Quantizer design for exploiting common information in layered coding
Today's diverse data consumption devices and heterogeneous network conditions require content to be coded at different quality levels. Conventional scalable coding, which generates hierarchical layers that refine quality incrementally, introduces a performance penalty, as most sources are not successively refinable at finite delays for the distortion measure employed and the combination of rates at each layer. On the other hand encoding different copies at required quality levels is clearly wasteful in resources. We previously proposed a common information based framework with a relaxed hierarchical structure to generate common and individuals bit-streams for different quality levels, to provide the flexibility of operating at points between conventional scalable coding and independent coding. In this paper we propose a quantizer design technique for this layered coding framework, which enables extracting common information between two quality levels with negligible performance penalty. Experimental results for Laplacian sources, which are prevalent in practical multimedia systems, substantiate the effectiveness of our proposed technique.