Abstract: This paper presents a cross-layer model—formulated using interoperable description formats—for the adaptation of scalable H.264/MPEG-4 AVC (i.e., SVC) content in a video streaming system operating on aWireless LANaccess network without QoS mechanisms.SVCcontent adaptation on the server takes place on the application layer using an adaptation process compliant with the MPEG-21 Digital Item Adaptation (DIA) standard, based on input comprised of MPEG-21 DIA descriptions of content and usage environment parameters. The latter descriptions integrate information from different layers, e.g., device characteristics and packet loss rate, in an attempt to increase the interoperability of this cross-layer model, thus making it applicable to other models. For the sake of deriving model parameters, performance measurements from two wireless access point models were taken in account. Throughout the investigation it emerged that the behavior of the system strongly depends on the access point. Therefore, we investigated the use of end-to-end-based rate control algorithms for steering the content adaptation. Simulations of rate adaptation algorithms were subsequently performed, leading to the conclusion that a TFRC-based adaptation technique (TCP-Friendly Rate Control) performs quite well in adapting to limited bandwidth and varying network conditions. In the paper we demonstrate howTFRC-based content adaptation can be realized using MPEG-21 tools.

Abstract: While there is a lot of hype around various concepts associated with the term Web 2.0 in industry, little academic research has so far been conducted on the implications of this new approach for the domain of education. Much of what goes by the name of Web 2.0 can, in fact, be regarded as new kinds of learning technologies, and can be utilised as such. This paper explains the background of Web 2.0, investigates the implications for knowledge transfer in general, and then discusses its particular use in eLearning contexts with the help of short scenarios. The main challenge in the future will be to maintain essential Web 2.0 attributes, such as trust, openness, voluntariness and self-organisation, when applying Web 2.0 tools in institutional contexts.

Abstract: Content adaptation is an important issue of multimedia frameworks in order to achieve universal multimedia access (UMA), i.e., to enable consumption of multimedia content independently of the given resource limitations, terminal capabilities, and user preferences. The digital item adaptation (DIA) standard, one of the core specifications of the MPEG-21 framework, supports content adaptation considering a wide range of networks, devices, and user preferences. Most adaptive multimedia frameworks targeting the UMA vision do not consider utility aspects in their adaptation decisions. This paper focuses on a generic semantic-based audio–visual utility model for DIA that aims to enhance the multimedia experience for the user. Our proposed model is able to take the semantics and the perceptual features of the content as well as the users' specific utility aspects into account. Based on a detailed analysis of these constraints, we will show how the model reacts on individual input data. For choosing the best adaptation decision considering resource limitations on client and server sides as well as network characteristics, we evaluate four algorithms for performing this adaptation decision taking task. We will discuss results according to some use case scenarios.

Abstract: Is Web 2.0 just hype or just a buzzword, which might disappear in the near future One way to find answers to these questions is to investigate the actual benefit of the Web 2.0 for real use cases. Within this contribution we study a very special aspect of the Web 2.0 the folksonomy and its use within self-directed learning. Guided by conceptual principles of emergent computing we point out methods, which might be able to let semantics emerge from folksonomies and discuss the effect of the results in self-directed learning.

Abstract: Intelligent, server-side adaptation of multimedia resources is becoming increasingly important and challenging for two reasons. First, the market continuously brings up new mobile end-user devices to which the content has to be adapted as these devices support different display formats and operate on various types of networks. On the other hand, with the help of metadata annotations which are now available in the MPEG-7 and MPEG-21 standard, advanced forms of resource adaptations on the content level become possible. As none of the existing multimedia transformation tools and libraries can support all these different forms of basic and advanced adaptation operations, an intelligent multimedia adaptation server has to integrate such external tools and algorithms and perform an adequate sequence of adaptation operations on the original resource before sending it to the client. In this paper we present the results of the ISO/IEC MPEG core experiment on using Semantic Web Services technology as a tool for declaratively describing the semantics of adaptation services and constructing multi-step adaptation sequences in an open and extensible multimedia adaptation framework. We show how the semantics of adaptation operations can be captured in the form of input, output, precondition, and effects, how the problem of finding adequate adaptation sequences can be viewed as an Artificial Intelligence planning problem, and finally, how the existing MPEG standards are technically integrated into the service descriptions and how they serve as the shared ontology of the domain. Our approach both introduces declarative, knowledge-based technology into the involved multimedia communities and on the other hand broadens the application scope of Semantic Web Service technology in the area of general semantic service descriptions and automated program construction.

