System Information [EtherGuide Glossary]
The transport stream elements needed or that are useful to demultiplex and otherwise process the video, audio and data streams are called system information, although this term is not explicitly defined in MPEG-2 documents.
System Information can be sorted into two major classes: information useful primarily by receivers, and information useful primarily to viewers, listeners and data users. System Information always comprises MPEG-2 private table structures that are transmitted periodically on packet ids assigned for that purpose by a published specification or, where permitted, are specified by the broadcaster.
System information starts with MPEG-2 Program Specific Information (PSI), which can be constrained by MPEG-2 users such as ATSC, ARIB, DVB and SCTE, each of which also provides for or requires the use of system information specific to the user's protocols.
For ATSC-compliant broadcasters, system information is specified in ATSC A/65, is labeled PSIP, and follows constraints listed in ATSC A/53, the Digital Television standard. PSIP technology is mandatory per ATSC specifications, and an edition of the A/65 specification has been partially incorporated by reference in FCC regulations.
DVB-compliant systems generally observe the DVB-SI specification, which is published as EN 300468.
SCTE-compliant systems can, depending on needs and services, have a variety of SI specifications, including SCTE 54, SCTE 65 SCTE 57
MPEG-2 specified system-information is almost exclusively information useful only to receivers, while ARIB, ATSC, DVB and SCTE service information provide information useful to receivers and people.