Rik Van de Walle

A performance evaluation of MPEG-21 BSDL in the context of H.264/AVC

H.264/AVC is a new specification for digital video coding that aims at a deployment in a lot of multimedia applications, such as video conferencing, digital television broadcasting, and internet streaming. This is for instance reflected by the design goals of the standard, which are about the provision of an efficient compression scheme and a network-friendly representation of the compressed data. Those requirements have resulted in a very flexible syntax and architecture that is fundamentally different from previous standards for video compression. In this paper, a detailed discussion will be provided on how to apply an extended version of the MPEG-21 Bitstream Syntax Description Language (MPEG-21 BSDL) to the Annex B syntax of the H.264/AVC specification. This XML based language will facilitate the high-level manipulation of an H.264/AVC bitstream in order to take into account the constraints and requirements of a particular usage environment. Our performance measurements and optimizations show that it is possible to make use of MPEG-21 BSDL in the context of the current H.264/AVC standard with a feasible computational complexity when exploiting temporal scalability.

Advanced mobile multimedia applications: Using MPEG-21 and Time-Dependent metadata

While the price of mobile devices is dropping quickly, the set of features and capabilities of these devices is advancing very dramatically. Because of this, new mobile multimedia applications are conceivable, also thanks to the availability of high speed mobile networks like UMTS and Wireless LAN. However, creating such applications is still difficult due to the huge diversity of features and capabilities of mobile devices. Software developers also have to take into account the rigorous limitation on processing capabilities, display possibilities, and the limited battery life of these devices. On top of that, the availability of the device resources fluctuates strongly during execution of an application, directly and violently influencing the user experience, whereas equivalent fluctuations on traditional desktop PCs are far less prominent. Using new technology like MPEG-4, -7 and -21 can help application developers to overcome these problems. We have created an MPEG-21-based Video-on-Demand application optimized for mobile devices that is aware of the usage environment (i.e., user preference, device capabilities, device conditions, network status, etc.) of the client and adapts the MPEG-4 videos to it. The application is compliant with the Universal Multimedia Access framework, supports Time-Dependent Metadata, and relies on both MPEG-4 and MPEG-21 technology.

MPEG-21 Session Mobility in a Broadcasting Environment

Interactive digital television (iDTV) will take an important role in our future life. The world of (digital) television is based on a broadcasting environment. The impact of that kind of environment is very important during the development of applications for digital television. Another remarkable trend of the last years is the growth of new (mobile) devices that can interact with multimedia content like GSMs and Personal Digital Assistants (PDA). Each of those devices has different network and terminal capabilities. Nowadays, television producers not only want to create programs for television but they also want to offer their content to other devices and to the World Wide Web (WWW). In this paper, we will talk about session mobility when we mean switching between different devices. In this paper, we will discuss what kind of problems arises during the development of session mobility in a broadcasting environment. As implementation platform, we will use Multimedia Home platform as middleware of the set top box. For the realization of session mobility, we also use a part of the MPEG-21 technology.

An analysis of packaging formats for complex digtal objects: review of principles

During recent years, the number of organizations making digital information available has massively increased. This evolution encouraged the development of standards for packaging and encoding digital representations of complex objects (such as a digital music albums or digitized books and photograph albums). The primary goal of this article is to offer a method to compare these packaging standards and best practices tailored to the needs of the digital library community and the rising digital preservation programs. The contribution of this paper is the definition of an integrated reference model, based on both the OAIS framework and some additional significant properties that affect the quality, usability, encoding and behavior of the digital objects.