Abstract: XML-based metadata is widely adopted across the different communities and plenty of commercial and open source tools for processing and transforming are available on the market. However, all of these tools have one thing in common: they operate on plain text encoded metadata which may become a burden in constrained and streaming environments, i.e., when metadata needs to be processed together with multimedia content on the fly. In this paper we present an efficient approach for transforming such kind of metadata which are encoded using MPEG's Binary Format for Metadata (BiM) without additional en-/decoding overheads, i.e., within the binary domain. Therefore, we have developed an event-based push parser for BiM encoded metadata which transforms the metadata by a limited set of processing instructions – based on traditional XML transformation techniques - operating on bit patterns instead of cost-intensive string comparisons.

Abstract: The information revolution of the last decade has resulted in a phenomenal increase in the quantity of multimedia content available to an increasing number of different users with different preferences who access it through a plethora of devices and over heterogeneous networks. In order to address the amount of different content types, MPEG-21 Digital Item Adaptation (DIA) introduces interoperable description tools which enable coding format independent adaptation. Bandwidthefficient transport of the content to terminals with different capabilities and through a variety of access networks with various characteristics requires adaptation facilities not only on the server but also within the network. In this paper we present transport mechanisms for MPEG-21-based metadata enabling generic adaptation within the network. Three different transport mechanisms for delivering this metadata in conjunction with the corresponding multimedia content are evaluated and a payload format for the transport of this metadata is presented. Furthermore, we performed measurements which demonstrate the bandwidth benefits of our distributed adaptation approach compared to server-centric adaptation in a multicast scenario. Finally, we applied various encoding formats for the metadata which further reduces the metadata overhead.

Abstract: The growing demand for multimedia information by different types of users equipped with a large variety of devices and connecting through different kinds of networks results in an increasing amount of different multimedia formats. Research is currently concentrating on the adaptation of the contents in order to provide Universal Multimedia Access (UMA) for the content consumer. But this does not solve the problem of the content provider, who still has to signal this variety of different multimedia formats to the consumer. In this contribution, we show a way to stream any type of multimedia format based on generic hint information. This hint information is based on a generic bit stream syntax description (gBSD) which is used for format-independent content adaptation within the MPEG-21 Multimedia Framework. Ultimately, this can lead to a frame-work which allows generic streaming and generic adaptation anywhere in the network.

Abstract: Due to the heterogeneity of the current terminal and network infrastructures, multimedia content needs to be adapted to specific capabilities of these terminals and network devices. Furthermore, user preferences and user environment characteristics must also be taken into consideration. The problem becomes even more complex by the diversity of multimedia content types and encoding formats. In order to meet this heterogeneity and to be applicable to different coding formats, the adaptation must be performed in a generic and interoperable way. As a response to this problem and in the context of MPEG-21, we present an approach which uses XML to describe the high-level structure of a multimedia resource in a generic way, i.e., how the multimedia content is organized, for instance in layers, frames, or scenes. For this purpose, a schema for XML-based bitstream syntax descriptions (generic Bitstream Syntax Descriptions or gBSDs) has been developed. A gBSD can describe the high-level structure of a multimedia resource in a coding format independent way. Adaptation of the resource is based on elementary transformation instructions formulated with respect to the gBSDs. These instructions have been separated from the gBSDs in order to use the same descriptions for different adaptations, e.g., temporal scaling, SNR scaling, or semantic adaptations. In the MPEG-21 framework, those adaptations can be steered for instance by the network characteristics and the user preferences. As a result, it becomes possible for coding format agnostic adaptation engines to transform media bitstreams and associated descriptions to meet the requirements imposed by the network conditions, device capabilities, and user preferences.

Abstract: Multimedia is gaining ever more importance on the Internet. This increases the need for intelligent and efficient video caches. Typical Web proxies were not designed to efficiently support the caching of videos. 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 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 and use the emerging MPEG-7 standard to describe the scalability options for a video. The proxy parses the MPEG-7 description and decides, based on this description and the terminal capabilities of the client, which adaptation step to choose. Simple MPEG-4 audio-visual streams are supported by filter operations in the compressed domain that realize several temporal scaling algorithms and color reduction. In this paper, we will 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.

Abstract: This work introduces a framework for adapting MPEG-4 intra- and inter-Elementary Streams and for encoding the results in an MPEG-7 stream to be used for resource adaptation on the delivery path to the user.