HD Advice

HDTV is short for High-definition television. HDTV incorporates digital broadcasting that results in a resolution that exceeds standard formats like NTSC (National Television System Committee [named for the group that came up with their resolution standards]), SECAM (Séquentiel couleur à mémoire, translated from French is “Sequential Color with Memory”), and PAL (Phase Alternating Line).

HD televisions are measured by the amount of lines that fit vertically into a television: that means if the TV specifies “720,” 720 vertical lines fit. Likewise, “1080” means that 1,080 vertical lines are present. Another indicator of resolution is the letter that most of the time follows the number. You may have seen HDTV’s advertised as “1080i” or “720p.” The letters indicate the type of scanning the television performs. The “i” means interlaced and the “p” means progressive. Progressive scan is the process of when a frame is taken, transmitted and displayed on the TV in a path from top to bottom, left to right, individual line by individual line. Interlaced is similar to progressive in that the lines are displayed the same way, except every other odd line is displayed first, and then the display goes back and shows the even lines, from top to bottom.

The numbers 720 and 1080 denote how many lines there are vertically, but what about horizontally? In order to answer that you have to think in terms of pixels; which are the smallest portion of a picture on a television. A pixel can be thought of as the point at where a horizontal and a vertical line meet, and the amount of pixels are read from horizontal to vertical. For instance 720 has 1,280 lines running horizontally, so the number is read as “1280 x 720,” therefore there are 921,600 pixels possible in every frame. 1080 has 1920 lines, giving a rise in the pixels amount to 2,073,600. Each pixel is a different color, and that will cause the picture to be much more crisp, more clear and much more brighter than a regular television.

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