What's HDMI?

A new home theater standard worth heeding

By Frank Moldstad

Sharp's all-HDMI home theater at CES.

The next time you go shopping for home theater equipment, you?ll likely run across a new acronym: HDMI. Short for High-Definition Multimedia Interface, HDMI is a universal digital interface connector designed to carry all the audio-video information for your system in a single cable, simplifying hookups and dramatically reducing cable clutter behind equipment racks.

First introduced at the 2003 CES by a coalition of companies that included Hitachi, Matsushita Electric (Panasonic), Philips Electronics, Silicon Image, Sony, Thomson and Toshiba, the format has since gained broad support, and was featured in many new DTVs, set-top boxes and DVD players at the 2005 CES. There was even an all-HDMI home theater system displayed by Sharp.

HDMI has a good lineage, being developed by Silicon Image, the company responsible for the DVI (Digital Visual Interface) format for connecting PCs to flat panel displays. It carries uncompressed standard, enhanced, or high-definition videoand handles up to eight channels of 24-bit/192kHz digital audio. It is backward-compatible with DVI, but when DVI signals are played through HDMI connectors, the multichannel audio does not pass.

Major cable and connector manufacturers such as Monster Cable and Belkin already have introduced full HDMI cable lines.

Besides the reduction in clutter, another advantage of HDMI is that it avoids unecessary digital-to-analog conversion, since DVD players and DTV sets can be directly interfaced via digital inputs and outputs.

Currently, there are an estimated 300 HDMI-capable products on the market, from about 140 manufacturers. If you?re upgrading your system one component at a time, HDMI is a smart feature to look for, even if you have no other HDMI products in your system. In the the interim, components can still be hooked up the old-fashioned way, with a jumble of cables. But ultimately, HDMI looks to be a standard worth heeding for future-proofing as you go.