CN119229054A

CN119229054A - Three-dimensional grid encoding method, three-dimensional grid decoding method, device and equipment

Info

Publication number: CN119229054A
Application number: CN202310795676.3A
Authority: CN
Inventors: 邹文杰; 张伟; 杨付正; 吕卓逸
Original assignee: Vivo Mobile Communication Co Ltd
Current assignee: Vivo Mobile Communication Co Ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2024-12-31
Also published as: WO2025002017A1

Abstract

The application discloses a three-dimensional grid coding method, a three-dimensional grid decoding method, a device and equipment, which belong to the technical field of encoding and decoding, and the three-dimensional grid coding method of the embodiment of the application comprises the steps of performing color space format conversion on a texture map of a first color space format of a three-dimensional grid to obtain a texture map of a second color space format; and carrying out coding processing on the texture map in the second color space format to obtain a first texture map code stream.

Description

Three-dimensional grid coding method, three-dimensional grid decoding method, device and equipment

Technical Field

The application belongs to the technical field of encoding and decoding, and particularly relates to a three-dimensional grid encoding method, a three-dimensional grid decoding device and equipment.

Background

With the rapid development of multimedia technology, three-dimensional models become a new generation of digital media following audio, images, and video. Three-dimensional grids and point clouds are two commonly used three-dimensional model representations. Compared with traditional multimedia such as images and videos, the three-dimensional grid model has the characteristics of stronger interactivity and reality, and has wider application range.

In the related art, when the texture map of the three-dimensional grid is encoded, the texture map of the BGR444 format is directly encoded, and the flexibility of encoding the texture map of the three-dimensional grid is poor.

Disclosure of Invention

The embodiment of the application provides a three-dimensional grid coding method, a three-dimensional grid decoding method, a device and equipment, which can solve the problem of poor flexibility in coding texture maps of three-dimensional grids.

In a first aspect, a three-dimensional grid coding method is provided, which is executed by a coding end and includes:

Performing color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain a texture map in the second color space format;

and carrying out coding processing on the texture map in the second color space format to obtain a first texture map code stream.

In a second aspect, a three-dimensional trellis decoding method is provided, performed by a decoding end, including:

decoding a first texture map code stream in the code stream corresponding to the three-dimensional grid to obtain a texture map in a second color space format;

Performing color space format conversion on the texture map in the second color space format to obtain a texture map in the first color space format;

and carrying out grid reconstruction processing based on the texture map in the first color space format to obtain a reconstructed three-dimensional grid.

In a third aspect, there is provided a three-dimensional trellis encoding device, the device comprising:

The conversion module is used for carrying out color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain a texture map in the second color space format;

And the first coding module is used for coding the texture map in the second color space format to obtain a first texture map code stream.

In a fourth aspect, there is provided a three-dimensional trellis decoding device, the device comprising:

the first decoding module is used for decoding a first texture map code stream in the code stream corresponding to the three-dimensional grid to obtain a texture map in a second color space format;

The conversion module is used for carrying out color space format conversion on the texture map in the second color space format to obtain a texture map in the first color space format;

And the reconstruction module is used for carrying out grid reconstruction processing based on the texture map in the first color space format to obtain a reconstructed three-dimensional grid.

In a fifth aspect, there is provided an electronic device comprising a processor, a memory and a program or instruction stored on the memory and executable on the processor, the program or instruction when executed by the processor implementing the steps of the method according to the first aspect, or the program or instruction when executed by the processor implementing the steps of the method according to the second aspect.

In a sixth aspect, an electronic device is provided, including a processor and a communication interface, where the processor is configured to perform color space format conversion on a texture map in a first color space format of a three-dimensional grid to obtain a texture map in a second color space format, and perform encoding processing on the texture map in the second color space format to obtain a first texture map code stream.

In a seventh aspect, an electronic device is provided, including a processor and a communication interface, where the processor is configured to decode a first texture map code stream in a code stream corresponding to a three-dimensional grid to obtain a texture map in a second color space format, perform color space format conversion on the texture map in the second color space format to obtain a texture map in the first color space format, and perform grid reconstruction processing based on the texture map in the first color space format to obtain a reconstructed three-dimensional grid.

In an eighth aspect, there is provided a readable storage medium having stored thereon a program or instructions which when executed by a processor, performs the steps of the three-dimensional trellis encoding method of the first aspect, or which when executed by a processor, performs the steps of the three-dimensional trellis decoding method of the second aspect.

In a ninth aspect, there is provided a chip comprising a processor and a communication interface, the communication interface and the processor being coupled, the processor being for running a program or instructions, implementing the steps of the method as described in the first aspect, or implementing the steps of the method as described in the second aspect.

In a tenth aspect, a computer program/program product is provided, stored in a non-volatile storage medium, the program/program product being executed by at least one processor to implement the steps of the method as described in the first aspect, or to implement the steps of the method as described in the second aspect.

In the embodiment of the application, the texture map in the first color space format of the three-dimensional grid is subjected to color space format conversion to obtain the texture map in the second color space format, and the texture map in the second color space format is subjected to coding processing to obtain a first texture map code stream. In this way, in the three-dimensional grid coding process, the color space format conversion is carried out on the texture map of the three-dimensional grid, so that the texture map of the three-dimensional grid is supported to be converted into texture maps with other color space formats for coding, and the flexibility of the texture map coding of the three-dimensional grid can be improved.

Drawings

FIG. 1 is a schematic diagram of five modes of Edgebreaker in the related art;

FIG. 2 is a diagram of a vertex traversal process and an operation mode string according to the related art Edgebreaker;

FIG. 3 is a flow chart of a three-dimensional trellis encoding method provided by an embodiment of the present application;

FIG. 4 is a flow chart of a three-dimensional trellis decoding method provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a three-dimensional trellis encoding framework provided by an embodiment of the present application;

FIG. 6 is a schematic diagram of a three-dimensional trellis decoding framework provided by an embodiment of the present application;

FIG. 7 is a schematic illustration of a manifold mesh provided by an embodiment of the present application;

FIG. 8 is a schematic illustration of a Corner relationship provided by an embodiment of the present application;

FIG. 9 is a diagram of a grid traversal provided by an embodiment of the application;

FIG. 10 is a schematic view of a three-dimensional grid provided by an embodiment of the present application;

FIG. 11 is a schematic diagram of UV coordinate prediction based on three-dimensional to two-dimensional projection according to an embodiment of the present application;

FIG. 12 is a schematic diagram of a three-dimensional trellis encoding device provided by an embodiment of the present application;

fig. 13 is a schematic structural diagram of a three-dimensional trellis decoding device provided by an embodiment of the present application;

Fig. 14 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 15 is a schematic structural diagram of a terminal according to an embodiment of the present application.

Detailed Description

The technical solutions of the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which are derived by a person skilled in the art based on the embodiments of the application, fall within the scope of protection of the application.

The terms "first," "second," and the like, herein, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application are capable of operation in sequences other than those illustrated or otherwise described herein, and that the "first" and "second" distinguishing between objects generally are not limited in number to the extent that the first object may, for example, be one or more. Furthermore, the "or" in the present application means at least one of the connected objects. For example, "A or B" encompasses three schemes, namely scheme one including A and excluding B, scheme two including B and excluding A, scheme three including both A and B. The character "/" generally indicates that the context-dependent object is an "or" relationship.

The term "indication" according to the application may be either a direct indication (or an explicit indication) or an indirect indication (or an implicit indication). The direct indication may be understood that the sender explicitly informs the specific information of the receiver, the operation to be executed, the request result, and the like in the sent indication, and the indirect indication may be understood that the receiver determines the corresponding information according to the indication sent by the sender, or determines the operation to be executed, the request result, and the like according to the determination result.

The codec end corresponding to the codec method in the embodiment of the present application may be a terminal, which may also be referred to as a terminal device or a User Equipment (UE), and the terminal may be a Mobile phone, a tablet (Tablet Personal Computer), a Laptop (Laptop Computer) or a terminal-side device called a notebook, a Personal digital assistant (Personal DIGITAL ASSISTANT, PDA), a palm Computer, a netbook, an ultra-Mobile Personal Computer, a UMPC, a Mobile internet device (Mobile INTERNET DEVICE, MID), an augmented reality (augmented reality, AR)/Virtual Reality (VR) device, a robot, a wearable device (Wearable Device) or a vehicle-mounted device (Vehicle User Equipment, VUE), a pedestrian terminal (PEDESTRIAN USER EQUIPMENT, PUE), and the wearable device includes a smart watch, a bracelet, an earphone, a glasses, and the like. It should be noted that, the embodiment of the present application is not limited to a specific type of terminal.

For ease of understanding, some of the following descriptions are directed to embodiments of the present application:

1. three-dimensional grid

In recent years, with rapid development of multimedia technology, related research results are rapidly industrialized, and become an essential component in people's life. The three-dimensional model becomes a new generation of digital media following audio, images, video. Three-dimensional grids and point clouds are two commonly used three-dimensional model representations. Compared with traditional multimedia such as images and videos, the three-dimensional grid model has the characteristics of stronger interactivity and reality, so that the three-dimensional grid model is more and more widely applied to various fields such as business, manufacturing industry, construction industry, education, medicine, entertainment, art, military and the like.

With the increasing demands of people on the visual effect of the three-dimensional grid model and the emerging of many more mature three-dimensional scanning technologies and three-dimensional modeling software, the data size and complexity of the three-dimensional grid model obtained by the three-dimensional scanning device or the three-dimensional modeling software are also dramatically increased. Therefore, how to efficiently compress three-dimensional mesh data is a key to achieve convenient transmission, storage, and processing of three-dimensional mesh data.

A three-dimensional grid often contains three main information, namely topology information, geometric information and attribute information. Topology information, also called connectivity relation information, is used to describe the connection relation between the vertices in the mesh and the elements such as the face sheets, the geometry information is the three-dimensional coordinates of all the vertices in the mesh, and the attribute information records other information attached to the mesh, such as normal vectors, texture coordinates, colors, and the like. The compression of three-dimensional grid data is often performed on the three kinds of information according to the data characteristics of the three kinds of information. In addition, for a three-dimensional grid with texture maps, the texture maps need to be compressed.

