Program Specific Information (PSI) is normative program information in DigitalVideo Broadcast, DVB-PSI, for demultiplexing the transport stream( TS) and for regenerating the various digital TV programs.
The PSI tables of MPEG-2 describe how the Elementary Streams( ES) must be combined to build the program. Each individual PSI table is transmitted section by section in short data packets of variable length and protected by a checksum(CRC). This program specific information is similar to the Video Programming System ( VPS) information for video recording control.
The Program Specific Information (PSI) is used by the DVB receiver to be able to decode the data stream at all. It contains all the necessary information about the services belonging to the program, which can be television, radio or data.