A video processing method includes checking, during a conversion from a coded representation of a current video block to the current video block, a position of a last non-zero coefficient of the current video block, wherein the position is relative to a top-left position of the current video block; and performing a determination, based on the position, whether or not to parse a syntax element which signals a transform information in the coded representation.

Devices, systems and methods for digital video coding, which includes: determining whether a sample is located at sub-block transform boundaries in case that a sub-block transform is applied; applying deblocking filter process if it is determined that the sample is located at sub-block transform boundaries; and performing a conversion between the video and a bitstream representation of the video.

An image encoding apparatus comprises a selector configured to select a prediction operation, for prediction of samples of a current region of a current image with respect to one or more of a group of reference samples, from a set of candidate prediction operations, at least some of which define, as an intra-image prediction operation, a prediction direction between a current sample to be predicted and a group of reference samples in the same image; and an intra-image predictor configured to derive predicted samples of a current image region from reference samples of the same image in response to selection, by the selector, of an intra-image prediction operation for the current image region; in which: the current region comprises at least a subset of a current coding tree unit (CTU) in an array of CTUs; the group of references samples is disposed, with respect to the current image region at one or more predetermined sides of the current image region; and the selector is configured to inhibit the selection of a prediction operation for the current region, for which at least some of the reference samples at one or more of the predetermined sides of the current image region are disposed in a CTU other than the current CTU.

An image encoding apparatus comprises a selector configured to select a prediction operation, for prediction of samples of a current region of a current image with respect to one or more of a group of reference samples, from a set of candidate prediction operations, at least some of which define, as an intra-image prediction operation, a prediction direction between a current sample to be predicted and a group of reference samples in the same image; and an intra-image predictor configured to derive predicted samples of a current image region from reference samples of the same image in response to selection, by the selector, of an intra-image prediction operation for the current image region; in which: the current region comprises at least a subset of a current coding tree unit (CTU) in an array of CTUs; the group of references samples is disposed, with respect to the current image region at one or more predetermined sides of the current image region; and the selector is configured to inhibit the selection of a prediction operation for the current region, for which at least some of the reference samples at one or more of the predetermined sides of the current image region are disposed in a CTU other than the current CTU.

A method of video processing includes determining a classification of samples of a block in a video picture of a video according to a rule, wherein the video picture is divided into multiple regions, and wherein the rule disallows use of neighboring samples of a current sample across one or more boundaries of the multiple regions for the classification. The one or more boundaries of the multiple regions comprises a virtual boundary for an adaptive loop filtering (ALF) process. The method also includes performing a conversion between the block and a bitstream representation of the video by selectively applying the ALF process according to the classification.

A method of video processing includes determining a classification of samples of a block in a video picture of a video according to a rule, wherein the video picture is divided into multiple regions, and wherein the rule disallows use of neighboring samples of a current sample across one or more boundaries of the multiple regions for the classification. The one or more boundaries of the multiple regions comprises a virtual boundary for an adaptive loop filtering (ALF) process. The method also includes performing a conversion between the block and a bitstream representation of the video by selectively applying the ALF process according to the classification.

A three-dimensional data encoding method includes encoding information of a current node included in an N-ary tree structure of three-dimensional points included in three-dimensional data, where N is an integer greater than or equal to 2. In the encoding, first information is encoded, the first information indicating a range for one or more referable neighboring nodes among neighboring nodes spatially neighboring the current node, and the current node is encoded with reference to a neighboring node within the range.

A three-dimensional data encoding method includes encoding information of a current node included in an N-ary tree structure of three-dimensional points included in three-dimensional data, where N is an integer greater than or equal to 2. In the encoding, first information is encoded, the first information indicating a range for one or more referable neighboring nodes among neighboring nodes spatially neighboring the current node, and the current node is encoded with reference to a neighboring node within the range.

A method of decoding coding blocks of a coding tree unit in an image. The method comprises obtaining the coding tree unit in the image from a bitstream, the coding tree unit having chroma channels and a luma channel; and determining luma split options for the luma channel of the coding tree unit according to dimensions of a region of the coding tree unit. The method also comprises determining chroma split options for the chroma channels of the coding tree unit according to dimensions of a region of the coding tree unit, the chroma split options being different to the luma split options, the allowable chroma split options resulting in chroma intra predicted blocks with a minimum size of 16 samples; and decoding the coding blocks by determining flags from the bitstream to select one of the determined luma split options and one of the determined chroma split options.

A method of decoding coding blocks of a coding tree unit in an image. The method comprises obtaining the coding tree unit in the image from a bitstream, the coding tree unit having chroma channels and a luma channel; and determining luma split options for the luma channel of the coding tree unit according to dimensions of a region of the coding tree unit. The method also comprises determining chroma split options for the chroma channels of the coding tree unit according to dimensions of a region of the coding tree unit, the chroma split options being different to the luma split options, the allowable chroma split options resulting in chroma intra predicted blocks with a minimum size of 16 samples; and decoding the coding blocks by determining flags from the bitstream to select one of the determined luma split options and one of the determined chroma split options.