This happened in 2015, but I only found out today.
Pierre Jansen was a French composer working in film. He was in particular the permanent collaborator of Claude Chabrol for whom he composed the music for many films.
He also scored the above documentary Acera, or the Witches’ Dance (1972) by Jean Painlevé.
André Previn was a German-American musician best known for his film scores.
He first came to my attention when his ex-wife Dory Previn died in 2012.
After some quick glancing through my archives, I find that a ‘porn groove’ on the compilation The Mood Mosaic Vol. 3 “The Sexploitation” is of Previn’s hand, a track called “Executive Party” composed for the film Rollerball.
In the clip above that song is heard in a wonderfully strange scene “shot in the pre-dawn “magic hour,” as the wealthy, decadent upper-class fire explosive rounds at a line of towering trees, setting fire to them one after another, reveling in destruction” [1].
A example of pure wanton waste of excess energy.