Perceptual audio coding

Audio Coding has proliferated as a mainstream enabling digital technology for all types of applications that provide audio and multimedia to consumers using transmission or storage channels with limited capacity. Since its infancies in the eighties and early nineties, the technology behind low bitrate audio coding has developed rapidly until today. Nonetheless, the technology generations seen to date follow several common themes, including the use of time/frequency-domain processing, redundancy reduction (entropy coding), and irrelevancy removal through the pronounced exploitation of perceptual effects. The latter aspect is of paramount importance to the understanding and the performance of the coding systems and has gained more and more in importance over time. Starting from basic principles, this article provides an overview of methods for low bitrate perceptual audio coding and its evolution over time along with some related coding standards (e.g. 'mp3') and typical applications.