US-20260127773-A1 - HIGH-LEVEL SYNTAX FOR POLYGON COMPRESSION

Abstract

A method of encoding performed by at least one processor includes receiving a polygon mesh comprising a plurality of vertices defining a plurality of faces; determining a mesh face type of the polygon mesh; dividing the polygon mesh into a plurality of sub-meshes; generating a sub-mesh header for at least one sub-mesh from the plurality of sub-meshes in accordance with at least the mesh face type of the polygon mesh; and generating a bitstream comprising the polygon mesh and the sub-mesh header.

Inventors

• Chao Huang
• Shan Liu

Assignees

• Tencent America LLC

Dates

Publication Date

20260507

Application Date

20250818

Claims (20)

1. 1 . A method of encoding performed by at least one processor, the method comprising: receiving a polygon mesh comprising a plurality of vertices defining a plurality of faces; determining a mesh face type of the polygon mesh; dividing the polygon mesh into a plurality of sub-meshes; generating a sub-mesh header for at least one sub-mesh from the plurality of sub-meshes in accordance with at least the mesh face type of the polygon mesh; and generating a bitstream comprising the polygon mesh and the sub-mesh header.
2. 2 . The method according to claim 1 , wherein when the mesh face type indicates that the polygon mesh comprises more than one type of faces, the sub-mesh header comprises a submesh_face_type indicating a face type of the at least one sub-mesh.
3. 3 . The method according to claim 1 , wherein the mesh face type is one of a first face type indicating that the polygon mesh comprises triangle faces, a second face type indicating that the polygon mesh comprises quadrilateral faces, a third face type indicating that the polygon mesh comprises both triangle and quadrilateral faces, and a fourth face type indicating the polygon mesh contains polygon faces.
4. 4 . The method according to claim 1 , wherein the sub-mesh header further comprises a parameter indicating whether all connected components in the at least one sub-mesh have a same connectivity.
5. 5 . The method according to claim 1 , wherein the sub-mesh header further comprises a prediction strategy indicating how a vertex in the at least one sub-mesh is encoded based on one or more vertices in the at least one sub-mesh.
6. 6 . The method according to claim 5 , wherein the prediction strategy is a parallelogram prediction strategy.
7. 7 . The method according to claim 5 , wherein the sub-mesh header further comprises a parameter indicating at least one of a singleway prediction mode and a multiway prediction mode.
8. 8 . The method according to claim 7 , wherein the singleway prediction mode in which the vertex is encoded in accordance with the prediction strategy using at least one side of the sub-mesh header.
9. 9 . The method according to claim 7 , wherein the multiway prediction mode in which the vertex is encoded in accordance with the prediction strategy using at least two sides of the sub-mesh header.
10. 10 . The method according to claim 1 , wherein the sub-mesh header comprises an indices coding strategy that indicates one of a polygon-fan method and a dual-degree method.
11. 11 . The method according to claim 10 , wherein the sub-mesh header comprises a traversal strategy based on determining that the indices coding strategy indicates the polygon-fan method.
12. 12 . A decoding method performed by at least one processor, the method comprising: receiving a bitstream comprising a polygon mesh and a sub-mesh header, the polygon mesh divided into a plurality of sub-meshes; decoding at least one sub-mesh from the plurality of sub-meshes in accordance with the sub-mesh header, wherein the sub-mesh header is generated based on a mesh face type of the polygon mesh.
13. 13 . The decoding method according to claim 12 , wherein when the mesh face type indicates that the polygon mesh comprises more than one type of faces, the sub-mesh header comprises a submesh_face_type indicating a face type of the at least one sub-mesh.
14. 14 . The decoding method according to claim 12 , wherein the mesh face type is one of a first face type indicating that the polygon mesh comprises triangle faces, a second face type indicating that the polygon mesh comprises quadrilateral faces, a third face type indicating that the polygon mesh comprises both triangle and quadrilateral faces, and a fourth face type indicating the polygon mesh contains polygon faces.
15. 15 . The decoding method according to claim 12 , wherein the sub-mesh header further comprises a parameter indicating whether all connected components in the at least one sub-mesh have a same connectivity.
16. 16 . The decoding method according to claim 12 , wherein the sub-mesh header further comprises a prediction strategy indicating how a vertex in the at least one sub-mesh is decoded based on one or more vertices in the at least one sub-mesh.
17. 17 . The decoding method according to claim 16 , wherein the prediction strategy is a parallelogram prediction strategy.
18. 18 . The decoding method according to claim 16 , wherein the sub-mesh header further comprises a parameter indicating at least one of a singleway prediction mode and a multiway prediction mode.
19. 19 . The decoding method according to claim 18 , wherein the singleway prediction mode in which the vertex is encoded in accordance with the prediction strategy using at least one side of the sub-mesh header.
