Motion activity-based block size decision for multi-view video coding

Motion estimation and disparity estimation using variable block sizes have been exploited in multi-view video coding to effectively improve the coding efficiency, but at the expense of yielding higher computational complexity. In this paper, a fast block size decision algorithm, called motion activity-based block size decision (MABSD), is proposed. In our approach, the various motion estimation and disparity estimation block sizes are classified into four classes, and only one of them will be chosen to further identify the optimal block size within that class according to the measured motion activity of the current macroblock. The above-mentioned motion activity can be measured by the maximum city-block distance of a set of motion vectors taken from the adjacent macroblocks in the current view and its neighboring view. Experimental results have shown that compared with exhaustive block size decision, which is a default approach set in the JMVM reference software, the proposed MABSD algorithm achieves a reduction of computational complexity by 42% on average, while incurring only 0.01 dB loss in peak signal-to-noise ratio (PSNR) and 1% increment on the total bit rate.