Beethoven shows up at Bonn Station in 1970 to survey how the culture industry is marking his bicentenary. That delicious conceit is the basis for Ludwig van, Mauricio Kagel's miraculous film now available for the first time on DVD. Beethoven himself holds the wobbly camera during the first section of the film, and we only ever get to see his buckled shoes as he minces through the streets.

There are road works outside the Beethovenhaus as Our Hero visits his erstwhile lodgings and has to hotfoot it over barriers (another great joke at the expense of Beethoven's dainty feet) to reach his front door, where he's met by a jobsworth doorman who insists he buy a ticket. Kagel is the composer who made Bach the narrator of his own story in the St Bach Passion and he's relishing this historical gibberish. Incongruous historical overlays provoke high comedy while creating weird Philip K Dickian reality-busting narratives. But most importantly this technique licenses Kagel to unravel the trajectory of evolving traditions; and the slapstick over, he gets dark.

Inside the house, Beethoven is confronted by rotting busts of his own form everywhere while sheet music tumbles out of a cavernous cupboard - in his bicentenary year is his music being celebrated or exploited? Ludwig van's most famous scene is next as the camera zooms into Beethoven's music room where every surface is pasted with fragments of his scores. Until now Kagel's music has consisted of jokey arrangements of LvB lollipops for a wheezing wind ensemble, but now musicians follow the direction of the camera as it pans around these haphazardly arranged scores. Musical syntax breaks down and familiar phrases are mulched into a chaotic soundscape that curiously re-energises them as empiric sources of sound.

Another narrative jump and Kagel is featured in an earnest television show discussing Beethoven; one guest puts the boot into Karajan (a particular hate figure for the post-Darmstadt avant-garde) for conducting the orchestra rather than the score. Kagel looks on with gleeful mischief beaming from both eyes.

Alongside the DVD are two CDs of remastered near-contemporaneous material - the first documents Kagel's own performances of three intriguing works climaxing in Bestiarium: Music for Bird Calls, while the second is his seminal, hyperactive radio piece (Hörspeil) Ein Aufnahmezustand. Of course, it's a paradox worthy of Kagel himself that this set is released to celebrate his own 75th birthday - geddit?