DVI-WhitePaper

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Digital Visual Interface (DVI)

WHITE PAPER

November 2001


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Contents

Executive Summary.......3

Direct Digital Transmission Standards....4

Low Voltage Differential Signaling (LVDS)......4

Transmission Minimized Differential Signaling (TMDS).....4

TMDS Based Digital Transmission Standards......5

Digital Flat Panel (DFP)......5

Plug and Play (P&D)....5

Digital Visual Interface (DVI)..... 5

The Digital Visual Interface (DVI).....6

DVI Connector Classifications..6

DVI-I Connector........7

o DVI-I Connector Pin Assignments...7

DVI-D Connector..7

o DVI-D Connector Pin Assignments ........7

High-bandwidth Digital Content Protection (HDCP)......8

DVI-Audio.....8

Conclusion.......9

Bibliography...10

Questions and Answers (Q&A)...11


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Executive Summary

Most of the computers on the market today generate digital video, which is then converted toanalog by the video graphics card and transmitted to an analog CRT monitor. In the case ofdigital displays such as Plasma, LCD flat panel monitors, DLP and LCD projectors, that analogsignal is then converted back to digital before it can be displayed, a process that can add

unnecessary cost and complexity to some products. Additionally the digital to analog (D/A) andanalog to digital (A/D) conversion of the video signal can introduce sampling errors, which canreduce image quality and require the addition of controls to help correct the errors introduced inthe process.

With the increase in popularity of digital flat panel monitors, the need for a digital graphicsconnection became apparent. The challenge was to develop a simple, cost effective digitalconnection to send high bandwidth digital RGB signals across a reasonable cable length.Solutions based on National Semiconductors Low Voltage Differential Signaling (LVDS)technology and Silicon Images Transition Minimized Differential Signaling (TMDS) technologywere explored. TMDS proved to be better suited to transmit digital signals across long cablelengths than LVDS technology. A number of competing standards for digital interfacing soonemerged. VESA introduced the Plug and Display (P&D) standard, Compaq Corporation led a

consortium of manufacturers to introduce the Digital Flat Panel (DFP) interface standard and theDigital Display Working Group (DDWG) introduced the Digital Visual Interface (DVI) standard. Allthree standards were based around Silicon Images TMDS technology.

The Plug and Display (P&D) standard attempted to implement a multifunction interface withsupport for USB and IEEE1394/Firewire. It failed to attract the interest of video graphics cardmanufacturers and never gained much popularity. The Digital Flat Panel (DFP) standard wasintroduced as a way to simplify the implementation of an all-digital connection. It failed to gainwidespread acceptance because of its limited functionality. The Digital Visual Interface (DVI) wasdesigned to provide the industry with a single, universal digital interface. Its primary focus was toprovide a digital connection between a PC and a display device. It quickly gained widespreadmarket acceptance and is now the industry standard.

DVI offers the right combination of versatility and functionality, which is why it has become theindustry standard. Market research indicates that in just a few years, sales of digital displaydevices will surpass sales of analog display devices. DVI is poised to replace the analog VGAconnector to become the single, universal display interface.


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Direct Digital Transmission Standards

Low Voltage Differential Signaling (LVDS)

National Semiconductors Low Voltage Differential Signaling (LVDS) is a high-speed, low-power

interface used by most Notebook computer manufacturers to create a direct digital connectionbetween the Central Processing Unit (CPU) and LCD display. It provides very high linetransmission rates, requires little power, generates low noise levels and it is very robust. It is alsoable to reject common-mode noise that is twice the magnitude of the actual differential signalmagnitude. LVDS technology was optimized for short cable runs, as a result efforts to transitionLVDS technology to external desktop monitors did not get too far.

