Method and apparatus for point cloud compression
Aspects of the disclosure provide methods, apparatuses, and a non-transitory computer-readable medium for point cloud coding. In a method, when parallel octree coding is enabled for occupancy codes of nodes in an octree partitioning structure of the point cloud, syntax information of the point cloud is decoded from a coded bitstream and a bitstream offset of an octree depth is determined. The syntax information indicates a bitstream length of the octree depth at which the parallel octree coding is enabled. Parallel decoding is performed on the occupancy codes of the nodes of the octree depth based on the bitstream offset and the bitstream length of the octree depth. Further, the point cloud is reconstructed based on the occupancy codes of the nodes.
1. A method for point cloud coding in a decoder, comprising:
when parallel octree coding is enabled for occupancy codes of nodes in an octree partitioning structure of the point cloud,
decoding syntax information of the point cloud from a coded bitstream, the syntax information indicating a bitstream length of an octree depth at which the parallel octree coding is enabled, and
determining a bitstream offset of the octree depth;
performing parallel decoding on the occupancy codes of the nodes of the octree depth based on the bitstream offset and the bitstream length of the octree depth; and
reconstructing the point cloud based on the occupancy codes of the nodes.
2. The method of claim 1 , wherein the determining the bitstream offset comprises:
determining the bitstream offset of the octree depth based on a bitstream offset of a minimal octree depth of one or more octree depths at which the parallel octree coding is enabled.
3. The method of claim 2 , wherein the syntax information indicates the bitstream offset of the minimal octree depth when the parallel octree coding is enabled.
4. The method of claim 2 , wherein the bitstream offset of the minimal octree depth is inferred.
5. The method of claim 2 , wherein the syntax information indicates the bitstream length of each of the one or more octree depths.
6. The method of claim 2 , wherein
the one or more octree depths includes a plurality of octree depths, and
the determining the bitstream offset includes determining a bitstream offset for each of the plurality of octree depths based on the bitstream offset of the minimal octree depth.
7. The method of claim 5 , further comprising:
determining that the parallel octree coding is enabled when the minimal octree depth indicated by the syntax information is greater than 0,
wherein the decoding the syntax information includes decoding the syntax information of the point cloud based on the minimal octree depth.
8. The method of claim 1 , wherein the syntax information is included in a geometry slice header.
9. An apparatus, comprising:
processing circuitry configured to:
when parallel octree coding is enabled for occupancy codes of nodes in an octree partitioning structure of a point cloud,
decode syntax information of the point cloud from a coded bitstream, the syntax information indicating a bitstream length of an octree depth at which the parallel octree coding is enabled, and
determine a bitstream offset of the octree depth;
perform parallel decoding on the occupancy codes of the nodes of the octree depth based on the bitstream offset and the bitstream length of the octree depth; and
reconstruct the point cloud based on the occupancy codes of the nodes.
10. The apparatus of claim 9 , wherein the processing circuitry is configured to:
determine the bitstream offset of the octree depth based on a bitstream offset of a minimal octree depth of one or more octree depths at which the parallel octree coding is enabled.
11. The apparatus of claim 10 , wherein the syntax information indicates the bitstream offset of the minimal octree depth when the parallel octree coding is enabled.
12. The apparatus of claim 10 , wherein the bitstream offset of the minimal octree depth is inferred.
13. The apparatus of claim 10 , wherein the syntax information indicates the bitstream length of each of the one or more octree depths.
14. The apparatus of claim 10 , wherein
the one or more octree depths includes a plurality of octree depths, and
the processing circuitry is configured to determine a bitstream offset for each of the plurality of octree depths based on the bitstream offset of the minimal octree depth.
15. The apparatus of claim 13 , wherein the processing circuitry is configured to:
determine that the parallel octree coding is enabled when the minimal octree depth indicated by the syntax information is greater than 0, and
decode the syntax information of the point cloud based on the minimal octree depth.
16. The apparatus of claim 9 , wherein the syntax information is included in a geometry slice header.
17. A non-transitory computer-readable medium storing instructions which when executed by a computer for point cloud coding cause the computer to perform:
when parallel octree coding is enabled for occupancy codes of nodes in an octree partitioning structure of the point cloud,
decoding syntax information of the point cloud from a coded bitstream, the syntax information indicating a bitstream length of an octree depth at which the parallel octree coding is enabled, and
determining a bitstream offset of the octree depth;
performing parallel decoding on the occupancy codes of the nodes of the octree depth based on the bitstream offset and the bitstream length of the octree depth; and
reconstructing the point cloud based on the occupancy codes of the nodes.
18. The non-transitory computer-readable medium of claim 17 , wherein the determining the bitstream offset comprises:
determining the bitstream offset of the octree depth based on a bitstream offset of a minimal octree depth of one or more octree depths at which the parallel octree coding is enabled.
19. The non-transitory computer-readable medium of claim 18 , wherein the syntax information indicates the bitstream offset of the minimal octree depth when the parallel octree coding is enabled.
20. The non-transitory computer-readable medium of claim 18 , wherein the bitstream offset of the minimal octree depth is inferred.