Draco is a library for compressing and decompressing 3D geometric meshes and point clouds, aiming at improving the storage and transmission of 3D graphics, greatly accelerating the encoding, transmission and decoding of 3D data. Draco support compression of three-dimensional mesh geometry information, connection information, and attribute information. Draco support a lossy mode and a near lossless mode. In addition, edgebreaker method used when Draco codes connection relations is one of the most efficient methods for coding three-dimensional grid connection information at present.

Edgebreaker requires that the mesh to be encoded be manifold, and for meshes where non-manifold structures exist, draco must be split into manifolds to be encoded correctly. However, draco does not combine the split structure at the decoding end, which allows the grid output from the decoding end to have more split points than the original grid input from the encoding end. This results in Draco not being able to losslessly encode such grids that have non-manifold structures.

The international standards organization moving picture experts group (Moving Picture Expert Group, MPEG) for Video image neighborhood is developing new dynamic three-dimensional grid compression standards based on dynamic three-dimensional grid compression of Video (Video-based DYNAMIC MESH coding, V-DMC or VDMC), currently also opting to employ Edgebreaker-based schemes and temporarily multiplexing Draco codecs when encoding static three-dimensional grids. Meanwhile, MPEG is also attempting to implement a Edgebreaker-based three-dimensional mesh codec provided by MPEG to implement compression of three-dimensional mesh geometry information, connection information, and attribute information. Since Edgebreaker requires that the mesh to be encoded is a manifold structure, there is a possibility in the presently proposed scheme to split the three-dimensional mesh of the non-manifold structure into manifold structures for encoding. Thus, in lossless mode, the three-dimensional mesh codec implementation provided by MPEG based Edgebreaker records and encodes the repetition point information generated by the non-manifold splitting, and adds an identifier to each vertex of the split manifold mesh to determine whether it is a repetition point generated by the non-manifold splitting, thereby restoring the non-manifold structure of the original three-dimensional mesh at the decoding end according to the identifier and the repetition point information generated by the non-manifold splitting to implement lossless encoding of the three-dimensional mesh.

The three-dimensional mesh compression tool based on Edgebreaker currently provided by MPEG encodes and stores connection information, geometric information, and attribute information (e.g., UV coordinates) of a three-dimensional mesh, respectively. The UV coordinates are two-dimensional coordinates, the horizontal direction is U, and the vertical direction is V. The key module, namely the module for encoding the connection information, uses Edgebreaker algorithm. Taking the attribute information as UV coordinates as an example, the geometric information and the UV coordinates are encoded by adopting a conventional compression method, namely, quantization, predictive compression (for example, parallelogram prediction) and entropy encoding of the data. Since the tool adopts a connection relation driven coding method, the coding of the geometric information and the UV coordinates follows the coding sequence of the connection information. In this way, the vertex sequence of the connection relation code is implicit in the vertex sequence of the geometric information to avoid separately transmitting the vertex sequence of the connection relation code, thereby saving the bit overhead of the part.

2、Edgebreaker

The Edgebreaker (which can be simply called EB) method is a three-dimensional grid connection relation coding method which has the advantages of good compression performance, convenient realization, capability of giving an upper limit of a compression ratio and the like. The Edgebreaker method only describes a compression method of the three-dimensional grid connection information, and the compression of the three-dimensional grid can be realized through geometric information compression, entropy coding and the like.

The Edgebreaker encoding technique can achieve 2 bits per triangle or less of compression efficiency on triangle meshes that are co-embryo with spheres. The encoding algorithm accesses each triangle of the mesh in depth-first order using five different modes (referred to as C, L, E, R and S). And marking each triangle according to the mode of the triangle, and generating CLERS character strings to obtain compact representation of the grid connection relation.

Five modes of the Edgebreaker method are shown in figure 1. The Edgebreaker method separates the mesh into a traversed portion and a non-traversed portion, the boundary of the two portions being referred to as the active boundary. In the encoding process of Edgebreaker, the triangle to be traversed is accessed through the active edge on the active boundary, and which mode is used is selected according to the relation between the active edge and the triangle in which it is located. The other vertex in the triangle where the active edge is located is referred to as the third vertex. If the third vertex is not on the active boundary, then the current triangle is marked as C-mode. If the third vertex is on the active boundary and, in a counter-clockwise order, is next to the currently active edge vertex, then the current triangle is marked as R-mode. If the third vertex is on the active boundary and, in a counter-clockwise order, is the last of the currently active edge vertices, then the current triangle is marked as L-mode. If the third vertex is on the active boundary and in a counter-clockwise order is both the last vertex of the currently active edge vertex and the next vertex of the currently active edge, then the current triangle is marked as E-mode. If the third vertex is on the active boundary, but in a counter-clockwise order, neither the last vertex of the currently active edge vertex nor the next vertex of the currently active edge, then the current triangle is marked as S-mode.

After each marking of a triangle, the active boundary is updated and the next active edge is selected according to certain rules. After traversing all triangles, entropy coding is carried out on the obtained CLERS character strings, so that higher compression efficiency can be obtained.

Fig. 2 shows a schematic diagram of a two-dimensional grid encoded using EBs. The final entropy encoded mode codeword is CCRRSLCRSERRELCRRRCRRRE according to the EB encoding rules.

Since the five modes of the Edgebreaker method cannot handle non-manifold grids, the grid must be converted to a manifold grid before the Edgebreaker method can be used.

In the related art, when the texture map of the three-dimensional grid is encoded, the texture map in the BGR444 format is directly encoded, so that the encoding and decoding efficiency of the three-dimensional grid is low.

The three-dimensional grid coding method, the three-dimensional grid decoding device and the equipment provided by the embodiment of the application are described in detail below through some embodiments and application scenes thereof with reference to the attached drawings.

Referring to fig. 3, fig. 3 is a flowchart of a three-dimensional grid coding method according to an embodiment of the present application, which may be applied to a coding end, as shown in fig. 3, and the three-dimensional grid coding method includes the following steps:

step 101, performing color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain a texture map in the second color space format.

Wherein the first color space format may be an original color space format of a texture map of the three-dimensional grid. The first color space format may be an RGB color space format, for example, the first color space format may be BGR444, BGR555, RGB555, or RGB 565, or the like, or the first color space format may be a YUV color space format, or the first color space format may be a CMY color space format, or the first color space format may be a CMYK color space format, or the first color space format may be an HSV color space format, or the like, and the present embodiment is not limited to the first color space format. RGB refers to red (red), green (green) and blue (blue). CMY refers to Cyan (Cyan), magenta (Magenta), and Yellow (Yellow). Y in YUV represents Luminance (Luminance), and UV represents chromaticity (Chrominance) and density (Chroma), respectively. CMYK refers to Cyan (Cyan), magenta (Magenta), yellow (Yellow), and black (black). HSV refers to the hue-saturation-value (hue-saturation-value).

In addition, the second color space format may be a color space format after the color space format conversion. The second color space format and the first color space format are different color space formats. The second color space format may be a YUV color space format, for example, the second color space format may be YUV444, YUV420, YUV422, or the like, or the second color space format may be an RGB color space format, the second color space format may also be an HSV color space format, or the second color space format may also be a CMY color space format, or the second color space format may also be a Lab color space format, or the like, which is not limited in this embodiment. Where L in Lab is the luminance and a and b are the two color channels.

In one embodiment, the second color space format and the first color space format are different color space formats of a different color space, or the second color space format and the first color space format are different formats of a same color space.

It should be noted that different color space format conversions may be performed for different application scenarios. To improve the coding efficiency, the amount of information related to the color space of the texture map in the second color space format may be smaller than the amount of information related to the texture map in the first color space format. For example, the texture map in the second color space format is a texture map obtained by removing certain redundant information from the texture map in the first color space format, or the texture map in the second color space format is a texture map obtained by removing correlation between color components from the texture map in the first color space format.

It should be noted that, the performing color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain the texture map in the second color space format may be performing lossless color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain the texture map in the second color space format.

And 102, carrying out coding processing on the texture map in the second color space format to obtain a first texture map code stream.

Optionally, performing color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain a texture map in the second color space format, including:

and under the condition that the color space format conversion is carried out on the texture map of the three-dimensional grid, carrying out the color space format conversion on the texture map of the first color space format of the three-dimensional grid, and obtaining the texture map of the second color space format.

The encoding end can determine whether to perform color space format conversion on the texture map of the three-dimensional grid. The encoding end can determine whether to perform color space format conversion on the texture map of the three-dimensional grid based on different encoding requirements. For example, in the case where higher codec efficiency is required, it may be determined to perform color space format conversion on the texture map of the three-dimensional mesh.

In this embodiment, when it is determined that the color space format conversion is performed on the texture map of the three-dimensional grid, the color space format conversion is performed on the texture map of the first color space format of the three-dimensional grid to obtain the texture map of the second color space format, so that by determining whether to perform the color space format conversion on the texture map of the three-dimensional grid, the encoding end can be supported to selectively perform the color space format conversion on the texture map, and the flexibility of encoding the texture map in the three-dimensional grid encoding process can be improved.

Optionally, the method further comprises:

And under the condition that the texture map of the three-dimensional grid is not subjected to color space format conversion, encoding processing is carried out on the texture map of the first color space format, and a second texture map code stream is obtained.

The encoding end can determine whether to perform color space format conversion on the texture map of the three-dimensional grid. The encoding end can determine whether to perform color space format conversion on the texture map of the three-dimensional grid based on different encoding requirements. For example, in a scene where the requirements on the coding efficiency are not high, it may be determined that the texture map of the three-dimensional mesh is not subjected to color space format conversion.

In this embodiment, under the condition that it is determined that the color space format conversion is not performed on the texture map of the three-dimensional grid, the texture map in the first color space format is subjected to coding processing to obtain the second texture map code stream, so that by judging whether the color space format conversion is performed on the texture map of the three-dimensional grid, the coding end can be supported to selectively not perform the color space format conversion on the texture map, and the flexibility of coding the texture map in the three-dimensional grid coding process can be further improved.

Optionally, the code stream corresponding to the three-dimensional grid includes a coding result of first indication information, where the first indication information is used to indicate whether the coding end performs color space format conversion on the texture map of the three-dimensional grid;

Wherein, under the condition that the first indication information indicates the encoding end to perform color space format conversion on the texture map of the three-dimensional grid, the code stream corresponding to the three-dimensional grid also comprises the first texture map code stream, or

And under the condition that the first indication information indicates that the encoding end does not perform color space format conversion on the texture map of the three-dimensional grid, the code stream corresponding to the three-dimensional grid further comprises a second texture map code stream.

