On generalizing the estimation-theoretic framework to scalable video coding with quadtree structured block partitions
Scalable video coding suffers from the under-utilization of base layer information, where usually only the reconstruction in the base layer is used for enhancement layer prediction. Prior work from our lab proposed an optimal estimation-theoretic (ET) approach for quality scalable coding, wherein the estimates are obtained by utilizing all the available information from base layer quantization interval and enhancement layer distribution for transform coefficients. While this approach was proposed for fixed block size encoding, modern codecs employ variable block size quadtree structured partitioning, which results in different partitions at base layer and enhancement layer based on the rate-distortion trade-off, thus makes the base layer information not directly usable in the enhancement layer. Other new tools such as hybrid transform and the rate-distortion optimized quantizer (RDOQ) also have an impact on the information available for optimal estimation. In this paper, we generalize the ET framework for quality scalable video coding to account for the quadtree structured partitioning, hybrid transform and the RDOQ adjustment. Experimental evidence is provided for consistent coding gains over standard SHVC.