Why are there background noises in the sound of moving pictures or sound that recorded in a car?

Why are there background noises in the sound of moving pictures or sound that recorded in a car?

Select [Recording] on [Volume Control Properties] to set the level of the microphone a little lower.
The internal microphone is a non-directional microphone. Therefore, it also records noises around you. In addition, the input level of the microphone is set a little higher

To improve the situation, on [Volume Control], select [Option]->[Property] and select [Adjust volume for]->[Recording]. Then, set the sound volume of the microphone a little lower.
This makes the level of conversation volume lower with the background noise reduced fairly.

[Remark]
The level of noise varies from one person to another.
Since the driving noise cannot be eliminated totally, noises contained in the sound cannot be removed completely.
In addition, not only in a moving car, if there is any noise around you, the sound may contain noises as well.