Robert Redford's Oscar snub notwithstanding, the 30th Sundance Film Festival is off to a promising start.

The 10-day showcase of independent film began Thursday in Park City, Utah, where sunny skies and a Main Street filled with film-related shops and suites welcomed festival-goers.

Redford and other Sundance leaders said the festival's greatest success has been providing a place for independent film to be seen and celebrated.

The festival has expanded its offerings over its three decades, both in the number and types of films shown.

Opening day features five screenings: Domestic and international dramas and documentaries and a collection of short films.

Opening film

2014 Sundance Film Festival - Whiplash Premiere

Cast member Miles Teller poses at the opening night premiere of the film "Whiplash" during the 2014 Sundance Film Festival, on Thursday, Jan. 16, 2014, in Park City, Utah. (Danny Moloshok/Invision/Associated Press)

Miles Teller — who can be seen on screen later this month with Zac Efron in That Awkward Moment — took four-hour drum lessons three times a week to play the lead in Whiplash, shown opening night.

Teller plays a jazz drummer determined to succeed, whether because of or in spite of an unforgiving instructor, played by J.K. Simmons at his most intimidating (and muscular). Attending the country's most prestigious music academy, Teller's character, Andrew, aspires to be one of the greats, playing until his hands bleed. Simmons is Fletcher, a teacher prone to belittling his students in an effort to unearth their determination and will to improve.

Writer-director Damien Chazelle said he told Simmons: "Just scare us."

The 28-year-old Chazelle, whose short film of the same title and subject won an award at Sundance last year, is also a drummer who drew from personal experiences for the story.

The original film "basically helped us get in the conversation with, like, financiers and people who might want to take a risk about a movie about a drummer," Chazelle said. "Without the short, I don't know if we would be here."

Teller described the film as "a pretty intense, dramatic almost, like, thriller environment for conservatory jazz music."

As for his co-star?

"J.K. Simmons is pretty terrifying," Teller said.

Paul Reiser co-stars as Teller's loving dad — one of two movies Reiser appears in at Sundance. The other is the dark comedy Life After Beth.

Both Life After Beth and Whiplash are candidates in the festival's U.S. dramatic competition. Winners will be announced on Jan. 25.

Sony Pictures Worldwide announced it acquired international distribution rights to Whiplash just after its premiere.

Honouring Ebert

Ebert Documentary

Roger Ebert, center, his wife Chaz, left, and their granddaughter Raven Evans, arrive for the Chicago premiere of the the Broadway hit "The Color Purple," May 3, 2007. (Charles Rex Arbogast/Associated Press)

Ten months after Roger Ebert's death, the famed film critic will be the subject of a documentary debuting Sunday.

Life Itself is directed by Hoop Dreams filmmaker Steve James. It includes footage that James gathered during the last four months of Ebert's life.

The longtime Chicago Sun-Times movie critic died in April after a long battle with cancer.

But the crowds at Sundance won't be the only ones watching the premiere. Filmmakers tapped into Ebert's wide online following to crowd fund $150,000 for production costs. Donors will receive a code to stream the film online at the same time it premieres at Sundance.

Life Itself will have screenings next month in New York, Los Angeles, Chicago and Ebert's hometown of Urbana, Ill.

Screenings of this year's 117 feature-length films continue from morning until night at 14 locations in Park City through Jan. 26.