Director Danny Boyle’s inspiring survival drama “127 Hours” is based on the incredible true story of Aron Ralston, who became trapped alone in a Utah canyon for days after slipping on a loose rock, and resorted to extraordinary measures in order to make it out of his dire predicament alive.

It may sound gruesome and uncomfortable — the film is probably OK for older teens but too intense and graphic for the younger set — but Boyle makes the story almost exhilarating, and certainly inspirational.

Ralston, who was a veteran outdoorsman, understood he had little choice if he wanted to live. The crevice he had fallen into was remote; so he used the blade of a cheap multipurpose tool to cut off his immobilized arm between the elbow and the wrist, freeing himself after more than five days.

Boyle cleverly juxtaposes this slow, grisly endeavor with rapid cuts of memories and hallucinations. Casting Oscar nominee and this year’s Oscar show co-host James Franco was probably his best cinematic choice. The actor’s freewheeling performance as the adrenaline junkie Ralston propels the film.

An amiable fellow, the outdoorsman narrates his travails into a small video camera, at times slipping into the fantasy of believing himself as part of a TV interview show. At other times he goes over his past, seeing what his drive may have cost him with his parents and girlfriends.

But Boyle, a kinetic filmmaker who doesn’t mind tackling difficult subjects — the poverty in the Oscar-winning “Slumdog Millionaire,” for instance — ultimately gives “127 Hours” a joy-to-be-alive feel despite the agony that came before. A lively score by A.R. Rahman helps.