A data processing method of a point cloud medium and a related device

Abstract

The embodiment of the application provides a kind of point cloud media data processing method and related equipment, wherein the method comprises: obtaining the media file of point cloud media, the media file includes the point cloud code stream of the point cloud media and cross attribute dependent indication information, the cross attribute dependent indication information is used to indicate the codec dependent relationship between attribute data in the point cloud code stream;According to the cross attribute dependent indication information, the point cloud code stream is decoded to present the point cloud media.The embodiment of the application can guide the transmission, decoding and presentation of point cloud media, support partial transmission and partial decoding at the decoding end, optimize the utilization of network bandwidth and the computing resources of decoding end.

Description

Technical Field

[0001] This application relates to the field of Internet technology, specifically to a data processing method for point cloud media, a data processing device for point cloud media, a computer device, a computer-readable storage medium, and a computer program product. Background Technology

[0002] With the continuous development of point cloud technology, the compression encoding of point cloud media has become an important research issue. Current point cloud encoding supports cross-attribute encoding techniques, allowing for unified encoding of different types of attribute data in point cloud media. However, current cross-attribute encoding techniques still have some problems, such as not supporting partial transmission or partial decoding, and easily causing waste of resources on the decoding side. Therefore, how to improve cross-attribute encoding techniques has become a hot topic in the field of point cloud encoding technology. Summary of the Invention

[0003] This application provides a data processing method and related equipment for point cloud media, which can guide the transmission, decoding and presentation of point cloud media, support partial transmission and partial decoding at the decoding end, and optimize the utilization of network bandwidth and computing resources at the decoding end.

[0004] On one hand, embodiments of this application provide a data processing method for point cloud media, the method comprising:

[0005] Obtain the media file of the point cloud media. The media file includes the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream.

[0006] The point cloud stream is decoded to present point cloud media according to the cross-attribute dependency indication information.

[0007] On one hand, embodiments of this application provide a data processing method for point cloud media, the method comprising:

[0008] Acquire point cloud media and encode the point cloud media to obtain point cloud bitstream;

[0009] Based on the encoding and decoding dependencies between attribute data in the point cloud code stream, cross-attribute dependency indication information is generated;

[0010] The cross-attribute dependency indication information and point cloud code stream are encapsulated to obtain the media file of the point cloud media.

[0011] On one hand, embodiments of this application provide a data processing apparatus for point cloud media, the apparatus comprising:

[0012] The acquisition unit is used to acquire the media file of the point cloud media. The media file includes the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream.

[0013] The processing unit is used to decode the point cloud bitstream according to the cross-attribute dependency indication information to present the point cloud media.

[0014] On one hand, embodiments of this application provide a data processing apparatus for point cloud media, the apparatus comprising:

[0015] The acquisition unit is used to acquire point cloud media;

[0016] The processing unit is used to encode the point cloud media to obtain the point cloud bitstream;

[0017] The processing unit is also used to generate cross-attribute dependency indication information based on the encoding and decoding dependencies between attribute data in the point cloud code stream;

[0018] The processing unit is also used to encapsulate cross-attribute dependency indication information and point cloud bitstream to obtain media files of point cloud media.

[0019] On one hand, embodiments of this application provide a computer device, the computer device comprising:

[0020] A processor is used to execute computer programs;

[0021] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the data processing method for point cloud media as described above.

[0022] On one hand, embodiments of this application provide a computer-readable storage medium storing a computer program that is loaded by a processor and executes the data processing method for point cloud media as described above.

[0023] On one hand, embodiments of this application provide a computer program product, which includes a computer program stored in a computer-readable storage medium. A processor of a computer device reads the computer program from the computer-readable storage medium and executes the computer program, causing the computer device to perform the aforementioned point cloud media data processing method.

[0024] In this embodiment, a media file of point cloud media is obtained. The media file includes the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream. According to the cross-attribute dependency indication information, the point cloud bitstream is decoded to present the point cloud media, thereby guiding the transmission, decoding and presentation of the point cloud media, supporting partial transmission and partial decoding at the decoding end, thereby optimizing the utilization of network bandwidth and computing resources at the decoding end. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1a This is a schematic diagram of a 6DoF provided in an exemplary embodiment of this application;

[0027] Figure 1b This is a schematic diagram of a 3DoF implementation provided in an exemplary embodiment of this application;

[0028] Figure 1c This is a schematic diagram of a 3DoF+ embodiment provided in this application;

[0029] Figure 2a This is an architectural diagram of a point cloud media data processing system provided in an exemplary embodiment of this application;

[0030] Figure 2b This is a flowchart illustrating data processing of point cloud media provided in an exemplary embodiment of this application;

[0031] Figure 3 This is a flowchart illustrating a data processing method for point cloud media provided in an exemplary embodiment of this application;

[0032] Figure 4 This is a flowchart illustrating a data processing method for point cloud media provided in another exemplary embodiment of this application;

[0033] Figure 5 This is a schematic diagram of the structure of a point cloud media data processing device provided in an exemplary embodiment of this application;

[0034] Figure 6 This is a schematic diagram of the structure of a point cloud media data processing device provided in another exemplary embodiment of this application;

[0035] Figure 7 This is a schematic diagram of the structure of a computer device provided in another exemplary embodiment of this application. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function. It should be understood that there is no logical or temporal dependency between "first," "second," and "nth," nor are there any restrictions on quantity or execution order.

[0038] In this application, the term "at least one" means one or more, and "multiple" means two or more; similarly, the term "at least one set" means one or more sets, and "multiple sets" means two or more sets. For example, if a point in a point cloud has multiple sets of attribute data, it means that the point has two or more sets of attribute data.

[0039] The following describes other technical terms used in this application:

[0040] I. Immersive Media

[0041] Immersive media refers to media files that provide immersive content, allowing viewers to experience visual, auditory, and other sensory sensations reminiscent of the real world. Based on the degree of freedom viewers have when consuming the media content, immersive media can be categorized into: 6DoF (Degree of Freedom) immersive media, 3DoF immersive media, and 3DoF+ immersive media. Among these, for example... Figure 1a As shown, 6DoF refers to the ability of viewers of immersive media to freely translate along the X, Y, and Z axes. For example, viewers of immersive media can move freely within 360-degree VR content. Similar to 6DoF are 3DoF and 3DoF+ production techniques. Figure 1b This is a schematic diagram of a 3DoF implementation provided in an embodiment of this application; as shown... Figure 1b As shown, 3DoF refers to the viewer of immersive media being fixed at the center point in a three-dimensional space, while the viewer's head rotates along the X, Y, and Z axes to view the images provided by the media content. Figure 1c This is a schematic diagram of a 3DoF+ embodiment provided in this application, as shown below. Figure 1cAs shown, 3DoF+ refers to the ability of immersive media viewers to move their heads within a limited space based on 3DoF to view the images provided by the media content when the virtual scene provided by the immersive media has a certain depth information.

[0042] II. Point Cloud

[0043] A point cloud is a set of randomly distributed discrete points in space that represent the spatial structure and surface properties of a three-dimensional object or scene. Each point in a point cloud includes at least geometric data, which represents the point's three-dimensional position information. Depending on the application scenario, points in a point cloud may also include one or more sets of attribute data. Each set of attribute data reflects a specific attribute possessed by the point, such as color, material, or other information. Typically, each point in a point cloud has the same number of sets of attribute data.

[0044] Point clouds can flexibly and conveniently represent the spatial structure and surface properties of three-dimensional objects or scenes, and therefore have a wide range of applications. They can be used in virtual reality (VR) games, computer-aided design (CAD), geographic information systems (GIS), autonomous navigation systems (ANS), digital cultural heritage, free-viewpoint broadcasting, 3D immersive remote presentation, and 3D reconstruction of biological tissues and organs.

[0045] Point clouds are primarily acquired through the following methods: computer generation, 3D laser scanning, and 3D photogrammetry. Specifically, point clouds can be obtained by acquiring visual scenes of the real world using acquisition devices (a set of cameras or a camera system with multiple lenses and sensors). 3D laser scanning can obtain point clouds of static 3D objects or scenes in the real world, acquiring millions of point clouds per second; 3D photogrammetry can obtain point clouds of dynamic 3D objects or scenes in the real world, acquiring tens of millions of point clouds per second. Furthermore, in the medical field, point clouds of biological tissues and organs can be obtained through magnetic resonance imaging (MRI), computed tomography (CT), and electromagnetic positioning information. Point clouds can also be directly generated by computers based on virtual 3D objects and scenes. With the continuous accumulation of large-scale point cloud data, the efficient storage, transmission, publication, sharing, and standardization of point cloud data have become crucial for point cloud applications.

[0046] III. Point Cloud Media

[0047] Point cloud media is a typical type of 6DoF immersive media. Point cloud media consists of a sequence of one or more point cloud frames. Each point cloud frame is composed of geometric and attribute data of one or more points in the point cloud. The geometric data, also known as 3D position information, refers to the spatial coordinates (x, y, z) of a point in the point cloud. This can include the coordinate values ​​of the point along each coordinate axis of a 3D coordinate system, such as x (x-axis), y (y-axis), and z (z-axis). A point in the point cloud can include one or more sets of attribute data. Each set of attribute data reflects a specific attribute of the point. For example, a point in the point cloud might have a set of color attribute data reflecting its color attribute (e.g., red, yellow); or a point in the point cloud might have a set of reflectivity attribute data reflecting its laser reflection intensity. When a point in a point cloud has multiple sets of attribute data, the types of these multiple sets of attribute data can be the same or different. For example, a point in a point cloud can have one set of color attribute data and one set of reflectance attribute data; or, a point in a point cloud can have two sets of color attribute data, which are used to reflect the color attributes of the point at different times.

[0048] IV. Track

[0049] A track refers to a collection of media data during the point cloud media encapsulation process. A track consists of multiple time-series samples, and each sample corresponds to a point cloud frame in the point cloud media. Point cloud media encapsulation methods include single-track and multi-track methods. A single-track method encapsulates all point cloud data into a single track, resulting in a media file containing only one track (i.e., a single track obtained through single-track encapsulation). Within this single track, a sample represents a point cloud frame, and each sample contains all the data (including geometric and attribute data) of that frame. A multi-track method encapsulates point cloud data into multiple different tracks, allowing the media file to contain multiple tracks. Furthermore, multi-track methods include type-based and slice-based multi-track methods. Component-type-based multitracking encapsulates one type of data into a single track. For example, point cloud media contains geometric data, a set of color attribute data, and a set of reflectivity attribute data. The geometric data can be encapsulated into a geometry component track, the color attribute data into a color attribute component track, and the reflectivity attribute data into a reflectivity component track. In any track obtained using type-based multitracking, a sample contains only a portion of the data from one point cloud frame of the point cloud media. For instance, a sample in the geometry component track contains the geometric data of one point cloud frame; a sample in the color attribute component track contains a set of color attribute data from one point cloud frame. Specifically, metadata information can also be included as a media type, contained in the point cloud media file as a metadata track. Slice-based multitracking encapsulates one base track and multiple slice tracks. The base track stores the parameter data required for decoding the point cloud media, while the slice tracks store the point cloud media itself. The base track contains one or more samples, each containing the parameter data required for one point cloud frame. A segmented track contains one or more samples, each sample containing point cloud media (including geometric data and / or attribute data) of one or more point cloud slices in a point cloud frame.

[0050] It should be understood that the point cloud media, after being encapsulated, exists in the track as components. For example, attribute data in the point cloud media is encapsulated and exists in the track as attribute components, and geometric data in the point cloud media is encapsulated and exists in the track as geometric components. In subsequent embodiments of this application, the track mentioned can be a single track formed by encapsulating the point cloud stream using a single-track method; or, any track formed by encapsulating the point cloud stream using a type-based multi-track method; or, a basic track formed by encapsulating the point cloud stream using a slice-based multi-track method.

[0051] V. Sample and Subsample

[0052] A sample is a unit of encapsulation in the media file encapsulation process. A track consists of many samples; for example, a video track can consist of many samples, and a sample is usually a video frame. In the embodiments of this application, the media file of point cloud media contains one or more tracks, and one sample in a track corresponds to one point cloud frame.

[0053] A sample can contain one or more point cloud patches (or point cloud strips). A point cloud patch represents a set of syntax elements (e.g., geometric point cloud patches, attribute point cloud patches) of data after a point cloud frame has been partially or fully encoded. Each point cloud patch can be represented by a subsample. Subsamples can be of at least two types: one is a subsample based on the data type carried by the point cloud patch. In this type, a subsample contains only one data type carried by the point cloud patch and related information, such as a subsample containing only geometric data type and geometric data-related information. The other type is a subsample based on the point cloud patch itself. In this type, a subsample can contain all the information of a point cloud patch, i.e., it contains the geometric header and geometric data, and the attribute header and attribute data.

[0054] VI. Sample Entry

[0055] Sample entries are used to indicate metadata information related to all samples in a track. For example, sample entries in a video track typically contain metadata information related to decoder initialization.

[0056] VII. Sample Group

[0057] Sample groups are used to divide a subset of samples in a track into groups according to specific rules. In this application, embodiments involve cross-attribute dependency sample groups, which are obtained by grouping samples in the track according to the encoding / decoding dependencies between attribute data. For example, all samples in the track belonging to dependent attribute data are grouped into one cross-attribute dependency sample group. In this case, the cross-attribute dependency sample group can be used to identify the samples in the track to which the dependent attribute data belongs, and any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data. As another example, all samples in the track belonging to dependent attribute data are grouped into one cross-attribute dependency sample group. In this case, the cross-attribute dependency sample group can be used to identify the samples in the track to which the dependent attribute data belongs. Any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data.

[0058] The term "includes" as mentioned above refers to the attribute data of the point cloud frame contained in any sample within a track obtained using either a single-track or type-based multi-track method. The term "corresponds" as mentioned above refers to the fact that, in a base track obtained using a slice-based multi-track method, any sample does not directly contain the attribute data of the point cloud frame, but rather the parameter data required by the point cloud frame; however, the attribute data of the point cloud frame can be found in the corresponding slice track through the samples in the base track. Therefore, samples in cross-attribute dependent sample groups within the base track can correspond to the dependent attribute data or the corresponding dependent attribute data.

[0059] 8. Point Cloud Spatial Tile:

[0060] Point cloud spatial segmentation is also known as hexahedral spatial segmentation region within the boundary space region of point cloud frame. A point cloud spatial segmentation consists of one or more point cloud pieces, and there is no encoding / decoding dependency between point cloud spatial segments.

[0061] 9. ISOBMFF (ISO Based Media File Format)

[0062] ISOBMFF is a media file encapsulation standard, and a typical ISOBMFF file is an MP4 file.

[0063] 10. DASH (Dynamic Adaptive Streaming over HTTP) is an adaptive bitrate technology that enables high-quality streaming media to be delivered over the Internet through traditional HTTP web servers.

[0064] XI. MPD (Media Presentation Description, media presentation description signaling in DASH):

[0065] MPD is used to describe media segment information in media files.

[0066] 12. Representation:

[0067] A representation refers to a combination of one or more media components in DASH. For example, a video file of a certain resolution can be regarded as a representation. In this application, a video file of a certain temporal level can be regarded as a representation.

[0068] Thirteen, Adaptation Sets: Adaptation Sets refer to a collection of one or more video streams in DASH. An Adaptation Set can contain multiple representations.

