Abstract: A three-dimensional data encoding method includes: generating a bitstream by encoding subspaces included in a current space in which three-dimensional points are included. The bitstream includes encoded data respectively corresponding to the subspaces. In the generating of the bitstream, a list of information about the subspaces is stored in first control information included in the bitstream. The subspaces are respectively associated with identifiers assigned to the subspaces, and the first control information is common to the encoded data. Each of the identifiers assigned to the subspaces respectively corresponding to the encoded data is stored in a header of a corresponding one of the encoded data.

Abstract: A three-dimensional data encoding method includes: obtaining three-dimensional points; generating a data unit including one or more prediction trees, using the three-dimensional points; and generating a bitstream including the data unit and control information. The control information includes tree information about the one or more prediction trees, and the tree information includes number information indicating a total number of prediction trees included in the data unit.

Abstract: 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.

Abstract: A three-dimensional data encoding method includes: dividing three-dimensional points included in three-dimensional data into three-dimensional point sub-clouds including a first three-dimensional point sub-cloud and a second three-dimensional point sub-cloud; appending first information indicating a space of the first three-dimensional point sub-cloud to a header of the first three-dimensional point sub-cloud, and appending second information indicating a space of the second three-dimensional point sub-cloud to a header of the second three-dimensional point sub-cloud; and encoding the first three-dimensional point sub-cloud and the second three-dimensional point sub-cloud so that the first three-dimensional point sub-cloud and the second three-dimensional point sub-cloud are decodable independently of each other.

Abstract: A three-dimensional data encoding method includes: quantizing geometry information of each of three-dimensional points, using a first quantization parameter; quantizing a first luminance using a second quantization parameter and quantizing a first chrominance using a third quantization parameter, the first luminance and the first chrominance indicating a first color among attribute information of each of the three dimensional points; and generating a bitstream including the geometry information quantized, the first luminance quantized, the first chrominance quantized, the first quantization parameter, the second quantization parameter, and a first difference between the second quantization parameter and the third quantization parameter.

Abstract: A three-dimensional data encoding method includes: encoding a first flag indicating whether a node having a parent node different from a parent node of a current node is to be referred to in encoding of the current node included in an n-ary tree structure of three-dimensional points included in three-dimensional data; selecting a coding table from N coding tables according to occupancy states of neighboring nodes of the current node, and performing arithmetic encoding on information of the current node using the coding table selected, when the first flag indicates that the node is to be referred to; and selecting a coding table from M coding tables according to the occupancy states of the neighboring nodes of the current node, and performing arithmetic encoding on information of the current node using the coding table selected, when the first flag indicates that the node is not to be referred to.

Abstract: 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.

Abstract: A three-dimensional data encoding method includes: obtaining a data unit including three-dimensional points; generating one or more prediction trees using the three-dimensional points included in the data unit; performing predictive encoding on position information items of one or more three-dimensional points among the three-dimensional points, using a prediction tree including the one or more three-dimensional points; and generating a bitstream including encoded data resulting from the predictive encoding. In the performing, (i) a prediction value in a specific prediction mode is obtained, and (ii) one or more prediction residuals are calculated for each of the one or more three-dimensional points, the one or more prediction residuals each being a difference between a position information item of the three-dimensional point and the prediction value.

Abstract: A three-dimensional data encoding method includes: obtaining first three-dimensional points; encoding the first three-dimensional points using one of a plurality of encoding schemes; and generating a bitstream including first encoded data and a first identification information item, the first encoded data being obtained by encoding the first three-dimensional points. The encoding of the first three-dimensional points includes: determining whether a context used for encoding is continuously used; and encoding the first three-dimensional points using a context corresponding to a determination result in the determining, the context being included in contexts used in an encoding scheme used for the encoding and included in the encoding schemes, and the first identification information item includes the determination result in the determining.

Abstract: A three-dimensional data encoding method includes: quantizing geometry information of each of three-dimensional points, using a first quantization parameter; quantizing a first luminance using a second quantization parameter and quantizing a first chrominance using a third quantization parameter, the first luminance and the first chrominance indicating a first color among attribute information of each of the three dimensional points; and generating a bitstream including the geometry information quantized, the first luminance quantized, the first chrominance quantized, the first quantization parameter, the second quantization parameter, and a first difference between the second quantization parameter and the third quantization parameter.

Abstract: A three-dimensional data encoding method includes: generating a bitmap indicating which of pieces of three-dimensional data a three-dimensional point belongs to, the three-dimensional point being included in a unit space; generating a conversion code using a look-up table and the bitmap generated; and generating encoded data including duplicated point information indicating a total number of three-dimensional points included in the unit space, and conversion code information indicating the conversion code. The generating of the conversion code includes: generating the conversion code from the bitmap when the total number of the three-dimensional points included in the unit space is less than or equal to a predetermined threshold value; and generating the conversion code from an inverted bitmap when the total number of the three-dimensional points included in the unit space is greater than the predetermined threshold value, the inverted bitmap being obtained by inverting 0 and 1 included in the bitmap.

