What to Look for in Computer Video Support

The following are some key video-support features to look for when purchasing a multimedia computer:

• Look for a balanced system in which each component has sufficient power. This is important because any of several components on the system could adversely affect the playback quality of a multimedia application. The computer might not have enough space on the CD-ROM or hard disk; the hard disk might not be able to retrieve data fast enough to play back well; the CPU might not have enough power to handle the decompression of the video; or the bus on the video display card might not be fast enough to move all of the data to the screen.
• Look for Super VGA resolution. The minimum resolution for a multimedia computer is VGA, which provides a 640x480-pixel image and 256 colors, also expressed as 8 bits per pixel (bpp). Microsoft recommends that a consumer system include at least a Super VGA display, which provides 800x600-pixel resolution with approximately 64,000 colors (16 bpp) for users working with complicated graphics.

  For example, suppose that you are playing a video segment with a shaded maroon background that includes one underwater scene, followed by a skydiving scene, followed by a city street scene. Each scene and its background has very different color qualities. At least one of the scenes or the background will not be displayed well if a full-color clip is translated to a 256-color display.

• Look for a video card with a DCI provider for better performance.
• Look for a computer with a double-speed or faster CD-ROM drive, which reads data from the CD-ROM at a rate of at least 300 kilobytes per second. This is the rate needed to have good-looking 320x240-pixel digital video clips playing at a reasonable frame rate with no undue screen compression. (Screen compression changes resolution, causing a grainy image. At extreme compression, for example, an image of a person might look instead like a bunch of blocks.)