[0069] XIV. Point Cloud Compression (PCC)

[0070] Point cloud encoding refers to the process of encoding the geometric and attribute data of each point in a point cloud to obtain a point cloud bitstream. Point cloud encoding can include two main processes: geometric data encoding and attribute data encoding. During the encoding process, G-PCC (Geometry-based Point Cloud Compression) can be used to encode the geometric data of each point in the point cloud media to obtain a geometric bitstream; G-PCC can also be used to encode the attribute data of each point in the point cloud media to obtain an attribute bitstream; the geometric bitstream and the attribute bitstream together constitute the point cloud bitstream of the point cloud media.

[0071] In particular, when encoding multiple types of attribute data, cross-attribute encoding is allowed; for example, attribute data 1 is color attribute data and attribute data 2 is reflectivity attribute data; attribute data 1 can be encoded first, and then attribute data 2 can be encoded.

[0072] The information involved in the encoding process can be stored in a data box for decoding on the decoding side. This data box can be implemented using the syntax shown in Table 1.

[0073] Table 1

[0074]

[0075]

[0076] The semantics of the syntax in Table 1 above are as follows:

[0077] The attribute presence flag field (attributePresentFlag[attrIdx]) is a binary variable. When the attribute presence flag field takes the first set value (e.g., 1), it indicates that the current point cloud bitstream contains the attrIdx attribute code; when it takes the second set value (e.g., 0), it indicates that the current point cloud bitstream does not contain the attrIdx attribute code. attrIdx is an integer between 0 and 15. The meaning of this attribute presence flag field can be found in Table 2 below.

[0078] Table 2, x attribute encoding mapping table

[0079]

[0080]

[0081] Attribute Transform Algorithm Flag Field (transform): This attribute transform algorithm flag field is a binary variable. It controls whether wavelet transform is used to encode the attribute data. When the attribute transform algorithm flag field takes the first preset value (e.g., 1), it controls the use of wavelet transform for encoding the attribute data; when it takes the second preset value (e.g., 0), it controls the use of prediction methods for encoding the attribute data.

[0082] Attribute transformation coefficient quantization parameter difference (attrTransformQpDelta): This attribute transformation coefficient quantization parameter difference is an unsigned integer used to represent the difference between the attribute transformation coefficient quantization parameter and the attribute residual quantization parameter. Attribute transformation coefficient quantization parameter attrTransformQp = attrQuantParam(attribute quantization parameter) + attrTransformQpDelta.

[0083] Attribute Transform Points (attrTransformNumPoints): The attribute transform points are unsigned integers used to represent the number of points used for attribute transformation, i.e., wavelet transform using attrTransformNumPoints points; when attrTransformNumPoints is set to the second preset value (e.g., 0), it means that all points in the chip are used for wavelet transform.

[0084] The maximum search neighbor count logarithm minus seven (maxNumOfNeighbour_log2_minus7): This maximum search neighbor count logarithm minus seven is an unsigned integer used to derive the variable maxNumOfNeighbour (maximum neighbor count), representing the maximum number of encoded neighbors available for searching. This controls the search range of neighbor candidates during attribute prediction and the number of points cached by the hardware. maxNumOfNeighbour is calculated using the following formula:

[0085] maxNumOfNeighbour = 2 (maxNumOfNeighbor_log2_minus7+7) maxNumOfNeighbour_log2_minus7.

[0086] The attribute residual quadratic prediction field (cross_component_pred) is a binary variable used to indicate whether attribute residual quadratic prediction is allowed. When the attribute residual quadratic prediction field takes the first set value (e.g., 1), it means that attribute residual quadratic prediction is allowed. When the attribute residual quadratic prediction field takes the second set value (e.g., 0), it means that attribute residual quadratic prediction is not allowed.

[0087] Residual encoding order switch field (orderSwitch): This residual encoding order switch field is a binary variable; when the value of the residual encoding order switch field is the first set value (such as 1), it indicates that the residual encoding order is UYV / GRB order; when the value of the residual encoding order switch field is the second set value (such as 0), it indicates that the residual encoding order is RGB / YUV order.

[0088] The half-zero runlength_enable flag field is a binary variable. When the value of the half-zero runlength_enable flag field is the first set value, it means that the half-zero runlength is used. When the value of the half-zero runlength_enable flag field is the second set value, it means that the half-zero runlength is not used.

[0089] Chroma channel Cb quantization parameter offset (chromaQpOffsetCb): This chroma channel Cb quantization parameter offset is a signed integer used to control the quantization parameter of the Cb channel, with a value range of -16 to 16. If chromaQpOffsetCb does not exist in the current attribute header information, then the value of chromaQpOffsetCb is 0. That is, chromaQpCb = Clip3(minQP, maxQP, attribute_qp + chromaQpOffsetCb). Note that the quantization parameter lumaQp for the luma channel is attribute_qp, with the minimum supported quantization parameter being minQP = 0 and the maximum supported quantization parameter being maxQP = 63.

[0090] Chroma channel quantization parameter offset (chromaQpOffsetCr): This chroma channel quantization parameter offset is a signed integer. It controls the quantization parameter of the Cr channel, with a value range of -16 to 16. If chromaQpOffsetCr does not exist in the current attribute header information, then the value of chromaQpOffsetCr is 0. That is, chromaQpCr = Clip3(minQP, maxQP, attribute_qp + chromaQpOffsetCr). Note that the quantization parameter lumaQp for the luma channel is attribute_qp, with the minimum supported quantization parameter being minQP = 0 and the maximum supported quantization parameter being maxQP = 63.

[0091] Nearest neighbor prediction parameter 1 (nearestPredParam1): This nearest neighbor prediction parameter 1 is an unsigned integer used to control the threshold for nearest neighbor prediction.

[0092] Nearest neighbor prediction parameter 2 (nearestPredParam2): This nearest neighbor prediction parameter 2 is an unsigned integer used to control the threshold for nearest neighbor prediction; the threshold is expressed as attrQuantParam*nearestPredParam1+nearestPredParam1.

[0093] Spatial bias coefficient (axisBias): This spatial bias coefficient is an unsigned integer used to control the offset in the Z direction during the calculation of attribute prediction values.

[0094] Output BitDepthMinus1: This is an unsigned integer representing the output bit depth of an attribute, and it controls the output bit depth. This value is between 0 and 15. outputBitDepth = outputBitDepthMinus1 + 1. If this syntax element is not in the point cloud code stream, the default value is zero.

[0095] LoD Levels (numOflevelOfDetail): This LoD level is an unsigned integer used to control the number of LOD levels divided during attribute prediction. In the bitstream conforming to this section, numOflevelOfDetail should not exceed 32.

[0096] Maximum number of neighbor points selected for prediction (maxNumOfPredictNeighbours): This maximum number of neighbor points selected for prediction is an unsigned integer used to limit the number of neighbor points selected during attribute prediction. In bitstreams conforming to this section, maxNumOfPredictNeighbours should not exceed 16.

[0097] The LoD intra-layer prediction flag field (intraLodFlag) is a binary variable used to control whether intra-layer prediction is enabled. When the LoD intra-layer prediction flag field is set to the first preset value (e.g., 1), intra-layer prediction is enabled; when the LoD intra-layer prediction flag field is set to the second preset value (e.g., 0), intra-layer prediction is disabled.

[0098] Color Reorder Mode: The color reorder mode is an unsigned integer used to represent the reordering mode of the currently selected color information. When the color reorder mode field is the first preset value (e.g., 0), it represents the original point cloud input order; when the color reorder mode field is the second preset value (e.g., "1"), it represents Hilbert reordering; when the color reorder mode field is the third preset value (e.g., "2"), it represents Morton reordering.

[0099] Reflectance Reordering Mode (colorReorderMode): The reflectance reordering mode is an unsigned integer. When the reflectance reordering mode is the first preset value (e.g., 0), it indicates the original point cloud input order; when the reflectance reordering mode field is the second preset value (e.g., 1), it indicates Hilbert reordering; when the reflectance reordering mode field is the third preset value (e.g., 2), it indicates Morton reordering.

[0100] Maximum cache limit parameter (maxNumofCoeff): This maximum cache limit parameter is an unsigned integer used to calculate the maximum number of transformation parameters that can be cached in attribute transformation coding.

[0101] Maximum Delay Limit Parameter (coeffLengthControl): This maximum delay limit parameter is an unsigned integer used to limit the maximum number of delays for transformation parameters in attribute transformation coding. Specifically, the maximum number of delay points is calculated as maxNumofCoeff * coeffLengthControl.

[0102] Attribute Encoding Order Field (attrEncodeOrder): This field is a binary variable used to control the encoding order of attributes when the point cloud contains multiple attribute types. When the attribute encoding order field is the first set value (e.g., 0), it means that color is encoded first, then reflectance; when the attribute encoding order field is the second set value (e.g., 1), it means that reflectance is encoded first, then color.

[0103] Cross-type attribute prediction field (crossAttrTypePred): This is a binary variable for the cross-type attribute prediction field. When the value of the cross-type attribute prediction field is the first set value (e.g., 1), it means that cross-type attribute prediction is allowed; when the value of the cross-type attribute prediction field is the first set value (e.g., 0), it means that cross-type attribute prediction is not allowed.

[0104] Cross-type attribute prediction weight parameter 1 (crossAttrTypePredParam1): Cross-type attribute prediction weight parameter 1 is a 15-bit unsigned integer used to control the weight parameter 1 for calculating geometric information distance and attribute information distance in cross-type attribute prediction.

[0105] Cross-type attribute prediction weight parameter 2 (crossAttrTypePredParam2): Cross-type attribute prediction weight parameter 2 is a 21-bit unsigned integer used to control the weight parameter 2 for calculating geometric information distance and attribute information distance in cross-type attribute prediction.

[0106] Reflectance Group Prediction Flag Field (refGroupPred): This reflectance group prediction flag field is a binary variable used to control whether the reflectance group prediction mode of the prediction transformation is enabled. When the reflectance group prediction flag field is the first set value (e.g., 1), it means that group prediction is enabled; when the reflectance group prediction flag field is the first set value (e.g., 0), it means that group prediction is disabled.

[0107] Initial Predictive Transform Ratio (initPredTransRatio): This initial predictive transform ratio is a signed integer used in the multi-level transform algorithm for attribute compression (transform=1) to control the size of the initial distance threshold used when constructing the predictive transform tree.

[0108] Transform Residual Layer Flag Field (transResLayer): This transform residual layer flag field is a binary variable used in the multi-layer transform algorithm for attribute compression (transform=1) to control whether attribute residual compensation is used. When transResLayer is the first set value (e.g., 1), it indicates that attribute residual compensation is used; when transResLayer is the second set value (e.g., 0), it indicates that attribute residual compensation is not used.

[0109] Color Golomb Order (ColorGolombNum): This color Golomb order is an unsigned integer used to represent the order K of the K-order exponent Golomb used when decoding the current color prediction residual or transform coefficients, where K = ColorGolombNum.

[0110] Reflectance index Golomb order (RefGolombNum): This reflectance index Golomb order is an unsigned integer used to represent the order K of the K-order exponential Golomb used when decoding the current reflectance prediction residual or transform coefficients, where K = ColorGolombNum.

[0111] The decoding mode flag field of the current coefficient to be decoded (coeffEncodeModeFlag): This decoding mode flag field of the current coefficient to be decoded is a binary variable; when the decoding mode flag field of the current coefficient to be decoded is the first set value (such as 1), it means that the point cloud attribute transformation coefficient is decoded according to 9.3.16.3; when the decoding mode flag field of the current coefficient to be decoded is the first set value (such as 0), it means that the point cloud attribute transformation coefficient is decoded according to 9.3.12.

[0112] 15. Point Cloud Decoding

[0113] Point cloud decoding refers to the process of decoding the point cloud bitstream obtained from point cloud encoding to reconstruct the point cloud. More specifically, it refers to the process of reconstructing the geometric information and attribute data of each point in the point cloud based on the geometric bitstream and attribute bitstream in the point cloud bitstream. After obtaining the point cloud bitstream on the decoding side, for the geometric bitstream, entropy decoding is first performed to obtain the quantized geometric information of each point in the point cloud, and then inverse quantization is performed to reconstruct the geometric information of each point in the point cloud. For the attribute bitstream, entropy decoding is first performed to obtain the quantized prediction residual information or quantized transform coefficients of each point in the point cloud; then, the quantized prediction residual information is inverse quantized to obtain the reconstructed residual information, and the quantized transform coefficients are inverse quantized to obtain the reconstructed transform coefficients. The reconstructed transform coefficients are then inversely transformed to obtain the reconstructed residual information. Based on the reconstructed residual information of each point in the point cloud, the attribute data of each point in the point cloud can be reconstructed. The reconstructed attribute data of each point in the point cloud is then matched one-to-one with the reconstructed geometric data in sequence to reconstruct the point cloud.

[0114] Based on the above description, this application provides a data processing scheme for point cloud media. The general principle of this scheme is as follows: On the encoding side, corresponding cross-attribute dependency indication information can be generated based on the encoding / decoding dependencies between attribute data in the point cloud bitstream during the encoding process. This cross-attribute dependency indication information is then encapsulated in the media file of the point cloud media, indicating the encoding / decoding dependencies between attribute data in the point cloud bitstream. On the decoding side, the point cloud bitstream can be decoded based on the cross-attribute dependency indication information to present the point cloud media. In this data processing scheme, the cross-attribute dependency indication information in the media file of the point cloud media indicates the encoding / decoding dependencies between attribute data in the point cloud bitstream. Based on this indication, the transmission, decoding, and presentation of the point cloud media can be guided, supporting partial transmission and partial decoding on the decoding side, thereby optimizing the utilization of network bandwidth and computing resources on the decoding side.

[0115] It should be noted that attribute data with encoding / decoding dependencies can be divided into dependent attribute data and dependent attribute data based on these dependencies. As the names suggest, dependent attribute data refers to attribute data that needs to rely on other data during the encoding / decoding process; while dependent attribute data refers to data that is relied upon by other data. For example, if the encoding / decoding process of attribute data 1 (Attr1) needs to rely on attribute data 2 (Attr2), then there is an encoding / decoding dependency between attribute data 1 (Attr1) and attribute data 2 (Attr2). Attribute data 1 (Attr1) is called dependent attribute data, and attribute data 2 (Attr2) is called dependent attribute data.

[0116] The point cloud media data processing solution provided in this application embodiment can also be combined with vehicle networking technology. Specifically, the point cloud media data processing solution can collect data on buildings, traffic signs, etc. in the environment, and build a point cloud map in the vehicle for positioning, or use the point cloud map to achieve automatic navigation.

[0117] Based on the above description, the following is combined with Figure 2a A data processing system suitable for implementing the point cloud media provided in the embodiments of this application is described. For example... Figure 2aAs shown, the point cloud media data processing system 20 may include a content production device 201 and a media processing device 202. The content production device 201 is located on the encoding side of the point cloud media; this content production device 201 can be a terminal device or a server. The media processing device 202 is located on the decoding side of the point cloud media; this media processing device 202 can also be a terminal device or a server. A communication connection can be established between the content production device 201 and the media processing device 202. The terminal can be a smartphone, tablet, laptop, desktop computer, smart speaker, smartwatch, vehicle terminal, smart TV, etc., but is not limited to these. The server can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms.

