Method and apparatus for point cloud coding
An apparatus for point cloud decoding includes processing circuitry. The processing circuitry receives, from a coded bitstream for a point cloud, encoded occupancy codes for nodes in an octree structure for the point cloud. The nodes in the octree structure correspond to three dimensional (3D) partitions of a space of the point cloud. Sizes of the nodes are associated with sizes of the corresponding 3D partitions. Further, the processing circuitry decodes, from the encoded occupancy codes, occupancy codes for the nodes. At least a first occupancy code for a child node of a first node is decoded without waiting for a decoding of a second occupancy code for a second node having a same node size as the first node. Then, the processing circuitry reconstructs the octree structure based on the decoded occupancy codes for the nodes, and reconstructs the point cloud based on the octree structure.
1. A method for point cloud coding, comprising:
receiving, by a processor and from a coded bitstream for a point cloud, encoded data for nodes in an octree structure for the point cloud, the nodes in the octree structure corresponding to three dimensional (3D) partitions of a space of the point cloud, sizes of the nodes being associated with sizes of the corresponding 3D partitions;
decoding, by the processor and from the encoded data, occupancy codes for the nodes, wherein the decoding the occupancy codes includes
decoding a first portion of the occupancy codes for larger nodes in the nodes using a first coding order, the larger nodes being larger than a threshold node size for coding order change, and
decoding a second portion and a third portion of the occupancy codes for different sets of nodes of smaller nodes in the nodes using a second coding order that is different from the first coding order, the smaller nodes being equal to or smaller than the threshold node size for coding order change;
reconstructing, by the processor, the octree structure based on the decoded occupancy codes for the nodes; and
reconstructing, by the processor, the point cloud based on the octree structure.
2. The method of claim 1 , further comprising:
decoding a first set of occupancy codes for a first set of nodes of the smaller nodes in a first sub octree with a first node being a root of the first sub octree; and
decoding a second set of occupancy codes for a second set of nodes of the smaller nodes in a second sub octree with a second node being a root of the second sub octree, the first node and the second node having a same node size.
3. The method of claim 2 , further comprising:
decoding the first set of occupancy codes for the first set of nodes in the first sub octree in parallel with the decoding of the second set of occupancy codes for the second set of nodes in the second sub octree.
4. The method of claim 2 , further comprising:
decoding, using a first coding mode, the first set of occupancy codes for the first set of nodes in the first sub octree; and
decoding, using a second coding mode, the second set of occupancy codes for the second set of nodes in the second sub octree.
5. The method of claim 4 , further comprising:
decoding, from the coded bitstream, a first index that is indicative of the first coding mode for the first sub octree; and
decoding, from the coded bitstream, a second index that is indicative of the second coding mode for the second sub octree.
6. The method of claim 1 , wherein the first coding order is breadth first coding order and the second coding order is depth first coding order.
7. The method of claim 1 , wherein the first coding order is depth first coding order and the second coding order is breadth first coding order.
8. The method of claim 1 , further comprising:
determining the threshold node size for coding order change based on a signal in the coded bitstream for the point cloud.
9. The method of claim 8 , further comprising:
decoding a control signal from the coded bitstream for the point cloud, the control signal being indicative of a change of coding order.
10. An apparatus for point cloud coding, comprising:
processing circuitry configured to:
receive, from a coded bitstream for a point cloud, encoded data for nodes in an octree structure for the point cloud, the nodes in the octree structure corresponding to three dimensional (3D) partitions of a space of the point cloud, sizes of the nodes being associated with sizes of the corresponding 3D partitions;
decode, from the encoded data, occupancy codes for the nodes, wherein
a first portion of the occupancy codes for larger nodes in the nodes is decoded using a first coding order, the larger nodes being larger than a threshold node size for coding order change, and
a second portion and a third portion of the occupancy codes for different sets of nodes of smaller nodes in the nodes are decoded using a second coding order that is different from the first coding order, the smaller nodes being equal to or smaller than the threshold node size for coding order change:
reconstruct the octree structure based on the decoded occupancy codes for the nodes; and
reconstruct the point cloud based on the octree structure.
11. The apparatus of claim 10 , wherein the processing circuitry is configured to:
decode a first set of occupancy codes for a first set of nodes of the smaller nodes in a first sub octree with a first node being a root of the first sub octree; and
decode a second set of occupancy codes for a second set of nodes of the smaller nodes in a second sub octree with a second node being a root of the second sub octree, the first node and the second node having a same node size.
12. The apparatus of claim 11 , wherein the processing circuitry is configured to:
decode the first set of occupancy codes for the first set of nodes in the first sub octree in parallel with the second set of occupancy codes for the second set of nodes in the second sub octree.
13. The apparatus of claim 11 , wherein the processing circuitry is configured to:
decode, using a first coding mode, the first set of occupancy codes for the first set of nodes in the first sub octree; and
decode, using a second coding mode, second set of occupancy codes for the second set of nodes in the second sub octree.
14. The apparatus of claim 13 , wherein the processing circuitry is configured to:
decode, from the coded bitstream, a first index that is indicative of the first coding mode for the first sub octree; and
decode, from the coded bitstream, a second index that is indicative of the second coding mode for the second sub octree.
15. The apparatus of claim 10 , wherein the first coding order is breadth first coding order and the second coding order is depth first coding order.
16. The apparatus of claim 10 , wherein the first coding order is depth first coding order and the second coding order is breadth first coding order.
17. The apparatus of claim 10 , wherein the processing circuitry is configured to:
determine the threshold node size for coding order change based on a signal in the coded bitstream for the point cloud.
18. The apparatus of claim 17 , wherein the processing circuitry is configured to:
decode a control signal from the coded bitstream for the point cloud, the control signal being indicative of a change of coding order.