Colour component prediction method, encoder, decoder and storage medium

A method for predicting colour components, which is applied to a decoder, the method comprising:

• determining adjacent reference samples of a current block in a picture;
• constructing a subset of adjacent reference samples according to the adjacent reference samples, wherein the subset of adjacent reference samples contains a part of the adjacent reference samples;
• and
• calculating model parameters of a prediction model according to the subset of adjacent reference samples, wherein the prediction model is configured to perform cross-component prediction of colour components to be predicted,
• wherein constructing the subset of adjacent reference samples according to the adjacent reference samples comprises:
• determining candidate positions of candidate samples based on at least one edge of the current block;
• and determining reference samples corresponding to the candidate positions from the adjacent reference samples, and forming the subset of adjacent reference samples with the determined reference samples;
• wherein determining the candidate positions of the candidate samples based on the at least one edge of the current block comprises:
• calculating a first sampling interval according to a preset number of candidate samples and a length of the at least one edge of the current block;
• and determining a reference point from the at least one edge of the current block, and determining the candidate positions according to the first sampling interval.

A computer-readable storage medium, having a computer program and a bitstream stored thereon, wherein the computer program, when executed by a processor, enables the processor to perform the following operations to generate the bitstream:

• determining adjacent reference samples of a current block in a picture;
• constructing a subset of adjacent reference samples according to the adjacent reference samples, wherein the subset of adjacent reference samples contains a part of the adjacent reference samples;
• and
• calculating model parameters of a prediction model according to the subset of adjacent reference samples, wherein the prediction model is configured to perform cross-component prediction of colour components to be predicted,
• wherein constructing the subset of adjacent reference samples according to the adjacent reference samples comprises:
• determining candidate positions of candidate samples based on at least one edge of the current block;
• and determining reference samples corresponding to the candidate positions from the adjacent reference samples, and forming the subset of adjacent reference samples with the determined reference samples;
• wherein determining the candidate positions of the candidate samples based on the at least one edge of the current block comprises:
• calculating a first sampling interval according to a preset number of candidate samples and a length of the at least one edge of the current block;
• and determining a reference point from the at least one edge of the current block, and determining the candidate positions according to the first sampling interval.