[0118] In one embodiment, the specific process of data processing of the point cloud media by the content production device 201 and the media processing device 202 is as follows: For the content production device 201, the main data processing processes include: (1) the acquisition process of the point cloud media; (2) the encoding and file encapsulation process of the point cloud data. For the media processing device 201, the main data processing processes include: (3) the file decapsulation and decoding process of the point cloud data; (4) the rendering process of the point cloud data.

[0119] In addition, the content production device 201 and the media processing device 202 involve the transmission process of point cloud media. This transmission process can be based on various transmission protocols (or transmission signaling). The transmission protocols here may include, but are not limited to: DASH (Dynamic Adaptive Streaming over HTTP) protocol, HLS (HTTP Live Streaming) protocol, SMTP (Smart Media Transport Protocol), TCP (Transmission Control Protocol), etc.

[0120] The data processing procedure for point cloud media is described in detail below:

[0121] (1) The process of acquiring point cloud media.

[0122] Content creation device 201 can acquire point cloud media, which can be obtained through scene capture or device generation. Scene capture point cloud media refers to obtaining point cloud media by capturing real-world visual scenes through a capture device associated with content creation device 201. The capture device provides point cloud media acquisition services for content creation device 201 and can include, but is not limited to, any of the following: camera equipment, sensing equipment, and scanning equipment. Camera equipment can include ordinary cameras, stereo cameras, and light field cameras, etc. Sensing equipment can include laser equipment, radar equipment, etc. Scanning equipment can include 3D laser scanning equipment, etc. The capture device associated with content creation device 201 can refer to hardware components installed in content creation device 201, such as a terminal camera or sensor. The capture device associated with content creation device 201 can also refer to hardware devices connected to content creation device 201, such as a camera connected to content creation device 201. Device generation point cloud media refers to content creation device 201 generating point cloud media based on virtual objects (such as virtual 3D objects and virtual 3D scenes obtained through 3D modeling).

[0123] (2) The process of encoding and file encapsulation of point cloud media.

[0124] The content production device 201 can use point cloud encoding to encode the geometric and attribute data in the acquired point cloud media to obtain a point cloud bitstream (including encoded geometric bitstream and attribute bitstream). Optionally, when encoding the attribute data in the point cloud media, cross-attribute encoding can be performed on multiple types of attribute data; for example, attribute data 1 in the point cloud media is a set of color attribute data, and attribute data 2 is a set of reflectivity attribute data; in the cross-attribute encoding process, attribute data 1 can be encoded first, and then attribute data 2 can be encoded.

[0125] After obtaining the point cloud stream, cross-attribute dependency indication information can be generated based on the encoding and decoding dependencies between attribute data in the point cloud stream. This cross-attribute dependency indication information and the point cloud stream are then encapsulated to obtain a media file of the point cloud media. During encapsulation, either a single-track or multi-track approach can be used. When encapsulating the point cloud stream using a single-track approach, a single track is obtained. This single track can include one or more samples, each of which can contain all the data from a point cloud frame in the point cloud media, including geometric data and attribute data. Furthermore, multi-track approaches include type-based and slice-based approaches. When encapsulating the point cloud stream using a type-based approach, multiple tracks are obtained. Any track can include one or more samples, each of which can contain a type of data from a point cloud frame in the point cloud media. For example, a sample in track 1 (geometric component track) can contain the geometric data from the corresponding point cloud frame, and a sample in track 2 (color component track) can contain a set of color attribute data from the corresponding point cloud frame. When a point cloud bitstream is encapsulated using a slice-based multi-track method, multiple tracks are obtained (including a base track and multiple slice tracks). The base track contains the parameter data required for point cloud media decoding. The point cloud data (including geometric data and attribute data) of the point cloud frame can be found from the corresponding slice track through the samples in the base track.

[0126] After encapsulating the cross-attribute dependency indication information and the point cloud stream to obtain a media file, the media file can be transmitted to the media processing device 202, whereby the media processing device 202 can decode the point cloud stream according to the cross-attribute dependency indication information. The cross-attribute dependency indication information can be set at the sample entry of a track in the media file, or at the entry of a cross-attribute dependency sample group contained in a track in the media file. Here, a track can be a single track formed by encapsulating the point cloud stream using a single-track method; or any track formed by multi-track encapsulating the point cloud stream using a type-based multi-track method; or a basic track formed by multi-track encapsulating the point cloud stream using a slice-based multi-track method. Unless otherwise specified, the track mentioned in subsequent embodiments of this application has the same meaning as the track mentioned here.

[0127] Optionally, when point cloud media is transmitted using streaming, cross-attribute dependency indication information can be included in the transmission signaling.

[0128] (3) The process of decapsulating and decoding point cloud media files;

[0129] Media processing device 202 can obtain the media files and corresponding media presentation description information of point cloud media from content production device 201. The media files and media presentation description information of the point cloud media are transmitted from content production device 201 to media processing device 202 via transmission signaling (such as DASH, SMT). The file decapsulation process of media processing device 202 is the reverse of its file encapsulation process; media processing device 202 decapsulates the media file resources according to the file format requirements of point cloud media to obtain the point cloud bitstream. The decoding process of media processing device 202 is the reverse of its encoding process of content production device 201; media processing device 202 decodes the encoded bitstream to reconstruct the point cloud media.

[0130] During the decoding process, the media processing device 202 can obtain cross-attribute dependency indication information from the media file or transmission signaling, and can obtain the media file of the point cloud media as needed based on the cross-attribute dependency indication information, and decode the point cloud media as needed.

[0131] (4) The rendering process of point cloud media.

[0132] The media processing device 202 renders the decoded point cloud media according to the metadata related to rendering and windowing in the media presentation description information, obtains the point cloud frames of the point cloud media, and presents the point cloud media according to the presentation time of the point cloud frames.

[0133] In one embodiment, see Figure 2bOn the content production device side: First, the visual scene A of the real world is sampled by the acquisition device to obtain the point cloud source data B of the point cloud media corresponding to the visual scene of the real world. The point cloud source data B is a frame sequence composed of a large number of point cloud frames. Then, the acquired point cloud media is encoded to obtain the point cloud bitstream E (including the encoded geometric bitstream and attribute bitstream). Next, the point cloud bitstream E is encapsulated to obtain the media file corresponding to the point cloud media. Specifically, the content production device 201 combines one or more encoded bitstreams into a media file F for file playback, or an initialization segment and a sequence of media segments (FS) for streaming transmission, according to a specific media container file format. The media container file format can refer to the ISO basic media file format specified in International Organization for Standardization (ISO) / International Electrotechnical Commission (IEC) 14496-12. In one implementation, the content production device also encapsulates metadata into a media file or a sequence of initialization / media segments, and transmits the sequence of initialization / media segments to the media processing device 202 via transmission signaling (such as a dynamic adaptive streaming media transmission interface).

[0134] At the media processing device: First, the device receives a media file sent by the content creation device 201. This media file may include a media file F' for file playback, or an initialization segment and a sequence of media segments Fs' for streaming. Then, the media file is decapsulated to obtain a point cloud stream E'. Next, based on the cross-attribute dependency indication information contained in the media file or transmission signaling, the point cloud stream is decoded (i.e., the attribute data in the point cloud stream can be decoded based on the cross-attribute dependency indication information) to obtain point cloud media D'. In specific implementation, the media processing device determines the media file or media segment sequence required for presenting the point cloud media based on the current viewing position / viewing direction of the object. It then decodes the media file or media segment sequence required for presenting the point cloud media to obtain the point cloud media required for presentation. Finally, based on the current viewing (window) direction of the object, the decoded point cloud media is rendered to obtain a point cloud frame A', and the point cloud media is presented on the screen of the head-mounted display or any other display device carried by the media processing device according to the presentation time of the point cloud frame. It should be noted that the current viewing position / direction of the object is determined by head following and possibly visual following functionality. In addition to rendering the point cloud media of the current object's viewing position / direction using a renderer, an audio decoder can also be used to decode and optimize the audio in the current object's viewing (viewport) direction. Furthermore, during viewport-based transmission, the current viewing position and direction are also passed to the strategy module to determine the track to be received.

[0135] It is understood that the data processing technology of point cloud media involved in this application can be implemented based on cloud technology; for example, using a cloud server as a content production device. Cloud technology refers to a hosting technology that unifies a series of resources such as hardware, software, and networks within a wide area network or local area network to realize the computation, storage, processing, and sharing of data.

[0136] In this embodiment, the content production device can acquire point cloud media and encode it to obtain a point cloud bitstream. Then, based on the encoding / decoding dependencies between attribute data in the point cloud bitstream, cross-attribute dependency indication information is generated. The cross-attribute dependency indication information and the point cloud bitstream are encapsulated to obtain a media file of the point cloud media. The media processing device can then acquire the media file and decode the point cloud bitstream based on the cross-attribute dependency indication information included in the media file. By adding cross-attribute dependency indication information to the media file of the point cloud media to indicate the encoding / decoding dependencies between attribute data in the point cloud bitstream, the transmission, decoding, and presentation of the point cloud media can be guided based on this indication, supporting partial transmission and partial decoding at the decoding end, thereby optimizing the utilization of network bandwidth and the computing resources of the decoding end.

[0137] The data processing method for point cloud media provided in the embodiments of this application will be described below. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a flowchart illustrating a point cloud media data processing method provided in an embodiment of this application. This point cloud media data processing method can be executed by a media processing device in a point cloud media data processing system. The method includes the following steps S301-S302:

[0138] S301. Obtain the media files of the point cloud media.

[0139] The media file includes the point cloud stream of the point cloud media and cross-attribute dependency indication information. The point cloud stream is obtained by encoding the point cloud media; the cross-attribute dependency indication information is used to indicate the encoding and decoding dependencies between attribute data in the point cloud stream. For example, the cross-attribute dependency indication information can be used to indicate the encoding and decoding dependencies between attribute data 1 and attribute data 2 in the point cloud stream (such as attribute data 1 depending on attribute data 2 during encoding and decoding).

[0140] The methods for setting cross-attribute dependency indication information in the media files of point cloud media can include the following (1)-(6):

[0141] (1) Cross-attribute dependency indication information can be set at the sample entry of the track.

[0142] The media file includes tracks, each containing one or more samples. Each sample corresponds to a point cloud frame in the point cloud media. When a point cloud stream is encapsulated using a single track, the track involved in this embodiment refers to a single track formed by encapsulating the point cloud stream using a single track. In this case, one sample corresponds to all the data of a point cloud frame in the point cloud media, including geometric data and attribute data. A set of attribute data can be used to reflect a type of attribute of a point, and the type of attribute may include, but is not limited to, color, reflectivity, and material. When a point cloud stream is encapsulated using a type-based multitrack method, the track involved in this embodiment refers to any track formed by encapsulating the point cloud stream using a multitrack method. In this case, the samples in the track correspond to a type of data of a point cloud frame in the point cloud media, such as the samples in the track corresponding to the attribute data of a point cloud frame in the point cloud media. When a point cloud stream is encapsulated using a slice-based multitrack method, the track involved in this embodiment refers to a basic track formed by encapsulating the point cloud stream using a slice-based multitrack method.

[0143] The aforementioned cross-attribute dependency indication information can be set in the sample entry of the track. This cross-attribute dependency indication information can be used to indicate that the encoding and decoding dependencies between attribute data in the point cloud code stream remain consistent across all samples in the track. "Consistent" means that the encoding and decoding dependencies between attribute data included in all samples of the track do not change. For example, if all samples contain a set of attribute data 1 and a set of attribute data 2 of the same type, and the cross-attribute dependency indication information is set in the sample entry of the track, then it indicates that the encoding and decoding dependencies between attribute data in the point cloud code stream are attribute data 1 dependent on attribute data 2 across all samples in the track. As another example, if each sample contains a set of color attribute data and a set of reflectance attribute data, and the cross-attribute dependency indication information is set in the sample entry of the track, then it indicates that the encoding and decoding dependencies between attribute data in the point cloud code stream are color attribute data dependent on reflectance attribute data across all samples in the track.

[0144] It should be understood that the encoding and decoding dependencies between attribute data can include: encoding and decoding dependencies between attribute data of the same type, such as color attribute data 1 depending on color attribute data 2, and reflectivity attribute data 1 depending on reflectivity attribute data 2; or, encoding and decoding dependencies between attribute data can include: encoding and decoding dependencies between attribute data of different types, such as color attribute data depending on reflectivity attribute data.

[0145] (2) Cross-attribute dependency indication information can be set in the cross-attribute dependency sample group.

[0146] The media file includes tracks, each containing cross-attribute dependency sample groups. Each cross-attribute dependency sample group contains one or more samples, with each sample corresponding to a point cloud frame in the point cloud media. In one embodiment, the cross-attribute dependency sample group can be used to identify the sample to which the dependent attribute data belongs. The significance of the cross-attribute dependency sample group is that, for a certain attribute data 1 (denoted as Attr1), among multiple samples in a point cloud stream, some samples may be dependent on samples to which other attribute data belongs, while some samples may not be dependent on these other attribute data samples. This can be distinguished by the cross-attribute dependency sample group. It can be understood that any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data. In this case, the samples corresponding to the attribute data to which other attribute data depends will be classified into a cross-attribute dependency sample group. For example, sample 1 contains attribute data 2 to which attribute data 1 (i.e., other attribute data) depends, and sample 2 also contains attribute data 2 to which attribute data 1 depends. Samples 1 and 2 can be classified into a cross-attribute dependency sample group.

[0147] In another embodiment, the cross-attribute dependency sample group can be used to identify the sample to which the dependent attribute data belongs. The significance of the cross-attribute dependency sample group is that, for a certain attribute data 2 (denoted as Attr2), among multiple samples in a point cloud stream, some samples may depend on samples to which other attribute data belongs, while some samples may not depend on these other attribute data samples. This can be distinguished by the cross-attribute dependency sample group. It can be understood that any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data; in this case, the samples corresponding to the attribute data to which other attribute data depends will be classified into a cross-attribute dependency sample group. For example, sample 1 contains attribute data 1 that depends on attribute data 2 (i.e., other attribute data), and sample 2 contains attribute data 3 that depends on attribute data 2. Samples 1 and 2 can be classified into a cross-attribute dependency sample group.

[0148] At this point, cross-attribute dependency indication information can be set in the entry point of the cross-attribute dependency sample group. This cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependencies between attribute data in the point cloud stream change across all samples in the track. "Change" means that the encoding and decoding dependencies between attribute data included in all samples of the track will change or differ in different samples. For example, the track includes two samples, and all samples may contain attribute data 1, attribute data 2, and attribute data 3; the encoding and decoding dependencies between attribute data in the point cloud stream in sample 1 might be attribute data 1 depending on attribute data 2, and the encoding and decoding dependencies between attribute data in the point cloud stream in sample 2 might be attribute data 2 depending on attribute data 3.

