Methods and apparatus for video processing are disclosed. The processing may include video encoding, video decoding, or video transcoding. One example method includes performing a conversion between a current block of a video and a bitstream of the video. The bitstream conforms to a rule that specifies that a context index offset is used for including a first sign flag of a first coefficient in the bitstream. The rule specifies that a value of the context index offset is based on whether a first coding mode is applied on the current block in the bitstream.

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.

This application provides a method for decoding an unmatched pixel performed by an electronic device. The method includes: obtaining a bit stream of a target video sequence and decoding the bit stream of the target video sequence by at least two entropy decoding methods, to obtain a binary symbol string of an unmatched pixel in a target picture block, the target picture block being obtained by dividing a target picture frame in the target video sequence; inversely binarizing the binary symbol string, to obtain a component value of the unmatched pixel; and obtaining the target picture block based on the component value of the unmatched pixel. This method can improve the flexibility of coding and facilitate equalization between the coding performance and the coding overhead of the unmatched pixel.

This application provides a method for decoding an unmatched pixel performed by an electronic device. The method includes: obtaining a bit stream of a target video sequence and decoding the bit stream of the target video sequence by at least two entropy decoding methods, to obtain a binary symbol string of an unmatched pixel in a target picture block, the target picture block being obtained by dividing a target picture frame in the target video sequence; inversely binarizing the binary symbol string, to obtain a component value of the unmatched pixel; and obtaining the target picture block based on the component value of the unmatched pixel. This method can improve the flexibility of coding and facilitate equalization between the coding performance and the coding overhead of the unmatched pixel.

Sketch copy mode may be used to code blocks comprising irregular lines, syntax redundancy may be removed from blocks with special characteristics, and/or run value coding may be simplified. The parsing dependencies in palette coding design may be removed. For example, the context modeling dependency of the syntax element palette_transpose_flag may be removed, for example, by simplifying the corresponding context model. The context modeling of the syntax element palette_mode may be removed, for example, by using run-length coding without using context. The syntax parsing dependencies and/or the syntax signaling dependencies that are related with escape color signaling may be removed. A palette table generation process may handle input screen content video with high bit depths, for example, at the encoder side.

Sketch copy mode may be used to code blocks comprising irregular lines, syntax redundancy may be removed from blocks with special characteristics, and/or run value coding may be simplified. The parsing dependencies in palette coding design may be removed. For example, the context modeling dependency of the syntax element palette_transpose_flag may be removed, for example, by simplifying the corresponding context model. The context modeling of the syntax element palette_mode may be removed, for example, by using run-length coding without using context. The syntax parsing dependencies and/or the syntax signaling dependencies that are related with escape color signaling may be removed. A palette table generation process may handle input screen content video with high bit depths, for example, at the encoder side.

An image coding method includes: an image acquisition step of acquiring a coding-target image; a feature map generation step of generating a feature map, based on the image; a contraction function generation step of performing fractal compression of the feature map and generating a contraction function; and an entropy encoding step of performing entropy encoding of the contraction function.

An image coding method includes: an image acquisition step of acquiring a coding-target image; a feature map generation step of generating a feature map, based on the image; a contraction function generation step of performing fractal compression of the feature map and generating a contraction function; and an entropy encoding step of performing entropy encoding of the contraction function.

Methods and apparatus are provided for encoding and decoding binary sets using adaptive tree selection. In one exemplary encoding method embodiment, picture data is encoded for a block in a picture; in which one of a plurality of trees structures is selected to code a binary set of data for indicating coefficient significance for the block. In another exemplary encoding method embodiment, picture data is encoded for a block in a picture, in which one or more trees are used to encode a binary set of data for indicating coefficient significance for the block, the one or more trees each having a plurality of nodes, at least one of the nodes of the one or more trees being modified responsive to at least one parameter.

Methods and apparatus are provided for encoding and decoding binary sets using adaptive tree selection. In one exemplary encoding method embodiment, picture data is encoded for a block in a picture; in which one of a plurality of trees structures is selected to code a binary set of data for indicating coefficient significance for the block. In another exemplary encoding method embodiment, picture data is encoded for a block in a picture, in which one or more trees are used to encode a binary set of data for indicating coefficient significance for the block, the one or more trees each having a plurality of nodes, at least one of the nodes of the one or more trees being modified responsive to at least one parameter.