Score: A Film Music Documentary (2016) was written and directed by Matt Schrader. The film featured dozens of people who have written, directed, and played music for movies. These included Hans Zimmer and Danny Elfman, but there were many, many more.
Often, we don't even notice the music playing during a film. Or else we somehow believe that the music just arrived in the movie. There it is--we listen or not depending on how loud it is or how beautiful it is.
Of course, some film music has become popular in its own right. Figure skaters still perform to Tara's Theme, or the 007 theme, or the music from Dr. Zhivago, years after the films have somewhat faded from our mind.
Still, cinema is a visual medium, and we don't think much about the music when we're watching the movie. The music is "just there." Except that it isn't. Score documents the immense effort and cost involved in bringing music into the films.
I recommend this movie because I think that you'll learn quite a bit, as I did. Also, the film made me more conscious of the music we hear every time we go to the movies, or watch a film on the small screen. Also, it will work very well on the small screen.