Method and apparatus of novel intra prediction with combinations of reference lines and intra prediction modes in video coding system

Abstract

A method and apparatus of video coding using joint prediction by combining an intra prediction mode with one or more reference lines. According to the method, a set of joint prediction candidates are determined where each joint prediction candidate corresponds to a combination of an intra prediction mode from a group of intra prediction mode candidates and one or more reference samples in one or more reference lines from a group of reference line candidates. A target joint prediction candidate is determined from the set of joint prediction candidates where said one or more reference samples are used for assisting determining the target joint prediction candidate. The current block is encoded or decoded by using one or more predictors comprising the target joint prediction candidate.