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{{Short description|Standard for transmitting digital video to a display}}
{{Redirect|DVI}}
{{More citations needed|date=May 2023}}
{{Infobox connector
|name=Digital Visual Interface (DVI)
|type=Digital
|logo= [[File:
|image=
|caption=A [[Gender of connectors and fasteners|male]] DVI-D (single link) connector
|designer=[[Digital Display Working Group]]
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|width=
|height=
|video_signal=Digital video stream:<br />Single link: {{resx|1920 × 1200}} ([[WUXGA]])
|data_bit_width=
|data_bandwidth=(Single link) 3.96 Gbit/s <br />(Dual link) 7.92 Gbit/s
|data_devices=1
|data_style=3 × [[Transition Minimized Differential Signaling|transition minimized differential signaling]] data and clock
|cable=
|physical_connector=
|num_pins=DVI-D Single Link: 19<br />DVI-D Dual Link: 25<br />DVI-I Single Link: 23<br />DVI-I Dual Link: 29<br />DVI-A: 11<br />DVI-M1-DA: 35
|pinout_image=[[File:DVI Connector Pinout.svg|300px]]
|pinout_caption=A female DVI-I socket from the front
|pinout_image2=[[File:DVI pinout no info.
|pinout_caption2=Color coded (click to read text)
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}}
'''Digital Visual Interface''' ('''DVI''') is a [[video display interface]] developed by the [[Digital Display Working Group]] (DDWG).
==History==
An earlier attempt to promulgate an updated standard to the analog [[VGA connector]] was made by the [[Video Electronics Standards Association]] (VESA) in 1994 and 1995, with the [[VESA Enhanced Video Connector|Enhanced Video Connector]] (EVC), which was intended to consolidate cables between the computer and monitor.<ref name=VESA-stds>{{cite web |url=http://www.vesa.org:80/standards.html |title=VESA Standards |publisher=Video Electronics Standards Association |archive-url=https://web.archive.org/web/19990117080256/http://www.vesa.org:80/standards.html |archive-date=January 17, 1999 |url-status=dead}}</ref><ref name=Manchester99>{{cite report |first=Gary |last=Manchester |date=1999 |archive-url=https://web.archive.org/web/20160112151649/http://www.tu-chemnitz.de/informatik/RA/news/stack/kompendium/vortraege_99/peripherie/standards/dfp/DFPwhitepap.PDF |title=The VESA Digital Flat Panel (DFP) Standard: A White Paper |publisher=VESA Marketing Committee |url=http://www.tu-chemnitz.de/informatik/RA/news/stack/kompendium/vortraege_99/peripherie/standards/dfp/DFPwhitepap.PDF |archive-date=January 12, 2016 |url-status=dead}}</ref> EVC used a 35-pin [[Molex]] MicroCross connector and carried analog video (input and output), analog stereo audio (input and output), and data (via [[USB]] and [[FireWire]]). At the same time, with the increasing availability of digital flat-panel displays, the priority shifted to digital video transmission, which would remove the extra analog/digital conversion steps required for VGA and EVC;<ref name=DVI-whitepaper/>{{rp|5–6}} the EVC connector was reused by VESA,<ref>{{cite web |url=http://www.vesa.org:80/public/Intellectual%20Property/MolexPnD.PDF |title=Molex PnD intellectual property letter |author=Manchester, Gary |date=October 7, 1996 |archive-url=https://web.archive.org/web/20030222125034/http://www.vesa.org:80/public/Intellectual%20Property/MolexPnD.PDF |archive-date=February 22, 2003 |url-status=dead}}</ref> which released the [[VESA Plug and Display| Plug & Display (P&D)]] standard in 1997.<ref name=VESA-stds/> P&D offered single-link [[Transition-minimized differential signaling|TMDS]] digital video with, as an option, analog video output and data (USB and FireWire), using a 35-pin MicroCross connector similar to EVC; the analog audio and video input lines from EVC were repurposed to carry digital video for P&D.<ref name=DVI-whitepaper/>{{rp|4}}<ref name=VESA-P&D>{{cite web |url=http://www.vesa.org/public/PnD/pnd.pdf |archive-url=https://web.archive.org/web/20030704041337/http://www.vesa.org/public/PnD/pnd.pdf |archive-date=July 4, 2003 |url-status=dead |date=June 11, 1997 |title=VESA Plug and Display (P&D) Standard, Version 1 |publisher=Video Electronics Standards Association}}</ref>{{rp|§1.3.3}}
