Refers to a group of perceptual coding standards agreed upon by MPEG (Motion Picture Coding Experts Group) and used to encode or compress, audio and video sources in a fashion that reduces the amount of data required to represent them with (hopefully) minimal degradation in perceived quality. MPEG-2, which first came out around 1994, built upon the achievements of MPEG-1 and included such improvements as the ability to encode interlaced video and multi-channel audio such as AC-3 and AAC, as well as providing better methods for keeping video in tact when data integrity is not entirely reliable. MPEG-2 is the current standard for broadcasting digital video signals and DVD production. And with a few enhancements it is also used for broadcasting High Definition television signals.