Wednesday 25 January 2006

HDTV

Whats new?
Superior resolution HDTV offers a number of compelling advantages over its analog forbears. The primary reason is enhanced resolution. A TV picture is made up of lots of tiny horizontal rows (called scan lines) of individual pixels, or picture elements. The more rows—and the more picture elements—a screen can reproduce, the clearer and sharper the picture. Your old analog TV’s picture is made up of 480 visible horizontal lines, each comprising a maximum of 720 pixels. By contrast, HDTVs can reproduce up to 1080 horizontal lines of 1920 pixels—resulting in a jaw-dropping picture that’s six times as dense. HDTV also has the advantage of enabling progressive-scan display (useful with the latest DVD players and gaming systems, as well as TV broadcasts).

Oh and...
You’ve probably also noticed that many HDTV screens are wider, relative to their height, than the TVs you’re accustomed to. To be specific, most newer HDTV models feature what’s known as a 16:9 (widescreen) aspect ratio (the ratio refers to the relationship between horizontal and vertical dimensions), as compared to the 4:3 aspect ratio of older TVs. HDTV programming, by definition, is delivered in this wider aspect, which is better suited to the reproduction of most movies, not to mention providing a broader, more revealing perspective on sporting events and other programs. Regardless of their screen dimensions, all HDTVs and HD-ready TVs can reproduce high-definition programming in its intended 16:9 aspect. 4:3 sets typically handle the conversion by compressing the horizontal scan lines to fit within the vertical picture area, leaving black or gray bars above and below the image (letterboxing).

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