MPEG-21 based Digital Broadcasting Contents
This research mainly related with MPEG-21. Shortly MPEG-21 is multimedia framework for transaction, manipulation and usage, delivery of multimedia contents. With MPEG-21 Standard, anew trend to unify broadcasting and telecommunication environment is arising. MPEG-21 pursuits the framework to build an infrastructure for the delivery and consumption of multimedia contents. So this research deals with Digital interactive TV, Digital Video Broadcasting and so on.
The MPEG-21 Digital Item for Digital Broadcasting Contents should be considered with real broadcasting environment as well as the multimedia framework of MPEG-21 standardization. Mainly this research carries on generation of Digital Item for broadcasting, makes validation check of Digital Item and pursuits integration of MPEG-21 framework with practical broadcasting environment.
The general goal of MPEG-21 activities is to describe an open framework which allows the integration of all components of a delivery chain necessary to generate, use, manipulate, manage, and deliver multimedia content across a wide range of networks and devices.
The MPEG-21 multimedia framework will identify and define the key elements needed to support the multimedia delivery chain, the relationships between and the operations supported by them. Within the parts of MPEG-21, MPEG will elaborate the elements by defining the syntax and semantics of their characteristics, such as interfaces to the elements. MPEG-21 will also address the necessary framework functionality, such as the protocols associated with the interfaces, and mechanisms to provide a repository, composition, conformance, etc. The twelve key elements defined in MPEG-21 are:
¡¤ Part 1 : Technical Report
¡¤ Part 2 : Digital Item Declaration (a uniform and flexible abstraction and interoperable schema for declaring Digital Items)
¡¤ Part 3 : Digital Item Identification and Description (a framework for identification and description of any entity regardless of its nature, type or granularity)
¡¤ Part 4 : Intellectual Property Management Tool Representation and Communication System (the means to enable content to be persistently and reliably managed and protected across a wide range of networks and devices)
¡¤ Part 5 : Right Expression Language
¡¤ Part 6 : Rights Data Dictionary
¡¤ Part 7 : Digital Item Adaptation
¡¤ Part 8 : Reference Software
¡¤ Part 9 : File Format (how the media resources are represented)
¡¤ Part 10 : Digital Item Processing
¡¤ Part 11 : Evaluation of Persistent Association Tools
¡¤ Part 12 : Resource Delivery Test Bed
MPEG-21 recommendations will be determined by interoperability requirements, and their level of detail may vary for each framework element. The actual instantiation and implementation of the framework elements below the abstraction level required to achieve interoperability, will not be specified.
¡á DIGITAL ITEM
A structured digital object, including a standard representation and identification, and meta-data. This entity is the fundamental unit of distribution and transaction within the MPEG-21 framework as a whole.
Figure 1. Exemplary digital item
The MPEG-21 based Digital Broadcasting Item is a configurable, uniquely identified, described by a descriptor language, logical unit for structuring relationships among elements of broadcasted content by referencing to concrete resources of individual broadcast related assets. The end-user perceives it as one entity and as access point to a distributed service pool. DBIs are Dis, which is especially configured for broadcast use.
Figure 2. Exemplary digital item for educational broadcasting
An unambiguous and flexible abstraction and interoperable schema for declaring Digital Items. In this part of ISO/IEC 21000 the standard representation for a Digital Item Declaration is that described by ISO/IEC 21000-2.
The sixteen elements defined in Digital Item Declaration Model.
1. DIDL - A DIDL element is the root element of a DIDL instance document.
2. Declarations - A Declarations element is used to define a set of DIDL elements.
3. Container -A Container is a structure that allows items and/or containers to be grouped.
4. Item -An Item is a grouping of sub-items and/or components that are bound to relevant descriptors.
5. Component -A Component is the binding of a resource to all of its relevant descriptors.
6. Anchor - An Anchor binds descriptors to a fragment, which corresponds to a specific location or range within a resource.
7. Descriptor -A Descriptor associates information with the enclosing element.
8. Condition - A Condition describes the enclosing element as being optional, and links it to the selections that affect its inclusion.
