Let's say music is needed for only 43 seconds of film. You have to score it so it is an entity, so it won't bother anyone when it ends so quickly. Or if a song runs 2 minutes and 45 seconds, but the titles run a minute longer, you have to arrange that song so it doesn't get repetitious.
Marvin HamlischMy whole thing is not just to play music for people, but to make them part of the evening.
Marvin Hamlisch