Guide to MPEG-1 audio standard

This paper is designed to help the reader to unravel the ISO MPEG-1 standard for compressing digital audio data. In comparison to the standards for video, little additional information is available on this standard. The standard describes the implementation of three compression schemes called layer 1, layer 2 and layer 3. The layer 1 scheme is the simplest to implement but its efficiency is not as good as the other layers. The layer 3 scheme provides the best performance at low bit rates but it is also the most difficult one to implement. The compression techniques used psychoacoustic models for predicting the human auditory response to the noise that is introduced by the coding scheme. Using these models, the characteristics of the compression scheme can be changed dynamically in order to minimize the audibility of these noise impairments. The implementation of two such psychoacoustic models are described in the standard