Advanced Common Application Platform
Encyclopedia
The Advanced Common Application Platform (ACAP) is intended to provide television
consumers with advanced interactive
services and offer content providers, broadcasters, cable and satellite operators, and consumer electronics manufacturers the technical details necessary to develop interoperable services and products.
As a middleware
specification for interactive applications, ACAP gives content and application authors assurance that their programs and data will be received and run uniformly on all brands and models of receivers.
Trial implementations have already been done in South Korea
by a consortium of organizations. In addition, an extensive ACAP demonstration was held at NAB2004
.
An ACAP application is a collection of information processed by an application environment to interact with an end-user or otherwise alter the stateof- the-application environment. ACAP applications are classified into two categories, depending on whether the initial application content processed is of a procedural or a declarative nature.
These categories of applications are referred to as procedural
(ACAP-J) and declarative
(ACAP-X), respectively. An example of an ACAP-J application is a Java
TV Xlet
composed of compiled Java byte codes in conjunction with other multimedia content such as graphics, video and audio. An example of an ACAP-X application is a multimedia document composed of XHTML
markup
, style rules, scripts and embedded graphics, video and audio.
An ACAP application need not be purely procedural or declarative. In particular, an ACAP-J application may reference declarative content, such as graphics, or may construct and cause the presentation of markup content.
Similarly, ACAP-X applications may use script content, which is procedural in nature. Furthermore, an ACAP-X application may reference an embedded Java TV Xlet.
The architecture and facilities of ACAP are intended to apply to broadcast systems and receivers for terrestrial broadcast and cable TV
systems.
In addition, the same architecture and facilities may be applied to other transport systems, such as satellite. ACAP is primarily based on the GEM
(Globally Executable Multimedia) home platform specification developed by the DVB consortium and DASE, developed by the ATSC.
Digital television
Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...
consumers with advanced interactive
Interactive television
Interactive television describes a number of techniques that allow viewers to interact with television content as they view it.- Definitions :...
services and offer content providers, broadcasters, cable and satellite operators, and consumer electronics manufacturers the technical details necessary to develop interoperable services and products.
The role of ACAP
In essence, ACAP makes it appear to interactive programming content that it is running on a so-called "common receiver." This common receiver contains a well-defined architecture, execution model, syntax and semantics.As a middleware
Middleware
Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...
specification for interactive applications, ACAP gives content and application authors assurance that their programs and data will be received and run uniformly on all brands and models of receivers.
Trial implementations have already been done in South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
by a consortium of organizations. In addition, an extensive ACAP demonstration was held at NAB2004
National Association of Broadcasters
The National Association of Broadcasters is a trade association, workers union, and lobby group representing the interests of for-profit, over-the-air radio and television broadcasters in the United States...
.
An ACAP application is a collection of information processed by an application environment to interact with an end-user or otherwise alter the stateof- the-application environment. ACAP applications are classified into two categories, depending on whether the initial application content processed is of a procedural or a declarative nature.
These categories of applications are referred to as procedural
Procedural programming
Procedural programming can sometimes be used as a synonym for imperative programming , but can also refer to a programming paradigm, derived from structured programming, based upon the concept of the procedure call...
(ACAP-J) and declarative
Declarative programming
In computer science, declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow. Many languages applying this style attempt to minimize or eliminate side effects by describing what the program should accomplish, rather than...
(ACAP-X), respectively. An example of an ACAP-J application is a Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
TV Xlet
Xlet
An Xlet is very similar to a Java applet and is originally introduced in Sun's Java TV specification to support applications for Digital TV. Though Xlet looks superficially different from other application models in Java such as applet and MIDlet, it is actually meant to be a generalization of such...
composed of compiled Java byte codes in conjunction with other multimedia content such as graphics, video and audio. An example of an ACAP-X application is a multimedia document composed of XHTML
XHTML
XHTML is a family of XML markup languages that mirror or extend versions of the widely-used Hypertext Markup Language , the language in which web pages are written....
markup
Markup language
A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts...
, style rules, scripts and embedded graphics, video and audio.
An ACAP application need not be purely procedural or declarative. In particular, an ACAP-J application may reference declarative content, such as graphics, or may construct and cause the presentation of markup content.
Similarly, ACAP-X applications may use script content, which is procedural in nature. Furthermore, an ACAP-X application may reference an embedded Java TV Xlet.
The architecture and facilities of ACAP are intended to apply to broadcast systems and receivers for terrestrial broadcast and cable TV
Cable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
systems.
In addition, the same architecture and facilities may be applied to other transport systems, such as satellite. ACAP is primarily based on the GEM
Globally Executable MHP
Globally Executable MHP is a DVB specification of a Java based middleware for TV broadcast receivers, IPTV terminals and Blu-ray players. GEM is an ETSI standard and an ITU "Recommendation...
(Globally Executable Multimedia) home platform specification developed by the DVB consortium and DASE, developed by the ATSC.