The first indication information is "0", and indicates that the encoding end does not perform color space format conversion on the texture map of the three-dimensional grid, otherwise, the first indication information indicates that the encoding end performs color space format conversion on the texture map of the three-dimensional grid.

It should be noted that, when the first indication information indicates that the color space format conversion is performed on the texture map of the three-dimensional grid, the first indication information may also be used to indicate a conversion type of the texture map of the three-dimensional grid from the first color space format to the second color space format, so that the decoding end may determine, according to the first indication information, what type of color space format conversion is performed by the encoding end, so that the decoding end may perform the inverse conversion of the corresponding color space format to recover the original texture map.

In this embodiment, the code stream corresponding to the three-dimensional grid includes the first texture map code stream or the second texture map code stream, and the code stream corresponding to the three-dimensional grid further includes a coding result of first indication information, where the first indication information is used to indicate whether the coding end performs color space format conversion on the texture map of the three-dimensional grid, so that the first indication information indicates whether the coding end performs color space format conversion on the texture map of the three-dimensional grid, and the decoding end can determine whether to perform color space format conversion on the decoded texture map through the first indication information, so that the decoding end is convenient to reconstruct the three-dimensional grid.

Optionally, in a case where the first indication information indicates that the texture map of the three-dimensional grid is subjected to color space format conversion, the first indication information is further used for indicating a conversion type of the texture map of the three-dimensional grid from the first color space format to the second color space format.

The first indication information may be used to indicate that the texture map of the three-dimensional grid is converted from the first color space format to the second color space format at the encoding end. In one embodiment, the first indication information may be a value in a preset list, where different values in the preset list represent different conversion types of the color space format. The method includes the steps of setting a first indication information of '0', indicating that a coding end does not perform color space format conversion on a texture map of a three-dimensional grid, setting a first indication information of '1', indicating that the texture map of the three-dimensional grid is converted from BGR444 format of RGB color space to YUV444 format of YUV color space at the coding end, setting a first indication information of '2', indicating that the texture map of the three-dimensional grid is converted from BGR444 format of RGB color space to RGB444 format of RGB color space at the coding end, setting a first indication information of '3', indicating that the texture map of the three-dimensional grid is converted from BGR444 format of RGB color space to YUV420 format of YUV color space at the coding end, setting a first indication information of '4', indicating that the texture map of the three-dimensional grid is converted from BGR444 format of RGB color space to YUV422 format of YUV color space at the coding end, setting a first indication information of '5', and the like.

In this embodiment, when the first indication information indicates that the color space format conversion is performed on the texture map of the three-dimensional grid, the first indication information is further used to indicate a conversion type of the texture map of the three-dimensional grid from the first color space format to the second color space format, so that the decoding end can determine, through the first indication information, what type of color space format conversion is performed by the encoding end, and it is convenient for the decoding end to perform the inverse conversion of the corresponding color space format to recover the original texture map.

Optionally, the amount of information related to the color space of the texture map in the second color space format is smaller than the amount of information related to the color space of the texture map in the first color space format.

The texture map in the second color space format may be a texture map obtained by removing certain redundant information from the texture map in the first color space format, or the texture map in the second color space format may be a texture map obtained by removing correlation between color components from the texture map in the first color space format.

In the related art, when the texture map of the three-dimensional mesh is encoded, the texture map of the BGR444 format is directly encoded. The decoding efficiency of the video in the BGR444 format is lower due to the fact that the decoding efficiency of the decoding end for decoding videos in different color space formats is different, and the encoding and decoding efficiency of the three-dimensional grid is lower. In this embodiment, in the three-dimensional mesh encoding process, the texture map of the three-dimensional mesh is converted into the texture map of the color space format with higher encoding and decoding efficiency by performing color space format conversion on the texture map of the three-dimensional mesh, so that the encoding and decoding efficiency of the three-dimensional mesh can be improved.

Optionally, the second color space format and the first color space format are different color space formats of the same color space, or the second color space format and the first color space format are different color space formats of the same color space.

Optionally, the first color space format is an RGB color space format and the second color space format is a YUV color space format.

In this embodiment, the first color space format is an RGB color space format, and the second color space format is a YUV color space format, so that when the texture map of the three-dimensional grid is encoded, the texture map of the RGB color space is converted into the texture map of the YUV color space for encoding, and since the efficiency of decoding the video in the YUV color space by the decoding end is higher than the efficiency of decoding the video in the RGB color space by the decoding end, the encoding and decoding efficiency of the three-dimensional grid can be improved through the color space format conversion.

The embodiment of the application also provides a three-dimensional grid coding method, which comprises the following steps:

Optionally, the code stream corresponding to the three-dimensional grid includes the second texture map code stream and a coding result of first indication information, where the first indication information indicates that the coding end does not perform color space format conversion on the texture map of the three-dimensional grid.

Referring to fig. 4, fig. 4 is a flowchart of a three-dimensional grid decoding method according to an embodiment of the present application, which may be applied to a decoding end device, as shown in fig. 4, and the three-dimensional grid decoding method includes the following steps:

step 201, decoding a first texture map code stream in the code stream corresponding to the three-dimensional grid to obtain a texture map in a second color space format;

step 202, performing color space format conversion on the texture map in the second color space format to obtain a texture map in the first color space format;

And 203, performing grid reconstruction processing based on the texture map in the first color space format to obtain a reconstructed three-dimensional grid.

Optionally, the method further comprises:

decoding the coding result of the first indication information in the code stream corresponding to the three-dimensional grid to obtain the first indication information;

the decoding processing is performed on the first texture map code stream in the code stream corresponding to the three-dimensional grid to obtain a texture map in the second color space format, including:

and under the condition that the color space format conversion is carried out on the texture map based on the first indication information, decoding the first texture map code stream in the code stream corresponding to the three-dimensional grid to obtain the texture map in the second color space format.

Optionally, performing color space format conversion on the texture map in the second color space format to obtain a texture map in the first color space format, including:

And under the condition that the texture map is converted from a second color space format to a first color space format based on the first indication information, converting the texture map in the second color space format from the second color space format to the first color space format, and obtaining the texture map in the first color space format.

Optionally, the method further comprises:

and under the condition that the texture map is determined not to be subjected to color space format conversion based on the first indication information, decoding a second texture map code stream in the code streams corresponding to the three-dimensional grid to obtain the texture map in the first color space format.

It should be noted that, as an implementation manner of the decoding side corresponding to the embodiment shown in fig. 3, a specific implementation manner of the embodiment may refer to a related description of the embodiment shown in fig. 3, so that in order to avoid repeated description, the embodiment is not described again, and the same beneficial effects may be achieved.

The embodiment of the application also provides a three-dimensional grid decoding method, which comprises the following steps:

under the condition that the first indication information indicates that the texture map is not subjected to color space format conversion, decoding a second texture map code stream in the code stream corresponding to the three-dimensional grid to obtain a texture map in a first color space format;

The embodiment of the application also provides a Edgebreaker-based lossless encoding and decoding framework and a Edgebreaker-based lossless encoding and decoding method for the three-dimensional grid texture map. As shown in fig. 5, the encoding framework mainly includes a preprocessing module (including a split non-manifold structure module), a connection relation encoding module, a geometric information encoding module, an attribute information encoding module, a texture map lossless color space format conversion and texture map encoding module, and the like. The three-dimensional mesh can be losslessly encoded using Edgebreaker when encoding the three-dimensional mesh.

Taking the first color space format as an RGB color space format, the second color space format as a YUV color space format, and the attribute information as UV coordinates (also described as texture coordinates, also simply referred to as UV or texture) as an example, the process of performing three-dimensional grid coding by the coding end is as follows:

(1) And judging whether the geometric coordinates and the UV coordinates have the same connection relation at the encoding end and recording the information. The information indicating whether the geometric coordinates and the UV coordinates in the mesh have the same connection relationship may be indicated by, for example, setting an identification of whether the geometric coordinates and the UV coordinates in one mesh have the same connection relationship, and the indication method thereof is not limited herein.

(2) Non-manifold points and non-manifold edges that may be present in the grid are split, converting the grid into a manifold grid. Splitting the non-manifold structure is achieved by adding repetition points with identical geometric and attribute information. When the non-manifold is split, if the geometric coordinates and the UV coordinates have the same connection relation, namely, the geometric coordinates and the UV coordinates are in one-to-one correspondence relation, only one group of repeated point index information generated by the non-manifold splitting structure is required to be recorded, and if the geometric coordinates and the UV coordinates have different connection relations, such as that one geometric coordinate vertex corresponds to a plurality of texture coordinate vertexes, the geometric repeated point index information and the UV repeated point index information generated by the non-manifold splitting structure are required to be respectively recorded. The representation of the index information of the repeated points generated by the non-manifold structure can be the index of the target vertex which needs to be combined when the non-manifold structure is restored, or the index of the repeated point group, wherein the points with the same index belong to the same repeated point group, namely the points with the same vertex information, and the representation is not limited.

(3) Information indicating whether the geometric coordinates and the UV coordinates have the same connection relation is encoded. And coding the connection relation by using a Edgebreaker method to obtain a CLERS mode character string capable of simply representing the connection relation, and compressing the mode character string by using entropy coding to obtain a subcode stream of the connection relation. The geometric information of the grid is encoded by using a method such as parallelogram prediction and the like to obtain a geometric information subcode stream. If the grid has the attribute information such as UV coordinates, the UV coordinates of the grid are encoded by using a similar triangle prediction method and the like, so that an attribute information subcode stream is obtained.

(4) An indication (i.e., first indication) is encoded to indicate whether or not to perform lossless color space format conversion on the texture map. If lossless color space format conversion is performed on the texture map, converting the texture map from RGB color space format (i.e. first color space format) to YUV color space format (i.e. second color space format), and encoding the texture map in YUV format by using a video encoder to obtain a texture map subcode stream. The conversion from RGB color space format to YUV color space is emphasized here only, and the specific format of the texture map is not limited, for example, the texture map may be in BGR444 format or in RGB444 format in RGB color space. If the texture map is not color space format converted, the video encoder is directly used to losslessly encode RGB color space video.

