Glossary

5C See digital transmission content protection (DTCP).

8-bit color With 8-bit color, the color in a picture is derived from 256 colors. Thus, only 256 colors are available to be used in a single picture when using 8-bit color.

64QAM 64QAM stands for 64-state Quadrature Amplitude Modulation. 64QAM is the Digital Video Broadcasting (DVB) specified modulations standards for digital cable transmission.

720p 720p is a High Definition Television (HDTV) format with 1280 active horizontal pixels and 720 active scanning lines and using progressive scanning.

1080i 1080i is a High Definition Television (HDTV) format with 1920 active horizontal pixels and 1080 active scanning lines and using interlace scanning.

AC-3 See Dolby AC-3.

active application An application in the active state is loaded into the set-top box’s memory and runs in the foreground.

Advanced Television Enhancement Forum (ATVEF) The Advanced Television Enhancement Forum (ATVEF) is a consortium of broadcast, cable, and computer companies founded in 1998 that developed the ATVEF Enhanced Content Specification, an HTML and JavaScript-based format for adding content to interactive television. ATVEF closed at the end of 1999 and turned over the specification to the ATV Forum and Society for Motion Picture and TV Engineers (SMPTE). ATVEF’s primary area of interest was interactive television. One aim was to aid in extending the Internet to broadcast media. ATVEF-compliant systems do not need to be fully digital and thus can include the use of the Vertical Blanking Interval (VBI).

Advanced Television Systems Committee (ATSC) The Advanced Television Systems Committee (ATSC) was established in 1983 to develop voluntary technical standards, including interactive television systems and digital high definition television (HDTV). The ATSC is usually thought of as a committee to address the needs of the North American television market. The ATSC standard for HDTV was approved in 1995 and adopted—with the  exception of the mandatory video formats section—by the Federal Communications Commission (FCC) in 1996. It is to replace the analog National Television Systems Committee (NTSC) format in North America.

AIF See audio interchange file (AIF).

American National Standards Institute (ANSI) The American National Standards Institute (ANSI) is an organization that works to develop a consensus on a general range of standards for use in the United States. ANSI is not a governmental organization.

ANSI See American National Standards Institute (ANSI).

API See application programming interface (API).

applet An applet is a small Java program that you can embed in Hypertext Markup Language (HTML) pages. Applets, in contrast to full-fledged Java applications, are not allowed access to certain resources on the local computer, such as files and devices including modems, printers, etc. An applet is designed to do a specific and limited task.

application An application implements the services provided to the viewer. The term application is usually used in the context of the client and server software that is executed when a viewer selects a service.

application boundary An application boundary is a general description of the data elements—such as Hypertext Markup Language (HTML) documents, code files, images, etc.—used to form one application and the logical locator of the entry point. The application boundary is frequently described by a regular expression over the URL language.

application instance An application instance is a unique invocation of an application. That is, running the same application twice results in two distinct application instances.

application manager In general, an application manager manages the lifecycle of an application. For example, the application may initialize the resources needed for the application and release the resources when the application exits.

application platform An application platform is the collection of application program interfaces and protocols on which content and applications are developed. The MPE platform is one example of an application platform.

application programming interface (API) An application programming interface is a series of functions that applications can use to make the operating system perform specific tasks. APIs let you program without having intimate knowledge of the device or software to which you are sending commands. An API can consist of classes, function calls, subroutine calls, descriptive tags, etc.

application server An application server executes applications that are required to provide digital services to subscribers. In general, application servers may provide the following applications: virtual channel server, interactive program guide, Dynamic Host Configuration Tool (DHCT) configuration, pay-per-view, and Emergency Alert System (EAS) messaging.

ASI See asynchronous serial interface (ASI).

aspect ratio The aspect ratio describes the ratio of the picture width to the picture height on the television screen. In National Television Systems Committee (NTSC) and Phase Alternating Lines (PAL) video formats, which are used for conventional analog television, the present standard is 4:3. In wide screen video, the aspect ratio is most often 16:9, but may also be 14:9. In High Definition Television (HDTV), the aspect ratio is 16:9.

asset management system An asset management system contains a single, logical database of assets that defines metadata and asset relationships. An asset management system generally manages an asset’s lifecycle, the propagation of multiple replicated copies of content on content servers, as well as access of assets via access networks.

ATSC See Advanced Television Systems Committee (ATSC).

ATV forum The Advanced TV Forum is a membership association founded in 2000 that promotes interactive television. It supports the Enhanced Content Specification originally developed by the Advanced Television Enhancement Forum (ATVEF).

