Rate-constrained successive elimination of Hadamard-based SATDs

The efficiency improvements achieved by new video coding standards come at the cost of a huge increase in the encoder computational complexity. Paradoxically, such increasing complexity is commonly addressed by methods that have an adverse effect on coding efficiency. In this work, we propose a method to reduce the complexity of HEVC Hadamard ME, without compromising coding efficiency. Our method relies on a new metric named Absolute First Difference (AFD), which is able to eliminate impossible candidates using only a few operations. Despite its simplicity, AFD filters an average of 13.52% of SATDs in the HEVC reference model (HM), without reducing coding efficiency. Moreover, our method is able to filter up to 37.9% of SATDs for video conferencing and up to 64% for screen content.