Friday, August 24, 2007

DVD (also known as "Digital Versatile Disc" or "Digital Video Disc") is a popular optical disc storage media format used for data storage. Primarily uses are for movies, software, and data backup purposes, DVDs are of the same form factor as compact discs (CDs), but allow for 8 times the data storage capacity (single-layer, single-sided).
All read-only DVD discs, regardless of type, are DVD-ROM discs. This includes replicated (factory pressed), recorded (burned), video, audio, and data DVDs. A DVD with properly formatted and structured video content is a DVD-Video disc. DVDs with properly formatted and structured audio content are DVD-Audio discs. Everything else, (including other types of DVD discs with video content) is referred to as a DVD-Data disc. Consumers use the term "DVD-ROM" to refer to pressed data discs only, but that is incorrect usage; moreover, the term DVD is also applied generically in describing newer video disc formats, Blu-ray Disc and HD DVD.

Optical disc
Optical disc image
Recorder hardware
Authoring software
Recording technologies

  • Recording modes
    Packet writing
    Compact Disc/CD-ROM: CD-R, CD-RW
    Blu-ray Disc: BD-R, BD-RE
    Holographic data storage
    3D optical data storage
    History of optical storage media
    Rainbow Books
    File systems

    • ISO 9660

      • Joliet
        Rock Ridge

        • Amiga Rock Ridge extensions
          El Torito
          Apple ISO9660 Extensions
          Universal Disk Format

          • Mount Rainier DVD-ROM History
            "DVD" was originally used as an initialism for the unofficial term "digital videodisk". The official DVD specification documents have never defined DVD. Usage in the present day varies, with "DVD", "Digital Video Disc", and "Digital Versatile Disc" all being common.

            The 12cm type is a standard DVD, and the 8cm variety is known as a mini-DVD. These are the same sizes as a standard CD and a mini-CD, respectively.
            Note: GB here means gigabyte, equal to 10 (or 1,073,741,824) bytes.
            Example: A disc with 8.5 GB capacity is equivalent to: (8.5 × 1,000,000,000) / 1,073,741,824 ≈ 7.92 GiB.
            Size Note: There is a difference in size between + and - DL DVD formats. For example, the 12 cm single sided disk has capacities:

            Capacity nomenclature
            DVD uses 650 nm wavelength laser diode light as opposed to 780 nm for CD. This permits a smaller spot on the media surface that is 1.32 µm for DVD while it was 2.11 µm for CD.
            Writing speeds for DVD were 1x, that is 1350 kB/s (≈1.32 MiB/s), in first drives and media models. More recent models at 18x or 20x will have 18 or 20 times that speed. Note that for CD drives, 1x means 153.6 kB/s (150 KiB/s), 9 times slower. DVD FAQ

            DVD-ROM Technology
            Main article: DVD recordable
            HP initially developed recordable DVD media from the need to store data for back-up and transport.
            DVD recordables are now also used for consumer audio and video recording. Three formats were developed: -R/RW (minus/dash), +R/RW (plus), -RAM (which is strictly speaking not random access memory).

            DVD recordable and rewriteable
            Dual Layer recording allows DVD-R and DVD+R discs to store significantly more data, up to 8.5 Gigabytes per disc, compared with 4.7 Gigabytes for single-layer discs. DVD-R DL was developed for the DVD Forum by Pioneer Corporation, DVD+R DL was developed for the DVD+RW Alliance by Philips and Mitsubishi Kagaku Media (MKM). Many current DVD recorders support dual-layer technology, and the price is comparable to that of single-layer drives, though the blank media remain significantly more expensive.

            Dual layer recording

            Main article: DVD-Video DVD-Video

            Main article: DVD-Audio DVD-Audio

            Main article: CPRM Security
            There are several possible successors to DVD being developed by different consortiums: Sony/Panasonic's Blu-ray Disc (BD), Toshiba's HD DVD and Maxell's Holographic Versatile Disc (HVD).
            In April 2000, Sonic Solutions and Ravisent announced hDVD, an HDTV extension to DVD that presaged the HD formats that debuted 6 years later.
            On April 15, 2004, in a co-op project with TOPPAN Printing Co., the electronics giant Sony Corp. successfully developed the paper disc, a storage medium that is made out of 51% paper and offers up to 25 GB of storage, about five times more than the standard 4.7 GB DVD. The disc can be easily cut with scissors and recycled offering an environmentally friendly storage medium.
            As reported in a mid 2005 issue of Popular Mechanics, it is not yet clear which technology will win the format war over DVD. HD DVD discs have a lower capacity than Blu-ray Discs (15 GB vs. 25 GB for single layer, 30 GB vs. 50 GB for dual layer). Other speculations as to which format will win include Blu-ray Disc's larger hardware vendor and movie studio support, and HD DVD's faster read times.
            This situation—multiple new formats fighting as the successor to a format approaching purported obsolescence—previously appeared as the "war of the speeds" in the record industry of the 1950s. It is also similar to the VHS/Betamax war in consumer video recorders in the late 1980s.
            The new generations of optical formats have restricted access through many various digital rights management schemes such as AACS and HDCP; it remains to be seen what impact the limitation of fair use rights has on their adoption in the marketplace.

            Competitors and successors

            CD and DVD packaging
            DIVX disposable DVD
            DVD authoring
            DVD cover art
            DVD Formats
            DVD Talk
            DVD TV Games
            DVD-D disposable DVD
            Enhanced Versatile Disc
            Super Audio CD
            User operation prohibition
            Flexplay disposable DVD
            HD DVD
            Blu-ray Disc
            Inkjet printable DVD
            List of DVD manufacturers
            MultiLevel Recording
            Special edition
            DVD-RAM Official

            Dual Layer Explained – Informational Guide to the Dual Layer Recording Process

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