9. Choice - A Choice describes a set of related selections that can affect the configuration of an item.
10. Selection - A Selection describes a specific decision that will affect one or more conditions somewhere within an item.
11. Annotation - An Annotation describes a set of information about another identified element of the model without altering or adding to that element.
12. Assertion - An Assertion defines a full or partially configured state of a choice by asserting true, false or undecided values for some number of predicates associated with the selections for that choice.
13. Resource - A Resource is an individually identifiable asset such as a video or audio clip, an image, or a textual asset. All resources must be locatable via an unambiguous address.
14. Fragment -A Fragment unambiguously designates a specific point or range within a resource. Fragment may be resource type specific.
15. Statement -A Statement is a literal textual value that contains information, but not an asset.
16. Predicate - A Predicate is an unambiguously identifiable declaration that can be true, false or undecided.
The Digital Item Declaration Language described in ISO/IEC 21000-2 is an XML schema based language for representing a Digital Item Declaration. Such a Digital Item Declaration is a static declaration. Digital Item Processing assists processing of a Digital Item Declaration by providing tools allowing a User to add User specified functionality to a Digital Item Declaration. The standardization of Digital Item Processing allows interoperability at the processing level.
¡â DIGITAL ITEM METHOD (DIM)
A key component of Digital Item Processing is the Digital Item Method. A Digital Item Method is the tool whereby a User (author, publisher, distributor, etc.) specifies some desired functionality. As such, Digital Item Methods provide a way for a User to specify a selection of preferred procedures for processing a Digital Item Declaration at the level of the Digital Item itself. For example, a Digital Item representing a music album may contain a Digital Item Method to add a new music track to the album. Such a Digital Item Method can be used to ensure that the new music track is added to the Digital Item while maintaining a preferred format for the Digital Item Declaration of such a music album Digital Item. It is important to note that Digital Item Methods are not intended to be utilized for implementing the processing of media resources themselves. For example, Digital Item Methods are not intended to be used for implementing transcoding of media resources. Digital Item Methods should be viewed from a User perspective; they are intended to be related to User interaction with a Digital Item.
¡â DIGITAL ITEM METHOD LANGUAGE (DIML)
A Digital Item Method is expressed using the Digital Item Method Language which includes a binding for Digital Item Base Operations. The Digital Item Method Language provides the basic syntax, control flow constructs, etc for authoring a Digital Item Method.
¡â DIGITAL ITEM BASE OPERATION (DIBO)
The Digital Item Base Operations are the functional building blocks utilized by a Digital Item Method. They can be considered somewhat analogous to the standard library of functions of a programming language. Digital Item Methods are defined by the Digital Item Base Operations they use to accomplish the handling of the Digital Item according to the intentions of the Digital Item Method author.
¡â DIGITAL ITEM EXTENSION OPERATION (DIxO)
An operation allowing extended complex functionality to be invoked from a Digital Item Method.
¡â DIGITAL ITEM METHOD ENGINE (DIME)
The component of a Digital Item Processing Engine responsible for interpreting and executing a Digital Item Method and managing the Digital Item Method Object Map.
Figure 3 shows how Digital Item Processing (DIP) fits into the ISO/IEC 21000 terminal. The Digital Item Method Engine (DIME) can be seen as a central point in the terminal architecture. In order to provide functionality specified in the Digital Item Methods the DIME will need to be able to communicate with the other parts of the terminal.
Figure 3. An overview of DIP
The left dashed-line arrow depicts interaction between the ISO/IEC 21000 terminal and a Digital Item that arrived at this terminal. The right dashed-line arrow depicts interaction between a User and his/her ISO/IEC 21000 terminal. The full-line arrows depict interaction inside the ISO/IEC 21000 terminal. Digital Items are intended to be used throughout the delivery chain, and thus different applications and different Users will perform different overall processing of a Digital Item. It is thus important that Digital Item Methods are regarded as a ¡®menu¡¯ of User interaction possibilities.