If it's based on the movie, it would be considered a "derivative work" for which they would need a license. And if Pink Floyd says in an interview that they based their song on the movie, that might be all the plaintiff would need to demonstrate that it was derivative. Pink Floyd would then probably be stuck claiming "fair use" as a defense, which has been narrowly construed by the courts, especially for large scale commercial works.
Meddle has sold like 3 million copies worldwide, so the potential liability is non-trivial. edit: although copyright law may be different for the non-US sales.
9apps vidmate
It doesn't need to be that complicated. It could have been as easy as writing down the approximate timing for the transitions in the film and then roughly cutting their song to fit. The way Meddle was written (being composed in separate pieces that were then stitched together) would make this even easier.
And it doesn't need to be precise to the 0.1 second. If you watch it (seriously, have you watched it recently? That could end the argument), you see that the transitions are sometimes a second or so off (but very clearly transitioning with the film).