Transition Minimized Differential Signaling (TMDS)

Silicon Images Transition Minimized Differential Signaling is an electrical standard used totransmit digital data to a display device. The transition minimization is achieved by implementingan advanced encoding algorithm that converts 8 bits of data into a 10-bit transition minimized, DCbalanced character. The signal is optimized to reduce Electromagnetic Interference (EMI), which

allows for faster signal transfer rates with increased accuracy. The differential circuitry in TMDSallows complimentary limited amplitude signals to be transmitted over twisted pair wires insteadof more expensive coaxial cable. The TMDS link architecture consists of a TMDS transmitter thatencodes and serially transmits a data stream over the TMDS link to a TMDS receiver. Video andsync information are serialized and sent over three sets of twisted pair wires, one set for red,green and blue data channels. An additional pair of wires is used to transmit a clock signal fortiming. At the other end, the TMDS receiver synchronizes itself to character boundaries in each ofthe serial data streams, the transmitted signal is recovered and decoded.A fundamental principle of physics known as the "Copper Barrier" limits the amount of data thatcan be squeezed through a single copper wire. The limit is a bandwidth of about 165MHz, whichequates to 165 million pixels per second. A single TMDS link has a bandwidth of 165 MHz, whichenough to display resolutions of up to 1600 x 1200 (UXGA) at 60Hz.DVI, which is the first standard specifically written for the TMDS digital interface allows for up to

two TMDS links, a total of 6 channels sharing a single clock, to be integrated into a single DVIconnector to support a minimum bandwidth of 330 mega pixels per second. That is enoughbandwidth to enable digital displays to reach resolutions of up to 2048 x 1536 (QXGA).


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TMDS Based Transmission Standards

Plug-and-Display (P&D)The P&D standard attempted to implement a multifunction connector capable of carrying digitaland analog signals, as well as USB and IEEE1394/Firewire. Although the P&D connector failed to

attract the interest of graphics card manufacturers, InFocus Corporation, one of the leaders of theprojection industry, has found a great application for this connector in its products. By using theP&D connector, which InFocus calls the M1-DA, on the display side, InFocus has created anorganized, single-cable connection solution between the host computer and the display. Inrecognition of this, VESA has officially released the M1 standard, making this the first time that aprojector manufacturer has played such a pivotal role in the creation of a connector standard.

P&D/M1 ReceptacleConnector

Digital Flat Panel (DFP)Adopted by VESA and now considered obsolete, the DFP standard was designed to simplify theimplementation of a direct digital connection between the host computer and a digital flat panelmonitor. DFP supports the Display Data Channel (DDC) and Extended Display Identification Data(EDID) specifications for configuration management. It also supports Hot Plug Detection forcompatibility with the P&D VESA standard. It does not support the transmission of analog signalsand it does not support USB or IEEE1394/Firewire. Its maximum resolution is limited to SXGA(1280 x 1024), which made it the least future-ready of the three standards.

DFP ReceptacleConnector

Digital Visual Interface (DVI)The Digital Visual Interface (DVI) was designed to provide the industry with a single, universaldigital interface. Its primary focus was to provide a digital connection between a PC and a displaydevice. The DVI interface has proven to be extremely versatile. Its two connector styles providemanufacturers with the flexibility to support digital devices while remaining backwards compatiblewith analog devices. DVI is also backwards compatible with the Plug and Display (P&D) andDigital Flat Panel (DFP) standards through the use of adapters. Since its release, DVI has gainedextra functionality and can now be used to deliver secure content to a display device as well asdeliver the highest quality digital audio signals. The DVI interface has gained industry wideacceptance and is considered the industry standard digital graphics interface. The projectionindustry has embraced DVI in a big way. Making the DVI connector a standard feature on themajority of new projector models on the market.

DVI-D DVI-IReceptacle Connector Receptacle Connector


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The Digital Visual Interface (DVI)

The DVI standard was introduced by the Digital Display Working Group (DDWG) to create auniversally accepted digital interface and to provide the industry with a path towards a singlecommon display interface. DVI is based on Silicon Images Transition Minimized DifferentialSignaling (TMDS) technology, which provides a high-bandwidth digital connection between the

host computer and a display device. The TMDS technology also makes DVI backwardscompatible with the Plug and Display (P&D) and Digital Flat Panel (DFP) standards through theuse of adapters.DVI is the first digital standard specifically created for Transition Minimized Differential Signaling,It supports a dual-link mode, which allows digital displays to reach resolutions up to 2048 X 1536(QXGA) and beyond.The DVI specification supports hot plug and play of display devices. DVI also supports the VESADisplay Data Channel (DDC) and Extended Display Identification Data (EDID) specifications,which enable the display, graphics adapter, and computer to communicate and automaticallyconfigure the system to support the different features available in the display. EDID is a standarddata format for information such as display vendor, resolution and timing capabilities. A purelydigital connection allows projector manufacturers to design products, which provide the sharpest,clearest image possible, without the need for any fine sync or complex pixel clock adjustments.

