Let's face it. The transition to HDTV has been a painful and confusing one. It's bad enough that there are now 10 different types of TV technologies available in the market, but what's worse is that display makers, content providers, set-top box manufacturers, and the entire PC industry has been pushing several completely different ways of connecting high definition components since the launch of the first HDTV products in 1998. What's the end result? There are now millions of high definition products in the market, and they all have different plugs on the back. Component video, FireWire, DVI, and HDMI have all graced the back of a TV set at some point over the last eight years, and now consumers are thoroughly confused.

Fortunately, understanding the differences among these types of connections doesn't mean you need a degree in rocket science. With a little bit of knowledge you can get a grasp of the current state of video connections, and learn which digital connection is the one you want to look for when shopping for a new HDTV.

It's a Different Kind of Format War

Few really understand why there's such tension and competition over something as silly as a connector, but it's important to understand why there's such a fight between manufacturers and their partners as to whose format becomes the standard.

There's a lot that goes into creating a standard. Issues like backwards and cross compatibility, cost, features, copy protection, transmission, durability, and a whole lot more. Creating something affordable, feature-packed, and highly protected takes years of research, development, and testing. In other words, creating a standard costs a fortune.

Money, above all else, is the motivating factor behind creating a standard. It's expensive to dump millions of dollars into creating a great connection when no one uses it. On the flip side, it's highly lucrative if it becomes the de-facto standard. Every manufacturer that uses the connector, in most cases, must pay a yearly license fee for use of the product, as well as pay a per-unit royalty for every unit produced that uses it. The royalty fees are not huge ($.15 per unit for HDMI, $.05 per unit if they include the logo on the product), but they add up to serious amounts of money when your licensees are producing items in massive quantities. Think of how many products and cables will be sold that are subject to this royalty and do the math... you'll be surprised at the total.

From Analog to Digital

So the first question is how did we get to where we are today? When the first HDTVs launched, there was no such thing as a digital video connection standard. Most TVs at the time shipped with HD compatible component video inputs or 5-wire RGB connections. These connections transmit signals in the analog domain, and are typically fine for CRT based displays like high-resolution tubes and CRT projection displays.

Falling prices and strong sales of LCD, Plasma, DLP, and other digital display technologies over the last few years have dramatically shifted the market. These sets don't work as well with analog connections like RGB and component video. Integrated analog-to-digital translation usually does a good job of getting images on the screen, but the image quality suffers as a result.

The other reason behind the push to digital connections is the ability to protect high-resolution source material, preventing the creation of digital-to-digital copies. Copy protection has also been a major contributor to the rise and fall of most advanced connection methods. Without a robust protection scheme in place, content providers and major motion picture studios shy away from taking advantage of the higher quality performance.

Three Digital Connections, One Confused Consumer

FireWire Comes and Goes

The first real attempt to providing a digital interface came in the form of an IEEE-1394 (also known as FireWire or i.Link) cable based on HAVi (Home Audio/Video interoperability) communication protocols. This connection was designed to network consumer electronic devices together and provide the consumer with a simple "plug and enjoy" experience. One cable is all that's required to bring audio, video, control and more from one device to another. Since it works like any regular network, one cable would allow the device to communicate with all devices in the network. Pushed primarily by Mitsubishi and RCA, FireWire never gathered industry support from content providers, causing this connection standard to never realize its full potential.

 

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HDTV Goes "PC" With DVI

With LCD flat panels outselling CRT monitors for computers, the PC industry was already battling the aged VGA interface that had become the de-facto standard for more than 15 years. Graphics card and LCD flat panel makers turned to DVI (Digital Video Interface) to better connect personal computers to the growing number of digital LCD displays.

DVI is a versatile connection standard, providing three distinct implementations (DVI-D, DVI-A, DVD-I) for supporting digital-to-digital and digital-to-analog connections in a single cable. This was extremely important in the PC industry, as a single output on a graphics card could support both analog and digital displays.

Taking a queue from the PC industry, consumer electronics manufacturers began adding support for DVI connections on TVs, DVD players, and digital set-top boxes. Unfortunately, DVI is less than ideal for home theater. The sheer size of the connector, though okay for personal computers, takes up too much valuable real estate on electronic devices. Plus, the lack of audio support doesn't help in simplifying the connection process. As an added bonus for content providers, DVI can support HDCP copy protection, though many early TV models don't support it.

Using DVI in the consumer electronics space was a knee-jerk reaction to provide a digital output. Though some consumers enjoy the simplified connection of PCs to digital capable televisions, using the DVI connector for home theater was doomed from the start. Don't expect it to last long in the PC industry either, as the new UDI (Universal Display Interface) standard is looking to supplant VGA and DVI in the PC realm.

HDMI Looks to Stay the Course

HDMI (High Definition Multimedia Interface) and DVI are essentially identical in most respects, which is why appropriate adapters can be purchased to connect one to the other. However, HDMI contains several notable improvements (and stricter technical standards) over DVI, including new features and much smaller form factor to make it friendlier to the home theater market.

One of the biggest improvements to HDMI is that it can carry audio as well, negating the need to connect both audio and video cables to and from every device. Audio support goes well beyond the simple stereo hookup by carrying up to 8 channels of high-resolution audio (32kHz to 192kHz) in formats like Dolby Digital, DTS, DVD-Audio, and SACD. Another improvement is the inclusion of a single wire serial bus that can carry things like remote control commands or other data between the source and the display.

HDMI improves on the max distance you can retain a usable signal. The DVI spec maxed at 5 meters (16 feet), which is typically fine from PC to monitor, but just not enough for long runs from an equipment rack to front-projectors or wall mounted plasma displays. HDMI supports standard copper cables at lengths up to 15 meters (50 feet). Best of all, HDMI cables are cheaper to manufacture than DVI, so the price of a long cable shouldn't cost more than device you're connecting it to.

Most importantly, HDMI is backed by the most powerful electronics manufacturers in the business, and when combined with HDCP copy protection, has widespread support from motion picture producers and system operators. If you head out and look at the latest HD-DVD players and digital set-top boxes, HDMI will be common amongst them all.

Conclusion

When out shopping for your new HDTV, remember that the type of connections it has will impact your ability to connect and view high-resolution sources in the future. Considering its flexibility, robust copy protection, compatibility with the upcoming UDI standard for the PC industry, and the speed of adoption, HDMI with HDCP is the standard you want to look for when purchasing high resolution consumer electronic devices. That combination will ensure that whatever HD source you connect to your display, you'll get the maximum image quality possible and the greatest compatibility with future devices. Think of it as a requirement, not a feature.

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