HD is defined primarily by video resolution, which is substantially higher than that of traditional television broadcasts. It provides for between one and two million pixels per fame that is roughly five times that of standard definition television. However, high definition is not defined by only one set of specifications; it is instead a family of video characteristics. Initially, HD referred to a video signal that consisted of 720 horizontal lines from top to bottom and 1280 vertical lines from side to side. Compare this to the 480 horizontal lines you find on a conventional DVD movie. Obviousally, the greater the number of lines of resolution, the greater is the amount of detail that can be captured and displayed. Therefore, the first thing you will notice when viewing HD is sharper image. HD has now come to encompass one more resolution option: 1080 vertical lines and 1920 lines of horizontal resolution. Every manufacturer references only the horizontal resolution when referring to HD products-either 720 or 1080.
HD is also defined by the video frame rate- this includes 23.98, 24,29.97, 30, 59.94and 60 frames per second. The frame rate chosen depends upon the video standard used-Either PAL or NTSC. Next, you will come across another video term-progressive scan or interlaced scans. This is referred to with either a 'p' or an 'i' respectively written after the numeric resolution value. Progressive scan implies that video frame on your screen is created by sequentially 'drawing' one scan line after another. On the other hand, an interlaced picture is created by first drawing all even numbered lines, and then interleaving the odd numbered lines on the screen.
On HD compliant products such as blue ray players, this specification is mentioned along with resolution supported -720p, 1080i and 1080p in order of increasing quality. 1080p is often referred to as 'Full HD'.
Enjoy HD, but at the slightly lower rating 720p. At this resolution video will be slightly scaled down and you won't be able to enjoy the true potential. Older CRT TVs do not support HD at all. They will however support your set top box and you can view the regular DTH. Ensure the set top box TV are connected using an HDMI cable.
