ANSI CTA-775.2-A-2008 pdf download Service Selection Information for Digital Storage Media Interoperability
1. INTRODUCTION CEA-775-C [1 ] standardizes the IEEE 1 394 [3][4] High Performance Serial Bus interface for the Digital Television (DTV) receiver. A digital storage device such as a D-VHS or hard disk digital recorder may be used by the DTV or by another source device such as a cable set-top box to record or time-shift digital television signals. The present standard supports the use of such storage devices by defining Service Selection Information (SSI), methods for managing discontinuities that occur during recording and playback, and rules for management of partial Transport Streams. For purposes of digital storage, it is desirable that SSI is stored along with program audio/video/data material. SSI supplements the program material by describing one or more selected services. Information can include:
the name of the source channel (for example, the name and number of ATSC PSIP virtual channel)
the title of the selected program
a multi-lingual textual description of the program (optional)
the program duration
the start time of the original broadcast
any descriptors pertinent to the program, such as content advisories
the type of source (camcorder, broadcast source, etc.)
an optional reference to further descriptive information
When a digital recording that includes SSI is played back, channel name and program title information is available for display. If system time is also recorded, using the time of day, start time and duration data, playback equipment can display the time remaining in the program at any point during playback. When several services are present in the transport multiplex, SSI data can be used to support user selection of the desired program.
SSI may be provided in one of two possible formats: as an MPEG-2 compliant data structure defined in this standard called the Selection Information Table (SIT), or as Service Information tables compliant with the ATSC A/65C PSIP [2] standard. A device preparing an MPEG Transport Stream for recording may delete transport packets corresponding to unwanted programs or services, thus creating a partial Transport Stream. This standard discusses the necessary signaling required for proper construction of a partial TS.