Sound

In any film sound is majorly important. There are two types of sound: digetic and non digetic.

Digetic Sound

digetic sound refers to sound that you would typically hear within the world of narrative. Examples of digetic sound are dialogue, sound effects and music. However music is only digetic sound when it comes from a source within the scene; the source of the music doesn't have to be visible but it has to be expected to be used where it is heard (for example if a scene is filmed in a club/bar the source of the music may not be visible but hearing music in that setting is a norm).

Non Digetic Sound

Non digetic sound refers to sound that are not heard within film; basically everything outside the world of narrative. Examples of digetic sound are voice overs, captions, titles/subtitles and soundtracks.

As well as there being Digetic and non digetic there is also onscreen and off screen sound.

Onscreen And Off screen Sound

Onscreen sound is sound that is relative to what is shown in the shot e.g a telephone ringing where as off screen sound is sound that has no relation to what is happening in the shot. The most common use of off screen sound is music.

Parallel

Parallel sound is when the sound matches the action.

Contrapuntal

Contrapuntal sound is when the sound does not match the action.

Sound Bridge

A sound bridge helps create a smooth transition between two different scenes.