Computational complexity reduction algorithm for inter mode prediction in video coding

H.264, MPEG-4 Part 10, is the latest digital video coding standard that achieves very high data compression by using several new coding features. One of the new feature is variable block sizes for inter frame coding to increase compression efficiency. However, to achieve this, the H.264 encoder employs a complex mode decision technique based on rate-distortion optimization (RDO) that requires high computational complexity, which significantly increases the encoder complexity. In this paper, we propose a classified region algorithm (CRA) that analyzes the spatial and temporal homogeneity of the block by using cross differences to reduce the number of modes that are required for RDO calculation in inter mode decision. The proposed low computational complexity algorithm significantly reduces the inter mode computations without affecting the video quality. The experimental results show that the proposed method is able to reduce the complexity by up to 67% on average with negligible degradation in subjective and objective quality.