Intra-mixture Prediction Mode and Enhanced Most Probable Mode Estimation for Intra Coding in H.264/AVC

H.264/AVC supports various block sizes for intra prediction to reduce spatial redundancy such as 4times4, 8times8 (FRExt only) and 16times16, and the blocks are predicted from neighboring reconstructed pixels by using directional prediction modes. The directional prediction mode indices are coded by using a predictive coding method, in which the most probable mode (MPM) is derived from neighboring macroblocks (MB). In this paper, we present intra-mixture prediction (IMP) mode for intra prediction and an enhanced estimation method for most probable mode (MPM). IMP mode supports more flexibility in intra prediction by mixing 4times4 blocks and 8times8 blocks in one macroblock, while the enhanced MPM estimation extends the number of referenced neighboring blocks and efficiently uses their prediction modes depending on their positions. Simulation results show that the combination of both proposed methods increases the BD-bitrate by up to -4.16% compared to H.264/AVC.