Film music is the residue of a film score. It is merely the tangeable version of a film score. What's important to remember is that a master film composer is writing this "music" to a film. They are scoring notes on sheet paper to connect visual emotions with the vibrance and resonance of sound, often music. So, the essence really of a film score has nothing to do with the music, but rather the element that comes out when it is connected with the image.

In some cases the "score" may be sound concréte (based on natural sounds). Even more so, if you take that element away from the film it's inherent will and force is lost, especially if you have not previously experienced the visual connection. You may be able to construe your own connections with your own imaginings, evoking wonderous and furous thoughts, creating an enjoyable experience and like toward the recording, and that might be pleasureable to the ego of the original composer. But nothing will please the composer more than the reflections you express dealing with the element of combination or lack of combination (Bullitt chase scene) between the emoting of his work and the emoting of the film's mechanics (Actors, Visuals, etc.).

Often is the case where a composer experiments with, or even bases his entire style upon, creating a score that works in it's heightened state with film, and simultaneously as solely a listening experience, and even in some cases as stand alone concert works (Magnificent Seven, Altered State) where no one might ever know their link to the art of film. Some composers have been akin to working out a concert version or medley of a score, reshaping the structure and development so that it will fit a concert goers and fellow composers ear.

And in some bold moves, filmmakers are transcending the embodiement of the composer, and "scoring" their films quite intelligently with concert works (Stanley Kubrick, Spike Lee). The results are startling, and always shake things up a bit in the film scoring field. But it is anyone's right to use the power of film scoring. You needn't be a musician, and I may be so bold as to say, you needn't be musical to use it's power. You just need to be able to understand what it is. Film Scoring not film music.