MPEG-2 (aka H.222/H.262 as defined by the ITU) is a standard for the generic coding of moving pictures and ISO/IEC 13818 MPEG-2 at the ISO Store. It describes a combination of lossy video compression and lossy audio data compression methods, which permit storage and transmission of movies using currently available storage media and transmission bandwidth.
This format was originally created as an alternative to mp3. The idea was to achieve a small file size with better sound quality. The first versions weren’t quite successful, but with the development of AAC, it became possible to store sound with less loss of quality, and with the same file sizes as that of mp3.