ATVEF See Advanced Television Enhancement Forum (ATVEF).

audio interchange file (AIF) Audio Interchange Format (AIF) is an audio file format developed by Apple Computer to store high quality sound and musical instrument files (data).

back end Back end refers to a program that handles details behind the scenes, performing tasks not directly controlled by the user. It also refers to the infrastructure of servers, databases, and software that supports the actions of users who interact with delivered content.

bandwidth Bandwidth refers to the measure of the capacity of a transmission channel or the difference between the highest and lowest frequency levels. Bandwidth is the information-carrying capacity of a communication channel. The amount of transmission capacity possessed by a system or a specific location in a system is also referred to as the bandwidth. A television channel occupies a bandwidth of 6 million cycles per second (6 MHz). Cable system bandwidth occupies 50 to 300 MHz on the electromagnetic spectrum.

banner A banner is a dynamic, on-screen display of information, superimposed over content, sharable among various applications authorized to do so at a given time. Items displayed in a banner may have interactive characteristics. There may be different banners for different purposes such as the volume indicator, program information, and alerts. All banners must be coordinated so that they do not conflict in position or content, and remain aesthetically pleasing.

basic cable Basic cable refers to the basic program services distributed by a cable system for a basic monthly fee. These include one or more local broadcast stations, distant broadcast stations, non-pay networks, and local origination programming.

BAT See Bouquet Association Table (BAT).

baud rate The baud rate is the measure of the speed of transmission of a digital code.

bouquet A bouquet is a number of product or services that are combined and then marketed as only one product or service.

Bouquet Association Table (BAT) A Bouquet Association Table provides information regarding bouquets. It gives the name of the bouquet and provides a list of services for each bouquet.

broadcast file system (BFS) A broadcast file system is a data carousel system by which application data can be stored on an application server and transmitted frequently to the set-top boxes for application use. It controls a file and directory structure broadcast repeatedly in a carousel over the cable network.

cable modem termination system (CMTS) Located at the cable television system head-end or distribution hub, a cable modem termination system provides complementary functionality to the cable modems to enable data connectivity to a wide area network.

CAT See Conditional Access Table (CAT).

channel A channel is the transmission path between two points. The term channel may refer to a one-way path or a two-way path. A two-way path is when paths in the two directions of transmission are always associated. It is usually the smallest subdivision of a transmission system by means of which a single type of communication service is provided—that is, a voice channel, a teletypewriter channel, or a data channel.

channel-based application A channel-based application launches automatically—bypassing the default service menu—when a subscriber tunes to a specifically configured individual channel. In these cases, the application is considered an integral part of the channel, but the service menu is still  available.

channel capacity The channel capacity refers to the number of channels available for current or future use on a cable system.

client The client generally refers to the set-top box located at the subscriber’s premises.

closed captioning In analog television, closed captioning are subtitles for the hard of hearing and the deaf. The subtitles are transmitted as digital data in the vertical blanking interval (VBI). With closed captioning, the dialogue and sounds in the programming and news are displayed on the television screen. The text is in/on line 21 of the vertical blanking interval.

CMTS See cable modem termination system (CMTS).

conditional access Conditional access systems restrict television program access to certain groups of users either because of concerns for privacy or the desire to collect revenue for the service. Providing conditional access requires secure encryption of the program content, secure decryption in a set-top box for each viewer, and an embedded serial number that is registered in a central conditional access system database. Cable television systems have employed a variety of conditional access systems over the years, many of which have been broken by pirates. The newest approach is to embed the decryption technique in a credit-card-sized point of deployment (POD) module that can be replaced if the system security is compromised. This approach is much more cost effective than replacing the entire set-top box.  Smart cards and/or a private PIN number are most often used to access the services, and/or premium services, by the end-user. The system is primarily made up of three parts:

• signal scrambling
• encryption of electronic keys that the viewer will need
• subscriber management system, which ensures those who have bought the scrambled programming are able to receive and watch it.

conditional access and encryption Conditional access and encryption refers to the system that provides selective access to programming to individual customers in exchange for payment.

Conditional Access Table (CAT) The Conditional Access Table provides information about the conditional access systems used in the multiplex. The information is private and depends on the conditional access system. When applicable, it does include the location of the Entitlement Management Message (EMM) stream.

content Content is one component of an asset. For example, the content may be the physical MPEG file in a movie asset, the binary of an executable code asset, or the physical audio file in an audio asset. Content is different from an asset in that content does not have metadata; it represents only the bits of the component itself.  In the more general broadcasting context, content is movies, shows, advertising, or sports—any programming streamed to the viewer. 

content owner The content owner owns the intellectual property rights in the content.

content protection Content protection is a mechanism to protect the unauthorized copying of video and audio programming.

content provider In the case of interactive television, the content provider is the entity that literally sends the viewer the television signal—or shows—they watch. Content providers most often are local network television stations affiliates, cable television providers, and/or satellite television providers.

content server A content server is a device used for storing content within an asset management region. Content is loaded onto a content server via a propagation network. The output of a content server may be either via a propagation network, an access network, or both.

DASE See Digital Applications Software Environment (DASE).

Data Over Cable Service Interface Specifications (DOCSIS) Data Over Cable Service Interface Specifications (DOCSIS) is a specification for transmission of data over a cable network that has been approved by the International Telecommunications Union (ITU) as an international standard. DOCSIS was developed by CableLabs and a consortium of North American multi-system cable operators.

DAVIC See Digital Audio Visual Council (DAVIC).

DBS See direct broadcast satellite (DBS).

decoding time stamp (DTS) A decoding time stamp is a field that may be present in a Packetized Elementary Stream (PES) packet header that indicates the time that an access unit is decoded in the system target decoder.

dedicated playback channel A dedicated playback channel is used for playing reserved shows, displaying menus, etc. This channel is not used for broadcast content.

demultiplexing Demultiplexing refers to separating data streams or individual channels of data from a single, multiple channel stream. For example, video and audio streams must be demultiplexed before they are decoded. This is true for muliplexed digital television transmissions. The set-top box or built-in must demultiplex the signal it receives before it can be watched.

