Exploiting Partial Distortion Elimination in the Sum of Absolute Differences for Energy-Efficient HEVC Integer Motion Estimation

Integer Motion Estimation (IME) is an important tool that explores the temporal redundancies in video encoders. It stands out among the most time-consuming and memory intensive tasks in the encoding process. Most of the IME processing is spent on the computation of similarities between pixel blocks, usually using the Sum of Absolute Differences (SAD) as block selection criterion. Designing high-throughput and energy-efficient SAD units is an effective way of increasing the performance of IME architectures. This paper proposes an optimization of SAD units considering the state-of-the-art High Efficiency Video Coding (HEVC) standard, which avoids the computation of candidates that will surely not be selected in the IME search, by applying Partial Distortion Elimination (PDE). The method achieves, without any loss in coding performance, an average reduction of 16.41% and 11.64% in the energy consumption for 1080p and 2160p (4K) videos, respectively, when compared to an HEVC SAD implementation without PDE.