What is a 'source cue' or 'source music'? [FAQ#12] 

    Some music in a motion picture is music IN the motion picture - an element IN or OF the scene on the screen... the music coming from the Victrola in the corner of the room or from the car radio as the characters drive down the highway; the music to which the actors are dancing in a nightclub, and so forth. This music is called 'source' music (contrast with and distinguish from a 'compilation score'). Almost every motion picture has some source music in it. But in virtually every case, music which was played during the shooting of a scene (if its played at all at the shoot) is unusable in the final product because of the impossibility of getting good sound quality on location. So source music is later either taken from its original form (say a CD or LP, if possible) or re-recorded and then 'inserted' back into the picture in the right place at the dub.

    In some instances source music can cause particular nightmares for the composer and music editor. Imagine a dance scene where the director shot and the actors moved to music from the director's favorite CD. If the studio doesn't want to pay the CD performers and/or publishers their asking price for the 'sync rights', then new music must be composed (many times in the style of the 'original' so the director maintains the feeling he had had at the filming) and performed anew. But this has to be done in such a way that this 'replacement' matches 'perfectly' the dance movements of the actors or the scene will look plain silly!