Bohemian Rhapsody, a biopic about Queen's late frontman Freddie Mercury, is up for five awards. Two surviving band members will play at Sunday's ceremony, joined by Adam Lambert singing lead.
Some Hollywood luminaries have criticized truncating the broadcast of awards for best cinematography, film editing, live action short, and makeup and hairstyling. Some parts will be shown later.
The Academy of Motion Picture Arts and Sciences has dropped the widely criticized new award it introduced less than a month ago, saying the idea needs "further study."
After two years of #OscarsSoWhite hashtags, the Academy vowed to double the number of women and people of color by 2020. While it's close to achieving that, overall membership remains far from equal.
Despite a statutory rape conviction, Polanski has been nominated for three Academy Awards. He won the best director award in 2003 for his film The Pianist.
It may be Hollywood's biggest night, but fewer people chose to watch the 90th Academy Awards on Sunday. It's the fourth consecutive year viewership has declined as Oscars lose luster to Web rivals.