An approach of dynamically forming an acceptable transcoding path by a search algorithm based on a context-free grammar in a MPEG21 DIA

In order to access the multimedia content in a server via mobile devices, the content should be adapted and streamed into the mobile device according to the system environment and user preferences. In this paper, we propose a method of finding a transcoding path that is a sequence of multiple unit transcoders based on the theory of a Context-Free Grammar (CFG). Algorithms to generate CFG production rules and to find one acceptable transcoding path are also suggested. Finally the experimental results are described. The suggested algorithms can be utilized in a MPEG21 digital item adaptation for a resource adaptation engine.