NEW YORK, NY.- David James Rosen’s work has been streamed on YouTube hundreds of millions of times. He’s played a crucial role in some of pop culture’s biggest recent moments. But few people outside the space where the entertainment and marketing industries overlap know his name.

As a composer, Rosen is at the forefront of the trailerization movement: He’s in demand for his ability to rework existing songs to maximize their impact in trailers for films and TV shows.

He married vocals and motifs from Kate Bush’s “Running Up That Hill” to a thunderous version of the “Stranger Things” theme in the lead-up to the second volume of the show’s fourth season. He intertwined Nigerian singer Tems’ cover of “No Woman No Cry” with Kendrick Lamar’s “Alright” in the teaser for “Black Panther: Wakanda Forever,” symbolizing the meeting of the franchise’s future and its legacy. He put a sinister singe on Taylor Swift’s “It’s Nice to Have a Friend” for the diabolical doll thriller “M3GAN.” He added cosmic drama to Elton John’s classic rock staple “Goodbye Yellow Brick Road” for the upcoming “Ant-Man and the Wasp: Quantumania.”

As potential viewers are inundated with an ever-growing number of options, studios have limited chances to build anticipation for their projects. At the same time, technological advances have made it easier than ever for products to stand out. “People want their film to have its own identity,” Rosen said in an interview at a Los Angeles coffee shop. “The genie’s out of the bottle as far as the limitless ability to customize something for your film. Clients, studios, agencies, whatever, they all know that and like to take advantage of it.”

Rosen spent his 20s playing guitar in the New Jersey band the Parlor Mob. After moving to LA in 2014, he got a job as the in-house composer at a trailer house — the specialized production companies behind these promos. Three years later, he co-founded Totem, a music library that creates custom tracks for trailers. Much of Rosen’s output is original compositions, but the ones that get the most attention are his overhauls.

“Almost never does a song just drop into a trailer and work,” he said. “Maybe it needs to feel more epic or more emotional, or maybe it needs to feel subtler with things pulled away.”

Trailerization is a relatively new term and the distinctions within it are malleable. There are reimaginations, which are usually instrumental covers by composers. There are overlays, where elements are added to a song in varying degrees. Then there are remixes, where the source material is distinctly altered, often to shift the context.

Some distinguish between remixes and overlays by what the composer has to play with. If there’s a full set of stems — the separated digital parts that comprise a song — it’s a remix. If stems aren’t available, it’s an overlay.

Occasionally composers will be asked to create “invisible overlays,” where they make adjustments that are imperceptible to most listeners but nudge a song toward a more wide-screen sound.

The trailerization process is now so common that even when a trailer uses the film’s original score, it too will be adjusted. “Trailers are a mini version of the movie,” said Cato, the one-named composer whose credits include performing a system update on Vangelis for the “Blade Runner 2049” trailer and giving Guns N’ Roses an anguished-turned-pulverizing remix for Jason Momoa’s Netflix revenge film “Sweet Girl.”

“You have to suck people into the theater and tell a story in 2 1/2 minutes,” Cato added. “That is so intense and builds so quickly that most music written for the actual movie will be way too long and drawn out.”

In the past, trailers often relied on the scores of previously released films, but that practice has basically become verboten. Starting in the late 1970s, composer John Beal pioneered original scores for trailers, but that required a recording studio full of musicians, making it a costly, resource-heavy endeavor. Today, with developments in software, it’s easier than ever to simulate those sounds.

“I could sit at my computer at home and you wouldn’t know that there wasn’t a 100-piece orchestra there,” Rosen said. “You couldn’t do that 10 years ago.”

MANY POINT TO the trailer for “The Social Network,” from 2010 — which featured a Belgian women’s choir singing Radiohead’s “Creep” — as the origin of what became the trailerization trend. Its success incited a deluge of trailers using slow and sad covers of well-known songs, usually featuring female vocalists. Recent examples include Liza Anne’s version of “Dreams” by the Cranberries for “Aftersun” and Bellsaint’s interpretation of R.E.M.’s “Losing My Religion” for the second season of the “Chucky” TV series.

Sanaz Lavaedian, the senior vice president of music for the trailer house Mocean, said that when she entered the industry in 2011, there was still a lot of resistance from artists who didn’t want their music used for commercial purposes. Covers provided a workaround. Now, as more musicians are struggling to make a living, they’re often more open to trailers not just using their music but modifying it.

“There were so many bands that didn’t think licensing was cool, so they never let us do it,” Lavaedian said. “Now they’re like, ‘Oh, we’re going to make half a million dollars on this? Never mind.’”

Many high profile trailerizations are applied to songs that are decades old: Remixes and overlays allow the trailers to tap into the nostalgia evoked by the original. “If we were able to remix an Elton John song or a Beatles song, these are iconic artists,” Lavaedian said. “The second you hear their voice, you know who it is, and there’s a lot of weight in that. More weight than if it were a cover.”

