The film chronicles the transformation of a young man from an unruly, selfish, argumentative slacker into a tranquil, introspective individual grieving over his reckless past, thanks to the emotional power of the group's art and the profound insight of their philosophy.

Although Jaycee Chan is to be credited with bringing his character, Sid, to life, it's Bi's deft handling of the drummers' rigorous existence that anchors the film.

Bi is hardly as boisterous as Sid - the filmmaker is actually softly spoken, reflective and, unsurprisingly for a theatre and film studies graduate, well grounded in the performing arts.

Nevertheless, he says he was floored when he first saw U Theatre perform several years ago.

'[It] changed the way I looked at everything,' he says. 'They didn't say anything for two hours and just drummed - but I felt they said so much to me. It's like when a martial arts master comes into a room ... they have an air ... when the guy stands there you feel compelled to stand up.

'It's that kind of rapport - in their presence I felt inspired and in awe, and a little bit ashamed for the shape I'm in. When I look at them, these 12 people looked so concentrated but so empty, they are not thinking about anything.'

Bi was so impressed with the drummers that he ventured to their rural Taiwanese commune to learn more about their beliefs.

'I went to the mountain to tell them that I'd had this huge reaction and when I watched them my whole life flashed right before my eyes - [the performances are] very meditative and hypnotic.

'They explained to me that the vibrations hit your abdomen, your diaphragm and your heart, and jolt your organs and your memories come up. That's a very poetic explanation. I don't know if it's true, but that's what happened.'

Having undergone this change in his own perspectives, Bi came up with the story of Sid, the son of a Hong Kong mobster who goes into exile in Taiwan after an unwise tryst with the wife of his father's rival.

The listlessness he feels being away from bustling metropolitan life gradually dissipates as he becomes enmeshed with a group of drummers living on a mountain near his new home.

A former rock'n'roll drummer, Sid initially takes a gung-ho approach to his art but slowly gives way under the tutelage of the group's leader (played by U Theatre's founder and artistic director Liu Ruo-yu) and develops a bond with junior drummer Hong-dou (played by Malaysian actor Angelica Lee Sin-je, the only non-U Theatre member in the film's troupe).

Working with the drummers was surprisingly easy, even though most of them had never acted conventionally before, Bi says.

'[Liu] was Ang Lee's classmate and schoolfriend at New York University, and she played the lead in Lee's first student film, so she had experience in traditional drama,' he says. 'At first I thought [the drummers] were all like saints and monks, but over the five years I've been interviewing them they've become just so vivid and I don't look at them as an artistic group any more.

'Only when they start drumming do they become one, but then I don't have to look after them, I just put a camera there and shoot.'

For the two lead actors, making The Drummer was a rigorous exercise. Lee underwent weeks of intensive training to be able to do what is expected of a drummer. There was a spiritual aspect to the filmmaking process as well. Bi recalls how even Chan, well known for having inherited his father Jackie's penchant for vivacity, went through a metamorphosis.

'The most telling sign of this was when we cut off Jaycee's hair,' says Bi, referring to the scene that marks Sid's enlightenment.

'He changed; his personality changed. It was really shocking because up until then, during the two or three weeks we were up in the mountains, he was himself. Slowly we saw him change, but when we cut off his hair we all felt the difference. I had hoped I could create an environment in which an actor would change by himself. It had to happen by itself. I didn't engineer it, I was just hoping.'

The fact the film was funded by Emperor Motion Pictures - owned by Jackie Chan's good friend, media tycoon Albert Yeung Sau-shing - might partly account for the availability of Jaycee Chan for the lead role, but Bi says the film could easily have been made without the younger Chan's input.

'I had begun to write a story about a corrupt cop in his 30s from Hong Kong who ends up in Taiwan, like what we have now, saved by the drummers,' he says. 'And I kept writing the story and I kept feeling there was something wrong with it. Eventually, I realised what was wrong was that it's a story about a person in his 30s changing, and I thought it's pretty dull because people in their 30s change all the time. A lot of businesspeople by their mid-30s feel they have been cheated out of their real calling and quit their jobs to travel the world, or whatever. It's too common and not worth investigating.'

Bi hasn't suffered such a meltdown himself. The son of director Chin Han and actor Ivy Ling Po, he was born into a world of film and has scarcely left it since. Having finished a degree in theatre and film at Toronto's Brock University, where he directed and produced an array of student projects, from films to radio plays, Bi returned to Hong Kong in 1995 to help Teddy Robin on Hong Kong Graffiti as a screenwriter and editor.

He was nominated for best musical score at the Hong Kong Film Awards for The Longest Summer in 1999 and in the same year a script he wrote was awarded the outstanding screenplay prize in an annual competition held by Taiwan's Government Information Office. In 2000, the project was entered in the Pusan Promotion Plan - the film market event held alongside the city's film festival - but it wasn't until early 2005 that Rice Rhapsody would finally make its debut in Hong Kong, Taiwan and Singapore.

Five years in the making, The Drummer has premiered at the Locarno Film Festival and soon will screen at the Eurasian Film Festival in Turkey. Given its content and the diversity of its backers - Emperor is co-producer along with Taiwanese and German investors - the picture is destined for more appearances on the festival circuit.

Whether the film is a commercial hit remains to be seen. Bi insists that it's still an independent feature and doesn't see it as his calling card for more mainstream, big-budget productions. 'There are plenty of commercial filmmakers to go around,' he says.

'When they see you're doing your own stuff they don't know what to come to you with. If it's a cops-and-robbers thriller, maybe I'm not the first person they would think of. If it's a family drama, maybe it'll go to Ann Hui. I mean, I create my own opportunities.'

The Drummer opens on Oct 11