HDCP

HDCP stands for High-bandwidth Digital Content Protection, and it is the copyright protection scheme used by HDMI devices. When two devices are connected via HDMI, HDCP requires them to continually "handshake", or verify that both are authorized devices. Copyright protection is strongly desired by media companies, such as movies studios, to prevent unauthorized copying of movies and television shows.

How HDCP can mess up HDMI, and how to handle it

For all the great things about HDMI, it can cause some headaches. The main culprit is HDCP. Unfortunately, not every "handshake" goes smoothly, and you could be faced with slow switching speeds, a screen filled with static, or a signal that flashes on and off. To make matters worse, it's impossible to know if two products are going to have a compatibility problem--some devices just don't work together well, even if they match with other devices flawlessly. The only way to know is to plug it into your home theater and try it out.

If HDMI compatibility problems are plaguing your home theater, you can try swapping different products in until you get a better match, but that is expensive and time-consuming. Cable boxes are notoriously troublesome HDMI products, and unfortunately you're usually stuck with whatever box your cable company offers. If you can't fix your problem, there's no shame in going back to component-video.

Manufacturers and salespeople often tout the visual benefits of HDMI over component-video, but the reality is that the difference between HDMI and component video is pretty small--again, we're betting the majority of viewers will never notice. The real tradeoff is on the audio side, since you'll need to connect additional digital audio cables (optical or coaxial), or deal with bulky analog audio cables.

Additional HDMI resources

HDMI.org's FAQ
Source: HDMI Licensing, LLC.
Our take: This is the official FAQ of the HDMI Licensing organization, and includes some of the more technical details about HDMI. Some good content, but aware of some spin on topics like HDCP and HDMI's advantages over component video.

The Ins and Outs of HDMI
Source: CrutchfieldAdvisors.com
Our take: Another useful guide to HDMI, if you're still looking for more information.

Wikipedia: HDMI
Source: Anonymous contributors
Our take: Like much of Wikipedia, there is a lot of good info, but it's extremely technical and loaded with jargon. If you want to know what each of the 19 pins on an HDMI connector does, this is your guide.