Intra block prediction using first-second row non-directional samples in HEVC video coding

Abstract

This paper presents two intra prediction algorithms in High Efficiency Video Coding (HEVC) encoder for reducing the computational complexity and increase the encoding speed. The first algorithm takes advantage of the high spatial correlation among neighboring pixels to substitute the reference samples as the first row or first and second rows of the current block to be predicted, while the pixels intensities in the remaining rows or columns as in the case of horizontal predictions, are extrapolated as usual. Secondly, due to spatial correlations in video block data among adjacent blocks, it has been established that the intra prediction mode of the current block has a high probability of being a member of the most probable mode set or a slight variation of one of the most probable modes. These algorithms are combined and implemented on the HM16 reference software, and show speedup of 23.4% and 22.7% in encoding time using the all-intra-main configuration, with minimal reduction in bitrate of 0.21% and 0.22% respectively.