Abstract: An adaptive multimedia proxy is presented which provides (1) caching, (2) filtering, and (3) media gateway functionalities. The proxy can perform media adaptation on its own, either relying on layered coding or using transcoding mainly in the decompressed domain. A cost model is presented which incorporates user requirements, terminal capabilities, and video variations in one formula. Based on this model, the proxy acts as a general broker of different user requirements and of different video variations. This is a first step towards What You Need is What YouGet (WYNIWYG) video services, which deliver videos to users in exactly the quality they need and are willing to pay for. The MPEG-7 and MPEG-21 standards enable this in an interoperable way. A detailed evaluation based on a series of simulation runs is provided.

Abstract: Daten zu Daten werden Metadaten genannt. Sie ermöglichen die effektive Organisation, Administration und Suche nach Daten aller Arten. Demgegenüber erlaufebn Ontologen die Formalisierung der Fakten und die detailgenaue Beschreibung von Domänenwissen. In vielen Anwendungsbereichen haben sich die klassischen Metadatenformate als zu einfach und Ontologien als zu komplex erwiesen, was zu neuen Formaten führte. Hier wird ein gemeinsames Modell für solche Formate vorgestellt, das sich zur Datensuche eignet.

Abstract: High level metadata provides a way to manage, organize and retrieve multimedia data based on the actual content using content descriptions. The MPEG-7 Semantic Description Scheme provides tools for storing expressive and interpretable high level metadata. As it is currently impossible for computers to create high level metadata autonomously, users have to create the annotations manually. Generally the manual annotation of multimedia content is understood as laborious and complex task. Within this publication we assess the complexity of the annotation task for the MPEG-7 Semantic Description Scheme within a small user evaluation and the results of the evaluation are discussed.

Abstract: The year 2005 was a successful year for the MPEG and Multimedia Metadata Community. The community was founded within a first workshop in March 2005 in Klagenfurt, Austria, initiated and organized by Harald Kosch. A second workshop, which took place at the I-Know 05, the International Conference for Knowledge Management 2005 in Graz, Austria, was organized by Mathias Lux and Michael Granitzer to enlarge the community and to plan future joint activities. With a third workshop at the RWTH Aachen, Germany, organized by Marc Spaniol and Ralf Klamma, the community grew further, aims of the community were clarified and the schedule for 2006 was developed. Within the three workshops a lot of topics and projects have been discussed. The JUKM special issue on the MPEG and Multimedia Metadata Community Workshop Results 2005 aims to distribute results of community discussions and projects of the community members. The contributions to this issue have been presented by at least one of the authors at one of the above mentioned workshops. The discussion of the community has been integrated and a scientific paper has been generated. The publication has then been peer reviewed by community members. Two different types of contributions have been accepted. Technical notes are smaller in size, but present valuable partial results of ongoing research. Full papers provide more in depth discussion of applications and approaches as well as results and conclusions. From the various presentations of the three workshops in 2005 six topics have been selected for publication, whereas only the last contribution is not a full paper but a technical note.

Abstract: The ISO/IEC Motion Picture Group (MPEG) issued in 2002 a standard, called MPEG-7, which enables the content description of multimedia data in XML. The standard supports applications to exchange, identify and filter multimedia contents based on MPEG-7 descriptions. However, especially mobile applications that deal with MPEG-7 suffer from limited bandwidth, low computational power and limited battery life. In this document we describe an index system that allows filter mechanisms and random access to encoded MPEG-7 streams and which overcome the limitation of the network and the consuming terminal. Encoding is applied in order to reduce the data rate of the XML documents to be transmitted. The indexed parts of the encoded streams can be accessed without the need to deserialize the complete stream. Furthermore, the system is evaluated and results of the experimental evaluation are discussed.

Abstract: Abstract Personalized delivery of multimedia content over the Internet opens new business perspectives for future multimedia applications and thus plays an important role in the ongoing MPEG-7 and MPEG-21 multimedia standardization efforts. Based on these standards, next-generation multimedia services will be able to automatically prepare the digital content before delivery according to the client’s device capabilities, the network conditions, or even the user’s content preferences. However, these services will have to deal with a variety of different end user devices, media formats, as well as with additional metadata when adapting the original media resources. In parallel, an increasing number of commercial or open-source media transformation tools will be available, capable of exploiting such descriptive metadata or dealing with new media formats; thus it is not realistic that a single tool will support all possible transformations. In this paper, we present a novel, fully knowledge-based approach for building such multimedia adaptation services, addressing the above mentioned issues of openness, extensibility, and concordance with existing and upcoming standards. In our approach, the original media is transformed in multiple adaptation steps performed by an extensible set of external tools, where the construction of adequate adaptation sequences is solved in an Artificial Intelligence planning process. The interoperability issue is addressed by exploiting standardized Semantic Web Services technology. This technology allows us to express tool capabilities and execution semantics in a declarative and well-defined form. In this context, existing multimedia standards serve as a shared domain ontology. The presented approach was implemented and successfully evaluated in an official ISO/IEC MPEG (Moving Picture Experts Group) Core Experiment and is currently under further evaluation by the standardization body.

