Distinction of program streams and transport streams within MPEG-2 systems and PES packets as a common layer to carry content in both. Forming a program stream from PES packets. The structure of a transport stream and the use of transport packets. Navigation information on multiple programs and streams in a transport stream. Carriage of PES packets in transport packets. Consideration on the size of a transport packet. The use of sections for carrying information in a transport stream, and how to convey sections in transport packets.