Weighted prediction parameter coding

A device for coding video data, the device comprising a video coder configured to:

• code weighted prediction parameters for a first list, wherein the first list includes reference pictures used for inter-predicting one or more blocks within a current picture;
• determine weighted prediction parameters for a second list based on the weighted prediction parameters for the first list, wherein the second list includes reference pictures used for inter-predicting one or more blocks within the current picture;
• and
• inter-predict a block in the current picture based at least on one or more of the weighted prediction parameters that are coded and the determined weighted prediction parameters.

A computer-readable storage medium having instructions stored thereon that when executed cause one or more processors of a device for video coding to:

• code weighted prediction parameters for a first list, wherein the first list includes reference pictures used for inter-predicting one or more blocks within a current picture;
• determine weighted prediction parameters for a second list based on the weighted prediction parameters for the first list, wherein the second list includes reference pictures used for inter-predicting one or more blocks within the current picture;
• and
• inter-predict a block in the current picture based at least on one or more of the weighted prediction parameters that are coded and the determined weighted prediction parameters.

A device for coding video data, the device comprising:

• means for coding weighted prediction parameters for a first list, wherein the first list includes reference pictures used for inter-predicting one or more blocks within a current picture;
• means for determining weighted prediction parameters for a second list based on the weighted prediction parameters for the first list, wherein the second list includes reference pictures used for inter-predicting one or more blocks within the current picture;
• and
• means for inter-predicting a block in the current picture based at least on one or more of the weighted prediction parameters that are coded and the determined weighted prediction parameters.

A method for coding video data, the method comprising:

• constructing a first reference picture list;
• constructing a second reference picture list;
• coding at least a first syntax element that indicates whether the first reference picture list is identical to the second reference picture list;
• when the first syntax element indicates that the first reference picture list is identical to the second reference picture list, coding weighted prediction parameters for reference pictures identified in the first reference picture list, and not coding weighted prediction parameters for reference pictures identified in the second reference picture list;
• and
• when the first syntax element indicates that the first reference picture list is identical to the second reference picture list, predicting a video block from at least one reference picture identified in the first reference picture list and based on a weighted prediction parameter for that reference picture.

A method for coding video data, the method comprising:

• coding at least a first syntax element that indicates whether a first N elements of a first reference picture list and a second reference picture list are the same;
• when the first N elements are the same, coding information that indicates a size of the first reference picture list and a size of the second reference picture list;
• when the size of the first reference picture list is greater than the size of the second reference picture list:
• constructing the first reference picture list;
• and
• deriving the second reference picture list from the first reference picture list;
• and
• when the size of the second reference picture list is greater than the size of the first reference picture list:
• constructing the second reference picture list;
• and
• deriving the first reference picture list from the second reference picture list.