MPEG

MPEG (named for the Moving Picture Experts Group) is a series of compression standards for digital video and audio file formats. It's mostly associated with video compression but also includes MP3 audio (MPEG-1 Audio Layer 3).

MPEG-1 (first generation first used for video-CDs and includes the MP3 audio format)
MPEG-2 (used for broadcast TV, satellite, over-the-air digital TV, and standard DVD)
MPEG-3 (abandoned, not the same as MP3)
MPEG-4 (used for HD-DVD, Blu-ray disc® formats)