Search

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.

International audience; MPEG-7 has emerged as the standard for multimedia data content description for efficiently describing multimedia content. In this context, its primary goal is to provide flexible and effective searching and retrieval of multimedia resources. Most of the earlier work on MPEG-7 description schemes (DSs) and descriptors (Ds) focuses on the description of a single multimedia document, whereas MPEG-7 can be further exploited to support more advances implementations under multimedia database systems. Therefore, it is important to reconsider issues related to high level multimedia modeling and representation, in the light of the MPEG-7 perspective. In this paper, we propose a high level multimedia representation and description scheme based on multi-level video modeling and semantic video classification. The proposed multi-level multimedia representation and DSs are expected to support more effective video content indexing and accessing operations. The presented DSs and Ds are further described by using the XML Schema language, which has been adopted as the basis of the Description Definition Language (DDL) of the MPEG-7 standard.

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.

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 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.