[0149] In this embodiment, cross-attribute indication information can be represented as a cross-attribute dependency information data box. This cross-attribute indication information can indicate the encoding dependency relationship between different groups of attribute data in the point cloud code stream:

[0150] In one implementation, cross-attribute dependency indication information can be used to indicate the encoding / decoding dependency relationship between two or more sets of attribute data in a point cloud code stream. For example, if attribute data 1 is dependent on attribute data 3 and attribute data 4, then the cross-attribute dependency indication information can be used to indicate the encoding / decoding dependency relationship between these three sets of attribute data. In one implementation, the cross-attribute dependency indication information can be represented as a cross-attribute dependency information data box, which contains at least one of the following fields: the number of dependent attribute data, the identifier of the dependent attribute data, the number of dependent attribute data, and the identifier of the dependent attribute data. The data box type of the cross-attribute dependency information data box is 'cadi', and the cross-attribute dependency information data box is included in the sample entry, with a mandatory type of 'no'; the quantity is 0 or 1. The syntax of the cross-attribute dependency information data box can be found in Table 3.

[0151] Table 3

[0152]

[0153] The semantics of each field contained in the cross-attribute dependency information data box are as follows:

[0154] The `depended_attr_num` field indicates the number of sets of dependent attribute data contained in or corresponding to the current track; or, it indicates the number of sets of dependent attribute data contained in or corresponding to the current sample. The number of sets of dependent attribute data refers to the number of sets of attribute data that are depended upon by other data. For example, the current track or sample may contain two sets of attribute data that are depended upon by attribute data 1, meaning there are two sets of attribute data that are depended upon by attribute data 1 in the current track or sample. The current track refers to the track being decoded in the media file, and the current sample refers to the sample being decoded in the current track.

[0155] The field `depending_attr_num` indicates the number of other attribute data sets that depend on the current attribute data. The current attribute data refers to the attribute data being decoded in the current sample.

[0156] Depended attribute data identifier field (depended_attr_id): This dependent attribute data identifier field is used to indicate the identifier of the attribute data that is depended on, that is, the identifier of the attribute data that is depended on by other data.

[0157] Dependency attribute data identifier field (depending_attr_id): This dependency attribute data identifier field is used to indicate the identifiers of other attribute data that depend on the current attribute data.

[0158] In another implementation, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two sets of attribute data in the point cloud code stream, that is, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two attribute data in the point cloud code stream; for example, there is an encoding and decoding dependency relationship between attribute data 1 and attribute data 2, and there is an encoding and decoding dependency relationship between attribute data 3 and attribute data 4.

[0159] At this point, the cross-attribute dependency information data box includes a field for the number of dependent attribute data, a field for the identifier of the dependent attribute data, and a field for the identifier of the dependent attribute data; the syntax of the above cross-attribute dependency information data box can be found in Table 4:

[0160] Table 4

[0161]

[0162] The semantics of each field contained in the cross-attribute dependency information data box are as follows:

[0163] The `depended_attr_num` field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbital. Alternatively, it indicates the number of sets of dependent attribute data contained in or corresponding to the current sample.

[0164] Dependency attribute data identifier field (depended_attr_id): This dependency attribute data identifier field is used to indicate the identifier of the attribute data that is dependent on any two sets of attribute data.

[0165] The dependent attribute data identifier field (depending_attr_id) is used to indicate the identifier of the dependent attribute data in any two sets of attribute data.

[0166] In another embodiment, the point cloud stream contains only attribute data of the first type and attribute data of the second type. For example, the point cloud stream contains only reflectance attribute data (i.e., attribute data of the first type) and color attribute data (i.e., attribute data of the second type). In this case, cross-attribute dependency indication information is used to indicate the encoding / decoding dependency relationship between the attribute data of the first type and the attribute data of the second type; this cross-attribute dependency information data box may contain a dependent attribute data type field (depended_attr_type): this attribute data type field is used to indicate the data type of the dependent attribute. The syntax of this cross-attribute dependency information data box is shown in Table 5:

[0167] Table 5

[0168]

[0169] Wherein, if the aforementioned dependent attribute data type field is a first value (e.g., 0), it indicates that the attribute data of the first type is dependent on the attribute data of the second type; if the aforementioned dependent attribute data type field is a second value (e.g., 1), it indicates that the attribute data of the second type is dependent on the attribute data of the first type. It should be noted that the first and second values ​​can be set according to requirements, for example, the first value can be set to 1 and the second value can be set to 0; this application does not limit this.

[0170] (3) Cross-attribute dependency indication information can be set in the track group.

[0171] In one embodiment, dependencies between tracks can be established based on attribute data with encoding / decoding dependencies in the point cloud stream. The media file may include one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud stream can reside in different attribute component tracks. For example, if the attribute data with encoding / decoding dependencies in the point cloud stream are color attribute data and reflectance attribute data, the color attribute data can be placed in one attribute component track, and the reflectance attribute data in another. In this case, the association between different attribute component tracks can be represented using track groups, where the association can be understood as an encoding / decoding dependency.

[0172] The media file contains a track group type data box, which can be used to indicate the attribute component track to which attribute data with encoding / decoding dependencies in the point cloud bitstream belongs. Cross-attribute dependency indication information can be set in the track group type data box, and this cross-attribute dependency indication information can be represented as a cross-attribute dependency information data box (CrossAttrDependencyInfoBox). The syntax of the track group type data box (TrackGroupTypeBox) is shown in Table 6:

[0173] Table 6

[0174]

[0175] (4) Cross-attribute dependency indication information can be a track identifier, which can be set in the attribute component track to which the dependent attribute data belongs.

[0176] The media file includes one or more attribute component tracks, where attribute data with encoding / decoding dependencies in the point cloud stream are located on different attribute component tracks; the media file includes a track reference type data box, which includes a track identifier that indicates the attribute component track to which the attribute data that the attribute data with encoding / decoding dependencies belongs; the track reference type data box is set in the attribute component track to which the attribute data that the attribute data with encoding / decoding dependencies belongs.

[0177] In one implementation, the track identifier can indicate the track identifier of the attribute component track to which the dependent attribute data belongs. This attribute component track refers to the attribute component track to which attribute data dependent on other attribute data belongs. For example, attribute data 1 and attribute data 2 have an encoding / decoding dependency relationship, and attribute data 1 is dependent on attribute data 2. Attribute data 1 and attribute data 2 are located in different attribute component tracks. Then, a track reference type box is set in the attribute component track to which attribute data 2 belongs, and the track identifier is used to indicate the attribute component track to which the dependent attribute data 1 belongs. This track reference type box is a TrackReferenceTypeBox, and a track identifier of type 'cadr' is added to this track reference type box. If the current attribute component track contains a track identifier, it means that at least one sample in the current attribute component track depends on at least one sample in the attribute component track indicated by the track identifier during decoding.

[0178] In another implementation, the track identifier is used to indicate the attribute component track to which the dependent attribute data in the attribute data with encoding / decoding dependencies belongs; the track reference type data box is set in the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependencies belongs; if the current attribute component track contains a track identifier, then at least one sample in the current attribute component track is dependent on at least one sample in the attribute component track indicated by the track identifier; wherein, the current attribute component track refers to the attribute component track being decoded. For example, attribute data 1 and attribute data 2 have encoding / decoding dependencies, and attribute data 1 is dependent on attribute data 2, and attribute data 1 and attribute data 2 are located in different attribute component tracks; then, the track reference type box is set in the attribute component track to which attribute data 1 belongs, and the track identifier is used to indicate the attribute component track to which the dependent attribute data 2 belongs. The track reference type data box is a TrackReferenceTypeBox, and a track identifier of type 'cadr' is added to this track reference type data box. If the current attribute component track contains a track identifier, it means that at least one sample in the current attribute component track is dependent on at least one sample in the attribute component track indicated by the track identifier.

[0179] (5) Cross-attribute dependency indication information can be set in the subsample information data box.

[0180] The media file includes a track containing one or more samples, each sample corresponding to a point cloud frame in the point cloud media; a sample is divided into one or more point cloud slices, each point cloud slice being represented by a subsample; cross-attribute dependency indication information is set in the subsample information data box. In this case, the cross-attribute dependency indication information can be included in the subsample information data box, and this cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field.

[0181] Specifically, when encapsulating point cloud code streams, subsample information data boxes can be used. These subsample information data boxes can contain a flag field for the subsample information data. Subsamples can be defined based on the value of this flag field (flag). The flag field specifies the type of subsample information in the subsample information data box: If the flag field is a first preset value (e.g., 0), then the subsample refers to a subsample based on the data type carried by the point cloud patch. In this case, a subsample contains only one data type and related data, such as a subsample containing only geometric data type and geometric data. If the flag field is a second preset value (e.g., 1), then the subsample refers to a subsample based on a point cloud patch. In this case, a subsample contains only all the related data of one point cloud patch, i.e., it contains the geometric patch header and geometric data, and the attribute patch header and attribute data. Of course, the flag field can retain other flag values.

[0182] At this point, the definition of the codec_specific_parameters field in the subsample information data box can be as shown in Table 7:

[0183] Table 7

[0184]

[0185]

[0186] The meanings of the fields included in the subsample information data box are as follows:

[0187] PayloadType field: This payload field indicates the data type of the point cloud patch contained in the subsample. If the value of the payloadType field is the first set value (e.g., 0), it means that the data type of the point cloud patch contained in the subsample is attribute data. If the value of the payloadType field is the second set value (e.g., 1), it means that the data type of the point cloud patch contained in the subsample is geometric data.

[0188] The attribute_present_flag field indicates whether the subsample contains color and / or reflectance attributes. The definition can be found in AVS (Audio Video Coding Standard) - PCC. If the attribute_present_flag field has a first set value (e.g., 0), it indicates whether the subsample contains color attributes; if the attribute_present_flag field has a second set value (e.g., 1), it indicates whether the subsample contains reflectance attributes.

[0189] Slice_data field: This field indicates whether the subsample contains slice data. If the value of the slice data field is the first set value (e.g., 1), it indicates that the subsample contains slice geometry and / or attribute type data; if the value of the slice data field is the second set value (e.g., 0), it indicates that the subsample does not contain point cloud parameter information.

[0190] Slice ID field: This field indicates the identifier of the slice corresponding to the data contained in the subsample.

[0191] Cross-attribute dependency flag field (cross_attr_depending_flag): This cross-attribute dependency flag field indicates whether the current attribute data depends on other attribute data during decoding. If the value of the cross-attribute dependency flag field is the first preset value (e.g., 1), it means that the current attribute data depends on other attribute data during decoding; if the value of the cross-attribute dependency flag field is the second preset value (e.g., 0), it means that the current attribute data does not depend on other attribute data during decoding.

[0192] Attribute Identifier Field (attr_id): This field is used to indicate the identifier of the current attribute data, which is the attribute data in the subsample being decoded in the media file.

[0193] In this embodiment, the media file may further include a component information data box, which contains the type of the component in the track; if the component type is attribute data, the component information data box also includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, which refers to the attribute data being decoded. The syntax of this component information data box can be found in Table 8.

[0194] Table 8

[0195]

[0196] The definitions of the fields contained in the component's information data box are as follows:

[0197] Audio / video encoding standard point cloud compression type field (avs_pcc_type): This field indicates the type of component in the track. The values ​​of this field are shown in Table 9 below: When the value of avs_pcc_type is 4, it can be determined that the component type in the track is attribute data.

[0198] Table 9

[0199] 1 reserved 2 geometric data 3 reserved 4 attribute data 5..31 reserved

[0200] Attribute Count field (attr_num): This field indicates the number of attribute components contained in the track.

[0201] Attribute type field (attr_type): This field indicates the type of attribute component contained in the track. The attribute type field takes the first value (e.g., 0), indicating that the attribute component contained in the track is of the color attribute type; the attribute type field takes the second value (e.g., 1), indicating that the attribute component contained in the track is of the reflectivity attribute type.

[0202] Attribute Identifier Field (attr_id): This field indicates the identifier of the current attribute data, which refers to the identifier of the attribute data currently being decoded.

[0203] In one embodiment, obtaining the media file of point cloud media may include: receiving the media file of point cloud media sent by a content production device. Alternatively, when the point cloud media is transmitted using a streaming transmission method, obtaining the media file of the point cloud media may also be achieved by: obtaining the transmission signaling of the point cloud media, and then obtaining the media file of the point cloud media based on the transmission signaling. The transmission signaling may be a DASH signaling or an SMT signaling. Based on this, embodiments of this application may also include cross-attribute dependency indication information in the transmission signaling to achieve decoding processing of the point cloud bitstream based on the cross-attribute dependency indication information.

[0204] The embodiments of this application can extend fields at the encapsulation level to support the implementation steps of the embodiments of this application. When point cloud media is transmitted using streaming transmission, fields can also be extended at the transmission signaling level to support the embodiments of this application.

[0205] (6) Cross-attribute dependency indication information can be set in the transmission signaling.

[0206] a. When the transmission instruction is a DASH instruction, the cross-attribute dependency indication information can refer to the cross-attribute dependency information descriptor in the DASH signaling.

[0207] This cross-attribute dependency information descriptor can be used to indicate the encoding / decoding dependencies between attribute data in a point cloud bitstream or the dependencies between different attribute data during cross-attribute encoding of point cloud media. Specifically, this cross-attribute dependency information descriptor (CrossAttrDependencyInfo descriptor) can be a SupplementalProperty element, and its @schemeIdUri attribute is "urn:avs:ims:2022:apcc". This cross-attribute dependency information descriptor can exist in any level, including the adaptation set level, the representation level, and the preselection level. When a cross-attribute dependency information descriptor exists in the adaptive set hierarchy, it is used to describe all representations in the adaptive set hierarchy; when a cross-attribute dependency information descriptor exists in the representation hierarchy, it is used to describe the representation in the corresponding representation hierarchy; when a cross-attribute dependency information descriptor exists in the preselected hierarchy, it is used to describe the point cloud media corresponding to the preselected hierarchy.

[0208] The cross-attribute dependency information descriptor includes at least one of the following elements: cross-attribute dependency information (CrossAttrDependencyInfo), a dependent attribute data identifier element (@depended_attr_id), a dependent attribute data type element (@depended_attr_type), a dependent attribute data identifier element (@depending_attr_id), and a dependent attribute data type element (depending_attr_type). The cross-attribute dependency information element can be used to indicate the encoding / decoding dependency relationship between different attribute data in a point cloud code stream during cross-attribute encoding. The dependent attribute data identifier element indicates the identifier of the dependent attribute data. The dependent attribute data identifier element indicates the identifier of other attribute data that depends on the current attribute data. The dependent attribute data type element indicates the type of the dependent attribute data. The dependent attribute data type element indicates the type of other attribute data that depends on the current attribute data. The cross-attribute dependency information descriptor can be as shown in Table 10.

[0209] Table 10 Elements and attributes of the Geometric Compression MultiAttrInsInfo descriptor

[0210]

[0211] Where M: Mandatory field; CM: Conditional Mandatory field; O: Optional field.

[0212] Optionally, b. When the transmission instruction is DASH signaling, the cross-attribute dependency indication information can also refer to the dependency identifier field in the DASH signaling; the dependency identifier field can be @dependencyId in the DASH signaling. This dependency identifier field is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud code stream. Specifically, in attribute data with encoding and decoding dependency relationships, the dependency identifier field can be set in the representation corresponding to the dependent attribute data. This dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data (i.e., the attribute data that is depended on by other attribute data).

[0213] c. The transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the STM signaling.

[0214] In SMT, Asset group descriptors are defined to indicate the relationships between Assets within the same SMT Package. Originally, SMT only had four relationship types: dependency, composition, equivalence, and similarity, with corresponding flags (dependency_flag, composition_flag, equivalence_flag, and similarity_flag, respectively). A new relationship type added in SMT is the non-aligned time-segment knowledge bitstream dependency relationship, with the corresponding flag being the library_flag. This relationship type describes the dependency between the current Asset and non-aligned time-segment knowledge bitstream Assets. The syntax of the Asset group descriptor can be found in Table 11.

