86 on Sunday and would be the oldest acting winner ever.
The top prize winner at last year's Cannes Film Festival, Amour follows the agonizing story of an elderly man (Jean-Louis Trintignant) tending his wife (Riva) as she declines from age and illness.
Haneke thanked his own wife for supporting him in his work for 30 years.
"You are the center of my life," Haneke said.
The Scottish adventure Brave, from Disney's Pixar Animation unit, was named best animated feature. Pixar films have won seven of the 12 Oscars since the category was added.
The story of an dauntless princess (voiced by Kelly Macdonald) who balks at her parents' attempts to marry her off, Brave won out over a strong field that included Disney's Wreck-It Ralph and Frankenweenie.
"I just happen to be wearing the kilt," said "Brave" co-director Mark Andrews, who took the stage in his trademark Scottish garment.
The upbeat musical portrait "Searching for Sugar Man" took the documentary feature prize over a lineup of sober films that included the AIDS chronicle "How to Survive a Plague," the military-rape critique "The Invisible War" and the Israel-Palestine studies "5 Broken Cameras" and "The Gatekeepers."
Searching for Sugar Man follows the quest of two South African fans to discover the fate of acclaimed but obscure singer-songwriter Sixto Rodriguez, who dropped out of sight after two albums in the 1970s and was rumored to have died a bitter death.
"Thanks to one of the greatest singers ever, Rodriguez," said "Sugar Man" director Malik Bendjelloul.
There was a rare tie in one category, with the Osama bin Laden thriller Zero Dark Thirty and the James Bond tale Skyfall each winning for sound editing.
Oscar host Seth MacFarlane opened with a mildly edgy monologue that offered the usual polite jabs at the academy, the stars and the industry. He took a poke at academy voters over the snub of Ben Affleck, who missed out on a directing nomination for best-picture favorite "Argo," a thriller about the CIA's plot to rescue six Americans during the Iranian hostage crisis.
"The story was so top secret that the film's director is unknown to the academy," MacFarlane said. "They