The "Director's Cut" in this case is, as often, more like the director's stretch as the already lavish fictionalised Mozart biopic now runs to three hours of non-stop fortepiano and whalebone corset action. Luckily, the elongation doesn't cause any holes to develop; where the film threatens to become bogged down in a froth of frills (of the orchestral, fantastical and haberdashery varieties) it is borne onwards time and time again by the sheer power of Mozart's music, which after all people regularly listen to for hours on end without much to look at but the conductor's coat-tails.

In some scenes - as where Tom Hulce as Mozart furiously conducts Don Giovanni's inexorable black apparition which, it is explained, is the operatic incarnation of his dead taskmaster/father Leopold - "Amadeus" is an impelling programme note which allows the veracity of the music to speak for itself. Sparkling performances from the best-known operas (the Queen of the Night and Papageno get a good showing) and sacred works contrast starkly with the vulgar, giggling drunkard and wastrel Mozart is portrayed as having been. Indeed, biographically speaking the film is hardly a study of Mozart himself at all. The jealous Salieri, who worships the composer to the point of destruction, is a much stronger character: deeply bitter, but just far enough from having turned completely sour that he becomes strangely and agonisingly sympathetic. His hatred is rooted in wilful self-frustration - having seen that God does not reward abstinence with musical talent, as he had once believed, Salieri takes a twisted pride in thrusting aside all sexual opportunities that fall into his path, even with his hated rival's wife. To him such victories would be pointless whilst his art was still outclassed by the other man's. Yet he remains on both counts a figure of intense, tangible longing.

One aspect of the film that is often overlooked by concentrating too hard on the campaign of vengeance Salieri wages is the genuine love and even worship that he also exudes towards his rival composer. Gifted enough to be deeply, even physically incapacitated by the beauty of Mozart's music in manuscript form, he obsessively attends each opera even whilst working to have it removed from the stage. As the dying Mozart dictates his Requiem with Salieri as amanuensis, there seems at last to be an instinctive understanding between the two in capturing the creative idea; and when Mozart whispers thanks for the appreciation of his music, Salieri's duplicity somehow ceases to matter: at heart there is truth in it. His bitterness is due not just to envy, but to the fact that Mozart as a debt-ridden drunkard defiles the purity and "divinity" of his art.

This revision for the 2002 release is relatively minor, with new scenes illustrating the conflict without altering it: one shows Salieri's amusing attempt to return the humiliation he has received by sending Mozart to teach at a house where every note he plays triggers a cacophony of barking dogs. More interesting is how the context of the film has changed: in 1984 "Amadeus" helped shape many people's ideas about the personality and life of Mozart, and now it will be watched in the light of those ideas. It is less interesting as speculative music history than as a richly illustrated study of genius, of compensation for its absence, and of the intense love and hatred we feel for our idols. Whatever factual evidence may one day arise, Salieri will forever be the Mark Chapman of Classical Vienna.