MHEG-5, or

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

/ IEC 13522–5, is part of a set of international standards relating to the presentation of multimedia information, standardised by the

Multimedia Multimedia is a form of communication that uses a combination of different content forms, such as Text (literary theory), writing, Sound, audio, images, animations, or video, into a single presentation. T ...

and

Hypermedia Hypermedia, an extension of hypertext, is a nonlinear medium of information that includes graphics, audio, video, plain text and hyperlinks. This designation contrasts with the broader term ''multimedia'', which may include non-interactive linear ...

Experts Group (MHEG). It is most commonly used as a language to describe

interactive television Interactive television is a form of Technological convergence#Media, media convergence, adding data services to traditional television technology. It has included on-demand delivery of content, online shopping, and viewer polls. Interactive TV i ...

services.

Characteristics

MHEG-5 is a licence-free and public standard for interactive TV middleware that is used both to send and receive interactive TV signals. It allows a wide range of TV-centric interactive services to be deployed. It is used by Freeview and

Freesat Freesat is a British free-to-air satellite television service, first formed as a joint venture between the BBC and ITV plc and now owned by Everyone TV (itself owned by all of the four UK Public broadcasting, public service broadcasters, BBC, ...

in the UK, Freeview in New Zealand, TVB in Hong Kong, Freeview in Australia, Saorview in Ireland and has been specified in South Africa. Recent work by the DTG in the UK has led to the development of the MHEG-5 Interaction Channel (MHEG-IC), which enables an extension of broadcast interactive services to be delivered via an IP connection. The principles behind the MHEG-IC are to provide a seamless viewer experience of broadcast delivered content augmented with content delivered over IP as an extension of the channel or network. Broadcasters have full editorial control of the user experience. The MHEG-IC gives access to streamed on-demand video content in addition to traditional text and graphics as well as the ability to support secure transactions. MHEG-5 is an object-based

declarative programming In computer science, declarative programming is a programming paradigm—a style of building the structure and elements of computer programs—that expresses the logic of a computation without describing its control flow. Many languages that ap ...

language which can be used to describe a presentation of text, images and video. An MHEG-5 application consists of a number of ''Scenes'' which the user of the application can move between. Each ''Scene'' lists the items of text and graphics to be presented and can contain blocks of procedural code which are executed in response to one of a predefined set of events such as keys being pressed, timers firing or content being successfully loaded into memory. These blocks of code consist of ''elementary actions'' which can perform operations such as changing the text displayed by a text object, or starting a video clip playing. MHEG-5 specifies a hierarchy of classes that are available to the application author. Unlike in object oriented languages, it is not possible for new classes to be defined. The standard defines two representations of MHEG applications, one of which is textual and the other is represented in ASN.1. Applications are normally written in the textual notation and then encoded into ASN.1 for interpretation by the MHEG ''engine''. MHEG-5 is suited to programming

interactive kiosk An interactive kiosk is a computer terminal featuring specialized hardware and software that provides access to information and applications for communication, commerce, entertainment, or education. By 2010, the largest bill pay kiosk network ...

s and

services.

Use in other standards

MHEG-5 has been selected as the mandatory interactivity engine for CI+ compliant TVs (and other CI+ devices).

Profiles and commercial roll-out

The MHEG-5 language itself is just that, a language. To be useful in any particular context, the language needs to be profiled. A broadcast profile of the language has been standardized by

ETSI The European Telecommunications Standards Institute (ETSI) is an independent, not-for-profit, standardization organization operating in the field of Information and communications technology, information and communications. ETSI supports the de ...

, forming ETSI standard ES 202 184.

United Kingdom

In the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, MHEG-5 is used to provide

interactive Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but mo ...

services for digital television such as the BBCs Ceefax replacement service, BBC Red Button. The full specification of how MHEG-5 is used in the context of the UK Freeview platform is the UK Profile of MHEG-5. MHEG is also used on

for its programming guide in addition to the DVB EIT, as opposed to the OpenTV platform used on Sky.

New Zealand and Australia

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, the same profile as in UK is used, with minor additions for the Maori language and its use of the ''guide'' key on ''certified'' Freeview receivers. The ''guide'' receiver key is used to activate the MHEG-5 programming guide; this however disables use of the more compatible and faster loading DVB EIT guide feature. In Australia, this guide practice was adopted for the phase 2 Freeview and VAST receivers referenced by the label ''Freeview EPG''.

Hong Kong

In Hong Kong, TVB has also selected MHEG-5 for interactive services available on its digital-only channels.

Ireland

Ireland has selected MHEG-5 (v1.06) middleware for interactive services as a recommended feature of its Minimum Receiver Requirements for DTT in Ireland.Minimum Receiver Requirements for DTT in Ireland v1.0
. The name for Ireland's free digital service is Saorview.

Class hierarchy

Note: You can download the PDF version of above image from http://mheg5.net/down/class.pdf.

References

External links

* {{DEFAULTSORT:Mheg-5 Interactive television IEC standards ISO standards Hypermedia Multimedia