Catholic Church abuse movie Spotlight was named best picture, the top award at Sunday's Oscars ceremony, after a night peppered with pointed punchlines from host Chris Rock about the #OscarsSoWhite controversy that has dominated the industry.

In a ceremony where no single movie commanded attention, Mexico's Alejandro Inarritu nabbed the best directing Oscar for The Revenant, becoming the first filmmaker in more than 60 years to win back-to-back Academy Awards. Inarritu won in 2015 for "Birdman."

The Revenant went into Sunday's ceremony with a leading 12 nominations, and was among four movies believed to have the best chances for best picture after it won Golden Globe and BAFTA trophies.

The ambitious 20th Century Fox Pioneer-era tale, shot in sub-zero temperatures, also brought a first Oscar win for its star Leonardo DiCaprio, who got a standing ovation from the A-list Hollywood audience.

"I do not take tonight for granted," DiCaprio said, taking the opportunity in his acceptance speech to urge action on climate change.

Yet voters in the Academy of Motion Picture Arts and Sciences chose Open Road Films' Spotlight, which traces the Boston Globe's 2003 Pulitzer Prize winning investigation of child sex abuse by Catholic priests, for best picture. The movie also won best original screenplay.

"This film gave a voice to survivors, and this Oscar amplifies that voice, which we hope can become a choir that will resonate all the way to the Vatican," said producer Michael Sugar.

Rising star Brie Larson, 26, took home the statuette for best actress for her role as an abducted young woman in indie movie Room, adding to her armful of trophies from other award shows.

"Jabbing at Hollywood"

Racial themes and barbs about the selection of an all-white acting nominee line-up for a second year were a running theme of the show, dubbed "the white People's Choice awards" by Rock, an outspoken black comedian.

He questioned why the furore over diversity in the industry had taken root this year, rather than in the 1950s or 1960s, saying that black Americans had "real things to protest at the time".

"We were too busy being raped and lynched to care about who won best cinematographer," Rock added. In a taped section, Rock visited the Los Angeles neighbourhood of Compton – the heart of the hip-hop music industry – to ask residents if they had heard or seen the Oscar-nominated movies. None had.

Several nominees gave Rock a thumbs-up for striking the right balance on a tricky theme.

"I thought it was jabbing at Hollywood, yet at the same time even-handed, and kind of dealing with a new era of how we discuss diversity," said Adam McKay, director and co-writer of best picture nominee The Big Short. "Really impressive and really funny."

Rock wasn't alone in putting people of colour in the spotlight on the movie industry's biggest night.

"I (am) very lucky to be here tonight, but unfortunately many others haven't had the same luck," Inarritu said, expressing the hope that, in the future, skin colour would become as irrelevant as the length of one's hair.

Among surprises, Britain's Mark Rylance beat presumed favourite and Creed actor Sylvester Stallone to win the Academy Award for best supporting actor for Bridge of Spies.

"Sly, no matter what they say, remember, to me you are the best, you were the winner. I'm proud of you," Arnold Schwarzenegger, a fellow action star, said in a short video he posted online.

British singer Sam Smith's theme song for James Bond movie "Spectre" beat Lady Gaga's sexual assault awareness ballad Till It Happens to You.

Swedish actress Alicia Vikander won the supporting actress Oscar for transgender movie The Danish Girl while documentary Amy, about the late and troubled British pop star Amy Winehouse was also a winner.

Warner Bros' Mad Max: Fury Road was the biggest winner, clinching six Oscars, but all were in technical categories such as costume, make-up and editing.