[0215] Table 11 Asset Group Descriptor Syntax

[0216]

[0217]

[0218] The meanings of the fields included in the Asset group descriptor are as follows:

[0219] Descriptor tag field: This 16-bit field indicates the tag value for this type of descriptor.

[0220] Descriptor length field (descriptor_length): This field is 16 bits and indicates the length of this descriptor in bytes, calculated from the next field to the last field.

[0221] Dependency Flag field: This field is 1 bit and indicates whether a dependency needs to be added to this descriptor. A value of 0 in the dependency flag field is the first default value, meaning that no dependency needs to be added.

[0222] Composition flag field: This field is 1 bit. It indicates whether a composition relationship needs to be added in this descriptor. A value of 0 in the composition flag field is the first preset value, meaning that no composition relationship needs to be added.

[0223] Equivalence_flag: This field is a single bit and indicates whether an equivalence relation needs to be added to this descriptor. A value of 0 for the equivalence_flag field is the first preset value, meaning that no equivalence relation needs to be added.

[0224] Similarity flag field: This field is a single bit and indicates whether a similarity relationship needs to be added to this descriptor. A value of 0 for the similarity flag field is the first preset value, meaning that no similarity relationship needs to be added.

[0225] Library flag field (library_flag): This field is 1 bit and indicates whether non-aligned time-period knowledge bitstream dependencies need to be added in this descriptor. A value of the library flag field is the first preset value (e.g., 0), meaning that no non-aligned time-period knowledge bitstream dependencies need to be added.

[0226] The num_dependencies field: This 8-bit field indicates the number of assets that the asset described by this descriptor depends on.

[0227] The number of combinations field (num_compositions) is an 8-bit field that indicates the number of assets that are combined with the asset described by this descriptor.

[0228] The equivalence_selection_level field: This 8-bit field indicates the presentation level of the corresponding Asset within the equivalence group. A first value ('0') in the equivalence_selection_level field indicates that the Asset is presented by default. When the default Asset cannot be selected, the Asset with the lower presentation level will be selected and presented as a substitute.

[0229] The num_equivalences field is an 8-bit field that indicates the number of assets that are equivalent to the asset described by this descriptor.

[0230] The similarity selection level field (similarity_selection_level) is an 8-bit field that indicates the presentation level of the corresponding asset within the similarity group. A value of '0' in the similarity selection level field indicates that the asset is presented by default. When the default asset cannot be selected, the asset with the lower presentation level will be selected and presented as a substitute.

[0231] The number of similarities field (num_similarities) is an 8-bit field that indicates the number of assets that are similar to the asset described by this descriptor.

[0232] The number of libraries (num_libraries) field: This 8-bit field indicates the number of non-aligned time-series knowledge bitstream assets that the asset described by this descriptor depends on.

[0233] Asset Identifier Field (asset_id): This field indicates the identifier of the Asset, i.e., the asset_id in the Asset group descriptor: When the Asset group descriptor is used to indicate a dependency, the asset_id field indicates the identifier of the Asset that the Asset described by this descriptor depends on. The order of the Asset identifiers provided in this descriptor corresponds to its internal encoded dependency hierarchy. When the Asset group descriptor is used to indicate a composition relationship, the asset_id field indicates the identifier of the Asset that has a composition relationship with the Asset described by this descriptor. When the Asset group descriptor is used to indicate an equivalence relationship, the asset_id field indicates the identifier of the Asset that has an equivalence relationship with the Asset described by this descriptor. When the Asset group descriptor is used to indicate a similarity relationship, the asset_id field indicates the identifier of the Asset that has a similarity relationship with the Asset described by this descriptor. When the Asset group descriptor is used to indicate a knowledge bitstream dependency relationship with a non-aligned time period, the asset_id field indicates the identifier of the Asset that has a knowledge bitstream dependency relationship with the Asset described by this descriptor with a non-aligned time period.

[0234] In one embodiment, regarding the SMT signaling description described above, this application embodiment can utilize the Asset group descriptor in the SMT signaling to indicate the encoding / decoding dependencies between different attribute data. Specifically, the cross-attribute dependency indication information includes an Asset group descriptor, which is used to indicate the encoding / decoding dependencies between attribute data in the point cloud bitstream.

[0235] In the context of attribute data with encoding / decoding dependencies, the asset group descriptor is set within the asset corresponding to the dependent attribute data. This asset group descriptor can include a dependency flag, a dependency quantity field (num_dependencies), and an asset ID field (asset_id). The dependency flag is set to a first preset value (e.g., 1). The dependency quantity field indicates the number of other attribute data groups that the dependent attribute data needs to depend on during decoding. The asset ID field indicates the asset ID corresponding to the dependent attribute data; in other words, it indicates the asset ID corresponding to the attribute data that is depended on by other attribute data.

[0236] It is understandable that the cross-attribute dependency indication information setting methods shown in (1)-(6) above can be flexibly selected and used or combined according to the actual situation. For example, cross-attribute dependency indication information can be set in the sample entry of the track. When the track has sub-sample division, cross-attribute dependency indication information can be further set in the sub-sample information data box.

[0237] S302. Decode the point cloud stream according to the cross-attribute dependency indication information to present the point cloud media.

[0238] The media processing device can obtain cross-attribute dependency indication information from the media file or read it from the transmission signaling. When obtaining cross-attribute dependency indication information from the media file, the media processing device can obtain the cross-attribute dependency indication information from the sample entry of the track, the cross-attribute dependency sample group, or the sub-sample in the media file.

[0239] In one embodiment, step S302 can be implemented as follows: the media processing device can determine the attribute data that the current attribute data depends on based on the encoding / decoding dependency relationship indicated by the cross-indication dependency information; then decode the attribute data that the current attribute data depends on; and after decoding the attribute data that the current attribute data depends on, decode the current attribute data.

[0240] The media processing device can determine the attribute data that the current attribute data depends on based on the encoding / decoding dependency relationship indicated by the cross-indication dependency information by: determining the decoding order of the attribute data in the point cloud bitstream based on the encoding / decoding dependency relationship indicated by the cross-indication dependency information, and determining the attribute data that the current attribute data depends on from the decoding order.

[0241] It should be understood that when the media processing device reads cross-attribute dependency indication information from the transmission signaling, it determines the attribute data that needs to be decoded and the attribute data that the current attribute data depends on based on the cross-attribute dependency indication information. At this time, it is necessary to decode the dependent attribute data first and then decode the current attribute data. Since the media file is transmitted through streaming, the media processing device needs to request the data stream (i.e., the media file) corresponding to the dependent attribute data from the content production device to achieve the first decoding of the dependent attribute data. Through the cross-attribute dependency indication information, the corresponding data stream of the attribute data can be obtained as needed to achieve transmission guidance for the media file corresponding to the point cloud media.

[0242] In this embodiment, the media processing device can acquire a media file of point cloud media, the media file including the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream. According to the cross-attribute dependency indication information, the point cloud bitstream is decoded to present the point cloud media. The cross-attribute dependency indication information is added to the media file of the point cloud media to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream. Based on this indication, the transmission, decoding and presentation of the point cloud media can be guided, supporting partial transmission and partial decoding at the decoding end, thereby optimizing the utilization of network bandwidth and computing resources at the decoding end.

[0243] Please see Figure 4 , Figure 4 This is a flowchart illustrating a point cloud media data processing method provided in an embodiment of this application. The method can be executed by a content production device. The point cloud media data processing method described in this embodiment may include the following steps S401-S403:

[0244] S401. Acquire point cloud media and encode the point cloud media to obtain point cloud bitstream.

[0245] The specific implementation method for encoding point cloud media can be found in the description of the corresponding section above, and will not be repeated here.

[0246] S402. Generate cross-attribute dependency indication information based on the encoding and decoding dependencies between attribute data in the point cloud code stream.

[0247] This cross-attribute dependency information can be represented as a cross-attribute dependency information data box. The encoding / decoding dependencies between attributes in a point cloud bitstream can include the following:

[0248] (1) There are encoding / decoding dependencies between two or more sets of attribute data in the point cloud code stream. For example, there are encoding / decoding dependencies between three sets of attribute data in the point cloud code stream, such as attribute data 1, attribute data 2, and attribute data 3, where attribute data 1 is dependent on attribute data 2 and attribute data 3. In this case, the cross-attribute dependency indication information can indicate the encoding / decoding dependencies between two or more sets of attribute data in the point cloud code stream. The aforementioned cross-attribute dependency information data box can contain at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data. Among them, the number of dependent attribute data is used to indicate the number of sets of attribute data contained in or corresponding to the current track that are dependent on other attribute data; or, the number of dependent attribute data is used to indicate the number of sets of dependent attribute data contained in or corresponding to the current sample; the identifier of dependent attribute data is used to indicate the identifier of the dependent attribute data; the number of dependent attribute data is used to indicate the number of sets of other attribute data that depend on the current attribute data; and the identifier of dependent attribute data is used to indicate the identifier of other attribute data that depend on the current attribute data. Here, the current track refers to the track being encoded, the current sample refers to the sample being encoded in the current track, and the current attribute data refers to the attribute data being encoded in the current sample.

[0249] (2) There is an encoding / decoding dependency relationship between any two sets of attribute data in the point cloud code stream. For example, any two sets of attribute data are attribute data 1 and attribute data 2, and attribute data 1 is dependent on attribute data 2. In this case, the cross-attribute dependency indication information can indicate the encoding / decoding dependency relationship between any two sets of attribute data in the point cloud code stream. The aforementioned cross-attribute dependency information data box can include a dependent attribute data quantity field, a dependent attribute data identifier field, and a dependent attribute data identifier field; the dependent attribute data quantity field is used to indicate the number of sets of dependent attribute data contained in the current track; or, the dependent attribute data quantity field is used to indicate the number of sets of dependent attribute data contained in or corresponding to the current sample; the dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data in any two sets of attribute data; the dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data in any two sets of attribute data.

[0250] (3) The point cloud stream contains only attribute data of the first type and attribute data of the second type. For example, in the point cloud stream, reflectivity attribute data is dependent on color attribute data. In this case, cross-attribute dependency indication information is used to indicate the encoding / decoding dependency relationship between the attribute data of the first type and the attribute data of the second type. The cross-attribute dependency information data box mentioned above may contain the attribute data type field of the dependent attribute. According to the encoding / decoding dependency relationship between attribute data in the point cloud stream, generating cross-attribute dependency indication information may include: if the attribute data of the first type is dependent on the attribute data of the second type, then the attribute data type field of the dependent attribute is set to a first value (such as 0); if the attribute data of the second type is dependent on the attribute data of the first type, then the attribute data type of the dependent attribute is set to a second value (such as 0).

[0251] S403. Encapsulate the cross-attribute dependency indication information and the point cloud code stream to obtain the media file of the point cloud media.

[0252] The encapsulation of cross-attribute dependency indication information and point cloud bitstream to obtain point cloud media data can include the following implementation methods:

[0253] (1) Encapsulate the point cloud code stream into a track. The track contains one or more samples, and one sample corresponds to a point cloud frame in the point cloud media. If the cross-attribute dependency indication information indicates that the encoding and decoding dependency relationship between the attribute data in the point cloud code stream is consistent in all samples of the track, the cross-attribute dependency indication information can be set in the sample entry of the track to form the media file of the cloud media.

[0254] (2) Encapsulate the point cloud stream into a track, which contains one or more samples, and one sample corresponds to a point cloud frame in the point cloud media; divide the track into cross-attribute dependency sample groups, which contain one or more samples, and any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data; or any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data; if the cross-attribute dependency indication information indicates that the encoding and decoding dependency relationship between the attribute data in the point cloud stream changes in all samples of the track, then set the cross-attribute dependency indication information in the entry of the cross-attribute dependency sample group to form a media file of the point cloud media.

[0255] (3) Encapsulate the attribute data with encoding and decoding relationship in the point cloud code stream into different attribute component tracks. Each attribute component track can contain one or more samples, and each sample corresponds to a point cloud frame in the point cloud media. Each attribute component track can include a type of attribute data or a set of attribute data with encoding and decoding relationship. Then, the relationship between different attribute component tracks is represented by track groups to form a media file of the point cloud media.

[0256] The media file may contain a track group type data box, which is used to indicate the attribute component track to which attribute data with encoding and decoding dependencies in the point cloud bitstream belongs; the cross-attribute dependency information data box is set in the track group type data box.

[0257] (4) Encapsulate the attribute data with encoding / decoding relationships in the point cloud bitstream into different attribute component tracks; then determine the track identifier corresponding to the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs; in one embodiment, the track identifier can be used to indicate the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs, and then put the track identifier into a track reference type box; finally, set the track reference type box in the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs, forming a media file of the point cloud media. Wherein, if the current attribute component track contains a track identifier, then at least one sample in the current attribute component track depends on at least one sample in the attribute component track indicated by the track identifier during encoding.

[0258] In another implementation, a track identifier is used to indicate the attribute component track to which the dependent attribute data in the attribute data with encoding / decoding dependencies belongs; a track reference type data box is set in the attribute component track to which the dependent attribute data in the attribute data with encoding / decoding dependencies belongs; if the current attribute component track contains a track identifier, then at least one sample in the current attribute component track is dependent on at least one sample in the attribute component track indicated by the track identifier; wherein, the current attribute component track refers to the attribute component track being decoded.

[0259] (5) The point cloud stream can be encapsulated into a track, which contains one or more samples, and one sample corresponds to a point cloud frame in the point cloud media; then a sample is divided into one or more point cloud pieces, and each point cloud piece is represented by a sub-sample; then, cross-attribute dependency indication information is set in the sub-sample to form a media file of the point cloud media.

[0260] When encapsulating the point cloud code stream using a SubSampleInformationBox, cross-attribute dependency indication information can be set in the SubSampleInformationBox.

[0261] In one embodiment, the cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field. Generating the cross-attribute dependency indication information based on the encoding / decoding dependencies between attribute data in the point cloud stream may include: if the encoding / decoding dependencies between attribute data in the point cloud stream include the current attribute data depending on other attribute data during encoding, then setting the cross-attribute dependency flag field to a first preset value; if the encoding / decoding dependencies between attribute data in the point cloud stream include the current attribute data not depending on other attribute data during encoding, then setting the cross-attribute dependency flag field to a second preset value; wherein, the attribute data identifier field is used to indicate the identifier of the current attribute data, which is the attribute data being encoded.

[0262] In one embodiment, the media file further includes a component information data box containing the types of components in the track; if the type of a component is attribute data, the component information data box further includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, which refers to the attribute data being encoded.

[0263] After encapsulating the cross-attribute dependency indication information and the point cloud bitstream to obtain the point cloud media file, when the media file is transmitted using streaming, the cross-attribute dependency indication information is included in the transmission signaling, and then the media file of the point cloud media is transmitted through the transmission signaling. The transmission signaling can be DASH signaling or SMT signaling.

[0264] (1) When the transmission signaling is DASH signaling, the cross-attribute dependency indication information can refer to the cross-attribute dependency information descriptor in DASH signaling or the dependency identifier field in DASH signaling.

