'La La Land' and 'Hacksaw Ridge' editors reveal movie-making secrets

Tom Cross and John Gilbert dish on the editing process.

— -- During movie awards season, a lot of attention is given to the Oscar-nominated actors and directors.

But what about the nominees whose job responsibilities aren't quite so clear to the average movie-goer?

For a new series called "Behind the Lens," ABC News got to know the people who were recognized for work behind the camera.

Tom Cross first met Damien Chazelle a few years ago, when he was asked to edit a short version of his first major film, "Whiplash," to attract financing.

So, when Chazelle was looking for someone to edit "La La Land," Cross was an obvious choice.

"The thing that struck me was it was so dreamy and very hopeful and very earnest, whereas 'Whiplash' was more about the suspense and tension. 'Whiplash' was trying to use film editing to achieve a certain brutality, and in 'La La Land,' it was apparent he was going or something very, very different. I was very excited by it," Cross told ABC News. "This was much more ambitious."

Chazelle told Cross that he wanted the movie to feel "naturalistic," while at the same time creating "dreamy moments that would serve as an expression of what's in the hearts of the characters." To do so, Cross worked closely with the cinematographer, who chose the equipment used to shoot the film, to make sure that the overall feel of the movie was what Chazelle wanted. He also used old-time techniques to give the modern-day movie a more classic feel.

"[Chazelle] really wanted to tell the story with, as he called it, 'the language of dreams.' So he wanted to use techniques from classic Hollywood cinema -- a lot of montages, a lot of irises, a lot of fade in, fade out -- and tell the story with mostly just pictures," he explained. "The biggest thing was, he didn't want the movie to have just one rhythm. He wanted it to have the different rhythms of romance."

That type of specificity took time. According to Cross, unlike the edit of "Whiplash," which he only had a few months to complete, putting together "La La Land" took the better part of a year. A lot of those changes involved composer Justin Hurwitz, as Chazelle wanted certain moments of the score to match up with edits.

"It’s natural for the needs of the movie to evolve in the editing room, and even the most planned-out sequences end up changing. But Damien wanted to go for the same level of precision," he said. "I had to adjust the picture and it was all about perfecting where certain dissolves would hit the music and we kept working on that even through the final sound mix. When we were on the mixing stage, we would vet every single big downbeat of the music to see if it hits right on the picture and if it didn't, we would make the change."

Given all the work that went into making "La La Land," Cross is thrilled that it received a record-tying 14 Oscar nominations.

"In order for Damien to pull off this ambitious vision, he knew he it was going to require all departments firing on all cylinders, so I'm really happy that the departments I worked most closely with -- sound mixing and sound editing -- were recognized, but I also feel it's very validating that the other departments are recognized as well," he said. "This was truly a team effort."

"Hacksaw Ridge" editor John Gilbert feels similarly about the six nominations his film received. However, the editing process was very different from the Cross described. For more about that process, including the moment director Mel Gibson provided sound for the movie in a most unlikely way, watch the video above.