DISPLAY RESOLUTION CHART

Resolution Name Pixel Resolution

Video Graphics Array (VGA) 640 x 480

Super VGA (SVGA) 800 x 600

Extended Graphics Array (XGA) 1024 x 768

Super XGA 1280 x 1024

Ultra XGA 1600 x 1200

High Definition TV (HDTV) 1920 x 1080

Quad XGA (QXGA) 2048 x 1536

RESOLUTIONS SUPPORTED BY DVIDisplay Single-Link DVI Dual-Link DVI

60-Hz LCD with 5% blankingInterval

Up to 1920 x 1080 (HDTV) Up to 2048 x 1536(QXGA)

75-Hz CRT with approx. 15%blanking interval

Up to 1280 x 1024 (SXGA) Up to QXGA

85-Hz CRT with approx. 15%blanking interval

Up to SXGA Up to HDTV

DVI connector classifications

The DVI standard was carefully crafted to provide a path to the eventual replacement of theanalog VGA connector. For that purpose the DVI interface is composed of two connector types.The DVI-Integrated (DVI-I) which can carry a single or dual-link digital signal and/or can carry ananalog signal to support legacy analog devices and the DVI-Digital-only (DVI-D) connector whichcan carry a single or dual-link digital signal.


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DVI-Integrated (DVI-I):supports both analog and digital connections to the display. This 29-pin connector can carry single or dual-link all-digital video/data signals on 24 pins and uses 5pins to carry analog video/data signals and ground. It is easily distinguishable by the plus-shaped slot surrounded by four pins used to carry the analog connection.

DVI-IReceptacle Connector

COMBINED ANALOG AND DIGITAL CONNECTOR PIN ASSIGNMENTS

Pin Signal Assignment Pin Signal Assignment Pin Signal Assignment

1 T.M.D.S. Data2- 9 T.M.D.S. Data1- 17 T.M.D.S. Data0-

2 T.M.D.S. Data2+ 10 T.M.D.S. Data1+ 18 T.M.D.S. Data0+

3 T.M.D.S. Data2/4 Shield 11 T.M.D.S. Data1/3 Shield 19 T.M.D.S. Data0/5 Shield


5 T.M.D.S. Data4+ 13 T.M.D.S. Data3+ 21 T.M.D.S. Data5+6 DDC Clock 14 +5V Power 22 T.M.D.S. Clock Shield

7 DDC Data 15 Ground(return for +5V, Hsync,and Vsync)

23 T.M.D.S. Clock+

8 Analog Vertical Sync 16 Hot Plug Detect 24 T.M.D.S. Clock-

C1 Analog Red C2 Analog Green C3 Analog Blue

C4 Analog Horizontal Sync C5 Analog Ground(analog R,G, &B return)

DVI-Digital (DVI-D): supports digital-only connections between the host computer and

display. This interface is designed for a 12 or 24-pin connection to enable single or dual-linkmode activation.

DVI-DReceptacle Connector

DIGITAL-ONLY CONNECTOR PIN ASSIGNMENTS

Pin Signal Assignment Pin Signal Assignment Pin Signal Assignment


2 T.M.D.S. Data2+ 10 T.M.D.S. Data1+ 18 T.M.D.S. Data0+3 T.M.D.S. Data2/4 Shield 11 T.M.D.S. Data1/3 Shield 19 T.M.D.S. Data0/5 Shield


5 T.M.D.S. Data4+ 13 T.M.D.S. Data3+ 21 T.M.D.S. Data5+

6 DDC Clock 14 +5V Power 22 T.M.D.S. Clock Shield

7 DDC Data 15 Ground (for +5V) 23 T.M.D.S. Clock+

8 No Connect 16 Hot Plug Detect 24 T.M.D.S. Clock-


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The DVI connectors have a clever design feature that allows a Digital-only DVI-D plug to connectto both the DVI-D and DVI-I receptacle. In contrast the DVI-I plug can connect only to DVI-Ireceptacles. This design feature ensures that a Digital-only device is not connected to an Analog-only device.

