A $300 million show business antitrust suit that is approaching trial in U.S. District Court in New York City pits some of the top movie and television composers against the major movie production companies and two television networks.

The plaintiffs, who include Elmer Bernstein, Marvin Hamlisch, Henry Mancini, Nelson Riddle, Alan Bergaman and David Rose, charge the companies with monopolizing the TV and movie music business.

At stake are untold millions of dollars in revenues now collected by the defendants because they control the copyrights to the music. The composers want ownership of the copyrights, as well as the performance fees that are collected by the companies everytime a song is played on the radio, TV, in nightclubs, at concerts - virtually anywhere.

In Feb. 1977, NBC made a separate settlement with the composer, giving them control over the copyrights. NBC also agreed to pay the composers' legal fees, amounting to $71,000.

The plaintiff claim that the defendants have conspired to deprive them of the copyrights to music and lyrics written by them for motion pictures and television shows produced by the defendants. The plaintiffs also allege that the defendants have monopolized the U.S. market for the publication of movie and TV music and lyrics.

Legal experts say this could be the biggest private antitrust suit ever to go to trial. Appropriately both sides have hired some of the most glittering legal talent available.

The plaintiffs number between 400 and 900 and are members of the Composers and Lyricists Guild of American. Plaintiff Berstein is president of CLGA, which is represented Theore Kheel, the noted New York labor negotiator. Louis Nizer is the lead attorney for the defendants.

Back in 1972, when the case was first file, Cyrus Vance, now Secretary of State, represented Universal; his former law firm is proceeding with the case.

In addition to Universal, the defendants include Twentieth Century Fox, Paramount, MGM, Warner Bros., Columbia Pictures, Walt Disney Productions, United Artists, CBS and the American Broadcasting Companies.

Currently, Judge Charles L. Brieant is deciding whether there should be a jury trial. At a hearing last week on the question, Nizer argued, "The complexities of this case are such that it is not properly triable before a jury."

He estimated that the case would take at least four months to try. Nizer argued that it would be difficult for a jury to sustain interest for that length of time.

Kheel, arguing for a jury, countered that it would take only a matter of weeks to prove that his clients are independent contractors. "The basic question (in this case) is whether the plaintiffs are employes and if that will take four months, I'll eat the National Labor Relations Act with all its amendments, Kheel said.

Noting the show business patina to the suit, Judge Brieant reacted to the Kheel statement by suggesting he might sell tickets for such an event.