Because P&D was a physically large, expensive connector, a consortium of companies developed the DFP standard (1999), which was focused solely on digital video transmission using a 20-pin [[micro ribbon connector]] and omitted the analog video and data capabilities of P&D.<ref name=Manchester99/>{{rp|3}}<ref name=DVI-whitepaper>{{cite report |url=https://www.fpga4fun.com/files/WP_TMDS.pdf |title=Digital Visual Interface & TMDS Extensions |date=October 2004 |publisher=Silicon Image |access-date=31 January 2023}}</ref>{{rp|4}} DVI instead chose to strip just the data functions from P&D, using a 29-pin MicroCross connector to carry digital and analog video.<ref>{{cite web |url=https://www.molex.com/mx_upload/family/microcross_dvi/082mcdvi.pdf |title=MicroCross DVI Connector System: Digital Visual Interface Standard |publisher=Molex |date=December 2000 |access-date=31 January 2023}}</ref> Critically, DVI allows dual-link TMDS signals,<ref>{{cite web |url=https://www.mouser.com/datasheet/2/276/2/molex_dvi%20technical1-1185865.pdf |title=MicroCross DVI (Digital Visual Interface) Connector System |publisher=Molex |date=November 1999 |access-date=31 January 2023}}</ref> meaning it supports higher resolutions than the single-link P&D and DFP connectors, which led to its successful adoption as an industry standard. Compatibility of DVI with P&D and DFP is accomplished typically through passive adapters that provide appropriate physical interfaces, as all three standards use the same DDC/EDID handshaking protocols and TMDS digital video signals.<ref name=DVI1.0 >{{cite web |url=
DVI made its way into products starting in 1999. One of the first DVI monitors was [[Apple Inc.|Apple's]] original [[Apple Cinema Display|Cinema Display]], which launched in 1999.
==Technical overview==
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===TMDS===
Digital video [[pixel]] data is transported using multiple TMDS [[
====Single link====
A ''single link'' DVI connection has four TMDS pairs. Three data pairs carry their designated 8-bit RGB component (red, green, or blue) of the video signal for a total of 24 bits per [[pixel]]. The fourth pair carries the TMDS clock. The binary data is encoded using [[8b/10b encoding]]. DVI does not use [[packet (information technology)|packetization]], but rather transmits the pixel data as if it were a [[rasterized]] analog video signal. As such, the complete frame is ''drawn'' during each vertical refresh period.
====Dual link====
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===DDC===
Like modern analog [[VGA connector]]s, the DVI connector includes pins for the [[display data channel]] (DDC), which allows the graphics adapter to read the monitor's [[extended display identification data]] (EDID). When a source and display using the DDC2 revision are connected, the source first queries the display's capabilities by reading the monitor EDID block over an [[Inter-Integrated Circuit|I²C]] link.
===Cable length===
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==Connector==
{{see also|Mini-DVI|Micro-DVI}}
{{Multiple image
| image1 = DVI Connector Types.svg
| direction = vertical
| total_width =
| image2 = M1-DA.svg
| caption2 = Female DVI connector pins (view of plug)
}}
The DVI connector on a device is given one of three names, depending on which signals it implements:
*''DVI-I'' (integrated, combines digital and analog in the same connector; digital may be single or dual link)
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*''DVI-A'' (analog only)
Most DVI connector types—the exception is DVI-A—have pins that pass digital video signals. These come in two varieties: single link and dual link. Single link DVI employs a single transmitter with a TMDS clock up to 165 MHz that supports resolutions up to 1920 × 1200 at 60 Hz. Dual link DVI adds six pins, at the center of the connector, for a second transmitter increasing the bandwidth and supporting resolutions up to 2560 × 1600 at 60 Hz.<ref>{{cite web|url=http://www.anandtech.com/show/2184/2|archive-url=https://web.archive.org/web/20100520033457/http://www.anandtech.com/show/2184/2|url-status=dead|archive-date=May 20, 2010|title=Dell 2407WFP and 3007WFP LCD Comparison|last=Walton|first=Jarred|date=March 2, 2007|publisher=AnandTech|access-date=November 7, 2013}}</ref> A connector with these additional pins is sometimes referred to as DVI-DL (dual link). Dual link should not be confused with ''[[Multi-monitor|dual display]]'' (also known as ''dual head''), which is a configuration consisting of a single computer connected to two monitors, sometimes using a [[DMS-59]] connector for two single link DVI connections.
