Program and System Information Protocol
Encyclopedia
Communications protocol
A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...
used in the ATSC digital television system for carrying metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
about each channel
Channel (communications)
In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...
in the broadcast
Broadcasting
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
MPEG transport stream of a TV station and for publishing information about television programs so that viewers can select what to watch by title and description.
What PSIP does
PSIP defines virtual channelVirtual channel
In telecommunications, a logical channel number , also known as virtual channel, is a channel designation which differs from that of the actual radio channel on which the signal travels....
s and content ratings, as well as electronic program guide
Electronic program guide
Electronic program guides and interactive program guides provide users of television, radio, and other media applications with continuously updated menus displaying broadcast programming or scheduling information for current and upcoming programming...
s with title
Title
A title is a prefix or suffix added to someone's name to signify either veneration, an official position or a professional or academic qualification. In some languages, titles may even be inserted between a first and last name...
s and (optionally) descriptions to be decoded and displayed by the ATSC tuner
ATSC tuner
An ATSC tuner, often called an ATSC receiver or HDTV tuner is a type of television tuner that allows reception of digital television television channels transmitted by television stations in North America, parts of Central America and South Korea that use ATSC standards...
.
PSIP can also send:
- the exact timeTimeTime is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
referenced to UTC and GPS time; - the [short_name], which some stations use to publish their callsign.
PSIP is defined in ATSC standard A/65, the most recent revision of which is A/65C, published in 2006. A/69 is a recommended practice for implementing PSIP in a TV station.
PSIP also supersedes the A/55 and A/56 protocol methods of delivering program guide information (which the ATSC has deleted). TV Guide On Screen is a different, proprietary system provided by datacasting
Datacasting
Datacasting is the broadcasting of data over a wide area via radio waves. It most often refers to supplemental information sent by television stations along with digital television, but may also be applied to digital signals on analog TV or radio...
on a single station, while PSIP is required, at least in the United States, to be sent by every digital TV station.
PSIP information may be passed through the airchain
Airchain
In broadcast engineering for radio or television, the airchain or transmission chain is the path or route an audio or video signal takes on its way through a radio station or television station.The airchain begins with cameras, microphones, CD players, turntables, telephone hybrids, video tape...
using proprietary protocols or through use of the XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
-based Programming Metadata Communication Protocol
Programming Metadata Communication Protocol
Programming Metadata Communication Protocol is a standard for use within digital television broadcast facilities for transfer of the source data used to generate electronic program guide listings and other program-related information...
(PMCP, or ATSC A/76) facility metadata scheme.
Included tables
- STT (system time table)¹ - current time, transmitted at least once per secondSecondThe second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
, with an accuracy of new time values within 1 second or better - MGT (master guide table)¹ - data pointerData pointerIn computer science, a pointer is a programming language data type whose value refers directly to another value stored elsewhere in the computer memory using its address...
s to other PSIP tables - TVCT (terrestrial virtual channel table)¹ - defines each virtual channel and enables EITs to be associated with the channel
- CVCT (cable virtual channel table) - assigns numbers to each virtual channel and enables EITs to be associated with the channel
- RRT (rating region table) - content ratings for each country (region) covered by the station, save the U.S., as that region is loaded into TV sets already
- EIT (event information table)¹ - titles and program guide data
- ETT (extended text table) - detailed descriptions of channels (Channel Extended Text Table or CETT) and aired events (Event Extended Text Table or EETT)
- DCCT (directed channel change table) - see below
- DCCSCT (directed channel change selection code table) - provides for the ability to update states, counties and program genres used in DCCT tables
¹ indicates a US FCC requirement
Directed channel change
The DCC function lets broadcasters tell a DTV receiver where to change, based upon the viewer's settings. This is most likely to be a ZIPZIP Code
ZIP codes are a system of postal codes used by the United States Postal Service since 1963. The term ZIP, an acronym for Zone Improvement Plan, is properly written in capital letters and was chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the...
or other postcode, which can select demographically-based programming to show, such as television commercials or weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
bulletin
Bulletin
Bulletin can refer to:Periodicals * The Bulletin, a now defunct Australian magazine* The Bulletin , an alternative weekly published in Montgomery County, Texas, United States...
s, possibly taken from an accompanying datacasting
Datacasting
Datacasting is the broadcasting of data over a wide area via radio waves. It most often refers to supplemental information sent by television stations along with digital television, but may also be applied to digital signals on analog TV or radio...
channel.
Implementation
Implementation
Implementation is the realization of an application, or execution of a plan, idea, model, design, specification, standard, algorithm, or policy.-Computer Science:...
of the DCC feature is entirely optional, and depends on development of receiver and decoder technology. For example, a digital video recorder
Digital video recorder
A digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...
could record commercials broadcast at other times for later replay, so that many more different commercials could be shown in different parts of a large metro area
Metro Area
Metro Area is a Brooklyn-based dance music production team composed of Morgan Geist and Darshan Jesrani.- History :Geist grew up in Wayne, New Jersey, while Jesrani is from upstate New York...
than can actually be transmitted at once.
External links
- ATSC Standard A/65: Program and System Information Protocol
- ATSC Standard A/76 Programming Metadata Communications Protocol (PMCP) for transmitting PSIP data between devices in a broadcast facility
- ATSC Recommended Practice A/69: Program and System Information Protocol Implementation Guidelines for Broadcasters
- http://www.etherguidesystems.com/help/sdos/atsc/Syntax/TableSections/Default.aspx: for online details of PSIP table sections