Spatial scalable coding for point cloud coding

1. A method of decoding comprising:

receiving an entropy coded bitstream comprising compressed video data including point cloud occupancy codes;

generating one or more dequantized dimensions of a boundary box of a point cloud by a process comprising:

parsing dimensions of the boundary box of the point cloud from the entropy coded bitstream;

entropy-decoding the parsed dimensions of the boundary box of the point cloud; and

dequantizing the dimensions of the boundary box of the point cloud;

determining whether a node or node depth has attribute information;

based on determining that the node or node depth has attribute information, using the attribute information for the node or node depth; and

based on determining that the node or node depth does not have attribute information, obtaining attribute information for the node or node depth by inheriting attribute information from a node or node depth that is at least one depth level in an octree of the point cloud above a depth level of the node or node depth in the octree.

2. The method of claim 1 , wherein the node or node depth that is the at least one depth level in the octree above the depth level of the node or node depth is an intermediate node.

3. The method of claim 1 , wherein the inheriting of the attribute information from the node or node depth that is the at least one depth level in the octree above the depth level of the node or node depth includes averaging attribute values in the node or node depth that is the at least one depth level above.

4. The method of claim 1 , wherein the inheriting of the attribute information from the node or node depth that is the at least one depth level in the octree above the depth level of the node or node depth includes using a min/max function based on attribute values in the node or node depth that is the at least one depth level above.

5. The method of claim 1 , wherein the inheriting of the attribute information from the node or node depth that is the at least one depth level in the octree above the depth level of the node or node depth includes using only a subset that is less than an entire set of attribute values in the node or node depth that is the at least one depth level above.

6. The method of claim 5 , wherein the subset includes only children nodes or a subset of children nodes.

7. The method of claim 6 , wherein the subset includes only the children nodes within a center sphere distance threshold of the middle.

8. The method of claim 1 , further comprising:

grouping descendant nodes corresponding to a same ancestor node together.

9. The method of claim 1 , wherein the inheriting of the attribute information from the node or node depth that is the at least one depth level in the octree above the depth level of the node or node depth comprises computing a weighted average of attribute values in the node or node depth that is the at least one depth level above.

10. The method of claim 1 , further comprising: using attributes of a parent level or an ancestor level as a predictor.

11. The method of claim 1 , further comprising: using attribute information of a node at an octree depth as a predictor for attributes of descendant nodes of the node at the octree depth.

12. The method of claim 1 , further comprising: using attribute information of a node at an octree depth as predictor candidates for attributes of descendant nodes of the node at the octree depth.

13. The method of claim 12 , further comprising:

using rate distortion optimization to select a best predictor candidate as a final predictor for attribute information of one of the descendant nodes of the node at the octree depth.

14. The method of claim 1 , wherein attributes of the point cloud include one or more of color or reflectance.

15. The method of claim 1 , further comprising:

generating a displayable image based at least in part on the inherited attribute information; and

performing control so that the displayable image is displayed by a display.

16. The method of claim 1 , further comprising:

building an octree structure by subdividing the boundary box of the point cloud according to the dequantized dimensions of the boundary box including the point cloud occupancy codes of the point cloud by using the inherited attribute information.

17. A computer system for decoding video data, the computer system comprising:

one or more computer-readable non-transitory storage media configured to store computer program code; and

one or more computer processors configured to access said computer program code and operate as instructed by said computer program code, said computer program code including:

receiving code configured to cause the one or more computer processors to receive an entropy coded bitstream comprising compressed video data including point cloud occupancy codes;

dequantization code configured to cause the one or more computer processors to generate one or more dequantized dimensions of a boundary box of the point cloud by a process comprising: parsing dimensions of the boundary box of the point cloud from the entropy coded bitstream, entropy-decoding the parsed dimensions of the boundary box of the point cloud, and dequantizing the dimensions of the boundary box of the point cloud;

determining code configured to cause the one or more computer processors to determine whether a node or node depth has attribute information;

attribute identification code configured to cause the one or more computer processors to:

based on determining that the node or node depth has attribute information, use the attribute information for the node or node depth; and

based on determining that the node or node depth does not have attribute information, obtain attribute information for the node or node depth by inheriting attribute information from a node or node depth that is at least one depth level in an octree of the point cloud above a depth level of the node or node depth in the octree.

18. The computer system of claim 17 , further comprising:

a display, wherein the computer program code further comprises: display code configured to cause the at one or more processors to: generate a displayable image based at least in part on the inherited attribute information, and perform control so that the displayable image is displayed by the display.

19. A non-transitory computer readable medium having stored thereon a computer program for decoding video data, the computer program configured to cause one or more computer processors to:

receive an entropy coded bitstream comprising compressed video data including point cloud occupancy codes;

generate one or more dequantized dimensions of a boundary box of a point cloud by a process comprising:

parsing dimensions of the boundary box of the point cloud from the entropy coded bitstream;

entropy-decoding the parsed dimensions of the boundary box of the point cloud; and

dequantizing the dimensions of the boundary box of the point cloud;

determine whether a node or node depth has attribute information;

based on determining that the node or node depth has attribute information, use the attribute information for the node or node depth; and

based on determining that the node or node depth does not have attribute information, obtain attribute information for the node or node depth by inheriting attribute information from a node or node depth that is at least one depth level in an octree of the point cloud above a depth level of the node or node depth in the octree.

20. The non-transitory computer-readable medium of claim 19 , wherein the computer program is configured to cause the one or more computer processors to:

generate a displayable image based at least in part on the inherited attribute information; and

perform control so that the displayable image is displayed by a display.