Three-dimensional data encoding method, three-dimensional data decoding method, three-dimensional data encoding device, and three-dimensional data decoding device

Abstract

To reduce a processing amount.SOLUTION: A three-dimensional data encoding method includes: generating a data unit indicating a first data type; generating a data unit indicating a second data type; generating information indicating heads of the data units; generating a data unit including a first parameter to be used for encoding a data unit indicating a third data type; and generating a data unit indicating a fourth data type. The data unit indicating the first data type includes encoded position information, and the data unit indicating the second data type includes encoded attribute information corresponding to the encoded position information. The data unit indicating the third data type includes a first parameter to be used for decoding the data unit including the encoded position information, and the data unit indicating the fourth data type includes a second parameter to be used for decoding the data unit including the encoded attribute information.SELECTED DRAWING: Figure 64

Description

[Technical Field]

[0001] The present disclosure relates to a three-dimensional data encoding method, a three-dimensional data decoding method, a three-dimensional data encoding device, and a three-dimensional data decoding device. [Background technology]

[0002] In the future, devices and services that utilize 3D data are expected to become widespread in a wide range of fields, including computer vision for autonomous operation of automobiles or robots, map information, surveillance, infrastructure inspection, video distribution, etc. 3D data can be acquired in a variety of ways, including distance sensors such as range finders, stereo cameras, or a combination of multiple monocular cameras.

[0003] One method of representing three-dimensional data is a point cloud, which represents the shape of a three-dimensional structure using a group of points in three-dimensional space. A point cloud stores the position and color of the points. Point clouds are expected to become the mainstream method of representing three-dimensional data, but point clouds require a very large amount of data. Therefore, when storing or transmitting three-dimensional data, data compression through encoding is essential, just as with two-dimensional video images (examples include MPEG-4 AVC or HEVC standardized by MPEG).

[0004] In addition, compression of point clouds is partially supported by public libraries that perform point cloud-related processing (Point Cloud Library).

[0005] Furthermore, a technique is known in which three-dimensional map data is used to search for and display facilities located around a vehicle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 020663 Summary of the Invention [Problem to be solved by the invention]

[0007] In encoding and decoding of three-dimensional data, it is desirable to reduce the amount of processing.

[0008] An object of the present disclosure is to provide a three-dimensional data encoding method, a three-dimensional data decoding method, a three-dimensional data encoding device, or a three-dimensional data decoding device that can reduce the amount of processing. [Means for solving the problem]

[0009] A three-dimensional data encoding method according to one embodiment of the present disclosure generates a data unit indicating a first data type, generates a data unit indicating a second data type, generates a data unit indicating a third data type, generates a data unit indicating a fourth data type, and generates information indicating the beginning of each data unit, wherein the data unit indicating the first data type includes encoded position information, the data unit indicating the second data type includes encoded attribute information corresponding to the encoded position information, the data unit indicating the third data type includes a first parameter used in encoding the data unit including the encoded position information, and the data unit indicating the fourth data type includes a second parameter used in encoding the data unit including the encoded attribute information.

[0010] A three-dimensional data decoding method according to one embodiment of the present disclosure decodes data units indicating a first data type, decodes data units indicating a second data type, decodes data units indicating a third data type, and decodes data units indicating a fourth data type, and decodes information indicating the beginning of each data unit, wherein the data units indicating the first data type include encoded position information, the data units indicating the second data type include encoded attribute information corresponding to the encoded position information, the data units indicating the third data type include a first parameter used in decoding the data units including the encoded position information, and the data units indicating the fourth data type include a second parameter used in decoding the data units including the encoded attribute information. [Effects of the Invention]

[0011] The present disclosure can provide a three-dimensional data encoding method, a three-dimensional data decoding method, a three-dimensional data encoding device, or a three-dimensional data decoding device that can reduce the amount of processing. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a configuration of a three-dimensional data encoding / decoding system according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of point cloud data according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the structure of a data file in which point cloud data information according to the first embodiment is described. [Figure 4] FIG. 4 is a diagram showing types of point cloud data according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing a configuration of a first encoding unit according to the first embodiment. [Figure 6] FIG. 6 is a block diagram of a first encoding unit according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating a configuration of a first decoding unit according to the first embodiment. [Figure 8] FIG. 8 is a block diagram of a first decoding unit according to the first embodiment. [Figure 9] FIG. 9 is a diagram showing a configuration of a second encoding unit according to the first embodiment. [Figure 10] FIG. 10 is a block diagram of a second encoding unit according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating a configuration of a second decoding unit according to the first embodiment. [Figure 12] FIG. 12 is a block diagram of a second decoding unit according to the first embodiment. [Figure 13] FIG. 13 is a diagram showing a protocol stack related to PCC encoded data according to the first embodiment. [Figure 14] FIG. 14 is a diagram illustrating a protocol stack according to the first embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of the syntax of an NAL unit according to the first embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of the syntax of the NAL unit header according to the first embodiment. [Figure 17] FIG. 17 is a diagram illustrating an example of the semantics of pcc_codec_type according to the first embodiment. [Figure 18] FIG. 18 is a diagram illustrating an example of the semantics of pcc_nal_unit_type according to the first embodiment. [Figure 19] FIG. 19 is a flowchart of the encoding process according to the first embodiment. [Figure 20] FIG. 20 is a flowchart of the decoding process by the second decoding unit according to the first embodiment. [Figure 21] FIG. 21 is a flowchart of the decoding process by the first decoding unit according to the first embodiment. [Figure 22] FIG. 22 is a diagram illustrating a protocol stack according to the second embodiment. [Figure 23] FIG. 23 is a diagram illustrating an example of the syntax of an NAL unit for codec 2 according to the second embodiment. [Figure 24] FIG. 24 is a diagram illustrating an example of the syntax of a NAL unit header for codec 2 according to the second embodiment. [Figure 25] FIG. 25 illustrates an example of the semantics of codec2_nal_unit_type according to the second embodiment. [Figure 26] FIG. 26 is a diagram illustrating an example of the syntax of an NAL unit for codec 1 according to the second embodiment. [Figure 27] FIG. 27 is a diagram illustrating an example of the syntax of the NAL unit header for codec 1 according to the second embodiment. [Figure 28] FIG. 28 illustrates an example of the semantics of codec1_nal_unit_type according to the second embodiment. [Figure 29] FIG. 29 is a flowchart of the encoding process according to the second embodiment. [Figure 30] FIG. 30 is a flowchart of the decoding process according to the second embodiment. [Figure 31] FIG. 31 is a diagram illustrating a protocol stack according to the third embodiment. [Figure 32] FIG. 32 is a diagram illustrating an example of the syntax of an NAL unit according to the third embodiment. [Figure 33] FIG. 33 is a diagram illustrating an example of the syntax of a NAL unit header according to the third embodiment. [Figure 34] FIG. 34 is a diagram illustrating an example of the semantics of pcc_nal_unit_type according to the third embodiment. [Figure 35] FIG. 35 is a flowchart of the encoding process according to the third embodiment. [Figure 36] FIG. 36 is a flowchart of the decoding process according to the third embodiment. [Figure 37] FIG. 37 is a flowchart of an encoding process according to a modification of the embodiment. [Figure 38] FIG. 38 is a flowchart of a decoding process according to a modification of the embodiment. [Figure 39]FIG. 39 is a block diagram of an encoding unit according to the fourth embodiment. [Figure 40] FIG. 40 is a block diagram of a decoding unit according to the fourth embodiment. [Figure 41] FIG. 41 is a flowchart of the encoding process according to the fourth embodiment. [Figure 42] FIG. 42 is a flowchart of the decoding process according to the fourth embodiment. [Figure 43] FIG. 43 is a diagram illustrating the basic structure of the ISOBMFF according to the fifth embodiment. [Figure 44] FIG. 44 is a diagram illustrating a protocol stack according to the fifth embodiment. [Figure 45] FIG. 45 is a diagram showing an example in which NAL units according to the fifth embodiment are stored in a file for codec 1. [Figure 46] FIG. 46 is a diagram showing an example in which the NAL units according to the fifth embodiment are stored in a file for codec 2. In FIG. [Figure 47] FIG. 47 is a diagram illustrating a configuration of a first multiplexing unit according to the fifth embodiment. [Figure 48] FIG. 48 is a diagram illustrating a configuration of a first demultiplexing unit according to the fifth embodiment. [Figure 49] FIG. 49 is a diagram illustrating a configuration of a second multiplexing unit according to the fifth embodiment. [Figure 50] FIG. 50 is a diagram illustrating a configuration of a second demultiplexing unit according to the fifth embodiment. [Figure 51] FIG. 51 is a flowchart of processing by the first multiplexing unit according to the fifth embodiment. [Figure 52] FIG. 52 is a flowchart of processing by the second multiplexing unit according to the fifth embodiment. [Figure 53] FIG. 53 is a flowchart of processing by the first demultiplexing unit and the first decoding unit according to the fifth embodiment. [Figure 54] FIG. 54 is a flowchart of processing by the second demultiplexing unit and the second decoding unit according to the fifth embodiment. [Figure 55]FIG. 55 is a diagram showing the configurations of an encoding unit and a third multiplexing unit according to the sixth embodiment. In FIG. [Figure 56] FIG. 56 is a diagram illustrating a configuration of a third demultiplexing unit and a decoding unit according to the sixth embodiment. [Figure 57] FIG. 57 is a flowchart of processing by the third multiplexing unit according to the sixth embodiment. [Figure 58] FIG. 58 is a flowchart of processing by the third demultiplexing unit and decoding unit according to the sixth embodiment. [Figure 59] FIG. 59 is a flowchart of processing by the three-dimensional data storage device according to the sixth embodiment. [Figure 60] FIG. 60 is a flowchart of the processing performed by the three-dimensional data acquisition device according to the sixth embodiment. [Figure 61] FIG. 61 is a diagram illustrating the configurations of an encoding unit and a multiplexing unit according to the seventh embodiment. In FIG. [Figure 62] FIG. 62 is a diagram showing an example of a structure of coded data according to the seventh embodiment. [Figure 63] FIG. 63 is a diagram showing an example of the structure of coded data and NAL units according to the seventh embodiment. [Figure 64] FIG. 64 is a diagram illustrating an example of the semantics of pcc_nal_unit_type according to the seventh embodiment. [Figure 65] FIG. 65 is a diagram showing an example of the transmission order of NAL units according to the seventh embodiment. [Figure 66] FIG. 66 is a flowchart of processing by the three-dimensional data encoding device according to the seventh embodiment. [Figure 67] FIG. 67 is a flowchart of processing by the three-dimensional data decoding device according to the seventh embodiment. [Figure 68] FIG. 68 is a flowchart of the multiplexing process according to the seventh embodiment. [Figure 69] FIG. 69 is a flowchart of a demultiplexing process according to the seventh embodiment. [Figure 70]FIG. 70 is a flowchart of processing by the three-dimensional data encoding device according to the seventh embodiment. [Figure 71] FIG. 71 is a flowchart of processing by the three-dimensional data decoding device according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] A three-dimensional data encoding method according to one aspect of the present disclosure is a three-dimensional data encoding method for encoding time-series three-dimensional data, wherein the three-dimensional data includes position information and attribute information for each time, and the three-dimensional data encoding method encodes the position information and encodes the attribute information to be processed by referring to position information at the same time as the attribute information to be processed, and the position information and attribute information at the same time constitute an access unit.

[0014] According to this, the three-dimensional data encoding method can easily control references in encoding using access units, thereby reducing the amount of processing required for encoding.

[0015] For example, the three-dimensional data encoding method may further generate a bitstream including the encoded position information, the encoded attribute information, and information indicating the position information referenced by the attribute information to be processed.

[0016] For example, the bitstream may include a position parameter set including control information for position information at each time, and an attribute parameter set including control information for attribute information at each time.

[0017] For example, the bitstream may include a position sequence parameter set including control information common to position information at a plurality of times, and an attribute sequence parameter set including control information common to attribute information at a plurality of times.

[0018] For example, the bitstream may include a stream parameter set including control information common to position information of a plurality of times and attribute information of a plurality of times.

[0019] For example, the bitstream may include an access unit header that contains control information that is common within the access unit.

[0020] For example, a GOF (Group of Frames) consisting of one or more of the access units may be coded so that it can be decoded independently.

[0021] For example, the bitstream may include a GOF header that contains control information that is common within the GOF.

[0022] A three-dimensional data decoding method according to one aspect of the present disclosure is a three-dimensional data decoding method for decoding time-series three-dimensional data, wherein the three-dimensional data includes position information and attribute information for each time, and the position information and attribute information for the same time constitute an access unit, and the three-dimensional data decoding method decodes the position information from a bit stream, and decodes the attribute information to be processed from the bit stream by referring to the position information for the same time as the attribute information to be processed.

[0023] According to this, the three-dimensional data decoding method can easily control references in decoding using access units, thereby reducing the amount of processing required for decoding.

[0024] For example, the three-dimensional data decoding method may further acquire information indicating the location information of the reference destination of the attribute information to be processed from the bit stream, and decode the attribute information to be processed by referring to the location information of the reference destination indicated in the acquired information.

[0025] For example, the bitstream may include a position parameter set including control information for position information at each time, and an attribute parameter set including control information for attribute information at each time.

[0026] For example, the bitstream may include a position sequence parameter set including control information common to position information at a plurality of times, and an attribute sequence parameter set including control information common to attribute information at a plurality of times.

[0027] For example, the bitstream may include a stream parameter set including control information common to position information of a plurality of times and attribute information of a plurality of times.

[0028] For example, the bitstream may include an access unit header that contains control information that is common within the access unit.

[0029] For example, a group of frames (GOF) consisting of one or more of the access units may be decoded independently.

[0030] For example, the bitstream may include a GOF header that contains control information that is common within the GOF.

[0031] Furthermore, a three-dimensional data encoding device according to one aspect of the present disclosure is a three-dimensional data encoding device that encodes time-series three-dimensional data, and is equipped with a processor and a memory, wherein the three-dimensional data includes position information and attribute information for each time, and the processor uses the memory to encode the position information and encodes the attribute information to be processed by referring to position information at the same time as the attribute information to be processed, and the position information and attribute information at the same time constitute an access unit.

[0032] This allows the three-dimensional data encoding device to use the access unit to facilitate reference control during encoding, thereby reducing the amount of processing required for encoding.

[0033] Furthermore, a three-dimensional data decoding device according to one aspect of the present disclosure is a three-dimensional data decoding device that decodes time-series three-dimensional data, and is equipped with a processor and a memory, wherein the three-dimensional data includes position information and attribute information for each time, and the position information and attribute information for the same time constitute an access unit, and the processor uses the memory to decode the position information from the bit stream, and decodes the attribute information to be processed from the bit stream by referring to the position information for the same time as the attribute information to be processed.

[0034] This allows the three-dimensional data decoding device to use the access unit to facilitate reference control during decoding, thereby reducing the amount of decoding processing required by the three-dimensional data decoding device.

[0035] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0036] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in an independent claim that represents a superordinate concept will be described as optional components.

