ABSTRACT
This chapter focuses on the nature of the transportation systems that will be used to carry television signals in the new world of Advanced Television. Looking at television applications, packets separate and package the various forms of data such as video, audio, and associated or "private" data for sending them from their source encoders to their corresponding source decoders. The packet headers provide identification of the contents of the packets along with necessary synchronization. The moving pictures expert group (MPEG)-2 packet structure exists at what is termed the "systems layer" of the MPEG-2 scheme. At the most basic level of the MPEG-2 systems layer are packetized elementary streams (PESs) that carry one source of data for one application. Adaptation headers always follow a transport stream header and subtract from the 184 byte space available for the PES payload in the packet in which they are carried.
