Supplementary Samples Derivation for Intra Prediction

A decoder comprising:

• one or more processors;
• and
• memory storing instructions that, when executed by the one or more processors, cause the decoder to:
• determine an inverse angle of an intra prediction mode based on:
• an indication of a precision of the intra prediction mode, wherein the indication indicates the precision of the intra prediction mode from at least two different precisions;
• and
• an entry of a lookup table (LUT) for inverse angles, wherein the indication indicates the LUT from at least two LUTs corresponding to the at least two different precisions, respectively;
• determine a fractional projected displacement by dividing a product, of the inverse angle and a position of a supplementary sample, by a value used for each of the at least two different precisions;
• calculate the supplementary sample based on an integer part of the fractional projected displacement;
• and
• decode a current block by applying the intra prediction mode to a line of reference samples, comprising the supplementary samples, to generate a prediction block for the current block.

A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of a decoder, cause the decoder to:

• determine an inverse angle of an intra prediction mode based on:
• an indication of a precision of the intra prediction mode, wherein the indication indicates the precision of the intra prediction mode from at least two different precisions;
• and
• an entry of a lookup table (LUT) for inverse angles, wherein the indication indicates the LUT from at least two LUTs corresponding to the at least two different precisions, respectively;
• determine a fractional projected displacement by dividing a product, of the inverse angle and a position of a supplementary sample, by a value used for each of the at least two different precisions;
• calculate the supplementary sample based on an integer part of the fractional projected displacement;
• and
• decode a current block by applying the intra prediction mode to a line of reference samples, comprising the supplementary samples, to generate a prediction block for the current block.