MPEG is an acronym for the Moving Picture Experts Group. This committee is responsible for developing international standards for compression in motion picture and studio applications. One such standard is MPEG-1 Layer-3, commonly referred to as MP3.

MP3 is a technique used to compress audio signals by a factor of about 12. The compression process is based upon limitations of the human ear. For example, sounds that immediately follow a sudden loud musical passage tend to be masked by the loud sound. Also, the ear has difficulty in distinguishing closely spaced tones. MP3 processing eliminates those sounds that the ear cannot hear or has difficulty hearing. The result is a smaller or compressed digital package that can be easily sent over the Internet or recorded.

IEEE Spectrum, September 2004