No Academy group has tinkered more with its rules than the music branch. Over the years, categories have been added and subtracted, and the award titles have changed repeatedly. Even the idea of what is eligible and what is not — for songs and scores alike — has been overhauled numerous times.

The thorniest issue facing the music branch each year involves what to disqualify, and why. In an era of sequels, franchises and other films in which pre-existing music is involved, the question of originality arises constantly, according to members of the branch executive committee that makes those rulings.

Only original scores are considered by the Academy, the key rule-book definitions being “substantial body of music … written specifically for the motion picture”; “scores diluted by the use of tracked themes or other pre-existing music … shall not be eligible.”

But for most of its existence, the Academy also — in a separate category — honored composers who adapted the work of others into dramatically effective scores. John Williams’ first Oscar was for adapting the songs of “Fiddler on the Roof.” Marvin Hamlisch won for interpreting Scott Joplin rags for “The Sting.” Nelson Riddle won for arranging 1920s songs for “The Great Gatsby.” Leonard Rosenman won twice, for adapting classical music in “Barry Lyndon” and Woody Guthrie tunes in “Bound for Glory.”

In most years, this category combined musical scores (five or more new songs) with adaptation scores. The category was abolished after 1983. Alex North’s clever use of Italian opera in “Prizzi’s Honor” and Craig Armstrong’s production of dozens of songs in “Moulin Rouge” were ineligible for Oscar, for example, because a category to fit their accomplishments no longer existed.

In recent years there have been a growing number of calls to reinstate the category. This year alone, Clint Mansell’s use of Tchaikovsky in “Black Swan” and Carter Burwell’s use of 19th-century hymns in “True Grit” have been much discussed. If the term “adaptation score” was added to the “original musical” category — the latter of which exists for song scores but is rarely activated due to too few entries — wouldn’t the decision-making process be easier?

“I don’t think so,” says branch exec committee chairman Bruce Broughton, citing pressure to reduce, not expand, the number of awards being given. “If we had five real song scores, we could consider activating that. But adaptation? I would say that one is gone.”

Robert Kraft, president of Fox Music, supports the idea of reinstating the adaptation category. “In a postmodern world where remixing, mashups and sampling are an accepted aspect of contemporary work, we need to acknowledge the efforts of composers who experiment in this arena,” he says.

Not everyone is convinced, however.

Asks another studio music exec: “Are there enough worthy projects that would qualify for that category? Or would we be even more outraged that unworthy people are taking home our industry’s most prestigious award because it’s not a real competition in yet another category?”

A busy Oscar consultant, who also preferred anonymity because of awards-season sensitivity, admits being conflicted. “Original use of published music is still a creative endeavor. It’s not exactly original music, it’s adapted, so why not create an adapted-score category?” he says.

“On the other hand, take existing great material you know everyone loves, like the Pachelbel Canon in ‘Ordinary People,’ and voters might vote for what they like as opposed to the actual transformation of that original material. ‘Across the Universe’ would have won hands down just because it was the Beatles and for no other reason of merit.”

But that argument can be made about almost any category. Voters have their own standards, and music is a very subjective arena, even among working composers. (The Beatles, in fact, won the “original song score” Oscar for 1970’s “Let It Be” despite the fact that it was a documentary about the making of an album, not a movie for which they wrote original songs.)

Hamlisch, who won that 1973 music-adaptation Oscar for “The Sting,” thinks the category is still a valid one. “It is an art form,” he says. “It’s not just taking some stuff and slapping it together. When done correctly, it can be very artistic and important to the film. You have an element that people know,” he adds, “but you’re going to surprise them with how it is used in a totally different way.”

But, he acknowledges, there need to be enough such scores to merit an award. “Let’s say there were only two for the year. It becomes an instantaneous nomination, and I think that’s what they were trying to avoid when they abolished (the category). The way to go about this is to see whether everyone can agree on a number that makes it a contest, and not just a prize you give out. It’s an important art form, and I don’t think that it should be belittled. But it shouldn’t be automatic.”

Get more from Eye on the Oscars: Music:
Music branch can’t please all the people | Song category hangs by thread | Daft Punk immersed in ‘Tron’ | Songs in contention
Michael Brook | Carter Burwell | Danny Elfman | Grizzly Bear | Jan Kaczmarek | Rachel Portman | Anton Sanko