Method, apparatus, and system for sampling-based dynamic mesh compression are provided. The process may include determining one or more sample positions associated with an input mesh based on one or more sampling rates, and an occupancy status associated respectively with each of the one or more sample positions indicating whether each of the one or more sample positions is within boundaries of one or more polygons defined by the input mesh is determined. The process may include generating a sample-based occupancy map based on the occupancy status associated respectively with each of the one or more sample positions.

Method, apparatus, and system for sampling-based dynamic mesh compression are provided. The process may include determining one or more sample positions associated with an input mesh based on one or more sampling rates, and an occupancy status associated respectively with each of the one or more sample positions indicating whether each of the one or more sample positions is within boundaries of one or more polygons defined by the input mesh is determined. The process may include generating a sample-based occupancy map based on the occupancy status associated respectively with each of the one or more sample positions.

Flag information associated with the current block is obtained in coded information, which indicates whether the current block is intra predicted based at least in part on an intra mode derivation. In response to the flag information being true, a plurality of candidate intra modes is determined based on neighboring samples of the current block. A first intra mode of the current block is determined based on a first syntax element that is included in the coded information. The first syntax element indicates the first intra mode of the current block from a most probable mode (MPM) list and a MPM remainder. A second intra mode of the current block is determined based on the first intra mode and the plurality of candidate intra modes. The current block is reconstructed based on the first intra mode and the second intra mode.

Flag information associated with the current block is obtained in coded information, which indicates whether the current block is intra predicted based at least in part on an intra mode derivation. In response to the flag information being true, a plurality of candidate intra modes is determined based on neighboring samples of the current block. A first intra mode of the current block is determined based on a first syntax element that is included in the coded information. The first syntax element indicates the first intra mode of the current block from a most probable mode (MPM) list and a MPM remainder. A second intra mode of the current block is determined based on the first intra mode and the plurality of candidate intra modes. The current block is reconstructed based on the first intra mode and the second intra mode.

An image decoding method performed by a decoding device according to the present disclosure comprises the steps of: obtaining prediction-related information and indication information comprising a first flag which indicates whether or not a sample adaptive offset (SAO) process to be applied to a current block is applied at a picture level or a slice level; parsing information related to the SAO process from a picture header or a slice header on the basis of the first flag; generating prediction samples for the current block on the basis of the prediction-related information; generating reconstructed samples for the current block on the basis of the prediction samples; and performing the SAO process for the reconstructed samples on the basis of the information related to the SAO process.

Devices, systems and methods related to digital video coding, and specifically, to signaling of slice types in video picture headers are described. One example method of video processing includes performing a conversion between a video including one or more video pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that for a video picture of the one or more video pictures having all slices coded as I slices, P slice and B slice related syntax elements are omitted from a picture header for the video picture.

Devices, systems and methods related to digital video coding, and specifically, to signaling of slice types in video picture headers are described. One example method of video processing includes performing a conversion between a video including one or more video pictures including one or more slices and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that for a video picture of the one or more video pictures having all slices coded as I slices, P slice and B slice related syntax elements are omitted from a picture header for the video picture.

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus may comprise determining prediction mode characteristic information based on a color format of a current block, determining a prediction mode type of a lower-layer block split from the current block based on the prediction mode characteristic information, obtaining the lower-layer block by splitting the current block based on the prediction mode type of the lower-layer block, and decoding the lower-layer block based on the prediction mode type of the lower-layer block. The prediction mode type of the lower-layer block comprises a first prediction mode type specifying that both an intra prediction mode and an inter prediction mode are available, a second prediction mode type specifying that only the intra prediction mode is available and a third prediction mode type specifying that only the inter prediction mode is available. Based on a first condition for the current block being satisfied, the prediction mode characteristic information has a first value, and the first condition comprises a case where a color format of the current block is a monochrome format or a 4:4:4 format. Based on the first condition for the current block being not satisfied, the prediction mode characteristic information has a second value or a third value based on at least one of a color format, split mode or size of the current block.

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus may comprise determining prediction mode characteristic information based on a color format of a current block, determining a prediction mode type of a lower-layer block split from the current block based on the prediction mode characteristic information, obtaining the lower-layer block by splitting the current block based on the prediction mode type of the lower-layer block, and decoding the lower-layer block based on the prediction mode type of the lower-layer block. The prediction mode type of the lower-layer block comprises a first prediction mode type specifying that both an intra prediction mode and an inter prediction mode are available, a second prediction mode type specifying that only the intra prediction mode is available and a third prediction mode type specifying that only the inter prediction mode is available. Based on a first condition for the current block being satisfied, the prediction mode characteristic information has a first value, and the first condition comprises a case where a color format of the current block is a monochrome format or a 4:4:4 format. Based on the first condition for the current block being not satisfied, the prediction mode characteristic information has a second value or a third value based on at least one of a color format, split mode or size of the current block.

A method for intra prediction of a video block, comprising: padding of luminance reference samples rows for a chroma component of a current block vertically aligned with a largest coding unit (LCU) boundary; applying a filter F to reconstructed luma samples of a luma component of the current block and to luma samples in selected position neighboring to the current block, to obtain filtered reconstructed luma samples, wherein a shape of the F is same for blocks in the LCU; obtaining linear model coefficients, based on the filtered reconstructed luma samples; and performing cross-component prediction based on the obtained linear model coefficients and the filtered reconstructed luma samples of the current block, to obtain a prediction value of the chroma component of the current block.