[0037] (Embodiment 1) When using encoded point cloud data in an actual device or service, it is desirable to transmit and receive the information required for the application in order to reduce network bandwidth. However, until now, such a function has not existed in the encoding structure of 3D data, and no encoding method for this purpose has existed.

[0038] In this embodiment, we will describe a three-dimensional data encoding method and a three-dimensional data encoding device that provide the function of transmitting and receiving information required for the purpose in encoded data of a three-dimensional point cloud, as well as a three-dimensional data decoding method and a three-dimensional data decoding device that decodes the encoded data, a three-dimensional data multiplexing method that multiplexes the encoded data, and a three-dimensional data transmission method that transmits the encoded data.

[0039] In particular, two encoding methods (encoding schemes) are currently being considered as encoding methods (encoding systems) for point cloud data; however, the structure of the encoded data and the method for storing the encoded data in a system format have not been defined, and as things stand, there is a problem that MUX processing (multiplexing) in the encoding unit, or transmission or storage, is not possible.

[0040] Furthermore, there has been no method to date that supports a format in which two codecs, a first encoding method and a second encoding method, are mixed, such as PCC (Point Cloud Compression).

[0041] In this embodiment, a description will be given of the structure of PCC encoded data in which two codecs, a first encoding method and a second encoding method, are mixed, and a method of storing the encoded data in a system format.

[0042] First, the configuration of a three-dimensional data (point cloud data) encoding / decoding system according to this embodiment will be described. Fig. 1 is a diagram showing an example of the configuration of a three-dimensional data encoding / decoding system according to this embodiment. As shown in Fig. 1, the three-dimensional data encoding / decoding system includes a three-dimensional data encoding system 4601, a three-dimensional data decoding system 4602, a sensor terminal 4603, and an external connection unit 4604.

[0043] The three-dimensional data encoding system 4601 generates encoded data or multiplexed data by encoding point cloud data, which is three-dimensional data. Note that the three-dimensional data encoding system 4601 may be a three-dimensional data encoding device realized by a single device, or may be a system realized by multiple devices. Furthermore, the three-dimensional data encoding device may include some of the multiple processing units included in the three-dimensional data encoding system 4601.

[0044] The three-dimensional data encoding system 4601 includes a point cloud data generation system 4611, a presentation unit 4612, an encoding unit 4613, a multiplexing unit 4614, an input / output unit 4615, and a control unit 4616. The point cloud data generation system 4611 includes a sensor information acquisition unit 4617 and a point cloud data generation unit 4618.

[0045] The sensor information acquisition unit 4617 acquires sensor information from the sensor terminal 4603 and outputs the sensor information to the point cloud data generation unit 4618. The point cloud data generation unit 4618 generates point cloud data from the sensor information and outputs the point cloud data to the encoding unit 4613.

[0046] The presentation unit 4612 presents the sensor information or point cloud data to the user. For example, the presentation unit 4612 displays information or an image based on the sensor information or point cloud data.

[0047] The encoding unit 4613 encodes (compresses) the point cloud data, and outputs the obtained encoded data, control information obtained in the encoding process, and other additional information to the multiplexing unit 4614. The additional information includes, for example, sensor information.

[0048] The multiplexing unit 4614 generates multiplexed data by multiplexing the coded data input from the coding unit 4613, the control information, and the additional information. The format of the multiplexed data is, for example, a file format for storage or a packet format for transmission.

[0049] The input / output unit 4615 (e.g., a communication unit or an interface) outputs the multiplexed data to the outside. Alternatively, the multiplexed data is stored in a storage unit such as an internal memory. The control unit 4616 (or application execution unit) controls each processing unit. In other words, the control unit 4616 controls encoding, multiplexing, etc.

[0050] The sensor information may be input to the encoding unit 4613 or the multiplexing unit 4614. The input / output unit 4615 may output the point cloud data or the encoded data directly to the outside.

[0051] The transmission signal (multiplexed data) output from the three-dimensional data encoding system 4601 is input to the three-dimensional data decoding system 4602 via the external connection unit 4604 .

[0052] The three-dimensional data decoding system 4602 generates point cloud data, which is three-dimensional data, by decoding the encoded data or multiplexed data. Note that the three-dimensional data decoding system 4602 may be a three-dimensional data decoding device realized by a single device, or may be a system realized by multiple devices. Furthermore, the three-dimensional data decoding device may include some of the multiple processing units included in the three-dimensional data decoding system 4602.

[0053] The three-dimensional data decoding system 4602 includes a sensor information acquisition unit 4621 , an input / output unit 4622 , a demultiplexing unit 4623 , a decoding unit 4624 , a presentation unit 4625 , a user interface 4626 , and a control unit 4627 .

[0054] The sensor information acquisition unit 4621 acquires sensor information from the sensor terminal 4603 .

[0055] The input / output unit 4622 acquires the transmission signal, decodes the multiplexed data (file format or packets) from the transmission signal, and outputs the multiplexed data to the demultiplexer 4623.

[0056] The demultiplexer 4623 obtains the coded data, control information, and additional information from the multiplexed data, and outputs the coded data, control information, and additional information to the decoder 4624.

[0057] The decoding unit 4624 reconstructs the point cloud data by decoding the encoded data.

[0058] The presentation unit 4625 presents the point cloud data to the user. For example, the presentation unit 4625 displays information or images based on the point cloud data. The user interface 4626 acquires instructions based on user operations. The control unit 4627 (or the application execution unit) controls each processing unit. In other words, the control unit 4627 controls demultiplexing, decoding, presentation, etc.

[0059] The input / output unit 4622 may acquire point cloud data or encoded data directly from the outside. The presentation unit 4625 may acquire additional information such as sensor information and present information based on the additional information. The presentation unit 4625 may perform presentation based on a user instruction acquired by the user interface 4626.

[0060] The sensor terminal 4603 generates sensor information, which is information obtained by a sensor. The sensor terminal 4603 is a terminal equipped with a sensor or a camera, and examples thereof include a moving body such as an automobile, a flying object such as an airplane, a mobile terminal, or a camera.

[0061] The sensor information that can be acquired by the sensor terminal 4603 includes, for example, (1) the distance between the sensor terminal 4603 and an object, or the reflectance of the object, obtained from a LIDAR, millimeter-wave radar, or infrared sensor, and (2) the distance between a camera and an object, or the reflectance of the object, obtained from multiple monocular camera images or stereo camera images. The sensor information may also include the attitude, direction, gyro (angular velocity), position (GPS information or altitude), speed, acceleration, etc. of the sensor. The sensor information may also include temperature, air pressure, humidity, magnetism, etc.

[0062] The external connection unit 4604 is realized by an integrated circuit (LSI or IC), an external storage unit, communication with a cloud server via the Internet, broadcasting, or the like.

[0063] Next, point cloud data will be described. Fig. 2 is a diagram showing the configuration of point cloud data. Fig. 3 is a diagram showing an example of the configuration of a data file in which information about point cloud data is written.

[0064] Point cloud data includes data on multiple points. The data on each point includes location information (three-dimensional coordinates) and attribute information for that location information. A collection of multiple points is called a point cloud. For example, a point cloud can represent the three-dimensional shape of an object.

[0065] Position information such as three-dimensional coordinates is sometimes called geometry. Data for each point may also include attribute information of multiple attribute types. Attribute types include, for example, color or reflectance.

[0066] One piece of attribute information may be associated with one piece of location information, or multiple pieces of attribute information with different attribute types may be associated with one piece of location information, or multiple pieces of attribute information of the same attribute type may be associated with one piece of location information.

[0067] The configuration example of the data file shown in FIG. 3 is an example in which there is a one-to-one correspondence between position information and attribute information, and shows the position information and attribute information of N points that make up the point cloud data.

[0068] The position information is, for example, information on the three axes x, y, and z. The attribute information is, for example, RGB color information. A typical data file is a ply file.

[0069] Next, the types of point cloud data will be explained. Fig. 4 is a diagram showing the types of point cloud data. As shown in Fig. 4, point cloud data includes static objects and dynamic objects.

[0070] A static object is 3D point cloud data at any time (a certain time). A dynamic object is 3D point cloud data that changes over time. Hereinafter, 3D point cloud data at a certain time will be referred to as a PCC frame, or simply a frame.

[0071] The object may be a point cloud with a certain area restriction, such as ordinary video data, or a large-scale point cloud with no area restriction, such as map information.

[0072] Furthermore, there may be point cloud data of various densities, such as sparse point cloud data and dense point cloud data.

[0073] Each processing unit will be described in detail below. Sensor information is acquired by various methods, such as a distance sensor such as a LIDAR or a range finder, a stereo camera, or a combination of multiple monocular cameras. The point cloud data generation unit 4618 generates point cloud data based on the sensor information acquired by the sensor information acquisition unit 4617. The point cloud data generation unit 4618 generates position information as point cloud data, and adds attribute information for the position information to the position information.

[0074] The point cloud data generation unit 4618 may process the point cloud data when generating position information or adding attribute information. For example, the point cloud data generation unit 4618 may reduce the amount of data by deleting point clouds with overlapping positions. In addition, the point cloud data generation unit 4618 may convert (position shift, rotation, normalization, etc.) the position information or render the attribute information.

[0075] In FIG. 1, the point cloud data generation system 4611 is included in the three-dimensional data encoding system 4601, but it may be provided independently outside the three-dimensional data encoding system 4601.

[0076] The encoding unit 4613 generates encoded data by encoding the point cloud data based on a predetermined encoding method. There are two main types of encoding methods: the first is an encoding method that uses position information, and this encoding method will be referred to as the first encoding method hereinafter; and the second is an encoding method that uses a video codec, and this encoding method will be referred to as the second encoding method hereinafter.

[0077] The decoding unit 4624 decodes the coded data based on a predetermined coding method to decode the point group data.

[0078] The multiplexing unit 4614 generates multiplexed data by multiplexing the encoded data using an existing multiplexing method. The generated multiplexed data is transmitted or stored. In addition to the PCC encoded data, the multiplexing unit 4614 multiplexes other media such as video, audio, subtitles, applications, and files, or reference time information. The multiplexing unit 4614 may also multiplex attribute information related to sensor information or point cloud data.

[0079] Multiplexing methods or file formats include ISOBMFF, MPEG-DASH, which is an ISOBMFF-based transmission method, MMT, MPEG-2 TS Systems, and RMP.

[0080] The demultiplexer 4623 extracts PCC encoded data, other media, time information, and the like from the multiplexed data.

[0081] The input / output unit 4615 transmits the multiplexed data using a method suited to the transmission medium or storage medium, such as broadcasting or communication. The input / output unit 4615 may communicate with other devices via the Internet, or may communicate with a storage unit such as a cloud server.

[0082] The communication protocol used may be http, ftp, TCP, UDP, etc. A PULL type communication method or a PUSH type communication method may be used.

[0083] Either wired or wireless transmission may be used. For wired transmission, Ethernet (registered trademark), USB, RS-232C, HDMI (registered trademark), coaxial cable, etc. are used. For wireless transmission, wireless LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), millimeter waves, etc. are used.

[0084] As a broadcasting system, for example, DVB-T2, DVB-S2, DVB-C2, ATSC3.0, or ISDB-S3 is used.

[0085] Fig. 5 is a diagram showing the configuration of a first encoding unit 4630, which is an example of the encoding unit 4613 that performs encoding using the first encoding method. Fig. 6 is a block diagram of the first encoding unit 4630. The first encoding unit 4630 generates encoded data (encoded stream) by encoding point cloud data using the first encoding method. This first encoding unit 4630 includes a position information encoding unit 4631, an attribute information encoding unit 4632, an additional information encoding unit 4633, and a multiplexing unit 4634.

[0086] The first encoding unit 4630 is characterized in that it performs encoding taking into consideration a three-dimensional structure. The first encoding unit 4630 is also characterized in that the attribute information encoding unit 4632 performs encoding using information obtained from the position information encoding unit 4631. The first encoding method is also called GPCC (Geometry based PCC).

[0087] The point cloud data is PCC point cloud data such as a PLY file, or PCC point cloud data generated from sensor information, and includes position information (Position), attribute information (Attribute), and other additional information (MetaData). The position information is input to a position information encoder 4631, the attribute information is input to an attribute information encoder 4632, and the additional information is input to an additional information encoder 4633.

[0088] The position information encoding unit 4631 encodes the position information to generate encoded position information (Compressed Geometry), which is encoded data. For example, the position information encoding unit 4631 encodes the position information using an N-ary tree structure such as an octree. Specifically, in an octree, the target space is divided into eight nodes (subspaces), and 8-bit information (occupancy code) indicating whether or not a point cloud is included in each node is generated. Furthermore, the node including the point cloud is further divided into eight nodes, and 8-bit information indicating whether or not a point cloud is included in each of the eight nodes is generated. This process is repeated until the number of point clouds included in a predetermined layer or node falls below a threshold.

[0089] The attribute information encoding unit 4632 generates encoded attribute information (Compressed Attribute) that is encoded data by encoding using the configuration information generated by the position information encoding unit 4631. For example, the attribute information encoding unit 4632 determines a reference point (reference node) to be referenced when encoding a target point (target node) to be processed, based on the octree structure generated by the position information encoding unit 4631. For example, the attribute information encoding unit 4632 references a peripheral node or adjacent node whose parent node in the octree is the same as that of the target node. Note that the method of determining the reference relationship is not limited to this.

[0090] Furthermore, the encoding process of the attribute information may include at least one of a quantization process, a prediction process, and an arithmetic coding process. In this case, the reference means using a reference node to calculate a predicted value of the attribute information, or using the state of the reference node (e.g., occupancy information indicating whether the reference node includes a point group) to determine an encoding parameter. For example, the encoding parameter is a quantization parameter in a quantization process, or a context in an arithmetic coding process.

[0091] The additional information encoding unit 4633 generates encoded additional information (Compressed MetaData) that is encoded data by encoding compressible data from the additional information.

[0092] The multiplexing unit 4634 multiplexes the encoding position information, the encoding attribute information, the encoding additional information, and other additional information to generate a compressed stream, which is encoded data. The generated compressed stream is output to a processing unit in a system layer (not shown).

[0093] Next, a first decoding unit 4640, which is an example of the decoding unit 4624 that performs decoding using the first encoding method, will be described. FIG. 7 is a diagram showing the configuration of the first decoding unit 4640. FIG. 8 is a block diagram of the first decoding unit 4640. The first decoding unit 4640 generates point cloud data by decoding, using the first encoding method, coded data (coded stream) coded using the first coding method. The first decoding unit 4640 includes a demultiplexing unit 4641, a position information decoding unit 4642, an attribute information decoding unit 4643, and an additional information decoding unit 4644.

[0094] A coded stream (compressed stream) that is coded data is input to the first decoding unit 4640 from a processing unit in a system layer (not shown).

[0095] The demultiplexer 4641 separates the encoded position information (Compressed Geometry), the encoded attribute information (Compressed Attribute), the encoded additional information (Compressed MetaData), and other additional information from the encoded data.

[0096] The position information decoding unit 4642 generates position information by decoding the encoded position information. For example, the position information decoding unit 4642 restores the position information of a point group represented by three-dimensional coordinates from the encoded position information represented by an N-ary tree structure such as an octree.