In addition to digital, some DVI connectors also have pins that pass an analog signal, which can be used to connect an analog monitor. The analog pins are the four that surround the flat blade on a DVI-I or DVI-A connector. A [[Video Graphics Array|VGA]] monitor, for example, can be connected to a video source with DVI-I through the use of a passive adapter. Since the analog pins are directly compatible with VGA signaling, passive adapters are simple and cheap to produce, providing a cost-effective solution to support VGA on DVI. The long flat pin on a DVI-I connector is wider than the same pin on a DVI-D connector, so even if the four analog pins were manually removed, it still wouldn't be possible to connect a male DVI-I to a female DVI-D. It is possible, however, to join a male DVI-D connector with a female DVI-I connector.<ref name="A+ Study Guide book">{{cite book|last1=Docter|first1=Quentin|last2=Dulaney|first2=Emmett|last3=Skandier|first3=Toby|title=CompTIA A+ Complete Deluxe Study Guide: Exams 220-801 and 220-802|year=2012|publisher=John Wiley & Sons, Inc.|___location=Indianapolis, Indiana|isbn=978-1118324066}}</ref>
DVI is the only widespread video standard that includes analog and digital transmission in the same connector.<ref>{{cite book |last=Kruegle |first=Herman |title=CCTV Surveillance: Analog and Digital Video Practices And Technology |publisher=Butterworth-Heinemann |isbn=0-7506-7768-6 |page=268 |chapter=8 |chapter-url=https://books.google.com/books?id=DaQY8CrmqFcC&q=DVI+is+the+only+widespread+video+standard+that+includes+analog+and+digital+transmission+options+in+the+same+connector.&pg=PA268 |year=2006 }}</ref>
Some [[DVD player]]s, [[High-definition television|HDTV]] sets, and [[video projector]]s have DVI connectors that transmit an encrypted signal for copy protection using the [[High-bandwidth Digital Content Protection]] (HDCP) protocol. Computers can be connected to HDTV sets over DVI, but the graphics card must support HDCP to play content protected by [[digital rights management]] (DRM).
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** [[WQUXGA]] ({{resx|3840|2400}}) @ 30 Hz with CVT-RB blanking (2 pixels per 146 MHz TMDS clock)
[[Generalized Timing Formula]] (GTF) is a [[VESA]] standard which can easily be calculated with the [[Linux]] gtf utility.
====Digital data encoding====
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Like other ways of transmitting video, there are two different regions: the active region, where pixel data is sent, and the control region, where synchronization signals are sent. The active region is encoded using [[transition-minimized differential signaling]], where the control region is encoded with a fixed [[8b/10b encoding]]. As the two schemes yield different 10-bit symbols, a receiver can fully differentiate between active and control regions.
When DVI was designed, most computer monitors were still of the [[cathode
[[High-bandwidth Digital Content Protection|HDCP]] is an extra layer that transforms the 10-bit symbols before transmitting. Only after correct authorization can the receiver undo the HDCP encryption. Control regions are not encrypted in order to let the receiver know when the active region starts.
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====Display power management====
The DVI specification includes signaling for reducing power consumption.
===Analog===
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==DVI and HDMI compatibility==
[[HDMI]] is a newer digital audio/video interface developed and promoted by the consumer [[electronics industry]]. DVI and HDMI have the same electrical specifications for their TMDS and VESA/DDC twisted pairs.
* HDMI lacks VGA compatibility and does not include analog signals.
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* HDMI sources differentiate between legacy DVI displays and HDMI-capable displays by reading the display's [[EDID]] block.
To promote interoperability between DVI-D and HDMI devices, HDMI source components and displays support DVI-D
Some DVI-D sources use non-standard extensions to output HDMI signals including audio (e.g. [[Radeon R600|ATI 3000-series]] and [[GeForce 200
In the reverse scenario, a DVI display that lacks optional support for [[High-bandwidth Digital Content Protection|HDCP]] might be unable to display protected content even though it is otherwise compatible with the HDMI source. Features specific to HDMI such as remote control, audio transport, xvYCC and deep color are not usable in devices that support only DVI signals. HDCP compatibility between source and destination devices is subject to manufacturer specifications for each device.
==Proposed successors==
* [[IEEE 1394]] was proposed by [[High-Definition Audio-Video Network Alliance]] ([https://web.archive.org/web/20080928130647/http://www.hanaalliance.org/hana_solutions/use_cases HANA Alliance]) for all cabling needs, including video, over
* [[HDMI|High-Definition Multimedia Interface]] (HDMI), a [[forward compatibility|forward-compatible]] standard that also includes [[digital audio]] [[transmission (telecommunications)|transmission]]
* [[Unified Display Interface]] (UDI) was proposed by [[Intel]] to replace both DVI and HDMI, but was deprecated in favor of [[DisplayPort]].
* [[DisplayPort]] (a license-free standard proposed by [[VESA]] to succeed DVI that has optional [[Digital rights management|DRM]] mechanisms) / [[Mini DisplayPort]]
* [[Thunderbolt (interface)|Thunderbolt]]: an interface that
In December 2010, [[Intel]], [[Advanced Micro Devices|AMD]], and several computer and display manufacturers announced they would stop supporting DVI-I, [[
==See also==
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[[Category:Computer-related introductions in 1999]]
[[Category:Digital display connectors]]
[[Category:High-definition television]]
[[Category:American inventions]]
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[[Category:Television transmission standards]]
[[Category:Video signal]]
[[Category:Audiovisual connectors]]
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