The Universal Media Disc (UMD) is an optical disc medium developed by Sony for use on the PlayStation Portable. It can hold up to 1.8 gigabytes of data, which can include games, movies, music, or a combination of these. It is considered the first optical disc format to be used for a handheld video game system.
The primary application for UMD discs is as a storage medium for PSP games, although the format is also being used for the storage of motion pictures, and to a lesser degree, television shows for playback on the PSP. The video is encoded in the H.264/MPEG-4 AVC format, with the audio in ATRAC3plus.
The BBC began releasing a number of its TV titles on UMD in the UK, including The Office, Doctor Who and Little Britain.
Some adult films have been released on UMD in Japan.[2] Sony does not officially approve of such content, however, the enormous market in Japan for these releases is supporting the PSP's sales. Sony has thus refrained from taking action.