Multimedia home platform

from Wikipedia, the free encyclopedia

The Multimedia Home Platform ( MHP ) is a standard from the DVB project and specifies the transmission and display of interactive content in digital television based on the Java programming language .

The MHP enables both purely radio-based services (information pages (extended teletext ), games, program overviews, more complex EPGs, etc.) as well as interactive services that require an additional return channel (e.g. votes / quizzes, home shopping offers, etc.).

MHP does not serve:

  • for the transmission of program information (there is service information (DVB-SI) and electronic program guides ( EPGs ))
  • the encryption of content (special encryption systems have already been defined for this)
  • for playback of audio or video (the transmission of an audio or video signal is one of the standard functions of a television and no further transmission method is required)

MHP-based applications can be transmitted using all digital transmission methods specified by the DVB project, such as DVB-S , DVB-T and DVB-C . A set-top box (STB) or a television receiver with the support of the MHP platform is a prerequisite for using MHP offers.

history

MHP is a development by Ulrich Reimers , head of the Institute for Telecommunications at the TU Braunschweig since 1993. In 1991 Reimers initiated the development of the European digital television system together with five colleagues. As part of this, he also created the basis for the DVB project. The MHP standard as such was first published in February 2000.

variants

There are currently three versions of the MHP standard:

  • MHP v1.0 (current version: v1.0.3)
  • MHP v1.1 (current version: v1.1.3)
  • MHP v1.2 (current version: v1.2.2)

(As of March 2010)

The MHP defines two types of application classes based on the two MHP versions:

  • DVB-J: Java applications
  • DVB-HTML: XHTML pages with optionally embedded Java code

These differ essentially in their complexity and the generation of end devices on which they can run.

DVB-J (since MHP 1.0.x)

DVB-J applications are simply programs written in Java. The MHP platform defines a certain number of interfaces ( APIs ) for these programs . This enables the programmer to develop applications that are adapted to the special situation and the limitations of the MHP receiver and require little resources.

DVB-HTML (optional since MHP 1.1.x)

DVB-HTML applications have only been supported since the MHP 1.1 standard. Since the complexity is significantly higher compared to DVB-J, the corresponding functionality is not available in most MHP receivers. Java is also optionally used with DVB-HTML, comparable to the Java applets known from Internet browsers.

technology

Software architecture

Software stack of the MHP platform

The software stack shows the different software layers of an MHP implementation. The two lowest layers, the hardware and the system software (operating system and driver), are separated from the actual MHP interfaces by a Java virtual machine . Since MHP 1.0.3, the Java basis has been the Personal Basis Profile (previous versions used Personal Java), which is based on a CDC -based virtual machine, i.e. the same "virtual machine" that is used by the "big" Java (J2EE / J2SE ) is used.

The special MHP interfaces ( APIs ) allow access to DVB service information, among other things. They contain the EPG , a customized graphical user interface (HAVI UI), access to the data carousel (DSM-CC) in which the MHP applications are transmitted, the management of applications (Xlets) and many other technical aspects of the DVB standards such as such as the MPEG decoder and an optionally available return channel (for interactive applications). Together, these extensions form the MHP API (the programming interface) on which the interoperable MHP applications are executed. The so-called "Navigator" is used to select MHP applications and other DVB services by the user and to control the applications. The navigator is an integral part of the MHP terminal.

implementation

In principle, any manufacturer of set-top boxes or television sets can implement the MHP standard, since the standard is completely open. However, as with almost all DVB standards, the marketing of MHP solutions incurs patent license costs, from 2009 also for the broadcasters (see VIA Licensing - MHP license costs). Due to the complexity of the standard, smaller manufacturers usually use MHP middleware from third-party providers (market leader: Alticast).

A manufacturer may only decorate an MHP receiver with the MHP logo if the receiver has previously passed a test run without any errors. This test, which is carried out by the manufacturers in a self-test, checks the functioning of all elements of the MHP API . The test suite (sum of all tests) is available from the DVB project and is subject to a fee. The current test suite comprises well over 14,000 software tests. This ensures the error-free execution of all applications on the tested MHP implementations. Crashes as well as different behavior of different implementations should be excluded. There is no test suite for testing applications. Carrying out application tests is the sole responsibility of the respective service provider.

Most MHP receivers on the market worldwide (as of July 2005) are based on the MHP 1.0.2 standard.