(5) The encoding of the non-manifold structure information comprises three parts of information to be encoded, namely information indicating whether the non-manifold structure exists in the grid, identification information of repeated points generated by whether vertexes are non-manifold splitting, and repeated point index information generated by the non-manifold splitting. Wherein, the information indicating whether the non-manifold structure exists in the grid can be represented by setting an identification of whether the non-manifold structure exists in one grid, or the number of the repeated points generated by disassembling the non-manifold structure in the grid can be used for representing, and the representation method is not limited. In encoding non-manifold structure information, information indicating whether a non-manifold structure exists in a mesh is first encoded. If the grid has a non-manifold structure, the grid is divided into two cases, wherein if the geometric coordinates and the UV coordinates have the same connection relation, each vertex is provided with a repeated point which indicates whether the vertex is generated by disassembling the non-manifold and codes the information and repeated point index information generated by disassembling the non-manifold, and if the geometric coordinates and the UV coordinates have different connection relation, each geometric vertex and each UV vertex are respectively provided with a geometric repeated point or a UV repeated point which indicates whether the vertex is generated by disassembling the non-manifold and codes non-manifold identification information of the geometric vertex and index information of the geometric repeated point generated by disassembling the non-manifold and index information of the UV vertex and UV repeated point generated by disassembling the non-manifold.

Taking the first color space format as the RGB color space format, the second color space format as the YUV color space format, and the attribute information as UV coordinates (also may be described as texture coordinates, also may be simply referred to as UV or texture), as shown in fig. 6, the process of performing three-dimensional grid decoding by the decoding end is as follows:

(1) At the decoding end, decoding is carried out to obtain information which indicates whether the geometric coordinates and the UV coordinates in the grid have the same connection relation. Entropy decoding is carried out to obtain CLERS mode character strings, and the mode character strings are used for reconstructing the connection relation between the geometric coordinates and the UV coordinates. The geometrical information of the grid is decoded by using methods such as parallelogram inverse prediction and the like, and the UV coordinates of the grid are decoded by using methods such as similar triangle inverse prediction and the like. In decoding the non-manifold structure information, first, an indication of whether a non-manifold structure exists in the trellis is decoded. If the non-manifold structure exists in the grid, further decoding to obtain non-manifold identification information of the vertex and repeated point index information generated by non-manifold disassembly, merging repeated points generated by non-manifold disassembly, adjusting the connection relation, and recovering the non-manifold structure in the grid.

(2) Decoding the indication information (such as the first indication information) of whether lossless color space format conversion is performed or not, decoding the texture map by using a video decoder, if lossless color space format conversion is performed on the color space format of the texture map at the encoding end, obtaining a texture map in YUV format by decoding, performing lossless color space format conversion on the texture map at the decoding end according to the indication information, and converting the texture map from YUV color space format (namely the second color space format) to RGB color space format (namely the first color space format), thereby realizing lossless encoding and decoding of the texture map. The conversion from YUV color space format to RGB color space format is only emphasized here, and the specific format of the texture map is not limited, for example, the texture map may be in BGR444 format or in RGB444 format in RGB color space. If the color space format of the texture map is not subjected to lossless color space format conversion at the encoding end, the texture map in RGB format is obtained by decoding, and the color space format conversion is not required at the decoding end.

The lossless encoding and decoding of the three-dimensional grid can be completed through the encoding and decoding framework of the embodiment of the application.

As shown in fig. 5, the three-dimensional grid coding frame according to the embodiment of the present application is illustrated by taking the first color space format as the RGB color space format, the second color space format as the YUV color space format, and the attribute information as UV coordinates (which may also be described as texture coordinates, also may be simply referred to as UV or texture) as an example.

(1) In the preprocessing step, firstly, whether the geometric coordinates and the UV coordinates have the same connection relation is judged, then the input grid with the non-manifold structure is split to obtain the manifold grid, and the repeated point information generated by splitting the non-manifold is recorded. It should be noted that this step may also include filtering out the repetition points, adding other preprocessing modules required for encoding, such as virtual points. For ease of illustration, only the modules of the split non-manifold architecture for which embodiments of the present application are directed are listed in fig. 5.

(2) The method comprises the steps of encoding information representing whether geometric coordinates and UV coordinates in a grid have the same connection relation, encoding connection information by using a Edgebreaker method to obtain a pattern character string, entropy encoding the pattern character string, encoding geometric information of the manifold grid, wherein the encoding method of the geometric information is not limited, encoding by using a parallelogram prediction encoding method, if attribute information such as UV coordinates exists in the grid, encoding by using a similar triangle prediction encoding method, and the like, encoding by using a non-manifold representation information is firstly encoded when non-manifold structure information is encoded. If the grid has a non-manifold structure, the grid is divided into two cases according to whether the geometric coordinates and the UV coordinates in the grid have the same connection relationship, namely, the geometric coordinates and the UV coordinates are in one-to-one correspondence, if the geometric coordinates and the UV coordinates in the grid have the same connection relationship, namely, the non-manifold identification information of a group of vertexes and the repeated point index information generated by disassembling the non-manifold are coded according to the same coding sequence, and if the geometric coordinates and the UV coordinates in the grid have different connection relationships, namely, the geometric coordinates and the UV coordinates are not in one-to-one correspondence, the geometric repeated point index information generated by respectively coding the non-manifold identification information of the geometric vertexes and the geometric repeated point index information generated by disassembling the non-manifold, the non-manifold identification information of the UV vertexes and the UV repeated point index information generated by disassembling the non-manifold are coded according to the coding sequence of the geometric coordinates and the UV coordinates. The non-manifold identification information about a vertex here is a repetition point generated by encoding a flag bit for each vertex in the split manifold mesh to identify whether the vertex is a split non-manifold.

(3) An indication may be encoded to indicate whether or not to perform lossless color space format conversion on the texture map. If the texture map is subjected to lossless color space format conversion, the texture map is converted from an RGB color space format (namely a first color space format) to a YUV color space format (namely a second color space format) in a lossless color space format conversion module, and the texture map in the YUV format is encoded by using a video encoder, so that a texture map sub-code stream is obtained. If the texture map is not color space format converted, the video encoder is directly used to losslessly encode RGB color space format video. And finally, mixing the multiple paths of code streams to obtain a final output code stream.

It should be noted that, the sequence of encoding the three-dimensional grid connection relationship and the vertex information may be that the geometric information, the attribute information and the non-manifold structure information are encoded while the connection relationship is encoded, or that the geometric information, the attribute information and the non-manifold structure information are sequentially encoded according to the encoding sequence of the connection relationship after the connection relationship is encoded. In encoding the geometric information and the attribute information of the vertex, the geometric information and the attribute information of the repetition point generated by the non-manifold may be skipped to be encoded, i.e. encoded only once, or may not be skipped to be encoded, and here, whether to skip the encoding of the geometric information and the attribute information of the repetition point generated by the non-manifold is de-emphasized.

As shown in fig. 6, the three-dimensional grid decoding framework of the embodiment of the present application is illustrated by taking the first color space format as the RGB color space format, the second color space format as the YUV color space format, and the attribute information as UV coordinates (which may also be described as texture coordinates, also may be simply referred to as UV or texture) as an example.

(1) First, the code stream is decomposed to obtain each sub-code stream. The method comprises the steps of decoding information representing whether geometric coordinates and UV coordinates in a grid have the same connection relation, entropy decoding connection relation subcode streams to obtain a pattern character string, if the geometric coordinates and the UV coordinates have the same connection relation, only one set of connection relation is needed to be rebuilt, if the geometric coordinates and the UV coordinates have different connection relations, the connection relation of the geometric coordinates and the connection relation of the UV coordinates are needed to be rebuilt respectively, decoding geometric information of the grid by using a decoding method corresponding to an encoding end, decoding attribute information of the grid by using a decoding method corresponding to the encoding end, decoding information of whether a non-manifold exists in the grid when decoding non-manifold structure information, and if the non-manifold structure exists in the grid, decoding information of whether the non-manifold exists according to whether the geometric coordinates and the UV coordinates in the grid have the same connection relation, namely, when the geometric coordinates and the UV coordinates in the grid have the same connection relation, namely, the geometric coordinates and the UV coordinates are in one-to-one correspondence relation, further decoding information of a set of non-manifold identification information of vertexes and repeated point index information generated by one, and non-manifold index information generated by decoding point index information by decoding point information by one when the geometric coordinates and the geometric coordinates in the grid have different connection relations, namely, the geometric coordinates and the UV coordinates in the geometric coordinates are not in one-to be in one-to correspond to the connection relation. In the post-processing step, the repeated points generated by disassembling the non-manifold are combined, and the connection relation is adjusted to recover the non-manifold structure in the grid. And (5) completing lossless encoding and decoding containing the non-manifold structural grids. It should be noted that the post-processing step may also include post-processing modules required for recovering the filtered repeated points, deleting the added virtual vertices, and so on for correct decoding. For ease of illustration, only the modules for restoring non-manifold structures for which embodiments of the present application are directed are listed in FIG. 6.

(2) Decoding the indication information (such as the first indication information) of whether lossless color space format conversion is performed or not, decoding the texture map by using a video decoder, if lossless color space format conversion is performed on the color space format of the texture map at the encoding end, obtaining a texture map in YUV format by decoding, performing lossless color space format conversion on the texture map at the decoding end according to the indication information, and converting the texture map from YUV color space format (namely the second color space format) to RGB color space format (namely the first color space format), thereby realizing lossless encoding and decoding of the texture map. If the color space format of the texture map is not subjected to lossless color space format conversion at the encoding end, the texture map in RGB format is obtained by decoding, and the color space format conversion is not required at the decoding end.

The following describes a three-dimensional mesh codec method by a specific embodiment:

encoding end:

As shown in fig. 5, the three-dimensional mesh lossless coding framework is mainly divided into five parts, namely split non-manifold structure, connection relation coding, geometric information coding, attribute information coding and non-manifold structure information coding in preprocessing. In this embodiment, the description will be made on each part by taking the example that the first color space format is an RGB color space format, the second color space format is a YUV color space format, and the attribute information is UV coordinates (which may also be described as texture coordinates, also may be simply referred to as UV or texture):

(1) Pretreatment of

Inputting an original grid;

And outputting information representing whether the geometric coordinates and the UV coordinates in the grid have the same connection relation, manifold grid and repeated point information generated by non-manifold disassembly.

