An ROI coefficient and a non-ROI coefficient in first wavelet coefficient data corresponding to a first target image are determined on the basis of mask data which is developed for the first wavelet coefficient data. The ROI coefficient in the first wavelet coefficient data and a coefficient in second wavelet coefficient data corresponding to a second target image are synthesized. Synthesized coefficient data are thereby generated. Inverse wavelet transformation is performed on the synthesized coefficient data until a decomposition level becomes a predetermined end level. Synthetic image data are thereby generated.

A method and device for decoding a point cloud using octree partitioning and a predictive tree include obtaining the point cloud. A bounding box of the point cloud is determined. Octree nodes are generated by partitioning the bounding box using octree partitioning. The predictive tree is generated for points in at least one octree node of the octree nodes. A transform is applied to the predictive tree. The points in the at least one octree node are decoded using the predictive tree.

Aspects of the disclosure include a method for point cloud coding. In the method, whether decoding of occupancy codes of nodes in a range of octree partition depths in an octree partitioning structure of a point cloud reaches a minimum octree partition depth at which parallel decoding is enabled is determined. Arithmetic coding information for decoding the occupancy codes of the nodes in the minimum octree partition depth is stored based on the decoding of the occupancy codes of the nodes in the range of octree partition depths reaching the minimum octree partition depth. The parallel decoding is performed on occupancy codes of the nodes in each of the at least one remaining octree partitions depth based on the stored arithmetic coding information. The point cloud is reconstructed based on the occupancy codes of the nodes in the range of octree partition depths in the octree partitioning structure.

A video coding mechanism is disclosed. The mechanism includes partitioning an image to create at least one coding tree unit (CTU) with at least one coding tree node. The mechanism further includes determining that the coding tree node height is twice a maximum transform unit (TU) height and the coding tree node width is twice a maximum TU width. The mechanism further includes selecting a split mode for the coding tree node based on the determination. The split mode is selected from a quad-tree split, a horizontal binary-tree split, and no split. The mechanism further includes applying the split mode to the coding tree node to create one or more coding units (CUs). The mechanism further includes encoding the CUs into a bitstream. The mechanism further includes transmitting the bitstream toward a decoder.

An image decoding method according to the present document comprises a step of deriving a corrected transform coefficient, wherein the step of deriving the corrected transform coefficient comprises the steps of: determining whether LFNST can be applied to the height and width of a divided sub-partition block when an ISP is applied to a current block; parsing a LFNST index when the LFNST can be applied; and deriving the corrected transform coefficient on the basis of the LFNST index and a LFNST matrix.

A method includes performing a conversion between a video including a video picture and a bitstream of the video according to a rule, wherein the video picture including a subpicture, a tile, and a slice, and wherein the rule specifies that, due to the subpicture including the slice that is partitioned from the tile, the conversion is performed by refraining from counting a height of the subpicture using a number of tiles of the video picture.

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes processing circuitry. The processing circuitry determines that a non-interleaved separate tree structure is used for coding different color components of coding tree units (CTUs) in a bitstream. The processing circuitry decodes a first color component of a plurality of CTUs from a first portion of the bitstream, and decodes a second color component of the plurality of CTUs from a second portion of the bitstream, the second portion is located after the first portion in the bitstream.

A visual media processing method includes performing a conversion between a current video block of a visual media data and a bitstream representation of the current video block. The bitstream representation is configured according to a format rule that specifies that a syntax element is selectively included or excluded in the bitstream representation indicative of a maximum number of merge candidates for a coding tool, thereby indicating whether the coding tool is enabled or disabled for the conversion. The maximum number of merge candidates for the coding tool is zero or a positive number.

Embodiments provide methods and devices (encoder and/or decoder) of coding a picture. A History Based Motion Vector Prediction (HMVP) list for a current Coding Tree Unit (CTU) row within a tile of a picture is initialized and a CTU of the current CTU row is processed based on the initialized HMVP list.

A method of video processing is described. The method includes determining, for a conversion between a current video block of a video and a coded representation of the video, whether a certain partitioning scheme is allowed for the current video block according to a rule that depends on a coding mode type used for representing the current video block in the coded representation and a dimension of the current video block; and performing the conversion based on the determining.