e about the limit, assuming equivalent image quality. Other techniques exist, but they are largely proprietary. These include PLV, Indeo, RTV, Compact Video, AVC, DV, DVCAM, and a few others. Television Standards It's interesting to note that in the drive toward digitization, the ulti- mate goal is to create a video storage and transport technology that will yield as good a representation of the original image as analog trans- mission does. Two primary governing organizations dictate television standards: One is the National Television System Committee, or NTSC (sometimes said to stand for "Never Twice the Same Color" based on the sloppy color management that characterizes the standard); the other, used primarily in Europe, is the Phased Alternate Line (PAL) system. NTSC is built around a 525-line-per-frame, 30-frame-per-second standard, while PAL uses 625 lines per frame and 25 frames per second. While technically dif- ferent, both address the same concerns and rely on the same character- istics to guarantee image quality. Video Quality Factors Four factors influence the richness of the video signal. They are frame rate, color resolution, image quality, and spatial resolution. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Premises Technologies Premises Technologies Frame rate is a measure of the refresh rate of the actual image painted on the screen. The NTSC video standard is 30 frames per second, mean- ing that the image is updated 30 times every second. Each frame consists of odd and even fields. The odd field contains the odd-numbered screen lines, while the even field contains the even-numbered screen lines that make up the picture. Television sets paint the screen by first painting the odd field, then the even. They repeat this process at the rate of 60 fields-or 30 frames-per second. The number 60 is chosen to coincide with the fre