MPEG-21 - What does it bring to Audio?

Despite widespread interest, electronic commerce for audio currently still presents a major challenge with regard to aspects such as security, transaction handling, interoperability of devices and services and end user experience. While many component technologies are already available addressing certain aspects of this scenario, a seamless integration of these functionalities into one unified framework has not been established yet. In response to this problem, the vision of the ongoing MPEG-21 standardization effort is to define a multimedia framework enabling transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities. This paper attempts to provide an overview over the concepts and the current status of the MPEG-21 framework and discusses its relevance for future electronic distribution and commerce of audio.