“The Artist,” a love letter to Hollywood, got hugs, kisses and the best-picture Oscar on Sunday at the 84th Academy Awards ceremony here. The film also took the awards for best actor and best director, in a minisweep that found the movie industry paying tribute to not just the movie but to its own roots as well.

“I want to thank Billy Wilder, I want to thank Billy Wilder and I want to thank Billy Wilder,” said Michel Hazanavicius, the film’s director, in keeping with a self-referential theme that ruled the evening.

Thomas Langmann, the producer, accepting his award for a mostly silent, black-and-white fable about an actor’s struggle with the end of silent film, said the achievement was dedicated to his father, the deceased French director Claude Berri.

Until Sunday no silent film had won the top Oscar since “Wings,” at the first Academy Awards ceremony in 1929. But nostalgia ruled the night, as “Hugo,” about another silent star, Georges Méliès, won a string of less prominent awards, and “Midnight in Paris,” a comic time trip to Paris in the 1920s, took the prize for original screenplay for Woody Allen.

Meryl Streep, a winner for her portrayal of a doddering Margaret Thatcher in “The Iron Lady,” made her victory look like a shock. But she hadn’t won since 1983, even though she reigns as the actor with the most nominations in the history of the Academy of Motion Picture Arts and Sciences, with 17 in all. Ms. Streep said she could imagine half of America gasping: “Oh no! Oh, come on! Why her? Again?” as her name was read.

When the only surprise is a victory by Ms. Streep, you know things are going by the script. Viola Davis, for her work in “The Help,” had been considered a strong candidate as the best-actress winner.

“Merci, beaucoup, I love you!” shouted Jean Dujardin, as he picked up his award as best actor for a movie that was conceived in France, but showered its adoration on the Hollywood of yore.

After a dry spell in the early evening, “The Artist” gained momentum as the major awards were presented, beginning with a prize for Mr. Hazanavicius. The winner unscrolled a long string of French-accented “thank yous” that included Uggie the dog.

Christopher Plummer, born in 1929, won his first Academy Award, as best supporting actor, for “Beginners.” “You’re only two years older than me, darling — where have you been all my life?” said Mr. Plummer, in picking up a statuette that was first given for films made in 1927 and 1928.

It was long overdue recognition for Mr. Plummer, who had appeared in dozens of films over more than 50 years, and finally won for his portrayal, in “Beginners,” of a father who in his final years acknowledges being gay.

“Congratulations to Mr. Plummer; the average age of the winners has now jumped to 67,” joked Mr. Crystal.

That was before Woody Allen, 76, won a best original screenplay Oscar for “Midnight in Paris,” bumping the average age still higher. That film was another nostalgia trip, about literary Paris in the 1920s. In keeping with a personal tradition, Mr. Allen was a no-show, and left the Academy to accept its own prize on his behalf.

Closer to present time, Alexander Payne, Nat Faxon and Jim Rash had just won an adapted-screenplay Oscar for “The Descendants.” It was welcome recognition for a movie that once appeared among the front-runners for best picture, but seemed to falter as a grueling, monthslong campaign season showered pre-Oscar prizes on “The Artist.”

There was a dollop of drama to the proceedings.

As the show passed its midpoint, “Hugo” had made the only show of force. A 3-D tale, set in Paris, it had won five Oscars, for cinematography, art direction, sound editing, sound mixing and visual effects.

Meanwhile, two hours in, “The Artist,” supposedly the night’s front-runner, had won only two awards, those for its Jazz Age costume design and musical score. If the early snubs sent a shiver through Harvey Weinstein, whose company distributed “The Artist” in the United States, he could take comfort, at least, in a win for “Undefeated.”

That film, about a black urban high school football team and its white coach, was also distributed by the Weinstein Company, and took the Oscar for best documentary feature. One of the film’s makers drew a gasp in the auditorium when he broke Oscar protocol by tossing off a strictly forbidden obscenity — something rare at the tightly controlled Academy Awards.

Chris Rock followed with a racial joke, about black men getting lousy roles even in animated films. It may have been in questionable taste, but it jarred the show closer to modern times.

