Temporal scalability in geometry point cloud compression (G-PCC)

1. A method of decoding point cloud data, the method comprising:

determining a value of a temporal identifier (ID) of a syntax structure associated with a geometry data unit;

wherein the temporal ID of the syntax structure identifies a temporal layer to which point cloud data associated with the syntax structure belongs; and

inferring a value of a temporal ID associated with an attribute data unit that corresponds to the geometry data unit to be equal to the value of the temporal ID associated with the geometry data unit; and

decoding the point cloud data based on the value of the temporal ID,

wherein decoding the point cloud data based on the value of the temporal ID comprises decoding the geometry data unit and decoding the attribute data unit.

2. The method of claim 1 , further comprising:

determining a value of a flag indicative of whether the temporal ID is in the syntax structure.

3. The method of claim 1 , wherein the temporal ID is a first temporal ID and the syntax structure is associated with a first slice of a frame, the method further comprising:

determining a second temporal ID associated with a second slice of the frame to be equal to the first temporal ID; and

decoding the second slice of the frame based on the second temporal ID.

4. The method of claim 1 , wherein the syntax structure is a first syntax structure associated with an independent slice and the temporal ID is a first temporal ID, the method further comprising:

determining a second temporal ID associated with a dependent slice, the dependent slice being dependent on the independent slice; and

decoding the dependent slice based on the independent slice and the second temporal ID,

wherein the second temporal ID is equal to or greater than the first temporal ID.

5. The method of claim 1 , wherein the point cloud data comprises a plurality of frames of point cloud data, wherein a first frame of point cloud data of the plurality of frames of point cloud data comprises a plurality of slices, and wherein each slice of the plurality of slices is associated with a same temporal ID.

6. The method of claim 1 , wherein the point cloud data comprises a first frame of point cloud data and a second frame of point cloud data, wherein the first frame of point cloud data comprises a first slice associated with a first temporal ID t 1 and the second frame of point cloud data comprises a second slice associated with a second temporal ID t 2 , where t 2 >t 1 , further comprising:

decoding the first slice without depending on the second slice.

7. A method of encoding point cloud data, the method comprising:

determining a value of a temporal identifier (ID) of a syntax structure associated with a geometry data unit,

wherein the temporal ID of the syntax structure identifies a temporal layer to which point cloud data associated with the syntax structure belongs; and

refraining from signaling a value of a temporal ID associated with an attribute data unit that corresponds to the geometry data unit; and

encoding the point cloud data to include the temporal ID in the syntax structure.

8. The method of claim 7 , further comprising:

signaling a flag whose value is indicative of the temporal ID being in the syntax structure.

9. The method of claim 7 , wherein the temporal ID is a first temporal ID and the syntax structure is a first syntax structure associated with a first slice of a frame, further comprising:

determining a second temporal ID associated with a second slice of the frame to be equal to the first temporal ID; and

encoding a second syntax structure associated with the second slice to include the second temporal ID.

10. The method of claim 7 , wherein the syntax structure is a first syntax structure associated with an independent slice and the temporal ID is a first temporal ID, further comprising:

determining a second temporal ID associated with a dependent slice, the dependent slice being dependent on the independent slice; and

encoding the point cloud data to include the second temporal ID in a second syntax structure for the dependent slice,

wherein the second temporal ID is equal to or greater than the first temporal ID.

11. The method of claim 7 , wherein the point cloud data comprises a plurality of frames of point cloud data, wherein a first frame of point cloud data of the plurality of frames of point cloud data comprises a plurality of slices, and wherein each slice of the plurality of slices is associated with a same temporal ID.

12. The method of claim 7 , wherein the point cloud data comprises a first frame of point cloud data and a second frame of point cloud data, wherein the first frame of point cloud data comprises a first slice associated with a first temporal ID t 1 and the second frame of point cloud data comprises a second slice associated with a second temporal ID t 2 , where t 2 >t 1 , further comprising:

encoding the first slice such that a decoder decodes the first slice without depending on the second slice.

