Dark comedy "Birdman" triumphed Saturday at the Independent Spirit awards show, in its latest success on the eve of the all-important Academy Awards.

The movie, about a washed-up superhero actor battling to revive his career on the stage, took the best film prize as well as best actor for Michael Keaton.

Best director went to Richard Linklater for coming-of-age drama "Boyhood," which is running neck-and-neck with "Birdman" for Best Picture at the Oscars, the climax of Hollywood's annual awards season on Sunday.

Best actress at the Spirits went to Julianne Moore, who is also tipped to win the category at the Oscars for playing a professor suffering early-onset Alzheimer's in "Still Alice."

J.K. Simmons won best supporting actor as sadistic jazz teacher in Damien Chazelle's "Whiplash," while the best supporting actress winner was Patricia Arquette, as the mother in "Boyhood."

Both Simmons and Arquette are seen as frontrunners in the same categories at the 87th Oscars show, which takes place Sunday evening at the Dolby Theatre in downtown Hollywood.

"Birdman" has swept a string of prizes ahead of the Oscars including top prizes from the Screen Actors Guild and the Directors Guild of America.

But Linklater's "Boyhood" -- which was made over 12 years with the same actors aging with their characters -- scooped up the biggest awards at last month's Golden Globes, as well as Britain's BAFTAs.