An Improved Diagonal Up-left Prediction Method for HEVC Intra Coding

Abstract

Intra prediction of HEVC supports up to 33 directional modes compared to 8 such modes in H.264/AVC. Employing many more prediction orientations, HEVC can reflect the directional properties of a coding picture more accurately. Although these directional modes are well designed and show good coding performance, the directional prediction strategy can still be improved. In this paper, an alternative diagonal up-left prediction mode is introduced. Two diagonal left reference samples are utilized to predict the mode with appropriate prediction weights. With negligible computing cost, the proposed prediction mode achieves better coding performance than the same directional mode of HEVC.