003 premiere. And whenever it pops up — usually on a holiday weekend because it’s always a big draw — it’s duly noted that the movie will never see the light of day on home video because it’d be impossible to clear the rights to the 200-plus films glimpsed in its near-three-hour running time.

So when the Cinema Guild recently announced it would be releasing “Los Angeles Plays Itself” across home and digital platforms on Sept. 30, a cry of victory and disbelief went up among movie lovers. How is this possible, people wondered. Nobody was asking “What took so long?” because we thought we knew the answer, though, as it turns out, that answer had always been wrong.

Ten years ago, around the time it debuted at the Toronto International Film Festival, Los Angeles entertainment attorney Michael Donaldson combed through “Los Angeles Plays Itself” frame by frame and told Andersen that the use of those scenes was all covered under the definition of fair use, which allows the inclusion of copyrighted material without permission.

“I looked at every single clip, and it was rock-solid fair use then, and it’s rock-solid fair use now,” Donaldson says. “Every clip he used was to illustrate a point he was making about Los Angeles, whether it be Los Angeles as the setting for a film or Los Angeles as a character in the film or a Los Angeles story being told cinematically.”

Donaldson knows the legal territory well. He helped create a fair use guide in 2005 for documentary filmmakers and has since reviewed dozens of movies, telling clients what they need to do to avoid lawsuits from copyright holders. Donaldson fought for Rodney Ascher’s “Room 237,” a look at film fans’ theories about the messages Stanley Kubrick may have embedded in “The Shining.” He kept Disney at bay on “Escape From Tomorrow,” a low-budget horror satire filmed on the sly in Disney theme parks. And he successfully defended “Expelled: No Intelligence Allowed,” the 2008 screed against “big science,” for including 15 seconds of the John Lennon song “Imagine.”

Fair use in movies comes down to three questions: Is the clip illustrating an idea that the filmmaker is trying to make in the new work? Is the clip being used in a reasonably appropriate manner? And is the connection clear between the clip and the point being made? If the filmmaker can answer yes to all three questions, then, Donaldson says, it’s fair use and the movie can be insured against lawsuits.

That doesn’t mean people won’t get upset. Donaldson has handled two lawsuits against his clients (Lennon’s widow, Yoko Ono, sued over “Expelled” but lost) and fielded a number of angry phone calls, some of them prompting filmmakers to add disclaimers or shell out a little cash to avoid legal action. On “Room 237,” Kubrick’s estate was eventually placated with a lengthy disclaimer that, on screen, usually results in one of the movie’s biggest laughs because it just keeps going ... and going ... and going.

The disclaimer’s length runs counter to the economical way Ascher uses clips from “The Shining,” often pausing the scene or slowing it down while one of the movie’s chatty interview subjects argues a point about Kubrick’s film. This technique makes it appear the scenes are playing longer than they actually do, which, Donaldson says, helps Ascher’s film meet fair use requirements.

“The only thing that makes that film — or Thom’s film — come alive are the clips,” Donaldson says. “But if you had to license those clips, you could never pay for the film. So that’s why we have fair use. In fact, that’s why we have copyright. The U.S. Constitution, which gives Congress the power to make copyright laws, also tells why they have that power. And it’s to encourage artists to create new works.”

Which brings us back to “Los Angeles Plays Itself.” If Donaldson gave Andersen the legal all-clear a decade ago, why didn’t Andersen pursue a distribution deal more aggressively?

Reached by phone at his Silver Lake area home, Andersen listens patiently and then requires a little patience as he answers questions in a roundabout manner, full of long pauses and a few dead stops. He says that, as a filmmaker, he had reservations about the quality of some of the clips used in “Los Angeles Plays Itself,” but now that the film has been remastered with high-definition source material, he’s satisfied — at least, “for the time being.” He says a few distributors had inquired about a home video release over the years, but he didn’t want his life “destroyed by a lawsuit.”

“I’m not rich,” he adds. “I’m poor.” And that frugal mind-set could explain why Andersen balked at paying the insurance premium (cost: around $3,500) that would have (or, at least, could have) given him the assurance that copyright holders wouldn’t come after him.

Not that he seems to harbor any regrets. Over the years, Andersen has always enjoyed attending and talking to audiences at the special Cinematheque screenings of his movie. “Room 237’s” Ascher was there one year and, in an email, calls “Los Angeles Plays Itself” the “perfect blend of two genres of film I’ve always loved, the documentary and the ‘found footage film.’”

Andersen happily returns the compliment, calling “Room 237” and other films about Hollywood one of the happier movements in cinema in recent years. And it’s only possible, he says, through a more generous interpretation of fair use.

“These movies being discussed are part of our common cultural heritage, and if the people who own them don’t recognize that fact, then you have to act without them,” Andersen says. “There have always been movies about movies, but it’s only recently that a critical discourse has been possible. And that’s good for everyone.”