Transport stream (TS) is specified in MPEG-2, and it is a standard format for transmission and storage of audio, video, and data, and is also employed in broadcast systems for instance ATSC and DVB. Transport stream specifies a container format encapsulating packetized streams, with error correction and stream synchronization features for maintaining transmission integrity in the event the signal is degraded.

The call of Transport Stream to Program Stream is really as follows. Firstly, PS is ideal for reasonably reliable media, for instance disks (like DVDs), while TS is ideal for less reliable transmission, namely broadcast. Further, Transport Stream transmissions may carry multiple Program Streams. Some Important Portions of a Transport Stream:

PID - Each table or elementary stream inside a transport stream is identified by a 13-bit packet ID (PID).

Program Specific Information(PSI) - There are 4 PSI tables: Program Association , Program Map, Conditional Access, and Network Information. The MPEG-2 specification does not specify the format of the CAT and NIT.

Programs - Transport stream has a concept of programs. Each program is described by a Program Map Table (PMT) which has a unique PID, and the elementary streams associated with that program have PIDs listed PMT.

PMT - Program Map Tables (PMTs) contain information about programs. For each program, there is one PMT.

PCR - To enable a decoder to present synchronized content, like audio tracks matching the associated video, at least once each 100 ms, or PCR is transmitted in the adaptation field of an MPEG-2 transport stream packet.

AT - Stands for Program Association Table. It lists all programs available in the transport stream.