Point cloud data transmission device, point cloud data transmission method, point cloud data reception device, and point cloud data reception method

1. A method for receiving point cloud data by a receiving apparatus, the method comprising:

receiving a bitstream including point cloud data;

decoding geometry data of the point cloud data partially,

wherein the decoded geometry data is represented based on an octree, and

wherein a geometry position of a node in a level of the octree is reconstructed based on a center position of the node for spatial scalability at the level of Levels of Detail (LoDs) of the octree that are skipped from a bottom of the octree; and

decoding attribute data of the point cloud data based on the reconstructed geometry position.

2. The method of claim 1 ,

wherein a first node of the octree is reconstructed based on a center position of the first node,

wherein a second node of the octree is reconstructed based on a center position of the second node, and

wherein the first node and the second node are not a leaf node of the octree.

3. An apparatus for receiving point cloud data, the apparatus comprising:

a receiver configured to receive a bitstream including point cloud data;

a decoder configured to:

decode geometry data of the point cloud data partially,

wherein the decoded geometry data is represented based on an octree, and

wherein a geometry position of a node in a level of the octree is reconstructed based on a center position of the node for spatial scalability at the level of Levels of Detail (LoDs) of the octree that are skipped from a bottom of the octree; and

decode attribute data of the point cloud data based on the reconstructed geometry position.

4. The apparatus of claim 3 ,

wherein a first node of the octree is reconstructed based on a center position of the first node,

wherein a second node of the octree is reconstructed based on a center position of the second node, and

wherein the first node and the second node are not a leaf node of the octree.

5. A method for transmitting point cloud data, the method comprising:

encoding geometry data of point cloud data,

wherein the encoded geometry data is represented based on an octree, and

wherein a node in a level of the octree is reconstructed based on a center position of the node for spatial scalability at the level of Levels of Detail (LoDs) of the octree that are skipped from a bottom of the octree;

encoding attribute data of the point cloud data based on the reconstructed geometry position; and

transmitting a bitstream including the geometry data and the attribute data of the point cloud data.

6. The method of claim 5 ,

wherein a first node of the octree is reconstructed based on a center position of the first node,

wherein a second node of the octree is reconstructed based on a center position of the second node, and

wherein the first node and the second node are not a leaf node of the octree.

7. An apparatus for transmitting point cloud data, the apparatus comprising:

encoding geometry data of point cloud data,

wherein the encoded geometry data is represented based on an octree, and

wherein a geometry position of a node in a level of the octree is reconstructed based on a center position of the node for spatial scalability at the level of Levels of Detail (LoDs) of the octree that are skipped from a bottom of the octree;

encoding attribute data of the point cloud data based on the reconstructed geometry position; and

transmitting a bitstream including the geometry data and the attribute data of the point cloud data.

8. The apparatus of claim 7 ,

wherein a first node of the octree is reconstructed based on a center position of the first node,

wherein a second node of the octree is reconstructed based on a center position of the second node, and

wherein the first node and the second node are not a leaf node of the octree.