Method and apparatus for most probable mode derivation

A method for video decoding in a decoder, comprising:

• deriving for a block encoded under an intra prediction mode, using a most probable mode (MPM) derivation process, a candidate list that includes:
• a first candidate intra prediction mode value (Mode1) that corresponds to an intra prediction mode of a neighbor block that neighbors the encoded block as a first one of the plurality of intra prediction modes, and
• a second candidate intra prediction mode value (Mode2) and a third candidate intra prediction mode value (Mode3) that are determined in accordance with a predetermined offset from the first candidate intra prediction mode value and a modulo M operation, in which M is a sum of multiple powers of 2 and not equal to 32;
• and
• determining an intra prediction mode value for the encoded block in accordance with the derived candidate list.

A video decoder for video decoding, comprising:

• circuitry configured to:
• derive for a block encoded under an intra prediction mode, using a most probable mode (MPM) derivation process, a candidate list that includes:
• a first candidate intra prediction mode value (Mode1) that corresponds to an intra prediction mode of a neighbor block that neighbors the encoded block as a first one of the plurality of intra prediction modes, and
• a second candidate intra prediction mode value (Mode2) and a third candidate intra prediction mode value (Mode3) that are determined in accordance with a predetermined offset from the first candidate intra prediction mode value and a modulo M operation, in which M is a sum of multiple powers of 2 and not equal to 32;
• and
• determine an intra prediction mode value for the encoded block in accordance with the derived candidate list.

A non-transitory computer readable medium having instructions stored therein, which when executed by a processor in a video decoder causes the processor to execute a method comprising:

• deriving for a block encoded under an intra prediction mode, using a most probable mode (MPM) derivation process, a candidate list that includes:
• a first candidate intra prediction mode value (Mode1) that corresponds to an intra prediction mode of a neighbor block that neighbors the encoded block as a first one of the plurality of intra prediction modes, and
• a second candidate intra prediction mode value (Mode2) and a third candidate intra prediction mode value (Mode3) that are determined in accordance with a predetermined offset from the first candidate intra prediction mode value and a modulo M operation, in which M is a sum of multiple powers of 2 and not equal to 32;
• and
• determining an intra prediction mode value for the encoded block in accordance with the derived candidate list.