- Globally Executable MHP
Globally Executable MHP (GEM) is a "subset" specification of
Multimedia Home Platform (MHP) forDVB , also known as ITU "Recommendation ITU-T J.202". GEM is not intended to be directly implemented, but rather forms the basis for broader specifications targeting a particular network infrastructure (i.e. US cable) or class of device (i.e.Blu-ray Disc players).History
A few years ago, the
DVB project started the development of a Java-based application platform (a set of APIs), called MHP, intended to support software applications running on digital television platforms. Such applications could includeElectronic Program Guide s (EPG's), interactivity,Video on Demand (VOD), email through your television, etc. The MHP specification defines the download of MHP applications ("xlets ") over transmission networks based on other DVB specifications (i.e. over-the-air or terrestrial networks usingDVB-T , satellite networks usingDVB-S , cable networks usingDVB-C ). As other specification bodies such asCableLabs and theBlu-ray Disc Association chose to base their own DTV software standards on MHP it became necessary to define a subset of MHP which removes the transmission-related elements of the MHP specification but retains the applicationAPI 's, thus allowing broad content compatibility across a range of delivery platforms.Platforms
At the time of writing, the following platforms are defined, which base on/extend GEM:
* theMultimedia Home Platform (MHP), the open, multi-platform middleware specification developed by the DVB project,
* theOpenCable Application Platform (OCAP), which is anInteractive television (iTV) middleware software layer for US cable,
* theAdvanced Common Application Platform (ACAP) from North America’sATSC ,
* the ARIB B.23 specification from Japan'sARIB ,
*BD-J the Java-platform for theBlu-ray disc
*GINGA-J specification from Brazil's GINGA.As all these platforms are based on the common GEM-core, it is possible to write Java applications that will run interoperably on all these systems.
External links
* [http://www.mhp.org Official GEM and MHP website - redesigned May 2008]
* [http://www.dvb.org Digital Video Broadcasting]
* [http://www.itvdictionary.com/g.html The Online ITV Dictionary]
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