13. A device for decoding point cloud data, the device comprising:

memory configured to store the point cloud data; and

one or more processors implemented in circuitry and communicatively coupled to the memory, the one or more processors being configured to:

determine a value of a temporal identifier (ID) of a syntax structure associated with a geometry data unit,

wherein the temporal ID of the syntax structure identifies a temporal layer to which point cloud data associated with the syntax structure belongs; and

infer a value of a temporal ID associated with an attribute data unit that corresponds to the geometry data unit to be equal to the value of the temporal ID associated with the geometry data unit; and

decode the point cloud data based on the value of the temporal ID,

wherein as part of decoding the point cloud data based on the value of the temporal ID, the one or more processors are configured to decode the geometry data unit and decode the attribute data unit.

14. The device of claim 13 , wherein the one or more processors are further configured to:

determine a value of a flag indicative of whether the temporal ID is in the syntax structure.

15. The device of claim 13 , wherein the temporal ID is a first temporal ID and the syntax structure is associated with a first slice of a frame, and wherein the one or more processors are further configured to:

determine a second temporal ID associated with a second slice of the frame to be equal to the first temporal ID; and

decode the second slice of the frame based on the second temporal ID.

16. The device of claim 13 , wherein the syntax structure is a first syntax structure associated with an independent slice and the temporal ID is a first temporal ID, and wherein the one or more processors are further configured to:

determine a second temporal ID associated with a dependent slice, the dependent slice being dependent on the independent slice; and

decode the dependent slice based on the independent slice and the second temporal ID,

wherein the second temporal ID is equal to or greater than the first temporal ID.

17. The device of claim 13 , wherein the point cloud data comprises a plurality of frames of point cloud data, wherein a first frame of point cloud data of the plurality of frames of point cloud data comprises a plurality of slices, and wherein each slice of the plurality of slices is associated with a same temporal ID.

18. The device of claim 13 , wherein the point cloud data comprises a first frame of point cloud data and a second frame of point cloud data, wherein the first frame of point cloud data comprises a first slice associated with a first temporal ID t 1 and the second frame of point cloud data comprises a second slice associated with a second temporal ID t 2 , where t 2 >t 1 , and wherein the one or more processors are further configured to:

decode the first slice without depending on the second slice.

19. The device of claim 13 , further comprising a display configured to display the point cloud data.

20. A device for encoding point cloud data, the device comprising:

memory configured to store the point cloud data; and

one or more processors implemented in circuitry and communicatively coupled to the memory, the one or more processors being configured to:

determine a value of a temporal identifier (ID) of a syntax structure associated with a geometry data unit,

wherein the temporal ID of the syntax structure identifies a temporal layer to which point cloud data associated with the syntax structure belongs; and

refrain from signaling a value of a temporal ID associated with an attribute data unit that corresponds to the geometry data unit; and

encode the point cloud data to include the temporal ID in the syntax structure.

21. The device of claim 20 , wherein the one or more processors are further configured to:

signal a flag whose value is indicative of the temporal ID being in the syntax structure.

22. The device of claim 20 , wherein the temporal ID is a first temporal ID and the syntax structure is a first syntax structure associated with a first slice of a frame, and wherein the one or more processors are further configured to:

determine a second temporal ID associated with a second slice of the frame to be equal to the first temporal ID; and

encode a second syntax structure associated with the second slice to include the second temporal ID.

23. The device of claim 20 , wherein the syntax structure is a first syntax structure associated with an independent slice and the temporal ID is a first temporal ID, and wherein the one or more processors are further configured to:

determine a second temporal ID associated with a dependent slice, the dependent slice being dependent on the independent slice; and

encode the point cloud data to include the second temporal ID in a second syntax structure for the dependent slice,

wherein the second temporal ID is equal to or greater than the first temporal ID.

24. The device of claim 20 , wherein the point cloud data comprises a plurality of frames of point cloud data, wherein a first frame of point cloud data of the plurality of frames of point cloud data comprises a plurality of slices, and wherein each slice of the plurality of slices is associated with a same temporal ID.

25. The device of claim 20 , wherein the point cloud data comprises a first frame of point cloud data and a second frame of point cloud data, wherein the first frame of point cloud data comprises a first slice associated with a first temporal ID t 1 and the second frame of point cloud data comprises a second slice associated with a second temporal ID t 2 , where t 2 >t 1 , and wherein the one or more processors are further configured to:

encode the first slice such that a decoder decodes the first slice without depending on the second slice.

26. The device of claim 20 , wherein the device comprises a vehicle.