Hybrid angular intra/template matching prediction for HEVC intra coding

In the latest HEVC video coding standard, angular intra prediction (AIP) applies 35 modes including 33 angular modes which can handle blocks with direction information well, and other 2 modes (DC and planar) which are used to predict smooth blocks. However, for blocks with complex texture, these modes may not give good predictions. Some complex blocks can be predicted well by template matching prediction (TMP) which was proposed to predict blocks having similar patterns in the coded regions of the same frame without the cost of large overheads. In this paper, a novel hybrid AIP/TMP is proposed to improve the prediction efficiency. Experimental results show that the proposed method can achieve a coding gain of about 2.5% for high resolution sequences on average compared to the AIP in HEVC. The gain can be up to 4.2%.