[0097] The attribute information decoding unit 4643 decodes the encoded attribute information based on the configuration information generated by the position information decoding unit 4642. For example, the attribute information decoding unit 4643 determines a reference point (reference node) to be referenced in decoding the target point (target node) to be processed based on the octree structure obtained by the position information decoding unit 4642. For example, the attribute information decoding unit 4643 references a peripheral node or adjacent node whose parent node in the octree is the same as that of the target node. Note that the method of determining the reference relationship is not limited to this.

[0098] Furthermore, the attribute information decoding process may include at least one of an inverse quantization process, a prediction process, and an arithmetic decoding process. In this case, the reference means using a reference node to calculate a predicted value of the attribute information, or using the state of the reference node (e.g., occupancy information indicating whether the reference node includes a point group) to determine a decoding parameter. For example, the decoding parameter is a quantization parameter in an inverse quantization process, or a context in an arithmetic decoding process.

[0099] The additional information decoding unit 4644 generates additional information by decoding the encoded additional information. The first decoding unit 4640 uses the additional information necessary for decoding the position information and attribute information during decoding, and outputs the additional information necessary for the application to the outside.

[0100] Next, a description will be given of second encoding unit 4650, which is an example of encoding unit 4613 that performs encoding using the second encoding method. Fig. 9 is a diagram showing the configuration of second encoding unit 4650. Fig. 10 is a block diagram of second encoding unit 4650.

[0101] The second encoding unit 4650 generates encoded data (encoded stream) by encoding the point cloud data using a second encoding method. The second encoding unit 4650 includes an additional information generation unit 4651, a position image generation unit 4652, an attribute image generation unit 4653, a video encoding unit 4654, an additional information encoding unit 4655, and a multiplexing unit 4656.

[0102] The second encoding unit 4650 has a feature of generating a position image and an attribute image by projecting a three-dimensional structure onto a two-dimensional image, and encoding the generated position image and attribute image using an existing video encoding method. The second encoding method is also called VPCC (Video based PCC).

[0103] The point cloud data is PCC point cloud data such as a PLY file, or PCC point cloud data generated from sensor information, and includes position information (Position), attribute information (Attribute), and other additional information (MetaData).

[0104] The additional information generating unit 4651 generates map information of a plurality of two-dimensional images by projecting a three-dimensional structure onto the two-dimensional images.

[0105] The position image generation unit 4652 generates a position image (Geometry Image) based on the position information and the map information generated by the additional information generation unit 4651. This position image is, for example, a distance image in which distance (Depth) is indicated as a pixel value. Note that this distance image may be an image in which multiple point clouds are viewed from a single viewpoint (an image in which multiple point clouds are projected onto a single two-dimensional plane), or may be multiple images in which multiple point clouds are viewed from multiple viewpoints, or may be a single image in which these multiple images are integrated.

[0106] The attribute image generation unit 4653 generates an attribute image based on the attribute information and the map information generated by the additional information generation unit 4651. This attribute image is, for example, an image in which attribute information (for example, color (RGB)) is represented as pixel values. Note that this image may be an image in which multiple point clouds are viewed from one viewpoint (an image in which multiple point clouds are projected onto one two-dimensional plane), or multiple images in which multiple point clouds are viewed from multiple viewpoints, or a single image in which these multiple images are integrated.

[0107] The video encoding unit 4654 generates an encoded position image (Compressed Geometry Image) and an encoded attribute image (Compressed Attribute Image), which are encoded data, by encoding the position image and the attribute image using a video encoding method. Note that any known encoding method may be used as the video encoding method. For example, the video encoding method is AVC, HEVC, or the like.

[0108] The additional information encoding unit 4655 generates encoded additional information (Compressed MetaData) by encoding the additional information, map information, and the like included in the point cloud data.

[0109] The multiplexing unit 4656 multiplexes the encoding position image, the encoding attribute image, the encoding additional information, and other additional information to generate an encoded stream (Compressed Stream) that is encoded data. The generated encoded stream is output to a processing unit in a system layer (not shown).

[0110] Next, a second decoding unit 4660, which is an example of the decoding unit 4624 that performs decoding using the second encoding method, will be described. FIG. 11 is a diagram showing the configuration of the second decoding unit 4660. FIG. 12 is a block diagram of the second decoding unit 4660. The second decoding unit 4660 generates point cloud data by decoding, using the second encoding method, coded data (coded stream) coded using the second coding method. The second decoding unit 4660 includes a demultiplexing unit 4661, a video decoding unit 4662, an additional information decoding unit 4663, a position information generation unit 4664, and an attribute information generation unit 4665.

[0111] A coded stream (compressed stream) that is coded data is input to the second decoding unit 4660 from a processing unit in a system layer (not shown).

[0112] The demultiplexer 4661 separates the encoded position image (Compressed Geometry Image), the encoded attribute image (Compressed Attribute Image), the encoded additional information (Compressed MetaData), and other additional information from the encoded data.

[0113] The video decoding unit 4662 generates a position image and an attribute image by decoding the encoded position image and the encoded attribute image using a video encoding method. Note that any known encoding method may be used as the video encoding method. For example, the video encoding method may be AVC or HEVC.

[0114] The additional information decoding unit 4663 decodes the encoded additional information to generate additional information including map information and the like.

[0115] The position information generating unit 4664 generates position information using the position image and map information. The attribute information generating unit 4665 generates attribute information using the attribute image and map information.

[0116] The second decoding unit 4660 uses the additional information necessary for decoding during decoding, and outputs the additional information necessary for the application to the outside.

[0117] The following describes the problems with the PCC encoding method. Fig. 13 is a diagram showing a protocol stack related to PCC encoded data. Fig. 13 shows an example in which other media data such as video (e.g., HEVC) or audio is multiplexed onto the PCC encoded data and transmitted or stored.

[0118] Multiplexing methods and file formats have the function of multiplexing various coded data and transmitting or storing them. To transmit or store coded data, the coded data must be converted into the format of the multiplexing method. For example, HEVC specifies a technology that stores coded data in a data structure called a NAL unit and stores the NAL unit in ISOBMFF.

[0119] On the other hand, currently, a first encoding method (Codec1) and a second encoding method (Codec2) are being considered as methods for encoding point cloud data, but the structure of the encoded data and the method for storing the encoded data in a system format have not been defined, which poses the problem that, as it stands, it is not possible to perform MUX processing (multiplexing) in the encoding unit, transmission, or storage.

[0120] In the following description, unless a specific encoding method is specified, it refers to either the first encoding method or the second encoding method.

[0121] A method for defining NAL units according to this embodiment will be described below. For example, in conventional codecs such as HEVC, one format of NAL units is defined for one codec. However, there has been no method so far to support a format in which two codecs, a first encoding method and a second encoding method (hereinafter referred to as PCC codec), are mixed, as in PCC.

[0122] In this embodiment, a format common to all PCC codecs is defined as an NAL unit, and an identifier of an NAL unit dependent on the PCC codec is further defined. Fig. 14 is a diagram showing a protocol stack in this case. Figs. 15 to 17 are diagrams showing examples of NAL unit formats common to all codecs. Fig. 15 is a diagram showing an example of the syntax of a Common PCC NAL Unit. Fig. 16 is a diagram showing an example of the syntax of a Common PCC NAL Unit Header. Fig. 17 is a diagram showing an example of the semantics of pcc_codec_type. Fig. 18 is a diagram showing an example of a codec-dependent NAL unit type definition, and is a diagram showing an example of the semantics of pcc_nal_unit_type.

[0123] A NAL unit format common to all PCC codecs is defined. The NAL unit (pcc_nal_unit) includes a header (pcc_nal_unit_header), a payload (pcc_nal_unit_payload), and trailing bits (trailing_bits). The same format is used when storing data for either the first or second encoding method.

[0124] The NAL unit header (pcc_nal_unit_header) stores a codec type (pcc_codec_type) and a NAL unit type (pcc_nal_unit_type). The codec type indicates whether the PCC codec of the coded data stored in the NAL unit is a first coding method or a second coding method.

[0125] The NAL unit type indicates the type of the NAL unit depending on the codec, and types are defined for each codec. If the codec type is a first encoding method, the NAL unit type indicates the NAL unit type defined for the first encoding method. If the codec type is a second encoding method, the NAL unit type indicates the NAL unit type defined for the second encoding method. In other words, the NAL unit type defined for the first encoding method and the NAL unit type defined for the second encoding method have different meanings associated with the same value.

[0126] Note that in the header, the codec type function may be merged into the NAL unit type, for example, the codec type may be indicated using part of the information of the NAL unit type.

[0127] Next, the encoding process according to this embodiment will be described. Fig. 19 is a flowchart of the encoding process according to this embodiment. The process in this figure shows the process of the first encoding unit 4630 or the second encoding unit 4650 when the above definitions are used. Note that, hereinafter, the first encoding unit 4630 and the second encoding unit 4650 will also be referred to as the encoding unit 4613 without any distinction. Furthermore, the process in this figure is mainly performed by the multiplexing unit 4634 shown in Fig. 6 or the multiplexing unit 4656 shown in Fig. 10.

[0128] The process in the figure shows an example in which PCC data is encoded using either the first encoding method or the second encoding method, and it is assumed that which PCC codec is used for encoding is known. For example, which PCC codec is used may be specified by a user or an external device.

[0129] First, the encoding unit 4613 encodes the PCC data using a codec of either the first encoding method or the second encoding method (S4601).

[0130] If the codec used is the second encoding method (second encoding method in S4602), the encoding unit 4613 sets pcc_codec_type included in the NAL unit header to a value indicating that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4603). The encoding unit 4613 also sets pcc_nal_unit_type in the NAL unit header to an identifier of the NAL unit for the second encoding method (S4604). The encoding unit 4613 then generates a NAL unit that has the set NAL unit header and includes encoded data in its payload. The encoding unit 4613 then transmits the generated NAL unit (S4605).

[0131] On the other hand, if the codec used is the first encoding method (first encoding method in S4602), the encoding unit 4613 sets pcc_codec_type in the NAL unit header to a value indicating that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4606). The encoding unit 4613 also sets pcc_nal_unit_type in the NAL unit header to an identifier of the NAL unit for the first encoding method (S4607). The encoding unit 4613 then generates a NAL unit that has the set NAL unit header and includes encoded data in its payload. The encoding unit 4613 then transmits the generated NAL unit (S4605).

[0132] Note that in steps S4603 and S4606, if the function of pcc_code_type is included in pcc_nal_unit_type, the encoding unit 4613 may indicate in pcc_nal_unit_type whether the NAL unit is encoded using the first encoding method or the second encoding method.

[0133] Next, the decoding process by first decoding section 4640 and second decoding section 4660 according to this embodiment will be described. Fig. 20 is a flowchart showing the decoding process by second decoding section 4660. The process in this figure is mainly performed by demultiplexing section 4661 shown in Fig. 12.

[0134] Note that the process in this figure shows an example in which PCC data is encoded using either the second encoding method or the first encoding method. In this method, the demultiplexer 4661 included in the second decoder 4660 can identify the codec type of the NAL unit by referencing information included in the NAL unit header. Therefore, the demultiplexer 4661 can output the necessary information to the video decoder 4662 according to the codec type.

[0135] First, the second decoding unit 4660 receives an NAL unit (S4611). For example, this NAL unit is generated by the processing in the encoding unit 4613 described above. That is, the header of this NAL unit includes pcc_codec_type and pcc_nal_unit_type.

[0136] Next, the second decoding unit 4660 determines whether the pcc_codec_type included in the NAL unit header indicates the first encoding method or the second encoding method (S4612).

[0137] If pcc_codec_type indicates the second encoding method (second encoding method in S4612), the second decoding unit 4660 determines that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4613).The second decoding unit 4660 then identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the second encoding method (S4614).The second decoding unit 4660 then decodes the PCC data using the decoding process of the second encoding method (S4615).

[0138] On the other hand, if pcc_codec_type indicates the first encoding method (first encoding method in S4612), the second decoding unit 4660 determines that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4616). In this case, the second decoding unit 4660 does not process the NAL unit (S4617).

[0139] In addition, in step S4612, if the function of pcc_code_type is included in pcc_nal_unit_type, the second decoding unit 4660 may refer to pcc_nal_unit_type to determine whether the codec used for the data included in the NAL unit is the first encoding method or the second encoding method.

[0140] 21 is a flowchart showing the decoding process by the first decoding unit 4640. The process in this figure is mainly performed by the demultiplexing unit 4641 shown in FIG.

[0141] Note that the process in this figure shows an example in which PCC data is encoded using either the first encoding method or the second encoding method. In this method, the demultiplexing unit 4641 included in the first decoding unit 4640 can identify the codec type of the NAL unit by referencing information included in the NAL unit header. Therefore, the demultiplexing unit 4641 can output the necessary information according to the codec type to the position information decoding unit 4642 and the attribute information decoding unit 4643.

[0142] First, the first decoding unit 4640 receives an NAL unit (S4621). For example, this NAL unit is generated by the processing in the encoding unit 4613. That is, the header of this NAL unit includes pcc_codec_type and pcc_nal_unit_type.

[0143] Next, the first decoding unit 4640 determines whether pcc_codec_type included in the NAL unit header indicates the first encoding method or the second encoding method (S4622).

[0144] If pcc_codec_type indicates the second encoding method (second encoding method in S4622), the first decoding unit 4640 determines that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4623). In this case, the first decoding unit 4640 does not process the NAL unit (S4624).

[0145] On the other hand, if pcc_codec_type indicates the first encoding method (first encoding method in S4622), the first decoding unit 4640 determines that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4625).The first decoding unit 4640 then identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the first encoding method (S4626).The first decoding unit 4640 then decodes the PCC data using the decoding process of the first encoding method (S4627).

[0146] (Embodiment 2) In this embodiment, another method for defining NAL units will be described. In this embodiment, a different format for NAL units is defined for each PCC codec. Furthermore, an identifier for the NAL unit is defined independently for each PCC codec.

[0147] Fig. 22 is a diagram showing a protocol stack in this case. Fig. 23 is a diagram showing an example of the syntax of a NAL unit for codec 2 (codec2_nal_unit). Fig. 24 is a diagram showing an example of the syntax of a NAL unit header for codec 2 (codec2_nal_unit_header). Fig. 25 is a diagram showing an example of the semantics of codec2_nal_unit_type.

[0148] Fig. 26 is a diagram illustrating an example of the syntax of a NAL unit (codec1_nal_unit) for codec 1. Fig. 27 is a diagram illustrating an example of the syntax of a NAL unit header (codec1_nal_unit_header) for codec 1. Fig. 28 is a diagram illustrating an example of the semantics of codec1_nal_unit_type.

[0149] The NAL unit format is defined independently for each PCC codec. The NAL unit (codec1_nal_unit, codec2_nal_unit) includes a header (codec1_nal_unit_header, codec2_nal_unit_header), a payload (codec1_nal_unit_payload, codec2_nal_unit_payload), and trailing bits (trailing_bits). The NAL unit (codec1_nal_unit) for the first encoding method and the NAL unit (codec2_nal_unit) for the second encoding method may have the same structure or different structures. The NAL unit for the first encoding method and the NAL unit for the second encoding method may have different sizes.

