The simple reason is that the wider view is closer to the human vision. Our vision is optimized within a 30-degree field, and beyond 30-degree there is no visible benefit. The central area of this field provides us the best view, but the peripheral vision is better at detecting motion. Where the 4:3 aspect ratio of analog television allows us only a 10-degree field of vision, HDTV allows us a complete 30-degree.
Note: Do not confuse the aspect ratio with the screen size. The screen size is the diagonal measurement. HDTV comes in multiple sizes, but the aspect ratio is always 16:9.
Resolution
HDTV comes in two different resolutions – 1080i and 720p. The ‘i’ in 1080i means interlaced, and the ‘p’ in 720p means progressive. In both the resolutions, every second consists of 60 frames of video.
Progressive Resolution
Progressive resolution puts 60 full frames on the screen every second. The 720p video resolution is 1280 X 720 pixels, which gives 921,600 total pixels.
Interlaced Resolution
Unlike progressive resolution, interlaced resolution puts half and half, 30 frames of odd lines and 30 frames of even lines, on the screen every second. Some people complain that it causes flickers on screen.
However, the fact is you see the complete image on your TV screen two times more often, which results in smoother motion, and the flickers, if at all they exist are not visible.
The 1080i video resolution is 1920 X 1080, which gives whopping 2,073,000 pixels.
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