By MICHAEL CIEPLY

LOS ANGELES - Movie stars, who not so long ago vied to make $20 million or even $25 million a picture, have seen their upfront salaries shrink in the last several years as DVD sales fell, stardriven vehicles stumbled at the box office and studios grew increasingly stingy.

Most of the three dozen or so topbilled actors in the 10 films who were up for best picture in the Academy Awards ceremony, including blockbusters like “Up” and “Avatar,” appear to have received relatively minuscule upfront payments for their work.

When the estimated salaries of all 10 of the top acting nominees are combined, the total is only a little larger than the $20 million that went to Julia Roberts for her appearance in “Erin Brockovich,” a best-picture nominee in 2001, or to Russell Crowe for “Master and Commander,” a 2004 nominee .

Peter Dekom, a film industry lawyer who co-wrote the book “Not on My Watch: Hollywood vs. the Future,” pegged the devaluation of movie stars to a lack of interest among younger viewers.

“Stars don’t resonate with the ‘what’s next’ ” crowd, theorized Mr. Dekom. “They attract an over-30 audience, which is going to the movies less in an impaired economy.”

Specific salaries and deal terms are notoriously difficult to pin down. (The estimates are based on interviews with a dozen producers, agents and executives who were briefed on the various deals but spoke on condition of anonymity to avoid conflict with the actors and companies involved.)

Paramount’s “Up in the Air” was made for about $25 million. It was possible only because George Clooney, according to people briefed on the film’s finances but speaking anonymously to avoid conflict with the star or Paramount, took an initial fee that was roughly a tenth of the $20 million that Leonardo DiCaprio, a frequent Oscar contender, has received in the past.

Once , the biggest stars were rewarded with deals that paid them a percentage of so-called first-dollar gross receipts; that is, they began sharing in the profits from the first ticket sale, not waiting until the studio turned a profit. Now studios often insist that even top stars forgo large advance payments in return for a share of the profits after a studio has recouped its investment.

Such deals can be extremely lucrative when they give stars a substantial share in home-video revenue. So Sandra Bullock, who won the Academy Award for best actress, cut her usual $10 million fee to $5 million for “The Blind Side.”But she will make $20 million or more from the movie because it was a hit. Mr. Clooney similarly stands to make additional millions when all the revenue from “Up in the Air” is finally counted.

A rare star, in rare circumstances, can still command the kind of deal that was more prevalent five years ago. Angelina Jolie, for instance, still receives $20 million for appearing in an action film like “Salt,” set for release in July by Columbia Pictures, according to two people who were briefed on her deal.

In this year’s best-picture roster, the star that attracted the largest upfront fee appears to be Brad Pitt, for his work in “Inglourious Basterds.” People briefed on that film’s finances put his initial payment at $10 million, with more to come from profit participation .

But Mr. Pitt’s co-stars and the stars of pictures as impressive as “The Hurt Locker,” or “Precious: Based on the Novel ‘Push’ by Sapphire,” often worked at or near guild minimums.

For the most part guild minimums are set in a provision of the Screen Actors Guild contract that Hollywood cognoscenti refer to as Schedule F. It requires that an actor receive at least $65,000 for work in a feature film.

The pay for a number of actors in “District 9,” “A Serious Man” and “An Education” was at or close to guild minimums, as each was made on a relatively low budget. As for the ultrahigh-budget “Avatar,” the highest paid appears to have been Sigourney Weaver, though she almost certainly worked for a small fraction of the $11 million she was reported to have been paid for “Alien: Resurrection” in 1997.

Zoe Saldana and Sam Worthington, meanwhile, got fees that were more than guild minimums but less than enough to make them feel financially secure, despite having acted in a picture with over $2.5 billion in ticket sales around the world.

“Every actor fears unemployment,” Mr. Worthington said in a January interview with The Herald Sun in Australia.