Content adaptation currently appears to be the key solution to support the quality of service (QoS) for multimedia services over heterogeneous environments. In this chapter, we study modality conversion as an important adaptation method. We point out two main challenging issues of the problem of modality conversion: (1) the quantification of the content value (quality) when contents are drastically scaled and/or converted to other modalities and (2) the method to accurately decide the modality and content value for each object given that quantification. Accordingly, we will present in detail the solutions as well as the open questions to these two issues. Moreover, we discuss the benefits and obstacles as well as future trends of modality conversion in realizing the goal of universal multimedia access.
Cost of in-network adaption of MC-EZBC for universal multimedia access
