DVD player
A DVD player is a device that plays discs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. These devices were invented in 1994 and continue to thrive. However, with the release of high definition media, sales and popularity are expected to drop in the upcoming years.
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[edit] Technical details
A DVD player has to complete these tasks:
- Read a DVD disc in ISO – UDF version 1.02 format
- optionally decrypt the data with either CSS and/or Macrovision
- read and obey the DVD's Regional lockout codes and display a warning if the player is not authorised to play the DVD
- decode the MPEG-2 video stream with a maximum of 10 Mbit/s (peak) or 8 Mbit/s (continuous)
- decode sound in MP2, PCM or AC-3 format and output (with optional AC-3 to stereo downmixing) on stereo connector, optical or electric digital connector
- output a video signal, either an analog one (in NTSC, PAL or SECAM format) on the composite, S-Video, SCART, or component video connectors, or a digital one on the DVI or HDMI connectors.
[edit] CD/DVD/AVI/MP4 playback
Additionally, most DVD players allow users to play audio CDs (CDDA, MP3, etc.) and Video CDs (VCD). A few include a home cinema decoder (i.e. Dolby Digital, Digital Theater Systems (DTS)). Some newer devices also play videos in the MPEG-4 ASP video compression format (such as DivX) popular in the Internet.
[edit] Portable players
Most hardware DVD players have to be connected to a television; there also exist portable devices which have an attached LCD screen and stereo speakers. Portable DVD players are often used for long road trips and other travel.
[edit] Output
Due to multiple audio (and video) output devices, a consumer has many outputs on a DVD player, and may become confused with connecting a player to a TV or amplifier. Most systems include an optional digital audio connector for this task, which is then paired with a similar input on the amplifier. The physical connection is typically RCA connectors or TOSLINK, which transmits a S/PDIF stream carrying either uncompressed digital audio (PCM) or the original compressed audio data (Dolby Digital, DTS, MPEG audio) to be decoded by the audio equipment.
[edit] Video
Video is another issue which continues to present most problems. Current players typically output analog video only, both composite video on an RCA jack as well as S-Video in the standard connector. However, neither of these connectors was intended to be used for progressive video, so yet another set of connectors has started to appear, to carry a form of component video, which keeps the three components of the video, one luminance signal and two color difference signal, as stored on the DVD itself, on fully separate wires (whereas S-Video uses two wires, uniting and degrading the two color signals, and composite uses only one, uniting and degrading all three signals). The connectors are further confused by using a number of different physical connectors on different player models, RCA or BNC, as well as using VGA cables in a non-standard way (VGA is normally analog RGB—a different, incompatible form of component video). Even worse, there are often two sets of component outputs, one carrying interlaced video, and the other progressive, or an interlaced/progressive switch (either a physical switch or a menu setting).
In Europe (but not most other PAL areas), SCART connectors are typically used, which can carry composite and analog RGB interlaced video signals (RGB can be progressive, but not all DVD players and displays support this mode) or Y/C (S-Video), as well as analog two-channel sound and automatic 4:3 or 16:9 (widescreen) switching on a single convenient multi-wire cable. The analog RGB component signal offers video quality which is superior to S-Video and identical to YPbPr component video. However, analog RGB and S-Video signals can not be carried simultaneously, due to each using the same pins for different uses, and displays often must be manually configured as to the input signal, since no switching mode exists for S-Video. (A switching mode does exist to indicate whether composite or RGB is being used.) Some DVD players and set-top boxes offer YPbPr component video signals over the wires in the SCART connector intended for RGB, though this violates the official specification and manual configuration is again necessary. (Hypothetically, unlike RGB component, YPbPr component signals and S-Video Y/C signals could both be sent over the wire simultaneously, since they share the luminance (Y) component.)
HDMI is a new digital connection for carrying high-definition video, similar to DVI. Along with video, HDMI also supports up to eight-channel digital audio. DVD players with connectors for high-definition video can upconvert the source to formats used for higher definition video (e.g., 720p, 1080i, 1080p, etc.), before outputting the signal. By no means, however, will the resulting signal be high-definition video; that is, aside from optional deinterlacing, upconverting generally consists of merely scaling the video's dimensions to match that of higher resolution formats, foregoing the scaling that would normally occur in the output device.
[edit] USB
Some DVD players include a USB video recorder.
[edit] Wireless
Wireless connections (bluetooth and/or wifi) are useful to manage (play/record) wirelessly content from or to other devices (i.e. cell phones).
[edit] Prices
As of 2005[update], retail prices for such a device, depending on its optional features (such as digital sound or video output), start between 30 and 80 USD/Euro. They are usually cheaper than VCRs.
[edit] Manufacture
As of 2002[update] the largest producer of DVD players is China; in 2002 they produced 30 million players, more than 70% of the world output. These producers have to pay US$15–$20 per player in license fees, to the patent holders of the DVD technology (Sony, Philips, Toshiba and Time Warner) as well as for MPEG-2 licenses.[1] To avoid these fees, China has developed the Enhanced Versatile Disc standard as an intended successor of DVD; as of 2004[update], EVD players were only being sold in China. It has been said in Sudan that it has the highest percentage of DVD players.
[edit] Software
Software DVD players are programs that allow users to view DVD videos on a computer with a DVD-ROM drive. Some examples are the VLC media player and MPlayer (both free software), as well as WinDVD, PowerDVD, Fluendo DVD Player and DVD Player.[2]
[edit] Successors
There are successors to the DVD player: the HD DVD player and the Blu-ray Disc player, utilizing two incompatible technologies that reproduce higher quality video images than standard DVD. On February 19, 2008, Toshiba, creator of the former technology announced it would cease production on all HD DVD products leaving Blu-ray as the high definition successor to DVD players. Also, upscaling and up-converting DVD units are available that connect to televisions via a high definition interface and increase the overall picture quality.
[edit] See also
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Wikimedia Commons has media related to: DVD players |
- CD
- CD-ROM
- Digital video recorder
- DVD Audio
- HD media player
- Recorder
- VCR
- Video scaler
- Comparison of portable media players
