On a Friday night last month at UCLA’s Royce Hall, British conductor John Wilson led a 97-piece orchestra and 36-voice choir in two hours of selections from classic MGM musicals. By the end of the performance, an invitation-only crowd of 1,000 industry movers and shakers were on their feet, cheering and shouting for more.

Four nights later, across town at L.A. Live’s Nokia Theater, the applause was even more deafening for the first of three performances showcasing Danny Elfman’s music for Tim Burton movies. This time, it was 6,000 fans listening to 87 top Los Angeles musicians (with 45-voice choir) conducted by longtime Hollywood Bowl baton-holder John Mauceri, with Elfman himself singing songs from “The Nightmare Before Christmas.”

Later the same week, the San Francisco Symphony played Bernard Herrmann’s scores for “Psycho” and, in a world premiere, “Vertigo.” Both were presented “live to picture,” meaning the films were stripped of their original recorded music so that the symphony could accompany them as the films unspooled.

Orchestras everywhere are jumping onto the movie-music bandwagon, thanks in part to the built-in marketing hook provided by film titles, particularly classic pics. And the concert treatment is helping to bring overdue respect to filmdom’s finest scores.

The New York Philharmonic recently played Stanley Kubrick’s classical music selections for “2001: A Space Odyssey” as the film played above the stage in Manhattan’s Avery Fisher Hall. All three “Lord of the Rings” movies have now been screened with live orchestral and choral accompaniment; and “The Wizard of Oz” is fast becoming a staple of family-friendly, live-with-orchestra symphony events.

“I don’t think it’s a vehicle for nostalgia, or just for the generation that saw these films,” says Wilson, whose own orchestra has been performing classic film music in the U.K. for nearly 20 years. “The very best of this music can be accepted on its own, purely musical, terms.”

Original film scores, long derided by critics and academics as hack work unworthy of performance apart from its cinematic origins, has gained respect in recent years, in part because of the unprecedented popularity of John Williams and his frequent performance of often sophisticated music from many of his films. (The all-Williams “Star Wars in Concert” tour played to sold-out audiences in England and North America in 2009-11.)

Mauceri, during his 15-year tenure as principal conductor of the Hollywood Bowl Orchestra, supervised the creation of dozens of new film-music suites, making Golden Age Hollywood scores playable in concert for the first time. And as Bowl Movie Nights began in the late 1990s, some of them were performed with film excerpts.

The biggest boom has been in the screening of complete films with orchestral accompaniment. Steve Linder, senior VP of IMG Artists, cites the Los Angeles Philharmonic’s 1987 performance of “Alexander Nevsky” (with Andre Previn conducting Prokofiev’s landmark score live to picture) as the “light-bulb moment” when he first realized the commercial potential of music and image for concert audiences.

“Clip shows have now transmuted themselves into full-film evenings,” he says, noting that “Live From Lincoln Center” producer John Goberman (who produced the original “Nevsky” evening) has turned the conceit into a cottage industry, with live-orchestra shows of “Oz,” “Casablanca,” “Singin’ in the Rain,” “Psycho” and others. (Wilson reconstructed the lost “Oz” score for Goberman.)

The Elfman-Burton concert was co-produced by Elfman’s agents, Kraft-Engel Management with Columbia Artists Management.  Based on the success of this initial concert, the two companies are joining forces for more film music related shows.

IMG Artists has partnered with the Gorfaine/Schwartz Agency, which specializes in repping film composers, to present live-to-picture concerts of films done by GSA clients. The first will be “Home Alone,” premiering Dec. 18, with the Cleveland Orchestra, directed by David Newman, performing the Williams score for the 1990 John Hughes film. Starting next summer, IMG and GSA will offer both “Star Trek” and “Star Trek Into Darkness,” two Michael Giacchino scores for the J.J. Abrams rebooted franchise — and there are plans for more.

Newman is among the most active of conductors doing films live in concert. Over the past two years, he’s conducted performances of “West Side Story” in concert halls from New York to Sydney, and discovered that the musicians were as enthusiastic as audiences, despite the high degree of difficulty of the Leonard Bernstein score. Newman is also the regular conductor of the Hollywood Bowl’s Movie Nights, which routinely include live-to-picture excerpts.

Mauceri finds the reason some musicians love playing movie music is that it’s what they grew up with. “They’re actually playing the real notes of the first orchestral music they ever heard as kids,” he says. Older musicians have come around more slowly, he adds, because many “were trained in conservatories to hate this music.”

Steven Allen Fox founded the Golden State Pops Orchestra in 2002, with the specific intent to play what he calls “media music” in concert (as well as TV music and videogame scores). He sees such work as a great way to introduce audiences to the symphony. “Film music is an art form, and needs to be treated that way,” he says. “It shouldn’t be thought of as second rate.”

Mauceri views the best of recent such music as “contemporary classical music,” as valid as any written by the classical greats of the past century. “The bottom line is,” he notes, “this is the orchestral music that’s been heard by more people than any music in history.”

(Pictured: Danny Elfman joined John Mauceri and the Hollywood Symphony at an L.A. concert of his work.)