[0150] Data encoded using a first encoding method is stored in NAL units for the first encoding method, and data encoded using a second encoding method is stored in NAL units for the second encoding method.

[0151] The NAL unit headers (codec1_nal_unit_header, codec2_nal_unit_header) store NAL unit types (codec1_nal_unit_type, codec2_nal_unit_type). NAL unit types are independent for each codec, and types are defined for each codec. That is, the NAL unit for a first encoding method describes the NAL unit type defined for the first encoding method. The NAL unit for a second encoding method describes the NAL unit type defined for the second encoding method.

[0152] By using this method, the first encoding method and the second encoding method can be treated as different codecs.

[0153] Next, the encoding process according to this embodiment will be described. Fig. 29 is a flowchart of the encoding process according to this embodiment. The process in this figure shows the process of the first encoding unit 4630 or the second encoding unit 4650 when the above definitions are used. Furthermore, the process in this figure is mainly performed by the multiplexing unit 4634 shown in Fig. 6 or the multiplexing unit 4656 shown in Fig. 10.

[0154] The process in the figure shows an example in which PCC data is encoded using either the first encoding method or the second encoding method, and it is assumed that which PCC codec is used for encoding is known. For example, which PCC codec is used may be specified by a user or an external device.

[0155] First, the encoding unit 4613 encodes the PCC data using a codec of either the first encoding method or the second encoding method (S4631).

[0156] If the codec used is the second encoding method (second encoding method in S4632), the encoding unit 4613 generates a NAL unit in the NAL unit format for the second encoding method (S4633). Next, the encoding unit 4613 sets an identifier of the NAL unit for the second encoding method to codec2_nal_unit_type included in the NAL unit header (S4634). Then, the encoding unit 4613 generates a NAL unit that has the set NAL unit header and includes encoded data in its payload. Then, the encoding unit 4613 transmits the generated NAL unit (S4635).

[0157] On the other hand, if the codec used is the first encoding method (first encoding method in S4632), the encoding unit 4613 generates a NAL unit in the NAL unit format for the first encoding method (S4636). Next, the encoding unit 4613 sets the identifier of the NAL unit for the first encoding method to codec1_nal_unit_type in the NAL unit header (S4637). Then, the encoding unit 4613 generates a NAL unit that has the set NAL unit header and includes encoded data in its payload. Then, the encoding unit 4613 transmits the generated NAL unit (S4635).

[0158] Next, the decoding process according to this embodiment will be described. Fig. 30 is a flowchart of the decoding process according to this embodiment. The process in this figure shows the process of the first decoding unit 4640 or the second decoding unit 4660 when the above definitions are used. Note that, hereinafter, the first decoding unit 4640 and the second decoding unit 4660 will also be referred to as the decoding unit 4624 without any distinction. Furthermore, the process in this figure is mainly performed by the demultiplexing unit 4641 shown in Fig. 8 or the demultiplexing unit 4661 shown in Fig. 12.

[0159] Note that the process in the figure shows an example in which PCC data is encoded using either the first encoding method or the second encoding method, and it is assumed that which PCC codec is used for encoding is known. For example, information indicating the codec used is included in the transmission signal, multiplexed data, or encoded data, and the decoding unit 4624 determines the codec used by referring to this information. Note that the decoding unit 4624 may also determine the codec used based on a signal obtained separately from these signals.

[0160] If the codec used is the second encoding method (second encoding method in S4641), the decoding unit 4624 receives an NAL unit in the format for the second encoding method (S4642). Next, the decoding unit 4624 determines that the NAL unit is for the second encoding method and identifies the data using the NAL unit format for the second encoding method and the codec2_nal_unit_type for the second encoding method (S4643). Next, the decoding unit 4624 decodes the PCC data using the decoding process for the second encoding method (S4644).

[0161] On the other hand, if the codec used is the first encoding method (first encoding method in S4641), the decoding unit 4624 receives an NAL unit in the format for the first encoding method (S4645). Next, the decoding unit 4624 determines that the NAL unit is for the first encoding method and identifies the data using the NAL unit format for the first encoding method and codec1_nal_unit_type for the first encoding method (S4646). Next, the decoding unit 4624 decodes the PCC data using the decoding process for the first encoding method (S4747).

[0162] (Embodiment 3) In this embodiment, another method for defining NAL units will be described. In this embodiment, a format common to PCC codecs is defined as an NAL unit. Also, an identifier of the NAL unit common to PCC codecs is defined.

[0163] Fig. 31 is a diagram showing a protocol stack in this case. Figs. 32 to 34 are diagrams showing examples of NAL unit formats common to codecs. Fig. 32 is a diagram showing an example of the syntax of a Common PCC NAL Unit. Fig. 33 is a diagram showing an example of the syntax of a Common PCC NAL Unit Header. Fig. 34 is a diagram showing an example of the semantics of pcc_codec_type.

[0164] A NAL unit format common to all PCC codecs is defined. The NAL unit (pcc_nal_unit) includes a header (pcc_nal_unit_header), a payload (pcc_nal_unit_payload), and trailing bits (trailing_bits). The same format is used whether data of the first or second encoding method is stored.

[0165] The NAL unit header (pcc_nal_unit_header) stores the NAL unit type (pcc_nal_unit_type). The NAL unit type is common to all codecs, and a type common to all codecs is defined. That is, a commonly defined NAL unit type is written in both the NAL unit for the first encoding method and the NAL unit for the second encoding method. In the example shown in Fig. 34, for example, PCC DataA is coded data of codec 1, PCC DataB is coded data of codec 2, PCC MetaDataA is additional information of codec 1, and PCC MetaDataB is additional information of codec 2.

[0166] By using this method, the first encoding method and the second encoding method can be treated as the same codec.

[0167] Next, the encoding process according to this embodiment will be described. Fig. 35 is a flowchart of the encoding process according to this embodiment. The process in this figure shows the process of the first encoding unit 4630 or the second encoding unit 4650 when the above definitions are used. Furthermore, the process in this figure is mainly performed by the multiplexing unit 4634 shown in Fig. 6 or the multiplexing unit 4656 shown in Fig. 10.

[0168] The process in the figure shows an example in which PCC data is encoded using either the second encoding method or the first encoding method, and it is assumed that which PCC codec is used for encoding is known. For example, which PCC codec is used may be specified by a user or an external device.

[0169] First, the encoding unit 4613 encodes the PCC data using a codec of either the second encoding method or the first encoding method (S4651). Next, the encoding unit 4613 generates an NAL unit in a PCC common NAL unit format (S4652).

[0170] Next, the encoding unit 4613 sets a PCC-common NAL unit identifier to pcc_nal_unit_type included in the NAL unit header (S4653), and then transmits the NAL unit that has the set NAL unit header and includes encoded data in its payload (S4654).

[0171] Next, the decoding process according to this embodiment will be described. Fig. 36 is a flowchart of the decoding process according to this embodiment. The process in this figure shows the process of the first decoding unit 4640 or the second decoding unit 4660 when the above definitions are used. The process in this figure is mainly performed by the demultiplexing unit 4641 shown in Fig. 8 or the demultiplexing unit 4661 shown in Fig. 12.

[0172] The process in FIG. 10 shows an example in which PCC data is encoded using either the second encoding method or the first encoding method.

[0173] First, the decoding unit 4624 determines the codec used to encode the data included in the NAL unit (S4661). For example, the decoding unit 4624 determines the codec used by referring to pcc_nal_unit_type included in the NAL unit header.

[0174] If the codec used is the second encoding method (second encoding method in S4661), the decoding unit 4624 receives NAL units in a format common to PCCs (S4662). Next, the decoding unit 4624 determines that the NAL units are common and identifies the data using the common NAL unit format and common pcc_nal_unit_type (S4663). Next, the decoding unit 4624 decodes the PCC data using the decoding process of the second encoding method (S4664).

[0175] On the other hand, if the codec used is the first encoding method (first encoding method in S4661), the decoding unit 4624 receives NAL units in a format common to PCCs (S4665). Next, the decoding unit 4624 determines that the NAL units are common and identifies the data using the common NAL unit format and common pcc_nal_unit_type (S4666). Next, the decoding unit 4624 decodes the PCC data using the decoding process of the first encoding method (S4667).

[0176] The following describes modifications of the above-mentioned Embodiments 1 to 3. As another method for indicating the PCC codec type, the following method may be used.

[0177] In the first, second, and third embodiments, a case where two codecs, a first encoding method and a second encoding method, are mixed is described, but the above method can also be applied when there are three or more PCC codecs.

[0178] In addition, in embodiments 1 and 3, the PCC codec identification information (pcc_codec_type in embodiment 1 and pcc_nal_unit_type in embodiment 3b) is described in the NAL unit header, but the codec identification information may also be stored in another location.

[0179] Furthermore, the first encoding method and the second encoding method are not limited to the above examples and may be any codec. For example, the first encoding method and the second encoding method may be a plurality of codecs obtained by subdividing GPCC, or a plurality of codecs obtained by subdividing VPCC. For example, the first encoding method and the second encoding method may both be VPCC but use different video encoding methods. The video encoding method may be, for example, AVC or HEVC. Furthermore, either or both of the first encoding method and the second encoding method may be an encoding method including other encoding methods, such as for video, audio, or text applications.

[0180] For example, the codec identification information may be included in control information included in a PCC encoded stream, where the control information is, for example, a parameter set or metadata such as SEI (Supplemental Enhancement Information).

[0181] 37 is a flowchart of the encoding process by the encoding unit 4613 in this case. First, the encoding unit 4613 encodes PCC data (S4671) and writes PCC codec identification information in a predetermined position (e.g., a parameter set) in the encoded data (S4672). Next, the encoding unit 4613 generates NAL units including the encoded data and transmits the generated NAL units (S4673).

[0182] Furthermore, identification information of the PCC codec may be defined as a profile, and the identification information of the PCC codec may be indicated in metadata. Furthermore, when the same codec is used for the entire sequence, the sequence parameter set may include identification information of the PCC codec. Furthermore, when each PCC frame is encoded with a different codec, the parameter set describing information for each frame may include identification information of the PCC codec. For example, when a different codec is used for each PCC data, such as when different codecs are used for position information and attribute information, the parameter set describing information for each data may include identification information of the PCC codec. In other words, information indicating the codec of the position information may be included in control information (parameter set, etc.) for the position information, and information indicating the codec of the attribute information may be included in control information (parameter set, etc.) for the attribute information.

[0183] The codec identification information may be stored in any of the above locations, or may be stored in multiple locations. For example, the codec identification information may be stored both in the coded stream and in the NAL unit header. Furthermore, when the codec identification information is stored in multiple locations, the same information may be stored in the multiple locations, or different information may be stored in the multiple locations. The different information may be, for example, information indicating a GPCC or a VPCC and information indicating one of multiple codecs obtained by subdividing the GPCC or the VPCC.

[0184] When a parameter set is included in an NAL unit, the demultiplexing unit 4641 or 4661 included in the decoding unit 4624 can determine whether the data included in the payload of the NAL unit is data coded using the first coding method or the second coding method by analyzing the description in the parameter set. This allows the decoding unit 4624 to quickly filter out NAL units that are not necessary for decoding.

[0185] 38 is a flowchart of the decoding process by the decoding unit 4624 in this case. First, the decoding unit 4624 receives an NAL unit (S4675), and identifies predetermined data (e.g., the parameter set) in which PCC codec identification information is described using pcc_nal_unit_type included in the NAL unit header (S4676). Next, the decoding unit 4624 analyzes the predetermined data (e.g., the parameter set) to identify the PCC codec indicated in the predetermined data (S4677). Next, the decoding unit 4624 decodes the coded data using the identified PCC codec (S4678).

[0186] Furthermore, in the above example, the coded stream is stored in an NAL unit, but a unit of a predetermined format may be used instead of the NAL unit.

[0187] (Fourth embodiment) In this embodiment, we will explain an encoding unit 4670 that has the functions of both the first encoding unit 4630 and the second encoding unit 4650 described above, and a decoding unit 4680 that has the functions of both the first decoding unit 4640 and the second decoding unit 4660.

[0188] 39 is a block diagram of an encoding unit 4670 according to this embodiment. This encoding unit 4670 includes the above-described first encoding unit 4630 and second encoding unit 4650, and a multiplexing unit 4671. The multiplexing unit 4671 multiplexes the encoded data generated by the first encoding unit 4630 and the encoded data generated by the second encoding unit 4650, and outputs the obtained encoded data.

[0189] 40 is a block diagram of a decoding unit 4680 according to this embodiment. This decoding unit 4680 includes the first decoding unit 4640 and second decoding unit 4660 described above, and a demultiplexing unit 4681. The demultiplexing unit 4681 extracts, from the input coded data, coded data coded using the first coding method and coded data coded using the second coding method. The demultiplexing unit 4681 outputs the coded data coded using the first coding method to the first decoding unit 4640, and outputs the coded data coded using the second coding method to the second decoding unit 4660.

[0190] With the above configuration, the encoding unit 4670 can encode point cloud data by selectively using the first encoding method or the second encoding method. Furthermore, the decoding unit 4680 can decode encoded data encoded using the first encoding method, encoded data encoded using the second encoding method, and encoded data encoded using both the first encoding method and the second encoding method.

[0191] For example, the encoding unit 4670 may switch the encoding method (the first encoding method and the second encoding method) in units of point cloud data or in units of frames. Furthermore, the encoding unit 4670 may switch the encoding method in units that can be encoded.

[0192] The encoding unit 4670 generates encoded data (encoded stream) including identification information of the PCC codec, as described in the first or third embodiment above, for example.

[0193] The demultiplexing unit 4681 included in the decoding unit 4680 identifies the data using, for example, the PCC codec identification information described in embodiment 1 or embodiment 3. If the data is data coded using a first coding method, the demultiplexing unit 4681 outputs the data to the first decoding unit 4640, and if the data is data coded using a second coding method, the demultiplexing unit 4681 outputs the data to the second decoding unit 4660.

[0194] In addition to the PCC codec identification information, the encoding unit 4670 may also send, as control information, information indicating whether both encoding methods or one of the encoding methods was used.

[0195] Next, the encoding process according to this embodiment will be described. Fig. 41 is a flowchart of the encoding process according to this embodiment. By using the PCC codec identification information described in Embodiments 1, 2, and 3, and the modifications, encoding processes compatible with multiple codecs become possible. Note that Fig. 41 shows an example in which the technique of Embodiment 1 is used, but similar processes can also be applied to other techniques.

[0196] First, the encoding unit 4670 encodes the PCC data using either one or both of the codecs of the first encoding method and the second encoding method (S4681).

[0197] If the codec used is the second encoding method (second encoding method in S4682), the encoding unit 4670 sets pcc_codec_type included in the NAL unit header to a value indicating that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4683). Next, the encoding unit 4670 sets pcc_nal_unit_type in the NAL unit header to an identifier of the NAL unit for the second encoding method (S4684). Then, the encoding unit 4670 generates an NAL unit that has the set NAL unit header and includes encoded data in its payload. Then, the encoding unit 4670 transmits the generated NAL unit (S4685).