Abstract: More and more data are structured, stored, and sent over a networ using the Extensible Markup Language (XML) language. There are, however, concerns about the verbosity of XML in such a way that it may restrain further adoption of the language, especially when exchanging XML-based data over heterogeneous networks, and when it is used within constrained (mobile) devices. Therefore, alternative (binary) serialization formats of the XML data become relevant in order to reduce this overhead. However, using binary-encoded XML should not introduce interoperability issues with existing applications nor add additional complexity to new applications. On top of that, it should have a clear cost reduction over the current plain-text serialization format. A first technology is developed within the ISO/IEC Moving Picture Experts Group, namely the Binary MPEG Format for XML. It provides good compression efficiency, ability to (partially) update existingXMLtrees, and facilitates random access into, and manipulation of, the binary-encoded bit stream. Another technique is based on the Abstract Syntax Notation One specification with the Packed Encoding Rules created by the ITU-T. This paper evaluates both techniques as alternative XML serialization formats and introduces a solution for the interoperability concerns. This solution and the alternative serialization formats are validated against two real-life use cases in terms of processing speed and cost reduction. The efficiency of the alternative serialization formats are compared to a classic plain text compression technique, in particular ZIP compression.

Abstract: More and more data are structured, stored, and sent over a networ using the Extensible Markup Language (XML) language. There are, however, concerns about the verbosity of XML in such a way that it may restrain further adoption of the language, especially when exchanging XML-based data over heterogeneous networks, and when it is used within constrained (mobile) devices. Therefore, alternative (binary) serialization formats of the XML data become relevant in order to reduce this overhead. However, using binary-encoded XML should not introduce interoperability issues with existing applications nor add additional complexity to new applications. On top of that, it should have a clear cost reduction over the current plain-text serialization format. A first technology is developed within the ISO/IEC Moving Picture Experts Group, namely the Binary MPEG Format for XML. It provides good compression efficiency, ability to (partially) update existingXMLtrees, and facilitates random access into, and manipulation of, the binary-encoded bit stream. Another technique is based on the Abstract Syntax Notation One specification with the Packed Encoding Rules created by the ITU-T. This paper evaluates both techniques as alternative XML serialization formats and introduces a solution for the interoperability concerns. This solution and the alternative serialization formats are validated against two real-life use cases in terms of processing speed and cost reduction. The efficiency of the alternative serialization formats are compared to a classic plain text compression technique, in particular ZIP compression.

Abstract: MPEG-21 Digital Item Adaptation (DIA) has recently been finalized as part of the MPEG-21 Multimedia Framework. DIA specifies metadata for assisting the adaptation of Digital Items according to constraints on the storage, transmission and consumption, thereby enabling various types of quality of service management. This paper provides an overview of DIA, describes its use in multimedia applications, and reports on some of the ongoing activities in MPEG on extending DIA for use in rights governed environments.

Abstract: Digital Item Adaptation (DIA) has been recently standardized as Part 7 of the MPEG-21 Multimedia Framework. This standard specifies tools enabling interoperable communication and adaptation of so-called Digital Items. The adaptation process becomes ever more difficult due to the heterogeneity of terminals and networks utilizing different types of multimedia contents encoded in various coding formats. Other aspects are the users� preferences and accessibility characteristics as well as the natural environment in which the content is consumed. This article describes how to use the tools within DIA in order to build a device and coding format independent adaptation module enabling interoperable multimedia communication.