DHCP See dynamic host configuration protocol (DHCP).

DHEI See digital head-end extension interface (DHEI)

Digital Applications Software Environment (DASE) The Digital Applications Software Environment (DASE) is a subcommittee of the Advanced Television Systems Committee (ATSC) seeking to standardize and deploy technologies for enhanced television. The DASE standard provides a higher level of functionality than ATVEF and requires a more powerful enhanced television receiver including a Java run-time engine. The DASE standard is similar in features and scope to the DVB-MHP standard.

Digital Audio Visual Council (DAVIC) The Digital Audio-Visual Council (DAVIC) is a non-profit organization established in Switzerland. DAVIC created complete sets of specifications using emerging digital audio-visual technologies. The DAVIC 1.3.1 set of specifications became an International Standard. It was closely associated with Digital Video Broadcasting (DVB) and several joint standards were developed.

digital compression Digital compression is an engineering technique for converting a cable television signal into a digital format which may then be processed in a manner that requires a smaller portion of spectrum for its transmission. This compressed format allows many channels to be carried in the bandwidth normally required for one signal. This format can also be easily stored and manipulated.

digital head-end extension interface (DHEI) The digital head-end extension interface is a proprietary GI MPEG-2 transport interface used by the GI Integrated Receiver Transcoder (IRT).

digital signal A digital signal is a signal that has a limited number of discrete states prior to transmission. This may be contrasted with an analog signal that varies in a continuous manner and may be said to have an infinite number of states.

digital signature The digital signature is the data element that binds a message or transaction to its originator to verify the integrity of the message or transaction.

Digital Storage Media-Command and Control (DSM-CC) Digital Storage Media-Command and Control (DSM-CC) is a toolkit for developing control channels associated with MPEG-1 and MPEG-2 streams. DSM-CC is defined as part of the MPEG-2 standard. It is designed for lightweight and fast operation to meet the needs of devices that contain limited memory, such as set-top boxes.

digital transmission Digital transmission is a mode of transmission in which all information to be transmitted is first converted to digital form and then transmitted as a serial stream of pulses. Any signal—voice, data, or television—can be converted to digital form.

digital transmission content protection (DTCP) Digital transmission content protection (DTCP) was jointly created by five companies: Hitachi, Intel, Matsushita (MEI), Sony, and Toshiba. DTCP defines a cryptographic protocol for protecting digital content from illegal copying, interception, and tampering as it traverses a digital interface, such as the one defined by the Institute of Electrical and Electronic Engineers (IEEE) 1394 standard. It is also known as 5C.

Digital Video Broadcasting (DVB) Digital Video Broadcasting is a European standard for digital television.

digital video recording (DVR) Digital video recording refers to the recording to a local disc in the set-top box.

Digital Video Subcommittee (DVS) The Digital Video Subcommittee is an American National Standards Institute (ANSI)-sponsored standardization committee of the SCTE.

Digital Visual Interface (DVI) The Digital Visual Interface (DVI) was developed to provide a standard
high-speed uncompressed digital interface between a personal computer and the growing number of Liquid Crystal Display (LCD) and plasma-based monitors. When combined with suitable digital content protection technology (HDCP), the DVI specification also provides the cable and consumer electronics industry with an improved method for connecting a digital set-top box to the digital television display device.

direct broadcast satellite (DBS) Direct broadcast satellite is a type of satellite technology that transmitsdirectly to the end user or customer. Direct broadcast satellite describes a frequency allocation and wide spacing between satellites that generally permits higher-powered transmissions through the air to small 18- to 24-inch receiving facilities located on customer premises—point-to-multipoint transport. Direct broadcast satellite is also known as direct-to-home (DTH) satellite.

DOCSIS See Data Over Cable Service Interface Specifications (DOCSIS).

DOCSIS 1.1 DOCSIS 1.1 is a version of the DOCSIS Media Access Control (MAC)-layer protocol standard, which contains quality-of-service (QoS) traffic management functions and BPI authentication extensions.

DOCSIS 2.0 DOCSIS 2.0 is the current version of the DOCSIS standard. DOCSIS 2.0 is backward-compatible with DOCSIS 1.0 and 1.1. It implements advanced physical-layer modulation and S-CDMA, allowing a significantly higher upstream channel capacity, as well as better noise immunity.

DOCSIS modem The Data Over Cable Systems Interface Specifications (DOCSIS) for cable modems were developed by CableLabs and standardized internationally.

Dolby AC-3 Dolby AC-3 refers to the audio encoding format adopted by the Advanced Television Systems Committee (ATSC) for its advanced television audio encoding. Dolby AC-3 is also known as Dolby digital.

DSM-CC See Digital Storage Media-Command and Control (DSM-CC).

DTCP See digital transmission content protection (DTCP).

DTS See decoding time stamp (DTS).

DVB See Digital Video Broadcasting (DVB).

DVI See Digital Visual Interface (DVI).

