Method and Apparatus of Inheriting Cross-Component Model Parameters in Video Coding System

A method of coding colour pictures using coding tools including one or more cross component model related modes, the method comprising:

• receiving input data associated with a current block comprising a first-colour block and one or more second-colour blocks, wherein the input data comprises pixel data to be encoded at an encoder side or data associated with the current block to be decoded at a decoder side;
• determining a prediction candidate list comprising one or more inherited cross-component prediction candidates;
• deriving one or more target model parameter sets associated with a target inherited prediction model based on one or more inherited model parameter sets associated with the target inherited prediction model selected from the prediction candidate list, wherein when the target inherited prediction model corresponds to GLM (Gradient Linear Model), one or more gradient patterns associated with the GLM are also inherited, or when the target inherited prediction model corresponds to MMLM (Multiple Model CCLM Mode) or CCCM (Convolutional Cross-Component Model) with multi-model, a classification threshold associated with the MMLM or the CCCM with multi-mode is also inherited;
• and
• encoding or decoding at least one of said one or more second-colour blocks using prediction data comprising cross-colour prediction generated by applying the target inherited prediction model with said one or more target model parameter sets to reconstructed first-colour block.

A method of coding colour pictures using coding tools including one or more cross component models related modes, the method comprising:

• receiving input data associated with a current block comprising a first-colour block and one or more second-colour blocks, wherein the input data comprise pixel data to be encoded at an encoder side or data associated with the current block to be decoded at a decoder side;
• deriving a prediction candidate list comprising one or more inherited cross-component prediction candidates;
• checking similarity among said one or more inherited cross-component prediction candidates and one or more existing candidates in the prediction candidate list before said one or more inherited cross-component prediction candidates are inserted into the prediction candidate list;
• inserting a target inherited cross-component prediction candidate into the prediction candidate list only if a target similarity among the target inherited cross-component prediction candidate and one existing candidate in the prediction candidate list satisfies a condition;
• deriving a target predictor from the prediction candidate list;
• and
• encoding or decoding at least one of said one or more second-colour blocks using the target predictor.

An apparatus for video coding, the apparatus comprising one or more electronics or processors arranged to:

• receive input data associated with a current block comprising a first-colour block and one or more second-colour blocks, wherein the input data comprise pixel data to be encoded at an encoder side or data associated with the current block to be decoded at a decoder side;
• determine a prediction candidate list comprising one or more inherited cross-component prediction candidates;
• derive one or more target model parameter sets associated with a target inherited prediction model based on one or more inherited model parameter sets associated with the target inherited prediction model selected from the prediction candidate list, wherein when the target inherited prediction model corresponds to GLM (Gradient Linear Model), one or more gradient patterns associated with the GLM are also inherited, or when the target inherited prediction model corresponds to MMLM (Multiple Model CCLM Mode) or CCCM (Convolutional Cross-Component Model) with multi-model, a classification threshold associated with the MMLM or the CCCM with multi-mode is also inherited;
• and
• encode or decode at least one of said one or more second-colour blocks using prediction data comprising cross-colour prediction generated by applying the target inherited prediction model with said one or more target model parameter sets to reconstructed first-colour block.

An apparatus for video coding, the apparatus comprising one or more electronics or processors arranged to:

• receive input data associated with a current block comprising a first-colour block and a second-colour block, wherein the input data comprise pixel data to be encoded at an encoder side or coded data associated with the current block to be decoded at a decoder side;
• derive a prediction candidate list comprising one or more inherited cross-component prediction candidates;
• check similarity among said one or more inherited cross-component prediction candidates and one or more existing candidates in the prediction candidate list before said one or more inherited cross-component prediction candidates are inserted into the prediction candidate list;
• insert a target inherited cross-component prediction candidate into the prediction candidate list only if a target similarity among the target inherited cross-component prediction candidate and one existing candidate in the prediction candidate list satisfies a condition;
• derive a target predictor from the prediction candidate list;
• and
• encode or decode at least one of said second-colour blocks using the target predictor.