On an evaluation of transformation languages in a fully XML-driven framework for video content adaptation

Bitstream Structure Descriptions (BSDs) allow taking the complexity of transforming scalable bitstreams from the compressed domain to the semantic domain. These descriptions are an essential part of an XUL-driven video adaptation framework. The performance of a BSD transformation engine is very important in such an architecture. This paper evaluates the efficiency of XML-based transformation languages in our video adaptation framework. XSLT, STX, and a hybrid solution are compared to each other in terms of execution times, memory consumption, and user-friendliness. Our experiments show that STX is the preferred solution when speed and low-memory are important. The hybrid solution is competitive in terms of memory consumption and is more user-friendly than STX. Although XSLT is relative fast, its memory consumption is very high

XML-driven exploitation of combined scalability in scalable H.264/AVC bitstreams

The heterogeneity in the contemporary multimedia environments requires a format-agnostic adaptation framework for the consumption of digital video content. Scalable bitstreams can be used in order to satisfy as many circumstances as possible. In this paper, the scalable extension on the H.264/AVC specification is used to obtain the parent bitstreams. The adaptation along the combined scalability axis of the bitstreams is done in a format-independent manner. Therefore, an abstraction layer of the bitstream is needed. In this paper, XML descriptions are used representing the high-level structure of the bitstreams by relying on the MPEG-21 Bitstream Syntax Description Language standard. The exploitation of the combined scalability is executed in the XML domain by implementing the adaptation process in a Streaming Transformation for XML (STX) stylesheet. The algorithm used in the transformation of the XML description is discussed in detail in this paper. From the performance measurements, one can conclude that the STX transformation in the XML domain and the generation of the corresponding adapted bitstream can be realized in real time

MPEG-21 session mobility for heterogeneous devices

Nowadays, multimedia is becoming an important part of our live. Every day, the number of people that are having multimedia experiences is augmenting. To allow this growth in multimedia experiences, a new set of devices has been developed. Each of those devices has different terminal and network capabilities, or even different functionalities. As a result of this growing variety of devices, more and more people tend to use several devices for multimedia consumption. Having a wide set of devices for multimedia experiences, results in a demand for seamless switching between devices, better known as session mobility. In this paper, we discuss how session mobility can be realized between heterogeneous devices using MPEG-21 technology. First, we give an overview of the difficulties that occur when doing session mobility between heterogeneous devices. After this problem statement, we give a detailed discussion on how to overcome those difficulties by using MPEG-21. Throughout this paper, we will demonstrate how different parts of MPEG-21 can be integrated into a complete MPEG-21 compliant multimedia framework that facilitates session mobility between heterogeneous devices

Fully format agnostic media resource adaptation using an abstract model for scalable bitstreams

Due to the increasing heterogeneity in network and terminal capabilities, the delivery of multimedia content has become an important issue today. In order to avoid offering multiple versions of the same media resource, a transparent approach under the form of scalable coding is needed for multimedia delivery systems. This paper proposes a fully format agnostic adaptation engine for scalable bitstreams by relying on an abstract model for these bitstreams. The adaptation technique is implemented by making use of the MPEG-21 Digital Item Adaptation specification. The approach is validated for five different scalable coding formats. Experimental results show that our fully format agnostic adaptation node customizes scalable bitstreams in real time (at a speed of more than 100 Mbit/s)