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Unformatted text preview: ng concepts that involve movement. Although both animation
and video deal with the display of a sequence of images (frames) to generate an
effect of motion, but video typically deals with recording of a real-life event
produced by a device such as a digital video recorder. Like animation data, video
data also requires large storage space and needs to meet the real-time constraints
on retrieval, delivery, and display. Again, digital video compression or a
compromise in quality can be applied to reduce the storage requirement.
Video information travels in natural media in the form of light waves, which are
analog in nature. In order for the computer to be able to understand video
information, light waves must be converted from analog form to digital form.
Video camera is a transducer that is commonly used to convert light waves into
electrical signals. Conversely, monitor is a transducer that is commonly used to
convert electrical signals into light waves. Like audio, in case of video also the
transformation between analog and digital signals is achieved by A/D and D/A
conversions as shown in Figure 19.3. Analog-to-digital conversion of video also
involves the sampling and quantization of analog signals as already explained
before and shown in Figure 19.4. A multimedia computer system capable of
processing video information requires a video board (or video card), which is
equipped with A/D and D/A converters.
Video Display Technologies
As already mentioned before in this chapter (see Figure 19.2), an image is
represented as a collection of pixels, which are arranged as a two-dimensional
matrix. Each pixel is of the size of a small dot. Hence, an image can be thought of
as made up of horizontal lines, each a row of individual dots (pixels). To paint an
entire video image on a monitor screen, an electron gun illuminates every pixel as it sweeps across the screen, one line at a time, from left to right and from top to
bottom and then back on the top. This process, called raster scanning, has to be
repeated several tim...
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This document was uploaded on 04/07/2014.
- Spring '14