DVS See Digital Video Subcommittee (DVS).

dynamic host configuration protocol (DHCP) The dynamic host configuration protocol is an Internet protocol used for assigning network layer, Internet protocol (IP) addresses dynamically to IP hosts. When DHCP is used, whenever a computer logs onto the network, it automatically gets an IP address assigned to it.

ECM See Entitlement Control Message (ECM).

electronic program guide (EPG) An electronic program guide is an application that displays  television program information, including program name, start time, and duration. It is literally an onscreen guide that helps make it easier for viewers to choose and/or go to the large number of channels, Pay-Per-View (PPV) events, and shows available particularly in a digital environment. By using the electronic program guide, you can often also pay for events such as Video-on-Demand (VOD). More advanced electronic program guides offer Internet interactivity for browsing, chatting, e-mail, etc. Electronic program guides can also keep track of your favorite channels, offer a reminder service that lets you know when your favorite shows are coming on, restrict access to channels you do not want the kids to see, or offer a television search engine of a sort that can search for types of shows or themes in shows. When the customer starts up his or her set-top box, the electronic program guide probably is what comes up initially. Frequently, the content provider and/or the individual viewer can customize the electronic program guide.

element management system (EMS) The element management system contains software applications used for configuration, performance, and faults from one or more network elements. The element management system is a second layer of management in the telecommunications management network hierarchy.

elementary stream (ES) An elementary stream is a generic term for one of the coded video, coded audio, or other coded bit streams. One elementary stream is carried in a sequence of Packetized Elementary Stream (PES) packets with one and only one stream_id.

EMM See Entitlement Management Message (EMM).

emulator An emulator is a hardware or software device that simulates the action of something else. For example, a PC application that is intended to simulate the functionality of the middleware and related set-top box is an emulator.

encapsulation Encapsulation allows one network to send its data over another network’s connections. Tunneling works by encapsulating a network protocol in the packets carried by the second network.

encryption Encryption is a form of encoding transmitted data for security purposes. It normally requires the decryption key to decipher the transmission upon receipt. The level of security depends on the complexity of the key used.

encryption key An encryption key is an alphanumeric (letters and/or numbers) series that enables data to be encrypted and then decrypted so it can be safely shared among members of a network. Some wireless security systems use an encryption key that automatically encrypts outgoing wireless data. On the receiving side, the same encryption key enables the computer to automatically decrypt the information so it can be read.

Entitlement Control Message (ECM) Entitlement control messages are private conditional access information that specify control words and possibly other stream-specific, scrambling, and/or control parameters. The data does not necessarily have what would be considered more personal information, such as the number of months of service the viewer wants to pay for.

Entitlement Management Message (EMM) Entitlement management messages are private conditional access information that specify the authorization level or the services of specific set-top boxes. The information does not address options that activate what movie the viewer wants to see or what times the viewer wants to see it.

EPG See electronic program guide (EPG).

ETSI See European Telecommunications Standards Institute (ETSI).

ETV See educational television station (ETV).

European Telecommunications Standards Institute (ETSI) The European Telecommunications Standard Institute (ETSI) is the European equivalent of American National Standards Institute (ANSI).

FCC See Federal Communications Commission (FCC).

Federal Communications Commission (FCC) The Federal Communications Commission (FCC) is an agency that regulates communications services, including cable television, at the federal level. The FCC was established in 1934 by the Communication Act of 1934.

forward channel The forward channel is the direction of radio frequency (RF) signal flow away from the headend toward the end user. The forward channel is the equivalent to downstream.

forward data channel The forward data channel is a data channel carried from the head-end to the set-top box in a modulated channel at a typical rate of 1.5 to 8 Mbps.

front channel The front channel refers to the actual broadcast between the television content provider—which usually means television broadcaster, but not always—and the television viewer. Its characteristics are its high bandwidth—typically, 6 MHz—and its one-way nature. In non-interactive
television systems, the front channel is the only channel as the signal is only going to the viewer. But in interactive television, a back channel is also needed for the return flow of data from the viewer.

front end The front end is the first radio-frequency amplifier stage on a receiver. This is one of the most critical components of the receiver because the sensitivity of the front end dictates the sensitivity of the entire receiver.

H.263 H.263 is a standard for variable low bit rate coding of video. H.263 can be better than MPEG-1/MPEG-2 for low resolutions and low bit rates.

HAVi HAVi is a software-based on the Institute of Electrical and Electronic Engineers (IEEE) 1394 standard that can make it possible for connections and integration of home entertainment devices, such as set-top boxes with other electronic appliances on a network, particularly a home networking system.

HBI See horizontal blanking interval (HBI).

HDCP See high-bandwidth digital content protection (HDCP).

HDTV See high definition television (HDTV).

HDTV quality ITU-R Recommendation 1125 defines HDTV quality as the delivery of a television picture which is subjectively identical with the interlaced HDTV studio standard.

headend The headend is the control center of a cable television system, where incoming signals are amplified, converted, processed, and combined into a common cable along with any original cablecasting, for transmission to subscribers. The system usually includes antennas, preamplifiers, frequency converters, demodulators, modulators, processors, and other related equipment.

headend router The headend router is the computer, at the cable head-end, responsible for gateway operations between the head-end and the internet.

