Three-dimensional data encoding method, three-dimensional data decoding method, three-dimensional data encoding device, and three-dimensional data decoding device

1. A three-dimensional data encoding method, comprising:

setting a hierarchical structure for items of geometry information of three-dimensional points included in point cloud data, the hierarchical structure having first layers and second layers, each of the second layers having one or more of the first layers;

encoding the items of geometry information on a per first layer basis to generate items of first encoded data each for a different one of the first layers; and

generating a bitstream including items of second encoded data which are items of encoded data for respective second layers, the items of second encoded data each including one or more items of first encoded data of one or more first layers included in a second layer corresponding to the item of second encoded data,

wherein the bitstream includes an item of second information indicating a total number of first layers included in each of the second layers, and

each of the items of first encoded data includes an occupancy code.

2. The three-dimensional data encoding method according to claim 1 ,

wherein the bitstream includes:

an item of first information indicating a data length of each of the items of second encoded data; and

an item of third information indicating a data length of each of the items of first encoded data.

3. The three-dimensional data encoding method according to claim 2 ,

wherein the bitstream includes a first header which is common to the items of second encoded data, and

the first header includes the item of first information.

4. The three-dimensional data encoding method according to claim 2 ,

wherein the bitstream includes second headers each for a different one of the items of second encoded data,

the item of first information includes items of fourth information each corresponding to a different one of the items of second encoded data and indicating a data length of the item of second encoded data to which the item of fourth information corresponds, and

each of the second headers includes an item of fourth information indicating a data length of an item of second encoded data corresponding to the second header, the item of fourth information being included in the items of fourth information, the item of second encoded data being included in the items of second encoded data.

5. The three-dimensional data encoding method according to claim 2 ,

wherein the bitstream includes third headers each for a different one of the items of first encoded data,

the item of first information includes:

an item of second information indicating a total number of first layers included in each of the second layers; and

items of fifth information each corresponding to a different one of the items of first encoded data and indicating a data length of the item of first encoded data to which the fifth information corresponds, and

each of the third headers includes an item of fifth information indicating a data length of an item of first encoded data corresponding to the third header, the item of fifth information being included in the items of fifth information, the item of first encoded data being included in the items of first encoded data.

6. The three-dimensional data encoding method according to claim 1 , further comprising:

encoding items of attribute information of the three-dimensional points on a per first layer basis to generate items of third encoded data each for a different one of the first layers,

wherein the bitstream includes items of fourth encoded data which are items of encoded data for respective second layers, the items of fourth encoded data each including one or more items of third encoded data of one or more first layers included in a second layer corresponding to the item of fourth encoded data, and

the bitstream includes an item of sixth information indicating a data length of each of the items of fourth encoded data.

7. The three-dimensional data encoding method according to claim 1 ,

wherein the first layers are layers of an octree indicating positions of the three-dimensional points.

8. A three-dimensional data decoding method, comprising:

obtaining encoded point cloud data where a hierarchical structure is set, the hierarchical structure having first layers and second layers, each of the second layers having one or more of the first layers;

obtaining at least one item of second encoded data corresponding to one of the second layers and including one or more items of first encoded data each for a different one of the first layers;

obtaining information indicating a total number of first layers included in the second layer corresponding to the at least one item of second encoded data obtained; and

decoding the at least one item of second encoded data obtained using the information,

wherein each of the items of first encoded data includes an occupancy code.

9. The three-dimensional data decoding method according to claim 8 ,

wherein the bitstream includes:

an item of first information indicating a data length of each of the items of second encoded data; and

an item of third information indicating a data length of each of the items of first encoded data.

10. The three-dimensional data decoding method according to claim 9 ,

wherein the bitstream includes a first header which is common to the items of second encoded data, and

the first header includes the item of first information.

11. The three-dimensional data decoding method according to claim 9 ,

wherein the bitstream includes second headers each for a different one of the items of second encoded data,

the item of first information includes items of fourth information each corresponding to a different one of the items of second encoded data and indicating a data length of the item of second encoded data to which the item of fourth information corresponds, and

each of the second headers includes an item of fourth information indicating a data length of an item of second encoded data corresponding to the second header, the item of fourth information being included in the items of fourth information, the item of second encoded data being included in the items of second encoded data.

12. The three-dimensional data decoding method according to claim 9 ,

wherein the bitstream includes third headers each for a different one of the items of first encoded data,

the item of first information includes:

an item of second information indicating a total number of first layers included in each of the second layers; and

items of fifth information each corresponding to a different one of the items of first encoded data and indicating a data length of the item of first encoded data to which the fifth information corresponds, and

each of the third headers includes an item of fifth information indicating a data length of an item of first encoded data corresponding to the third header, the item of fifth information being included in the items of fifth information, the item of first encoded data being included in the items of first encoded data.

13. The three-dimensional data decoding method according to claim 8 ,

wherein the bitstream includes items of third encoded data each for a different one of the first layers, the items of third encoded data being generated by encoding items of attribute information of the three-dimensional points on a per first layer basis,

the bitstream includes items of fourth encoded data which are items of encoded data for respective second layers, the items of fourth encoded data each including one or more items of third encoded data of one or more first layers included in a layer corresponding to the item of fourth encoded data,

the bitstream includes an item of sixth information indicating a data length of each of the items of fourth encoded data,

the three-dimensional data decoding method further comprising:

obtaining the item of sixth information from the bitstream;

obtaining at least one item of fourth encoded data from among the items of fourth encoded data, using the item of sixth information; and

decoding the at least one item of fourth encoded data obtained.

14. The three-dimensional data decoding method according to claim 8 ,

wherein the first layers are layers of an octree indicating positions of the three-dimensional points.

15. A three-dimensional data encoding device, comprising:

a processor; and

memory,

wherein using the memory, the processor:

sets a hierarchical structure for items of geometry information of three-dimensional points included in point cloud data, the hierarchical structure having first layers and second layers, each of the second layers having one or more of the first layers;

encodes the items of geometry information on a per first layer basis to generate items of first encoded data each for a different one of the first layers; and

generates a bitstream including items of second encoded data which are items of encoded data for respective second layers, the items of second encoded data each including one or more items of first encoded data of one or more first layers included in a second layer corresponding to the item of second encoded data,

wherein the bitstream includes an item of second information indicating a total number of first layers included in each of the second layers, and

each of the items of first encoded data includes an occupancy code.

16. A three-dimensional data decoding device, comprising:

a processor; and

memory,

wherein using the memory, the processor:

obtains encoded point cloud data where a hierarchical structure is set, the hierarchical structure having first layers and second layers, each of the second layers having one or more of the first layers;

obtains at least one item of second encoded data corresponding to one of the second layers and including one or more items of first encoded data each for a different one of the first layers;

obtains information indicating a total number of first layers included in the second layer corresponding to the at least one item of second encoded data obtained; and

decodes the at least one item of second encoded data obtained using the information,

wherein each of the items of first encoded data includes an occupancy code.