Method and apparatus of inheriting cross-component models with cross-component information propagation in video coding system

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, and wherein the current block is coded in a non-intra mode;
• derive an inherited cross-component prediction candidate by inheriting one or more cross-component model parameters associated with an inheriting neighbouring block;
• store the inherited cross-component prediction candidate, wherein the inherited cross-component prediction candidate is used in a reconstruction process of a neighbouring block in a subsequent picture;
• encode or decode the current block using a prediction candidate list comprising the inherited cross-component prediction candidate, wherein when the inherited cross-component prediction candidate is selected from the prediction candidate list, the second-colour block is encoded or decoded by using prediction data generated by applying the inherited cross-component prediction candidate 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 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;
• determining a prediction candidate list comprising one or more inherited cross-component prediction candidates;
• inserting a default cross-component prediction candidate into the prediction candidate list when the prediction candidate list is not full, wherein the default cross-component prediction candidate is generated by using neighbouring reconstructed first-colour samples and second-colour samples of the current block to derive a cross-component model for the default cross-component prediction candidate, or by using partial model parameters or modifying model parameters associated with an earlier candidate to derive the cross-component model for the default cross-component prediction candidate;
• and
• encoding or decoding the current block using the prediction candidate list, wherein when the default cross-component prediction candidate is selected from the prediction candidate list, the second-colour block is encoded or decoded by using prediction data generated by applying the default cross-component prediction candidate 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;
• determine a prediction candidate list comprising one or more inherited cross-component prediction candidates;
• insert a default cross-component prediction candidate into the prediction candidate list when the prediction candidate list is not full, wherein the default cross-component prediction candidate is generated by using neighbouring reconstructed first-colour samples and second-colour samples of the current block to derive a cross-component model for the default cross-component prediction candidate, or by using partial model parameters or modifying model parameters associated with an earlier candidate to derive the cross-component model for the default cross-component prediction candidate;
• and
• encode or decode the current block using the prediction candidate list, wherein when the default cross-component prediction candidate is selected from the prediction candidate list, the second-colour block is encoded or decoded by using prediction data generated by applying the default cross-component prediction candidate to reconstructed first-colour block.