US-20260129206-A1 - SIGNALING DUAL DEGREE INFORMATION FOR POLYGON MESH COMPRESSION

US20260129206A1US 20260129206 A1US20260129206 A1US 20260129206A1US-20260129206-A1

Abstract

A method of encoding includes receiving a polygon mesh comprising a plurality of vertices defining a plurality of faces; determining, for at least a portion of the polygon mesh, a mesh face type; determining, using the mesh face type, a first parameter corresponding to a face degree mode; encoding, using the mesh face type, the first parameter corresponding to the face degree mode; and generating a bitstream comprising the polygon mesh encoded in accordance with a dual degree process, the mesh face type, and the first parameter.

Inventors

Chao Huang
Shan Liu

Assignees

Tencent America LLC

Dates

Publication Date: 20260507
Application Date: 20250818

Claims (20)

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, for at least a portion of the polygon mesh, a mesh face type; determining, using the mesh face type, a first parameter corresponding to a face degree mode; encoding, using the mesh face type, the first parameter corresponding to the face degree mode; and generating a bitstream comprising the polygon mesh encoded in accordance with a dual degree process, the mesh face type, and the first parameter.
2 . The method according to claim 1 , wherein when the mesh face type indicates that the portion of the polygon mesh comprises both triangle and quad faces, the first parameter corresponding to the face degree mode is encoded using one bit, and wherein when the mesh face type indicates that the portion of the polygon mesh comprises polygon faces having more than four sides, the first parameter corresponding to the face degree mode is encoded using more than one bit.
3 . The method according to claim 1 , further comprising: determining, using the mesh face type, a second parameter corresponding to a difference between the face degree mode and a minimum face degree and a third parameter corresponding to a difference between a maximum face degree and the face degree mode; and encoding, using the mesh face type, the second parameter and the third parameter, wherein the bitstream further comprises the second parameter and the third parameter.
4 . The method according to claim 2 , wherein when the mesh face type indicates that the portion of the polygon mesh comprises both triangle and quad faces, the second parameter and the third parameter are encoded using one bit, and wherein when the mesh face type indicates that the portion of the polygon mesh comprises polygon faces having more than four sides, the second parameter and the third parameter are encoded using more than one bit.
5 . The method according to claim 1 , wherein the mesh face type is coded using 2 bits indicating the mesh face type as one of a triangle, quadrilateral, tri-quad, and polygon.
6 . The method according to claim 1 , wherein the mesh face type is encoded using a variable number of bits.
7 . The method according to claim 1 , wherein when the portion of the mesh comprises two mesh face types, a first mesh face type is encoded using a variable number of bits and a second mesh face type is encoded using a variable number of bits.
8 . The method according to claim 1 , further comprising: determining, for at least the portion of the polygon mesh, a vertex degree mode predictor using the face degree mode.
9 . The method according to claim 8 , further comprising: determining, for at least the portion of the polygon mesh, a vertex degree mode; determining, for at least the portion of the polygon mesh, a vertex degree mode residual that is a difference between the vertex degree mode and the vertex degree mode predictor, wherein the bitstream further comprises a vertex degree mode residual.
10 . The method according to claim 9 , wherein the vertex degree mode predictor is 6 when the face degree mode is 3, wherein the vertex degree mode predictor is 4 when the face degree mode is 4, and wherein the vertex degree mode predictor is 0 when the face degree mode is 0.
11 . The method according to claim 10 , wherein the vertex degree mode predictor is 3 when the face degree mode is not 0, 3, and 4.
12 . The method according to claim 9 , wherein the vertex degree mode is encoded using two bits indicating the vertex degree mode being a value that is 6, 4, 3 or 1.
13 . The method according to claim 1 , wherein the bitstream further comprises a dummy degree face mode.
14 . A method of decoding performed by at least one processor, the method comprises: receiving a bitstream comprising a polygon mesh, in accordance with a dual degree process, a mesh face type for at least a portion of the polygon mesh, and a first parameter corresponding to the face degree mode for at least a portion of the mesh; and decoding, using the mesh face type, the face degree mode; decoding the portion of the polygon mesh using the mesh face type and the face degree mode.
15 . The method according to claim 14 , wherein when the mesh face type indicates that the portion of the polygon mesh comprises both triangle and quad faces, the first parameter corresponding to the face degree mode is encoded using one bit, and wherein when the mesh face type indicates that the portion of the polygon mesh comprises polygon faces having more than four sides, the first parameter corresponding to the face degree mode is encoded using more than one bit.