Application transmission in DVB

The MHP applications are transmitted together with the DVB transport stream, which also contains the digital audio and video data. Within this transport stream, the MHP applications are packaged in DSM-CC (Digital Storage Media Command and Control) object carousels. These carousels are multiplexed (added) cyclically into the DVB transport stream. The cyclical repetition ensures that the application can be received successfully (sooner or later) at every possible switch-on time of the receiver. Of course, applications do not have to be broadcast non-stop; it is entirely possible, for example, to broadcast applications only to accompany a program (e.g. daily news ticker).

The MHP applications are signaled to the MHP receiver via the AIT table (Application Information Table). The content of this SI table (Service Information) enables the recipient to find the DSM-CC carousel with the MHP application and to assign a name as well as a unique ApplicationID and an OrganizationID to the MHP application. The AIT also contains information on the class path (only for DVB-J applications, “J” stands for Java) and the Java-based start class (the “Xlet”).

service

The MHP application can only be operated using the classic remote control. In addition to control using the arrow buttons / OK button, the use of the four color buttons familiar from teletext / teletext enables simple, intuitive operation.

In principle there are two methods of accessing MHP applications. On the one hand, MHP applications are started automatically when a TV channel is selected. In this case, a small message window usually appears in the lower area of ​​the screen. The available application can then be conveniently started by pressing a (mostly red) button. On the other hand, all MHP boxes have a central user interface for selecting applications - the "Navigator" mentioned above. From here, applications can be selected from lists and started.

Return channel

The MHP supports a return channel in order to process orders or payment transactions, for example, via the point-to-point connection that is opened. Currently available MHP systems usually only have an analog modem, if at all. However, the MHP return channel is independent of the transmission technology used. This means that the connection can also be established via ISDN, DSL, cable, GPRS or UMTS, provided the MHP terminal supports this transmission path. The use of a return channel over the digital cable network is of course particularly attractive for cable providers.

distribution

MHP has not been able to establish itself in Germany since its introduction (start of regular operation in October 2002), the proportion of MHP-compatible receivers in DVB boxes was below 0.1% (GfK). In the meantime, devices are no longer available on the German market (as of October 2007, source: receiver search on www.digitalfernsehen.de, availability checked with various price search engines).

An MHP software for the d-box2 developed by Betaresearch for Premiere was withdrawn at the last moment in mid-2003, at the same time, contrary to the Mainz declaration , Premiere postponed the decision to use MHP for two years and in December 2005 opted for the Blucom system from Astra . The introduction of MHP by Premiere (at that time 2 million boxes) would probably have been the breakthrough for MHP.

The current low prevalence in Germany is also due to the lack of availability of the end devices, the lack of support for private television and the limited range of MHP-based applications. Added to this was the dispute over the future standard of interactive television, which has since been settled , and which supplanted other proprietary systems such as OpenTV and led to uncertainty on the part of viewers.

The introduction of MHP in Germany can now be regarded as a failure, so in April 2007 the Hessischer Rundfunk discontinued MHP support for its three programs (including c't-TV). In August 2007, ZDF ended the broadcast of MHP via DVB-T. The public broadcasters have now completely discontinued their offer.

The spread of MHP in Italy and Korea, however, is increasing significantly. According to figures from the DVB project from 2007, around 3.7 million MHP receivers were already in use worldwide, most of them (3.4 million) in Italy and South Korea. This corresponds to a doubling of the worldwide population in around a year.

In Italy, 2.2 million MHP end devices have already been sold through state subsidies for the additional costs incurred by MHP compared to a pure “zapping box”. The reason for these subsidies is, among other things, that the Italian state wants to offer numerous publicly available services to the general public in this way. These subsidies (2004: 120 million euros, 2005: 70 million euros) have been examined by the EU Control Commission, but have not yet been objected to.

In South Korea, 1.2 million satellite MHP receivers had already been sold by July 2005 - without state subsidies, only through grants from the cable operator (the box is cheaper if you take out a cable subscription).

The Belgian cable network provider Telenet now also offers its customers a special MHP terminal through retail outlets. The set-top box can also receive a return channel via an external cable modem that is connected to the set-top box via Ethernet. Future recipients will also have hard drive systems and video-on-demand solutions.

Austria started with the introduction of DVB-T on October 26th, 2006 with MHP services ( ORF OK, ATV OK). The first 100,000 certified MHP boxes sold were to be subsidized in a limited campaign with € 40, but only 35,000 viewers took up this offer. The funding was extended indefinitely, but reduced to € 30. Cable operators met this offer critically or even negatively. ATV discontinued its offer on January 7, 2009. All MHP broadcasting via DVB-T was discontinued on June 30, 2011.

