HEVC Fractional Motion Estimation complexity reduction for real-time applications

This paper presents a compression analysis about the High Efficiency Video Coding (HEVC) standard targeting a computational effort reduction at the scope of the motion estimation (ME). Restricting the Prediction Units (PUs) - among a total of 24 sizes - to the 4 square-shaped sizes in the HEVC interframes prediction, it is possible to reduce in 74% the number of operations at the cost of 4% increase in the bit-rate, considering the Y-BD-Rate metric. Based on this evaluation, a simple hardware architecture is proposed to implement the Sum of Absolute Differences (SAD) used in the Fractional Motion Estimation (FME). The proposed architecture is able to calculate SAD with a rate of 30 Full HD (1920×1080) frames per second, requiring a frequency of 1.17GHz. It represents a 63% frequency reduction compared to a scenario where all 24 PU sizes are evaluated.