HDCP (High-bandwidth Digi-

tal Content Protection) is considered

to be either the best or worst feature

of digital display technology, depend-

ing on who you are. Created by

chip giant Intel, HDCP is an encryp-

tion technology designed to protect

digitally transmitted picture content

from illegal copying and distribution

(piracy). As such, HDCP is relevant

to both DVI and HDMI signal con-

nectivity; with the important footnote

that it may or may not be used with

DVI signals, but is a mandatory re-

quirement for all HDMI signals.

Backed by content produc-

ers (studios) who strongly desire to

protect their investments, HDCP’s

underlying charter is to protect and

maintain control of copyrighted

materials. Let’s look at the piracy

issue more closely. Consider today’s

analog video system. In use for over

50 years, our NTSC video system

was developed in an age where

vacuum tubes were the norm and

solid state devices were unknown.

In these early days, piracy was not

a concern as video tape recorders

were not yet invented. Today, by

their own reports, Hollywood studios

lose billions of dollars per year on

illegal copying and distribution of

movies and other forms of program

material. As we make the transition

from low resolution NTSC video to

high definition television (HDTV), the

concern over piracy is heightened as

the picture quality now more closely

approximates the cinematic quality of

first-run motion picture films. With

its vastly superior picture quality,

HDTV represents a clear and present

danger to the studios. At the same

time, it also represents a major op-

portunity to stem the ?ow of illegally

pirated content. With HDTV signals

encrypted in the digital domain,

HDCP ensures that they are far bet-

ter protected than with the conven-

tional analog signals in use today.

The hope is that, as HDTV rises in

popularity, HDCP will also become in-

creasingly more effective in thwarting

piracy.

Lesson #1: HDCP is backed

by the studios as it helps protect

their product (movies) from theft.

But how exactly does HDCP

work ? HDCP encryption was

developed to protect and maintain

the integrity of content traveling

between two or more digital sources.

Therefore, to make HDCP work,

all equipment in the system must

be fully HDCP compliant, that is, it

must conform to all aspects of the

HDCP standard. An essential aspect

of this compliance is maintaining

the integrity of the HDCP encrypted

content, which can only be decrypted

using special cipher keys. With these

keys in use, display devices (TVs, ?at

screens, projectors, etc.) are able to

display the encrypted video content.

Without these keys, the HDCP signal

cannot be decrypted and hence

cannot be displayed. However, it is

important to note that HDCP en-

cryption does not protect against

illegally copying the information after

the receiving device has received

and decrypted it. Not surprisingly,

the HDCP

specification

places great

emphasis

on degree

that manu-

factures must go to ensure HDCP

cannot be defeated by “hot wiring”

their products.

If a company wishes to

implement HDCP in their products

(most major manufacturers have),

they must obtain a license from

the Digital Content Protection, LLC.

These licenses are expensive, as they

cover the cost of the entire encryp-

tion process and are designed to

prevent “?y-by-night” suppliers from

using HDCP unless they are licensed.

In order to encrypt the

information, HDCP compatible units

contain a set of forty 56-bit keys that

make up the unit’s device private

keys. Each set of these keys is asso-

ciated with the device’s key selec-

tion vector (KSV), which is entirely

unique to that device. Therefore,

each HDCP-compatible transmitter

and receiver has a KSV all to itself.

This KSV allows for transmitters

and receivers to communicate their

encryption to one another in order

to ensure the validity of their content

protection. Only after a two-part en-

cryption process takes place will the

transmitter begin to send information

to the receiver via its digital output

(i.e. DVI or HDMI display port). If

the set of device keys is found to be

invalid or corrupt, the digital picture

information will not be sent from

the transmitter. This process takes

a fraction of a second to complete.

Of course, all the standard analog

ports will still operate with or without

HDCP; however, in the future, these

analog ports will only carry low reso-

lution signals not exceeding 480p.

If you want to enjoy the superior

picture quality of full HDTV resolu-

tion, you must use the digital (DVI

or HDMI) signal ports where HDCP

is a key factor.

Lesson #2: HDCP

compliant devices are a must for any

forward-looking system.

This all sounds simple

DVI-I Female Connector

HDCP - For Better or for Worse?

Technology Connection: Issue 3                                               -1-                                               October 1, 2004

© Copyright 2004 DVIGear

enough, right? Well, not really. Keep

in mind that all devices in the signal

chain must be HDCP compliant.

