Algorithm optimisation and hardware implementation of interprediction mode decision

Abstract

High efficiency video coding is the most widely used video coding standard. It has higher coding performance compared with its predecessor, H.264, but it also has higher computational complexity. Interprediction is the most computationally intensive part of the entire video encoding process. Selecting the optimal interprediction mode by the rate–distortion cost calculation function requires substantial complex calculation and memory access, thus greatly increasing the difficulty of real-time hardware encoding. This study proposes to replace the traditional complex error square sum calculation with an estimation method for distortion and rate. The estimation of distortion uses the Hadamard-transformed sum of absolute transformation difference instead of the complex calculation of the sum of squared difference, whereas the estimation of rate is obtained by weighting the number of prediction units (PUs). The experiment proves that the proposed interprediction rate–distortion cost calculation model can greatly reduce computational complexity when BD-rate is increased by 3.02%. In hardware implementation, the value of rate can be obtained by indexing the number of PUs, and the resource expenditure is small.