Today's high-definition home theaters run on digital audio and video, and HDMI™ is the connection of choice. That's because HDMI (High-Definition Multimedia Interface) delivers crystal-clear digital video and audio via a single cable, dramatically simplifying cabling and helping A/V fans enjoy the best possible home theater experience.

In this article, we'll explain what HDMI is and how it differs from conventional analog connections, and include some quick tips on choosing HDMI cables. You'll also learn what the exact differences are among the evolving versions of HDMI. And finally, we'll look at some real-world HDMI hookup issues along with solutions and workarounds.

HDMI: The "king" of high-quality connections

HDMI's pure-digital interface is the best way to connect high-resolution components — like upconverting DVD players, HD DVD and Blu-ray Disc™ players, the PlayStation® 3 and Xbox 360™ game consoles, and some HD-capable satellite and cable TV set-top boxes — to HDMI-equipped high-definition TVs. And increasingly, devices that are inserted between the source components and the TV — like home theater receivers and video switchers — also include HDMI connections.

Increasingly, home theater fans find HDMI to be the best way to connect components to HDTVs.

Of course, HDMI isn't the first digital video connection for home theater — that distinction belongs to DVI. But DVI, a video-only interface, was originally developed for computer use, while HDMI was designed from the ground up for use with home audio/video gear. Thanks to its superior capacity, versatility, and ease of use, HDMI has largely replaced DVI in home theater equipment.

Single-cable convenience, plus so much more

The ability to send high-definition video and multichannel audio over a single cable is unique to HDMI, but this interface offers other big advantages. A standard HDMI connector has 19 pins, which carry not only audio and video data, but also 2-way control and identification information, and even low-voltage power. HDMI provides maximum signal integrity and a secure, "smart" link between devices — it's one of the best ways to "future-proof" your system. Here are two more reasons to look for HDMI when upgrading your gear:

• Superb picture and sound quality: HDMI connections keep audio and video signals in the digital language of 1s and 0s, eliminating the compromised picture and sound quality caused by digital-to-analog conversions and reconversions. HDMI supports video resolutions up to 1080p, which is key for the new 1080p-capable HDTVs and high-definition disc players. Although there are a few TVs that accept 1080p signals via DVI or component video, it's nearly impossible to find a high-def source that can supply 1080p over anything besides HDMI. And HDMI's sound capability now supports up to 8 channels of super-high-quality 24-bit 192kHz audio.
• Industrial-strength copy protection: This probably seems like more of a benefit for content owners like movie studios than for consumers, but it directly affects the quantity and quality of what we can watch — now, and in the coming years. HDMI's wide adoption is due in large part to Hollywood's demands for ever-stronger copy protection measures to prevent piracy. HDCP (High-bandwidth Digital Content Protection) is present on virtually all HDMI-equipped devices even though it's not officially part of the HDMI spec. Without HDCP, both the quantity and quality of high-def content available to consumers would almost certainly be more limited than it is.
  However, HDCP also has a downside. One of its main jobs is to "authenticate" the connection between two components via a "digital handshake," and problems with this handshake process can result in the loss or degradation of picture and sound.

Quick tips for choosing HDMI cables

Some components include an HDMI cable in the box, but most don't, so you'll need one to connect your gear for the best picture and sound. You won't see dramatic differences in picture quality among HDMI cables. Unlike analog video transmission, which can display varying degrees of picture quality, digital video transmission either delivers a clean, clear picture or no picture at all. But you'll still want to choose a high-quality HDMI cable, especially for longer lengths or in-wall installations. Different cables use different materials and construction techniques, and some are rated by the manufacturer to maintain maximum signal quality over longer cable lengths. Some users have encountered interoperability issues when making HDMI connections, but these are almost never the fault of the cable itself.

Before an HDMI cable can carry the HDMI logo, it must be tested at an HDMI Authorized Testing Center. The tolerances for HDMI cables are incredibly tight: the length of each strand of wire must be within 1/20,000th of an inch to ensure it will work properly.

On the next page, we'll cover some slightly more technical aspects of the HDMI interface and describe the differences among the various versions of HDMI.