Before the non-manifold structure is removed, it is first determined whether the geometric coordinates and the UV coordinates have the same connection relationship. The method comprises the steps of judging whether the number of the geometric vertexes is consistent with the number of the UV vertexes or not, judging whether the geometric connection relation and the UV connection relation between the geometric triangles and the UV triangles are consistent if the geometric vertexes are consistent with the number of the UV vertexes, wherein the geometric coordinates and the UV coordinates have different connection relations if the geometric triangles are inconsistent with the UV triangles, and the geometric coordinates and the UV coordinates have different connection relations if the number of the geometric vertexes is inconsistent with the number of the UV vertexes, but the number of the geometric triangles is consistent with the number of the UV triangles. Other methods of determination are also possible, and the determination method is not limited herein.

The split non-manifold structure is mainly divided into two parts, namely a split non-manifold edge and a split non-manifold point.

The first step in splitting the non-manifold sides is to find the non-manifold sides. The non-manifold edge is judged if one edge exists in three or more triangles at the same time. The method specifically comprises the steps of establishing a data structure to store triangles where each edge is located, searching the number of triangles corresponding to the edges to find out non-manifold edges, or establishing a corresponding relation between corners and edges in a grid by constructing a corner table (CornerTable), and further finding out the non-manifold edges. Specifically, for a manifold grid, each edge is at most opposite two corners, the opposite two corners being referred to as diagonal. As shown in fig. 7, angle a is opposite angle d from side bc, angle a is diagonal to angle d, and for non-manifold sides there are three or more diagonals. Therefore, the non-manifold sides can be found out through the corresponding relation between the corners and the sides.

The second step in splitting the non-manifold edges is to add vertices and modify the connection relationships. After the non-manifold edge is found, repeated vertexes are respectively created for the two vertexes of the non-manifold edge, one triangle t where the non-manifold edge is located is selected, a new triangle t 'is formed by a third vertex in the triangle and the newly added two vertexes, the original triangle t is replaced by t', and the process is iterated until the non-manifold edge is converted into the manifold edge.

Splitting non-manifold points first requires construction CornerTable, establishing a correspondence between each vertex and the corner of that vertex. A two-step operation is performed for each vertex. In the first step, all angles adjacent to a certain angle of the vertex and forming a sector are sequentially traversed, and the vertex and the traversed angle are marked as traversed. If there are vertices for which there are no traversing angles after the process is performed, the vertex is indicated as a non-manifold point. And secondly, for each non-manifold point, creating a repeated point, modifying the connection relation, connecting the angles which are not traversed in the first step to the newly added repeated points, and splitting the non-manifold point into two manifold vertexes. This process is repeated until all vertices are converted to manifold points.

If the geometric coordinates and the UV coordinates have the same connection relation, executing the process once, recording a group of repeated point information generated by the process, and if the geometric coordinates and the UV coordinates have different connection relation, executing the process once by the geometric and UV respectively, namely respectively constructing the geometric and UV CornerTable, respectively splitting the geometric non-manifold edge and the geometric non-manifold point, splitting the UV non-manifold edge and the UV non-manifold point, and respectively recording the geometric repeated point information and the UV repeated point information generated by the process.

(2) Connection relation coding

Inputting connection relation of manifold grids, which represents information whether the geometric coordinates and UV coordinates in the grids have the same connection relation;

and outputting the encoded connection relation subcode stream and the vertex coding sequence.

The present embodiment encodes the connection of the three-dimensional mesh using Edgebreaker method, represents the connection of the mesh by creating CornerTable, and traverses all triangles in the mesh with CornerTable, generating the CLERS pattern string of Edgebreaker.

CornerTable are used to represent the relationship between corners and vertices in the mesh and triangles. The triangles need to be numbered first diagonally before CornerTable is built, traversing the triangles in the order of the triangle patches in the mesh, and for each triangle, the angles are numbered in a counter-clockwise order, if the mesh has f triangle patches, then the mesh will have 3f angles. The advantage of this numbering is that the triangle number where the current angle is located can be calculated by the number of angles, as shown in formula (1), and the numbers of the previous angle c _p and the next angle c _n of the current angle c in the anticlockwise direction, as shown in formulas (2) and (3).

f_i=c/3 (1)

Where c is the index of the current angle, f _i is the sequence number of the triangle in which the current angle c is located, "/" is the integer division, and the result is rounded down.

c_p＝(f_i*3)+(c-1)%3 (2)

Wherein c is the index of the current angle, f _i is the sequence number of the triangle where the current angle c is located, "x" is multiplication, and "%" is modulo operation.

c_p＝(f_i*3)+(c+1)%3 (3)

CornerTable includes four parts, namely a V table, an O table, a U table and an M table. Wherein, the V table stores the vertex index corresponding to each angle, the O table stores the diagonal index of each angle, the U table stores the mark whether each triangle is traversed in the traversing process, and the M table stores the mark whether each vertex is traversed in the traversing process.

Using CornerTable, a relationship as shown in fig. 8 can be constructed, where c represents the current angle, c.p represents the previous angle (in a counterclockwise direction) of the current angle c, and c.n represents the next angle of the current angle c. c.o is the diagonal of the current angle c, which can be obtained by looking up an O table. And c.t is the sequence number of the triangle where c is located, and can be calculated by the formula 1. c.v denotes the vertex of the current angle, which can be found by looking up the V table. c.l denotes the left corner of the current corner c, which is obtained by looking up the diagonal of c.p in the O table, and c.r denotes the right corner of the current corner c, which is obtained by looking up the diagonal of c.n in the O table.

After the relationships between the angles and the vertices and triangles are constructed using CornerTable, the mesh can be traversed in a spiral order to obtain a CLERS pattern string of Edgebreaker representing the mesh connection relationships. At this time, the judgment conditions and the traversal rules of the five modes are shown in fig. 9. The current traversing angle is x, if the vertex x.v corresponding to x is not accessed, the current triangle is in a C mode, and the triangle to be traversed next is the triangle in which x.r is located, otherwise, if x.l is accessed, the current triangle is in an L mode, and the triangle to be traversed next is the triangle in which x.r is located, if x.r is accessed, the current triangle is in an R mode, and the triangle to be traversed next is the triangle in which x.l is located, if x.v is accessed, and neither of x.l nor x.r is accessed, the current triangle is in an S mode, two branches are generated by the traversing path, the triangle to be traversed first is in the triangle in which x.r is located by adopting the principle of depth-first traversing, and x.l is stored in the triangle stack after the completion of the traversing of x.r is waited, if both the triangle to be traversed current and the triangle to be traversed is in an E mode, and the current traversing path is traversed to the end point of the triangle if both the triangle to be traversed is accessed.

An initial triangle is randomly selected in the grid, the triangle in the grid is traversed according to the rule, and CLERS-mode character strings are generated. When the traversal path is terminated, but the grid still exists as a traversed triangle, a non-traversed triangle is randomly selected and the next traversal is started until all the triangles in the grid are traversed.

And compressing CLERS mode character strings by using entropy coding to obtain a final connection information code stream.

If the geometric coordinates and the UV coordinates have the same connection relationship, the process is executed once, and if the geometric coordinates and the UV coordinates have different connection relationships, the geometric triangles and the texture triangles are consistent and corresponding in number, and only the corresponding geometric coordinate indexes and UV coordinate indexes are not in one-to-one correspondence relationship, so that CLERS mode character strings are constructed once according to the geometric CornerTable and are coded. In this case, for UV, after the pattern string encoding of each connected region of the geometry is completed, the angle that has been traversed is traversed, and the difference information of the UV connection relationship and the geometry connection relationship is recorded and encoded according to the TC table and OTC table of UV. Wherein the TC table stores UV vertex indexes corresponding to each corner in the texture triangle, and the OTC table stores each diagonal index in the texture triangle.

(3) Geometric information encoding

Inputting geometric information and connection relation coding sequence of manifold grids;

and outputting the geometric information subcode stream and the geometric information coding sequence.

The encoded geometric information may be encoded using a variety of methods, such as a difference predictive encoding algorithm, a parallelogram predictive encoding algorithm, a multi-parallelogram predictive encoding algorithm, etc., where specific encoding methods are de-emphasized. Taking parallelogram predictive coding algorithm as an example, a, b, c, d vertexes are arranged to form two adjacent triangles in the grid as shown in fig. 10.

Wherein the geometric information of the points a, b and c is encoded, the geometric information of the point d is to be encoded, and the predicted value d' of the geometric coordinates of the point d can be calculated by using the formula (4).

d′(x,y,z)=b(x,y,z)+c(x,y,z)-a(x,y,z)(4)

After d 'is obtained, calculating the difference between d' and d-point three-dimensional coordinates, as shown in formula (5):

Δd(x,y,z)=d(x,y,z)-d′(x,y,z)(5)

And performing entropy coding on the delta d to obtain a code stream of the geometric information.

For triangles that cannot be predicted using parallelograms, such as triangles at the mesh boundaries, the difference coding method is used to encode the geometric information. I.e. using the coordinate values of neighboring coded vertices as predictors of the current vertex coordinates, a residual is calculated and predicted.

(4) Attribute information encoding

Inputting attribute information and connection relation coding sequence of manifold grids;

and outputting the attribute information subcode stream and the coding sequence of the attribute information.

The three-dimensional mesh attribute information generally includes UV coordinates, normal vectors, and the like, taking UV coordinates as an example. There are a number of coding methods that may be employed for UV coordinates, including differential predictive coding, parallelogram predictive coding, and similar triangle predictive coding, and the like, and specific coding methods are not emphasized here. The similar triangle prediction algorithm is described below.

Firstly, selecting a triangle in a three-dimensional grid as an initial triangle, directly encoding UV coordinates without predicting three vertexes of the initial triangle, and storing edges of the initial triangle into an edge set, wherein the set can be a data structure meeting a certain access criterion. The edges τ in one set are then fetched, predicting the pair-vertex UV coordinates of τ in the next new triangle. And placing two sides of the new triangle other than τ into the collection. The point to be predicted is marked as point C, two end points of the side tau are respectively N and P, the vertex of the triangle pair adjacent to the new triangle through tau is marked as O, and the projection point X of C on tau is marked. As shown in fig. 11, since the UV coordinates of the three points N, P, and O are encoded before the C point, the UV coordinates of the C point can be predicted using the three points. The specific calculation flow is as follows:

Let C _uv,X_uv,N_uv,P_uv,O_uv be the UV coordinates of each point and C _G,X_G,N_G,P_G,O_G be the geometric coordinates of each point.