HFC See hybrid fiber coax (HFC).

high-bandwidth digital content protection (HDCP)The high-bandwidth digital content protection (HDCP) specification was developed for protecting digital entertainment content that uses the Digital Visual Interface (DVI). HDCP encrypts the transmission of digital content between the video source or transmitter—such as a computer, DVD player, or set-top box—and the digital display, or receiver—such as a monitor, television, or projector.

high definition television (HDTV) High definition television refers to a television signal with greater detail and fidelity than the current television systems used. The United States currently uses a system called National Television Systems Committee (NTSC). HDTV provides a picture with twice the visual resolution in both the horizontal and vertical dimensions and a picture aspect ratio of 16:9 as well as CD-quality audio.

Home AV Interoperability (HAVi) See also HAVi, which is the more common name.

horizontal blanking interval (HBI) The horizontal blanking interval is an unused gap in a television signal that occurs before each line of a picture. This is not the same as the vertical blanking interval.

hybrid fiber coax (HFC) Hybrid fiber coax is a type of network that has both copper coaxial cables and fiber-optic cables. Cable television is evolving into cable telecommunications. Cable multiple system operators (MSOs) throughout the world are upgrading coaxial cable systems to hybrid fiber coax cable networks to deliver high-speed data and Internet service, cable telephony or competitive local exchange service, and digital multimedia services, along with multiple channel television. 

ICG See interactive cable gateway (ICG).

I frames I frames are one of the three types of frames that are used in MPEG-2 coded signals. The other two are B frames and P frames. It is MPEG-2 still pictures.

impulse pay-per-view (IPPV) Impulse pay-per-view (IPPV) is a movie rental service similar to pay-per-view (PPV). However, IPPV allows the customer to purchase the right to view the movie or event through an on-screen interface.

in-band channels In-band channels provide service-related broadcast information, subscriber tunable channels, and hidden channels.

in-band data QAM An in-band data QAM is a QAM that supports the 10Mbps data circuit that the DNCS uses to broadcast in-band data to the set-top box.

Integrated TVs Integrated TVs offers multiple features, such as PC components, high definition monitor, HDTV reception, hard drive, remote keyboard, etc. Integrated TVs are also known by other names, including PCTVs, computer televisions, integrated smart televisions, etc.

interactive advertising Interactive advertising most often takes the form of television commercials that offer isolated link areas—which may be referred to as triggers, rollovers, or hot spots—that are viewed along with the television program. Viewers can click on these links using a control device such as a remote control, mouse, or keyboard, and experience more of the commercial than those who see the commercial without these enhancements. An example is when a commercial is aired and a link to the advertiser’s web site is presented as part of the commercial, the viewer then could immediately click on the link(s) on the advertisement to go there. Viewers of that same advertisement, who do not have interactive television capacity, would not see those link areas. Interactive advertising is expected to be among the fastest growing segments of interactive television.

interactive cable Cable systems that have the technical ability to let subscribers communicate directly from their television sets to a computer at the system head-end using special converters and regular cable lines are referred to as interactive cable systems. Viewers can take advantage of services like movies-on-demand (MOD) and video-on-demand (VOD), as well as participate in targeted, interactive advertising from their home.

interactive cable gateway (ICG) The interactive cable gateway refers to the conversion point from the core network to the hybrid fiber coaxial (HFC) transport network. Core connections are terminated and MPEG-2 transport streams are reconstructed.

interactive channel browser An interactive channel browser, or channel browser, refers to a screen that comes up on the television screen and contains thumbnail size—roughly the size of big stamps—views of what is on each channel at that moment. The viewer, using the remote control can choose which channel he or she wishes and the sound and other channel information will come on for that channel.

interactive program guide (IPG) An interactive program guide is similar to an electronic program guide (EPG), but with increased interactive features, such as allowing users to sort through onscreen television listings by time, or channel, or themes, like children’s shows, and program a VCR or television directly from within th guide.

interactive television (iTV) Interactive television refers to a combination of television and interactive content and enhancements. Interactive television provides a richer entertainment experience as well as information, blending traditional television viewing with some of the interactivity of a PC. Interactive television features can include richer graphics, Internet access, email, chat, instant messaging, home shopping, home banking, interactive games, on-demand services such as weather and financial information, pay-per-view (PPV), and video-on-demand (VOD).

interlacing Interlacing refers to the television display format, where horizontal lines of pixels are illuminated in an alternating pattern rather than sequentially.

IPPV See impulse pay-per-view (IPPV).

IPG See interactive program guide (IPG).

ISA See industry standard architecture (ISA).

ISO See International Organization for Standardization (ISO).

ITU See International Telecommunications Union (ITU).

iTV See interactive television (iTV).

MHP See Multimedia Home Platform (MHP).

middleware Middleware is a general term for any programming that serves to glue together or mediate between two separate and usually already existing programs. It typically includes an application manager, a virtual machine, an interactive engine, libraries, and databases. In terms of interactive television, the middleware is often the software that provides services that occur between the server and end-user. This includes software that connects two separate applications together. This is particularly necessary as a number of different programs, platforms, and software are in use that are all oriented to the same goal of providing interactive television.

MP3 See MPEG Layer-3 Audio (MP3).

