Fast and efficient motion estimation using diamond zonal-based algorithms

Motion estimation has always been an important part of video encoding syste ms because it can reduce temporal redundancy effectively and thus has signi ficant impact on the bit rate and the output visual quality of the encoded sequence. Unfortunately, when using the brute-force full search algorithm, motion estimation consumes a very large portion of the encoding time. Previ ously, several algorithms have been proposed which try to reduce complexity , usually, with a significant loss in visual quality. Based on the diamond zonal search framework we introduced recently, we propose in this paper a n ovel algorithm called advanced diamond zonal search (ADZS), which was submi tted to and well received by the Moving Pictures Experts Group (MPEG) stand ard committee for possible inclusion as an encoder optimization tool. ADZS was criticized in MPEG for using fixed thresholds, which may not be suitabl e for all video sequences. To address this issue, we further propose a thre shold-adaptive version called threshold-adaptive advanced diamond zonal sea rch (TAADZS). Simulation results verify the superior performance of ADZS an d TAADZS over other fast algorithms and the robustness of TAADZS over ADZS.