INTERNATIONAL ORGANISATION FOR STANDARDISATION
ORGANISATION INTERNATIONALE DE NORMALISATION
ISO/IEC JTC1/SC29/WG11
CODING OF MOVING PICTURES AND AUDIO
ISO/IEC JTC1/SC29/WG11
MPEG2001/N4251
Sydney, NSW - 16 – 20 July 2001
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Title: |
MPEG-2 – Frequently Asked Questions (FAQs) ver 1.0 |
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Source: |
MDS |
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Authors: |
Paul Ruskin |
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Status: |
Approved |
Content
GeneralDigital Item Declaration Digital Item Identification and Description Content Handling and Usage Intellectual Property Management and Protection Terminals and Networks Content Representation Event Reporting Standardisation Questions
- 3. What is MPEG-21 and why does it exist?
- 4. What is a Digital Item?
- 5. What areas are covered by MPEG-21?
- 6. What applications are suitable for using MPEG-21?
- 7. How does MPEG-21 relate to the other MPEG standards?
- 8. Why isn’t this work being done as part of MPEG-7?
- 9. Can I use MPEG-7 Description Schemes with MPEG-21?
- 10. Is MPEG developing this standard in isolation?
This document provides answers to Frequently Asked Questions (FAQs) related to MPEG-21. It is subject to continuous update and improvements. Any comments or suggestions should be forwarded to the MPEG-21 reflector (mpeg-21-list@imec.be) or directly to one of the FAQ editors: (i.e., pruskin@ieee.org)
The following questions and answers were developed by the Multimedia Description Scheme (MDS) Group during MPEG’s 57th meeting in Sydney in July, 2001.
Today, many elements exist to build an infrastructure for the delivery and consumption of multimedia content. There is, however, no 'big picture' to describe how these elements, either in existence or under development, relate to each other.
The vision for MPEG-21 is to define a multimedia framework that will enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities. The intent is that the framework will cover the entire multimedia content delivery chain encompassing content creation, production, delivery and trade.
The framework will describe how these existing components can be used together. Where gaps exist new standards will be developed by MPEG to satisfy the requirements.
The basic architectural concept in MPEG-21 is the Digital Item.
Digital Items are structured digital objects, including a standard representation and identification, and metadata. They are the basic unit of transaction in the MPEG-21 framework.
Basically, a Digital Item is a combination of resources (such as videos, audio tracks, images, etc), metadata (such as MPEG-7 descriptors), and structure (describing the relationship between resources).
MPEG has identified key areas to be addressed in order to provide an interoperable multimedia framework. These areas are:
1. Digital Item Declaration (a uniform and flexible abstraction and interoperable schema for declaring Digital Items);
2. Digital Item Identification and Description (a framework for identification and description of any entity regardless of its nature, type or granularity);
3. Content Handling and Usage (provide interfaces and protocols that enable creation, manipulation, search, access, storage, delivery, and (re)use of content across the content distribution and consumption value chain);
4. Intellectual Property Management and Protection (the means to enable intellectual property rights on content to be persistently and reliably managed and protected across a wide range of networks and devices);
5. Terminals and Networks (the ability to provide interoperable and transparent access to content across networks and terminals);
6. Content Representation (how the media resources are represented);
7. Event Reporting (the metrics and interfaces that enable Users to understand precisely the performance of all reportable events within the framework);
MPEG-21 is suitable for many types of applications. Some of the use cases that the standard has been developed to satisfy include:
• Digital Libraries
• Broadcast usage
• Publishing
• Music/Video Releases
• Asset management
• Cataloguing in publication
• Trade transactions
The MPEG standards cover different areas. Broadly speaking, they can be broken into:
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MPEG Standard |
Targeted Usage |
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MPEG-1 MPEG-2 MPEG-4 |
Coding of audio/visual content |
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MPEG-7 |
Providing metadata that describes multimedia content |
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MPEG-21 |
Providing a framework for the all-electronic creation, production, delivery and trade of content. Within the framework we can use the other MPEG standards where appropriate. |
MPEG-7 deals mainly with providing descriptions of multimedia content. MPEG-21 is much broader and aims to deals with composite units that consist of multiple resources, how the resources are interrelated as well as the methods by which content can be distributed.
