Signaling of prediction weights in general constraint information of a bitstream

An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:

• perform a conversion between a current slice of a current picture of a video and a bitstream of the video,
• wherein the bitstream conforms to a format rule,
• wherein the format rule specifies that when a value of a first syntax element indicates that weighted prediction information is allowed to be present in a picture header syntax structure and is not present in slice headers referring to a picture parameter set (PPS), values of a plurality of flags indicative of whether prediction weighting factors are included in the bitstream are inferred based on a slice type of the current slice and a value of a second syntax element included in the PPS referred to by the current picture,
• wherein the second syntax element indicates whether weighted prediction is enabled for P slices of pictures referring to the PPS, or the second syntax element indicates whether explicit weighted prediction is enabled for B slices of pictures referring to the PPS, and
• wherein when the value of the first syntax element indicates that the weighted prediction information is allowed to be present in the picture header syntax structure and is not present in the slice headers referring to the PPS, weighted prediction is applied for P slices and/or B slices of the current picture.

A non-transitory computer-readable storage medium storing instructions that cause a processor to:

• perform a conversion between a current slice of a current picture of a video and a bitstream of the video,
• wherein the bitstream conforms to a format rule,
• wherein the format rule specifies that when a value of a first syntax element indicates that weighted prediction information is allowed to be present in a picture header syntax structure and is not present in slice headers referring to a picture parameter set (PPS), values of a plurality of flags indicative of whether prediction weighting factors are included in the bitstream are inferred based on a slice type of the current slice and a value of a second syntax element included in the PPS referred to by the current picture,
• wherein the second syntax element indicates whether weighted prediction is enabled for P slices of pictures referring to the PPS, or the second syntax element indicates whether explicit weighted prediction is enabled for B slices of pictures referring to the PPS, and
• wherein when the value of the first syntax element indicates that the weighted prediction information is allowed to be present in the picture header syntax structure and is not present in the slice headers referring to the PPS, weighted prediction is applied for P slices and/or B slices of the current picture.

A method of storing a bitstream of a video, comprising:

• generating the bitstream of the video comprising a current picture, wherein the current picture comprises a current slice;
• and
• storing the bitstream in a non-transitory computer-readable recording medium,
• wherein the generated bitstream conforms to a format rule,
• wherein the format rule specifies that when a value of a first syntax element indicates that weighted prediction information is allowed to be present in a picture header syntax structure and is not present in slice headers referring to a picture parameter set (PPS), values of a plurality of flags indicative of whether prediction weighting factors are included in the bitstream are inferred based on a slice type of the current slice and a value of a second syntax element included in the PPS referred to by the current picture,
• wherein the second syntax element indicates whether weighted prediction is enabled for P slices of pictures referring to the PPS, or the second syntax element indicates whether explicit weighted prediction is enabled for B slices of pictures referring to the PPS, and
• wherein when the value of the first syntax element indicates that the weighted prediction information is allowed to be present in the picture header syntax structure and is not present in the slice headers referring to the PPS, weighted prediction is applied for P slices and/or B slices of the current picture.