A fast intramode decision algorithm for H.264/AVC

In the latest video coding standard H.264/AVC, coding efficiency is improved by introducing the intra-prediction. At the same time, it brings extremely high computational complexity and makes it a bottleneck for a real-time implementation of the H.264/AVC encoder. A fast and efficient intra-prediction mode decision algorithm is proposed in this paper. Firstly, it makes a choice between the INTRA_4 × 4 and INTRA_16 × 16 based on the complexity of the image. And then it adopts the high correlation of the prediction mode between current 4 × 4 block and adjacent blocks, strong correlation between the sum of absolute transform difference (SATD) and rate distortion (RD) performance to skip some unlikely prediction modes efficiently. So it reduces the intra-prediction complexity greatly. Experimental results show that the proposed algorithm can save the encoding time up to 65.5% averagely without noticeable loss of coding efficiency.