IP Library › Granted Patent US 12701259

Granted Patent B2

US 12701259 · App. 18/747,222 · Granted Aug 4, 2026

Base mesh coding in mesh compression

Inventors: Jun Tian (Belle Mead, NJ); Xiaozhong Xu (State College, PA); Shan Liu (San Jose, CA)

Assignee: TENCENT AMERICA LLC

H04N19/50 G06T9/001 H04N19/124 H04N19/136 H04N19/167 H04N19/91

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Quick Facts

Patent No.: US 12701259
App. No.: 18/747,222
Granted: Aug 4, 2026
Kind: B2

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Abstract

In a method, a position prediction of a current vertex of a base mesh associated with a mesh in a current mesh frame is determined. An attribute prediction of the current vertex is determined. The base mesh includes a subset of a plurality of vertices of the mesh. A position prediction residue for the position prediction of the current vertex is quantized to generate a quantized position prediction residue. An attribute prediction residue for the attribute prediction of the current vertex is quantized to generate a quantized attribute prediction residue. The quantized position prediction residue for the position prediction of the current vertex is entropy coded in a bitstream. The quantized attribute prediction residue for the attribute prediction of the current vertex is entropy coded in the bitstream.

Claims (60)

1 . An apparatus for mesh decoding, comprising:

processing circuitry configured to:

receive a bitstream that includes base mesh information of a base mesh, the base mesh including a subset of a plurality of vertices of a mesh in a current mesh frame;

determine (i) a position prediction of a current vertex of the base mesh and (ii) an attribute prediction of the current vertex;

determine (i) a position prediction residue for the position prediction of the current vertex based on a first quantization step value and (ii) an attribute prediction residue for the attribute prediction of the current vertex of the base mesh based on a second quantization step value, the first quantization step value being determined based on the second quantization step value or the second quantization step value being determined based on the first quantization step value; and

reconstruct (i) a position of the current vertex of the base mesh based on the position prediction and the position prediction residue and (ii) an attribute of the current vertex of the base mesh based on the attribute prediction and the attribute prediction residue.

2 . The apparatus of claim 1 , wherein:

the attribute prediction is a two-dimensional (2D) texture coordinate prediction, and

the processing circuitry is configured to:

determine the position prediction of the current vertex based on one or more coded vertices according to a multi-parallelogram prediction; and

determine the 2D texture coordinate prediction of the current vertex based on the one or more coded vertices according to a stretch prediction algorithm.

3 . The apparatus of claim 1 , wherein:

the attribute prediction is a two-dimensional (2D) texture coordinate prediction and the attribute prediction residue is a 2D texture coordinate prediction residue, and

the processing circuitry is configured to:

determine a quantized position prediction residue for the position prediction of the current vertex based on a first entropy decoding;

dequantize the quantized position prediction residue for the position prediction of the current vertex to determine the position prediction residue based on the first quantization step value;

determine a quantized 2D texture coordinate prediction residue for the 2D texture coordinate prediction for the current vertex based on a second entropy decoding; and

dequantize the quantized 2D texture coordinate prediction residue for the 2D texture coordinate prediction of the current vertex to determine the 2D texture coordinate prediction residue based on the second quantization step value.

4 . The apparatus of claim 3 , wherein:

the second quantization step value is determined based on the first quantization step value,

a log 2 of a denominator of the first quantization step value is in a range between 0 and 7,

the second quantization step value is one of 1, 2, 4, 8, 16, 32, 64, and 128, and

the first quantization step value is one of 1, 2, 4, 8, 16, 32, 64, and 128.

5 . The apparatus of claim 3 , wherein the second quantization step value is equal to a multiple of the first quantization step value.

6 . The apparatus of claim 3 , wherein the second quantization step value is equal to one of a linear function and a monotonically non-decreasing function of the first quantization step value.

7 . The apparatus of claim 3 , wherein the second quantization step value is equal to a monotonically non-decreasing function of a quantization error associated with the position prediction of the current vertex, the quantization error being a difference between the quantized position prediction residue and an unquantized position prediction residue for the current vertex.

8 . The apparatus of claim 3 , wherein the first quantization step value is determined based on the second quantization step value.

