Intra-prediction apparatus for extending a set of predetermined directional intra-prediction modes

An intra-prediction method for extending a set of predetermined directional intra-prediction modes of a rectangular video coding block, each predetermined directional intra-prediction mode of the set of predetermined directional intra-prediction modes being associated with a predetermined direction within a predetermined directional range, the intra-prediction method comprising:

• determining a width and a height of the video coding block;
• determining an aspect ratio of the rectangular video coding block on the basis of the width and the height;
• determining an extension directional intra-prediction mode upon the basis of the aspect ratio of the rectangular video coding block, wherein the extension directional intra-prediction mode is within a complementary angle range (α), the complementary angle range (α) being associated with a complementary directional range different from the predetermined directional range;
• and
• intra-predicting pixel values of pixels of the rectangular video coding block on the basis of the extension directional intra-prediction mode.

A non-transitory computer readable medium comprising a program code for performing, when executed on a computer, an intra-prediction method for extending a set of predetermined directional intra-prediction modes of a rectangular video coding block, each predetermined directional intra-prediction mode of the set of predetermined directional intra-prediction modes being associated with a predetermined direction within a predetermined directional range, the intra-prediction method comprising:

• determining a width and a height of the video coding block;
• determining an aspect ratio of the rectangular video coding block on the basis of the width and the height;
• determining an extension directional intra-prediction mode upon the basis of the aspect ratio of the rectangular video coding block, wherein the extension directional intra-prediction mode is within a complementary angle range (α), the complementary angle range (α) being associated with a complementary directional range different from the predetermined directional range;
• and
• intra-predicting pixel values of pixels of the rectangular video coding block on the basis of the extension directional intra-prediction mode.