Universal Media Disc
|Media type||Optical disc|
|Capacity||900 MB (single layer), 1.8 GB (dual layer)|
|Usage||Games, movies, music|
The Universal Media Disc (UMD) is an optical disc medium developed by Sony for use on their PlayStation Portable handheld gaming and multimedia platform. It can hold up to 1.8 gigabytes of data and is capable of housing video games, feature-length films, and music. UMD is the trademark of Sony Computer Entertainment Inc. for their optical disk cartridge (ODC).
- Dimensions: approx. 64 mm (diameter) × 4.2 mm (thickness)
- Maximum capacity: 1.80 GB (dual layer), 900 MB (single-layer)
- Laser wavelength: 660 nm (red laser)
- Encryption: AES 128-bit
Video storage format 
While the primary application for UMD discs is as a storage medium for PSP games, the format is also 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. Video stored on UMD is typically encoded in 720×480 resolution, but is scaled down when displayed on the PSP.
Region coding 
- Region 0: Worldwide
- Region 1: United States, Canada, U.S. territories, Latin America
- Region 2: European Union, Japan, Middle East, Egypt, South Africa, Greenland, French territories
- Region 3: Thailand, Singapore, Malaysia, Taiwan, South Korea, Philippines, Indonesia, Hong Kong
- Region 4: Australia, New Zealand, Pacific Islands, Latin America
- Region 5: Russia, Eastern Europe, India, Pakistan, the majority of Africa, North Korea, Mongolia
- Region 6: Mainland China
Despite the fact that the UMD format is proprietary and its specifications are not publicly available, a combination of software security flaws in early PlayStation Portable firmware builds made it possible to extract images of discs in the standard ISO 9660 format. Sony had included methods for loading game images from other storage mediums as a means of future proofing the PSP. This has been exploited to allow full retail UMD images to be run, making it possible to run copied UMD images with no hardware modifications.
UMDs offer large capacity and the capability to store quality audio/video content; however, the format's proprietary nature and the lack of writers and blank media has made adoption difficult. In comparison to Sony's MiniDisc format, there are a number of features lacking; the sliding shield which prevents direct disc contact on MiniDiscs is absent from all UMDs released, though it is an option according to the ECMA specification. PSPs were also not made compatible with MiniDiscs.
According to the official ECMA specification Sony designed the UMD to support two possible future enhancements and products.
- Protective Shutter: Similar to the MiniDisc and 3.5 in floppy disc, this protective shutter will shield the inner disc from accidental contact.
- Auto-Loading: UMDs were designed for possible future slot loading devices with Auto-Loading mechanisms. These would be very similar to the auto-loading mechanism used in slot loading MiniDisc home and car decks. It would also be similar to the VHS U-Matic auto-loading mechanism. Unlike the current clamshell loading design the PSP uses, a slot loading device using an Auto-Loading mechanism would be motorized and completely automatic. The user would insert the disc into the device slot, the motorized mechanism would then take over and draw the disc inside the drive completing the loading process. The disc would also be ejected fully automatically by the motorized mechanism, like a VCR. This would also mean that power would be required in order to insert or eject a disc.
Availability and support 
The UMD format never saw implementation on any device other than the PlayStation Portable, and as a result the market is very limited compared to those for other optical media formats. Buyers were generally put off by the high price of UMD releases, which often retailed at comparable prices to but lacked the extra content found on DVDs. Poor sales of UMD movies early in the format's life had caused major studios Universal and Paramount to rescind their support. Retail support of the format experienced similar troubles, and in 2006 Wal-Mart began phasing out shelf space devoted to UMD movies, with other chains soon following suit. Today, most non-specialty retail stores have stopped bringing in new UMD movies and no longer have a separate section devoted to them, with a few stray unsold titles mixed in amongst the regular PSP games. Sony Pictures, Columbia, and other film publishers continue to distribute their films on UMD in a limited capacity. Capcom, HBO, Disney and various other content producers have also continued their support of the format, releasing TV shows, cartoons and OVAs on UMD as well.
In August 2007, Multimedia Recovery brought to the market their UMD Replacement Case after many complaints from PlayStation Portable owners that the outer casing of the UMD disc was cracking or pulling apart due to the poor design, which causes the UMD to become unreadable in the PlayStation Portable.
In late 2009, Sony began pushing developers away from the UMD format and towards digital distribution on the PlayStation Network in preparation for the launch of the digital-download-only PSP Go, which is the first PSP model to not include a UMD drive. However, the new system has experienced lackluster sales compared to previous models, with most consumers still choosing the UMD-compatible PSP-3000 model, which continues to be sold alongside the PSP Go. Despite the earlier push for PlayStation Network releases around the PSP Go's launch, over half of the PSP's library is still only available in UMD format including Crisis Core: Final Fantasy VII and Kingdom Hearts Birth by Sleep, though there have been a few PlayStation Network-only releases since the PSP Go's launch, such as LocoRoco Midnight Carnival. Still, most new games continue to be distributed via UMD, and, aside from those published by SCE, not all have been released on PlayStation Network. In 2011, the PSP-E1000, a budget PSP model with a UMD slot but without Wi-Fi (and thus no internet connectivity), was released.
The successor of the PlayStation Portable, the PlayStation Vita, dropped UMD support entirely in a move similar to the PSP Go, focusing instead on digital downloads and opting for low-profile flash-based media for its retail software.
See also 
- Ecma International (June 2005). "Data Interchange on 60 mm Read-Only ODC—Capacity: 0,8 Gbytes (UMD)" (PDF).
- "PSP procures porn in Japan". GameSpot.com. June 2, 2005. Retrieved 2007-07-20.
- Arnold, Thomas K. (2006-03-30). "UMD losing H'wood game". The Hollywood Reporter. Retrieved 2010-02-11.[dead link]
- Erickson, Kris (2008-08-15). "Sony Continues to Support UMD Format with New Pricing". GameFlavor. Retrieved 2010-02-11.
- "Wal-Mart to cease UMD movie sale". QJ.NET. 2006-03-30. Retrieved 2010-02-11.
- "Sony PSP2 Rumors Bogus". The Business Insider. December 17, 2008. Retrieved 2009-10-27.
- Moses, Asher (2009-10-20). "PSP Go a no-go as Sony struggles for sales". Fairfax Digital. Retrieved 2010-02-11.
- Gantayat, Anoop (2009-11-02). "Enterbrain Shares PSP go First Day Sales". andriasang.com. Retrieved 2010-02-11.
|Wikimedia Commons has media related to: Universal Media Disc|
- The Digital Bits Guide to UMD Movies including a list of movies available on UMD
- UMD Talk contains UMD articles, news, resources & technical details.
- Sony PSP Movie Sales Strong Article on the early success of movie sales on UMD from MP3 Newswire
- Breaking news: Sony's UMDs aren't selling well News story about the disappointing UMD sales.
- UMD Movie Database
- Multimedia Recovery Multimedia Recovery's website for the UMD Replacement Case