9 . The apparatus of claim 3 , wherein the first quantization step value is equal to a multiple of the second quantization step value.

10 . The apparatus of claim 3 , wherein the first quantization step value is equal to one of a linear function and a monotonically non-decreasing function of the second quantization step value.

11 . The apparatus of claim 3 , wherein the first quantization step value is equal to a monotonically non-decreasing function of a quantization error associated with the 2D texture coordinate prediction of the current vertex, the quantization error being a difference between the quantized 2D texture coordinate prediction residue and an unquantized 2D texture coordinate prediction residue for the current vertex.

12 . A method of video encoding, comprising:

determining (i) a position prediction of a current vertex of a base mesh associated with a mesh in a current mesh frame and (ii) an attribute prediction of the current vertex, the base mesh including a subset of a plurality of vertices of the mesh;

quantizing (i) a position prediction residue for the position prediction of the current vertex to generate a quantized position prediction residue based on a first quantization step value and (ii) an attribute prediction residue for the attribute prediction of the current vertex to generate a quantized attribute prediction residue based on a second quantization step value, the first quantization step value being determined based on the second quantization step value or the second quantization step value being determined based on the first quantization step value; and

entropy coding (i) the quantized position prediction residue for the position prediction of the current vertex and (ii) the quantized attribute prediction residue for the attribute prediction of the current vertex in a bitstream.

13 . The method of claim 12 , wherein:

the attribute prediction residue is a two-dimensional (2D) texture coordinate prediction residue, the attribute prediction is a 2D texture coordinate prediction, and

the method further comprises:

dequantizing (i) the quantized position prediction residue for the position prediction of the current vertex to obtain the position prediction residue of the position prediction of the current vertex and (ii) the quantized 2D texture coordinate prediction residue for the 2D texture coordinate prediction of the current vertex to obtain the 2D texture coordinate prediction residue of the current vertex; and

reconstructing (i) a position of the current vertex based on the position prediction and the position prediction residue and (ii) a 2D texture coordinate for the current vertex based on the 2D texture coordinate prediction and the 2D texture coordinate prediction residue.

14 . The method of claim 12 , wherein:

the attribute prediction residue is a two-dimensional (2D) texture coordinate prediction residue, the attribute prediction is a 2D texture coordinate prediction;

the determining the position prediction residue includes determining the position prediction of the current vertex based on one or more coded vertices according to a multi-parallelogram prediction; and

the determining the 2D texture coordinate prediction residue includes determining the 2D texture coordinate prediction of the current vertex based on the one or more coded vertices according to a stretch prediction algorithm.

15 . The method of claim 12 , wherein:

the attribute prediction residue is a two-dimensional (2D) texture coordinate prediction residue, the attribute prediction is a 2D texture coordinate prediction;

the quantizing the position prediction residue for the position prediction of the current vertex includes quantizing the position prediction residue for the position prediction of the current vertex based on the first quantization step value; and

the quantizing the 2D texture coordinate prediction residue for the 2D texture coordinate prediction of the current vertex includes quantizing the 2D texture coordinate prediction residue for the 2D texture coordinate prediction of the current vertex based on the second quantization step value.

16 . The method of claim 15 , wherein:

the second quantization step value is determined based on the first quantization step value,

a log 2 of a denominator of the first quantization step value is in a range between 0 and 7,

the second quantization step value is one of 1, 2, 4, 8, 16, 32, 64, and 128, and

the first quantization step value is one of 1, 2, 4, 8, 16, 32, 64, and 128.

17 . The method of claim 15 , wherein the second quantization step value is equal to a multiple of the first quantization step value.

18 . The method of claim 15 , wherein the second quantization step value is equal to one of a linear function and a monotonically non-decreasing function of the first quantization step value.

19 . The method of claim 15 , wherein the second quantization step value is equal to a monotonically non-decreasing function of a quantization error associated with the position prediction of the current vertex, the quantization error being a difference between the quantized position prediction residue and an unquantized position prediction residue for the current vertex.

20 . A non-transitory computer-readable storage medium storing instructions which when executed by a processor cause the processor to perform an encoding method comprising:

transmitting the bitstream.