A film score (also sometimes called background score, background music, film music or incidental music) is original music written specifically to accompany a film. The score forms part of the film's soundtrack, which also usually includes dialogue and sound effects, and comprises a number of orchestral, instrumental, or choral pieces called cues, which are timed to begin and end at specific points during the film in order to enhance the dramatic narrative and the emotional impact of the scene in question. Scores are written by one or more composers, under the guidance of, or in collaboration with, the film's director or producer and are then usually performed by an ensemble of musicians – most often comprising an orchestra or band, instrumental soloists, and choir or vocalists – and recorded by a sound engineer.