High-bandwidth Digital Content Protection (HDCP)

Future applications for DVI will include secure digital content delivery. Broadcasters and moviestudios have raised concerns about the possibility of copyright violations now that the means todeliver high-bandwidth, high-definition content is here. Anyone could conceivably make perfectcopies of copyrighted material. For that purpose the High-bandwidth Digital Content Protection(HDCP) encryption specification was developed. HDCP is designed to provide a securetransmission, which provides copy protection between a DVI video transmitter and a DVI videoreceiver or display device. The system will require HDCP-enabled hardware on both the hostgraphics system and the display device to provide a protected link. An HDCP encoding scheme isused to encrypt data at the source, before it is sent to the display device. The display device willthen have to present a set of keys, which will unlock and allow the display of the digital content.

DVI-Audio

Silicon Image has developed an audio solution that is fully backwards compatible with the DVIstandard. It is called DVI-Audio and it and it has the bandwidth to support anything from twochannel digital stereo transmitted to HDTV, to 8 channel digital audio or DVD-Audio transmitted toan A/V receiver. This clever solution works by embedding the audio signal into the clock signal.DVI-Audio takes advantage of Transition Minimized Differential Signaling (TMDS) ability tomodulate the position of the falling edge of the clock to send 1 bit of data during each clock cycle,without affecting the functionality of the display device and without the need of software drivers.Through this process, a minimum of 25 Mbps can be sent. That is enough bandwidth to supportexisting digital audio standards with leftover capacity to support future standards. Whentransmitting HDTV resolutions, this capacity is extended to 74.5 Mbps to enable multiple digitalaudio channels, well in excess of todays audio technology.


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CONCLUSION

The DVI interface has gained industry wide acceptance and is considered the industry standarddigital graphics interface. It offers the right combination of versatility and functionality. DVI can beused to deliver single or dual-link digital video to a display device while supporting legacy analogdevices. Leading market research firms are forecasting dramatic rises in sales of digital displaydevices, which will eventually surpass sales of the current analog display devices. Market surveysindicate that over 50% of the displays sold in Japan today, are digital. DVI is also spreading intothe consumer market. There are plans to add the DVI connector to HDTV sets, Set-top boxes,DSS receivers and HD-DVD players. DVI is poised to replace the analog VGA connector tobecome the single, universal display interface.


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Bibliography

Understanding Direct Digital Technology Extron Electronicshttp://www.extron.com/download/files/appbrochure/directdigital.pdf

Chang, Luke and Goodart, Joe Digital Visual Interface Dell Computer Corporationhttp://www.dell.com/us/en/arm/topics/vectors_2000-dvi.htm

Multimedia/Panel Displays, PC Tech Guide.comhttp://www.pctechguide.com/07pan2.htm

High-bandwidth Digital Content Protection (HDCP) Silicon Image. Inc.http://www.siimage.com/documents/SiI-WP-002-A.pdf

PanelLink A/V: The Digital Solution for HDTV Silicon Image, Inc.http://www.siimage.com/documents/SiI-WP-003-A.pdf

Digital Video Solutions-PanelBus Texas Instruments Inc.

http://www.ti.com/sc/docs/products/msp/intrface/panelbus/market.htm

Goldie, John LVDS based FPD-Link spans industries with Gigabits @ milliwatts! NationalSemiconductor Inc. http://www.national.com/nationaledge/may01/lvds.html
http://www.extron.com/download/files/appbrochure/directdigital.pdfhttp://www.extron.com/download/files/appbrochure/directdigital.pdfhttp://www.dell.com/us/en/arm/topics/vectors_2000-dvi.htmhttp://www.dell.com/us/en/arm/topics/vectors_2000-dvi.htmhttp://www.pctechguide.com/07pan2.htmhttp://www.pctechguide.com/07pan2.htmhttp://www.siimage.com/documents/SiI-WP-002-A.pdfhttp://www.siimage.com/documents/SiI-WP-002-A.pdfhttp://www.siimage.com/documents/SiI-WP-003-A.pdfhttp://www.siimage.com/documents/SiI-WP-003-A.pdfhttp://www.ti.com/sc/docs/products/msp/intrface/panelbus/market.htmhttp://www.ti.com/sc/docs/products/msp/intrface/panelbus/market.htmhttp://www.national.com/nationaledge/may01/lvds.htmlhttp://www.national.com/nationaledge/may01/lvds.htmlhttp://www.national.com/nationaledge/may01/lvds.htmlhttp://www.ti.com/sc/docs/products/msp/intrface/panelbus/market.htmhttp://www.siimage.com/documents/SiI-WP-003-A.pdfhttp://www.siimage.com/documents/SiI-WP-002-A.pdfhttp://www.pctechguide.com/07pan2.htmhttp://www.dell.com/us/en/arm/topics/vectors_2000-dvi.htmhttp://www.extron.com/download/files/appbrochure/directdigital.pdf


