Fifty or 60 years ago, it was not unusual to see the name of the composer right up next to that of the producer or director in a movie’s opening credits — Max Steiner on “Casablanca,” for example, or Erich Wolfgang Korngold on “Kings Row.”

Those prestige spots reflected the value filmmakers placed on music in that era. The contributions good music can make to a film — from eliciting an emotional response from the audience to helping add atmosphere, establish setting or pace the drama — were seen as critical to the process.

Producers sometimes hired a composer to enhance the prestige factor of a movie — Leonard Bernstein for “On the Waterfront,” Aaron Copland for “The Red Pony,” even Isaac Hayes for “Shaft.” But nowadays, such a notion seems positively quaint.

One major Hollywood filmmaker recently showed up at a composer’s studio to preview the music (based on synthesizer mockups of what was to eventually be recorded by an orchestra), listened for a few seconds and declared, “Hate it! What else ya got?”

James Horner, a double Oscar winner for “Titanic” and composer on this year’s “Avatar,” says that a decade or more ago, “the composer was always at least equal in rank to picture editor.” Now, he thinks, music “has slipped closer to the level of sound effects” for many of the directors with whom he’s worked.

“Avatar” is a rare exception to the rule. Horner worked exclusively on James Cameron’s 3D extravaganza for more than a year. Many of his sought-after colleagues, especially those with long histories with directors, get better-than-average treatment. John Williams has already begun writing music for Steven Spielberg’s “The Adventures of Tintin,” even though the film won’t be out for two more years.

But for the average composer, it’s a different story.

Fees are declining, schedules shrinking, credits are buried — three reasons that there is a movement now to unionize composers for the first time since the Composers & Lyricists Guild of America failed back in the 1970s, the result of the studios’ refusal to negotiate music-ownership rights.

Technology is partly to blame, says Emmy-winning composer Richard Bellis, author of “The Emerging Film Composer” and leader of ASCAP’s annual film-scoring workshop. Twenty or 30 years ago, he says, “the person who composed the music had to be knowledgeable about live scoring, had to be able to write music, conduct music, create music from whole cloth rather than ‘selecting’ music,” as often happens today with the availability of such tools as Band-in-a-Box, Cinescore or generic library music.

“Today’s filmmaker is more inclined to think ‘I need a composer because I’m just too busy to do it myself’ and there are literally hundreds of kids out there who will do it for next to nothing,” Bellis says.

What they’re missing, say many on the music side of the biz, are the dramatic instincts and creative spark of the trained, experienced composer. Agent Richard Kraft, who represented film-scoring giants Jerry Goldsmith and Elmer Bernstein, says, “We are in a period where the thought that film music is an artistic expression is at an all-time low.”

No one is immune to the cavalier treatment of music. In recent weeks, leading American classical composer John Corigliano (an Oscar winner for “The Red Violin”) had his music for “Edge of Darkness” tossed out, and Danny Elfman’s reportedly lush, moody music for “The Wolfman” was dumped.

Rejected scores are nothing new. Alex North wrote music for “2001: A Space Odyssey” that Stanley Kubrick hated, preferring classical music from his record collection. Goldsmith’s lavish, orchestral and choral score for “Legend” was replaced by a rock-tinged, electronic effort by technopop group Tangerine Dream. Even England’s William Walton wasn’t immune, losing nearly all of his “Battle of Britain” score because of studio politics in 1969.

Most of the time, say music insiders, scores are tossed because the film isn’t working and, beyond the usual recutting, there’s little else left to try during the final weeks of post-production. Music becomes an easy, and increasingly common, scapegoat. Goldsmith’s “Chinatown” was a rare instance of a last-minute replacement score that wound up with an Oscar nomination and became a classic.

When, in 1960, Alfred Hitchcock asked Bernard Herrmann what he thought the music for “Psycho” should be, Herrmann came up with a unique all-strings ensemble (“a black-and-white sound,” he said, to complement the black-and-white cinematography), a wildly original approach that helped to define the film and make it a success.

“That’s about artistic choices,” Kraft says. Today, he adds, “Psycho” would be “temped” (prescored with temporary music consisting of pre-existing cues that the editor likes), thus setting the style, direction and amount of music even before the composer is hired.

Adds Horner: “No one just says, ‘What do you think of my picture? I want you to write what’s in your heart.’ I haven’t heard that in years. That simple concept does not exist anymore.”