Designing Internetworks for Multimedia
As Table indicates, the storage formats deliver different lines of resolution. Resolution is a measure
of an image’s quality. From the viewer’s perspective, an image with higher resolution yields sharper
picture quality than a lower resolution image.
Most consumer televisions display roughly 330 lines of horizontal resolution. Broadcast
environments typically used high-end cameras to capture video. These cameras and their associated
storage formats can deliver horizontal resolutions of approximately 700 lines. Each time a copy is
made, the copied image loses some of its resolution.When an image is recorded in high-resolution,
multiple generations of the video can be copied without a noticeable difference. When an image is
recorded in a lower resolution, there is less room to manipulate the image before the viewer notices
the effects.
Digitizing video involves taking an analog video signal and converting it to a digital video stream
using a video capture board, as shown in Figure 13-4. Today, a variety of computer platforms,
including PC, Macintosh, and UNIX workstations, offer video capture capabilities. In some cases,
though, the capture equipment is a third-party add-on. The analog video source can be stored in any
video storage format or it can be a live video feed from a camera. The source can be connected to
the video capture card using any three connectors types (component, S-Video, or composite)
depending on the connector type that the card supports.
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