First, the UV coordinates of the point X are calculated using equation (6) and equation (7):

Wherein, The vector representations with G as the subscript are vector representations of geometric coordinates among corresponding points, and similarly,The vector representations with UV as subscripts are vector representations of UV coordinates between the corresponding points.

Calculating vectors using (8)Rotated () represents a 90 degree flip of the vector:

finally, calculating the C point predicted UV coordinate Pred _C by using the formula (9), the formula (10) and the formula (11):

Wherein, AndThe vectors of UV coordinates between the C point and the O point are represented, but are represented by different calculation modes/values.

And after obtaining the predicted value of the UV coordinates, subtracting the predicted value from the original UV coordinates to obtain a residual value.

The encoding UV coordinates steps are as follows:

(a) And selecting an initial triangle from the connectivity relation, and directly encoding UV coordinates of three vertexes of the initial triangle without prediction. The initial triangle edge is stored in an edge set.

(B) And selecting the side tau from the set according to the access criterion, and encoding the UV coordinates of the new triangle formed by tau on the vertex. And calculating the predicted value of the point to be coded according to the UV coordinate predicted value calculation process by utilizing the three-dimensional to two-dimensional projection relation of the triangle. Subtracting the predicted value from the original value of the UV coordinates to obtain a residual error.

(C) Adding two sides of the new triangle into the side set, and removing the side tau at the top of the set. And (3) taking out the next edge from the set, continuing to encode the UV coordinates of the pair of vertexes of the adjacent triangle of the edge, and returning to the step (3) until the UV coordinates of all vertexes are encoded.

(D) Entropy coding UV coordinate residual errors and outputting UV coordinate code streams.

(5) Non-manifold structure information coding

The input is that the information representing whether the geometric coordinates and UV coordinates in the grid have the same connection relation, the information representing whether the non-manifold structure exists in the grid, the non-manifold mark of the vertex, the repeated point index information generated by disassembling the non-manifold, the geometric information coding sequence and the attribute information coding sequence;

and outputting the non-manifold structure information subcode stream.

First, information indicating whether a non-manifold structure exists in a mesh is encoded. Taking an example of setting whether the mark of the non-manifold structure exists or not, if the non-manifold structure does not exist in the grid, namely, the number of the repeated points generated by disassembling the non-manifold is 0, the mark is set to 0, the non-manifold mark of the vertex and the repeated point index information generated by disassembling the non-manifold do not need to be encoded any more, and if the non-manifold structure exists in the grid, namely, the number of the repeated points generated by disassembling the non-manifold is greater than 0, the mark is set to 1, and then the non-manifold mark of the vertex and the repeated point index information generated by disassembling the non-manifold are encoded.

The repeat points resulting from the non-manifold disassembly include both geometric repeat points and UV repeat points. According to whether the geometric coordinates and the UV coordinates in the grid have the same connection relation, the repeated point index information generated by coding the non-manifold marks and the non-manifold splitting of the vertexes is divided into two cases, wherein the first case is that the geometric coordinates and the UV coordinates in the grid have the same connection relation, namely, the geometric coordinates and the UV coordinates are in one-to-one correspondence relation, the repeated point index information generated by directly coding the non-manifold marks and the non-manifold splitting of a group of vertexes can be obtained according to the coding sequence of the geometric coordinates and the UV coordinates of the coding end, and the second case is that the geometric coordinates and the UV coordinates in the grid have different connection relations, namely, the geometric coordinates and the UV coordinates are not in one-to-one correspondence relation, the geometric repeated point index information generated by respectively coding the non-manifold marks and the non-manifold splitting of the geometric vertexes, the UV repeated point index information generated by respectively coding the non-manifold marks and the UV vertexes of the vertexes can be obtained according to the geometric coordinate coding sequence and the UV coordinate coding sequence of the coding end.

The method is characterized in that if the geometric coordinates and the UV coordinates in the grid have the same connection relation, a flag bit is set for each vertex in the manifold grid and used for indicating whether the point at the current position is a repeated point generated by disassembling a non-manifold or not and encoding repeated point index information generated by disassembling the non-manifold, and if the geometric coordinates and the UV coordinates in the grid have different connection relation, a flag bit is set for each geometric vertex and each UV vertex in the manifold grid and used for indicating whether the geometric vertex and the UV vertex at the current position are repeated points generated by disassembling the non-manifold or not and encoding the geometric repeated point index information and the UV repeated point index information generated by disassembling the non-manifold respectively. And then entropy coding is carried out on the flag bit binary character string sequences arranged according to the corresponding coding sequence and the repeated point index information generated by non-manifold splitting, so as to obtain the non-manifold structure information code stream.

The non-manifold structure information code stream can be stored in various modes in the total code stream, namely, the non-manifold structure information code stream is used as a single sub-code stream, the geometric non-manifold structure information code stream is stored in the geometric information sub-code stream, the UV non-manifold structure information code stream is stored in the attribute information sub-code stream, and the geometric non-manifold structure information code stream and the UV non-manifold structure information code stream can be stored in the total code stream as two sub-code streams. The way in which the non-manifold structure information streams are stored in the overall stream is de-emphasized here.

(6) Lossless color space format conversion module

Input a texture map in BGR444 format (illustrated here in BGR444 format);

And outputting a texture map in YUV444 format.

An indication may be encoded to indicate whether or not to perform lossless color space format conversion on the texture map. If the texture map is subjected to lossless color space format conversion, the texture map in the input RGB color space format (namely, the first color space format) is subjected to lossless color space format conversion, and the texture map in the YUV color space format (namely, the second color space format) is obtained. There are a number of implementations of lossless color space format conversion, and embodiments of the present application are not limited to a particular implementation of lossless color space format conversion. For example, the texture map may be converted from an RGB color space format to a YUV color space format using a color space format conversion method as shown in equations (12) - (14).

V=R-G (13)

Alternatively, the texture map may be converted from an RGB color space format to a YUV color space format using a color space format conversion method as shown in equations (15) - (17).

U=R-G (16)

V=B-G (17)

Where round () represents a round down function.

(7) Texture map coding module

If the texture map is losslessly color space format converted, a video encoder is used to losslessly encode video in YUV color space format. If the texture map is not color space format converted, a video encoder is used to losslessly encode video in RGB color space format. The video encoder used is not limited herein.

Decoding end:

As shown in fig. 6, the three-dimensional mesh lossless decoding framework of the embodiment of the application is mainly divided into six parts, namely connection relation decoding, geometric information decoding, attribute information decoding, non-manifold structure information decoding, reconstruction of manifold meshes and recovery of non-manifold structures in post-processing. In this embodiment, the description will be made on each part by taking the example that the first color space format is an RGB color space format, the second color space format is a YUV color space format, and the attribute information is UV coordinates (which may also be described as texture coordinates, also may be simply referred to as UV or texture):

(1) Connection relation decoding

Inputting a connection relation subcode stream to be decoded, wherein the connection relation subcode stream to be decoded represents information whether the geometric coordinates and the UV coordinates have the same connection relation;

and outputting the connection relation of the manifold grids and the decoded vertex sequence.

And decoding the connection relation subcode stream to obtain a mode character string. The pattern strings are traversed in a certain order (positive or negative) and the connection relationships are reconstructed from the corresponding patterns in the strings. And if the geometric coordinates and the UV coordinates have different connection relations, reconstructing the geometric connection relation according to the decoded character string, traversing the angle in the communication area which is decoded currently and the difference information of the UV connection relation and the geometric connection relation in the communication area which is decoded currently, and reconstructing the connection relation of the UV coordinates. In addition, the traversal order of the vertices is output to the geometry information and attribute information decoding module.

(2) Geometric information decoding

Inputting a decoding sequence of the geometric information subcode stream and the connection relation;

Outputting the geometric information of the manifold grid.

The decoding process of the grid geometric coordinates is the inverse of the encoding process, namely, the coordinate prediction residual is firstly entropy decoded. And predicting the predicted coordinates of the point to be decoded according to the parallelogram rule according to the decoded triangle. And adding the residual error value obtained by entropy decoding to the predicted coordinate to obtain the position of the geometric coordinate to be decoded. The vertex traversal order here is the same as the vertex order of the encoded geometry information. It should be noted that, instead of using predictive coding, the geometric coordinates of the initial triangles are directly coded. And after the decoding end decodes the geometric coordinates of the triangle, the geometric coordinates of vertexes of other triangles are traversed and decoded as the initial triangle. In addition, other decoding methods may be used herein, and specific decoding methods are not emphasized as long as they correspond to the encoding end.

(3) Attribute information decoding

Inputting an attribute information code stream to be decoded and a decoding sequence of a connection relation;

and outputting the attribute information of the manifold mesh reconstruction.

Taking UV coordinates as an example, a decoding method corresponding to the encoding end is used for decoding UV coordinates, and a specific decoding method is not emphasized here. The decoding process using the similar triangle prediction algorithm is described below.

The decoding UV coordinates steps are as follows:

a. Entropy decoding the UV coordinate code stream.

B. The UV coordinates of the three vertices of the initial triangle, which is directly encoded instead of the residual, are decoded, where no prediction value is calculated. The initial triangle edge is stored in an edge set.

C. And selecting an edge tau from the set according to an access criterion, and decoding UV coordinates of a new triangle formed by tau on the vertex. Firstly, calculating the UV coordinate predicted value of the point to be decoded by using a three-dimensional to two-dimensional mapping relation of the triangle and a calculation mode consistent with the coding end. And adding the predicted value and the residual error decoded by the entropy to obtain the reconstructed UV coordinate.

D. Adding two sides of the new triangle into the side set, and removing the side tau at the top of the set. And (c) taking out the next edge from the set, continuing to decode the UV coordinates of the pair of vertexes of the adjacent triangle of the edge, and returning to the step (c) until the decoding of the UV coordinates of all vertexes is completed.

(4) Non-manifold structure information decoding

Inputting a non-manifold structure information subcode stream, information representing whether the geometric coordinates and UV coordinates in the grid have the same connection relation, a geometric information decoding sequence and an attribute information decoding sequence;

And outputting information indicating whether the non-manifold structure exists in the grid, non-manifold identification of the vertexes and repeated point index information generated by non-manifold disassembly.

