Audio compression: Technology and applications

Recent algorithms for perceptual audio coding have provided the capability of compressing compact disk (CD)-stereo audio material (at 1,406 kbits/s) into rates approximating 128 kbits/s. This capability has enabled the development of several new classes of applications in audio transmission, broadcasting, and storage. In exploring the opportunities provided by these applications, rapid progress is occurring in three related technologies: signal processing and computing, for the creation of inexpensive audio decoders; communication techniques, for reliable transmission of compressed audio over radio channels; and, advanced memory, to supplement or replace the magnetic and optical media currently used to store high-quality audio. Perceptual audio coding will also enable the delivery of AM to FM-grade audio signals over voice-band modems at rates of about 32 kbits/s.