Intra mode coding

An apparatus for controlling intra prediction for decoding of a video sequence, the apparatus comprising:

• at least one memory configured to store computer program code;
• and
• at least one processor configured to access the at least one memory and operate according to the computer program code, the computer program code comprising:
• determining code configured to cause the at least one processor to determine a ratio of a width to a height of a coding unit;
• adding code configured to cause the at least one processor to, based on the determined ratio being different than one, add, to a table including a plurality of intra prediction modes corresponding to intra prediction angles, first wide angles toward a bottom-left edge of the coding unit, second wide angles toward a top-right edge of the coding unit, and additional intra prediction modes respectively corresponding to the first wide angles and the second wide angles;
• and
• selecting code configured to cause the at least one processor to select, for decoding the video sequence, one of the plurality of intra prediction modes and the additional intra prediction modes added to the table,
• wherein each of the intra prediction angles included in the table has an angular direction α with tan(α) equal to {0/32, 1/32, 2/32, 3/32, 4/32, 6/32, 8/32, 10/32, 12/32, 14/32, 16/32, 18/32, 20/32, 23/32, 26/32, 29/32, 32/32}.

A non-transitory computer-readable storage medium storing instructions that cause a processor to:

• determine a ratio of a width to a height of a coding unit;
• based on the determined ratio being different than one, add, to a table including a plurality of intra prediction modes corresponding to intra prediction angles, first wide angles toward a bottom-left edge of the coding unit, second wide angles toward a top-right edge of the coding unit, and additional intra prediction modes respectively corresponding to the first wide angles and the second wide angles;
• and
• select, for decoding a video sequence, one of the plurality of intra prediction modes and the additional intra prediction modes added to the table,
• wherein each of the intra prediction angles included in the table has an angular direction α with tan(α) equal to {0/32, 1/32, 2/32, 3/32, 4/32, 6/32, 8/32, 10/32, 12/32, 14/32, 16/32, 18/32, 20/32, 23/32, 26/32, 29/32, 32/32}.