The present disclosure provides methods and devices of intra predicting a block of a picture. The method comprises for a sample of the block: obtaining a predicted sample value from one or more reference sample values by performing intra-prediction using a DC intra-prediction mode; multiplying the predicted sample value by a sample weighting factor to produce a weighted predicted sample value; adding an additional value to the weighted predicted sample value to produce a non-normalized predicted sample value; and normalizing the non-normalized predicted sample value by an arithmetic right shift; wherein the sample weighting factor is ((2