scope:

The present document defines the GEM platform. GEM is applicable for specifications and standards based on the GEM APIs, content formats, and semantic guarantees.

The present document is firstly intended to be used by entities writing terminal specifications and/or standards based on GEM. Secondly it is intended for developers of applications that use the GEM functionality and APIs. The GEM specification aims to ensure interoperability between GEM applications and different implementations of platforms supporting GEM applications. This includes interoperability across different middleware specifications, e.g. MHP [1], Blu-ray [13], OCAP [5], ACAP [7], ARIB [6], and the Open IPTV Procedural Application Gateway [8]. Implementers should consult the publisher of specifications which reference GEM regarding conformance.

NOTE: The present document defines the interfaces visible to applications. Application developers should not assume that any related interface is available unless it is specifically listed. Terminal standards or implementations may have other interfaces present.

Since the current business models for delivery of DVB services via broadband IP networks are more operator controlled than was assumed for the original GEM, the present document extends GEM with support for operator supplied applications which run all the time that the GEM environment is running. There is also the possibility that where an operator has subsidised the GEM terminal, applications from that operator may have specially privileges not available to normal applications.

Clauses 1 to 14 specify the applicable technologies and technical definitions in a generic way. Clause 15 provides detailed profile definitions for the following initial profiles:

• Enhanced Broadcasting;

• Interactive Broadcasting;

• Enhanced Packaged Media;

• Interactive Packaged Media;

• IPTV;

• OTT,

which can be extended with future additional profile definitions.

Clause 16 provides a registry of constants and clause 17 describes requirements for internet access clients.

One of the primary goals of the present document is to minimize the number of divergences between GEM and MHP terminal specifications, wherever practical. Divergence is defined in clause 3.1. Where divergences are inescapable, the present document serves as a place to document and control the permitted divergences, so that they will be predictable to terminal manufacturers, broadcasters, and application authors.