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The MPEG-7 standard is a step towards standardizing the description of multimedia content so that quick and efficient identification of relevant content can be facilitated, together with efficient management of information. The description definition language (DDL) is a schema language to represent valid MPEG-7 descriptors and description schemes. MPEG-7 instances are XML documents that conform to a particular MPEG-7 schema, as expressed in the DDL and that describe audiovisual content. In this paper, we pick one of the visual descriptors related to motion in a video sequence, viz., motion trajectory. It describes the displacements of objects in time, where an object is defined as a spatiotemporal region or set of spatiotemporal regions. We present a method of automatically extracting trajectories from video sequences and generating an XML document that conforms to the MPEG-7 schema. We use sports videos in particular, because the trajectories are very random and the robustness of our algorithm can be demonstrated. The MPEG-7 XM software is a working tool that enables the checking of the relative performance of various algorithms. Insofar as the motion trajectory is concerned, the current version of XM(version 5.5) takes the formatted key-point list of the already segmented object as inputs and outputs the trajectory as an XML document. However, we go a step further by developing an automatic trajectory extraction algorithm that produces motion blobs, which are then tracked to generate the trajectory, which in turn is output as an XML document.

The description of an audiovisual document represents a major challenge for multimedia retrieval. Indeed, the lack of descriptive metadata extraction makes these proliferated resources underused in the querying process. To overcome these difficulties, the extraction of the semantic metadata of the content and the different structures of an audiovisual document is required. In this paper, we present a method that enables an automatic description of audiovisual documents. This automatic process is mainly based on the use of a multitude of modalities for the description and modeling of audiovisual documents, the standardization of these descriptions in the MPEG-7 standard through its description definition language (DDL) and on the use of semantic web language to link between the audiovisual resources.

MPEG-7 multimedia description schemes (MDSs) are metadata structures for describing and annotating audio-visual (AV) content. The description schemes (DSs) provide a standardized way of describing in XML the important concepts related to AV content description and content management in order to facilitate searching, indexing, filtering, and access. The DSs are defined using the MPEG-7 description definition language, which is based on the XML Schema language, and are instantiated as documents or streams. The resulting descriptions can be expressed in a textual form (i.e., human readable XML for editing, searching, filtering) or compressed binary form (i.e., for storage or transmission). In this paper, we provide an overview of the MPEG-7 MDSs and describe their targeted functionality and use in multimedia applications.

This paper presents an overview of the MPEG-7 description definition language (DDL). The DDL provides the syntactic rules for creating, combining, extending and refining MPEG-7 descriptors (Ds) and description schemes (DSs). In the interests of interoperability, the W3C's XML Schema language, with the addition of certain MPEG-7-specific extensions, has been chosen as the DDL. This paper describes the background to this decision and using examples, provides an overview of the core XML Schema features used within MPEG-7 and the extensions made in order to satisfy the MPEG-7 DDL requirements.

This paper describes the DDL proposals submitted in response to the MPEG-7 Call for Proposals and the results of their evaluation at the MPEG-7 AHG Test and Evaluation Meeting in Lancaster in February 1999. It also describes the proposal from DSTC which was considered to provide the best starting point for a DDL and the features from other proposals which were considered to be of value for future consideration and possible integration. It concludes with an overview of the current state of the MPEG-7 DDL work.

To enable the resource discovery of audiovisual documents over the World Wide Web, it will be necessary to define content description standards or metadata standards for complex, multi-layered, time-dependent information-rich audiovisual data streams. In particular, this is the primary goal of the emerging MPEG-7 standard, the ``Multimedia Content Description Interface'' under development by the MPEG group. In the past, a lot of effort has gone into generating descriptors and description schemes for video indexing but comparatively little research has been done on schemas capable of defining the structure, content and semantics of video documents and enabling validation and higher levels of automated content checking. This paper compares the capabilities of the RDF Schema, Extensible Markup Language (XML), Document-type Definitions (DTDs), Document Content Description (DCD), and Schema for Object-Oriented XML (SOX), for supporting and validating hierarchical video descriptions based on Dublin Core, MPEG-7 and a specific hierarchical structure. Finally, this paper proposes a hybrid schema based on features from each of these schemas which will satisfy the MPEG-7 Description Definition Language (DDL) requirements.

