'The center of the movie, however, is the music. Tavernier, Maxine Gordon writes, “insisted that all the music would be recorded live as the musicians were filmed.” The musicians in “ ’Round Midnight” don’t play watered-down jazz. Although the numbers are condensed, much shorter than is usual on records or in concerts, the performances themselves are almost all full-strength, unadulterated modern jazz.'

https://www.newyorker.com/culture/the-front-row/round-midnight-revisited-a-feast-of-music-and-acting