Yes. The DID allows the inclusion of metadata expressed in any format.
No. MPEG is liasing and collaborating with other standards bodies to expedite the development of this standard and ensure its interoperability with other technologies.
Digital Items are declared using the Digital Item Declaration Language (DIDL). Declaring a Digital Item involves specifying its resources, metadata and their interrelationships.
The DIDL is a language based on an XML schema that has developed to allow the declaration of Digital Items within MPEG-21. It is a flexible and general schema that provides the hooks for higher level functionality.
Several use cases exist for ways in which this can occur. These include:
• Distribution across a network: the Digital Item Declaration is distributed and contains references to places on the network from which the resources can be retrieved.
• Distribution as a stand-alone object: the Digital Item Declaration is distributed with its resources.
No. The Digital Item Declaration may contain references that indicate where the resources are located. This means that it is only necessary to distribute the Digital Item Declaration to a user. The user may then retrieve the resources the Declaration describes as required.
Currently, the majority of content lacks identification and description. Additionally, there is no mechanism to ensure that this identity and description information is persistently associated with the content, which hinders any kind of efficient content usage. MPEG-21 aims to provide the tools necessary to overcome these issues.
The Digital Item Declaration allows the inclusion of metadata to describe the item and its resources. Descriptors defined using DIID can be included in the Digital Item in this manner.
MPEG will ensure that standards exist to facilitate searching, locating, caching, archiving, routing, distributing and using content (which can be any media data and/or descriptive data).
MPEG is currently developing a multimedia digital rights management framework that will enable all Users to express their rights to, interests in, and agreements related to Digital Items. It will also enable all Users to derive appropriate levels of assurance that those rights, interests and agreements will be persistently and reliably managed and protected across a wide range of networks and devices.
MPEG-21 will address the issues associated with the provision of content transparently adapted to meet terminal and network requirements (including quality of service).
Content representation is an important part of any multimedia framework. MPEG will ensure that there are content representations available that are suitable to achieve the objectives of MPEG-21.
Every interaction is an event. Arising from this event, there is the opportunity to describe what occurred. MPEG-21 aims to provide the tools to describe and report events as they occur through the MPEG-21 framework.
• AHG - Ad Hoc Group
• CE - Core Experiment
• DIDEF – Digital Item Description Framework
• DIDL – Digital Item Declaration Language
• DIID – Digital Item Identification and Description
• MPEG - Moving Picture Experts Group
• MPEG-21 - MPEG standard "framework for multimedia interoperability"
• PDTR – Proposed Draft Technical Report
• WD - Working Draft
• XML - Extensible Markup Language
• YM – Systems and Software Model
The following table sets out the current timetable for MPEG-21standardisation:
|
Part |
Title |
CfP |
WD |
CD PDAM PDTR |
FCD FPDAM |
FDIS FDAM DTR DCOR |
IS AMD TR COR |
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1 |
Vision, Technologies and Strategy |
01/01 |
01/07 |
01/09 |
|||
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2 |
Digital Item Declaration |
01/01 |
01/07 |
01/07 |
02/03 |
02/05 |
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|
3 |
Digital Item Identification and Description |
01/01* |
01/03* |
01/07* |
01/07* |
02/03* |
02/05* |
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4 |
Rights Data Dictionary and Rights Expression Language |
01/07* |
01/10* |
01/12* |
02/03* |
02/07* |
02/09* |
If you are a member of MPEG, you may participating in the meetings on the areas of MPEG-21 which are held at the MPEG meetings. You may also by join one of the Ad Hoc Groups, subscribe to various reflectors, and participate in Core Experiments (CEs) depending on your interest.
If you have any further questions, you may send email to the reflector at mpeg-21-list@imec.be.
There are a number of documents available at the MPEG Home Page at http://mpeg.cselt.it/, including:
• MPEG-21 Proposed Draft Technical Report
• Study of the Proposed Draft Technical Reports
• MPEG-21 Use Case Scenarios
• Digital Item Declaration Language
• Requirements for a Rights Data Dictionary and Rights Description Language
If you are not yet a member of MPEG, please find information about joining at http://mpeg.cselt.it/how_to_join.htm.