Story highlights Coroner: Paul Walker died from "combined effects of traumatic and thermal injuries"

Autopsy confirms Roger Rodas was driving the Porsche when it crashed

Walker's and Rodas' deaths ruled an accident by the coroner

Production of the next "Fast & Furious" film is shut down "for a period of time"

"Fast & Furious" star Paul Walker may have initially survived a horrific car crash but died moments later of a combination of injuries from the impact and the resulting fire, according to a coroner's report.

The one-page preliminary report released by the Los Angeles County coroner's office Wednesday listed the cause of the actor's death as the "combined effects of traumatic and thermal injuries."

An autopsy concluded that Roger Rodas , who was driving the red Porsche Carrera GT, suffered "multiple traumatic injuries," but it was not clear in the report if he was still alive when the car burst into flames soon after the wreck.

Since two different doctors did the separate autopsies, the difference in the description of their injuries does not mean the deaths were significantly different, Los Angeles County Assistant Chief Coroner Ed Winter told CNN.

It is not known how long each man lived after the crash as the fire began, Winter said. That information may be included when full autopsy reports are released in several weeks, he said.

The coroner confirmed what many witnesses told investigators: Rodas was the driver in the crash; Walker was the passenger of the high-performance Porsche that clipped a light pole and a tree before erupting in flames on a Southern California street Saturday afternoon.

Photos: Paul Walker: Life in the fast lane Photos: Paul Walker: Life in the fast lane Paul Walker, a star of the "Fast & Furious" movie franchise, died in a car crash on November 30, 2013. He was 40. Here's a look at his career through the years. Hide Caption 1 of 15 Photos: Paul Walker: Life in the fast lane Walker with Tyrese Gibson, Michelle Rodriguez and Ludacris in "Furious 7," which had mostly completed filming when Walker died. Many fans got emotional upon seeing Walker onscreen in the movie, which earned $143 million its first weekend. Hide Caption 2 of 15 Photos: Paul Walker: Life in the fast lane Walker's role as Brian O'Conner in the "Fast & Furious" franchise (here with Vin Diesel in the sixth film) helped make the actor a star. Hide Caption 3 of 15 Photos: Paul Walker: Life in the fast lane Walker and Jordana Brewster -- who played his love interest, Mia, in the films -- in "Fast 5." Hide Caption 4 of 15 Photos: Paul Walker: Life in the fast lane Kevin Rankin and Walker appear in "Pawn Shop Chronicles," a 2013 film about a missing wedding ring that sets off a wild goose chase. Hide Caption 5 of 15 Photos: Paul Walker: Life in the fast lane Walker also had a starring role in the 2013 film "Hours," about a man trying to keep his daughter alive after Hurricane Katrina. Hide Caption 6 of 15 Photos: Paul Walker: Life in the fast lane The actor was part of a band of thieves in the 2010 movie "Takers." Hide Caption 7 of 15 Photos: Paul Walker: Life in the fast lane Brooklynn Proulx and Walker in the 2008 film "The Lazarus Project." Hide Caption 8 of 15 Photos: Paul Walker: Life in the fast lane Walker, left, and Barry Pepper were U.S. Marines in the 2006 drama "Flags of Our Fathers." Hide Caption 9 of 15 Photos: Paul Walker: Life in the fast lane Walker appears in the 2005 action film "Into the Blue," which also starred Jessica Alba. Hide Caption 10 of 15 Photos: Paul Walker: Life in the fast lane Tyrese Gibson took over for Diesel opposite Walker in 2003's "2 Fast 2 Furious." Hide Caption 11 of 15 Photos: Paul Walker: Life in the fast lane Walker appeared in 2001's "The Fast and the Furious," the first movie in the franchise. Hide Caption 12 of 15 Photos: Paul Walker: Life in the fast lane Walker, center, appeared in "Skulls" with Leslie Bibb and Joshua Jackson in 2000. Hide Caption 13 of 15 Photos: Paul Walker: Life in the fast lane Walker and Freddie Prinze Jr. co-starred in the popular 1999 teen film "She's All That." Hide Caption 14 of 15 Photos: Paul Walker: Life in the fast lane Walker's first major role was opposite Reese Witherspoon in the 1998 film "Pleasantville." Hide Caption 15 of 15

The deaths were officially ruled an accident by the coroner.

