7.1 Introduction

It should be borne in mind that however exciting it may be, MPEG is only a technology. Technology per se is not useful and only becomes useful when it is incorporated into an appropriate and affordable product or service. If the use is not appropriate or affordable, there is no point in blaming the technology.

In this chapter a number of useful applications of MPEG are outlined. In each case designers have followed the rules of high technology to design systems which maximize the potential of the technology whilst protecting against its weaknesses.

MPEG is an information technology. It cannot deliver anything physical: you get the movie but no popcorn. The strength of MPEG is that it delivers audio-visual material with economy of bandwidth. Its weaknesses are sensitivity to bit errors and the requirement for near-real- time transmission. The variable-length coding of MPEG can lose synchronization in the presence of a single bit error. Decoders can take a considerable time to recover from a buffer underflow or overflow.

Wherever bandwidth or storage capacity is in short supply, MPEG is useful. Where bandwidth is plentiful, as in optical fibre networks, MPEG is pointless. As the capacity and economics of storage devices continue to increase, MPEG becomes less important.

MPEG will remain important in any area where there will be a permanent shortage of bandwidth; this includes any mobile equipment or service which must use radio communication.

Figure 7.1 shows that well-engineered applications of MPEG will always include an...