Tony Angellotti distinctly remembers when he knew “Green Book” might go all the way.

The public relations executive and awards consultant was at the first public screening of the movie at the Toronto International Film Festival last year, when the audience began to react, even before the movie ended. “Explosive is how you’d characterize it,” he recalled in a recent email. “Tears, howls of laughter, spontaneous applause and a prolonged standing ovation.”

Universal, “Green Book’s” parent studio, had for months been assuming that the Ryan Gosling space ad­ven­ture “First Man” would be their best Oscar bet. But, Angellotti noted, Toronto upended that calculation and made “Green Book” a contender “right there and then.”

The Toronto International Film Festival — or TIFF, as its fans lovingly call it — was founded 43 years ago with no dis­cern­ible ambitions to be a Hollywood kingmaker. Known as a “best of the rest” festival, the week-long program focused mostly on movies that had premiered elsewhere, giving local Canadian audiences a chance to catch up with what the rest of the world was watching.

Nearly half a century later, TIFF is still a great catchall for films that have shown at Sundance, Berlin and Cannes. But it has expanded — both in time frame and curation — to become whatever its 400,000-plus attendees need it to be, depending on their tastes and tasks at hand.

TIFF, which this year will show more than 300 movies during its run of 11 days, is as valuable to programmers of arcane, experimental work as it is to theater owners looking for straight-up crowd-pleasers. It has become a popular destination for studios staging publicity junkets, as well as a gathering place for high-minded cineastes who wouldn’t think about anything as grubby as marketing.

Agents, producers and distributors still converge on TIFF to wheel and deal, even if in recent years the market has calmed somewhat. But the festival is just as useful to local filmgoers and cinetourists whose only goal is to see some good movies before they hit theaters (and maybe catch a director answering questions or glimpse a celebrity on the red carpet).

Amid the swirl of agendas, though, one has taken on particular prominence. Thanks to an audience award determined by the votes cast at each of its screenings, TIFF is becoming a modestly reliable Oscar predictor. And in casting those votes, it’s the garden-variety filmgoers — not critics, industry insiders or juries of film snobs — who have begun to wield the most power.

“Green Book” is just the most recent example. Since 2008, four winners of the Grolsch People’s Choice Award have gone on to win best picture, including “Slumdog Millionaire,” “The King’s Speech” and “12 Years a Slave.” All but one audience award winner, the Lebanese film “Where Do We Go Now?,” have been best-picture nominees. That track record has coincided with increasingly expensive awards-oriented marketing campaigns, as well as a burgeoning cottage industry in awards prognostication, both in traditional media and on Oscar blogs. The result is that TIFF has become ground zero in establishing consensus, not just about who will win reputation-burnishing (and box office-plumping) awards, but who will be able to compete in the first place.

Producer Michael Sugar, who will bring “The Report” and “The Laundromat” to Toronto this year, remembers when “Spotlight” played at TIFF in 2015. Although the film had premiered in Venice, it was during its first public screening in Toronto that Sugar thought he might have an awards movie on his hands.

“I never saw ‘Spotlight’ as an Oscar winner until that night,” he says, adding that it wasn’t just spectators tipping the scales, but also critics who “anointed it as an immediate front-runner.” (The audience award that year went to the psychological thriller “Room,” for which lead actress Brie Larson would win an Oscar.)

But as suddenly as momentum can get started at TIFF, it can also stall. By the time “A Star Is Born” arrived at the festival last year, it had already been the subject of a hype-y whisper campaign on the part of celebrities such as Sean Penn, and had made a splashy, Old Hollywood-style debut at Venice. Instead of leaving Canada as the front-runner many had presumed it to be, “A Star Is Born” had stiff competition from the wildly popular “Green Book” as well as the critical favorite “Roma,” by Alfonso Cuarón.

Toronto isn’t the only stop for movies hoping to benefit from the awareness and prestige an awards campaign can bring. Often those films will play festivals in Venice and/or Telluride, Colo., first. But both are relatively rarefied compared with TIFF, which is far more logistically accessible and has become an undeniable bellwether. (Sensitive to being scooped by Telluride, TIFF announced in 2014 that movies could only premiere in Toronto during the highly coveted first weekend if they had not already screened in North America; they eased the policy the following year.)

Producers Gigi Pritzker and Rachel Shane will bring the period drama “Motherless Brooklyn” to Toronto as part of a festival strategy that will capitalize on the film being Edward Norton’s directorial debut, its literary pedigree and its thematic grounding in New York history (it will be the closing night film at the New York Film Festival).

Whether “Motherless Brooklyn” wins the audience award or not, Pritzker adds, she welcomes its role in shaping a film’s fortunes. “We’re now in a world where there really aren’t gatekeepers as much as there used to be,” she notes. “People can source opinions directly and so many things are disaggregated. So it makes total sense that the audience awards would start to gain more power.”

For his part, Sugar is quick to remind filmmakers and fans alike that for midrange, adult-oriented movies to keep their place in the cinematic ecosystem, the people who finance them need to be made whole — and while awards can help with that, they shouldn’t be mistaken for anything other than a means to an end. The most important upshot of “Spotlight” becoming a contender at Toronto, he says, was that it convinced the distributor there was an audience for the film outside small art houses, and thus they spent more money on promotion and publicity.

“We don’t set out to make movies to get awards,” he says. “We always approach [these conversations] through the lens of what’s best for the company that took the risk to make the movie. We want repeat business. And awards for a movie that doesn’t get eyeballs is less valuable in the long term than a movie that everybody loved but didn’t get awards.”

The Toronto International Film Festival begins Sept. 5 and runs through Sept. 15. The Grolsch People’s Choice Award is announced on the festival’s final day.