What does the file extension .MPEG stand for?

The file extension .MPEG stands for Moving Picture Experts Group.

MPEG is the name of an international standards group formed to develop methods for coding and compressing moving pictures, audio, and related multimedia data. The group was established in 1988 through cooperation between the International Organization for Standardization and the International Electrotechnical Commission. Its standards made it practical to store and transmit video using much less data than uncompressed formats required.

The name is also used for the media formats and standards produced by the group. MPEG-1 helped bring compressed video and MP3 audio to compact discs and early computers. MPEG-2 became important for DVDs, digital television, and broadcast systems. MPEG-4 later supported more advanced internet, mobile, and multimedia applications.

A common mix-up is treating MPEG as one single codec or one exact file type. It is a family of standards, and an MPEG file may use different video, audio, and container specifications. The .mpeg and .mpg extensions are closely related and commonly identify files containing MPEG-encoded audiovisual data.