Efficient block mode decision and prediction mode selection for intra prediction in H.264/AVC high profile

Abstract

This paper presents an efficient method in deciding macro-block mode and selecting prediction mode for intra prediction in H.264/AVC high profile. H.264/AVC supports nine intra prediction modes for luminance 4x4 and 8x8 blocks. The predictors include 8 directional modes and intra DC mode, which is non-directional mode. For luminance 16x16 blocks, the following 4 intra prediction modes are used: Vertical, Horizontal, DC and Plane mode. To select the best prediction mode, rate-distortion costs of all possible prediction modes are calculated exhaustively. Thus, intra prediction process in H.264/AVC has high computational complexity. Especially, in high profile, it is extremely large since luminance 8x8 blocks are added as candidate macro-block mode. To overcome this issue, we proposed efficient macro-block mode decision and prediction mode selection for intra prediction in H.264/AVC high profile. We employed variance of current macro-block to decide macro-block mode and proposed improved prediction mode selection to select intra prediction mode. The experimental results of proposed method show that the proposed algorithm reduces encoding time 83.194% on average (up to 87.081%) without noticeable rate distortion performance loss.