Decoding method, encoding method, and storage medium

An encoding method, applicable to an encoder and comprising:

• obtaining a residual block of a current block;
• performing third transform on the residual block of the current block, to obtain third transform coefficients of the current block;
• in response to a prediction mode for predicting the current block comprising an optimal matrix based intra prediction (MIP) mode and an intra prediction mode derived from a decoder side intra mode derivation (DIMD) mode for reconstructed samples in a first template region adjacent to the current block, determining a first intra prediction mode to be the intra prediction mode derived from the DIMD mode for the reconstructed samples in the first template region;
• performing fourth transform on the third transform coefficients based on a transform set corresponding to the first intra prediction mode, to obtain fourth transform coefficients of the current block;
• and
• encoding the fourth transform coefficients.

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:

• obtaining a residual block of a current block;
• performing third transform on the residual block of the current block, to obtain third transform coefficients of the current block;
• in response to a prediction mode for predicting the current block comprising an optimal matrix based intra prediction (MIP) mode and an intra prediction mode derived from a decoder side intra mode derivation (DIMD) mode for reconstructed samples in a first template region adjacent to the current block, determining a first intra prediction mode to be the intra prediction mode derived from the DIMD mode for the reconstructed samples in the first template region;
• performing fourth transform on the third transform coefficients based on a transform set corresponding to the first intra prediction mode, to obtain fourth transform coefficients of the current block;
• and
• encoding the fourth transform coefficients.