MPEG-7 (Multimedia Content Description Interface) is a standard for describing the content of multimedia data and adopts XML (eXtensible Markup Language) Schema as its Description Definition Language. However, as a forthcoming standard for querying XML data/documents, XQuery (XML Query Language) has weakness in the query of vector-based feature described in MPEG-7. Thus, we propose an extension to XQuery, that is, VeXQuery (Vector-based XQuery) language, to resolve the problem of vector-based feature query in MPEG-7 retrieval. To fulfill the vector-based feature query, VeXQuery gives a set of vector similarity measurement expressions and defines the formal semantics of VeXQuery in terms of XQuery itself. Through this approach VeXQuery can be integrated seamlessly into XQuery.

As the number of installed surveillance cameras increases, and the cost of storing the compressed digital multimedia decreases, the CCTV industry is facing the prospect of large multimedia archives where it may be very difficult to locate specific content. To be able to get the full benefit of this wealth of multimedia data, we need to be able to automatically highlight events of interest to the operator in real-time. We also need to make it possible to quickly identify and retrieve content which meets particular criteria. We show how advances in the Internet and multimedia systems can be used to effectively analyze, tag, store, search and retrieve multimedia content in surveillance systems. IP cameras are utilized for multimedia compression and delivery over the Internet or intranet. The recorded multimedia is analyzed in real-time, and metadata descriptors are automatically generated to describe the multimedia content. The emerging ISO MPEG-7 standard is used to define application-specific multimedia descriptors and description schemes, and to enforce a standard Description Definition Language (DDL) for multimedia management. Finally, a graphical multimedia retrieval application is used to provide content-based searching, browsing, retrieval and playback over the Internet or intranet.

MPEG-7 provides a set of tools for the definition of a standard description for multimedia information. It uses XML Schema as its own Description Definition Language (DDL) to provide an ability to extend standard description to user application domains. However, due to its lack of expressive power, XML Schema cannot represent the implicit information of multimedia contents and hence cannot yield derived descriptions. In order to enhance the expressive power of multimedia annotations--described in terms of an XML document--and to maintain the advantages of XML Schema, there appears to be a need of a new schema language which can handle those abilities. XML Declarative Description (XDD) is a representation framework which can encode any XML document and application (e.g., XML Schema, RDF, RDF Schema, and DAML+OIL). It enhances XML expressive power by employing Declarative Description (DD) theory and also provides a mechanism for reasoning about new information from existing data. Moreover, it can specify constraints as well as ontological axioms. Thus, it is employed to construct a schema language for MPEG-7.

In this paper, we describe a multimedia annotation tool that allows the users to interactively create MPEG-7 descriptions. The MPEG-7 standard provides description structures for multimedia content in the form of Description Schemes (DS) and Descriptors with the goal of enabling interoperable searching and filtering. The MPEG-7 Visual Annotation Tool allows the user to manually link together MPEG-7 Dss and Descriptors as needed and enter description data into the fields of the description structures. The tool takes as input an MPEG-7 Schema definition file and an MPEG-7 package description file. The MPEG-7 Schema definition file defines the structure of the MPEG-7 description components using the MPEG-7 Description Definition Language (DDL). The Package description file organized the MPEG-7 description components in order to improve the ease of navigation in the MPEG-7 Visual Annotation Tool. The tool provides utilities for drag-and-drop copying and reusing of description elements and allows the output of the descriptions in XML to files. The initial implementation centers around manual entry of description data, however, in future work we plan to explore the integration of automatic and semi-automatic feature extraction methods with the goal of providing a complete system for MPEG-7 multimedia content annotation and query instruction.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The ongoing MPEG-7 standardization activity aims at creating a standard for describing multimedia content in order to facilitate the interpretation of the associated information content. Attempting to address a broad range of applications, MPEG-7 has defined a flexible framework consisting of Descriptors, Description Schemes, and Description Definition Language. Descriptors and Description Schemes describe features, structure and semantics of multimedia objects. They are written in the Description Definition Language (DDL). In the most recent revision, DDL applies XML (Extensible Markup Language) Schema with MPEG-7 extensions. DDL has constructs that support inclusion, inheritance, reference, enumeration, choice, sequence, and abstract type of Description Schemes and Descriptors. In order to enable multimedia systems to use MPEG-7, a number of important problems in storing, retrieving and searching MPEG-7 documents need to be solved. This paper reports on initial finding on issues and solutions of storing and accessing MPEG-7 documents. In particular, we discuss the benefits of using a virtual document management framework based on XML Access Server (XAS) in order to bridge the MPEG-7 multimedia applications and database systems. The need arises partly because MPEG-7 descriptions need customized storage schema, indexing and search engines. We also discuss issues arising in managing dependence and cross-description scheme search.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.