MPEG-1

http://www.tnt.uni-hannover.de/project/mpeg/audio/faq/mpeg1.html

This is the official FAQ from the MPEG Audio Subgroup, maintained by Heiko Purnhagen. As the others FAQs from that site, it gives an excellent overview on this first audio compression standard - so print it, read it... ;-)

See also MPEG.