Method and device of video coding using local illumination compensation (LIC) groups

A decoding apparatus comprising one or more processors configured to perform:

• obtaining a current picture divided into a plurality of coding units, each coding unit of the plurality of coding units belonging to a single local illumination compensation group of a plurality of local illumination compensation groups dividing the current picture and comprising at least one prediction unit and at least one transform unit, a local illumination compensation group being an area of the current picture composed of a subset of contiguous samples of the current picture
• determining at least one illumination compensation parameter representing a local illumination compensation linear model for a current coding unit of the plurality of coding units of a current local illumination group;
• and
• reconstructing the current coding unit using the determined illumination compensation parameter;
• wherein, for any current coding unit of any current local illumination compensation group of the current picture, information of the current picture used for determining the at least one illumination compensation parameter representing the local illumination compensation linear model for the current coding unit includes one or more illumination compensation parameters representing the local illumination compensation linear model associated to the current local illumination compensation group to which the current coding unit belongs or one or more reconstructed samples of at least one coding unit belonging to the current local illumination compensation group to which the current coding unit belongs.

An encoding method comprising:

• dividing a current picture into a plurality of coding units, each coding unit of the plurality of coding units belonging to a single local illumination compensation group of a plurality of local illumination compensation groups dividing the current picture and comprising at least one prediction unit and at least one transform unit, a local illumination compensation group being an area of the current picture composed of a subset of contiguous samples of the current picture;
• determining at least one illumination compensation parameter representing a local illumination compensation linear model for a current coding unit of the plurality of coding units of a current local illumination group;
• and
• encoding the current coding unit using the determined illumination compensation parameter;
• wherein, for any current coding unit of any current local illumination compensation group of the current picture, information of the current picture used for determining the at least one illumination compensation parameter representing the local illumination compensation linear model for the current coding unit includes one or more illumination compensation parameters representing the local illumination compensation linear model associated to the current local illumination compensation group to which the current coding unit belongs or one or more reconstructed samples of at least one coding unit belonging to the current local illumination compensation group to which the current coding unit belongs.

An encoding apparatus comprising one or more processors configured to perform:

• dividing a current picture in a plurality of coding units, each coding unit of the plurality of coding units belonging to a single local illumination compensation group of a plurality of local illumination compensation groups dividing the current picture and comprising at least one prediction unit and at least one transform unit, a local illumination compensation group being an area of the current picture composed of a subset of contiguous samples of the current picture;
• determining at least one illumination compensation parameter representing a local illumination compensation linear model for a current coding unit of the plurality of coding units of a current local illumination group;
• and
• encoding the current coding unit using the determined illumination compensation parameter;
• wherein, for any current coding unit of any current local illumination compensation group of the current picture, information of the current picture used for determining the at least one illumination compensation parameter representing the local illumination compensation linear model for the current coding unit includes one or more illumination compensation parameters representing the local illumination compensation linear model associated to the current local illumination compensation group to which the current coding unit belongs or one or more reconstructed samples of at least one coding unit belonging to the current local illumination compensation group to which the current coding unit belongs.