Patent ID: 11930219
Assignee: BEIJING BYTEDANCE NETWORK TECHNOLOGY CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of processing video data, comprising:
performing a conversion between a video comprising a video unit and a bitstream of the video according to a rule,
wherein the rule specifies that a first bitstream constraint under semantics of a first syntax element in a picture header (PH) or a slice header (SH) is applied to constrain a value of a second syntax element of an adaptation parameter set (APS) network abstraction layer (NAL) unit having a scaling APS type and having a second APS identifier equal to a value of the first syntax element based on a chroma format,
wherein the value of the first syntax element indicates a first APS identifier of an APS referred by the PH or the SH, and the value of the second syntax element indicates whether the APS NAL unit is allowed to include chroma related syntax elements,
wherein the rule further specifies that whether one or more fourth syntax elements for chroma residual scaling of a luma mapping with a chroma scaling tool are included in the APS is dependent on a fifth syntax element present in a syntax structure of the APS that is used to control a presence of the one or more fourth syntax elements,
wherein the rule further specifies that when the chroma format is 4:0:0, the fifth syntax element is equal to a second certain value that indicates that the one or more fourth syntax elements are excluded from the APS, and
wherein the one or more fourth syntax elements include a sixth syntax element that indicates an absolute codeword value of a variable related to the luma mapping with the chroma scaling tool and a seventh syntax element that indicates a sign of the variable.