Sound in film is categorized as either diegetic or non-diegetic. Diegetic sound has a visible or implied source within the film's story, such as characters speaking or music from on-screen instruments. Non-diegetic sound comes from outside the story, including narration, added sound effects, or mood music not attributable to events on screen.

2. Sound in film is split into two different
areas; Diegetic and Non-diegetic.
Diegetic sound is sound with an on-screen
source or a source that is implied to be
present by the action of the film.
Non-diegetic is sound whose source is
neither visible on the screen nor has been
implied to be present in the action.

3. Diegetic Sound
Examples of diegetic sound within a film would be:
• sounds made by objects in the story
• voices of characters
• music represented as coming from instruments
in the film
Diegetic sound can be either on screen or off
screen depending on whatever its source is
within the frame or outside the frame.

4. Non-diegetic Sound
Examples of non-diegetic sound:
• narrator's commentary
• sound effects which is added for the dramatic
effect
• mood music
Non-diegetic sound is represented as coming
from the a source outside story space.