Method and apparatus for cross-component linear model prediction for chroma coding

A method of encoding by an encoder, comprising:

• in response to a co-located luma block being coded using intra template matching (intraTMP), intra block copy (IBC), or inter-prediction mode, determining, by a processor, a current chroma block is eligible for prediction using a block vector or motion-vector guided (B-MVG)-cross-component linear model (CCLM) (B-MVG-CCLM) mode;
• encoding, by the processor, a fused B-MVG-CCLM (FB-MVG-CCLM) flag;
• and
• in response to the FB-MVG-CCLM flag indicating an FB-MVG-CCLM mode is selected for the current chroma block, generating, by the processor, an FB-MVG-CCLM mode prediction for the current chroma block.

A non-transitory computer-readable medium storing a bitstream and instructions, wherein the instructions, which when executed by a processor of an encoder, cause the processor of the encoder to perform the following steps to generate the bitstream:

• in response to a co-located luma block being coded using intra template matching (intraTMP), intra block copy (IBC), or inter-prediction mode, determining a current chroma block is eligible for prediction using a block vector or motion-vector guided (B-MVG)-cross-component linear model (CCLM) (B-MVG-CCLM) mode;
• encoding a fused B-MVG-CCLM (FB-MVG-CCLM) flag;
• and
• in response to the FB-MVG-CCLM flag indicating an FB-MVG-CCLM mode is selected for the current chroma block, generating an FB-MVG-CCLM mode prediction for the current chroma block.