Gradient Based Interpolation For Intra Angular Prediction In Hevc

In the High Efficiency Video Coding (HEVC), the predicted pixels generated by the intra angular prediction are the same along the prediction direction. In this paper, an improved gradient based interpolation for intra angular prediction is proposed. The gradient is generated by both row and column reference samples according to the prediction direction and changed dynamically for each pixel. It is appended to the original intra prediction process to improve the performance of interpolation. This method describes the features of directional gradient changes, which improves the performance of intra interpolation. The method achieves up to 1.90% BD-Rate reduction and ignorable decoding time increase under intra main configuration based on HM 16.7.