[0198] On the other hand, if the codec used is the first encoding method (first encoding method in S4682), the encoding unit 4670 sets pcc_codec_type included in the NAL unit header to a value indicating that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4686). Next, the encoding unit 4670 sets pcc_nal_unit_type included in the NAL unit header to an identifier of the NAL unit for the first encoding method (S4687). Next, the encoding unit 4670 generates a NAL unit that has the set NAL unit header and includes encoded data in its payload. Then, the encoding unit 4670 transmits the generated NAL unit (S4685).

[0199] Next, the decoding process according to this embodiment will be described. Fig. 42 is a flowchart of the decoding process according to this embodiment. By using the PCC codec identification information described in the first, second, and third embodiments and the modifications, decoding processes compatible with a plurality of codecs become possible. Note that Fig. 42 shows an example in which the technique of the first embodiment is used, but similar processes can also be applied to other techniques.

[0200] First, the decoding unit 4680 receives an NAL unit (S4691). For example, this NAL unit is generated by the processing in the encoding unit 4670 described above.

[0201] Next, the decoding unit 4680 determines whether the pcc_codec_type included in the NAL unit header indicates the first encoding method or the second encoding method (S4692).

[0202] If pcc_codec_type indicates the second encoding method (second encoding method in S4692), the decoding unit 4680 determines that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4693).The second decoding unit 4660 then identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the second encoding method (S4694).The decoding unit 4680 then decodes the PCC data using the decoding process for the second encoding method (S4695).

[0203] On the other hand, if pcc_codec_type indicates the first encoding method (first encoding method in S4692), the decoding unit 4680 determines that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4696).The decoding unit 4680 then identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the first encoding method (S4697).The decoding unit 4680 then decodes the PCC data using the decoding process for the first encoding method (S4698).

[0204] As described above, a three-dimensional data encoding device according to one embodiment of the present disclosure generates an encoded stream by encoding three-dimensional data (e.g., point cloud data) (e.g., S4671 in FIG. 37), and stores information indicating the encoding method used for the encoding, either the first encoding method or the second encoding method (e.g., codec identification information), in the control information (e.g., parameter set) of the encoded stream (e.g., S4672 in FIG. 37).

[0205] According to this, when decoding an encoded stream generated by the three-dimensional data encoding device, the three-dimensional data decoding device can determine the encoding method used for encoding using the information stored in the control information, and therefore the three-dimensional data decoding device can correctly decode the encoded stream even when multiple encoding methods are used.

[0206] For example, the three-dimensional data includes position information. In the encoding step, the three-dimensional data encoding device encodes the position information. In the storing step, the three-dimensional data encoding device stores, in control information for the position information, information indicating which of the first encoding method and the second encoding method was used to encode the position information.

[0207] For example, the three-dimensional data includes position information and attribute information. In the encoding step, the three-dimensional data encoding device encodes the position information and the attribute information. In the storing step, the three-dimensional data encoding device stores, in control information for the position information, information indicating which of the first encoding method and the second encoding method was used to encode the position information, and stores, in control information for the attribute information, information indicating which of the first encoding method and the second encoding method was used to encode the attribute information.

[0208] This allows different encoding methods to be used for the position information and the attribute information, thereby improving encoding efficiency.

[0209] For example, the three-dimensional data encoding method further stores the encoded stream in one or more units (for example, NAL units) (for example, S4673 in FIG. 37).

[0210] For example, as described in Figures 15 to 18 of embodiment 1, the unit has a format common to the first encoding method and the second encoding method, and includes information indicating the type of data contained in the unit (e.g., pcc_nal_unit_type), which has independent definitions in the first encoding method and the second encoding method.

[0211] For example, as described in Figures 23 to 28 of embodiment 2, the unit has a format that is independent between the first encoding method and the second encoding method, and includes information indicating the type of data included in the unit, which has a definition that is independent between the first encoding method and the second encoding method (e.g., codec1_nal_unit_type or codec2_nal_unit_type).

[0212] For example, as described in Figures 32 to 34 of embodiment 3, the unit has a format common to the first encoding method and the second encoding method, and includes information indicating the type of data contained in the unit, and information (e.g., pcc_nal_unit_type) having a definition common to the first encoding method and the second encoding method.

[0213] For example, the three-dimensional data encoding device includes a processor and a memory, and the processor performs the above-mentioned processing using the memory.

[0214] Furthermore, the three-dimensional data decoding device according to this embodiment determines the encoding method used to encode the encoded stream (e.g., S4677 in FIG. 38) based on information indicating which of the first and second encoding methods was used to encode the three-dimensional data (e.g., codec identification information), which is included in control information (e.g., a parameter set) of the encoded stream generated by encoding the three-dimensional data, and decodes the encoded stream using the determined encoding method (e.g., S4678 in FIG. 38).

[0215] According to this, when decoding an encoded stream, the three-dimensional data decoding device can determine the encoding method used for encoding using the information stored in the control information, and therefore the three-dimensional data decoding device can correctly decode the encoded stream even when multiple encoding methods are used.

[0216] For example, the three-dimensional data includes position information, and the encoded stream includes encoded data of the position information. In the determination, the three-dimensional data decoding device determines the encoding method used to encode the position information based on information indicating which of the first encoding method and the second encoding method was used to encode the position information, the information being included in control information of the position information included in the encoded stream. In the decoding, the three-dimensional data decoding device decodes the encoded data of the position information using the determined encoding method used to encode the position information.

[0217] For example, the three-dimensional data includes position information and attribute information, and the encoded stream includes encoded data of the position information and encoded data of the attribute information. In the determination, the three-dimensional data decoding device determines the encoding method used to encode the position information based on information, which of the first encoding method and the second encoding method was used to encode the position information, included in control information of the position information included in the encoded stream, and determines the encoding method used to encode the attribute information based on information, which of the first encoding method and the second encoding method was used to encode the attribute information, included in control information of the attribute information included in the encoded stream. In the decoding, the three-dimensional data decoding device decodes the encoded data of the position information using the determined encoding method used to encode the position information, and decodes the encoded data of the attribute information using the determined encoding method used to encode the attribute information.

[0218] This allows different encoding methods to be used for the position information and the attribute information, thereby improving encoding efficiency.

[0219] For example, the coded stream is stored in one or more units (for example, NAL units), and the three-dimensional data decoding device further obtains the coded stream from the one or more units.

[0220] For example, as described in Figures 15 to 18 of embodiment 1, the unit has a format common to the first encoding method and the second encoding method, and includes information indicating the type of data contained in the unit (e.g., pcc_nal_unit_type), which has independent definitions in the first encoding method and the second encoding method.

[0221] For example, as described in Figures 23 to 28 of embodiment 2, the unit has a format that is independent between the first encoding method and the second encoding method, and includes information indicating the type of data included in the unit, which has a definition that is independent between the first encoding method and the second encoding method (e.g., codec1_nal_unit_type or codec2_nal_unit_type).

[0222] For example, as described in Figures 32 to 34 of embodiment 3, the unit has a format common to the first encoding method and the second encoding method, and includes information indicating the type of data contained in the unit, and information (e.g., pcc_nal_unit_type) having a definition common to the first encoding method and the second encoding method.

[0223] For example, the three-dimensional data decoding device includes a processor and a memory, and the processor performs the above processing using the memory.

[0224] (Embodiment 5) In this embodiment, a method for storing the NAL units described in the first embodiment in an ISOBMFF file will be described.

[0225] ISOBMFF (ISO based media file format) is a file format standard defined in ISO / IEC 14496-12. ISOBMFF is a media-independent standard that defines a format that can store multiplexed media such as video, audio, and text.

[0226] This section explains the basic structure (file) of ISOBMFF. The basic unit in ISOBMFF is a box. A box consists of type, length, and data, and a file is a collection of boxes of various types.

[0227] 43 is a diagram showing the basic structure (file) of ISOBMFF. An ISOBMFF file mainly includes boxes such as ftyp, which indicates the file brand using 4CC (four-character code), moov, which stores metadata such as control information, and mdat, which stores data.

[0228] Storing methods for each media type in ISOBMFF files are specified separately. For example, storage methods for AVC video and HEVC video are specified in ISO / IEC 14496-15. While it is conceivable to extend and use the functions of ISOBMFF to store or transmit PCC encoded data, there are no regulations yet for storing PCC encoded data in ISOBMFF files. Therefore, in this embodiment, a method for storing PCC encoded data in an ISOBMFF file will be described.

[0229] 44 is a diagram showing a protocol stack when NAL units common to PCC codecs are stored in an ISOBMFF file. Here, the NAL units common to PCC codecs described in the first embodiment are stored in an ISOBMFF file. Although the NAL units are common to PCC codecs, multiple PCC codecs are stored in the NAL units, so it is desirable to define a storage method (Carriage of Codec1, Carriage of Codec2) according to each codec.

[0230] Next, a method for storing a common PCC NAL unit that supports multiple PCC codecs in an ISOBMFF file will be described. Fig. 45 is a diagram showing an example of storing a common PCC NAL unit in an ISOBMFF file using the storage method for codec 1 (Carriage of Codec1). Fig. 46 is a diagram showing an example of storing a common PCC NAL unit in an ISOBMFF file using the storage method for codec 2 (Carriage of Codec2).

[0231] Here, ftyp is important information for identifying the file format, and a different identifier is defined for ftyp for each codec. When PCC-encoded data encoded using a first encoding method (encoding system) is stored in a file, ftyp=pcc1 is set. When PCC-encoded data encoded using a second encoding method is stored in a file, ftyp=pcc2 is set.

[0232] Here, pcc1 indicates that PCC codec 1 (first encoding method) is used, and pcc2 indicates that PCC codec 2 (second encoding method) is used. In other words, pcc1 and pcc2 indicate that the data is PCC (coded data of three-dimensional data (point cloud data)), and also indicate the PCC codecs (first and second encoding methods).

[0233] A method for storing NAL units in an ISOBMFF file will be described below. The multiplexing unit analyzes the NAL unit header, and if pcc_codec_type=Codec1, writes pcc1 in ftyp of ISOBMFF.

[0234] Furthermore, the multiplexing unit analyzes the NAL unit header, and if pcc_codec_type=Codec2, writes pcc2 in ftyp of ISOBMFF.

[0235] Furthermore, if pcc_nal_unit_type is metadata, the multiplexing unit stores the NAL unit in a predetermined manner, for example, in moov or mdat. If pcc_nal_unit_type is data, the multiplexing unit stores the NAL unit in a predetermined manner, for example, in moov or mdat.

[0236] For example, the multiplexing unit may store the NAL unit size in the NAL unit, similar to HEVC.

[0237] This storage method enables the demultiplexer (system layer) to analyze the ftyp included in the file to determine whether the PCC-encoded data was encoded using the first encoding method or the second encoding method. Furthermore, as described above, by determining whether the PCC-encoded data was encoded using the first encoding method or the second encoding method, it is possible to extract encoded data encoded using one of the encoding methods from data containing a mixture of data encoded using both encoding methods. This reduces the amount of data transmitted when transmitting encoded data. Furthermore, this storage method allows a common data format to be used for the first encoding method and the second encoding method, without requiring different data (file) formats to be set.

[0238] In addition, when codec identification information is indicated in metadata of the system layer, such as ftyp in ISOBMFF, the multiplexing unit may store NAL units from which pcc_nal_unit_type has been deleted in an ISOBMFF file.

[0239] Next, the configuration and operation of the multiplexing unit provided in the three-dimensional data encoding system (three-dimensional data encoding device) according to this embodiment and the demultiplexing unit provided in the three-dimensional data decoding system (three-dimensional data decoding device) according to this embodiment will be described.

[0240] 47 is a diagram showing the configuration of the first multiplexing unit 4710. The first multiplexing unit 4710 includes a file conversion unit 4711 that generates multiplexed data (file) by storing the coded data and control information (NAL units) generated by the first coding unit 4630 in an ISOBMFF file. This first multiplexing unit 4710 is included in, for example, the multiplexing unit 4614 shown in FIG. 1.

[0241] 48 is a diagram showing the configuration of the first demultiplexing unit 4720. The first demultiplexing unit 4720 includes a file inverse conversion unit 4721 that acquires coded data and control information (NAL units) from multiplexed data (file) and outputs the acquired coded data and control information to the first decoding unit 4640. This first demultiplexing unit 4720 is included in the demultiplexing unit 4623 shown in FIG. 1, for example.

[0242] 49 is a diagram showing the configuration of the second multiplexing unit 4730. The second multiplexing unit 4730 includes a file conversion unit 4731 that generates multiplexed data (file) by storing the coded data and control information (NAL units) generated by the second coding unit 4650 in an ISOBMFF file. This second multiplexing unit 4730 is included in, for example, the multiplexing unit 4614 shown in FIG. 1.

[0243] 50 is a diagram showing the configuration of the second demultiplexing unit 4740. The second demultiplexing unit 4740 includes a file inverse conversion unit 4741 that acquires coded data and control information (NAL units) from multiplexed data (file) and outputs the acquired coded data and control information to the second decoding unit 4660. This second demultiplexing unit 4740 is included in, for example, the demultiplexing unit 4623 shown in FIG.

[0244] 51 is a flowchart of the multiplexing process by the first multiplexing unit 4710. First, the first multiplexing unit 4710 analyzes pcc_codec_type included in the NAL unit header to determine whether the codec being used is the first encoding method or the second encoding method (S4701).

[0245] If pcc_codec_type indicates the second encoding method (second encoding method in S4702), the first multiplexing unit 4710 does not process the NAL unit (S4703).

[0246] On the other hand, if pcc_codec_type indicates the second encoding method (first encoding method in S4702), the first multiplexing unit 4710 writes pcc1 in ftyp (S4704). In other words, the first multiplexing unit 4710 writes information in ftyp indicating that data encoded using the first encoding method is stored in the file.

[0247] Next, the first multiplexing unit 4710 analyzes the pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) using a predetermined method according to the data type indicated by the pcc_nal_unit_type (S4705).Then, the first multiplexing unit 4710 creates an ISOBMFF file including the ftyp and the box (S4706).

[0248] 52 is a flowchart of the multiplexing process by the second multiplexing unit 4730. First, the second multiplexing unit 4730 analyzes pcc_codec_type included in the NAL unit header to determine whether the codec being used is the first encoding method or the second encoding method (S4711).

[0249] If pcc_unit_type indicates the second encoding method (second encoding method in S4712), the second multiplexing unit 4730 writes pcc2 in ftyp (S4713). In other words, the second multiplexing unit 4730 writes information in ftyp indicating that data encoded using the second encoding method is stored in the file.

[0250] Next, the second multiplexing unit 4730 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, etc.) using a predetermined method according to the data type indicated by pcc_nal_unit_type (S4714).Then, the second multiplexing unit 4730 creates an ISOBMFF file including the ftyp and the box (S4715).

[0251] On the other hand, if pcc_unit_type indicates the first encoding method (first encoding method in S4712), the second multiplexing unit 4730 does not process the NAL unit (S4716).

[0252] Note that the above process shows an example in which PCC data is encoded using either the first encoding method or the second encoding method. The first multiplexing unit 4710 and the second multiplexing unit 4730 store the desired NAL unit in a file by identifying the codec type of the NAL unit. Note that if PCC codec identification information is included in addition to the NAL unit header, the first multiplexing unit 4710 and the second multiplexing unit 4730 may identify the codec type (first encoding method or second encoding method) in steps S4701 and S4711 using the PCC codec identification information included in addition to the NAL unit header.

