The MP4 file extension is mainly used for the MPEG-4 multimedia file format. The MP4 format is an add-on plugin for MPEG-4, which is a standard for storing encoded multimedia content (audio files, video content, subtitles, images, and metadata, etc.). Some versions of the format have encryption and copy protection (DRM) capabilities. The disadvantages of the mpeg4 format include the lower video and sound quality compared to the DVD format. MP4 is based on Apple's QuickTime format and contains various types of name extensions (mp4, m4a, m4p).