used by DVD and digital television. IMAGE 1 Best connection method There is always the question of "what is the best con- nection method for equipment?" For DVD players and digital cable/satellite/terrestrial set-top boxes, the typi- cal order of decreasing video quality is: 1. HDMI (digital YCbCr) 2. HDMI (digital RGB) 3. Analog YPbPr 4. Analog RGB Figure 7.1-1 Video is composed of a series of still images. 5. Analog S-Video Each image is composed of individual lines of data. 6. Analog Composite Some will disagree about the order. However, most The composite sync signal is a combination of both ver- consumer products do digital video processing in the tical and horizontal sync. YCbCr color space. Therefore, using YCbCr as the in- Computer and consumer equipment that uses analog terconnect for equipment reduces the number of color RGB video usually uses technique 1 or 2. Consumer space conversions required. Color space conversion of equipment that supports composite video or analog digital signals is still preferable to D/A (digital-to-analog) YPbPr video usually uses technique 3. conversion followed by A/D (analog-to-digital) conver- For digital video, either technique 1 is commonly used sion, hence the positioning of HDMI RGB above analog or timing code words are embedded within the digital YPbPr. video stream. The computer industry has standardized on analog and digital RGB for connecting to the computer monitor. Interlaced VS. progressive Since video is a series of still images, it makes sense to Video timing simply display each full image consecutively, one after the another. Although it looks like video is continuous motion, it is This is the basic technique of progressive, or non- actually a series of still images, changing fast enough that interlaced, displays. For progressive displays that it looks like continuous motion, as shown in Figure 7.1-1. "paint" an image on the screen, such as a CRT, each This typically occurs 50 or 60 times per second for image is displayed starting at the top left corner of t