A standard for a group of audio and video coding formats. MP4 was introduced in late 1998 and agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) under the formal standard ISO/IEC 14496. Uses of MP4 include compression of audio and visual data for the Web (streaming media) and CD distribution, voice (telephone, videophone) and broadcast television applications.
Technically, MPEG-4 is a patented collection of methods defining compression of audio and visual (AV) digital data. It was designed to encompass all the features that were part of earlier releases of MPEG files, and add a few more features including (extended) VRML support for 3D rendering, object-oriented composite files (including audio, video and VRML objects), support for externally-specified Digital Rights Management and various types of interactivity.
So great was the success of MP4 that by 1999, it was considered the standard for all types of streaming and broadcast applications online. The functionality of the format was such that programmers were able to easily make use of MP4 on Web sites and in various other applications. Businesses found it to be a great sales and marketing tool, and users had a great time viewing, swapping, and even creating their own streaming media in the MP4 format.