Moving Picture Experts Group (MPEG) The Moving Picture Experts Group is an international standards-setting group, working to develop standards for compressed full-motion video, still image, audio, and other associated information. MPEG is sufficient for all the major television standards, including National Television Systems Committee (NTSC) and high definition television (HDTV).

MPEG data stream An MPEG data stream is a multi-program data stream of interleaved and encoded data, video, and audio.

MPEG Layer-3 Audio (MP3) MP3 requires that downloaded files be sent to the user’s PC in their entirety before they can be played. Streaming, which starts playing before the download is finished, is the opposite of MP3.

MPEG program number An MPEG program number is the number associated with a specific program located within an MPEG-2 data stream.

MPEG splicing MPEG splicing refers to the ability to cut into an MPEG bit stream for switching and editing.

MPEG transport stream ID TBD

MPEG-1 MPEG-1 is a standard for coding moving pictures and associated audio for digital storage media up to about 1.5 Mbps. MPEG-1 quality is comparable to VHS video. This standard is designed to work at 1.2 Mbps, which is the data rate of CD-ROMs, thus the video could be played from CDs. The quality, however, is not sufficient for television broadcast. MPEG-1 is usually used by interactive television content developers for television stills (pictures with no motion).

MPEG-2 MPEG-2 is an improved video compression standard over MPEG-1 that offers better resolution at the same 30 frames per second as MPEG-1. MPEG-2 supports field and frame-based coding, which is critical for 60 fields-per-second interlaced video formats. It also supports a range of resolutions and aspect ratios, and bilateral interpolation (that is, B-frames). MPEG-2 is commonly used by cable television operators and direct broadcast satellite providers to offer digital video services because of its efficient use of capacity, improved quality over analog, and stereo sound.

MPEG-4 MPEG-4 builds on MPEG-2 by allowing for greater use of multimedia/graphics within the video stream and for better compression. The MPEG-4 standards are for use in digital television, interactive graphics, and interactive multimedia—which includes video. MPEG-4 is expected to be a major standard in the interactive television realm. MPEG-4 delivers video quality as good as MPEG-2 at about one-third less the bit rate.

MSO See multiple systems operator (MSO).

multimedia cable network system (MCNS) The multimedia cable network system created the Data over Cable System Interface Specification (DOCSIS) standard for cable transmissions.

Multimedia Home Platform (MHP) The Multimedia Home Platform is an emerging standard platform for interactive television. It consists of an MHP viewer terminal, including all possible low-to-high functionality implementations, its associated peripherals, and the in-home digital network. MHP can support many content types, not just HTML and JavaScript.

National Cable and Telecommunications Association (NCTA) The National Cable and Telecommunications Association —formerly, the National Cable Television Association—is a trade association for the cable television industry. NCTA provides its members with a strong national presence by providing a single, unified voice on issues affecting the cable and telecommunications industry.

National Television Systems Committee (NTSC) The National Television Systems Committee (NTSC) is responsible for setting television and video standards in North America. The NTSC standard for television defines a video signal with a refresh rate of 60 half-frames (interlaced) per second. The format is 525 lines in a 4-MHz video bandwidth. All television sets sold in North America are compatible. The NTSC standard is incompatible with most computer video standards, which generally use RGB video signals. However, special video adapters are available for computers to convert NTSC signals into computer video signals and vice versa.

native application In OCAP, a native application is an application written in or compiled to the machine code for the particular processor. Typically, it is written in C C++, or assembly language and may be supplied with the OCAP implementation or downloaded over the cable.

NCTA See National Cable and Telecommunications Association (NCTA).

Network Operations Center (NOC) The network operations center is a large group that is responsible for the day-to-day operations and maintenance of a network.

network operator A network operator is an organization, though generally a business, from which a network’s telecommunications are supervised, monitored, and maintained. This can include where cable and satellite signals are transmitted from. It does not necessarily include where the interactive television content was actually created, but it may if the organization is the content provider as well as the network operator.

NTSC See National Television Systems Committee (NTSC).

NVOD See near-video-on-demand (NVOD).

OCAP See OpenCable™ Application Platform (OCAP).

one-to-one advertising One-to-one advertising is geared towards a more

OOB channel See out-of-band (OOB) channel.

OpenCable™ OpenCable is an initiative led by CableLabs for its members, seeking to set a common set of requirements for interoperable digital set-top boxes, television receivers and other advanced digital devices manufactured by multiple vendors. These devices would be able to deliver digital video, data, and interactive services to a television set.

OpenCable™ Application Platform (OCAP) The OpenCable Application Platform is a software interface specification that completely defines the OpenCable host software interface that executes OpenCable portable, interactive applications, and services. OCAP is a separate effort from the Advanced Television Enhancement Forum (ATVEF) content specification, but OCAP does call for support and extension of ATVEF as a part of the presentation engine (PE) requirements.

OpenCable™ device An OpenCable device is an OpenCable-compliant digital set-top box or digital television receiver that allows the reception of existing cable television channels and provides the user interface for future, interactive applications.

out-of-band (OOB) channel An out-of-band channel is the combination of the forward and reverse out-of-band communications channels. The OOB channel provides an IP-based communication channel between the network and the digital set-top box.

