CN-121986489-A - Point cloud encoding and decoding method, code stream, encoder, decoder, and storage medium

Abstract

The embodiment of the application discloses a point cloud coding and decoding method, a code stream, an encoder, a decoder and a storage medium, wherein the method comprises the steps of decoding the code stream at a decoding end, and determining prediction mode identification information (101) corresponding to a current RAHT layer; in the case that the prediction mode identification information indicates that the current RAHT layer uses the inter-prediction transform decoding mode, determining a reference block corresponding to the current block according to geometric information of the current block in the current RAHT layer and a reference list, wherein the reference list comprises K decoded units, K is an integer greater than or equal to 1 (102), and determining an attribute transform value corresponding to the current block according to an attribute prediction transform value of the reference block (103).

Inventors

• MA CHUANG

Assignees

• OPPO广东移动通信有限公司

Dates

Publication Date

20260505

Application Date

20231009

Claims (20)

1. A point cloud decoding method applied to a decoder, the method comprising: Decoding the code stream, and determining prediction mode identification information corresponding to a current region adaptive hierarchical transformation RAHT layer; Determining a reference block corresponding to a current block in the current RAHT layer according to geometric information of the current block and a reference list under the condition that the prediction mode identification information indicates that the current RAHT layer uses an inter-prediction transformation decoding mode, wherein the reference list comprises K decoded units, and K is an integer greater than or equal to 1; and determining the attribute transformation value corresponding to the current block according to the attribute prediction transformation value of the reference block.
2. The method of claim 1, wherein, The K decoded units at least comprise K decoded frames corresponding to the current frame, K blocks corresponding to the K decoded frames, or K slices corresponding to the K decoded frames; Or alternatively The K decoded units at least comprise N decoded frames corresponding to the current frame and fusion frames generated based on the N decoded frames, or N blocks corresponding to the N decoded frames and fusion blocks generated based on the N blocks, or N slices corresponding to the N decoded frames and fusion slices generated based on the N slices, wherein N is more than 0 and less than or equal to K.
3. The method of claim 2, wherein the determining the reference block corresponding to the current block according to the geometric information and the reference list of the current block in the current RAHT layer comprises: The reference block is determined from at least one of the decoded units in the reference list based on the geometry information of the current block.
4. The method of claim 3, wherein the determining the reference block from at least one of the decoded units in the reference list based on the geometry information of the current block comprises: and traversing at least one decoded unit in the reference list according to a preset search strategy based on the geometric information of the current block, and determining the reference block.
5. The method of claim 4, wherein the traversing at least one of the decoded units in the reference list according to a preset search strategy based on the geometric information of the current block, determining the reference block, comprises: determining first position information according to the geometric information of the current block; and traversing at least one decoded unit in the reference list according to a preset search strategy based on the first position information, and determining the reference block.
6. The method of claim 5, wherein, The first position information at least comprises geometric information of the current block, geometric information of a parent block of the current block corresponding to the current block, and/or occupation information of the parent block of the current block.
7. The method of claim 6, wherein the preset search strategy comprises at least: Searching for a transform block identical to the geometric information of the current block in the decoded unit and determining the transform block as the reference block, and/or, Searching for a parent transformation block identical to the geometric information of a parent block of the current block in the decoded unit and determining the parent transformation block as the reference block, and/or, Searching for a transform block which is identical to the geometric information of the current block and satisfies a first correlation condition with the occupancy information of the current block in the decoded unit, and determining the transform block as the reference block, and/or, Searching for a transform block in the decoded unit, which is identical to the geometric information of the current block and satisfies a second correlation condition between the corresponding parent transform block and the occupancy information of the parent block of the current block, and determining the transform block as the reference block, and/or, Searching for a transform block which is identical to the geometric information of a parent block of the current block and satisfies a first correlation condition with the occupancy information of the current block in the decoded unit, and determining the transform block as the reference block, and/or, Searching a parent transformation block which is identical to the geometric information of the parent block of the current block and satisfies a second correlation condition with the occupation information of the parent block of the current block in the decoded unit, and determining the parent transformation block as the reference.
8. The method of claim 7, wherein, The first correlation condition comprises that the absolute value of the difference value between the occupation information of the current block and the occupation information of the transformation block is smaller than or equal to a first threshold value, wherein the first threshold value is larger than or equal to 0 and smaller than or equal to 8.
9. The method of claim 7, wherein, The second correlation condition comprises that the absolute value of the difference value between the occupation information of the parent block of the current block and the occupation information of the parent transformation block is smaller than or equal to a second threshold value, wherein the second threshold value is larger than or equal to 0 and smaller than or equal to 8.
10. The method of any of claims 1-9, wherein the number of reference blocks is M, M being an integer greater than or equal to 0 and less than or equal to K.
11. The method of claim 10, wherein the method further comprises: and decoding the code stream and determining an attribute transformation residual value corresponding to the current block.
12. The method of claim 11, wherein the determining the attribute transform value corresponding to the current block from the attribute-predicted transform value of the reference block comprises: Determining an attribute prediction transformation value of the current block according to the attribute prediction transformation value of the reference block; And determining the attribute transformation value corresponding to the current block according to the attribute transformation residual value and the attribute prediction transformation value of the current block.
13. The method of claim 12, wherein the determining the attribute-predicted transform value for the current block from the attribute-predicted transform value for the reference block comprises: and if M is equal to 1, determining the attribute prediction transformation value of the reference block as the attribute prediction transformation value of the current block if the attribute prediction transformation value of the reference block is not 0.
14. The method of claim 12, wherein the determining the attribute-predicted transform value for the current block from the attribute-predicted transform value for the reference block comprises: and if M is equal to 1, determining an adjacent transformation block corresponding to the current block if the attribute prediction transformation value of the reference block is 0, and determining the attribute prediction transformation value of the current block according to the attribute prediction transformation value of the adjacent transformation block.
15. The method of claim 12, wherein the determining the attribute-predicted transform value for the current block from the attribute-predicted transform value for the reference block comprises: And under the condition that M is greater than 1, carrying out average value operation on the attribute prediction transformation values of M reference blocks, and determining the attribute prediction transformation values of the current block.
16. The method of claim 12, wherein the determining the attribute-predicted transform value for the current block from the attribute-predicted transform value for the reference block comprises: determining M distance parameters between the current block and M reference blocks when M is greater than 1; determining M weight parameters corresponding to the attribute prediction transformation values of the M reference blocks based on the M distance parameters; Performing weighted average calculation according to the M weight parameters and the M attribute prediction transformation values of the reference blocks, and determining a transformation average; and determining the transformation average value as an attribute prediction transformation value of the current block.
17. The method of claim 16, wherein the determining M weight parameters corresponding to the attribute-predicted transform values of the M reference blocks based on the M distance parameters comprises: and respectively inputting the M distance parameters into a weight calculation model, and determining the M weight parameters.
18. The method of claim 16, wherein the determining M weight parameters corresponding to the attribute-predicted transform values of the M reference blocks based on the M distance parameters comprises: And determining the M weight parameters according to a weight distribution strategy and the M distance parameters, wherein the weight distribution strategy comprises negative correlation between the distance parameters and the weight parameters.
19. The method of claim 12, wherein the determining the attribute-predicted transform value for the current block from the attribute-predicted transform value for the reference block comprises: determining M space information difference values between the current block and M reference blocks under the condition that M is larger than 1; Determining at least one candidate transformation block in M reference blocks according to the M space-occupying information difference values; and determining the attribute prediction transformation value of the current block according to the attribute prediction transformation value of the candidate transformation block.
20. The method of claim 12, wherein the determining the attribute-predicted transform value for the current block from the attribute-predicted transform value for the reference block comprises: Determining M geometrical information difference values between the current block and M reference blocks when M is greater than 1; determining at least one candidate transformation block in M reference blocks according to the M geometric information difference values; and determining the attribute prediction transformation value of the current block according to the attribute prediction transformation value of the candidate transformation block.