[0253] Furthermore, when storing data in a file in steps S4706 and S4714, the first multiplexing unit 4710 and the second multiplexing unit 4730 may delete pcc_nal_unit_type from the NAL unit header before storing the data in the file.

[0254] 53 is a flowchart showing the processing by the first demultiplexing unit 4720 and the first decoding unit 4640. First, the first demultiplexing unit 4720 analyzes ftyp included in the ISOBMFF file (S4721). If the codec indicated by ftyp is the second encoding method (pcc2) (second encoding method in S4722), the first demultiplexing unit 4720 determines that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4723). The first demultiplexing unit 4720 also conveys the result of this determination to the first decoding unit 4640. The first decoding unit 4640 does not process the NAL unit (S4724).

[0255] On the other hand, if the codec indicated by ftyp is the first encoding method (pcc1) (first encoding method in S4722), the first demultiplexing unit 4720 determines that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4725). In addition, the first demultiplexing unit 4720 conveys the result of this determination to the first decoding unit 4640.

[0256] The first decoding unit 4640 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the first encoding method (S4726).Then, the first decoding unit 4640 decodes the PCC data using the decoding process for the first encoding method (S4727).

[0257] 54 is a flowchart showing the processing by the second demultiplexing unit 4740 and the second decoding unit 4660. First, the second demultiplexing unit 4740 analyzes ftyp included in the ISOBMFF file (S4731). If the codec indicated by ftyp is the second encoding method (pcc2) (second encoding method in S4732), the second demultiplexing unit 4740 determines that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4733). The second demultiplexing unit 4740 also conveys the result of this determination to the second decoding unit 4660.

[0258] The second decoding unit 4660 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the second encoding method (S4734).Then, the second decoding unit 4660 decodes the PCC data using the decoding process for the second encoding method (S4735).

[0259] On the other hand, if the codec indicated by ftyp is the first encoding method (pcc1) (first encoding method in S4732), the second demultiplexing unit 4740 determines that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4736). The second demultiplexing unit 4740 also conveys the result of this determination to the second decoding unit 4660. The second decoding unit 4660 does not process the NAL unit (S4737).

[0260] In this way, for example, by identifying the codec type of the NAL unit in the first demultiplexing unit 4720 or the second demultiplexing unit 4740, the codec type can be identified at an early stage. Furthermore, desired NAL units can be input to the first decoding unit 4640 or the second decoding unit 4660, and unnecessary NAL units can be removed. In this case, the process of analyzing codec identification information may become unnecessary in the first decoding unit 4640 or the second decoding unit 4660. Note that the first decoding unit 4640 or the second decoding unit 4660 may again refer to the NAL unit type and perform the process of analyzing codec identification information.

[0261] In addition, if the first multiplexing unit 4710 or the second multiplexing unit 4730 removes the pcc_nal_unit_type from the NAL unit header, the first demultiplexing unit 4720 or the second demultiplexing unit 4740 may add the pcc_nal_unit_type to the NAL unit and then output it to the first decoding unit 4640 or the second decoding unit 4660.

[0262] (Embodiment 6) This embodiment will describe a multiplexing unit and a demultiplexing unit corresponding to the encoding unit 4670 and decoding unit 4680 that support multiple codecs, as described in Embodiment 4. Figure 55 shows the configurations of the encoding unit 4670 and third multiplexing unit 4750 according to this embodiment.

[0263] The encoding unit 4670 encodes the point cloud data using either or both of a first encoding method and a second encoding method. The encoding unit 4670 may switch the encoding method (the first encoding method and the second encoding method) for each point cloud data unit or for each frame unit. The encoding unit 4670 may also switch the encoding method for each encoding unit.

[0264] The encoding unit 4670 generates encoded data (encoded stream) including identification information of the PCC codec, as described in the first to fourth embodiments.

[0265] The third multiplexing unit 4750 includes a file conversion unit 4751. The file conversion unit 4751 converts the NAL units output from the encoding unit 4670 into a PCC data file. The file conversion unit 4751 analyzes the codec identification information included in the NAL unit header and determines whether the PCC-encoded data is data encoded using a first encoding method, data encoded using a second encoding method, or data encoded using both methods. The file conversion unit 4751 writes a brand name that can identify the codec in ftyp. For example, to indicate that the data has been encoded using both methods, pcc3 is written in ftyp.

[0266] If the encoding unit 4670 describes PCC codec identification information outside the NAL unit, the file conversion unit 4751 may use this identification information to determine the PCC codec (encoding method).

[0267] FIG. 56 shows the configuration of the third demultiplexing unit 4760 and the decoding unit 4680 according to this embodiment.

[0268] The third demultiplexing unit 4760 includes a file inverse conversion unit 4761. The file inverse conversion unit 4761 analyzes the ftyp included in the file and determines whether the PCC encoded data is data encoded using the first encoding method, data encoded using the second encoding method, or data encoded using both methods.

[0269] When the PCC-encoded data is encoded using one of the encoding methods, the data is input to the corresponding decoding unit out of the first decoding unit 4640 and the second decoding unit 4660, and the data is not input to the other decoding unit. When the PCC-encoded data is encoded using both encoding methods, the data is input to a decoding unit 4680 that supports both methods.

[0270] The decoding unit 4680 decodes the PCC encoded data using either or both of the first encoding method and the second encoding method.

[0271] FIG. 57 is a flowchart showing processing by the third multiplexing unit 4750 according to this embodiment.

[0272] First, the third multiplexing unit 4750 analyzes the pcc_codec_type included in the NAL unit header to determine whether the codec being used is the first encoding method, the second encoding method, or both the first and second encoding methods (S4741).

[0273] If the second encoding method is used (Yes in S4742 and the second encoding method in S4743), the third multiplexing unit 4750 writes pcc2 in ftyp (S4744). That is, the third multiplexing unit 4750 writes information indicating that data encoded using the second encoding method is stored in the file in ftyp.

[0274] Next, the third multiplexing unit 4750 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, etc.) using a predetermined method according to the data type indicated by pcc_unit_type (S4745).Then, the third multiplexing unit 4750 creates an ISOBMFF file including the ftyp and the box (S4746).

[0275] On the other hand, if the first encoding method is used (Yes in S4742 and the first encoding method in S4743), the third multiplexing unit 4750 writes pcc1 in ftyp (S4747). That is, the third multiplexing unit 4750 writes information indicating that data encoded using the first encoding method is stored in the file in ftyp.

[0276] Next, the third multiplexing unit 4750 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) using a predetermined method according to the data type indicated by pcc_unit_type (S4748).Then, the third multiplexing unit 4750 creates an ISOBMFF file including the ftyp and the box (S4746).

[0277] On the other hand, if both the first encoding method and the second encoding method are used (No in S4742), the third multiplexing unit 4750 writes pcc3 in ftyp (S4749). That is, the third multiplexing unit 4750 writes information in ftyp indicating that data encoded using both encoding methods is stored in the file.

[0278] Next, the third multiplexing unit 4750 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, etc.) using a predetermined method according to the data type indicated by pcc_unit_type (S4750).Then, the third multiplexing unit 4750 creates an ISOBMFF file including the ftyp and the box (S4746).

[0279] 58 is a flowchart showing the processing by the third demultiplexing unit 4760 and the decoding unit 4680. First, the third demultiplexing unit 4760 analyzes ftyp included in the ISOBMFF file (S4761). If the codec indicated by ftyp is the second encoding method (pcc2) (Yes in S4762 and the second encoding method in S4763), the third demultiplexing unit 4760 determines that the data included in the payload of the NAL unit is data encoded using the second encoding method (S4764). Furthermore, the third demultiplexing unit 4760 conveys the result of this determination to the decoding unit 4680.

[0280] The decoding unit 4680 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the second encoding method (S4765).The decoding unit 4680 then decodes the PCC data using the decoding process for the second encoding method (S4766).

[0281] On the other hand, if the codec indicated by ftyp is the first encoding method (pcc1) (Yes in S4762 and the first encoding method in S4763), the third demultiplexing unit 4760 determines that the data included in the payload of the NAL unit is data encoded using the first encoding method (S4767). The third demultiplexing unit 4760 also conveys the result of this determination to the decoding unit 4680.

[0282] The decoding unit 4680 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the first encoding method (S4768).The decoding unit 4680 then decodes the PCC data using the decoding process for the first encoding method (S4769).

[0283] On the other hand, if ftyp indicates that both encoding methods are used (pcc3) (No in S4762), the third demultiplexing unit 4760 determines that the data included in the payload of the NAL unit is data encoded using both the first encoding method and the second encoding method (S4770). The third demultiplexing unit 4760 also conveys the result of this determination to the decoding unit 4680.

[0284] The decoding unit 4680 identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the codec described in pcc_codec_type (S4771). Then, the decoding unit 4680 decodes the PCC data using the decoding processes of both encoding methods (S4772). That is, the decoding unit 4680 decodes data encoded using the first encoding method using the decoding process of the first encoding method, and decodes data encoded using the second encoding method using the decoding process of the second encoding method.

[0285] Modifications of this embodiment will be described below. As the brand type indicated in ftyp, the following types may be indicated by the identification information. Also, a combination of the following types may be indicated by the identification information.

[0286] The identification information may indicate whether the object in the original data before PCC encoding is a point cloud with a restricted area or a large-scale point cloud with an unrestricted area such as map information.

[0287] The identification information may indicate whether the original data before PCC encoding is a static object or a dynamic object.

[0288] As described above, the identification information may indicate whether the PCC encoded data is data encoded using a first encoding method or data encoded using a second encoding method.

[0289] The identification information may indicate the algorithm used in the PCC encoding, where the algorithm is, for example, an encoding method that can be used in the first encoding method or the second encoding method.

[0290] The identification information may indicate differences in the storage method of PCC-encoded data in an ISOBMFF file. For example, the identification information may indicate whether the storage method used is for storage or for real-time transmission such as dynamic streaming.

[0291] In addition, in embodiment 5, the method of storing NAL units described in embodiment 1 is described, and in embodiment 6, the method of storing NAL units described in embodiment 4 is described. However, by applying the same storage method to the NAL units described in embodiments 2 and 3, the identification information of the PCC codec may be stored in the ISOBMFF file.

[0292] Although the fifth and sixth embodiments have been described with reference to examples in which ISOBMFF is used as the file format, other formats may also be used. For example, a method similar to that of the present embodiment may also be used when storing PCC encoded data in MPEG-2 TS Systems, MPEG-DASH, MMT, or RMP.

[0293] Although the above example shows that metadata such as identification information is stored in ftyp, this metadata may be stored in a location other than ftyp. For example, this metadata may be stored in moov.

[0294] As described above, the three-dimensional data storage device (or the three-dimensional data multiplexing device, or the three-dimensional data encoding device) performs the processing shown in FIG.

[0295] First, the three-dimensional data storage device (including, for example, the first multiplexing unit 4710, the second multiplexing unit 4730, or the third multiplexing unit 4750) acquires one or more units (for example, NAL units) in which an encoded stream in which point cloud data has been encoded is stored (S4781). Next, the three-dimensional data storage device stores the one or more units in a file (for example, an ISOBMFF file) (S4782). Furthermore, in the storing step (S4782), the three-dimensional data storage device stores information (for example, pcc1, pcc2, or pcc3) indicating that the data stored in the file is data in which point cloud data has been encoded, in the control information (for example, ftyp) of the file.

[0296] This allows a device that processes a file generated by the three-dimensional data storage device to refer to the control information of the file and quickly determine whether the data stored in the file is encoded point cloud data, thereby reducing the processing load of the device and speeding up processing.

[0297] For example, the information further indicates which of the first and second encoding methods was used to encode the point cloud data. Note that the fact that the data stored in the file is encoded point cloud data and the encoding method of the first and second encoding methods used to encode the point cloud data may be indicated by a single piece of information or by different pieces of information.

[0298] This allows a device that processes a file created by the three-dimensional data storage device to quickly determine the codec used for the data stored in the file by referencing the file's control information, thereby reducing the processing load of the device or speeding up processing.

[0299] For example, the first encoding method is a method (GPCC) in which position information representing the positions of point cloud data as an N-ary tree (N is an integer greater than or equal to 2) and attribute information is encoded using the position information, and the second encoding method is a method (VPCC) in which a two-dimensional image is generated from the point cloud data and the two-dimensional image is encoded using a video encoding method.

[0300] For example, the file conforms to ISOBMFF (ISO based media file format).

[0301] For example, the three-dimensional data storage device includes a processor and a memory, and the processor uses the memory to perform the above processing.

[0302] As described above, the three-dimensional data acquisition device (or the three-dimensional data demultiplexing device, or the three-dimensional data decoding device) performs the processing shown in FIG.

[0303] The three-dimensional data acquisition device (including, for example, the first demultiplexing unit 4720, the second demultiplexing unit 4740, or the third demultiplexing unit 4760) acquires a file (for example, an ISOBMFF file) that stores one or more units (for example, NAL units) in which an encoded stream in which point cloud data is encoded is stored (S4791). Next, the three-dimensional data acquisition device acquires one or more units from the file (S4792). In addition, the control information of the file (for example, ftyp) includes information (for example, pcc1, pcc2, or pcc3) that indicates that the data stored in the file is data in which point cloud data is encoded.

[0304] For example, the three-dimensional data acquisition device refers to the information and determines whether the data stored in the file is encoded point cloud data. Furthermore, if the three-dimensional data acquisition device determines that the data stored in the file is encoded point cloud data, it generates point cloud data by decoding the encoded point cloud data included in one or more units. Alternatively, if the three-dimensional data acquisition device determines that the data stored in the file is encoded point cloud data, it outputs (notifies) information indicating that the data included in one or more units is encoded point cloud data to a downstream processing unit (e.g., the first decoding unit 4640, the second decoding unit 4660, or the decoding unit 4680).

[0305] This allows the 3D data acquisition device to refer to the control information of the file and quickly determine whether the data stored in the file is encoded point cloud data, thereby reducing the processing load of the 3D data acquisition device or a downstream device and increasing the processing speed.

[0306] For example, the information further indicates the encoding method used for the encoding, either the first encoding method or the second encoding method. Note that the fact that the data stored in the file is data obtained by encoding point cloud data and the encoding method used for encoding the point cloud data, either the first encoding method or the second encoding method, may be indicated by a single piece of information or by different pieces of information.

[0307] This allows the 3D data acquisition device to refer to the control information of the file and quickly determine the codec used for the data stored in the file, thereby reducing the processing load of the 3D data acquisition device or a downstream device and increasing the processing speed.

[0308] For example, based on the information, the three-dimensional data acquisition device acquires data encoded using one of the encoding methods from encoded point cloud data that includes data encoded using the first encoding method and data encoded using the second encoding method.

[0309] For example, the first encoding method is a method (GPCC) in which position information representing the positions of point cloud data as an N-ary tree (N is an integer greater than or equal to 2) and attribute information is encoded using the position information, and the second encoding method is a method (VPCC) in which a two-dimensional image is generated from the point cloud data and the two-dimensional image is encoded using a video encoding method.