First, the decoding results in information in the grid indicating whether a non-manifold structure is present. Taking the information as an example of whether the mark of the non-manifold exists or not, if the mark is 0, the non-manifold mark of the vertex and the repeated point index information generated by the non-manifold disassembly are not needed to be decoded, a module for recovering the non-manifold structure is skipped, and if the mark is 1, the non-manifold mark of the vertex and the repeated point index information generated by the non-manifold disassembly are decoded.

The decoding of the repeated point index information generated by the non-manifold identification and the non-manifold disassembly of the vertexes adopts a method corresponding to the coding end, and is divided into two cases according to whether the geometric coordinates and the UV coordinates have the same connection relation, wherein if the geometric coordinates and the UV coordinates have the same connection relation, entropy decoding is carried out to obtain a group of repeated point index information generated by the non-manifold identification and the non-manifold disassembly of the vertexes, and if the geometric coordinates and the UV coordinates have different connection relations, the decoding is carried out to obtain the geometric repeated point index information generated by the non-manifold identification and the non-manifold disassembly of the geometric vertexes, the non-manifold identification of the UV vertexes and the UV repeated point index information generated by the non-manifold disassembly. This information is recorded and output to the resume non-manifold configuration module.

(5) Reconstructing manifold grids

Inputting connection relation of manifold grids, geometric information of manifold grids and attribute information of manifold grids;

Outputting the manifold grid.

The manifold mesh can be directly reconstructed by utilizing the connection relation, the geometric information and the attribute information of the manifold mesh.

(6) Restoring non-manifold structures in post-processing

Inputting manifold grids, non-manifold marks of vertexes, repeated point index information generated by disassembling non-manifold, and information representing whether geometric coordinates and UV coordinates in the grids have the same connection relation;

and (3) outputting, namely reconstructing the non-manifold grid.

The non-manifold edge is the same as the recovery process of the non-manifold point. Taking the repeated point index information generated by non-manifold splitting as an example of the repeated point group index, all the vertexes can be traversed according to the decoding sequence of the vertexes, a hash table is established according to the non-manifold identification of the vertexes, the key of the hash table is the repeated point group index generated by non-manifold splitting, and the value is the index of the target vertex to be combined. If the current vertex is a repeated point generated by removing a non-manifold, the index of the current vertex is not updated, if the current vertex is a repeated point generated by removing a non-manifold and is a target vertex to be combined by combining the repeated point, the current vertex corresponds to the index of the current vertex, namely, the index of the current vertex is not updated, the repeated point group index of the current vertex and the index of the current vertex in a reconstructed manifold grid are added in a hash table, and if the current vertex is a repeated point generated by removing a non-manifold and is not a target vertex to be combined by combining the repeated point group index of the current vertex, the index of the target vertex to be combined by the current vertex in the reconstructed manifold grid is searched in the hash table according to the repeated point group index of the current vertex, so that the operation of combining the repeated point generated by removing the non-manifold is performed, namely, the current vertex index is updated to the index of the corresponding target vertex to be combined by the repeated point. And finally, updating the geometric coordinate list and the UV coordinate list, and updating indexes of the geometric vertexes and the UV vertexes in the connection relation to obtain the reconstructed non-manifold grid.

If the geometric coordinates and the UV coordinates have different connection relations, traversing the geometric vertexes and the UV vertexes according to the decoding sequence of the geometric vertexes and the UV vertexes, establishing a geometric hash table and a UV hash table according to the non-manifold identifications of the geometric vertexes and the UV vertexes, respectively storing geometric repeated point index information generated by disassembling the non-manifold, an index of a geometric target vertex to be combined in the reconstructed manifold, UV repeated point index information generated by disassembling the non-manifold and an index of a UV target vertex to be combined in the reconstructed manifold, respectively executing the operations of judging and combining the repeated points generated by disassembling the non-manifold, updating a geometric coordinate list and a UV coordinate list, updating the vertex geometric index and the UV vertex index in the connection relations, and obtaining the non-manifold grid with different connection relations of the reconstructed geometric coordinates and the UV coordinates.

(8) Texture map decoding module

Decoding the indication information (such as the first indication information) of whether lossless color space format conversion is performed, and decoding the texture map by using a video decoder, wherein if lossless color space format conversion is performed on the color space format at the encoding end, the texture map in YUV format is obtained by decoding, and if lossless color space format conversion is not performed on the color space format at the encoding end, the texture map in RGB format is obtained by decoding.

(9) Lossless color space format conversion module

Inputting a texture map in YUV 444 format;

Output a texture map in BGR444 format (BGR 444 format is taken here as an example).

If the color space format is subjected to lossless conversion, the texture map of the input YUV color space format (namely, the second color space format) is subjected to lossless color space format conversion, and the texture map of the RGB color space format (namely, the first color space format) is obtained. There are a number of implementations of lossless color space format conversion, and the present embodiment is not limited to a particular implementation of lossless color space format conversion. For example, the inverse conversion method corresponding to the color space format conversion method shown in the formula (12) -formula (14) is as shown in (18) - (20).

R=V+G (19)

The reverse conversion method corresponding to the color space format conversion method shown in the formulas (15) - (17) is as shown in (21) - (23).

R=U+G (22)

B=V+G (23)

Where round () represents a round down function.

In the related art, for lossless encoding of texture maps of a three-dimensional grid, a video encoder is directly used to encode texture maps in BGR444 format, resulting in low lossless encoding efficiency of texture maps. The embodiment of the application provides a Edgebreaker-based lossless encoding and decoding method for a three-dimensional grid texture map. Taking the first color space format as an RGB color space format and the second color space format as a YUV color space format as an example, decoding at a decoding end to obtain indication information indicating whether lossless color space format conversion is performed or not, if lossless color space format conversion is performed on the color space format of the texture map at an encoding end, decoding the texture map by using a video decoder to obtain a texture map in the YUV format, performing lossless color space format conversion on the texture map, and converting the texture map from the YUV color space format (namely, the second color space format) to the RGB color space format (namely, the first color space format), thereby realizing lossless encoding and decoding of the texture map. It should be noted that, this embodiment converts the texture map from the YUV color space format to the RGB color space format, but the specific format of the texture map is not limited, for example, the texture map may be in the RGB color space format, which is BGR444 format, or in the RGB444 format. If the color space format of the texture map is not subjected to lossless color space format conversion at the encoding end, a video decoder is used for decoding the video in the RGB color space format. The embodiment of the application can improve the encoding and decoding efficiency of the three-dimensional grid.

It should be noted that, in the three-dimensional grid coding method provided by the embodiment of the present application, the execution body may be a three-dimensional grid coding device, or a control module of the three-dimensional grid coding device for executing the three-dimensional grid coding method. In the embodiment of the present application, a method for executing grid coding by using a three-dimensional grid coding device is taken as an example, and the three-dimensional grid coding device provided by the embodiment of the present application is described.

Referring to fig. 12, fig. 12 is a block diagram of a three-dimensional trellis encoding device provided in an embodiment of the application, and as shown in fig. 12, a three-dimensional trellis encoding device 300 includes:

the conversion module 301 is configured to perform color space format conversion on a texture map in a first color space format of the three-dimensional grid, so as to obtain a texture map in a second color space format;

The first encoding module 302 is configured to encode the texture map in the second color space format to obtain a first texture map code stream.

Optionally, the conversion module is specifically configured to:

Optionally, the apparatus further comprises:

And the second coding module is used for coding the texture map in the first color space format under the condition that the texture map in the three-dimensional grid is not converted in color space format, so as to obtain a second texture map code stream.

The three-dimensional grid coding device in the embodiment of the application can be a device, a device with an operating system or an electronic device, and also can be a component, an integrated circuit or a chip in a terminal. The apparatus or electronic device may be a mobile terminal or a non-mobile terminal. By way of example, mobile terminals may include, but are not limited to, the types of terminals listed above, and non-mobile terminals may be servers, network attached storage (Network Attached Storage, NAS), personal computers (personal computer, PCs), televisions (TVs), teller machines, self-service machines, etc., and embodiments of the present application are not limited in particular.

The three-dimensional grid coding device provided by the embodiment of the application can realize each process realized by the method embodiment of fig. 3 and achieve the same technical effect, and in order to avoid repetition, the description is omitted here.

It should be noted that, in the three-dimensional grid decoding method provided by the embodiment of the present application, the execution body may be a three-dimensional grid decoding device, or a control module of the three-dimensional grid decoding device for executing the three-dimensional grid decoding method. In the embodiment of the present application, a method for executing grid decoding by using a three-dimensional grid decoding device is taken as an example, and the three-dimensional grid decoding device provided by the embodiment of the present application is described.

Referring to fig. 13, fig. 13 is a block diagram of a three-dimensional trellis decoding device according to an embodiment of the present application, and as shown in fig. 13, a three-dimensional trellis decoding device 400 includes:

a first decoding module 401, configured to decode a first texture map code stream in the code streams corresponding to the three-dimensional grid, to obtain a texture map in a second color space format;

A conversion module 402, configured to perform color space format conversion on the texture map in the second color space format, so as to obtain a texture map in the first color space format;

And a reconstruction module 403, configured to perform a grid reconstruction process based on the texture map in the first color space format, so as to obtain a reconstructed three-dimensional grid.

Optionally, the apparatus further comprises:

the second decoding module is used for decoding the encoding result of the first indication information in the code stream corresponding to the three-dimensional grid to obtain the first indication information;

the first decoding module is specifically configured to:

Optionally, the first decoding module is specifically configured to:

Optionally, the apparatus further comprises:

and the third decoding module is used for decoding a second texture map code stream in the code stream corresponding to the three-dimensional grid under the condition that the texture map is determined not to be subjected to color space format conversion based on the first indication information, so as to obtain the texture map in the first color space format.

The three-dimensional grid decoding device in the embodiment of the application can be a device, a device with an operating system or an electronic device, and also can be a component, an integrated circuit or a chip in a terminal. The apparatus or electronic device may be a mobile terminal or a non-mobile terminal. By way of example, mobile terminals may include, but are not limited to, the types of terminals listed above, and non-mobile terminals may be servers, network attached storage (Network Attached Storage, NAS), personal computers (personal computer, PCs), televisions (TVs), teller machines, self-service machines, etc., and embodiments of the present application are not limited in particular.

