Improved overlapped block motion compensation using adaptive weighting matrices design for 3D wavelet-based scalable video coding

Abstract

Recently, scalable video compression using three-dimensional (3D) discrete wavelet transform has become a promising competitor in the scalable video coding (SVC) field. Overlapped block motion compensation (OBMC) is considered to be a key component of most efficient block-based motion estimation and compensation technologies for 3D wavelet-based SVC. However, the conventional OBMC approach globally smoothes out the prediction intensity field with the uniform window function for all the same-sized blocks, with the result that sharp features such as blocky edges are blurred or over-smoothed in the motion-compensated prediction. In this paper, we propose an improved OBMC scheme that adopts adpative weighting matrices for the case of variable block size motion compensation. Specifically, we resort to a parametric solution in closed form to express the optimal weights for the OBMC windows, based on the spatially-variant prediction of motion vectors. For our OBMC weighting matrices, the proposed interpolation algorithm is more effective in enhancing the coding performance than the most widely used interpolation algorithms, along with both the theoretical and empirical analyses. Experimental results show significant improvement over existing successful 3D wavelet-based scalable video codecs in both objective and subjective quality.