Extending MPEG-Audio Layer III to wideband speech coding

There is a gray zone between classical speech coders, working on speech signals sampled at 8 kHz, and high quality audio coders, working on audio signals sampled at 32 kHz and higher. In the last years, several systems have been proposed which fill this gray zone from both ends. These systems include wide band speech coding systems as well as high quality audio coding systems working with reduced bandwidth. This paper describes the extension of the ISO/IEC quality audio coding standard IS 11172-3 (MPEG-Audio) to lower sampling rates. The focus is on extensions of the Layer Ill of MPEG-Audio.