Improved side information generation using adaptive overlapped block motion compensation and higher-order interpolation

This work addresses the twin issues of overlapping and blocking artifacts in Distributed Video Coding side information (SI). These both emanate from the block matching algorithm (BMA) used for motion vector (MV) generation rather than pixel-wise processing. In temporal correlation exploitation and particularly in the formulation of higher-order piecewise temporal trajectory interpolation (HOPTTI), BMA has been applied due to its speed and simplicity. While HOPTTI has exhibited superior SI quality to other BMA-based algorithms, the adaptive overlapped block motion compensation (AOBMC) algorithm reduces the overlapping and blocky artifacts by adjusting the coefficients of a raised cosine overlapped window based on neighboring MV reliability. The aim of this paper is to investigate the benefits of combining HOPTTI with AOBMC. A mode switching (MS) mechanism is introduced to exploit the spatial-temporal correlation in a sequence to select between frames which will benefit from combining HOPTTI with AOBMC via a matching criterion. Experimental results confirm that selectively combining HOPTTI with AOBMC gives better SI quality, with on average up to 1.8dB improvement compared to using only HOPTII, and up to 3.6dB improvement over existing AOBMC-based algorithms.