1). ESG - Data Model
§ ESG consists of two essential types of information: user attraction information and acquisition information.
§ User attraction information describes services and their contents while the acquisition information contains information for service acquisition.
§ In the DVB-H system, ESG plays major role in service discovery, in addition to PSI/SI.
§ The ESG data model is defined based on XML Schema and it is aimed at being consistent across all implementations of a system to ensure interoperability.
§ To define a set of data structures, which can be instantiated to describe available services.
§ The ESG subdivides into ESG Fragments, which can be instantiated as parts of the ESG.
2). ESG Instance of the ESG Data Model
§ Instantiation: Described by the ESG Instance based on the data model using XML Schema.
§ is a consistent set of ESG data describing the available IP Datacast services.
§ ESG XML Fragment: ESG Fragment of an XML instance which is an instantiation of a datatype
3). The semantics of the represented following fragments: (first layer - data model)
§ Figure below depicts the ESG Fragments and the relations between them.
§ To provide all this information in well-formed, consistent and interoperable manner, the ESG specification presents the data model, which describes the structure of the ESG.
§ The model is defined based on XML Schema and the contents are divided in seven fragments in order to manage and deliver them independently.
§ The Purchase, PurchaseChannel, and ServiceBundle Fragments provide information about service groups and how to purchase them.
4). ESG Fragment Overview:
1. Purchase Fragment: Purchase information of a service (bundle).
§ The purchase fragment is an entity which provides information necessary to gain access to a particular set of services.
§ This information is composed of both attractor information and data required by the referenced SPP system to enable the purchase of rights to consume the set of services.
2. PurchaseChannel Fragment: Interface allowing the user to purchase content.
§ The purchase channel fragment provides information about a service provider offering service bundles for purchase.
§ This information includes a description of the provider and its contact points (e.g. telephone number, URL) that can be displayed to the user, or used by the terminal for an automatic purchase.
§ Additional information that is specific to the key management system used by the provider can also be included in this fragment.
3. ServiceBundle Fragment: Groups a set of services together to present them as a single entity to the user (typically a set of services that can be accessed through a unique purchase).
§ The service bundle fragment is used to group one or more services. The service bundle fragment can then be referenced by a purchase fragment enabling the purchase of rights to the set of services forming the service bundle.
§ This is an optional fragment type, however at least one service bundle fragment must be present if a purchase fragment is available.
4. Service Fragment: An IPDC service (for example, a channel).
§ The Service Fragment describes the basic features of the service. Where a service offering may be for example:
- a streaming service;
- a download service;
- a combination of streaming and download.
§ The service fragment provides descriptive and possibly visual information which may be used to attract a user to consume the service, and control information to enable a terminal to configure itself for consumption of the service
5. Acquisition Fragment: Information necessary to access a service or content.
§ The Acquisition Fragment provides information needed for the service acquisition and launching it, like SDP data for video streams etc.
§ The acquisition fragment provides information required for the consumption of the content referenced by a service or schedule event fragment.
§ Specifically the acquisition fragment contains the SDP or the location of an SDP stream which carries the SDP.
§ For services containing streamed media such as TV services it is recommended that at least one default acquisition fragment is referenced by a service fragment, with additional optional acquisition fragments being referenced from schedule event fragments, to signal additional options to those signalled within the services default acquisition.
§ The default acquisition fragment is assumed to describe the continuously available set of media components that form the service.
6. Content Fragment: Metadata describing specific content that is part of a service (a TV show, for example). It may be instantiated several times.
§ The Content Fragment specifies more detailed information about the contents of the service.
§ The content fragment provides metadata about a content item. This content item may be a video and/or audio asset, or an interactive application.
§ A content item is the smallest entity in the understanding of a non technical person e.g. a video composed from audio and video or an interactive application.
§ The metadata is used to provide information to the user about the content of a schedule event respectively of a service.
§ There is one content fragment for every content item.
7. ScheduleEvent Fragment: Defines the broadcast time of an instance of content.
§ The ScheduleEvent Fragment specifies time-dependant contents in the service and acquisition reference when these particular contents are available.
§ The schedule event fragment defines a period of time during which one content item is transmitted on the referenced streaming service.
§ It can also define a period of time during which one or more content items are transmitted on the referenced file download service.
§ In both cases the time period is described by the elements PublishedStartTime and PublishedEndTime.
§ Although the instantiation of PublishedStartTime is optional, it is recommended to use it.
5). ESG Fragment in Data Model
ESG Main Element Semantics: (N/A Here)
ESG Semantics: (N/A Here)
ESG XML Fragment Reference Semantics: (N/A Here)
Related Material Semantics: (N/A Here)
ProviderType Semantics: (N/A Here)
Service Fragment Semantics: (N/A Here)
Service Bundle Fragment Semantics: (N/A Here)
Content Fragment Semantics: (N/A Here)
Schedule Event Fragment Semantics: (N/A Here)
Purchase Fragment Semantics: (N/A Here)
Purchase Channel Fragment Semantics: (N/A Here)
Acquisition Fragment Semantics: (N/A Here)
Session Description Semantics: (N/A Here)
Zapping Support Semantics: (N/A Here)
Key Stream Semantics: (N/A Here)
ComponentCharacteristic: (N/A Here)
AudioComponentCharacteristic: (N/A Here)
VideoComponentCharacteristic: (N/A Here)
FileDownloadComponentCharacteristic: (N/A Here)