A toxicology report, which could show if drugs or alcohol played a role in the accident, will be available in six to eight weeks, the report said.

Video obtained by CNN from a security camera posted on a building on the opposite side of the street from the crash suggests that the fire that engulfed the Porsche did not erupt until about a minute after the car crashed.

In the video, which does not show the car, black smoke is seen rising from the crash scene 60 seconds after the light pole and a tree fall. Smoke is faintly visible above the scene after one minute, followed by a heavy plume of black smoke after two minutes.

The crash happened on a wide street in a business park in Santa Clarita, California, about 30 miles north of Hollywood. Walker was attending a holiday toy donation event for his charity, Reach Out WorldWide, when he hopped into the car with Rodas for a ride, witnesses said.

The Porsche, which was one of only a few hundred made, was on display at the event, which was held at a high-performance car shop owned by Rodas.

Minutes after the two men drove away, people at the event heard the crash about 500 yards away, witnesses said.

Next 'Fast & Furious' on hold

Production of Walker's latest movie -- the seventh installment in the "Fast & Furious" franchise -- will be shut down "for a period of time," the studio said Wednesday.

"At this time we feel it is our responsibility to shut down production on 'Fast & Furious 7' for a period of time so we can assess all options available to move forward with the franchise," Universal Pictures said in a statement.

The studio also said it would donate "a percentage of proceeds from the upcoming home entertainment release of 'Fast & Furious 6'" to Walker's charity

"With the passing of Paul, the world has lost a man who spent a great deal of his life in service to others," Universal Pictures Chairman Donna Langley said. "We share in the deep grief of his family, friends and the countless fans who love him."

Stories of Walker's incredible generosity have become a major aspect to coverage of the actor's death.

CNN confirmed one story from a decade ago when Walker noticed a young U.S. soldier shopping with his fiancee for a wedding ring in a Santa Barbara jewelry store.

"The groom was just back from duty in Iraq, and he was going to be deployed again soon and wanted to buy a wedding ring, but he said he just could not afford it," saleswoman Irene King told CNN. "I don't think the soldier realized how expensive those rings are, about $10,000."

"Walker called the manager over and said, 'Put that girl's ring on my tab,'" she said. "Walker left all his billing info, and it was a done deal. The couple was stunned. She was thrilled and could not believe someone did this."

King called it "the most generous thing I have ever seen."

Walker and Rodas had planned Saturday as a day to help survivors of Typhoon Haiyan in the Philippines. The car shop website invited customers to a "Charity Toy Drive & Automotive Social Gathering."

Box office success

Walker's career began on the small screen, first with a commercial for Pampers diapers when he was 2, and then with parts in shows such as "Highway to Heaven" and "Touched by an Angel."

His first few movie roles were as supporting characters in teen flicks, most notably in "Varsity Blues." But his career really took off when he was cast as undercover cop Brian O'Conner infiltrating a street-racing gang in 2001's "The Fast and the Furious."

The box office success of the surprise summer hit yielded numerous sequels. And along with Vin Diesel, Walker was one of the franchise stalwarts. The six "Fast & Furious" films sold a total of $2.6 billion in tickets worldwide, according to BoxOfficeMojo.

Walker wasn't just a car enthusiast on the silver screen; off screen, the actor competed in the Redline Time Attack racing series.

On his verified Twitter account, Walker described himself as an "outdoorsman, ocean addict, adrenaline junkie ... and I do some acting on the side."

Walker also is the star of "Hours," an independent film scheduled to be released December 13 about a father struggling to keep his newborn infant alive after Hurricane Katrina in New Orleans.