A three-dimensional data encoding method includes: shifting point cloud data indicating three-dimensional positions in a three-dimensional space by a first shift amount; dividing the point cloud data into pieces of sub point cloud data; shifting each of the pieces of sub point cloud data by a second shift amount based on a position of one of the subspaces that includes the sub point cloud data, the pieces of sub point cloud data being included in the point cloud data shifted by the first shift amount; and encoding the pieces of sub point cloud data shifted, to generate a bitstream. The bitstream includes first shift information for calculating the first shift amount, and pieces of second shift information each for calculating a corresponding one of second shift amounts by which the pieces of sub point cloud data are shifted and each of which is the second shift amount.

The disclosure proposes a decoder for decoding coefficients of blocks of a video sequence from a bitstream. The decoder comprises a scan pattern list module for providing one or more pre-defined scan orders, a scan order generator for generating one or more scan orders, a scan order selector for selecting a scan order for each block from the pre-defined and generated scan orders on the basis of scan order information contained in the bitstream, a decoding module for decoding one or more coefficient vectors of each block from the bitstream, a deserializer for inverse scanning, for each block, the one or more coefficient vectors of that block according to the scan order selected for that block so as to obtain a coefficient matrix. The scan order generator generates the one or more scan orders depending on one or more previously obtained coefficient matrices of blocks of the video sequence.

The disclosure proposes a decoder for decoding coefficients of blocks of a video sequence from a bitstream. The decoder comprises a scan pattern list module for providing one or more pre-defined scan orders, a scan order generator for generating one or more scan orders, a scan order selector for selecting a scan order for each block from the pre-defined and generated scan orders on the basis of scan order information contained in the bitstream, a decoding module for decoding one or more coefficient vectors of each block from the bitstream, a deserializer for inverse scanning, for each block, the one or more coefficient vectors of that block according to the scan order selected for that block so as to obtain a coefficient matrix. The scan order generator generates the one or more scan orders depending on one or more previously obtained coefficient matrices of blocks of the video sequence.

Described is picture segmentation through columns and slices in video encoding and decoding. A video picture is divided into a plurality of columns, each column covering only a part of the video picture in a horizontal dimension. All coded tree blocks (“CTBs”) belonging to a slice may belong to one or more columns. The columns may be used to break the same or different prediction or in-loop filtering mechanisms of the video coding, and the CTB scan order used for encoding and/or decoding may be local to a column. Column widths may be indicated in a parameter set and/or may be adjusted at the slice level. At the decoder, column width may be parsed from the bitstream, and slice decoding may occur in one or more columns.

Described is picture segmentation through columns and slices in video encoding and decoding. A video picture is divided into a plurality of columns, each column covering only a part of the video picture in a horizontal dimension. All coded tree blocks (“CTBs”) belonging to a slice may belong to one or more columns. The columns may be used to break the same or different prediction or in-loop filtering mechanisms of the video coding, and the CTB scan order used for encoding and/or decoding may be local to a column. Column widths may be indicated in a parameter set and/or may be adjusted at the slice level. At the decoder, column width may be parsed from the bitstream, and slice decoding may occur in one or more columns.

A method, computer program, and computer system is provided for aligning across layers in a coded video stream. A video bitstream having multiple layers is decoded. One or more subpicture regions are identified from among the multiple layers of the decoded video bitstream, the subpicture regions including a background region and one or more foreground subpicture regions. An enhanced subpicture is decoded and displayed based on a determination that a foreground subpicture region is selected. The background region is decoded and displayed based on a determination that a foreground subpicture region was not selected.

A method performed by a decoder for decoding a bitstream comprising a picture parameter set, PPS, and a first set of slices. The method includes obtaining the picture parameter set. The method also includes decoding a syntax element included in the picture parameter set to obtain an indicator value. The decoder is configured such that if the indicator value is set to a first value then the decoder determines that a picture header included in the bitstream comprises a parameter value corresponding to a particular parameter, otherwise the decoder determines that each slice included in the first set of slices comprises a parameter value corresponding to the particular parameter. If the picture header comprises the parameter value corresponding to the particular parameter, then this parameter value is used to decode slice data of each slice included in the first set of slices.

A method performed by a decoder for decoding a bitstream comprising a picture parameter set, PPS, and a first set of slices. The method includes obtaining the picture parameter set. The method also includes decoding a syntax element included in the picture parameter set to obtain an indicator value. The decoder is configured such that if the indicator value is set to a first value then the decoder determines that a picture header included in the bitstream comprises a parameter value corresponding to a particular parameter, otherwise the decoder determines that each slice included in the first set of slices comprises a parameter value corresponding to the particular parameter. If the picture header comprises the parameter value corresponding to the particular parameter, then this parameter value is used to decode slice data of each slice included in the first set of slices.

According to an embodiment of the present document, a method for increasing the accuracy of in-loop filtering is proposed. In an example, the filtering accuracy of chroma blocks can be improved on the basis of luma blocks by performing a cross component adaptive loop filtering process.

A system for decoding a video bitstream includes receiving a reference picture set associated with a frame including a set of reference picture identifiers. The reference picture set identifies one or more reference pictures to be used for inter-prediction of the frame based upon its associated least significant bits of a picture order count based upon the reference picture identifiers. The one or more reference pictures is a second or greater previous frame to the frame having the matching reference picture identifier.