The three-dimensional grid decoding device provided by the embodiment of the application can realize each process realized by the method embodiment of fig. 4 and achieve the same technical effect, and in order to avoid repetition, the description is omitted here.

Optionally, as shown in fig. 14, the embodiment of the present application further provides a communication device 500, including a processor 501 and a memory 502, where the memory 502 stores a program or instructions that can be executed on the processor 501, for example, when the communication device 500 is an encoding end device, the program or instructions implement the steps of the foregoing three-dimensional grid encoding method embodiment when executed by the processor 501, and achieve the same technical effects. When the communication device 500 is a decoding end device, the program or the instruction, when executed by the processor 501, implements the steps of the foregoing three-dimensional grid decoding method embodiment, and the same technical effects can be achieved, so that repetition is avoided, and no further description is given here.

The embodiment of the application also provides electronic equipment which comprises a processor and a communication interface, wherein the processor is used for carrying out color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain a texture map in the second color space format, and carrying out coding processing on the texture map in the second color space format to obtain a first texture map code stream. The embodiment of the electronic equipment corresponds to the embodiment of the three-dimensional grid coding method, and all implementation processes and implementation modes of the embodiment of the three-dimensional grid coding method can be applied to the embodiment of the electronic equipment and can achieve the same technical effects.

The embodiment of the application also provides electronic equipment which comprises a processor and a communication interface, wherein the processor is used for decoding a first texture map code stream in a code stream corresponding to a three-dimensional grid to obtain a texture map in a second color space format, performing color space format conversion on the texture map in the second color space format to obtain a texture map in the first color space format, and performing grid reconstruction processing based on the texture map in the first color space format to obtain a reconstructed three-dimensional grid. The embodiment of the electronic equipment corresponds to the embodiment of the three-dimensional grid decoding method, and all implementation processes and implementation modes of the embodiment of the three-dimensional grid decoding method can be applied to the embodiment of the electronic equipment and can achieve the same technical effects.

Specifically, the electronic device may be a terminal. Fig. 15 is a schematic hardware structure of a terminal for implementing an embodiment of the present application.

The terminal 600 includes, but is not limited to, at least some of the components of a radio frequency unit 601, a network module 602, an audio output unit 603, an input unit 604, a sensor 605, a display unit 606, a user input unit 607, an interface unit 608, a memory 609, and a processor 610, etc.

Those skilled in the art will appreciate that the terminal 600 may further include a power source (e.g., a battery) for powering the various components, and the power source may be logically coupled to the processor 610 by a power management system so as to perform functions such as managing charging, discharging, and power consumption by the power management system. The terminal structure shown in fig. 15 does not constitute a limitation of the terminal, and the terminal may include more or less components than shown, or may combine some components, or may be arranged in different components, which will not be described in detail herein.

It should be appreciated that in embodiments of the present application, the input unit 604 may include a graphics processing unit (Graphics Processing Unit, GPU) 6041 and a microphone 6042, with the GPU 6041 processing image data of still pictures or video obtained by an image capturing device (e.g., a camera) in a video capturing mode or an image capturing mode. The display unit 606 may include a display panel 6061, and the display panel 6061 may be configured in the form of a liquid crystal display, an organic light emitting diode, or the like. The user input unit 607 includes at least one of a touch panel 6071 and other input devices 6072. The touch panel 6071 is also referred to as a touch screen. The touch panel 6071 may include two parts of a touch detection device and a touch controller. Other input devices 6072 may include, but are not limited to, a physical keyboard, function keys (e.g., volume control keys, switch keys, etc.), a trackball, a mouse, a joystick, and so forth, which are not described in detail herein.

In the embodiment of the present application, after receiving the downlink data from the network side device, the radio frequency unit 601 may transmit the downlink data to the processor 610 for processing, and in addition, the radio frequency unit 601 may send the uplink data to the network side device. Typically, the radio frequency unit 601 includes, but is not limited to, an antenna, an amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like.

The memory 609 may be used to store software programs or instructions and various data. The memory 609 may mainly include a first storage area storing programs or instructions and a second storage area storing data, wherein the first storage area may store an operating system, application programs or instructions (such as a sound playing function, an image playing function, etc.) required for at least one function, and the like. Further, the memory 609 may include volatile memory or nonvolatile memory, or the memory 609 may include both volatile and nonvolatile memory. The nonvolatile Memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable EPROM (EEPROM), or a flash Memory. The volatile memory may be random access memory (Random Access Memory, RAM), static random access memory (STATIC RAM, SRAM), dynamic random access memory (DYNAMIC RAM, DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate Synchronous dynamic random access memory (Double DATA RATE SDRAM, DDRSDRAM), enhanced Synchronous dynamic random access memory (ENHANCED SDRAM, ESDRAM), synchronous link dynamic random access memory (SYNCH LINK DRAM, SLDRAM), and Direct random access memory (DRRAM). Memory 609 in embodiments of the present application includes, but is not limited to, these and any other suitable types of memory.

The processor 610 may include one or more processing units, and optionally, the processor 610 integrates an application processor that primarily processes operations involving an operating system, user interface, application programs, etc., and a modem processor that primarily processes wireless communication signals, such as a baseband processor. It will be appreciated that the modem processor described above may not be integrated into the processor 610.

Wherein, in the case that the terminal is a coding end device:

The processor 610 is configured to:

Optionally, the processor 610 is specifically configured to:

Optionally, the processor 610 is further configured to:

Wherein, in the case that the terminal is a decoding end device:

The processor 610 is configured to:

Optionally, the processor 610 is further configured to:

the processor 610 is specifically configured to:

Optionally, the processor 610 is specifically further configured to:

Optionally, the processor 610 is further configured to:

Specifically, the terminal according to the embodiment of the present application further includes instructions or programs stored in the memory 609 and capable of running on the processor 610, and the processor 610 invokes the instructions or programs in the memory 609 to execute the method executed by each module shown in fig. 12 or fig. 13, and achieve the same technical effects, so that repetition is avoided, and therefore, details are not repeated here.

The embodiment of the present application further provides a readable storage medium, where a program or an instruction is stored on the readable storage medium, where the program or the instruction implements each process of the foregoing three-dimensional grid encoding method embodiment when executed by a processor, or where the program or the instruction implements each process of the foregoing three-dimensional grid decoding method embodiment when executed by a processor, and the program or the instruction can achieve the same technical effect, so that repetition is avoided and no further description is given here.

Wherein the processor is a processor in the terminal described in the above embodiment. The readable storage medium includes a computer readable storage medium such as a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and the like.

The embodiment of the application further provides a chip, the chip comprises a processor and a communication interface, the communication interface is coupled with the processor, the processor is used for running programs or instructions, realizing the processes of the three-dimensional grid coding method embodiment, or realizing the processes of the three-dimensional grid decoding method embodiment, and achieving the same technical effects, and in order to avoid repetition, the description is omitted here.

It should be understood that the chips referred to in the embodiments of the present application may also be referred to as system-on-chip chips, or the like.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of the present application is not limited to performing the functions in the order shown or discussed, but may also include performing the functions in a substantially simultaneous manner or in an opposite order depending on the functions involved, e.g., the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a computer software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising instructions for causing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the method according to the embodiments of the present application.

The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are to be protected by the present application.

Claims

1. A three-dimensional trellis encoding method performed by an encoding end, comprising:

2. The method according to claim 1, wherein performing color space format conversion on the texture map in the first color space format of the three-dimensional grid to obtain the texture map in the second color space format comprises:

3. The method according to claim 2, wherein the method further comprises:

4. A method according to any one of claims 1 to 3, wherein the code stream corresponding to the three-dimensional grid includes a coding result of first indication information, where the first indication information is used to indicate whether the coding end performs color space format conversion on a texture map of the three-dimensional grid;

5. The method according to claim 4, wherein in case the first indication information indicates that a texture map of a three-dimensional mesh is color space format converted, the first indication information is further used to indicate a conversion type of the texture map of the three-dimensional mesh from the first color space format to the second color space format.

6. The method according to any of claims 1-5, wherein the amount of information relating to the color space of the texture map in the second color space format is smaller than the amount of information relating to the color space of the texture map in the first color space format.

7. The method of any of claims 1-6, wherein the second color space format and the first color space format are different color space formats of a color space or wherein the second color space format and the first color space format are different color space formats of a same color space.

8. The method according to any of claims 1-7, wherein the first color space format is an RGB color space format and the second color space format is a YUV color space format.

9. A three-dimensional trellis decoding method performed by a decoding side, comprising:

10. The method according to claim 9, wherein the method further comprises:

11. The method of claim 10, wherein performing color space format conversion on the texture map in the second color space format to obtain the texture map in the first color space format comprises:

12. The method according to claim 10 or 11, characterized in that the method further comprises:

13. The method according to any of claims 9-12, wherein the amount of information relating to the color space of the texture map in the second color space format is smaller than the amount of information relating to the color space of the texture map in the first color space format.

14. The method of any of claims 9-13, wherein the second color space format and the first color space format are different color space formats of a color space or wherein the second color space format and the first color space format are different color space formats of a same color space.

15. The method according to any of claims 9-14, wherein the first color space format is an RGB color space format and the second color space format is a YUV color space format.

16. A three-dimensional trellis encoding device, the device comprising:

17. A three-dimensional trellis decoding device, the device comprising:

18. An electronic device comprising a processor, a memory and a program or instruction stored on the memory and executable on the processor, the program or instruction when executed by the processor implementing the steps of the three-dimensional trellis encoding method of any one of claims 1 to 8, or the program or instruction when executed by the processor implementing the steps of the three-dimensional trellis decoding method of any one of claims 9 to 15.

19. A chip comprising a processor and a communication interface, the communication interface and the processor being coupled, the processor being configured to execute programs or instructions to implement the steps of the three-dimensional trellis encoding method of any of claims 1-8 or to implement the steps of the three-dimensional trellis decoding method of any of claims 9-15.

20. A readable storage medium, characterized in that the readable storage medium stores thereon a program or instructions which, when executed by a processor, implements the steps of the three-dimensional trellis encoding method of any one of claims 1 to 8, or which, when executed by a processor, implements the steps of the three-dimensional trellis decoding method of any one of claims 9 to 15.