A Fast Mode Decision Scheme with Variable Block Sizes in H.264/AVC

H.264/AVC the latest international video coding standard achieves higher compression efficiency than previous video coding standards such as MPEG-4 and H.263. However, this performance gain comes at the cost of an increased computational complexity. To achieve a high coding efficiency, H.264/AVC employs complex mode decision techniques based on rate-distortion optimization, the computational complexity is very high. This is a major bottleneck for the H.264/AVC in real-time application. Inter-frame prediction coding is a more important part in H.264/AVC. In order to reduce the computational complexity, a fast mode decision algorithm is proposed for Inter-frame in H.264/AVC video coding standard in this paper. With the new algorithm, the amount of computation involved in the motion estimation and mode decision can be substantially reduced. Simulation results show that the proposed algorithm can reduce 56.52% on average of the total encoding time, with a slight increase in bit rate and a negligible PSNR drop.