ABSTRACT
This chapter starts by defining multicasting and looking at the technologies that make multicasting possible. Multicasting is a technique that permits transmitting several program streams in a single channel. Multicasting is made possible by the use of digital video compression (DVC). In a multicasting application, a number of sources are compressed in individual source coders, combined in a multiplexer, applied to a single channel coder, and sent through a single transmitter or record amp, into a single channel in the medium. There are two strategies for multiplexing several program streams together into a single channel. These are: fixed multiplexing, and statistical multiplexing. The use of digital video compression combined with multiplexing allows the sharing of channel capacity between several program sources. The use of different data rates for the different types of program streams that multiplexing permits only complicates this circumstance.
