MPEG-4, like the MPEG-1 and MPEG-2 standards, codifies methods for encoding audio and video while optimizing media fidelity and reducing file size as much as possible. It includes features for 3D rendering with VRML (Virtual Reality Modeling Language), DRM (digital rights management) support, and various forms of interactivity. Codecs and technologies which use the MPEG-4 standard include DivX, Xvid, QuickTime, DVDs, and Blu-ray discs.
Audiobooks and podcasts often use the MP4 format, as do ringtones on the iPhone. Other mobile phones use a variation of the MP4 format, called 3GP.
Example of an MPEG-4 or MP4 video
In the example above, we're using the HTML5 <video> tag to embed an MP4 video into this web page.