16 . The method according to claim 14 , wherein the bitstream further comprises a second parameter corresponding to a difference between the face degree mode and a minimum face degree and a third parameter corresponding to a difference between a maximum face degree and the face degree mode.
17 . The method according to claim 16 , wherein when the mesh face type indicates that the portion of the polygon mesh comprises both triangle and quad faces, the second parameter and the third parameter are encoded using one bit, and wherein when the mesh face type indicates that the portion of the polygon mesh comprises polygon faces having more than four sides, the second parameter and the third parameter are encoded using more than one bit.
18 . The method according to claim 14 , wherein the mesh face type is coded using 2 bits indicating the mesh face type as one of a triangle, quadrilateral, tri-quad, and polygon.
19 . The method according to claim 14 , wherein the mesh face type is encoded using a variable number of bits.
20 . A method of encoding a polygon mesh, the method comprising: generating a bitstream comprising the polygon mesh that comprises a plurality of vertices defining a plurality of faces, wherein for at least a portion of the polygon mesh, a mesh face type is determined, wherein using the mesh face type, a first parameter corresponding to a face degree mode is determined; wherein using the mesh face type, the first parameter corresponding to the face degree mode is encoded, and wherein the bitstream comprises the polygon mesh encoded in accordance with a dual degree process, the mesh face type, and the face degree mode is generated; and transmitting the generated bitstream.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority from U.S. Provisional Application No. 63/715,482 filed on Nov. 1, 2024, and U.S. Provisional Application No. 63/720,131 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 signaling dual degree information for polygon mesh compression. BACKGROUND The connectivity of a polygon mesh can be coded with either the polygon-fan method or the dual-degree method, both of which require the face and vertex information of the mesh, such as the mesh face type, vertex degree mode, face degree mode. The vertex degree of a vertex is the number of incident faces, and the face degree of a face is the number of incident vertices. The vertex degree mode and face degree mode of a mesh are the most frequent vertex degree, the most frequent face degree in the mesh, respectively. To code the connectivity of a polygon mesh, we can employ the dual-degree method, which uses the certain geometry information of the mesh, such as the vertex degree mode, face degree mode, dummy face degree mode, maximum face degree, minimum face degree, etc. The vertex degree of a vertex is the number of incident faces, and the face degree of a face is the number of incident vertices. The vertex degree mode, face degree mode and dummy face degree mode of a mesh are the most frequent vertex degree, the most frequent face degree and the most frequent dummy face degree in the mesh, respectively. SUMMARY According to embodiments of the present disclosure, 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, for at least a portion of the polygon mesh, a mesh face type; determining, using the mesh face type, a first parameter corresponding to a face degree mode; encoding, using the mesh face type, the first parameter corresponding to the face degree mode; and generating a bitstream comprising the polygon mesh encoded in accordance with a dual degree process, the mesh face type, and the first parameter. According to embodiments of the present disclosure, a method of decoding includes receiving a bitstream comprising a polygon mesh, in accordance with a dual degree process, a mesh face type for at least a portion of the polygon mesh, and a first parameter corresponding to the face degree mode for at least a portion of the mesh; and decoding, using the mesh face type, the face degree mode; decoding the portion of the polygon mesh using the mesh face type and the face degree mode. According to embodiments of the present disclosure, a method of encoding a polygon mesh includes: generating a bitstream comprising the polygon mesh that comprises a plurality of vertices defining a plurality of faces, in which for at least a portion of the polygon mesh, a mesh face type is determined, in which using the mesh face type, a first parameter corresponding to a face degree mode is determined; in which using the mesh face type, the first parameter corresponding to the face degree mode is encoded, and in which the bitstream comprises the polygon mesh encoded in accordance with a dual degree process, the mesh face type, and the face degree mode is generated; and transmitting the generated bitstream. 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 for encoding a 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