Reduced 4×4 block intra prediction modes using directional similarity in H.264/AVC

This paper presents a low complexity 4×4 block intra prediction algorithm for H.264/AVC by reducing the original 9 prediction modes to 3 sub-sampled ones. The proposed algorithm takes advantage of the directional similarity found in the original ones to predict the most probable mode. The simulation result shows that the proposed algorithm can the computational complexity around 50∼70% while maintaining similar SNR of Y, U, and V as compared with the full search algorithm.