Method and apparatus for point cloud compression
Aspects of the disclosure provide methods, apparatuses, and a non-transitory computer-readable medium for point cloud compression and decompression. In a method, syntax information of a point cloud is decoded from a coded bitstream. The syntax information indicates that parallel decoding is to be performed on occupancy codes of nodes in a range of one or more partitioning depths in an octree partitioning structure of the point cloud is determined. The parallel decoding is performed on the occupancy codes of the nodes. The point cloud is reconstructed based on the occupancy codes of the nodes.
1. A method for point cloud coding in a decoder, comprising:
decoding syntax information of a point cloud from a coded bitstream, the syntax information indicating that parallel decoding is to be performed on occupancy codes of nodes in a range of one or more partitioning depths in an octree partitioning structure of the point cloud;
performing the parallel decoding on the occupancy codes of the nodes; and
reconstructing the point cloud based on the occupancy codes of the nodes.
2. The method of claim 1 , wherein the syntax information includes at least one of a first syntax element or a second syntax element, the first syntax element indicating whether the parallel decoding is to be performed on the occupancy codes of the nodes in the range of the one or more partitioning depths in the octree partitioning structure, and the second syntax element indicating a minimum partitioning depth at which the parallel decoding is to be performed.
3. The method of claim 1 , wherein the syntax information is included in at least one of a sequence parameter set, a geometry parameter set, or a geometry slice header.
4. The method of claim 1 , wherein the performing further comprises:
determining, in the coded bitstream, a sub-bitstream for each of the one or more partitioning depths based on a bitstream offset corresponding to each of the one or more partitioning depths; and
performing the parallel decoding on the sub-bitstreams of the one or more partitioning depths.
5. The method of claim 4 , wherein the bitstream offset corresponding to each of the one or more partitioning depths is determined based on the bitstream offset corresponding to a minimum partitioning depth at which the parallel decoding is to be performed and a length of the sub-bitstream corresponding to each of the one or more partitioning depths.
6. The method of claim 1 , wherein the performing further comprises:
performing the parallel decoding on the occupancy codes of the nodes in the range of the one or more partitioning depths based on a look-up table which tracks most frequent occupancy codes, the look-up table being initialized for each of the one or more partitioning depths.
7. The method of claim 6 , further comprising:
determining initial values of the look-up table for each of the one or more partitioning depths based on values of the look-up table corresponding to a partition depth that is one less than a minimum partitioning depth at which the parallel decoding is to be performed.
8. The method of claim 1 , wherein the performing further comprises:
performing the parallel decoding on the occupancy codes of the nodes in the range of the one or more partitioning depths based on a planar coding mode, values of the planar coding mode being initialized for each of the one or more partitioning depths.
9. The method of claim 8 , further comprising:
determining initial values of the planar coding mode for each of the one or more partitioning depths based on the values of the planar coding mode corresponding to a partition depth that is one less than a minimum partitioning depth at which the parallel decoding is to be performed.
10. An apparatus for point cloud coding, comprising processing circuitry configured to:
decode syntax information of a point cloud from a coded bitstream, the syntax information indicating that parallel decoding is to be performed on occupancy codes of nodes in a range of one or more partitioning depths in an octree partitioning structure of the point cloud;
perform the parallel decoding on the occupancy codes of the nodes; and
reconstruct the point cloud based on the occupancy codes of the nodes.
11. The apparatus of claim 10 , wherein the syntax information includes at least one of a first syntax element or a second syntax element, the first syntax element indicating whether the parallel decoding is to be performed on the occupancy codes of the nodes in the range of the one or more partitioning depths in the octree partitioning structure, and the second syntax element indicating a minimum partitioning depth at which the parallel decoding is to be performed.
12. The apparatus of claim 10 , wherein the syntax information is included in at least one of a sequence parameter set, a geometry parameter set, or a geometry slice header.
13. The apparatus of claim 10 , wherein the processing circuitry is further configured to:
determine, in the coded bitstream, a sub-bitstream for each of the one or more partitioning depths based on a bitstream offset corresponding to each of the one or more partitioning depths; and
perform the parallel decoding on the sub-bitstreams of the one or more partitioning depths.
14. The apparatus of claim 13 , wherein the bitstream offset corresponding to each of the one or more partitioning depths is determined based on the bitstream offset corresponding to a minimum partitioning depth at which the parallel decoding is to be performed and a length of the sub-bitstream corresponding to each of the one or more partitioning depths.
15. The apparatus of claim 10 , wherein the processing circuitry is further configured to:
perform the parallel decoding on the occupancy codes of the nodes in the range of the one or more partitioning depths based on a look-up table which tracks most frequent occupancy codes, the look-up table being initialized for each of the one or more partitioning depths.
16. The apparatus of claim 15 , wherein the processing circuitry is further configured to:
determine initial values of the look-up table for each of the one or more partitioning depths based on values of the look-up table corresponding to a partition depth that is one less than a minimum partitioning depth at which the parallel decoding is to be performed.
17. The apparatus of claim 10 , wherein the processing circuitry is further configured to:
perform the parallel decoding on the occupancy codes of the nodes in the range of the one or more partitioning depths based on a planar coding mode, values of the planar coding mode being initialized for each of the one or more partitioning depths.
18. The apparatus of claim 17 , wherein the processing circuitry is further configured to:
determine initial values of the planar coding mode for each of the one or more partitioning depths based on the values of the planar coding mode corresponding to a partition depth that is one less than a minimum partitioning depth at which the parallel decoding is to be performed.
19. A non-transitory computer-readable medium storing instructions which when executed by a computer for point cloud coding cause the computer to perform:
decoding syntax information of a point cloud from a coded bitstream, the syntax information indicating that a parallel decoding is to be performed on occupancy codes of nodes in a range of one or more partitioning depths in an octree partitioning structure of the point cloud;
performing the parallel decoding on the occupancy codes of the nodes; and
reconstructing the point cloud based on the occupancy codes of the nodes.
20. The non-transitory computer-readable medium of claim 19 , wherein the syntax information includes at least one of a first syntax element or a second syntax element, the first syntax element indicating whether the parallel decoding is to be performed on the occupancy codes of the nodes in the range of the one or more partitioning depths in the octree partitioning structure, and the second syntax element indicating a minimum partitioning depth at which the parallel decoding is to be performed.