Masking

Masking is based on masking properties of the human ear. In contrast: When you look at the sun and if a bird passes ahead, you do not see it because of the too predominant light of the sun. In audio, it is similar. During strong sounds, you do not hear the weakest sounds. Take as an example a piece of organ: When the organist does not play, you hear the breath in the piping, and when he plays, you no longer hear it because it is masked.

It is therefore not necessary to code all the sounds. This is the first property used by the MP3 format to earn some space. For this the mp3 encoder uses a psychoacoustic model modeling the behavior of the human ear.