Tuner

You've just bought a new HDTV, complete with HDMI connector and are delighted that you had the foresight to buy a DVD player with HDMI interface a while ago, even though you couldn't use HDMI at the time.

So you can ignore those component outputs and inputs and plug an HDMI cable between your two favourite bits of home theater kit. After all, HDMI, being all digital, is bound to be better than component, isn't it?

Well, no, actually. Not necessarily. It's true that convering a DVD signal to analog, sending it over component video and then switching it back to digital in the TV will result in a slight degradation of picture quality. And it's true that HDMI removes this issue. However, the degradation in the signal over component is virtually imperceptable and HDMI does introduce a few problems of its own.

Firstly, although DVD players "up-convert" video from 420p resolution to the native resolution of the HDTV (720p or 1080i), the signal still has to be "re-clocked" in the television before it is displayed. Some experts suggest that this re-clocking introduces more artefacts than the process of digital-to-analog-to-digital conversion. And the quality of the processor in the DVD player doing the "up- converting" is important here, if it's not up to scratch that could have a negative impact on picture quality.

Secondly, any equipment with HDMI (or DVI for that matter) connectors must support an anti-piracy measure known as HDCP (High Bandwidth Digital Content Protection). This takes the form of a code which is embedded into the digital video signal when its sent from a content player, such as a DVD player, and must be de- coded by the HDTV or HD projector. This puts additional pressure on the TV's video processor with no benefit to picture quality and so could, potentially, result in a slight loss in picture quality.

Using component video connections means that no anti-piracy protection is necessary.

None of this means that you should avoid HDMI. However, it does mean that you shouldn't take it for granted that HDMI will always be better than component. The only way to find out which is best for your equipment is to try both and see which one you prefer.

Kenny Hemphill is the editor and publisher of The HDTV Tuner - a guide to the kit, the technology and the programming on HDTV.