How does Oscars voting work? This is how winners are decided

The road to an Oscar winds through a long awards season, which finally culminates at the Academy Awards.

Christopher Nolan's Oppenheimer is leading the pack ahead of the 96th ceremony, with 13 nods, but other major contenders include Barbie, Killers of the Flower Moon and Poor Things.

The award nominations caused controversy after Ryan Gosling was nominated for best supporting actor for his role as Ken in Barbie but its director Greta Gerwig and lead actor Margot Robbie were snubbed.

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So how are the winners decided? Here's how the voting process works.

Who votes on the Oscars?

The Academy of Motion Picture Arts and Sciences boasts some 10,000-plus members, divided among 17 branches.

All academy members have to be involved in the movie business in some capacity, but membership isn't restricted to creatives — there are branches for executives and marketing and public relations professionals, as well.

While nominations are mostly decided by members of the relevant branch (directors nominate directors, for instance), all voting members can nominate films for best picture.

Once nominees are decided, all voting members are eligible to cast their ballots in any category.

In recent years, the academy has taken steps to diversify its membership, especially after receiving criticism for a spate of all-white acting nominees.

It adds new members once a year.

When does Oscar voting take place?

Voting takes place over a few days not too long before the ceremony.

How are votes cast?

While the final results can sometimes be controversial, there's no risk of hanging chads — voting takes place entirely online.

Tabulation for most categories is simple — the nominee that gets the most votes wins.

Best picture, on the other hand, employs ranked-choice voting (also known as preferential voting).

Voters order the nominees by preference; if one movie comes away with more than 50 per cent of the first-place votes in the first round, that's the winner.

But if no movie meets that threshold, then the one with the fewest first-place votes is eliminated — people who had ranked that film first will have their votes transferred to their second choices.

And so on it goes until some movie wins a majority.

It sounds complicated, we know, but proponents of ranked-choice voting argue that it's more representative, especially in a large field of nominees.

Who knows the winners before they're announced?

According to the academy website, just two PricewaterhouseCoopers partners know the results beforehand.

PwC is the accounting firm that tabulates the votes.

Each partner is stationed in the Dolby Theatre's wings during the ceremony with a full set of winners' envelopes.

They're charged with handing the sealed envelope to the winner.

Infamously, in 2017, a PwC accountant handed Warren Beaty and Faye Dunaway the wrong envelope, resulting in the "La La Land"/"Moonlight" best picture fiasco.