T he minute you hear Christopher Walken intoning the opening stanzas of Burnt Norton ? one of TS Eliot's own late quartets ? you sense that A Late Quartet plans to mine every last meaning from the words in its title. "Late" like the autumnal, musical Eliot of Four Quartets; like the demanding, crepuscular Beethoven quartet the film's characters rehearse for their silver-anniversary performance (String Quartet No 14 in C sharp minor ? menacingly referred to as "Op 131"); and "late" in the connected senses of former or dead, which this quarrelsome foursome soon might be if they fail to recover their harmony. The number four gets a fair old workout as well: four players, four solos, four movements, four rehearsals, Four Quartets. All the film lacks, quartet-wise, is a sweaty menage a quatre among the bow rosin and scoresheets.

The story centres on a well-respected New York string quartet, together for a quarter of a century, which falls into disarray when Peter (Christopher Walken), their founder-mentor-cellist, is diagnosed with early-stage Parkinson's disease. A turf war soon heats up between first and second violinists Daniel and Robert (Mark Ivanir, Philip Seymour Hoffman) about switching chairs occasionally. Tensions between Hoffman and his violist wife Juliette (Catherine Keener) over long-suppressed resentments also emerge, even before they learn that their daughter Alex (Imogen Poots) is sleeping with Daniel.

What could have been stodgy, clunky, obvious and miserable to boot is saved by the deftness of the script and particularly by the organic quality of the snugly interlocked ensemble performances. Walken's fatherly, gently commanding quartet leader is maybe the sweetest, wisest character he has played since his 1962 time-warp dad in Blast From The Past. The shock and grief the news of his debility causes for his proteges is palpable, as is the depth of their regard for him. Keener and Hoffman make a plausibly grouchy-affectionate couple, each wondering about paths not taken 25 years earlier, while Daniel is the group's fanatic purist, a violin-maker and teacher, insistent on emotional engagement with the music and the composer, but in the group's social dynamics he usually plays the devil's note.

If anything in this sad, beautiful sunset-minuet is lacking, it's humour (though there is wit). The actors play Beethoven like they're embalming a corpse, approaching the music far more reverently and glumly than real musicians do. You wish for some split-second equivalent of that famous footage of Du Pre, Barenboim, Mehta and Perlman joking around backstage in 1969 ? two playing the same violin, one bowing, the other fingering, both laughing ? then walking onstage 10 seconds later and leaping into Schubert's Trout Quintet, note perfect.