[0310] For example, the file conforms to ISOBMFF (ISO based media file format).

[0311] For example, the three-dimensional data acquisition device includes a processor and a memory, and the processor performs the above-mentioned processing using the memory.

[0312] (Embodiment 7) In this embodiment, the types of coded data (position information (Geometry), attribute information (Attribute), additional information (Metadata)) generated by the first coding unit 4630 or the second coding unit 4650 described above, a method for generating the additional information (Metadata), and multiplexing processing in the multiplexing unit will be described. Note that the additional information (Metadata) may also be referred to as a parameter set or control information.

[0313] In this embodiment, the dynamic object (three-dimensional point cloud data that changes over time) described in Figure 4 will be used as an example, but a similar method may also be used in the case of a static object (three-dimensional point cloud data at any time).

[0314] 61 is a diagram showing the configurations of an encoding unit 4801 and a multiplexing unit 4802 included in a three-dimensional data encoding device according to this embodiment. The encoding unit 4801 corresponds to, for example, the first encoding unit 4630 or the second encoding unit 4650 described above. The multiplexing unit 4802 corresponds to the multiplexing unit 4634 or 46456 described above.

[0315] The encoding unit 4801 encodes point cloud data of multiple PCC (Point Cloud Compression) frames, and generates encoded data (Multiple Compressed Data) of multiple pieces of position information, attribute information, and additional information.

[0316] The multiplexing unit 4802 converts data of multiple data types (position information, attribute information, and additional information) into NAL units, thereby converting the data into a data structure that takes into account data access in the decoding device.

[0317] 62 is a diagram showing an example of the structure of coded data generated by the coding unit 4801. The arrows in the diagram indicate dependencies related to the decoding of coded data, with the source of the arrow depending on the data at the end of the arrow. In other words, the decoding device decodes the data at the end of the arrow and uses the decoded data to decode the data at the end of the arrow. In other words, dependency means that the data on which the dependency is based is referenced (used) in the processing (encoding, decoding, etc.) of the data on which the dependency is based.

[0318] First, the process of generating encoded data of position information will be described. The encoding unit 4801 generates encoded position data (compressed geometry data) for each frame by encoding the position information of each frame. The encoded position data is represented by G(i), where i indicates the frame number, the time of the frame, etc.

[0319] The encoding unit 4801 also generates a position parameter set (GPS(i)) corresponding to each frame. The position parameter set includes parameters that can be used to decode the encoded position data. The encoded position data for each frame depends on the corresponding position parameter set.

[0320] Furthermore, encoded position data consisting of multiple frames is defined as a position sequence (Geometry Sequence). The encoding unit 4801 generates a position sequence parameter set (Geometry Sequence PS: also referred to as position SPS) that stores parameters commonly used in decoding processes for multiple frames in the position sequence. The position sequence depends on the position SPS.

[0321] Next, the process of generating coded data of attribute information will be described. The coding unit 4801 generates coded attribute data (Compressed Attribute Data) for each frame by coding the attribute information of each frame. The coded attribute data is represented by A(i). Also, Fig. 62 shows an example in which attribute X and attribute Y exist, and the coded attribute data of attribute X is represented by AX(i) and the coded attribute data of attribute Y is represented by AY(i).

[0322] The encoding unit 4801 also generates an attribute parameter set (APS(i)) corresponding to each frame. The attribute parameter set for attribute X is represented as AXPS(i), and the attribute parameter set for attribute Y is represented as AYPS(i). The attribute parameter set includes parameters that can be used to decode encoded attribute information. The encoded attribute data depends on the corresponding attribute parameter set.

[0323] Furthermore, encoded attribute data consisting of multiple frames is defined as an attribute sequence. The encoding unit 4801 generates an attribute sequence parameter set (Attribute Sequence PS: also referred to as attribute SPS) that stores parameters commonly used in decoding processes for multiple frames in the attribute sequence. The attribute sequence depends on the attribute SPS.

[0324] Furthermore, in the first encoding method, the encoded attribute data depends on the encoded position data.

[0325] Also, Figure 62 shows an example where two types of attribute information (attribute X and attribute Y) exist. When there are two types of attribute information, for example, two encoding units generate respective data and metadata. Also, for example, an attribute sequence is defined for each type of attribute information, and an attribute SPS is generated for each type of attribute information.

[0326] Note that, while FIG. 62 shows an example in which there is one type of position information and two types of attribute information, the present invention is not limited to this, and there may be one type of attribute information, or three or more types. In this case, encoded data can be generated using a similar method. Furthermore, in the case of point cloud data that does not have attribute information, the attribute information may not be necessary. In this case, the encoding unit 4801 does not need to generate a parameter set related to the attribute information.

[0327] Next, the process of generating additional information (metadata) will be described. The encoding unit 4801 generates a PCC Stream PS (also referred to as stream PS), which is a parameter set for the entire PCC stream. The encoding unit 4801 stores, in the stream PS, parameters that can be used in common for decoding processes for one or more position sequences and one or more attribute sequences. For example, the stream PS includes identification information indicating the codec for the point cloud data, information indicating the algorithm used for encoding, and the like. The position sequence and attribute sequence depend on the stream PS.

[0328] Next, the access unit and GOF will be explained. In this embodiment, the concepts of the access unit (AU) and GOF (Group of Frame) are newly introduced.

[0329] An access unit is a basic unit for accessing data during decoding, and is composed of one or more pieces of data and one or more pieces of metadata. For example, an access unit is composed of position information at the same time and one or more pieces of attribute information. A GOF is a random access unit and is composed of one or more access units.

[0330] The encoding unit 4801 generates an access unit header (AU Header) as identification information indicating the beginning of an access unit. The encoding unit 4801 stores parameters related to the access unit in the access unit header. For example, the access unit header includes the configuration or information of the coded data included in the access unit. The access unit header also includes parameters commonly used for the data included in the access unit, such as parameters related to decoding of the coded data.

[0331] Instead of an access unit header, the encoding unit 4801 may generate an access unit delimiter that does not include parameters related to the access unit. This access unit delimiter is used as identification information indicating the start of the access unit. The decoding device identifies the start of the access unit by detecting the access unit header or the access unit delimiter.

[0332] Next, generation of identification information for the start of a GOF will be described. The encoding unit 4801 generates a GOF header as identification information indicating the start of a GOF. The encoding unit 4801 stores parameters related to the GOF in the GOF header. For example, the GOF header includes the configuration or information of the coded data included in the GOF. The GOF header also includes parameters commonly used for the data included in the GOF, such as parameters related to decoding of the coded data.

[0333] Instead of a GOF header, the encoding unit 4801 may generate a GOF delimiter that does not include parameters related to the GOF. This GOF delimiter is used as identification information that indicates the beginning of the GOF. The decoding device identifies the beginning of the GOF by detecting the GOF header or the GOF delimiter.

[0334] In PCC encoded data, for example, an access unit is defined as a PCC frame unit, and a decoding device accesses a PCC frame based on identification information at the beginning of the access unit.

[0335] Also, for example, GOF is defined as one random access unit. A decoding device accesses the random access unit based on the identification information at the beginning of the GOF. For example, if PCC frames are not dependent on each other and can be decoded independently, the PCC frames may be defined as the random access unit.

[0336] It should be noted that two or more PCC frames may be allocated to one access unit, and multiple random access units may be allocated to one GOF.

[0337] The encoding unit 4801 may also define and generate parameter sets or metadata other than those described above. For example, the encoding unit 4801 may generate SEI (Supplemental Enhancement Information) that stores parameters (optional parameters) that may not necessarily be used during decoding.

[0338] Next, the structure of coded data and the method of storing coded data in NAL units will be described.

[0339] For example, a data format is defined for each type of coded data. Figure 63 shows examples of coded data and NAL units.

[0340] For example, as shown in Figure 63, the coded data includes a header and a payload. The coded data may include length information indicating the length (amount of data) of the coded data, header, or payload. The coded data may not necessarily include a header.

[0341] The header includes, for example, identification information for identifying the data, such as the data type or frame number.

[0342] The header includes, for example, identification information indicating a reference relationship. This identification information is stored in the header when, for example, there is a dependency relationship between data, and is information for referencing the reference destination from the reference source. For example, the header of the reference destination includes identification information for identifying the data. The header of the reference source includes identification information indicating the reference destination.

[0343] If the reference destination or the reference source can be identified or derived from other information, the identification information for specifying the data or the identification information indicating the reference relationship may be omitted.

[0344] The multiplexing unit 4802 stores the coded data in the payload of the NAL unit. The NAL unit header includes pcc_nal_unit_type, which is information identifying the coded data. Figure 64 shows an example of the semantics of pcc_nal_unit_type.

[0345] As shown in Figure 64, when pcc_codec_type is codec 1 (Codec1: first encoding method), values ​​0 to 10 of pcc_nal_unit_type are assigned to the encoded position data (Geometry), encoded attribute X data (AttributeX), encoded attribute Y data (AttributeY), position PS (Geom.PS), attribute XPS (AttrX.PS), attribute YPS (AttrX.PS), position SPS (Geometry Sequence PS), attribute XSPS (AttributeX Sequence PS), attribute YSPS (AttributeY Sequence PS), AU header (AU Header), and GOF header (GOF Header) in codec 1. Values ​​11 and above are assigned as spares for codec 1.

[0346] When pcc_codec_type is Codec2 (Codec2: second encoding method), values ​​0 to 2 of pcc_nal_unit_type are assigned to codec data A (DataA), metadata A (MetaDataA), and metadata B (MetaDataB). Values ​​3 and above are assigned as spares for Codec2.

[0347] Next, the data transmission order will be explained. The following explains the restrictions on the transmission order of NAL units.

[0348] The multiplexing unit 4802 collectively transmits NAL units in units of GOF or AU. The multiplexing unit 4802 places a GOF header at the beginning of a GOF, and places an AU header at the beginning of an AU.

[0349] The multiplexing unit 4802 may allocate a sequence parameter set (SPS) for each AU so that the decoding device can decode from the next AU even if data is lost due to packet loss or the like.

[0350] If the coded data has a dependency relationship related to decoding, the decoding device decodes the referenced data first, and then decodes the referenced data. In order to enable the decoding device to decode the data in the order in which it was received without rearranging the data, the multiplexing unit 4802 sends the referenced data first.

[0351] Figure 65 shows examples of the transmission order of NAL units, showing three examples: position information priority, parameter priority, and data integration.

[0352] The sending order with priority given to location information is an example in which information related to location information and information related to attribute information are sent together. In this sending order, the sending of information related to location information is completed earlier than the sending of information related to attribute information.

[0353] For example, by using this transmission order, a decoding device that does not decode attribute information may be able to set a time during which it does not process the attribute information by ignoring the decoding of the attribute information. Also, for example, in the case of a decoding device that wants to decode position information quickly, it may be able to decode the position information more quickly by obtaining the encoded data of the position information early.

[0354] In FIG. 65, the attributes XSPS and YSPS are combined and written as the attribute SPS, but the attributes XSPS and YSPS may be arranged separately.

[0355] In the parameter set priority sending order, the parameter sets are sent first and the data is sent later.

[0356] As long as the NAL unit transmission order constraints are met as described above, the multiplexing unit 4802 may transmit NAL units in any order. For example, order identification information may be defined, and the multiplexing unit 4802 may have the function of transmitting NAL units in multiple order patterns. For example, the NAL unit order identification information may be stored in the stream PS.

[0357] The three-dimensional data decoding device may perform decoding based on the order identification information. The three-dimensional data decoding device may instruct the three-dimensional data encoding device on a desired transmission order, and the three-dimensional data encoding device (multiplexing unit 4802) may control the transmission order in accordance with the instructed transmission order.

[0358] The multiplexing unit 4802 may generate coded data that merges multiple functions, as long as the data transmission order is within the constraints of the transmission order, such as the transmission order of the integrated data. For example, as shown in FIG. 65, the GOF header and the AU header may be merged, or the AXPS and the AYPS may be merged. In this case, an identifier indicating that the data has multiple functions is defined in pcc_nal_unit_type.

[0359] A modified example of this embodiment will be described below. PS has levels, such as a frame-level PS, a sequence-level PS, and a PCC sequence-level PS, and if the PCC sequence level is the higher level and the frame level is the lower level, the following method may be used to store parameters.

[0360] The default PS value is indicated in the higher PS. Also, if the value of the lower PS differs from the value of the higher PS, the PS value is indicated in the lower PS. Alternatively, the PS value is not written in the higher PS, but written in the lower PS. Alternatively, information on whether the PS value is to be written in the lower PS, the higher PS, or both is written in either the lower PS or the higher PS, or both. Alternatively, the lower PS may be merged with the higher PS. Alternatively, if the lower PS and the higher PS overlap, the multiplexing unit 4802 may omit sending one of them.

[0361] The encoding unit 4801 or the multiplexing unit 4802 may divide the data into slices or tiles and transmit the divided data. The divided data includes information for identifying the divided data, and parameters used to decode the divided data are included in the parameter set. In this case, an identifier indicating that the data stores data or parameters related to tiles or slices is defined in pcc_nal_unit_type.

[0362] The processing related to the order identification information will be explained below. Figure 66 is a flowchart of processing by the three-dimensional data encoding device (the encoding unit 4801 and the multiplexing unit 4802) related to the transmission order of NAL units.

[0363] First, the three-dimensional data encoding device determines the transmission order of NAL units (position information priority or parameter set priority) (S4801). For example, the three-dimensional data encoding device determines the transmission order based on a specification from a user or an external device (e.g., a three-dimensional data decoding device).

[0364] If the determined transmission order is positional information priority (positional information priority in S4802), the three-dimensional data encoding device sets the order identification information included in the stream PS to positional information priority (S4803). That is, in this case, the order identification information indicates that the NAL units are to be transmitted in an order that prioritizes positional information. The three-dimensional data encoding device then transmits the NAL units in positional information priority order (S4804).

[0365] On the other hand, if the determined transmission order is parameter set priority (parameter set priority in S4802), the three-dimensional data encoding device sets the order identification information included in the stream PS to parameter set priority (S4805). That is, in this case, the order identification information indicates that the NAL units will be transmitted in parameter set priority order. Then, the three-dimensional data encoding device transmits the NAL units in parameter set priority order (S4806).

[0366] 67 is a flowchart of processing by the 3D data decoding device related to the transmission order of NAL units. First, the 3D data decoding device analyzes the order identification information included in the stream PS (S4811).

[0367] If the transmission order indicated by the order identification information is position information priority (position information priority in S4812), the three-dimensional data decoding device decodes the NAL units assuming that the transmission order of the NAL units is position information priority (S4813).

[0368] On the other hand, if the transmission order indicated by the order identification information is parameter set priority (parameter set priority in S4812), the three-dimensional data decoding device decodes the NAL units assuming that the transmission order of the NAL units is parameter set priority (S4814).

[0369] For example, if the three-dimensional data decoding device does not decode attribute information, in step S4813, it may acquire NAL units related to position information without acquiring all NAL units, and decode the position information from the acquired NAL units.

