The Moving Picture Experts Group (MPEG) is a working group of authorities that was formed by ISO and IEC to set standards for audio and video compression and transmission. It was established in 1988 for the development of new video coding recommendations and to set international standards for Advanced Video Coding. MPEG is a collection of methods defining compression of audio and visual (AV) digital data. It was designated a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) under the formal standard ISO/IEC 14496. MPEG-4 is the version of the standard that addresses compression of AV data for web (streaming media) and CD distribution, voice (telephone, videophone) and broadcast television applications.

This SonicWALL signature identifies legitimate download of MPEG-4 mime-types.