[0265] In one embodiment, generating cross-attribute dependency indication information based on the encoding / decoding dependencies between attribute data in the point cloud code stream may include: generating a cross-attribute dependency information descriptor based on the encoding / decoding dependencies between attribute data in the point cloud code stream.

[0266] This cross-attribute dependency information descriptor can be used to indicate the encoding / decoding dependencies between attribute data in a point cloud bitstream or the dependencies between different attribute data during cross-attribute encoding of point cloud media. Specifically, this cross-attribute dependency information descriptor (CrossAttrDependencyInfo descriptor) can be a SupplementalProperty element, and its @schemeIdUri attribute is "urn:avs:ims:2022:apcc". This cross-attribute dependency information descriptor can exist in any level, including the adaptation set level, the representation level, and the preselection level. When a cross-attribute dependency information descriptor exists in the adaptive set hierarchy, it is used to describe all representations in the adaptive set hierarchy; when a cross-attribute dependency information descriptor exists in the representation hierarchy, it is used to describe the representation in the corresponding representation hierarchy; when a cross-attribute dependency information descriptor exists in the preselected hierarchy, it is used to describe the point cloud media corresponding to the preselected hierarchy.

[0267] The cross-attribute dependency information descriptor includes at least one of the following elements: cross-attribute dependency information (CrossAttrDependencyInfo), a dependent attribute data identifier element (@depended_attr_id), a dependent attribute data type element (@depended_attr_type), a dependent attribute data identifier element (@depending_attr_id), and a dependent attribute data type element (depending_attr_type); wherein, the cross-attribute dependency information element can be used to indicate the encoding and decoding dependency relationship between different attribute data in the point cloud code stream during cross-attribute encoding; the dependent attribute data identifier element is used to indicate the identifier of the dependent attribute data; the dependent attribute data identifier element is used to indicate the identifier of other attribute data that depends on the current attribute data; the dependent attribute data type element is used to indicate the type of the dependent attribute data; and the dependent attribute data type element is used to indicate the type of other attribute data that depends on the current attribute data.

[0268] In another embodiment, the cross-attribute dependency indication information can refer to the dependency identifier field in the DASH signaling. The dependency identifier field is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud code stream. Specifically, in attribute data with encoding and decoding dependencies, the dependency identifier field is set in the representation corresponding to the dependent attribute data. This dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data.

[0269] (2) When the transmission signaling is SMT signaling, the cross-attribute dependency indication information refers to the asset group descriptor in the STM signaling.

[0270] The above-mentioned generation of cross-attribute dependency indication information based on the encoding and decoding dependencies between attribute data in the point cloud code stream may include: generating an asset group descriptor based on the encoding and decoding dependencies between attribute data in the point cloud code stream.

[0271] Specifically, in attribute data with encoding / decoding dependencies, the asset group descriptor is set within the asset corresponding to the dependent attribute data. This asset group descriptor includes a dependency flag, a dependency quantity field, and an asset identifier field; the dependency flag is set to a first preset value, the dependency quantity field indicates the number of other attribute data groups that the dependent attribute data needs to depend on during encoding, and the asset identifier field indicates the asset identifier corresponding to the dependent attribute data.

[0272] In this embodiment, point cloud media is acquired and encoded to obtain a point cloud bitstream; cross-attribute dependency indication information is generated based on the encoding / decoding dependency relationship between attribute data in the point cloud bitstream; the cross-attribute dependency indication information and the point cloud bitstream are encapsulated to obtain a media file of the point cloud media; by generating the cross-attribute dependency indication information, it is convenient to guide the decoding of the point cloud bitstream.

[0273] The following two complete examples illustrate in detail the data processing method for point cloud media provided in this application:

[0274] Example 1: Include a CrossAttrDependencyInfoBox in the track sample entry point.

[0275] 1. Content production equipment can acquire point cloud media and encode the point cloud media to generate point cloud bitstreams.

[0276] 2. When encapsulating the point cloud code stream into a file, cross-attribute dependency indication information is generated based on the encoding and decoding dependencies of different attribute data in the point cloud code stream during encoding and decoding. Then, the point cloud code and cross-attribute dependency indication information are encapsulated into a file using a single-track method to obtain a media file.

[0277] The media file contains a track (track1), which includes geometric data, color attribute data, and reflectance attribute data. This track contains multiple samples, each of which can contain geometric data, color attribute data, and reflectance attribute data. The cross-attribute dependency indication information (represented as a cross-attribute dependency information data box) indicates that the reflectance attribute data depends on the color attribute data during encoding and decoding. This dependency relationship (i.e., reflectance attribute data depends on color attribute data during encoding and decoding) remains unchanged across all samples, so the cross-attribute dependency information data box can be set in the track sample entry. Each sample is divided into one or more point cloud patches, and each point cloud patch is represented by a sub-sample. The cross-attribute dependency indication information can also be set in the sub-sample information data box, ultimately forming the point cloud media file, as follows:

[0278] Track1:

[0279] CrossAttrDependencyInfoBox:

[0280] {depended_attr_num=1; dependent_attr_id=100; depending_attr_num=1; depending_attr_id=200;}

[0281] SubsampleInformationBox:

[0282] Subsample1{cross_attr_depending_flag=0; attr_id=100;}

[0283] Subsample2{cross_attr_depending_flag=1;attr_id=200;}

[0284] The CrossAttrDependencyInfoBox represents a cross-attribute dependency information data box. In this cross-attribute dependency information data box: depended_attr_num=1 indicates that the number of attribute data (i.e., attribute data of identifier 100) that the current orbit or current sample depends on is 1; depended_attr_id=100 indicates that the identifier of the attribute data that depends on the current attribute data is 100; depending_attr_num=1 indicates that the number of other attribute data that depends on the current attribute data is 1; depending_attr_id=200 indicates that the identifier of other attribute data that depends on the current attribute data is 200.

[0285] The SubsampleInformationBox represents the subsample information data box. Within this box: For subsample 1, cross_attr_depending_flag = 0 indicates that the current attribute data does not depend on other attribute data during decoding, and attr_id = 100 indicates that the identifier of the current attribute data is 100. This means that the current attribute data in subsample 1 can be decoded independently. For subsample 2, cross_attr_depending_flag = 1 indicates that the current attribute data depends on other attribute data during decoding, and attr_id = 200 indicates that the identifier of the current attribute data is 200. This means that the current attribute data in subsample 2 depends on other attribute data during decoding (i.e., it depends on the attribute data corresponding to attr_id = 100).

[0286] It should be understood that only two subsamples from a single sample are given here as examples; the fields in the remaining samples are similar.

[0287] 3. Content creation equipment can transfer media files to media processing equipment.

[0288] 4. After receiving the media file, the media processing device can read the CrossAttrDependencyInfoBox and SubsampleInformationBox information from the track sample entry included in the media file. From the CrossAttrDependencyInfoBox and SubsampleInformationBox information, it can be seen that the attribute data of attr_id=200 depends on the attribute data of attr_id=100 during decoding. At the same time, the media file only includes one track, indicating that it is a point cloud bitstream encapsulated in a single-track manner.

[0289] 5. If the media processing device needs to partially decode different attribute data, it can determine the subsample corresponding to attr_id=100 in the sample first and then the subsample corresponding to attr_id=200 in the sample when parsing subsamples based on the encoding and decoding dependency relationship (i.e., attribute data attr_id=200 depends on attribute data attr_id=100 during decoding).

[0290] 6. The media processing device can decode the sub-sample corresponding to attr_id=100 to obtain the attribute data (i.e., point cloud media) in the sub-sample corresponding to attr_id=100, and then decode the sub-sample corresponding to attr_id=200 to obtain the attribute data (i.e., point cloud media) in the sub-sample corresponding to attr_id=200.

[0291] 7. Render the decoded point cloud media to present the point cloud media.

[0292] Example 2: Include CrossAttrDependencyInfoBox in cross-attribute dependency sample groups

[0293] 1. Content production equipment can acquire point cloud media and encode it to generate point cloud bitstreams. During file encapsulation of the point cloud bitstream, cross-attribute dependency indication information is generated based on the encoding / decoding dependencies of different attribute data within the point cloud bitstream. Then, a multi-track approach is used to encapsulate the point cloud bitstream and the cross-attribute dependency indication information to obtain the media file.

[0294] Specifically, point cloud media includes geometric data, color attribute data, and reflectance attribute data. When encapsulating the point cloud stream using a multi-track approach, the geometric data, color attribute data, and reflectance attribute data can each be encapsulated into a separate track, resulting in a geometric component track (Track1), an attribute component track corresponding to the color attribute data (Track2), and an attribute data track corresponding to the reflectance attribute data (Track3). Furthermore, the generated cross-attribute dependency indication information indicates that the reflectance attribute data in samples 1-100 depends on the color attribute data during encoding and decoding; while the reflectance attribute data in samples 101-200 does not depend on the color attribute data during encoding (i.e., it can be decoded independently). Therefore, the cross-attribute dependency indication information can be set in the cross-attribute dependency sample group within the attribute track corresponding to the color attribute data, and this cross-attribute dependency indication information is represented as a cross-attribute dependency information data box. Then, when color attribute data and reflectance attribute data with encoding / decoding dependencies are located on different attribute component tracks, track identifiers can be used to associate the attribute component track corresponding to the color attribute data and the attribute component track corresponding to the reflectance attribute data. The track identifier of the attribute component track corresponding to the color attribute data is set in the track reference type data box of the attribute component track corresponding to the color attribute data, ultimately forming the following media file:

[0295] Track1: Geometry component track

[0296] Track2: Property Component Track - Color

[0297] The CrossAttrDependencyInfoEntry sample group corresponds to sample1 to sample100, and the CrossAttrDependencyInfoBox information contained in this CrossAttrDependencyInfoEntry is as follows:

[0298] {depended_attr_num=1; dependent_attr_id=100; depending_attr_num=1; depending_attr_id=200;}

[0299] The CrossAttrDependencyInfoEntry sample group represents a cross-attribute dependency sample group. Samples 1 to 100 in this cross-attribute dependency sample group are reflectance attribute data that depends on color attribute data during encoding and decoding. This cross-attribute dependency sample group includes a cross-attribute dependency information data box (CrossAttrDependencyInfoBox). depends_attr_num = 1 indicates that the number of attribute data (i.e., color attribute data) that is depended on by other attribute data (i.e., reflectance attribute data) in the current sample is 1. depends_attr_id = 100 indicates that the identifier of the attribute data that is depended on by other attribute data is 100. depending_attr_num = 1 indicates that the number of other attribute data that depends on the current attribute data is 1. depending_attr_id = 200 indicates that the identifier of other attribute data that depends on the current attribute data is 200.

[0300] Track3: Property Component Track - Reflectivity

[0301] The TrackReferenceBox of the track contains a TrackReferenceTypeBox of type 'cadr'. The track ID in the TrackReferenceTypeBox is the ID of Track2, indicating that the current track (Track3) depends on Track2 during decoding.

[0302] Here, TrackReferenceBox represents the track reference data box, and TrackReferenceTypeBox represents the track reference type data box. The track identifier included in the track reference type data box is the ID of Track2 (i.e., the track identifier of track2).

[0303] 2. The aforementioned media files are transmitted via streaming. The track identifier in the track reference type data box can be read to determine the encoding / decoding dependency between track2 and track3. The content production device can transmit the point cloud media files to the media processing device via DASH signaling. In the signaling file, the dependency identifier field (dependencyId) in DASH can be used to index the representation corresponding to track3 to the representation corresponding to track2.

[0304] 3. The media processing device receives the media file of the point cloud media transmitted by the DASH signaling. According to the encoding and decoding dependency relationship indicated in the DASH signaling, it can determine the attribute data that needs to be decoded and the attribute data that the attribute data to be decoded depends on. After step 2 above, the media processing device knows that there is an encoding and decoding dependency relationship between track2 and track3 according to the encoding and decoding dependency relationship indicated in the DASH signaling. Therefore, when it is necessary to present the reflectivity attribute data, the representation corresponding to track2 must be obtained at the same time.

[0305] 4. After the media processing device obtains the representations corresponding to track2 and track3, by parsing the information in the cross-attribute dependent sample group CrossAttrDependencyInfoEntry, it can be determined that the samples in sample1 to 100 are all reflectance attribute data dependent on color data processing, while the color attribute data and reflectance attribute data in the samples in sample101 to 200 can be decoded independently.

[0306] 5. Based on the encoding / decoding dependencies indicated in the cross-attribute dependency information data box, when decoding samples 1-100, first decode samples 1-100 in the attribute component track corresponding to the color attribute data to obtain the color attribute data. Then decode samples 1-100 in the attribute component track corresponding to the reflectance attribute data to obtain the reflectance attribute data. When decoding samples 101-200, the attribute data in the corresponding attribute component track can be decoded as needed.

[0307] 6. Render the decoded color attribute data and reflectivity attribute data to present point cloud media.

[0308] In this embodiment of the application, cross-attribute dependency indication information is added to the media file of the point cloud media to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream. Based on this indication, the transmission, decoding and presentation of the point cloud media can be guided, supporting partial transmission and partial decoding at the decoding end, thereby optimizing the utilization of network bandwidth and computing resources at the decoding end.

[0309] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of a point cloud media data processing device provided in an embodiment of this application. The point cloud media data processing device can be installed in the computer equipment provided in the embodiment of this application. The computer equipment can be the media processing equipment mentioned in the above method embodiment. Figure 5 The data processing device for point cloud media shown can be a computer program (including program code) running on a computer device, and the data processing device for point cloud media can be used to execute... Figure 3 Some or all of the steps in the method embodiments shown. Please refer to [link / reference]. Figure 5 The data processing device for the point cloud media may include the following units:

[0310] The acquisition unit 501 is used to acquire the media file of the point cloud media. The media file includes the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream.

[0311] Processing unit 502 is used to decode the point cloud bitstream according to cross-attribute dependency indication information to present point cloud media.

[0312] In one embodiment, the media file includes a track containing one or more samples, with each sample corresponding to a point cloud frame in the point cloud media.

[0313] Cross-attribute dependency indication information is set in the sample entry of the track. Cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependencies between attribute data in the point cloud code stream remain consistent across all samples of the track.

[0314] In one embodiment, the media file includes a track containing a cross-attribute-dependent sample group, which contains one or more samples, one sample corresponding to a point cloud frame in the point cloud media; any sample in the cross-attribute-dependent sample group contains or corresponds to the dependent attribute data; or, any sample in the cross-attribute-dependent sample group contains or corresponds to the dependent attribute data.

[0315] Cross-attribute dependency indication information is set in the entry of cross-attribute dependency sample group. Cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependencies between attribute data in point cloud code streams change in all samples of the track.

[0316] In one embodiment, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in a point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data.

[0317] The "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbit, or the "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current sample; the "Identifier of Dependent Attribute Data" field indicates the identifier of the dependent attribute data; the "Number of Dependent Attribute Data" field indicates the number of sets of other attribute data that depend on the current attribute data; the "Identifier of Dependent Attribute Data" field indicates the identifier of other attribute data that depend on the current attribute data.

[0318] Here, the current track refers to the track being decoded in the media file, the current sample refers to the sample being decoded in the current track, and the current attribute data refers to the attribute data being decoded in the current sample.

[0319] In one embodiment, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two sets of attribute data in the point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which includes a field for the number of dependent attribute data, a field for the identifier of dependent attribute data, and a field for the identifier of dependent attribute data.

