CNET'S QUICK GUIDE: HDMI and HDMI cables

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HDMI versions
One of the most confusing aspects of HDMI is that there are several different versions. While most new products support HDMI 1.3, many older products support older HDMI iterations, such as HDMI 1.2. Much has been made about HDMI 1.3 and its increased bandwidth, but it offers few real-world benefits. Yes, it adds support for "Deep Color"--which is an expanded color gamut--but outside of a few high-def camcorders, there aren't any sources that actually use Deep Color. There are no current or announced Blu-ray discs that use Deep Color. HDMI 1.3 also adds automatic lip-syncing, but we haven't had any problems with lip-syncing on previous HDMI versions.

The major upgrade for HDMI 1.3 is that it enables the ability to send high-resolution soundtracks such as Dolby TrueHD and DTS-HD Master Audio in bit stream format. While all HDMI versions can handle these soundtracks if they've first been converted to PCM format by a compatible player, HDMI 1.3 is needed if they are to be sent in encoded bit stream format. It's certainly counterintuitive--since these soundtracks are actually losslessly compressed in bit stream format and therefore require less bandwidth--but that's the way it works. This feature is also likely to become much less important as new Blu-ray players with onboard decoding for all high-resolution soundtracks become available.

Another important note for HDMI 1.3 is that it doesn't guarantee the support of any of the features we mentioned--Deep Color, automatic lip-syncing and bit stream audio support are all optional features that manufacturers can choose to include. In other words, you're better off ignoring what HDMI version a product supports and just focusing on what features it has.

It's also worth noting that, according to a spokesman for HDMI itself, "98 percent" of all HDMI cables work fine with HDMI 1.3. So there's no reason to buy special cables that support version 1.3.

What about long cable runs?
Like all cable types, signal strength deteriorates over long cable runs with HDMI. While there is no official "maximum cable" length determined by the HDMI Licensing group, they hint at 10 meters (about 33 feet) being the rough guide as when users may begin to experience problems. That's definitely not a hard-and-fast rule--we've had very few issues using a 65-foot HDMI cable from Accell in CNET Labs and Monoprice's 75-foot HDMI cable has positive user reviews. Cable quality isn't the only factor--the individual HDMI inputs and outputs on your HDTV and high-def components can affect signal quality over long distances too--so you'll need to experiment to see what works in your setup. Again, the best advice we can give is to make sure you buy from a retailer with a good return policy.

HDMI switchers

With so many new products featuring an HDMI port, many home theater enthusiasts are likely to run out of HDMI inputs on their HDTVs and AV receivers. Luckily, there's an easy way to add HDMI connectivity without buying a new HDTV: HDMI switchers. All you have to do is connect your HDMI gear to the switcher and connect the output of the switcher to your HDTV or AV receiver, then you can select with HDMI component you want via the switcher. Almost all HDMI switchers operate using a standard IR remote, so you can switch between components easily or integrate the switcher into your universal remote's control scheme. Check out CNET's roundup of HDMI switchers for more buying advice.

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 would never notice. The real trade-off 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.

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