[0370] Next, the processing related to the generation of AUs and GOFs will be described. Fig. 68 is a flowchart of processing by the 3D data encoding device (the multiplexing unit 4802) related to the generation of AUs and GOFs in multiplexing NAL units.

[0371] First, the three-dimensional data encoding device determines the type of encoded data (S4821). Specifically, the three-dimensional data encoding device determines whether the encoded data to be processed is the first data of an AU, the first data of a GOF, or other data.

[0372] If the coded data is data at the start of a GOF (GOF start in S4822), the three-dimensional data coding device places a GOF header and an AU header at the start of the coded data belonging to the GOF to generate a NAL unit (S4823).

[0373] If the coded data is data at the beginning of an AU (AU beginning in S4822), the three-dimensional data coding device places an AU header at the beginning of the coded data belonging to the AU and generates a NAL unit (S4824).

[0374] If the encoded data is not at the beginning of a GOF or an AU (other than the beginning of a GOF or an AU in S4822), the three-dimensional data encoding device places the encoded data after the AU header of the AU to which the encoded data belongs and generates a NAL unit (S4825).

[0375] Next, a process for accessing AUs and GOFs will be described. Fig. 69 is a flowchart of a process performed by a three-dimensional data decoding device for accessing AUs and GOFs during demultiplexing of NAL units.

[0376] First, the three-dimensional data decoding device determines the type of coded data included in the NAL unit by analyzing the nal_unit_type included in the NAL unit (S4831). Specifically, the three-dimensional data decoding device determines whether the coded data included in the NAL unit is data at the beginning of an AU, data at the beginning of a GOF, or other data.

[0377] If the encoded data contained in the NAL unit is the data at the start of the GOF (start of GOF in S4832), the three-dimensional data decoding device determines that the NAL unit is the start position of random access, accesses the NAL unit, and starts the decoding process (S4833).

[0378] On the other hand, if the coded data contained in the NAL unit is data at the beginning of an AU (AU beginning in S4832), the three-dimensional data decoding device determines that the NAL unit is the beginning of an AU, accesses the data contained in the NAL unit, and decodes the AU (S4834).

[0379] On the other hand, if the coded data included in the NAL unit is neither the start of a GOF nor the start of an AU (other than the start of a GOF or an AU in S4832), the three-dimensional data decoding device does not process the NAL unit.

[0380] As described above, the three-dimensional data encoding device performs the processing shown in Fig. 70. The three-dimensional data encoding device encodes time-series three-dimensional data (for example, point cloud data of a dynamic object). The three-dimensional data includes position information and attribute information for each time.

[0381] First, the three-dimensional data encoding device encodes position information (S4841). Next, the three-dimensional data encoding device encodes the attribute information to be processed by referring to position information at the same time as the attribute information to be processed (S4842). Here, as shown in Fig. 62, the position information at the same time and the attribute information form an access unit (AU). In other words, the three-dimensional data encoding device encodes the attribute information to be processed by referring to position information included in the same access unit as the attribute information to be processed.

[0382] This allows the three-dimensional data encoding device to easily control references during encoding using the access unit, thereby reducing the amount of processing required for encoding.

[0383] For example, a three-dimensional data encoding device generates a bitstream including encoded position information (encoded position data), encoded attribute information (encoded attribute data), and information indicating the position information referenced by the attribute information to be processed.

[0384] For example, the bitstream includes a position parameter set (position PS) including control information for position information at each time, and an attribute parameter set (attribute PS) including control information for attribute information at each time.

[0385] For example, the bitstream includes a position sequence parameter set (position SPS) that includes control information common to position information at multiple times, and an attribute sequence parameter set (attribute SPS) that includes control information common to attribute information at multiple times.

[0386] For example, the bitstream includes a stream parameter set (stream PS) that includes control information common to position information at a plurality of times and attribute information at a plurality of times.

[0387] For example, the bitstream includes an access unit header (AU header) that contains control information that is common within an access unit.

[0388] For example, a three-dimensional data encoding device encodes a group of frames (GOF), which is made up of one or more access units, so that the GOF can be decoded independently. In other words, a GOF is a random access unit.

[0389] For example, the bitstream includes a GOF header that contains control information that is common within a GOF.

[0390] For example, the three-dimensional data encoding device includes a processor and a memory, and the processor performs the above-mentioned processing using the memory.

[0391] As described above, the three-dimensional data decoding device performs the processing shown in Fig. 71. The three-dimensional data decoding device decodes time-series three-dimensional data (for example, point cloud data of a dynamic object). The three-dimensional data includes position information and attribute information for each time. Position information and attribute information for the same time constitute an access unit (AU).

[0392] First, the three-dimensional data decoding device decodes the position information from the bit stream (S4851). That is, the three-dimensional data decoding device generates the position information by decoding the coded position information (coded position data) included in the bit stream.

[0393] Next, the three-dimensional data decoding device decodes the attribute information to be processed from the bit stream by referring to position information at the same time as the attribute information to be processed (S4852). That is, the three-dimensional data decoding device generates attribute information by decoding the coded attribute information (coded attribute data) included in the bit stream. At this time, the three-dimensional data decoding device refers to the decoded position information included in the same access unit as the attribute information.

[0394] This allows the three-dimensional data decoding device to easily control references during decoding using the access unit, thereby reducing the amount of processing required for the decoding process.

[0395] For example, the three-dimensional data decoding device acquires information indicating the location information of the reference destination of the attribute information to be processed from the bit stream, and decodes the attribute information to be processed by referring to the location information of the reference destination indicated in the acquired information.

[0396] For example, the bitstream includes a position parameter set (position PS) including control information for position information at each time, and an attribute parameter set (attribute PS) including control information for attribute information at each time. That is, the three-dimensional data decoding device decodes the position information at the processing target time using the control information included in the position parameter set for the processing target time, and decodes the attribute information at the processing target time using the control information included in the attribute parameter set for the processing target time.

[0397] For example, the bitstream includes a position sequence parameter set (position SPS) including control information common to position information at multiple times, and an attribute sequence parameter set (attribute SPS) including control information common to attribute information at multiple times. That is, the three-dimensional data decoding device decodes the position information at multiple times using the control information included in the position sequence parameter set, and decodes the attribute information at multiple times using the control information included in the attribute sequence parameter set.

[0398] For example, the bitstream includes a stream parameter set (stream PS) including control information common to position information at multiple times and attribute information at multiple times. That is, the three-dimensional data decoding device decodes the position information at multiple times and attribute information at multiple times using the control information included in the stream parameter set.

[0399] For example, the bitstream includes an access unit header (AU header) that includes common control information within the access unit. That is, the 3D data decoding device decodes the position information and attribute information included in the access unit using the control information included in the access unit header.

[0400] For example, a three-dimensional data decoding device independently decodes a group of frames (GOF), which is made up of one or more access units. In other words, a GOF is a random access unit.

[0401] For example, the bitstream includes a GOF header that includes control information common within a GOF. That is, the three-dimensional data decoding device decodes the position information and attribute information included in the GOF using the control information included in the GOF header.

[0402] For example, the three-dimensional data decoding device includes a processor and a memory, and the processor performs the above processing using the memory.

[0403] Although the three-dimensional data encoding device and the three-dimensional data decoding device according to the embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments.

[0404] Furthermore, each processing unit included in the three-dimensional data encoding device and three-dimensional data decoding device according to the above embodiments is typically realized as an LSI, which is an integrated circuit. These may be individually implemented as single chips, or some or all of them may be included in a single chip.

[0405] Furthermore, the integration is not limited to LSI, but may be realized by dedicated circuits or general-purpose processors. FPGAs (Field Programmable Gate Arrays), which can be programmed after LSI fabrication, or reconfigurable processors, which allow the connections and settings of circuit cells within LSIs to be reconfigured, may also be used.

[0406] In each of the above embodiments, each component may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0407] Furthermore, the present disclosure may be realized as a three-dimensional data encoding method or a three-dimensional data decoding method executed by a three-dimensional data encoding device, a three-dimensional data decoding device, or the like.

[0408] The division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as a single functional block, one functional block may be divided into multiple blocks, or some functions may be moved to another functional block.Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in time-sharing by a single piece of hardware or software.

[0409] The order in which the steps in the flowchart are executed is merely an example for specifically explaining the present disclosure, and other orders may be used. Some of the steps may be executed simultaneously (in parallel) with other steps.

[0410] While the three-dimensional data encoding device and three-dimensional data decoding device according to one or more aspects have been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceivable by those skilled in the art to the present embodiments, and configurations constructed by combining components of different embodiments, may also be included within the scope of one or more aspects. [Industrial Applicability]

[0411] The present disclosure is applicable to a three-dimensional data encoding device and a three-dimensional data decoding device. [Explanation of symbols]

[0412] 4601 Three-dimensional data encoding system 4602 Three-dimensional data decoding system 4603 Sensor Terminal 4604 External connection part 4611 Point Cloud Data Generation System 4612 Presentation section 4613 Encoding section 4614 Multiplexer 4615 Input / output section 4616 Control Unit 4617 Sensor information acquisition unit 4618 Point Cloud Data Generation Unit 4621 Sensor Information Acquisition Unit 4622 Input / output section 4623 Demultiplexer 4624 Decoding Unit 4625 Presentation section 4626 User Interface 4627 Control Unit 4630 First Encoding Section 4631 Location information encoder 4632 Attribute information encoder 4633 Additional information coding unit 4634 Multiplexer 4640 First Decoding Unit 4641 Demultiplexer 4642 Location Information Decoding Unit 4643 Attribute Information Decoding Unit 4644 Additional information decoding unit 4650 Second Encoding Section 4651 Additional Information Generation Unit 4652 Position image generation unit 4653 Attribute Image Generation Unit 4654 Video Encoding Unit 4655 Additional information coding unit 4656 Multiplexer 4660 Second Decoding Unit 4661 Demultiplexer 4662 Video Decoding Unit 4663 Additional information decoding unit 4664 Location information generator 4665 Attribute information generation section 4670 Encoding section 4671 Multiplexer 4680 Decoding Unit 4681 Demultiplexer 4710 First Multiplexing Unit 4711 File Conversion Unit 4720 First Demultiplexer 4721 File Reverse Conversion Unit 4730 Second Multiplexing Unit 4731 File Conversion Unit 4740 Second Demultiplexer 4741 File Reverse Conversion Unit 4750 Third Multiplexer 4751 File Conversion Unit 4760 Third Demultiplexer 4761 File Reverse Conversion Unit 4801 Encoding section 4802 Multiplexer

Claims

1. generating a data unit representing a first data type; generating a data unit representing a second data type; generating a data unit representing a third data type; generating a data unit representing a fourth data type; generating information indicating the beginning of each data unit; the data unit indicating the first data type includes encoded position information; the data unit indicating the second data type includes encoded attribute information corresponding to the encoded position information; the data unit indicating the third data type includes a first parameter used in encoding the data unit including the encoded position information; The data unit indicating the fourth data type includes a second parameter used in encoding the data unit including the encoded attribute information. Three-dimensional data encoding method.

2. The data unit including the encoded position information includes a first header and a first payload.

2. The three-dimensional data encoding method according to claim 1.

3. The data unit including the encoded attribute information includes a second header and a second payload.

3. The three-dimensional data encoding method according to claim 2.

4. The data unit including the first parameter includes a third header and a third payload.

4. The three-dimensional data encoding method according to claim 3.

5. The data unit including the second parameter includes a fourth header and a fourth payload.

5. The three-dimensional data encoding method according to claim 4.

6. the data unit indicating the third data type includes a position parameter set; The data unit indicating the fourth data type includes an attribute parameter set.

2. The three-dimensional data encoding method according to claim 1.

7. The data unit indicating the first data type, the data unit indicating the second data type, the data unit indicating the third data type, and the data unit indicating the fourth data type are each a NAL unit. The three-dimensional data encoding method according to any one of claims 1 to 6.

8. The information indicating the beginning of each data unit is stored in the header of each data unit. The three-dimensional data encoding method according to any one of claims 1 to 6.

9. The information indicating the beginning of each data unit is a data unit delimiter. The three-dimensional data encoding method according to any one of claims 1 to 6.

10. The data unit delimiter does not include parameters related to each of the data units.

10. The three-dimensional data encoding method according to claim 9.

11. Decoding a data unit indicative of a first data type; Decoding the data unit indicative of the second data type; decoding the data unit indicative of a third data type; decoding a data unit indicative of a fourth data type; Decode information indicating the beginning of each data unit; the data unit indicating the first data type includes encoded position information; the data unit indicating the second data type includes encoded attribute information corresponding to the encoded position information; the data unit indicating the third data type includes a first parameter used in decoding the data unit including the encoded position information; The data unit indicating the fourth data type includes a second parameter used in decoding the data unit including the encoded attribute information. Three-dimensional data decoding method.

12. The data unit including the encoded position information includes a first header and a first payload. The three-dimensional data decoding method according to claim 11.

13. The data unit including the encoded attribute information includes a second header and a second payload.

13. The three-dimensional data decoding method according to claim 12.

14. The data unit including the first parameter includes a third header and a third payload.

14. The three-dimensional data decoding method according to claim 13.

15. The data unit including the second parameter includes a fourth header and a fourth payload.

15. The three-dimensional data decoding method according to claim 14.

16. the data unit indicating the third data type includes a position parameter set; The data unit indicating the fourth data type includes an attribute parameter set. The three-dimensional data decoding method according to claim 11.

17. The data unit indicating the first data type, the data unit indicating the second data type, the data unit indicating the third data type, and the data unit indicating the fourth data type are each a NAL unit. The three-dimensional data decoding method according to any one of claims 11 to 16.

18. The information indicating the beginning of each data unit is stored in the header of each data unit. The three-dimensional data decoding method according to any one of claims 11 to 16.

19. The information indicating the beginning of each data unit is a data unit delimiter. The three-dimensional data decoding method according to any one of claims 11 to 16.

20. The data unit delimiter does not include parameters related to each of the data units.

20. The three-dimensional data decoding method according to claim 19.

21. a processor; a memory; The processor uses the memory to: generating a data unit representing a first data type; generating a data unit representing a second data type; generating information indicating the beginning of each data unit; generating a data unit including a first parameter used to encode a data unit indicating a third data type; generating a data unit representing a fourth data type; the data unit indicating the first data type includes encoded position information; the data unit indicating the second data type includes encoded attribute information corresponding to the encoded position information; the data unit indicating the third data type includes a first parameter used in decoding the data unit including the encoded position information; The data unit indicating the fourth data type includes a second parameter used in decoding the data unit including the encoded attribute information. Three-dimensional data encoding device.

22. a processor; a memory; The processor uses the memory to: Decoding a data unit indicative of a first data type; Decoding the data unit indicative of the second data type; decoding the data unit indicative of a third data type; decoding a data unit indicative of a fourth data type; Decode information indicating the beginning of each data unit; the data unit indicating the first data type includes encoded position information; the data unit indicating the second data type includes encoded attribute information corresponding to the encoded position information; the data unit indicating the third data type includes a first parameter used in decoding the data unit including the encoded position information; The data unit indicating the fourth data type includes a second parameter used in decoding the data unit including the encoded attribute information. Three-dimensional data decoding device.

Images