James Cameron tore into Screening Room at CinemaCon on Thursday, arguing that the start-up threatens the moviegoing experience, while pledging to continue to deliver epic films that compel people to go to cinemas.

“Together we’re going to continue to make this industry the biggest show on earth,” Cameron told a crowd of exhibitors. “It’s essential for movies to be offered exclusively in theaters on their initial release,” he added. “So boom.”

Cameron took the stage to vent his opposition to Screening Room at the end of 20th Century Fox’s theatrical film slate presentation in the Colosseum at Caesars Palace. He also used the occasion to announce that he will make four “Avatar” sequels instead of a planned three.

He praised theater owners for making investments to improve picture and sound quality, and thanked them for all they did to keep the cinema experience “sacred.” He added that moviemakers need to do their part to bolster the exhibition business.

“Our job as filmmakers is to keep making films that play best on that big screen,” said Cameron.

From television to the advent of video, Cameron said, “There has always been some threat” to moviegoing. But he said that the business has “always answered that threat in the same way. By being great and showmanship. And by creating something in a movie theater that you can’t get anywhere else.”

Screening Room has been a topic of much debate at this year’s CinemaCon. The company wants to offer films in the home the same day that they hit theaters. It plans to charge roughly $150 for access to a set-top box that transmits the movies and charge a $50 rental fee. Consumers have a 48-hour window to view the film.

Screening Room is backed by Sean Parker, an entrepreneur known for his work with Facebook, Napster and Spotify. Prem Akkaraju, a former music industry executive, is its co-founder and CEO.

Many theater owners remain fiercely opposed to the proposal and “Hangover” director Todd Phillips also criticized the start-up at CinemaCon this week. However, Screening Room has lined up supporters such as Steven Spielberg, Peter Jackson and Martin Scorsese. No major studios have endorsed the company, but AMC Entertainment, the country’s second biggest exhibitor, has signed a letter of intent.