Music whose source is logically located within the story space. Source music is generally inserted into a scene, making the characters and the scene aware of it.
The cultural codes that musics carry can add layers of subtextual meaning
Extra-musical Functions
Commercial functions
Concert suites
Soundtracks
Songs that enhance a film’s visibility
“The impact of the success of [Dimitri] Tiomkin’s song to High Noon on a financially strapped film industry was immediate. Producers saw in the success of Do Not Forsake Me, Oh My Darling, a means of making additional money from their films.” (Roy Prendergast)