[0320] The "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbit, or the "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current sample; the "Dependent Attribute Data Identifier" field indicates the identifier of the dependent attribute data in any two sets of attribute data; the "Dependent Attribute Data Identifier" field indicates the identifier of the dependent attribute data in any two sets of attribute data.

[0321] Here, the current track refers to the track in the media file that is being decoded, and the current sample refers to the sample in the current track that is being decoded.

[0322] In one embodiment, the point cloud code stream contains only attribute data of the first type and attribute data of the second type; cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between the attribute data of the first type and the attribute data of the second type; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains the attribute data type field of the dependent attribute.

[0323] If the data type field of the dependent attribute is the first value, it means that the attribute data of the first type is dependent on the attribute data of the second type.

[0324] If the data type field of the dependent attribute is the second value, it means that the attribute data of the second type is dependent on the attribute data of the first type.

[0325] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud bitstream are located in different attribute component tracks;

[0326] The relationships between different attribute component tracks are represented by track groups.

[0327] In one embodiment, the media file includes a track group type data box, which is used to indicate the attribute component track to which attribute data with encoding / decoding dependencies in the point cloud bitstream belongs;

[0328] Cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which is set in the track group type data box.

[0329] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud bitstream are located in different attribute component tracks;

[0330] The media file contains a track reference type data box, which includes a track identifier. The track identifier is used to indicate the attribute component track to which the attribute data that is depended upon in the attribute data with encoding and decoding dependencies belongs.

[0331] The track reference type data box is set in the attribute component track to which the attribute data that has encoding and decoding dependencies belongs;

[0332] If the current property component track contains a track identifier, then at least one sample in the current property component track depends on at least one sample in the property component track indicated by the track identifier during decoding.

[0333] The current property component track refers to the property component track that is being decoded.

[0334] In one embodiment, the track identifier is used to indicate the attribute component track to which the dependent attribute data in the attribute data with encoding / decoding dependencies belongs; the track reference type data box is set in the attribute component track to which the dependent attribute data in the attribute data with encoding / decoding dependencies belongs;

[0335] If the current property component track contains a track identifier, then at least one sample in the current property component track is dependent on at least one sample in the property component track indicated by the track identifier;

[0336] The current property component track refers to the property component track that is being decoded.

[0337] In one embodiment, the media file includes a track containing one or more samples, with each sample corresponding to a point cloud frame in the point cloud media.

[0338] A sample is divided into one or more point cloud patches, and each point cloud patch is represented by a subsample.

[0339] Cross-attribute dependency indication information is set in the subsample information data box.

[0340] In one embodiment, the cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field;

[0341] If the cross-attribute dependency flag field is the first preset value, it indicates that the current attribute data depends on other attribute data during decoding;

[0342] If the cross-attribute dependency flag field is the second preset value, it indicates that the current attribute data does not depend on other attribute data during decoding;

[0343] The attribute data identifier field is used to indicate the identifier of the current attribute data;

[0344] Here, the current attribute data refers to the attribute data in the subsample being decoded.

[0345] In one embodiment, the media file includes a track containing one or more samples, with each sample corresponding to a point cloud frame in the point cloud media.

[0346] The media file also includes a component information data box, which contains the type of the component in the track; if the component type is attribute data, the component information data box also includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, which refers to the attribute data being decoded.

[0347] In one embodiment, the point cloud media is transmitted using streaming; when acquiring the media file of the point cloud media, the acquisition unit 501 may specifically be used for:

[0348] Obtain the transmission signaling of the point cloud media, which contains cross-attribute dependency indication information;

[0349] The media files of the point cloud media are obtained based on the transmission signaling.

[0350] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in the DASH signaling;

[0351] When cross-attribute dependency information descriptors exist in the adaptive set hierarchy, they are used to describe all representations in the adaptive set hierarchy;

[0352] When a cross-attribute dependency information descriptor exists in a representation hierarchy, the cross-attribute dependency information descriptor is used to describe the representation in the corresponding representation hierarchy.

[0353] When a cross-attribute dependency information descriptor exists in a preselected level, the cross-attribute dependency information descriptor is used to describe the point cloud media corresponding to the preselected level.

[0354] In one embodiment, the cross-attribute dependency information descriptor includes at least one of the following elements: the dependent attribute data identifier element, the dependent attribute data type element, the dependent attribute data identifier element, and the dependent attribute data type element;

[0355] The dependent attribute data identifier element is used to indicate the identifier of the attribute data that is depended upon; the dependent attribute data type element is used to indicate the type of the attribute data that is depended upon; the dependent attribute data identifier element is used to indicate the identifier of other attribute data that depends on the current attribute data; the dependent attribute data type element is used to indicate the type of other attribute data that depends on the current attribute data.

[0356] The current attribute data refers to the attribute data that is being decoded.

[0357] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the dependency identifier field in the DASH signaling;

[0358] In attribute data with encoding / decoding dependencies, the dependency identifier field is set in the representation corresponding to the dependent attribute data. The dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data.

[0359] In one embodiment, the transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the SMT signaling;

[0360] In attribute data with encoding / decoding dependencies, the asset group descriptor is set in the asset corresponding to the dependent attribute data. The asset group descriptor includes a dependency flag, a dependency quantity field, and an asset identifier field.

[0361] The dependency flag is set to the first preset value; the dependency quantity field is used to indicate the number of other attribute data sets that the dependent attribute data needs to depend on during decoding; the asset identifier field is used to indicate the asset identifier corresponding to the dependent attribute data.

[0362] In one embodiment, when the processing unit 502 decodes the point cloud code stream according to the cross-attribute dependency indication information, it may specifically be used to:

[0363] Based on the encoding / decoding dependencies indicated by the cross-attribute dependency indication information, determine the attribute data that the current attribute data depends on;

[0364] Decode the attribute data that the current attribute data depends on;

[0365] After decoding the attribute data that the current attribute data depends on, the current attribute data is then decoded.

[0366] In this embodiment, a media file of point cloud media is obtained. The media file includes the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream. According to the cross-attribute dependency indication information, the point cloud bitstream is decoded to present the point cloud media, thereby guiding the transmission, decoding and presentation of the point cloud media, supporting partial transmission and partial decoding at the decoding end, thereby optimizing the utilization of network bandwidth and computing resources at the decoding end.

[0367] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of a point cloud media data processing device provided in an embodiment of this application. The point cloud media data processing device can be installed in the computer equipment provided in the embodiment of this application. The computer equipment can be the content production equipment mentioned in the above method embodiment. Figure 6 The data processing device for point cloud media shown can be a computer program (including program code) running on a computer device, and the data processing device for point cloud media can be used to execute... Figure 4 Some or all of the steps in the method embodiments shown. Please refer to [link / reference]. Figure 6 The data processing device for the point cloud media may include the following units:

[0368] Acquisition unit 601 is used to acquire point cloud media;

[0369] Processing unit 602 is used to encode point cloud media to obtain point cloud bitstream;

[0370] The processing unit 602 is also used to generate cross-attribute dependency indication information based on the encoding and decoding dependency relationship between attribute data in the point cloud code stream;

[0371] The processing unit 602 is also used to encapsulate the cross-attribute dependency indication information and the point cloud code stream to obtain the media file of the point cloud media.

[0372] In one embodiment, when processing unit 602 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0373] The point cloud stream is encapsulated into a track, which contains one or more samples, and each sample corresponds to a point cloud frame in the point cloud media.

[0374] If the cross-attribute dependency indication information indicates that the encoding and decoding dependencies between attribute data in the point cloud bitstream are consistent across all samples of the track, then the cross-attribute dependency indication information is set in the sample entry of the track to form a media file of the point cloud media.

[0375] In one embodiment, when processing unit 602 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0376] The point cloud stream is encapsulated into a track, which contains one or more samples, and each sample corresponds to a point cloud frame in the point cloud media.

[0377] Divide the track into cross-attribute dependent sample groups. Each cross-attribute dependent sample group contains one or more samples. Each sample in the cross-attribute dependent sample group contains or corresponds to the dependent attribute data; or, each sample in the cross-attribute dependent sample group contains or corresponds to the dependent attribute data.

[0378] If the cross-attribute dependency indication information indicates that the encoding and decoding dependencies between attribute data in the point cloud bitstream change across all samples of the track, then the cross-attribute dependency indication information is set in the entry of the cross-attribute dependency sample group to form a media file of the point cloud media.

[0379] In one embodiment, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in a point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data.

[0380] The "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbit, or the "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current sample; the "Identifier of Dependent Attribute Data" field indicates the identifier of the dependent attribute data; the "Number of Dependent Attribute Data" field indicates the number of sets of other attribute data that depend on the current attribute data; the "Identifier of Dependent Attribute Data" field indicates the identifier of other attribute data that depend on the current attribute data.

[0381] Here, the current track refers to the track being encoded in the media file, the current sample refers to the sample being encoded in the current track, and the current attribute data refers to the attribute data being encoded in the current sample.

[0382] In one embodiment, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two sets of attribute data in the point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which includes a field for the number of dependent attribute data, a field for the identifier of dependent attribute data, and a field for the identifier of dependent attribute data.

[0383] The "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbit, or the "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current sample; the "Dependent Attribute Data Identifier" field indicates the identifier of the dependent attribute data in any two sets of attribute data; the "Dependent Attribute Data Identifier" field indicates the identifier of the dependent attribute data in any two sets of attribute data.

[0384] Here, the current track refers to the track being encoded in the media file, and the current sample refers to the sample being encoded in the current track.

[0385] In one embodiment, the point cloud code stream contains only attribute data of the first type and attribute data of the second type; cross-attribute dependency indication information is used to indicate the encoding / decoding dependency relationship between the attribute data of the first type and the attribute data of the second type; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains the data type field of the dependent attribute; when the processing unit 602 generates cross-attribute dependency indication information based on the encoding / decoding dependency relationship between the attribute data in the point cloud code stream, it can be specifically used for:

[0386] If attribute data of the first type is dependent on attribute data of the second type, then the data type field of the dependent attribute will be set to the first value.

[0387] If the attribute data of the second type is dependent on the attribute data of the first type, then the data type field of the dependent attribute will be set to the second value.

[0388] In one embodiment, when processing unit 602 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0389] The point cloud code stream is encapsulated to obtain one or more attribute component tracks; attribute data with encoding and decoding dependencies in the point cloud code stream are located in different attribute component tracks;

[0390] Track groups are used to represent the relationships between different attribute component tracks, forming a media file for point cloud media.

[0391] In one embodiment, the media file includes a track group type data box, which is used to indicate the attribute component track to which attribute data with encoding / decoding dependencies in the point cloud bitstream belongs;

[0392] Cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which is set in the track group type data box.

[0393] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud bitstream are located in different attribute component tracks;

[0394] The media file contains a track reference type data box, which includes a track identifier. The track identifier is used to indicate the attribute component track to which the attribute data that is depended upon in the attribute data with encoding and decoding dependencies belongs.

[0395] The track reference type data box is set in the attribute component track to which the attribute data that has encoding / decoding dependencies belongs.

[0396] If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track depends on at least one sample in the attribute component track indicated by the track identifier during encoding; wherein, the current attribute component track refers to the attribute component track being encoded.

[0397] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud bitstream are located on different attribute component tracks; the media file includes a track reference type data box, and the track reference type box includes a track identifier;

[0398] The track identifier is used to indicate the track of the attribute component to which the dependent attribute data in the attribute data with encoding and decoding dependencies belongs; the track reference type data box is set in the track of the attribute component to which the dependent attribute data in the attribute data with encoding and decoding dependencies belongs;

[0399] If the current property component track contains a track identifier, then at least one sample in the current property component track is dependent on at least one sample in the property component track indicated by the track identifier;

[0400] The current property component track refers to the property component track that is being coded.

[0401] In one embodiment, when processing unit 602 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0402] The point cloud stream is encapsulated into a track, which contains one or more samples, and each sample corresponds to a point cloud frame in the point cloud media.

[0403] Each sample is divided into one or more point cloud patches, and each point cloud patch is represented by a subsample.

[0404] Cross-attribute dependency indication information is set in the sub-sample information data box to form a media file for point cloud media.

[0405] In one embodiment, the cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field; when the processing unit 602 sets the cross-attribute dependency indication information in the sub-sample information data box, it can be specifically used for:

[0406] If the current attribute data depends on other attribute data during encoding, the cross-attribute dependency flag field will be set to the first preset value;

[0407] If the current attribute data does not depend on other attribute data during encoding, then the cross-attribute dependency flag field is set to the second preset value;

[0408] The attribute data identifier field is used to indicate the identifier of the current attribute data;

[0409] Here, the current attribute data refers to the attribute data in the subsample being encoded.

[0410] In one embodiment, the media file includes a track containing one or more samples, with each sample corresponding to a point cloud frame in the point cloud media.

[0411] The media file also includes a component information data box, which contains the type of the component in the track; if the component type is attribute data, the component information data box also includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, which refers to the attribute data being decoded.

[0412] In one embodiment, the point cloud media is transmitted using streaming transmission; the processing unit 602 is further configured to:

[0413] Media files for point cloud media are transmitted based on transmission signaling, which includes cross-attribute dependency indication information.

[0414] In one embodiment, the transmission signaling is DASH signaling.

[0415] Cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in DASH signaling or the dependency identifier field in DASH signaling; or...

[0416] The transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the STM signaling.

[0417] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in the DASH signaling;

[0418] When cross-attribute dependency information descriptors exist in the adaptive set hierarchy, they are used to describe all representations in the adaptive set hierarchy;

[0419] When a cross-attribute dependency information descriptor exists in a representation hierarchy, the cross-attribute dependency information descriptor is used to describe the representation in the corresponding representation hierarchy.

[0420] When a cross-attribute dependency information descriptor exists in a preselected level, the cross-attribute dependency information descriptor is used to describe the point cloud media corresponding to the preselected level.

[0421] In one embodiment, the cross-attribute dependency information descriptor includes at least one of the following elements: the dependent attribute data identifier element, the dependent attribute data type element, the dependent attribute data identifier element, and the dependent attribute data type element;

[0422] The dependent attribute data identifier element is used to indicate the identifier of the attribute data that is depended upon; the dependent attribute data type element is used to indicate the type of the attribute data that is depended upon; the dependent attribute data identifier element is used to indicate the identifier of other attribute data that depends on the current attribute data; the dependent attribute data type element is used to indicate the type of other attribute data that depends on the current attribute data.

[0423] The current attribute data refers to the attribute data that is being encoded.

[0424] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the dependency identifier field in the DASH signaling;

[0425] In attribute data with encoding / decoding dependencies, the dependency identifier field is set in the representation corresponding to the dependent attribute data. The dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data.

[0426] In one embodiment, the transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the SMT signaling;

[0427] In attribute data with encoding / decoding dependencies, the asset group descriptor is set in the asset corresponding to the dependent attribute data. The asset group descriptor includes a dependency flag, a dependency quantity field, and an asset identifier field.

[0428] The dependency flag is set to the first preset value; the dependency quantity field is used to indicate the number of other attribute data sets that the dependent attribute data needs to depend on during decoding; the asset identifier field is used to indicate the asset identifier corresponding to the dependent attribute data.