Switzerland wanted to start with MHP in 2007, but has suspended such plans for the time being.

Spain and France have refrained from introducing MHP for DVB-T for the time being because of the new MHP license model.

Provider / TV channels (all discontinued)

ARD
  • TV portal (program overview, personal program creation, additional information)
  • Press club (with return channel)
  • Understand fun (quiz with return channel)
  • Folk music festivals
  • FAKT - The MDR magazine
  • Interactive sports show
  • Rundschau news ticker (Bayerischer Rundfunk)
ZDF
  • ZDFdigitext (the main portal)
  • 1, 2 or 3 (children's quiz)
ORF (Austria)
  • ORF OK MultiText
This offer via DVB-T was discontinued on June 30, 2011.
ATV (Austria)
  • ATV OK MultiText
This offer via DVB-T was discontinued on January 7, 2009.
Others
RTL, Hörzu and Otto Versand stopped their MHP involvement at the end of 2005.

MHP variants and extensions

The MHP is the first of a larger family of standards used worldwide. The first offshoot of the MHP was a variant for the American cable networks, the so-called Open Cable Application Platform (OCAP). OCAP replaces some of the MHP's APIs , which are only required in DVB networks, for example, with replacement solutions. In the course of the development of OCAP, the idea arose to define a DVB standard that describes a common subset of OCAP and MHP and is also suitable for other variants. Such a common subset describes the GEM standard (Globally Executable MHP), which is intended to promote the worldwide dissemination of the MHP. The following standards based on GEM currently exist:

  • MHP, as a software platform in DVB networks,
  • Open Cable Application Platform, as the platform for (American) cable networks,
  • ACAP , a platform for the American terrestrial television networks,
  • ARIB B.23, a variant for the Japanese television networks and
  • BD-J , the variant for the Blu-ray Disc that does not require radio support.

Because all systems are based on GEM, it is possible to develop applications with little effort that can run on all of these systems. Only when special functions, which are only available in individual versions, are to be used, for example for an EPG application, do appropriate adjustments have to be made.

Future developments of the MHP or GEM standard will also be developed in the following areas:

  • the support of the functionality of hard disk recorders (PVR),
  • multimedia home networking,
  • the support of interactive HDTV formats,
  • interactive services via broadband IP connections (e.g. via DSL or the digital cable network) and
  • an abstract, XML-based application description (PCF, Portable Content Format)

Related techniques

In addition to MHP, some cable network operators and device manufacturers use other methods for displaying multimedia content. For example the MicroHTML process, which unlike MHP is not based on DVB standards.

Furthermore, there is a certain relationship to the OSGi standard, which also enables dynamic Java applications, but has no original reference to DVB or digital television - it requires an internet connection for the return channel, as is increasingly found in MHP end devices .

For MIDP , too , work is currently underway on an API for receiving broadcast services. In the future, this would allow interactive services to be received on mobile phones. The two standards could meet again here, as OSGi is now also at home on mobile phones.

More widespread than MHP in Germany are the proprietary middleware OpenTV (at the pay broadcaster BSkyB on a box from Pace) and the MHEG -5, which is favored by the BBC and which also allows the execution of applications.

Relatively new on the market and only related to MHP in the sense that it enables a certain interactivity with a return channel is Blucom (Astra development, requires a Blucom-compatible digital receiver and a Bluetooth-compatible mobile phone for the display and the return channel).

literature

  • Ulrich Reimers: DVB, The Family of International Standards for Digital Video Broadcasting. Second Edition, 2005, ISBN 3-540-43545-X (Chapter 14, MHP)
  • Steven Morris & Antony Smith-Chaigneau: Interactive TV Standards. A Guide to MHP, OCAP, and JavaTV. First Edition, Focal Press, 2005, ISBN 0-240-80666-2 (directed to developers)
  • Edward M. Schwalb: iTV Handbook. Technologies and Standards. First Edition, Prentice Hall, 2004, ISBN 0-13-100312-7
  • Rainer Schäfer: Technical basics of interactive television. In: Christiane zu Salm (ed.): Magic machine interactive television? TV future between blossom dreams and business models. 1st edition, Gabler, 2005 ISBN 3-409-12637-6

Web links

Individual evidence

  1. ↑ Digitalfernsehen.de: Middleware - the failed attempts in Germany from December 30, 2008
  2. ^ Der Standard online: "Cheekiness": UPC against ORF of February 29, 2008