Abstract: A three-dimensional data encoding method includes: determining whether to encode each of data units using both or one of an N-ary tree and a prediction tree, each of the data units including three-dimensional points, N being an integer greater than or equal to 2; and generating a bitstream by encoding position information items of the three-dimensional points included in each of the data units, using the both or one of the N-ary tree and the prediction tree determined.

Abstract: A three-dimensional data encoding method includes: generating a first predicted value for an item of position information of a first three-dimensional point included in point cloud data, using an item of position information of a reference three-dimensional point included in the point cloud data and angle information; calculating a first difference value between the item of position information of the first three-dimensional point and the first predicted value; and generating a bitstream including the first difference value and the angle information.

Abstract: A three-dimensional data encoding method includes: generating a bitmap for combined three-dimensional data that is a combination of pieces of three-dimensional data, the bitmap indicating which of the pieces of three-dimensional data a three-dimensional point belongs to, the three-dimensional point being a three-dimensional point of the combined three-dimensional data and included in a unit space; generating a conversion code using the bitmap; and generating encoded data including duplicated point information indicating a total number of three-dimensional points included in the unit space, and conversion code information indicating the conversion code. Each of values of the bitmap corresponds to a combination of the conversion code and the total number of the three-dimensional points included in the unit space.

Abstract: A three-dimensional data encoding method includes: determining a first maximum bit count for encoded data obtained after encoding at least one of (i) a divisional data unit obtained when point cloud data indicating a three-dimensional point cloud is divided or (ii) a point cloud data unit of the point cloud data before the dividing; and generating a bitstream by encoding (i) items of divisional data obtained by dividing the point cloud data or (ii) the point cloud data before the dividing, to satisfy the first maximum bit count determined. The bitstream includes first bit count information indicating the first maximum bit count.

Abstract: A three-dimensional data decoding method includes: obtaining three-dimensional space information including encoded three-dimensional points; calculating an angle formed by a line segment connecting a predetermined position in the three-dimensional space information and a first base point and a line segment connecting the first base point and a second base point different from the first base point; determining whether the angle calculated satisfies a predetermined condition; and decoding the encoded three-dimensional points included in the three-dimensional space information when the angle calculated is determined to satisfy the predetermined condition, and not decoding the encoded three-dimensional points included in the three-dimensional space information when the angle calculated is determined not to satisfy the predetermined condition.

Abstract: A three-dimensional data encoding method includes: encoding three-dimensional points each located in any one of a plurality of regions, on a per region basis, to generate encoded three-dimensional points; generating connectivity information generated based on a relationship between a first region among the plurality of regions and second regions aside from the first region among the plurality of regions, the connectivity information including (i) tile information indicating values each uniquely assigned to a different one of the plurality of regions and (ii) relation information indicating that the first region and one of the second regions are related; and generating a bitstream including the connectivity information generated and the encoded three-dimensional points.

Abstract: A three-dimensional data encoding method includes: calculating coefficient values from items of attribute information of three-dimensional points; quantizing the coefficient values to generate quantization values; and generating a bitstream including the quantization values. One or more items of attribute information are classified, for each of three-dimensional spaces, into one of groups, the three-dimensional spaces (i) being included in a plurality of three-dimensional spaces, and (ii) including, among the three-dimensional points, three-dimensional points including the one or more items of attribute information.

Abstract: A three-dimensional data encoding method includes: encoding, for each of three-dimensional points included in point cloud data, geometry information and one or more items of attribute information to generate a bitstream. In the encoding, a normal vector of each of the three-dimensional points is encoded as an item of attribute information included in the one or more items of attribute information of the three-dimensional point.

Abstract: A three-dimensional data encoding method includes: calculating coefficient values from pieces of attribute information of three-dimensional points included in point cloud data; quantizing the coefficient values to generate quantization values; and generating a bitstream including the quantization values. The three-dimensional points corresponding to the coefficient values belong to one layer among one or more layers. Each of a predetermined number of layers among the one or more layers is assigned a quantization parameter for the layer. In the quantizing, (i) when a quantization parameter is assigned to a layer to which each of the coefficient values belongs, the coefficient value is quantized using the quantization parameter, and (ii) when the quantization parameter is not assigned to a layer to which each of the coefficient values belongs, the coefficient value is quantized using a quantization parameter assigned to one layer among the predetermined number of the layers.