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Questions and Answers (Q&A)

Q: What is DVI?

A: DVI or Digital Visual Interface was created by a consortium of computer industry leaders

called the Digital Display Working Group (DDWG) as a way to transport video digitally from apersonal computer to a desktop display. The DVI 1.0 standard was first released in April 1999.More recently DVI has gained support from home entertainment equipment manufacturers as away to eliminate many of the sources of image imperfections associated with older analoginterfaces. See: www.ddwg.orgfor more information on DVI.

Q: Whats so great about DVI?

A: In a modern home theater system the video source is often a DVD player. The data onthe DVD is digital, much like it is on an audio CD. Similarly, many home theater projectors use adigital imaging device like DLP, LCD, or LCoS. With a digital source and a digital display it reallymakes no sense to use an analog interface to connect the two.

Analog interfaces are prone to image degradation and artifacts such as: noise, sparkles,ghosting, snow, poor color matching, and softness caused by a loss of sharpness.Additionally, projectors using pixelated imagers must convert the analog video to digital to bedisplayed. This analog to digital conversion introduces artifacts into the image as well.

DVI, being a digital interface, suffers from none of these problems.

In addition to transporting video from the source to the display without degradation, DVI offersother advantages as well. For instance, the Motion Picture Association of America (MPAA) hasendorsed a copy protection standard called HDCP, specifically for DVI. The MPAA has beenreluctant to release high definition movies until there was some way to prevent them from beingcopied. HDCP allows the user access to high definition movies over DVI. The MPAA will notallow high definition content to be available over analog interfaces once HDCP goes live. Thismeans that only projectors with both DVI and HDCP will be able to display high definition content.

Q: Why dont I see any difference when I use DVI instead of the analog interface?

A: Many users will not see any difference when using the DVI interface instead of the analoginterface. This is especially true if the video interconnection cable is short, well designed andmanufactured, and the displayed images are not very demanding. Photographs and normalcomputer desktop displays are not very demanding. The differences become more apparent withtest images designed to push the capabilities of the interface. The differences become readilyapparent with long cable lengths, poor analog cabling, and with higher resolution displays.

Try using test images from Display Mate (www.displaymate.com). Note that with DVI the lines

between the vertical color bars are sharp and the checkerboard patterns show no noise orblurring. Now try the same test with the analog interface. Try again with a long, thin analogcable. The image quality difference should be readily apparent with long, thin analog cables.One could also devise a test to demonstrate that the color matching on the DVI interface is betterthan on the analog interface.

Having said all of that, image quality is a highly subjective thing. What looks fine to one personmay look terrible to another.
http://www.ddwg.org/http://www.ddwg.org/http://www.displaymate.com/http://www.displaymate.com/http://www.displaymate.com/http://www.ddwg.org/


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Q: Why should I buy a projector with a DVI interface?

A: DVI is fast becoming the interface standard of choice for set-top box manufacturers.Additionally, several manufacturers of DVD players are planning to make DVI enabled DVDplayers. By purchasing a projector with a DVI interface you are future proofing your investment.You can further future proof your investment by purchasing a projector with HDCP.

Q: Ive heard about DVI-CE. How is DVI-CE different than DVI 1.0?

A: DVI-CE is a proposed enhancement of DVI 1.0 to make it more applicable to homeentertainment devices, not just computers. Most of the proposals for DVI-CE include a smallerconnector and an audio interface over the DVI link. In all of the current proposals, an inexpensivepassive adapter will allow users of the DVI enabled displays to connect to proposed DVI-CEsources. There are at least two difference proposals for audio over DVI. At the time of thiswriting, Fall 2001, the DVI-CE standard is not yet complete, so a definite answer cannot be givenas to the exact nature of DVI-CE.

