High Definitions Defined

These terms, 480i, 480p, 720i, 720p, 1080i and 1080p are all definitions of the level of definition, or resolution. It can be confusing if you don't know what they mean, but they are simple once you understand them. First let's tackle the little letter at the end of the number.

Very simply put, the i stands for an interlaced picture and p stand for progressive scan picture. INTERLACED images are how current tv standards are broadcast. The image is 640 X 480 and because of U.S. 60hz electrical standard, the tv was designed to present every other line on the picture tube alternatively. In other words on one cycle of electrical current all the even numbered lines are projected to your tv screen, and on the next cycle the odd numbered lines are projected making the entire image projected in 1/30th of a second yielding a 30FPS moving picture. PROGRESSIVE scan means each line of the image is projected in turn without skipping any lines.

The numbers represent the number of horizontal lines the image resolution is made of. The primary video image resolutions are 3:2 640 X 480, 4:3 aspect ratio 720 X 480, HD standards 16:9 ratio of 1280 X 720 and 1920 X 1080. The second number of each of these resolution numbers give you the HDTV capability, 480, 720, and 1080, in conjunction with the i or p to designate the resolution and type of image the set is compatible with.

Some say for sporting events the progressive scan is better for producing a less ghosting image, however for the TV watching consumer it is not really an issue because HDTV's should support both formats. The real issue is for the broadcasters and whether or not they choose a 720 progressive scan, (720p), or the 1080 interlaced, (1080i). While the 1080i is a higher resolution, being interlaced can at times cause problems. It really becomes noticeable if you convert a DVD Mpeg2 format, (interlaced) to an mpeg 4 avi format, and choose not to de interlace. When you have images that move or the camera shifts position you can see the alternating lines blurring the vertical edges of objects within the image. The 720p obviously does not have as high a resolution as the 1080i, but being a progressive scan, in my honest opinion, will create a more distinctive and sharp image, especially during high action sequences.

Native resolution is the maximum resolution a screen is made to display. Motion pictuers and images of a different resolution can, and in TV's are typically stretched or shrunk to fit the viewing screen. most LCD TV's coming out now are in widescreen format, and this can distort images from a standard tv broadcast because it must stretch the picture lenthwise to fill the screen. Because of thistransitional legacy of the old vs the new formats, most widescreen TV's have the ability of selecting the format for the video you are watching from 16:9, 16:10, 4:3, etc. I did find one set that did not have this feature and quit promoting it on my site because I feel as though there are too many videos still in circulation that are in original TV format, and this option should be available on any set you purchase.