Description

Point cloud encoding and decoding method, code stream, encoder, decoder, and storage medium Technical Field The embodiment of the application relates to the technical field of point cloud coding, in particular to a point cloud coding and decoding method, a code stream, an encoder, a decoder and a storage medium. Background In the point cloud compression (Point Cloud Compression, PCC) framework, for a Geometry-based point cloud compression (G-PCC) codec framework, the Geometry information of the point cloud and the attribute information corresponding to each point are separately encoded. The current G-PCC coding framework includes three attribute coding methods, predictive Transform (PREDICTING TRANSFORM, PT), lifting Transform (Lifting Transform, LT), and Region adaptive hierarchical Transform (Region ADAPTIVE HIERARCHICAL Transform, RAHT). The former two are based on the generation sequence of LOD, and RAHT is based on the construction level of octree to perform self-adaptive transformation on the attribute information from bottom to top. In the process of performing the region adaptive hierarchical inter-frame prediction transform coding, a previous frame of the current frame is generally taken as a reference point cloud sequence frame. However, the limited reference range may limit the performance of the point cloud codec to some extent. Disclosure of Invention The embodiment of the application provides a point cloud encoding and decoding method, a code stream, an encoder, a decoder and a storage medium, which can effectively improve the performance of point cloud encoding and decoding. The technical scheme of the embodiment of the application can be realized as follows: in a first aspect, an embodiment of the present application provides a decoding method, applied to a decoder, including: Decoding the code stream, and determining the prediction mode identification information corresponding to the current RAHT layers; Determining a reference block corresponding to a current block in the current RAHT layer according to geometric information of the current block and a reference list under the condition that the prediction mode identification information indicates that the current RAHT layer uses an inter-prediction transformation decoding mode, wherein the reference list comprises K decoded units, and K is an integer greater than or equal to 1; and determining the attribute transformation value corresponding to the current block according to the attribute prediction transformation value of the reference block. In a second aspect, an embodiment of the present application provides an encoding method, applied to an encoder, including: determining prediction mode identification information corresponding to a current RAHT layer according to a rate distortion optimization algorithm, and writing the prediction mode identification information into a code stream, wherein the prediction mode identification information is used for indicating the current RAHT layer to use an inter-frame prediction transformation coding mode or an intra-frame prediction transformation coding mode; Under the condition that the current RAHT layer uses an inter-frame prediction transformation coding mode, determining a reference block corresponding to a current block in the current RAHT layer according to geometric information of the current block and a reference list, determining an attribute transformation residual value corresponding to the current block according to an attribute prediction transformation value of the reference block, and writing the attribute transformation residual value into a code stream, wherein the reference list comprises K coded units, and K is an integer greater than or equal to 1. In a third aspect, an embodiment of the present application provides a code stream, where the code stream is generated by performing bit encoding according to information to be encoded, where the information to be encoded includes at least one of the following: Prediction mode identification information corresponding to the current RAHT layers, attribute transformation residual values corresponding to the current block, multi-reference prediction identification information and reference sequence numbers corresponding to the current RAHT layers. In a fourth aspect, an embodiment of the present application provides an encoder, where the encoder includes a first determining unit, an encoding unit, The first determining unit is configured to determine prediction mode identification information corresponding to a current RAHT layer according to a rate-distortion optimization algorithm, wherein the prediction mode identification information is used for indicating the current RAHT layer to use an inter-prediction transform coding mode or an intra-prediction transform coding mode; The coding unit is configured to write the prediction mode identification information into a code stream; The first determining unit is further configured to dete