A method for deriving a value for a first syntax element, Syntax_A. The method comprises determining whether Syntax_A is present in a bitstream. The method comprises, as a result of determining that Syntax_A is not present in the bitstream, deriving the value for Syntax_A to be equal to a first value, B, if a first condition is satisfied, or deriving the value for Syntax_A to be equal to a second value, C, if a second condition is satisfied.

A video processing method includes performing a conversion between a video block of a video and a bitstream of the video according to a rule. The rule specifies whether or how usage of a secondary transform within a video unit is indicated in the bitstream. The secondary transform is applied before quantization or after de-quantization.

A video processing method includes performing a conversion between a video block of a video and a bitstream of the video according to a rule. The rule specifies whether or how usage of a secondary transform within a video unit is indicated in the bitstream. The secondary transform is applied before quantization or after de-quantization.

An image decoding method carried out by a decoding device, according to the present document, comprises the steps of: acquiring a sign data hiding enable flag; acquiring a transform skip residual coding (TSRC) enable flag on the basis of the sign data hiding enable flag; acquiring residual information for a current block, on the basis of the TSRC enable flag; deriving a residual sample of the current block, on the basis of the residual information; and generating a reconstructed picture on the basis of the residual sample, wherein the sign data hiding enable flag is a flag indicating whether sign data hiding is enabled, the TSRC enable flag is a flag indicating whether TSRC is enabled, and the TSRC enable flag is acquired on the basis of the sign data hiding enable flag having a value of zero.

An image decoding method carried out by a decoding device, according to the present document, comprises the steps of: acquiring a sign data hiding enable flag; acquiring a transform skip residual coding (TSRC) enable flag on the basis of the sign data hiding enable flag; acquiring residual information for a current block, on the basis of the TSRC enable flag; deriving a residual sample of the current block, on the basis of the residual information; and generating a reconstructed picture on the basis of the residual sample, wherein the sign data hiding enable flag is a flag indicating whether sign data hiding is enabled, the TSRC enable flag is a flag indicating whether TSRC is enabled, and the TSRC enable flag is acquired on the basis of the sign data hiding enable flag having a value of zero.

A video processing method includes performing a conversion between a video comprising a video unit and a bitstream of the video according to a rule. The rule specifies whether or how to include, in an adaptation parameter set (APS), information related to a scaling list of the video is based on a first syntax element. The first syntax element indicates whether the APS includes chroma component related syntax elements and is independent of one or more syntax elements in a sequence parameter set (SPS).

A video processing method includes performing a conversion between a video comprising a video unit and a bitstream of the video according to a rule. The rule specifies whether or how to include, in an adaptation parameter set (APS), information related to a scaling list of the video is based on a first syntax element. The first syntax element indicates whether the APS includes chroma component related syntax elements and is independent of one or more syntax elements in a sequence parameter set (SPS).

Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a video picture of a video comprising one or more slices and a bitstream of the video picture according to a rule. The rule specifies that that whether a first syntax element indicating a usage of a coding tool is present at a first level is based on a syntax flag indicating whether a syntax structure of a second level is not present at the first level, wherein the second level is higher than the first level, and wherein the second level is the video picture level or higher than the video picture level.

Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a video picture of a video comprising one or more slices and a bitstream of the video picture according to a rule. The rule specifies that that whether a first syntax element indicating a usage of a coding tool is present at a first level is based on a syntax flag indicating whether a syntax structure of a second level is not present at the first level, wherein the second level is higher than the first level, and wherein the second level is the video picture level or higher than the video picture level.

Methods and apparatuses for video coding are provided. The method includes that a decoder determines whether a disable flag is present in a picture header (PH) associated with a picture, wherein the disable flag specifies whether a coding tool is disabled in one or more slices associated with the PH. Additionally, the method includes that the decoder infers value of the disable flag according to one or more enable flags signaled in a sequence parameter set (SPS) of the picture in response to determining that the disable flag is not present in the PH, inferring, by the decoder.