Composer Bryce Miller’s big breakthrough came in 2019 with the “Godzilla: King of the Monsters” trailer, which featured his custom orchestral rendition of “Somewhere Over the Rainbow” atop images of kaiju carnage. His subsequent credits include a modernization of Blondie’s “Heart of Glass” for “House of Gucci,” an orchestral blend of the Rolling Stones’ “Paint It Black” and the “Addams Family Theme” for “Wednesday” and a haunting overlay for Nirvana’s “Something in the Way” in “The Batman” trailer.

“As soon as I can get rid of dated-sounding guitars and drums, I can build a more contemporary production that is pulling from more pop music sounds,” Miller said. “Older recordings sonically are a little thin and lack the heft that so many contemporary songs have.”

Unique remixes began appearing in trailers going back to the mid-2010s, but it wasn’t until the one for Jordan Peele’s 2019 film “Us” that studios and audiences began to really take notice. In the fresh interpretation, with its piercing strings and moody atmospherics, a celebratory weed rap by the Oakland duo Luniz became deeply unsettling.

“Every once in a while we get one of those game-changer trailers,” Lavaedian said. The “Us” trailer “is taking a song and deconstructing it down to its bones and then constructing it again to do what that film needed it to do. It was kind of groundbreaking.”

MARK WOOLEN, THE founder of the trailer house Mark Woolen & Associates, specializes in award-season films and was responsible for that transformative “Social Network” trailer. New York magazine once called him “the uncontested auteur of the trailer era.”

In a phone interview, Woolen noted that in contemporary trailers, omniscient narration has largely disappeared (that means no more hackneyed “In a world …” setups) and there’s less dialogue from the film. Trailers “can be more impressionistic and elliptical in their storytelling,” he said. “It’s more about creating a feeling in a lot of the work.”

As a result, the trailer’s soundtrack has become increasingly crucial. “Music is sometimes 80 to 90% of the process to us,” Woolen said. “It’s trying to cast that right piece of music that’s going to inspire and dictate rhythm and set tone and inform character and story, and hopefully make an impression.”

For Amazon’s recent love triangle “My Policeman,” Woolen used Cat Power’s “Sea of Love,” which has become a romantic favorite among aging millennials. Though Cat Power’s original interpretation was stripped down to just singer Chan Marshall’s voice and strums on an autoharp, Woolen had a composer overlay swelling strings as the drama became more fraught.

Beyond providing the vibes, a song is often selected for a trailer because the lyrics convey the film’s narrative themes. Woolen didn’t just select “Sea of Love” because it is mysterious and seductive. He was equally guided by the refrain “I want to tell you how much I love you” and the ambiguousness of who that “you” might be.

In Marvel’s “The Ant-Man and the Wasp: Quantumania” trailer, as the heroes realize the size of the predicament they’ve gotten themselves into, the sound design emphasizes Elton John singing, “I should have stayed on the farm / I should have listened to my old man.”

Deciding which song a trailer uses and how it’s employed can involve studio marketing executives, the filmmakers, the team at the trailer house and the composer. A trailer’s creation can take years and is often covered by restrictive nondisclosure agreements, preventing the people behind it from discussing the details of making it, even after it has been released.

Because the material is so protected, the musicians rarely see the images that will be included in the trailer. Instead they have to rely on a music supervisor or creative director at a trailer house to guide them through inception and multiple rounds of revisions. “We’re literally dealing with billions of dollars in unreleased assets,” Lavaedian said of the footage from the films. “There’s no way we can send that to a composer.”

UNLESS YOU KNOW where to look on the internet, the pieces made by trailer composers are largely uncredited, and sometimes contractually so. Trailerizations are created “to live exclusively in the trailer,” Rosen said. “They serve as a piece of marketing.”

But that may be changing.

When the agency Trailer Park approached Miller about doing a trailerization for the first volume of the fourth season of “Stranger Things,” he was told the general plot and tone of the episodes. He’d long wanted to do something with Journey’s “Separate Ways (Worlds Apart)” and it turned out the song was on the agency’s shortlist as well.

After spending months on his ominous remix, it made it to the final stages of the approval process where the original musicians had to sign off. Steve Perry, the song’s singer, loved it and came to Miller’s studio to help construct an extended remix. Then he got Netflix to release both versions on the official soundtrack, with Miller’s name attached.

Miller called Perry inspiring and a joy to work with. “He’s also like a runaway train. As soon as we finished ‘Stranger Things,’ he’s like, ‘What are we doing next?’” The pair collaborated again on a trailerization of Journey’s “Any Way You Want It” for the Hulu series “Welcome to Chippendales.”

Where will trailerization at large head next? Recently, there’s been an interest in 1990s alternative rock hits, with remixes of Spacehog and the Toadies appearing in trailers for “Guardian of the Galaxy Volume 3” and “The Midnight Club.” In the promo for “Babylon,” the team of composers known as Superhuman created a Jazz Age-influenced interpretation of David Bowie’s “Fame” that’s almost as nutty as the film itself.

With decades of material to work with, Rosen hopes the trend continues. “There’s more opportunity for creativity from me and other people,” he said. “I view it as a new life for a lot of these artists’ songs.”

This article originally appeared in The New York Times.