20. 20 . A method performed by at least one processor, the method comprising: processing a polygon mesh comprising a plurality of vertices defining a plurality of faces, wherein a mesh face type of the polygon mesh is determined; wherein the polygon mesh is divided into a plurality of sub-meshes; wherein a sub-mesh header for at least one sub-mesh from the plurality of sub-meshes is generated in accordance with at least the mesh face type of the polygon mesh; and wherein a bitstream comprising the polygon mesh and the sub-mesh header.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority from U.S. Provisional Application No. 63/715,508 filed on Nov. 1, 2024, and U.S. Provisional Application No. 63/720,140 filed on Nov. 13, 2024, the disclosure of each of which are incorporated herein by reference in their entirety. FIELD This disclosure is directed to a set of advanced video coding technologies. More specifically, the present disclosure is directed to high-level syntax for polygon compression. BACKGROUND A polygon mesh usually consists of several connected components (CCs), which may have different characteristics, so it's beneficial to divide CCs into different groups of CCs (named slices in this disclosure) based on their characteristics such that they can be compressed adaptively and efficiently. It may also be beneficial to group CCs into different sub-meshes based on their characteristics such that they can be compressed adaptively and efficiently. SUMMARY According to an aspect of the disclosure, a method of encoding performed by at least one processor, the method including: receiving a polygon mesh comprising a plurality of vertices defining a plurality of faces; determining a mesh face type of the polygon mesh; dividing the polygon mesh into a plurality of sub-meshes; generating a sub-mesh header for at least one sub-mesh from the plurality of sub-meshes in accordance with at least the mesh face type of the polygon mesh; and generating a bitstream comprising the polygon mesh and the sub-mesh header. According to an aspect of the disclosure, a decoding method performed by at least one processor, the method including: receiving a bitstream comprising a polygon mesh and a sub-mesh header, the polygon mesh divided into a plurality of sub-meshes; decoding at least one sub-mesh from the plurality of sub-meshes in accordance with the sub-mesh header, in which the sub-mesh header is generated based on a mesh face type of the polygon mesh. According to an aspect of the disclosure, a method performed by at least one processor includes: processing a polygon mesh comprising a plurality of vertices defining a plurality of faces, in which a mesh face type of the polygon mesh is determined; in which the polygon mesh is divided into a plurality of sub-meshes; in which a sub-mesh header for at least one sub-mesh from the plurality of sub-meshes is generated in accordance with at least the mesh face type of the polygon mesh; and in which a bitstream comprising the polygon mesh and the sub-mesh header. BRIEF DESCRIPTION OF THE DRAWINGS Further features, the nature, and various advantages of the disclosed subject matter will be more apparent from the following detailed description and the accompanying drawings in which: FIG. 1 is a schematic illustration of a block diagram of a communication system, in accordance with embodiments of the present disclosure. FIG. 2 is a schematic illustration of a block diagram of a streaming system, in accordance with embodiments of the present disclosure. FIG. 3 is a schematic illustration of an example mesh encoder, in accordance with embodiments of the present disclosure. FIG. 4 is a flowchart of an example process of encoding a polygon mesh, in accordance with embodiments of the present disclosure. FIG. 5 illustrates and example process for geometry encoding, in accordance with embodiments of the present disclosure. FIG. 6 illustrates an example process for how each slice is encoded, in accordance with embodiments of the present disclosure. FIGS. 7-9 illustrate lossless results of adding a geometry slice layer (no adaptive coding mode) vs. TM 5.0a with default cfgs, in accordance with embodiments of the present disclosure. FIGS. 10-12 illustrate lossless results of adding the geometry slice layer plus adaptive coding mode vs. TM 5.0 per-mesh cfgs, in accordance with embodiments of the present disclosure. FIGS. 13-15 illustrate additional lossless results of adding a geometry slice layer (no adaptive coding mode) vs. TM 5.0a with default cfgs, in accordance with embodiments of the present disclosure. FIGS. 16-18 illustrate additional lossless results of adding the geometry slice layer plus adaptive coding mode vs. TM 5.0 per-mesh cfgs, in accordance with embodiments of the present disclosure. FIGS. 19 and 20 illustrate results of Dual-degree-26c6346a vs. P01T0, in accordance with embodiments of the present disclosure. FIGS. 21 and 22 illustrate results of Parallelogram-prediction-a8fc726b vs. Dual-degree-26c6346a, in accordance with embodiments of the present disclosure. FIGS. 23 and 24 illustrate results of reflection-prediction-6f012e07 v. parallelogram-prediciton-a8fc726b, in accordance with embodiments of the present disclosure. FIG. 25 illustrates results specialUV-handing-9a10dee4 vs. reflection-prediction-6f012e07, in accordance with embodiments of the present disclosure. FIGS. 26-28 illustrate results of test model v1.0 vs. P01 (lossless), in accordance with embodiments of the present dis