How do you make a compelling film when your lead character is trapped by a boulder and unable to move for most of the story?

Director Danny Boyle, coming off the success of the Oscar-winning film "Slumdog Millionaire", rose to the challenge with his fact-based feature, "127 Hours", which premiered at the Toronto International Film Festival this week.

"There's something I love about that idea, of that inability (to move) at the center of a film," he told Reuters in an interview.

"It's an extraordinary challenge to a filmmaker and an actor. There's an inertness, which completely contradicts what film is ... it's movement through the camera, everything is moving all the time," Boyle said.

"127 Hours," which opens across North America on November 5, is a harrowing yet uplifting film about the survival of mountaineer Aron Ralston, 34, whose right arm became pinned during a 2003 hiking trip in an isolated Utah canyon.

After days of trying to dislodge himself, Ralston cut off the lower portion of his arm using a dull blade and then hiked until he found help.

The audience spends a good portion of the 94-minute film trapped alongside Ralston, played by James Franco, in a single spot within a narrow crack inside Blue John Canyon.

When Franco first read the script, it was roughly 80 pages of mostly description. He wondered, "How am I going to use that kind of material and make it dramatic, make it tell a story?"

"It's a very tricky thing to be able to turn that into something that's full of energy and ups and downs," Franco said during the interview.

Boyle and screenwriter Simon Beaufoy used monologues with a video camera and visions to draw viewers into Ralston's experience.

The video diaries were based on real video entries Ralston made during his experience and are told from the perspective of someone who thought he would die in the canyon.

Boyle said the video camera was like having another character. Along with a bird that flew above in the mornings, the camera was Ralston's only relationship.

"With the video diary, it was a chance for the character to really just pour his heart out," Franco, adding that some of the entries were fictionalized. "Who's to say he didn't have a message where he broke down or did some crazy things and then went back and erased it?"

"I think he wanted to leave a dignified last message for his parents if he could," Boyle added.

Interspersed with the diaries and Ralston's attempts to extricate himself are visions that he has of his friends and family, past memories, and his future son, who Ralston said during a press conference on Sunday was ultimately what motivated him to make that final, desperate push to escape.

Franco, who has been perpetually busy with film and TV projects and recently started a Ph.D. in English and film studies at Yale University, won the role after giving a very moving reading of one of the video diaries, Boyle said.

"As soon as I heard him read it, I thought, that's him."