P frames P frames are one of three types of frames used in the compressed (coded) MPEG-2 signal.

Pay-Per-View (PPV) Pay-Per-View refers to television programming for which cable subscribers pay a separate fee for each program viewed.

PCR See program clock reference (PCR).

personal video recorder (PVR) A personal video recorder is the hardware used by the consumer that is used both to digitally record and play back programming. You receive television like you normally do. The content provider—whether television networks, cable, satellite, etc.—sends the content—television shows, news, etc.—and you plug it into the set-top box. See also content provider.

personalized advertising In interactive television, personalized advertising is advertising geared towards a specific audience. Responses to the advertising can be measured, which can provide advertisers with a better understanding of what would sell and what would not. Interactive television can facilitate this. Demographics about the viewer are procured—at times without their knowledge— and advertising geared towards their expected interests are delivered to them by their content provider. The viewer is less likely to skip or delete this type of advertising. These advertisements might also be in the form of extended infomercials, which are programs of substantial length that are actually commercials.

personalized content In terms of interactive television, personalized content refers to content that could be standard programming or advertising, which is produced and presented to an audience that the content provider thinks would have more interest in it than the general masses. The content may be information the end-user has asked for or is data that is in the same general category of what a group of end-users have previously shown a pronounced interest in.

POD See Point-of-Deployment (POD) module.

Point-of-Deployment (POD) module A Point-of-Deployment (POD) module is a removable security module—in a PCMCIA or PC card form factor—which, when inserted in an OpenCable certified set-top box, television, or other device, enables delivery of digital video programming and other services. The OpenCable specification is designed in part to support the retail sale of advanced digital set-top boxes and other devices. Cable operators will provide PODs directly to customers who request them.

PPV See Pay-Per-View (PPV).

premium cable Premium cable is cable programming services for which subscribers pay an additional fee above the basic cable service charge. It is also called pay cable.

presentation engine (PE) In OCAP, the presentation engine is responsible for the appearance of information on the user interface (the display), and enables content to be displayed on a variety of devices. The presentation engine incorporates native code that decodes text (HTML, ECMAScript) into meaningful operations, and uses web-based software from the computer world, the web browser. However, the presentation engine has only limited ability to perform complex logic and arithmetic operations and lacks the security of the execution engine, which is why the execution engine is also required by OCAP.

Presentation Time-Stamp (PTS) The presentation timestamp is a field that may be present in a Packetized Elementary Stream (PES) packet header that indicates the time that a presentation unit is presented in the system target decoder.

program clock reference (PCR) The program clock reference is the time stamp in the transport stream from which MPEG decoder timing is derived.

program non-duplication Under Federal Communications Commission (FCC) rules, a cable system must black-out the programming of a distant television station it carries, when the system would duplicate a local station’s programming, on the request of the local station. This is referred to as program non-duplication.

program stream In MPEG-2, a program stream is a multiplex of variable-length digital video and audio packets from one or more program sources having a common time-base.

Program-Specific Information (PSI)
In MPEG-2, program-specific information is normative data necessary for the demultiplexing of transport streams and the successful regeneration of programs.

PSI See Program-Specific Information (PSI).

PTS See Presentation Time-Stamp (PTS).

PVR See personal video recorder (PVR).

QAM See quadrature amplitude modulation (QAM).

QPSK See quadrature phase-shift keying (QPSK).

quadrature amplitude modulation (QAM) Quadrature amplitude modulation (QAM) is a method of modulating digital signals onto a radio-frequency carrier signal involving both amplitude and phase coding. QAM is a modulation scheme used by telecommunications providers. More advanced modulation offers increased capacity—for example, 256 QAM offers greater capacity/transmission speeds than 64 QAM.

quadrature phase-shift keying (QPSK) Quadrature phase-shift keying is a method of modulating digital signals onto a radio-frequency carrier signal using four phase states to code two digital bits. It is used for transmitting digital signals over an analog medium.

reference platform A reference platform is the basic underlying architecture—hardware and middleware and software when applicable. Original equipment manufacturer (OEM) businesses can add to the reference platform proprietary software and other enhancements to make the product identifiable as theirs and function to their specifications.

resident application A resident application is an application or program that is built into the memory of the set-top box. These are updated, often automatically, by the service provider via the data stream (signal) that the set-top box receives from the service provider.

resident program guide The resident program guide is the program guide, most likely an electronic program guide (EPG) or an interactive program guide (IPG), that the interactive system offers the viewer. It could be based in the set-top box or at the server.

RF See radio frequency (RF).

satellite provider A satellite provider is the business that provides and probably maintains the actual hardware and equipment, including the satellites, to make the actual transmission to the viewer possible. The satellite provider does not necessarily provide the receivers that are used by the end-user.

satellite receiver The satellite receiver is the tuner portion of your satellite entertainment system. It is the part that takes commands from your remote control.

