How much better than DVD?
High-definition video (usually abbreviated to hi-def, or HD) represents the crème de la crème of visual entertainment in the home. Where standard-definition sources such as DVD deliver their images at a resolution of 720x576 pixels (or 720x480 pixels in the US and Japan), HD resolutions can reach the giddy heights of 1,920x1,080 pixels -- which means they contain roughly four times the amount of detail. HD video also tends to be better encoded and less compressed than standard-definition pictures, which makes colours brighter and artefacts such as noise less visible.

Feed some HD video to the right television or projector and you'll get an experience far beyond what DVD can offer. Take the climactic Empire State Building sequence of Peter Jackson’s version of King Kong, for example. Watch the standard DVD edition on a big TV and Kong's fur will be a largely indistinct mass of dark grey and black; the buildings and streets of Manhattan, lying in the background, will be slightly fuzzy; and behind them, you'll notice little speckles of noise in the clouds where the video information has been compressed.

Swap it for the HD DVD version and it's as if you've removed a layer of grime and Vaseline from your screen: individual bristles can be made out on Kong's back as he climbs the building, while the cityscape behind leaps to life with clean, razor-sharp edges and the sky becomes crystal clear and noise-free. The improvement, especially on a screen of 42 inches or larger, is nothing short of a revelation.

Different hi-def flavours
HD DVD and Blu-ray can deliver hi-def video in three formats: 720p, 1080i and 1080p. 720p offers the lowest pixel count (its resolution is 1,280x720 pixels) but each frame is scanned on to your screen progressively, or in its entirety, which results in smooth edges during motion.

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