Q: What is HDCP and what does it have to do with DVI?

A: HDCP stands for High-Bandwidth Digital Content Protection. HDCP prevents a casualuser from copying high-resolution movies from the DVI port of a computer or other video source.HDCP is specific to DVI interfaces. More information can be found at www.digital-cp.com

Q: If a projector has DVI does that mean it has HDCP?

A: No. Many projectors have a DVI interface, but few have HDCP. Check themanufacturers datasheet carefully. On the other hand, if the projector has HDCP it must alsohave DVI.

Q: What does HDCP do for me as a user?

A: HDCP allows you to view movies in high definition format. Video sources playing highdefinition movies connected to projectors without HDCP are required to reduce the resolution oftheir outputs. The idea is to allow users of older projectors without HDCP to view new movies(albeit in lower resolution), but not allow thieves to make high definition copies. Owners ofprojectors with HDCP will be able to view high definition movies in full high definition resolution.

Q: When will HDCP Go Live?

A: The MPAA has not given a specific date when they will require HDCP on DVI when

showing so-called protected content. However, many industry analysts believe that therequirement for HDCP will be tied to licensing of the new HD-DVD standard. So one mightexpect HDCP to become a requirement to view high definition content when the HD-DVD playersand content begin showing up in retail outlets.

Q: So when will HD-DVD players and content become available?

A: So far, nobody is saying. The main outstanding technical hurdle for the mass productionof HD-DVD players is the long-term reliability and cost of the blue laser diode required to pack HDcontent on a standard size DVD.
http://www.digital-cp.com/http://www.digital-cp.com/http://www.digital-cp.com/


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Q: Ive heard that HDCP was hacked. Does this mean that HDCP is useless?

A: At least one prominent cryptographer has proposed a way that one might hack HDCP.As of the time of this writing, Fall 2001, nobody has posted a hack of HDCP to a public site. Inany case, HDCP was not designed to be uncrackable. It was designed to prevent the casualcopying of specific high definition video content. The Motion Picture Association of America(MPAA) still supports HDCP for use on DVI interfaces.

Q: Ive heard that DVI cables are limited to 5 meters in length. What do I do if I need alonger cable?

A: The DVI standard specifies no specific cable length. The practical cable length isdependent on the quality of the cable, the pixel clock rate of the video being transported, and thequality of the DVI transmitter and receiver being used. For example, 1024 x 768, 24 bits-per-pixel(bpp), 60Hz video has a pixel clock rate of about 65 MHz. For this example, most reasonablequality cables will work fine at 5 meters with InFocus projectors. Better quality cables will work

well at 10 meters. InFocus has taken pains in the design process to optimize the performance ofthe DVI receivers used in InFocus projectors to give the longest cables run possible.

If DVI cable runs longer than 10 meters are desired there are several DVI cable extensionproducts available. Extron (www.extron.com), Altinex (www.altinex.com), Gefen(www.gefen.com), and Opticis, (www.opticis.com)all have DVI extension solutions available.

Q: What is the M1 connector system?

A: The M1 Display Interface System is a standard created by the Video ElectronicsStandards Association specifically for displays. It was approved by the VESA membership inAugust 2001.

Q: Why does InFocus use M1 when everybody else is using DVI?

A: InFocus is committed to making projector as simple as possible to use. To that end,InFocus supports Plug-and-Play for monitors, referred to in the industry as DDC (Display DataChannel) and/or EDID (Extended Display Interface Data). It gets rather complicated, but thereare several problems involved with getting DDC and EDID to work properly on dual-mode (bothanalog and digital) displays using the DVI connector. This is because the DVI connector was notdesigned for use on the display side of the interface, only the host or computer side. The M1connector system fixes the problems with DDC/EDID as well as adding additional features suchas USB, and power for external devices such as fiberoptic DVI link extenders. M1 also makes itmore difficult to confuse inputs and outputs on video processing equipment, since DVI is always

and output and M1 is always an input.

Q: How can InFocus advertise DVI compatibility when using the VESA M1 system?