Even if the devices on either end

of the application are compliant, all

devices in the middle must be as well

(repeaters, converters, switchers,

etc.). Fortunately most cables and

adapters simply pass through the

HDCP information and hence are not

a major concern. For example, if we

are using a DVD player with an HDCP

encrypted DVI output and sending

the signal to a projector, the projec-

tor must be equipped with HDCP. If

we want to show this same content

on two projectors simultaneously,

the DVI distribution amplifier that

we are using must also be equipped

with HDCP. As the application

becomes more complex it becomes

less likely that all the devices will be

HDCP compliant. Remember – if one

device is not HDCP compliant – then

no signal is passed and your screen

goes black.

So, if your system is work-

ing non-HDCP now, why should

you care? Well, many of us are still

viewing prime time TV, DirecTV HD

movies and HDTV via cable networks

using analog connectivity (Y, Pr, Pb)

and it looks just fine. But remember

that the FCC has mandated that by

2007, everything will be digital. So

for HDTV, you will be obliged to use

digital connections (DVI or HDMI)

sooner or later. After viewing a

side-by-side comparison of digital

versus analog connectivity, you may

not want to wait. This is even more

relevant when you keep in mind that

HDCP not only concerns playback of

pre-recorded HDTV movies, but also

live HDTV broadcasts such as TV

shows and sporting events.

Regrettably, there is a down side

to HDCP – it’s called obsolescence.

First, since HDCP is a digital stan-

dard, all our legacy analog video

equipment cannot participate in what

it has to offer. Second, not all manu-

factur-

ers have

adopted

the HDCP

standards

as quickly

as one

might

think.

This has

resulted in many complaints from

end users that have purchased non-

HDCP compliant systems. A typical

example of this problem happens

when an end user purchases a DVD

player with a DVI+HDCP output and

doesn’t understand why his projec-

tor’s DVI input is “dead”.

So what happens if your

display devices aren’t HDCP compli-

ant and you have sources providing

HDCP content? Will your plasma

screen or projector just blow up?

Not exactly, but you may very well

wish it did. In such cases, you’ll be

obliged to fall back on old analog

connectivity which, in the future, will

be limited to 480p resolution – not

exactly true HD. Your digital inputs

will either run with a black screen or

perhaps display a convenient mes-

sage informing you of your HDCP

incompatibility.

Ok, now you realize you’re

stuck with a non-HDCP display with

an HDCP compliant source. What

are your options? The best option is

to return your display and exchange

it for one that is HDCP compli-

ant. Otherwise, unfortunately, your

choices will be limited. Of course,

you could go HD component video

(analog HD), which will still produce

a far superior image to NTSC, but

it’s not HD digital which means your

possibilities for source material may

become increasingly limited as we

approach the all-digital cut-over year

in 2007.

As we converge on the

future, eventually everything will

probably use HDCP. For example,

if you plan on using your new DVI

equipped projector for display of PC

or Mac-based computer signals, you

may still want to go the route of buy-

ing an HDCP compliant model. Com-

puter graphics card manufacturers

will likely be pushed to enable HDCP

of their products as well to protect

digital content. In fact, the Radeon

9700 Profrom ATI already incorpo-

rates HDCP. Currently, you could

use a PC’s DVD player to output a

DVI signal to your non-HDCP display

without problems, but everyone in

the PC industry thinks that will be

short-lived as well. Today HDTV

PC cards exist that allow for off-air

HDTV broadcasts to be routed into a

tuner in your PC that could then send

signal to a non-HDCP DVI Display.

Two popular cards are the MyHD

MDP-120 (available with DVI output

“Daughter Card”) and the Telemann

HiPix DTV-200. Although watching

TV via a PC receiver isn’t the simplest

form of TV

connectiv-

ity to ex-

plain to the

babysitter,

it does

work, for

now…

HDCP attempts to solve a serious

problem that’s plagued the studios

and other content producers for

years and is something that is good

for everyone. In fact, piracy is cited

as the main reason why audio CD’s

never got to that price point was

promised when they debuted in the

early 1980’s. While there is still

much confusion in the marketplace

today due to a lack of understand-

ing, it is clear that HDCP is the wave

of the future and that smart buyers

will look for HDCP compliance as

future-proof protection. Over time,

consumer awareness will improve as

HDCP enabled devices become more

readily available; thus helping fuel

the widespread adoption of digital

HDTV.

If you are interested in learn-

ing more about digital connectivity

or have a special application request,

please contact DVIGear for more

information.

HiPix DTV-200

MyHD

Momitsu V880 Deluxe

DVD Player

Bravo D1 DVD Player

Technology Connection: Issue 3                                               -2-                                               October 1, 2004

© Copyright 2004 DVIGear