“Rango” was the animation winner, from the director Gore Verbinski and Paramount Pictures. Both DreamWorks Animation, which had “Kung Fu Panda 2” in the running, and Walt Disney’s Pixar Animation, which had no nominee in the category at all, had watched their grip on the prize slip to Mr. Verbinski, who had never before made an animated film.

Elizabeth Taylor was the capper in an especially crowded memorial sequence that paid tribute to one after another among the film figures who died in the last year. The actor Ben Gazzara, the movie executive John Calley, and the Oscar show producers Gil Cates and Laura Ziskin were among them.

Finally, the show settled into its inevitable rhythm of presentation, thanks, and congratulatory applause — in a typical Oscar broadcast, only a relatively small sliver goes to production numbers and pranks by the host. But the montage moments kept coming.

As the end neared, actors like Julia Roberts and Robert Downey Jr. were on film carrying on about why they love film. “I’ve never had any of those feelings,” said Mr. Crystal.

And the demographic jokes never stopped. “Perky gets old fast with this crowd,” Ben Stiller warned Emma Stone, as she milked a bit that wound around her status as a first-time presenter.

Indeed it was a mirth-by-any-means-necessary kind of night: Will Ferrell, Tina Fey, Chris Rock, Kristen Wiig, Kermit the Frog and a parade of other comedians were among the presenters.

Mr. Crystal, his vaudeville grin firmly in place, set the tone early, opening the show with a song-and-dance montage that managed to send up the nine best-picture nominees, Tom Cruise, the movie “Bridesmaids,” and his own aging career all at once.

“This is my ninth time, my ninth time hosting the Oscars,” he quipped in an opening monologue that seemed bent on leaving no one out. “Just call me ‘War Horse.’ ” Pointing one of his barbs directly at the film industry, he added, “Nothing can take the sting out of the world’s economic problems like watching millionaires present each other with gold statues.”

The theater was gilded and draped in red, as were many of the starlets. The idea was to mimic a glamour that came with the movies of old — a time when, perhaps, they mattered a little more than they do in an age of multiplatform entertainment.

The big show-business smile that infused the ceremony was more than a ratings ploy. It was also an effort by the Academy to move past a tumultuous Oscar season that left the organization bruised if not bloodied.

Mr. Crystal came aboard as host at the last minute in November, pinch-hitting for Eddie Murphy, who dropped out when Brett Ratner, his friend and a producer of the show, resigned amid a media storm over his use of an anti-gay slur at a panel discussion in Hollywood. Simultaneously, the normally staid Academy had to deal with infighting over its new chief executive, Dawn Hudson, and the changes she was trying to implement. Ms. Hudson finally defended herself a few days ago in an interview with The Hollywood Reporter.

A generally weak box-office performance among the year’s nine best-picture contenders — only one of which, “The Help,” amassed more than $100 million in domestic ticket sales — had already caused worry about the Oscar show’s ratings potential. Then moviedom took an added blow to its confidence, watching this year’s Grammy Awards show attract about 40 million viewers as music fans rallied around the death of Whitney Houston; last year’s Oscars drew 37.9 million viewers.

Meanwhile, a demographic survey by The Los Angeles Times renewed questions about the 5,800-member Academy’s cultural relevance. Membership was found to be overwhelmingly white, male and 60ish. The results echoed conventional wisdom, but provoked new debate about whether the Oscars still mattered to an increasingly diverse America, let alone a global audience.

The television ratings may provide a clue. (At 3 hours 8 minutes, the show ranked among the shorter broadcasts in recent history.) In the meantime, the longing for past glory was perhaps most wistfully expressed by Bret McKenzie, whose composition, “Man or Muppet,” won for best original song.

Backstage, Mr. McKenzie modestly allowed that his song, for the film “The Muppets,” couldn’t hold a candle to Paul Williams and Kenneth Ascher’s “Rainbow Connection,” which has been Kermit the Frog’s theme song through the years.

That song was a classic, Mr. McKenzie said; his own, he contended, was nothing by comparison. Somewhere in that was a lesson for the night.