Abstract: Multimedia is gaining ever more importance on the Internet. This increases the need for intelligent and efficient video caches. A promising approach to improve caching efficiency is to adapt videos. With the availability of MPEG-4 it is possible to develop a standard compliant proxy cache that allows fast and efficient adaptation. We propose a modular design for an adaptive MPEG-4 video proxy that supports efficient full and partial video caching in combination with filtering options that are driven by the terminal capabilities of the client. We use the native scalability operations provided by MPEG-4, the MPEG-7 standard to describe the scalability options for a video and the emerging MPEG-21 standard to describe the terminal capabilities. We restrict ourselves to full video caching. The combination of adaptation with MPEG-4, MPEG-7 and client terminal capabilities is to the best of our knowledge unique and will increase the quality of service for end users. Key words: Adaptation, MPEG-4, MPEG-7, MPEG-21, adaptive proxy, caching.

Abstract: Video adaptation is an active research area aiming at delivering heterogeneous content to yet heterogeneous devices under different network conditions. It is an important component of multimedia data management to address the problem of delivering multimedia data in distributed heterogeneous environments. This paper presents a novel method of video adaptation called segment-based adaptation. It aims at applying different reduction methods on different segments based on physical content. The video is first partitioned into homogeneous segments based on physical characteristics. Then optimal reduction methods are selected and applied on each segment with the objective of minimizing quality loss and/or maximizing data size reduction during adaptation. In addition to this new method of variation creation, the commonly used reduction methods are also implemented. To realize variation creation, a unifying framework called the Variation Factory is developed. It is extended to the Multi-Step Variation Factory, which allows intermediary videos to serve as variations and also as sources to further variations. Our proposals are implemented as part of a server component, called the Variation Processing Unit (VaPU) that generates different versions of the source and an MPEG-7 metadata document.

Abstract: Unser Tutorial gibt einen Überblick über die neuesten MPEG-Standards MPEG-7/21/A/B und streicht ihre Bedeutung für Multimedia-Datenbanken heraus.

Abstract: During its lifetime, multimedia content undergoes different stages or cycles fromproduction to consumption. Content is created, processed or modified in a postproduction stage, delivered to users, and finally, consumed. Metadata, or descriptive data about the multimedia content, pass through similar stages but with different time lines.1 Metadata may be produced, modified, and consumed by all actors involved in the content production-consumption chain. At each step of the chain, different kinds of metadata may be produced by highly different methods and of substantially different semantic value.

Abstract: The seamless access to rich multimedia content on any device and over an network, usually known as Universal Multimedia Access, requires interoperable description tools and adaptation techniques to be developed. To address the latter issue, MPEG-21 Digital Item Adaptation (DIA) introduces the Bitstream Syntax Description (BSD) framework, which provides tools for adapting multimedia content in a generic (i.e., coding format independent) way. The basic idea is to use the eXtensible Markup Language (XML) to describe the high-level structure of a binary media bitstream, to transform its description (e.g., by means of eXtensible Stylesheet Language Transformations, XSLT), and to construct the adapted media bitstream from the transformed description. This paper presents how this basic BSD framework, initially developed for non-streamed content and suffering from inherent limitations and high memory consumption of XML-related technologies such as XSLT, can be advanced and efficiently implemented in a streaming environment and on resource-constrained devices. Two different attempts to solve the inherent problems are described. The first approach proposes an architecture based on the streamed processing of SAX (Simple Application Programming Interface for XML) events and adopts STX (Streaming Transformations for XML) as an alternative to XSLT, whereas the second approach breaks a BSD up into well-formed fragments called Process Units (PUs) that can be processed individually by a standard XSLT processor. The current status of our work as well as directions for future research are given.

Abstract: Adaptation in multimedia systems is usually restricted to defensive, reactive media adaptation (often called stream-level adaptation). We argue that offensive, proactive, system-level adaptation deserves not less attention. If a distributed multimedia system cares for overall, end-to-end quality of service then it should provide a meaningful combination of both. We introduce an adaptive multimedia server (ADMS) and a supporting middleware which implement offensive adaptation based on a lean, flexible architecture. The measured costs and benefits of the offensive adaptation process are presented. We introduce an intelligent video proxy (QBIX), which implements defensive adaptation. The cost/benefit measurements of QBIX are presented elsewhere. We show the benefits of the integration of QBIX in ADMS. Offensive adaptation is used to find an optimal, user-friendly configuration dynamically for ADMS, and defensive adaptation is added to take usage environment (network and terminal) constraints into account.

Abstract: A multi-clip query requests multiple video clips. In this paper we address the multi-clip query optimization problem. We propose a new heuristics called Restricted Search Interval that maximizes clip sharing between queries and consequently reduces the workload of the video server. An adaptation of our heuristics for optimizing the response time of the query is presented as well. The experimental results show that the suggested heuristics reduces the server workload by about 68% in comparison to a classical heuristic approach.