Director: Damien Chazelle
Cast: Miles Teller, J.K. Simmons
Certificate: 15

Jazz is all about timing. Many people think it's solely made up on the spot, any-which-way-you-fancy improv, but a large chunk of it is also written down. There are chord progressions, standard songs, time signatures. If you want to make it over the top - to become really, truly great - you first have to understand the rules of engagement. The question, though, is how you go about it.

No one knows the law of the battlefield like Fletcher (J.K. Simmons). The hardened conductor lords it over the Shaffer Conservatory's best big band with a fist of brass. Brass covered in blood. So when young pupil Andrew (Miles Teller) manages to sit on the group's coveted drum stool, he's determined to stay there - and Fletcher's determined to make him earn it.

How? Practice. You need to devote time so you can keep time - something that most films about music seem to forget. Usually, biopics present us with famous musicians who go through personal trials and tribulations, only to emerge the other side a fully-formed artist. It's a treat, then, to see a film about the practical nature of music, one that plays out like the messy underside of that artificial drum; the side with the snare on it.

"Are you rushing or dragging?" Fletcher interrogates Andrew, as they rehearse the titular track by Hank Levy. He asks over and over, like a drill sergeant auditioning for Full Metal Jacket: The Musical.

Simmons is terrifying, a wide-eyed brute whose foul-mouthed insults are as hilarious as they are intimidating. Anyone who has ever had a bullying music teacher - and (speaking from personal experience) they do exist, albeit not as extreme as this - will immediately recognise the fear of playing a wrong note and the disappointment of both letting your mentor down and, worse, yourself. But there is a universal intrigue to that process, the unseen way in which talent in any field develops - which, in Whiplash's hands, is arranged as a thrilling piece of physical, human drama. (In the words of Alan Partridge, crash, bang, wallop. What a video.)

Teller, who can play the drums in real life, is sensational as the eager student, a boy so focused that he shuts out all other concerns: family tensions and romantic dates are all ignored by him and the blinkered script follows suit. The only thing that matters here is the music.

Grimacing, laughing and sweating profusely, the young star is astonishing to watch in action - not only acting while playing the drums, but appearing out of sync believably enough to spark Fletcher's wrath. Together, the pair form a dazzling duet, riffing off each other, as Teller's drumming becomes tighter and their relationship changes key, from nasty humour to just plain nasty.

All the while, director Damien Chazelle keeps tempo - a breakneck metronome that, like Justin Hurwitz's score (including a selection of standards, such as Caravan), is a toe-tapping masterclass in precision. As Andrew gets better, pushed by this monster with a manuscript, Chazelle's camera shoots across the kit, bouncing off the hi-hat and toms with its own fascinating rhythm.

The pair, the screenplay reveals, are labouring under the (misunderstood) legend of Charlie Parker, who was given the push he needed to become Bird by Jo Jones lobbing a cymbal at his head. Aren't they missing the point altogether? After all, jazz needs soul as well as skill. It helps if all your body parts are intact too.

The director skilfully modulates the tone from unnerving comedy to sceptical horror, but the real crescendo occurs with the last movement, a blistering dash to the closing bar that finally throws all that rigid conducting out of the window and goes for a freewheeling rim-shot to the gut. Mention jazz to most people and they'll switch off, dismissing it as made-up noise. Whiplash, though, brings the house down every time. It's all about timing. And it doesn't miss a beat.