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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