MPEG-1 Layer III Standard: A Simplified Theoretical Review

MP3 is a standard that is used for encoding/decoding audio data. The standard can lower audio bit rate significantly without any loss. For this reason, it is key to understand how it does so, and secondly, find out if it is doable. Raw audio signals carry large data quantities and are neither suitable for transmission nor storage [2]. Therefore it is necessary to compress audio and at the same time maintain its quality as required by the International Organization for Standardization (ISO). MP3 was developed by the Motion Pictures Experts Group for audio and video compression. It is composed of three modes; the third referred to as Layer III. It is this layer that lowers raw-audio data bit rates from i.e. 1.4 Megabits per second to just 128 kilobits per second and can still reconstruct the signals to a level comparable to the original [3]. The objective of this paper is to review and provide a simple idea of what Layer III does in relations to audio compression and decompression.