Method and apparatus for intra prediction

Abstract

An apparatus (500), a method of intra predicting a block of a picture, a device for encoding or decoding a picture and a non-transitory recording medium are provided. The method of intra predicting a current block includes: obtaining a predicted sample value from one or more reference sample values by using an intra prediction mode; obtaining at least one additional reference sample value in accordance with the intra prediction mode; and obtaining a thresholded additional reference sample value based on the additional reference sample value. The method also includes: calculating an additional value from the thresholded additional reference sample value; multiplying the predicted sample value by a sample weighting factor, resulting in a weighted predicted sample value; adding the additional value to the weighted predicted sample value, resulting in a non-normalized predicted sample value; and normalizing the non-normalized predicted sample value, resulting in a normalized predicted sample values. The accuracy for the intra prediction is increased.