A: VESA designed the M1 system to work seamlessly with DVI connectors on the host(video source) end of the cable. In engineering terms, M1 is a superset of DVI. Additionally, theDVI standard is agnostic with regard to the connector used on the display end of the video cable.All InFocus projectors using the M1 interface are fully DVI compliant.
http://www.extron.com/http://www.extron.com/http://www.altinex.com/http://www.altinex.com/http://www.gefen.com/http://www.gefen.com/http://www.opticis.com/http://www.opticis.com/http://www.opticis.com/http://www.gefen.com/http://www.altinex.com/http://www.extron.com/


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Q: I heard that M1 is an InFocus proprietary interface?

A: M1 is a standard from the Video Electronics Standards Association, VESA. As such it is anopen standard that can be used by any VESA member company. While InFocus was a drivingforce behind creating the M1 standard, it is not a proprietary interface.

Q: If M1 is so great, why dont all projector manufacturer use it?

A: The M1 standard was just completely ratified by VESA in August 2001. InFocus expectsthere to be other projector manufactures to embrace M1 as soon as development allows.

Q: Why doesnt InFocus put an IEEE 1394 interface on their projectors?

A: IEEE 1394 goes by many different names in the industry. Apple, the inventor of thetechnology, calls it Firewire. Sony calls it iLink. Apple created the basic technology in 1986and introduced it into the market in 1987. The Institute of Electrical and Electronic Engineersmade it an IEEE standard in 1994.While the overall information carrying capacity or bandwidth of IEEE 1394 has increased from

100MHz, to 400 MHz now and 800 MHz on the horizon it still does not have enough bandwidth tocarry uncompressed full-motion video.

In a typical home theater setup there is some sort of central routing box; a cable or satellite set-top box or a video switcher. Many of these devices have a picture-in-picture (PIP) capability.Decompressing the incoming 1394 video streams to this box to perform the PIP function and toadd menus and then re-compressing the video to the display would introduce unacceptableartifacts. This compression and decompression also adds substantial cost.

For these reasons most manufacturers of set-top boxes and video processors are planning to useDVI (with HDCP) to connect to the display. Most InFocus projectors already have a DVIinterface.

Motion Adaptive DeinterlacingPer-pixel motion adaptive techniques provide the highest resolution picture while suppressingmotion artifacts.DCDi (Directional Correlational De-Interlacing)Per-pixel selection of edge direction produces a smooth and natural picture without staircasing orjaggies.Film Mode ProcessingOne field look-ahead allows for superior 3:2 and 2:2 pulldown detection along with bad-edit andmixed-mode detection, which is then coupled with proper inverse pulldown correction for anartifact-free picture.Motion Adaptive Cross Color Suppression3D processing removes objectionable NTSC cross color artifacts created by the Y/C separationprocess.

What is DCDi?

DCDi stands for Directional Correlational De-Interlacing. Conventional video deinterlacingintroduces image artifacts such as flicker, loss of vertical resolution and jagged edges. Moreadvanced motion adaptive deinterlacing can remove most of these shortcomings, but movingdiagonal edges may still exhibit staircasing or jaggies.

Why do I need it?


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The shortcomings of conventional deinterlacing are most apparent when viewing material from alive or taped video source. In particular, television sports, variety, and concert presentations aresignificantly improved by the use of this latest technology.

Broadcast television and other composite video sources are also enhanced by motion adaptivecross-color suppression. Cross-color is the artifact created when fine detail is mistakenly seen ascolor information by conventional video decoders. Think of the rainbows seen in a suits fabrictexture, worn by an anchorperson or talk show host. Those artifacts are now considerablyreduced or eliminated.

What about DVDs?

If the DVD contains material from a video source then the benefits mentioned above will apply. Ifthe DVD contains a motion picture shot on film, then a different method is used to create anoptimum image. Film mode processing reconstructs the original progressive film image from theinterlaced DVD output. Advanced 3:2 and 2:2 pulldown detection gives outstanding results fromNTSC or PAL video sources.

What about progressive DVD players?

Progressive material is displayed directly and very little signal processing is performed. TheLS110 and ???? will display a fine image from these sources. However, you will find thedeinterlacing and film mode processing of our new projectors superior, to many DVD players onthe market today.

What about HDTV?

InFocus does not use DCDi technology to enhance HDTV sources in our present products.

Documents

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