I have done some research on diegetic sounds and non diegetic sounds.
Here is some information I found from Filmsound.org.
Diegetic Sound:
Sound whose source is visible on the screen
or whose source is implied to be present by the action of the film:
- voices of characters
- sounds made by objects in the story
- music represented as coming from instruments
in the story space ( = source music)
Diegetic sound is any sound presented as
originated from source within the film's world
Digetic sound can be either on
screen or off screen depending on whatever its source is
within the frame or outside the frame.
Another term for diegetic sound
is actual sound
Diegesis is a Greek word
for "recounted story" The film's diegesis is the
total world of the story action
Non-Diegetic Sound:
Sound whose source is neither visible
on the screen nor has been implied to be present in the action:
- 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.
The distinction between diegetic or non-diegetic
sound depends on our understanding of the conventions of film viewing
and listening. We know of that certain sounds are represented
as coming from the story world, while others are represented as
coming from outside the space of the story events. A play with
diegetic and non-diegetic conventions can be used to create ambiguity
(horror), or to surprise the audience (comedy).
Another term for non-diegetic
sound is commentary sound.
There are a variety of sounds which will be used in our opening sequence.
The diegetic sound which will be used in our opening sequence is the conversation between characters.
There are many non-diegetic sounds which will be used in our opening sequence. First of all, during the torture scene there will be low-key music and then a voice over which will be done by myself. Then, as the opening sequence goes on and leads to the chase, the music will speed up and become quite intensified.
Another non-diegetic sound which we will add in is the gun shot.