An intra-prediction method includes: determining, by an intra-prediction apparatus, a directional intra-prediction mode for a rectangular video coding block from an extended set of directional intra-prediction modes, wherein the extended set of directional intra-prediction modes includes extended directional intra-prediction modes and conventional directional intra-prediction modes and determining, by the intra-prediction apparatus, a plurality of available reference samples based on a direction of the directional intra-prediction mode. The method further includes: intra-predicting, by the intra-prediction apparatus, pixel values of pixels of the rectangular video coding block based on the plurality of available reference samples.