Web Design in a Nutshell, 3rd Edition

MPEG compression

The MP3s that we’ve grown to love are technically MPEG-1, Layer-III files. MPEG is actually a family of multimedia standards created by the Moving Picture Experts Group. It supports three types of information: video, audio, and streaming (which, in the context of MPEG compression, is synchronized video and audio).

MPEG uses a lossy compression scheme that is based on human auditory perception. Sounds that are not discernible to the human ear are thrown out in the compression process. The resulting file sounds nearly the same, but contains much less data than the original.

There are a number of MPEG standards: MPEG-1 was originally developed for video transfer at VHS quality and is the format used for MP3s; MPEG-2 is a higher-quality standard that was developed for television broadcast; other MPEG specs that address other needs (such as MPEG-7) are currently in development. MPEGs can be compressed using one of three schemes: Layer-I, -II, or -III (the “3” in MP3 refers to its compression scheme layer). To learn more about MPEG, visit the MPEG web site (http://www.mpeg.org).