MULTIMEDIA DEVELOPING

Video has been a major part of public consciousness for over 50 years. The emergence of the VCR and the increasing shift to use of cable television signals have created an open environment where video producers can rapidly distribute information to a larger number of consumers. The domains of video, computer systems, and communications services used to be quite distinct.

Requirements for full-motion video compression:

The MPEG standard is a generic standard designed to support a wide range of applications. This genericity places a special burden if all applications are supported by the same basic standard. To address this issue, the standard has been set up in a toolkit manner. As we noted earlier, it has been determined that, for the present, acceptable video quality can be achieved by providing a bandwidth of 1.5 Mbits/sec. a much higher bandwidth would be required for HDTV-quality video, which also includes the digital audio signal bandwidth.

The major impact of this rate is on storage as well as transmission. Both must be able to keep up with this rate for any kind of streaming operation to be successful. The typical storage media for multimedia components include CD-ROM, DAT, optical writeable disks, hard disks, and magnetic tape. It is assumed that for a wide range of applications, decompression does not happen at the point of storage; rather, It happens at either an intermediate point or the destination CPU.

Applications using MPEG standards can be symmetric or asymmetric. Symmetric applications, as defined earlier in this chapter, are applications that require essentially equal use of compression and decompression. Asymmetric applications require frequent decompression, but usually the compression is performed only once. For these applications, there is no real need for on-line input devices.