Intra-frame prediction and decoding methods and apparatuses for image signal

An apparatus for chroma component prediction, comprising:

• a memory configured to store instructions;
• and
• a processor coupled to the memory and configured to execute the instructions, which cause the processor to be configured to:
• obtain reference samples of a current block, wherein the reference samples comprise a luma reference sample array and a chroma reference sample array;
• obtain a correlation parameter based on the luma reference sample array and the chroma reference sample array;
• and
• calculate a prediction value of a chroma component of the current block based on a luma component of the current block and the correlation parameter,
• wherein the reference samples consist of samples on a top side of the current block and on a top right of the current block or the reference samples comprise samples on a left side of the current block and on a bottom left of the current block.

A computer program product comprising computer-executable instructions for storage on a non-transitory computer-readable medium that, when executed by a processor of a device, cause the device to:

• obtain reference samples of a current block, wherein the reference samples comprise a luma reference sample array and a chroma reference sample array;
• obtain a correlation parameter based on the luma reference sample array and the chroma reference sample array;
• and
• calculate a prediction value of a chroma component of the current block based on a luma component of the current block and the correlation parameter,
• wherein the reference samples consist of samples on a top side of the current block and on a top right of the current block or the reference samples comprise samples on a left side of the current block and on a bottom left of the current block.