Preface

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Imagine, you download an MP3 (Moving Picture Experts Group [MPEG] 1 Audio layer 3) file, recorded in the U.S., sung by a French singer, stored in a server in Japan, routed over the Internet through Asia and Europe, and listened to on the top of an Austrian hill on a mobile phone produced in Germany.

Isn't this astonishing that all this works? How is this possible?

The main craft behind this cooperative international success is the standardization work of different organizations (International Organization for Standardization [ISO], International Electronic Commission [IEC] and their Moving Picture Experts Group [MPEG], International Telecommunications Union [ITU], and others) that makes this possible. Their definitions of interoperable multimedia formats and their specifications of decoder architectures make it possible that the same multimedia file may be consumed everywhere and anytime. From these core technologies, new and emerging standards will help us to access multimedia by their content; for example, to show all images where a dog runs after a ball, or all videos where Greta Garbo is laughing. At the same time, we can set up a multimedia framework that enables the transparent and augmented use of multimedia resources across heterogeneous networks and terminals; for example, we may define the rights a user may exercise on our digital photo album.

Today's multimedia systems are complex self-organizing file-sharing systems (see, e.g., the popular Morpheus system). The main components of such systems are database, multimedia storage server, network, and client systems in a more and more mobile environment. However, this is not enough. New standards tie these components together. These are the new and emerging standards by the ISO/IEC JTC 1/SC 29/WG 11 MPEG, namely, the MPEG-4, MPEG-7, and MPEG-21 standards. They offer standardized technology for coding multimedia data, natural and synthetic (e.g., photography and face animation, respectively) and continuous and static (e.g., video and image, respectively), as well as for describing content (Multimedia Description Interface) and for an open multimedia framework for a fair and interoperable use of multimedia in a distributed environment. We will also point out the relationship to some of the popular multimedia formats, MP3 and MP4, which are based on the MPEG coding family.

In addition to coding and describing multiple kinds of information, it is imperative to integrate their semantic meaning into the main actors of a system adequately (and not only in the database but also in network elements, users, etc.). For example, a multimedia newspaper will include text, images, audio, and short clips. An automatic analysis tool filtering out the news, which meets the user's interest, may consume it. The presented multimedia objects are conceptually related and have to exist in conjunction with each other. Synthesizing and synchronizing the various forms of information provided by the multiple media based on user needs are very important parts of the multimedia application.

The new object-coding standard, MPEG-4, will help us to integrate these diverse media in one format, in one stream, in one description, and in one architecture. In addition, and equally important, is MPEG-7 (an international standard since 2002), which provides us with a structured metadata description for semantically rich media content. It will help us to search, select, and finally access the desired information in the immensely growing forest of available multimedia content information. The currently established MPEG-21 standard introduces an open multimedia framework for a fair and interoperable use of multimedia in a distributed environment. In this sense, it incorporates resources (e.g., MPEG-4, but not exclusively) and their description (using MPEG-7 or other multimedia description standards).

Multimedia database management systems (MMDBMSs) are the technology for content management, storage, and streaming. Furthermore, a MMDBMS must be able to handle diverse kinds of data and to store sufficient information to integrate the media stored within. In addition, to be useful, a database has to provide sophisticated mechanisms for querying, processing, retrieving, inserting, deleting, and updating data. Structured query language (SQL)/MM, the multimedia extension to SQL developed by the SC 39 of ISO/IEC, supports multimedia database storage and content-based search in a standardized way.

A multimedia system needs a mechanism to communicate with its environment, with the Internet, with the clients, and with the applications in general. MPEG-7 provides a standard multimedia metadata format for global communication, but it does not provide the framework to let the different active and passive players in a global multimedia system interact. MPEG-21 closes this gap by establishing an infrastructure for a distributed multimedia framework. Digital items are created and consumed, and users can interact with, modify, view, and communicate them. A digital item is a container for all multimedia data and content and is an interoperable unit in a distributed multimedia system, which may be handled by all players participating in the MPEG-21 agreement.

In this sense, this book describes the technologies, concepts, and tools of distributed, content-based multimedia systems. We focus on the practical uses of the standard technologies of MPEG and SQL/MM in these components and for interoperability among them (for data exchange, transactions, interaction, etc.). This book presents a vision of an open distributed multimedia framework that encompasses a single view of components in such a way that it lets these components integrate in a cooperatively working environment, which offers rich multimedia access in an increasingly mobile world.

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