Image coding/decoding method, and storage medium

A picture decoding method, applicable to a decoder, the method comprising:

• decoding a bitstream to obtain a size, a coding mode, and residuals of a current block;
• when the coding mode of the current block is a Matrix-based Intra Prediction (MIP) mode, calculating a second offset based on the size of the current block, a first offset and reconstructed values of adjacent pixels corresponding to the current block, wherein the second offset is a value used to perform prediction through the MIP mode and the first offset is a constant;
• calculating a second prediction value of a pixel at a preset position in the current block by using the second offset, wherein the preset position is a particular position in the current block;
• performing filtering on the second prediction value to obtain first prediction values of all pixels in the current block;
• and
• calculating reconstructed values of the current block based on the first prediction values.

A non-transitory computer-readable storage medium having stored thereon instructions and a bitstream, wherein when the instructions are executed by a processor, the instructions implement the steps of a picture decoding method to decode the bitstream to generate a picture, the picture decoding method comprising:

• decoding a bitstream to obtain a size, a coding mode, and residuals of a current block;
• when the coding mode of the current block is a Matrix-based Intra Prediction (MIP) mode, calculating a second offset based on the size of the current block, a first offset and reconstructed values of adjacent pixels corresponding to the current block, wherein the second offset is a value used to perform prediction through the MIP mode and the first offset is a constant;
• calculating a second prediction value of a pixel at a preset position in the current block by using the second offset, wherein the preset position is a particular position in the current block;
• performing filtering on the second prediction value to obtain first prediction values of all pixels in the current block;
• and
• calculating reconstructed values of the current block based on the first prediction values.