Encoding and decoding method and storage medium

An encoding method, applicable to an encoder and comprising:

• determining a prediction mode parameter;
• determining a matrix-based intra prediction (MIP) parameter of a current block, in response to the prediction mode parameter indicating that MIP is used for the current block to determine an intra prediction value, wherein the MIP parameter comprises a size parameter of the current block;
• determining an intra prediction block of the current block according to the MIP parameter, and calculating a residual block obtained by subtracting the intra prediction value from the current block;
• determining a mapping mode of a low-frequency non-separable transform (LFNST) transform set using decoder side intra mode derivation (DIMD) in response to the size parameter not satisfying a first preset condition, wherein the mapping mode of the LFNST transform set is an intra prediction mode mapped to the LFNST transform set;
• selecting, according to the mapping mode of the LFNST transform set, one LFNST transform kernel candidate set from a plurality of LFNST transform kernel candidate sets, determining an LFNST transform kernel used for the current block from the selected LFNST transform kernel candidate set, and setting an LFNST index and signalling the LFNST index into a video bitstream;
• and
• transforming the residual block using the LFNST transform kernel.

A non-transitory computer-readable storage medium storing a computer program and a bitstream, wherein when executed by a processor, the computer program causes the processor to implement an encoding method to generate the bitstream, the encoding method comprising:

• determining a prediction mode parameter;
• determining a matrix-based intra prediction (MIP) parameter of a current block, in response to the prediction mode parameter indicating that MIP is used for the current block to determine an intra prediction value, wherein the MIP parameter comprises a size parameter of the current block;
• determining an intra prediction block of the current block according to the MIP parameter, and calculating a residual block obtained by subtracting the intra prediction value from the current block;
• determining a mapping mode of a low-frequency non-separable transform (LFNST) transform set using decoder side intra mode derivation (DIMD) in response to the size parameter not satisfying a first preset condition, wherein the mapping mode of the LFNST transform set is an intra prediction mode mapped to the LFNST transform set;
• selecting, according to the mapping mode of the LFNST transform set, one LFNST transform kernel candidate set from a plurality of LFNST transform kernel candidate sets, determining an LFNST transform kernel used for the current block from the selected LFNST transform kernel candidate set, and setting an LFNST index and signalling the LFNST index into a video bitstream;
• and
• transforming the residual block using the LFNST transform kernel.