SDTV See standard definition television (SDTV).

second audio program (SAP) In an ATSC-encoded television sound carrier, a second monophonic audio stream—typically in a second language—delivered on the right channel of a stereo broadcast.

service list A service list is a list of services from the service information (SI) database that have a given service type. A service list has an internal pointer to keep track of your location within the service list.

set-top box A set-top box refers to any of several different electronic devices that may be used in a customer’s home to enable services to be on that customer’s television. If the set-top box device is used only for extending the channels available, it is called a converter. If it restores scrambled or otherwise protected signals, it is a descrambler.

standard definition television (SDTV) The term standard definition television is used to signify a digital television system in which the quality is approximately equivalent to that of National Television Systems Committee (NTSC). This equivalent quality may be achieved from pictures sourced at the 4:2:2 level of ITU-R Recommendation 601 and subjected to processing as part of the bit rate compression. The results should be such that when judged across a representative sample of program material, subjective equivalence with NTSC is achieved. Standard definition television is also called standard digital television.

stream A stream is an ordered series of bytes. The usual context for the term stream is the series of bytes extracted from transport stream packet payloads that have a common, unique PID value—for example, the video Packetized Elementary Stream (PES) packets or Program Map Table (PMT) sections.

streaming media Streaming media refers to the digital video, audio, and data services that are selectively delivered to individual users, either in response to a user request or based upon a user profile. These services are delivered over a data transport stream, either via real-time transmission to the user, or via off-peak data-carousel transmission to a storage device at or near the user’s location for subsequent retrieval.

switched digital video (SDV) Switched digital video refers to the technology for sending, up on request, video through cable television or telephone lines.

t-commerce Television commerce, or t-commerce, is an interactive television application that enables electronic transactions between businesses and consumers via television.

thick client Thick client refers to the concept of robust computer processing power, storage, and memory within the end users set top box or PC client. Software application(s) can and usually reside at the users location. Thick clients are also refered to as heavy clients.

thin client Thin client refers to the concept of minimizing required storage, memory, and computing horsepower at the user location by performing computing and storing information in a central location, with connections for user input and display over a medium-speed network.

transport stream In MPEG-2, the transport stream refers to a packet-based method of multiplexing one or more digital video and audio streams having one or more independent time bases into a single stream.

trigger A trigger is an event that may cause a change in the behavior of a DVB-HTML application that registers interest in such events. Triggers may come from many sources—for example, the broadcast stream—or may be generated from other data such as the system clock, or may be generated as a result of user interaction.

tune From the viewer’s standpoint, tune means to select a channel—for example, tune to channel 9. This term stems from analog broadband systems, but is such a familiar term that it would seem best to keep it, even though it is no longer accurate.

two-way Two-way refers to bidirectional communications over the same communication medium.

two-way capacity A cable television system with two-way capacity can conduct signals to the head-end as well as away from it. Two-way or bi-directional systems now carry data. Eventually, these systems may carry full audio and video television signals in either direction.

VBI See vertical blanking interval (VBI).

VCT See Virtual Channel Table (VCT).

velocity of propagation Velocity of propagation refers to the velocity of signal transmission. In free space, electromagnetic waves travel with the speed of light. In coaxial cables, this speed is reduced. The velocity of propagation is commonly expressed as percentage of the speed in free space.

vertical blanking interval (VBI) The vertical blanking interval is the unused lines in each field of a television signal, seen as a thick band when the television picture rolls over. Some of these lines may be used for teletext and captioning, or may contain specialized data.

video Video generally refers to the bandwidth and spectrum of the signal that results from television scanning and which is used to produce a picture.

video-on-demand (VOD) Video-on-demand allows a subscriber to select movies he or she wishes to view from a large selection of titles and categories stored on a remote server at any time. This service may also provide VCR functionality—stop, pause, etc.—that allows the subscriber to control the play back of the server from the remote control.

viewer A viewer is the person currently in control of the set-top box. This term may just refer to whoever is holding the remote, but has other implications when viewer profiles are used.

viewer profile A viewer profile allows the viewing experience to be personalized for each viewer. Each viewer may have personal favorite channels and certain other settings. Some features, such as parental controls, may be extended to allow a personal viewing and purchasing PIN for each viewer.

viewer session Viewer session refers to all set-top box viewer activities between the start of a session and the end of a session. These events may be different, depending on whether individual viewer profiles are provided.

violence chip (V-chip) A V-chip is a microchip that permits parental control over rated television programs.

Virtual Channel Table (VCT) The Virtual Channel Table is broadcast by the head-end and read by the tuner manager during the boot process. The VCT is defined by the Advanced Television Systems Committee (ATSC). Basically, the VCT contains the following information:
◆ a transport stream identifier
◆ the channel number
◆ the short channel name
◆ the carrier frequency
◆ the program number
◆ the access controlled flag
◆ the location field for extended text messages
◆ the service type

virtual machine A virtual machine is an operating environment working with, yet independent of a host operating system. Used in such applications as a middleware component of a set-top box, virtual machines accommodate proprietary philosophies of associated software and service vendors.

VOD See video-on-demand (VOD).

voice-over-internet potocol (VoIP) Voice-over-internet protocol (VoIP) services are a provision of voice telephony via the use of packet-switched networks running Internet Protocol (IP) networks rather than traditional circuit switching. VoIP can be less expensive than voice transmission using standard analog packets over Plain Old Telephone Service (POTS).

VoIP See voice-over-internet potocol (VoIP).

wide screen Wide screen refers to a television signal with a wider picture of 16:9 aspect ratio instead of the conventional 4:3.