Content Adaptation on Mobile Devices Using MPEG-21

Content authors pursue the creation of mobile content that is ubiquitous in nature, i.e. published once only but being available anywhere, anytime, on any device. However, mobile content must accommodate varying resource constraints on different devices such as reduced resolution, processing power, memory and network bandwidth. In this chapter, we discuss those issues that are pertinent to multimedia content adaptation across different devices with reference to MPEG-21's Digital Item Adaptation for mobile devices. In particular, we consider how the range of aspects that affect a mobile usage environment, i.e. network, natural environment, device and user characteristics, could be used alongside a set of user-defined limitation and optimization constraints, to adapt content and thereby maximize quality of service.