You would think doubling a film's chances for an Academy Award nomination would thrill everyone in Hollywood, where an Oscar is the highest form of ego-stroking in a town of big egos.

Yet attitudes among stars, filmmakers and executives range from cautious optimism to harsh disagreement over the big change at next March's Oscars - 10 best-picture nominees instead of the usual five.

The Academy of Motion Picture Arts and Sciences is experimenting with the expanded slate as Oscar organisers hope to spark more interest in the awards show and spread the prestige around to different kinds of films.

It's not without precedent.

From 1931 to 1943, the academy generally had 10 best-picture contenders, and as many as 12 some years.

Since then, though, it's been only five.

Many in Hollywood wonder if doubling the field will cheapen the honour of scoring a nod for the biggest prize in show business.

"I think it's terrible. My knee-jerk reaction is that it's a really bad idea. We'll see, but I think 10 just dilutes it too much," said Matt Damon, an Oscar winner for the Good Will Hunting screenplay he wrote with good mate Ben Affleck.

The Toronto, Venice and Telluride fests traditionally mark the start of awards season, as studios begin trotting out their big guns for the Oscars.

Such recent festival premieres as Crash, No Country for Old Men and Slumdog Millionaire have gone on to win best picture.

"Generally, the five films that get nominated, people will make time to see those movies," said Damon, who stars in Steven Soderbergh's Toronto International Film Festival entry, The Informant!.

"Whereas 10, it just seems like, what aren't they nominating?

"I hope it doesn't devalue the nomination because to be nominated for best film is obviously an incredible honour," said Peter Jackson, whose The Lord of the Rings: The Return of the King swept the 2003 Oscars.

"If it's the same honour with double the number of nominees, I'm not sure. I don't know. I guess time will tell."

Academy officials say they would not mind seeing the occasional documentary or foreign-language film score a best-picture nomination.

But the switch to 10 nominees mainly springs from Oscar planners' efforts to popularise the show amid generally declining TV ratings over the last 25 years, as smaller, sober dramas have come to dominate instead of big studio productions.

Lighter films occasionally sneak in - the road-trip romp Little Miss Sunshine or the pregnancy comedy Juno.

Yet the best-picture lineup most often fills up with broody films such as last year's The Reader, Frost/Nixon and Milk - critical but not commercial triumphs.

"It used to be actually that very big box-office movies tended to be the ones that win," said Chris Weitz, director of vampire sequel The Twilight Saga: New Moon and a 2002 Oscar nominee for the About a Boy screenplay.

"Studios are now spending money on things they see as giant blockbusters rather than necessarily spending a lot of money on big historical epics that might do well at the Oscars."

The best ratings in recent times have come when huge hits such as Titanic or The Return of The King won best picture.

With 10 nominees last year, the acclaimed Batman blockbuster The Dark Knight probably would have been in the running, potentially giving general movie-goers more reason to watch the film.

"We're trying to do something that will make the award no different than it is now, but give people the chance to somehow be involved more in the awards," said academy president, Tom Sherak.

"We said, 'wouldn't it be great if by doing this, a comedy got nominated? Wouldn't it be great if a populist movie got nominated?"'

That idea could also backfire if Oscar voters nominate 10 sober little dramas instead of five, giving audiences at home no more reason to watch.

Oscar attention often translates to better box office and DVD sales, so distributors of those sober little dramas don't mind the expanded best-picture category.

Michael Barker, co-president of Sony Pictures Classics, said that if there had been 10 nominees last year, the company's critical darlings Rachel Getting Married and Frozen River might have made the cut, potentially broadening their audience.

"The more films that are going to be seen by more people the better," Barker said.

"It gives more shots for my pictures to get in there.

"It might double the chance for high-quality films to get in."

Most in Hollywood have a wait-and-see attitude about the best-picture change, and Sherak said if 10 nominees don't work, the academy can always switch back to five.

"If I have the amazing fortune to be nominated, then I think it's a good idea," joked Jason Reitman, who directed George Clooney in Up in the Air, the filmmaker's follow-up to his 2007 best-picture nominee Juno.

The success of the academy's experiment depends on what movies actually get nominated, Reitman said.

If a film that's "wonderful but goes unseen" finds a wider audience because of a best-picture spot, the change will be worthwhile, Reitman said.

Not so "if 'Saw VI' takes the 10th spot", he said.

For this year at least, awards watchers will have to extend their list of candidates to include more films - perhaps even audience favourites like the animated comedy Up or the sci-fi tale Star Trek.

"The thing that could be very, very, very exciting is if it breaks the kind of lethargy that's easy to fall into with the academy, when you have the same five or six films that are mentioned at these times," said Quentin Tarantino, an Oscar winner for his Pulp Fiction screenplay and whose World War II saga Inglourious Basterds is up for awards consideration this year.

"You kind of know it's usually between two of the five.

"There's rarely a ringer. There's rarely a Juno in there. It usually is these good, serious movies battling it out in the serious movie competition, as opposed to the movies-for-all competition."