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HDMI, DVI, and HDCP

High Speed and Copy Protected Digital

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HDMI cable.
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Question: If I purchase a new HDTV is it better to purchase one with HDMI/HDCP or DVI/HDCP? If I don't, how can it become HDCP compliant? Some TV dealers have told me that a HDTV without HDCP capabilities is going to be useless if I use HDMI or DVI cables to connect my TV receiver to it. Are these rumors true?

Answer:

The salespeople are correct in this scenario. Buy a HDTV that is HDCP compliant or else be prepared to shake hands with the devil whenever you use HDMI or DVI cables.

The reason I refer to HDCP as the devil is because HDCP is quite possibly one of the worst TV technologies because it stands at the alter of controlling the way we watch digital programming. While the intent of HDCP is noble -- to protect copyrighted material -- the disruption it causes law-abiding TV watchers is far too significant to ignore.

What is HDCP?

HDCP stands for High-Bandwidth Digital Content Protection and was developed by Intel Corporation. It's nothing more than a security feature requiring compatibility between the sender and receiver, like HD cable set-top box and the TV. By compatibility, I mean HDCP technology built into both devices.

Think of HDCP as a security license key like you would input when installing a computer program. Only this security key is invisible to you and me but not your TV.

It works by encrypting a digital signal with a key that requires authentication from the transmitting and receiving product. If authentication fails then the signal fails, which means no picture on the TV screen.

You might wonder, "Who wants a TV signal to fail? Isn't the point of television to enjoy watching it?"

You'd think so but HDCP is about money. The problem is that digital technology makes piracy of content easy. Remember Napster? Ever hear of video pirates that sell movies out of their trench coat? This is the point of HDCP - no illegal reproduction.

This is about copyrights. It's about selling content rather than giving it away. It's no secret that the motion picture industry is embracing HDCP through Blu-ray discs while the TV industry has yet to get involved at this time. Granted, the TV industry has its own share of issues with the implementation of digital TV.

Where is HDCP?

It's critical that you understand that HDCP is a digital technology. As a result, it only works right now with DVI and HDMI cables. Hence the DVI/HDCP and HDMI/HDCP acronyms.

What is DVI?

DVI was created by the Digital Display Working Group, and stands for Digital Visual Interface. It is an older digital interface that has all but been replaced by HDMI in televisions so I won't spend a lot of time on DVI/HDCP. Just know that if you have a HDTV with a DVI input then HDCP could become an issue at some point for you if it hasn't already.

What is HDMI?

HDMI stands for High-Definition Multimedia Interface. It's a digital interface that you'll use with your HDTV to get the best, uncompressed digital picture possible. HDMI has tremendous support from the motion picture industry. It was created by some of the heavyweights in the consumer electronics industry - Hitachi, Matsushita, Philips, Silicon Image, Sony, Thomson, and Toshiba.

There are two significant advantages of HDMI over DVI:

  1. HDMI sends the audio and video signal in one cable. DVI only transfers video so a separate audio cable is necessary.
  2. HDMI is significantly faster than DVI, which means more information transferred to your TV screen.

About.com Guide to Home Theater, Robert Silva, has a wonderful article explaining the differences between every HDMI version.

HDCP Buying Advice

Buy a HDTV that has HDCP capabilities. Most will have this in at least one HDMI input but be sure to verify this before buying the TV.

Notice that I wrote "in at least one port." Not every HDMI port on the TV will be HDCP compliant so be sure to read your TV user manual if you plan on connecting a HDMI cable to your TV.

There is no firmware upgrade that can turn a non-HDCP input into a HDCP compliant input. If you bought a HDTV a few years ago then there is a great chance that you will get a HDCP error when connecting a Blu-ray Disc Player to your HDTV with HDMI. This would force you into either using a non-digital cable, buying a new HDTV or getting rid of the Blu-ray Disc Player.

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