The awards-givers have started to weigh in, and there are many questions (are these Oscar omens?) and talking points (surprise omissions, etc.).

One of the questions so far this year is a perennial one: whether certain performances should be considered lead or supporting.

Marion Cotillard in “Nine,” for example, was nommed as supporting actress in the Critics’ Choice Awards, but lead in the Golden Globes.

Last year, Kate Winslet won a Globe and SAG Award as supporting actress for “The Reader,” but Oscar and BAFTA voters put her in the lead category for that film.

Similarly, BAFTA nominated Dev Patel as lead for “Slumdog Millionaire,” but SAG nommed him as supporting. Patel was MIA in Oscar noms — maybe Acad voters didn’t know where to put him.

Some of the debates are due to confusion, some due to backstage politics. And a lot is due to the changing nature of the movie biz.

In the 1930s and ’40s, studios had stars (Bette Davis, Clark Gable) and supporting players (Peter Lorre, Walter Brennan). All of them were under contract, all of them understood the studio hierarchy. And the size of their roles reflected their status.

During that era, the Academy of Motion Picture Arts & Sciences invented the supporting categories. But over the years, the notion of contract players became extinct, and the lines blurred.

There are several factors in the confusion.

1) Ensemble movies: These films mean that every actor has limited screen time, even though they might be considered a protagonist. In the first ads for “Lord of the Rings,” Ian McKellen was touted as lead, but he and New Line wisely changed the campaign to make him supporting. In “The Departed,” voters weren’t sure where to put Leonardo DiCaprio, Jack Nicholson and Matt Damon, and none was nommed.

2) Age: Awards voters tend to put youngsters in supporting categories. In “The Sixth Sense,” Haley Joel Osment, like Timothy Hutton a few decades before him (“Ordinary People”), was nommed as supporting, though that was a lead. And there was debate whether Keisha Castle-Hughes, 15 for “Whale Rider,” should be considered supporting or lead. She wound up in the latter (and rightly so).

3) Sometimes it’s to avoid conflict: Cate Blanchett and Judi Dench in “Notes on a Scandal,” Jake Gyllenhaal and Heath Ledger in “Brokeback Mountain,” Samuel L. Jackson and John Travolta in “Pulp Fiction”: All had roughly the same screen time, but the studios wanted to avoid crowding one category. And there can be other types of conflict. Julianne Moore in “The Hours” was touted as supporting, while Meryl Streep was the lead. Moore was probably on camera more, but there’s a reason for her categorization: She had “Far From Heaven” that year.

There are no clear-cut delineations. Last year, Philip Seymour Hoffman won a supporting Oscar nom for “Doubt,” though the role had garnered a lead nom in Tony voting. The same thing had happened with Jennifer Hudson and Catherine Zeta-Jones: supporting winners in film, but leads on Broadway. Years ago, Yul Brynner won a supporting Tony for “The King and I,” but won a lead-actor Oscar.

In “Fargo,” Frances McDormand was onscreen for 32 minutes, less time than William H. Macy. Yet she was nominated as lead, he as supporting. Like Anthony Hopkins in “The Silence of the Lambs” and Marlon Brando in “The Godfather,” McDormand could have been considered supporting, but the character was so vivid, that’s what audiences remembered.

Some have expressed surprise that Judi Dench and Beatrice Straight could win Oscars with such limited time onscreen (less than 10 minutes each). But why not? I personally wish there were more recognition for actors who make maximum impact with minimal screen time, like this year’s Guy Pearce in “The Hurt Locker” and “The Road,” or Adriane Lenox (as the football player’s druggie mother) in “The Blind Side.” They’re terrific, but it’s doubtful they’ll get awards attention. In the past few years, Vanessa Redgrave gave two astonishing performances, in “Venus” and “Atonement,” but she was overlooked in awards attention, presumably because her time onscreen was so brief. Meanwhile, good luck to all the hopefuls, and have a happy holiday.