[0429] In this embodiment, point cloud media is acquired and encoded to obtain a point cloud bitstream; cross-attribute dependency indication information is generated based on the encoding / decoding dependency relationship between attribute data in the point cloud bitstream; the cross-attribute dependency indication information and the point cloud bitstream are encapsulated to obtain a media file of the point cloud media; by generating the cross-attribute dependency indication information, it is convenient to guide the decoding of the point cloud bitstream.

[0430] Furthermore, this application also provides a schematic diagram of the structure of a computer device, which can be found in [reference needed]. Figure 7 The computer device may be the aforementioned media processing device or content production device; the computer device may include: a processor 701, an input device 702, an output device 703, and a memory 704. The processor 701, input device 702, output device 703, and memory 704 are connected via a bus. The memory 704 is used to store computer programs, which include program instructions, and the processor 701 is used to execute the program instructions stored in the memory 704.

[0431] When the computer device is the aforementioned media processing device, in this embodiment of the application, the processor 701 performs the following operations by running the executable program code in the memory 704:

[0432] Obtain the media file of the point cloud media, the media file including the point cloud bitstream of the point cloud media and cross-attribute dependency indication information, the cross-attribute dependency indication information being used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream;

[0433] The point cloud stream is decoded according to the cross-attribute dependency indication information to present the point cloud media.

[0434] In one embodiment, the media file includes a track containing one or more samples, each sample corresponding to a point cloud frame in the point cloud media;

[0435] The cross-attribute dependency indication information is set in the sample entry of the track, and the cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependency between attribute data in the point cloud code stream remains consistent in all samples of the track.

[0436] In one embodiment, the media file includes a track containing a cross-attribute dependent sample group, the cross-attribute dependent sample group containing one or more samples, each sample corresponding to a point cloud frame in the point cloud media; any sample in the cross-attribute dependent sample group contains or corresponds to dependent attribute data; or, any sample in the cross-attribute dependent sample group contains or corresponds to dependent attribute data.

[0437] The cross-attribute dependency indication information is set in the entry of the cross-attribute dependency sample group. The cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependency relationship between attribute data in the point cloud code stream changes in all samples of the track.

[0438] In one embodiment, the cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in the point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, and the cross-attribute dependency information data box contains at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data.

[0439] The dependent attribute data quantity field is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current orbit, or the dependent attribute data quantity field is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current sample; the dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data; the dependent attribute data quantity field is used to indicate the number of groups of other attribute data that depend on the current attribute data; the dependent attribute data identifier field is used to indicate the identifier of other attribute data that depend on the current attribute data;

[0440] Wherein, the current track refers to the track being decoded in the media file, the current sample refers to the sample being decoded in the current track, and the current attribute data refers to the attribute data being decoded in the current sample.

[0441] In one embodiment, the cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two sets of attribute data in the point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which includes a dependent attribute data quantity field, a dependent attribute data identifier field, and a dependent attribute data identifier field.

[0442] The dependent attribute data quantity field is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current orbit, or the dependent attribute data quantity field is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current sample; the dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data in any two groups of attribute data; the dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data in any two groups of attribute data.

[0443] The current track refers to the track being decoded in the media file, and the current sample refers to the sample being decoded in the current track.

[0444] In one embodiment, the point cloud code stream contains only attribute data of the first type and attribute data of the second type; the cross-attribute dependency indication information is used to indicate the encoding / decoding dependency relationship between the attribute data of the first type and the attribute data of the second type; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains the attribute data type field of the dependent attribute.

[0445] If the data type field of the dependent attribute is a first value, it means that the attribute data of the first type is dependent on the attribute data of the second type.

[0446] If the data type field of the dependent attribute is a second value, it means that the attribute data of the second type is dependent on the attribute data of the first type.

[0447] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data in the point cloud bitstream that have the encoding / decoding dependency relationship are located in different attribute component tracks;

[0448] The relationships between the different attribute component tracks are represented by track groups.

[0449] In one embodiment, the media file includes a track group type data box, which is used to indicate the attribute component track to which the attribute data with the encoding / decoding dependency in the point cloud bitstream belongs;

[0450] The cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which is set in the track group type data box.

[0451] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data in the point cloud bitstream that have the encoding / decoding dependency relationship are located on different attribute component tracks; the media file includes a track reference type data box, and the track reference type box includes a track identifier;

[0452] The track identifier is used to indicate the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs; the track reference type data box is set in the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs;

[0453] If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track depends on at least one sample in the attribute component track indicated by the track identifier during decoding.

[0454] The current property component track refers to the property component track that is being decoded.

[0455] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data in the point cloud bitstream that have the encoding / decoding dependency relationship are located on different attribute component tracks; the media file includes a track reference type data box, and the track reference type box includes a track identifier;

[0456] The track identifier is used to indicate the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs; the track reference type data box is set in the attribute component track to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs;

[0457] If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track is dependent on at least one sample in the attribute component track indicated by the track identifier;

[0458] The current property component track refers to the property component track that is being decoded.

[0459] In one embodiment, the media file includes a track containing one or more samples, each sample corresponding to a point cloud frame in the point cloud media;

[0460] A sample is divided into one or more point cloud patches, and each point cloud patch is represented by a subsample.

[0461] The cross-attribute dependency indication information is set in the subsample information data box.

[0462] In one embodiment, the cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field;

[0463] If the cross-attribute dependency flag field is a first preset value, it indicates that the current attribute data depends on other attribute data during decoding;

[0464] If the cross-attribute dependency flag field is a second preset value, it indicates that the current attribute data does not depend on other attribute data during decoding;

[0465] The attribute data identifier field is used to indicate the identifier of the current attribute data;

[0466] The current attribute data refers to the attribute data in the subsample being decoded.

[0467] In one embodiment, the media file includes a track containing one or more samples, each sample corresponding to a point cloud frame in the point cloud media;

[0468] The media file also includes a component information data box, which contains the type of the component in the track; if the type of the component is attribute data, the component information data box also includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, and the current attribute data refers to the attribute data being decoded.

[0469] In one embodiment, the point cloud media is transmitted using streaming; when acquiring the media file of the point cloud media, the processor 701 may specifically be used for:

[0470] Obtain the transmission signaling of the point cloud media, wherein the transmission signaling includes the cross-attribute dependency indication information;

[0471] The media file of the point cloud media is obtained according to the transmission signaling.

[0472] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in the DASH signaling;

[0473] When the cross-attribute dependency information descriptor exists in the adaptive set hierarchy, the cross-attribute dependency information descriptor is used to describe all representations in the adaptive set hierarchy;

[0474] When the cross-attribute dependency information descriptor exists in the representation hierarchy, the cross-attribute dependency information descriptor is used to describe the representation in the corresponding representation hierarchy;

[0475] When the cross-attribute dependency information descriptor exists in the preselected level, the cross-attribute dependency information descriptor is used to describe the point cloud media corresponding to the preselected level.

[0476] In one embodiment, the cross-attribute dependency information descriptor includes at least one of the following elements: the dependent attribute data identifier element, the dependent attribute data type element, the dependent attribute data identifier element, and the dependent attribute data type element;

[0477] The dependent attribute data identifier element is used to indicate the identifier of the dependent attribute data; the dependent attribute data type element is used to indicate the type of the dependent attribute data; the dependent attribute data identifier element is used to indicate the identifier of other attribute data that depends on the current attribute data; the dependent attribute data type element is used to indicate the type of other attribute data that depends on the current attribute data.

[0478] The current attribute data refers to the attribute data that is being decoded.

[0479] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the dependency identifier field in the DASH signaling;

[0480] In the attribute data that has the aforementioned encoding / decoding dependency relationship, the dependency identifier field is set in the representation corresponding to the dependent attribute data, and the dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data.

[0481] In one embodiment, the transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the SMT signaling;

[0482] In the attribute data that has the aforementioned encoding and decoding dependency relationship, the asset group descriptor is set in the asset corresponding to the dependent attribute data, and the asset group descriptor includes a dependency flag, a dependency quantity field, and an asset identifier field;

[0483] The dependency flag is set to a first preset value; the dependency quantity field is used to indicate the number of other attribute data sets that the dependent attribute data needs to depend on during decoding; the asset identifier field is used to indicate the asset identifier corresponding to the dependent attribute data.

[0484] In one embodiment, when the processor 701 decodes the point cloud code stream according to the cross-attribute dependency indication information, it may specifically be used to:

[0485] Based on the encoding / decoding dependency relationship indicated by the cross-attribute dependency indication information, determine the attribute data that the current attribute data depends on;

[0486] Decode the attribute data that the current attribute data depends on;

[0487] After decoding the attribute data on which the current attribute data depends, the current attribute data is then decoded.

[0488] In this embodiment, a media file of point cloud media is obtained. The media file includes the point cloud bitstream of the point cloud media and cross-attribute dependency indication information. The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between attribute data in the point cloud bitstream. According to the cross-attribute dependency indication information, the point cloud bitstream is decoded to present the point cloud media, thereby guiding the transmission, decoding and presentation of the point cloud media, supporting partial transmission and partial decoding at the decoding end, thereby optimizing the utilization of network bandwidth and computing resources at the decoding end.

[0489] Optionally, when the computer device is used to create the above-mentioned content, in this embodiment of the application, the processor 701 performs the following operations by running the executable program code in the memory 704:

[0490] Acquire point cloud media and encode the point cloud media to obtain point cloud bitstream;

[0491] Based on the encoding and decoding dependencies between attribute data in the point cloud code stream, cross-attribute dependency indication information is generated;

[0492] The cross-attribute dependency indication information and point cloud code stream are encapsulated to obtain the media file of the point cloud media.

[0493] In one embodiment, when the processor 701 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0494] The point cloud stream is encapsulated into a track, which contains one or more samples, and each sample corresponds to a point cloud frame in the point cloud media.

[0495] If the cross-attribute dependency indication information indicates that the encoding and decoding dependencies between attribute data in the point cloud bitstream are consistent across all samples of the track, then the cross-attribute dependency indication information is set in the sample entry of the track to form a media file of the point cloud media.

[0496] In one embodiment, when the processor 701 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0497] The point cloud stream is encapsulated into a track, which contains one or more samples, and each sample corresponds to a point cloud frame in the point cloud media.

[0498] Divide the track into cross-attribute dependent sample groups. Each cross-attribute dependent sample group contains one or more samples. Each sample in the cross-attribute dependent sample group contains or corresponds to the dependent attribute data. Alternatively, each sample in the cross-attribute dependent sample group contains or corresponds to the dependent attribute data.

[0499] If the cross-attribute dependency indication information indicates that the encoding and decoding dependencies between attribute data in the point cloud bitstream change across all samples of the track, then the cross-attribute dependency indication information is set in the entry of the cross-attribute dependency sample group to form a media file of the point cloud media.

[0500] In one embodiment, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in a point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data.

[0501] The "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbit; or, the "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current sample; the "Identifier of Dependent Attribute Data" field indicates the identifier of the dependent attribute data; the "Number of Dependent Attribute Data" field indicates the number of sets of other attribute data that depend on the current attribute data; the "Identifier of Dependent Attribute Data" field indicates the identifier of other attribute data that depend on the current attribute data.

[0502] Here, the current track refers to the track being encoded in the media file, the current sample refers to the sample being encoded in the current track, and the current attribute data refers to the attribute data being encoded in the current sample.

[0503] In one embodiment, cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two sets of attribute data in the point cloud code stream; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which includes a field for the number of dependent attribute data, a field for the identifier of dependent attribute data, and a field for the identifier of dependent attribute data.

[0504] The "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current orbit; or, the "Number of Dependent Attribute Data" field indicates the number of sets of dependent attribute data contained in or corresponding to the current sample; the "Dependent Attribute Data Identifier" field indicates the identifier of the dependent attribute data in any two sets of attribute data; the "Dependent Attribute Data Identifier" field indicates the identifier of the dependent attribute data in any two sets of attribute data.

[0505] Here, the current track refers to the track being encoded in the media file, and the current sample refers to the sample being encoded in the current track.

[0506] In one embodiment, the point cloud code stream contains only attribute data of the first type and attribute data of the second type; cross-attribute dependency indication information is used to indicate the encoding / decoding dependency relationship between the attribute data of the first type and the attribute data of the second type; the cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains the data type field of the dependent attribute; when the processor 701 generates cross-attribute dependency indication information based on the encoding / decoding dependency relationship between the attribute data in the point cloud code stream, it can be specifically used for:

[0507] If attribute data of the first type is dependent on attribute data of the second type, then the data type field of the dependent attribute will be set to the first value.

[0508] If the attribute data of the second type is dependent on the attribute data of the first type, then the data type field of the dependent attribute will be set to the second value.

[0509] In one embodiment, when the processor 701 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0510] The point cloud code stream is encapsulated to obtain one or more attribute component tracks; attribute data with encoding and decoding dependencies in the point cloud code stream are located in different attribute component tracks;

[0511] Track groups are used to represent the relationships between different attribute component tracks, forming a media file for point cloud media.

[0512] In one embodiment, the media file includes a track group type data box, which is used to indicate the attribute component track to which attribute data with encoding / decoding dependencies in the point cloud bitstream belongs;

[0513] Cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which is set in the track group type data box.

[0514] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud bitstream are located in different attribute component tracks;

[0515] The media file contains a track reference type data box, which includes a track identifier. The track identifier is used to indicate the attribute component track to which the attribute data that is depended upon in the attribute data with encoding and decoding dependencies belongs.

[0516] The track reference type data box is set in the attribute component track to which the attribute data that has encoding and decoding dependencies belongs;

[0517] If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track depends on at least one sample in the attribute component track indicated by the track identifier during encoding; wherein, the current attribute component track refers to the attribute component track being encoded.

[0518] In one embodiment, the media file includes one or more attribute component tracks, and the attribute data with encoding / decoding dependencies in the point cloud bitstream are located in different attribute component tracks;

[0519] The media file contains a track reference type data box, which includes a track identifier. The track identifier is used to indicate the track of the attribute component to which the attribute data that the attribute data depends on has encoding and decoding dependencies belongs.

[0520] The track reference type data box is set in the attribute component track to which the attribute data that is depended upon belongs, within the attribute data that has encoding and decoding dependencies;

[0521] If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track is relied upon by at least one sample in the attribute component track indicated by the track identifier during encoding; wherein, the current attribute component track refers to the attribute component track being encoded.

[0522] In one embodiment, when the processor 701 encapsulates cross-attribute dependency indication information and point cloud bitstream to obtain a media file of point cloud media, it can specifically be used for:

[0523] The point cloud stream is encapsulated into a track, which contains one or more samples, and each sample corresponds to a point cloud frame in the point cloud media.

[0524] Each sample is divided into one or more point cloud patches, and each point cloud patch is represented by a subsample.

[0525] Cross-attribute dependency indication information is set in the sub-sample information data box to form a media file for point cloud media.

[0526] In one embodiment, the cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field; when the processor 701 sets the cross-attribute dependency indication information in the sub-sample information data box, it can specifically be used for:

[0527] If the current attribute data depends on other attribute data during encoding, the cross-attribute dependency flag field will be set to the first preset value;

[0528] If the current attribute data does not depend on other attribute data during decoding, then the cross-attribute dependency flag field is set to the second preset value;

[0529] The attribute data identifier field is used to indicate the identifier of the current attribute data; the current attribute data refers to the attribute data in the subsample being encoded.

[0530] In one embodiment, the media file includes a track containing one or more samples, with each sample corresponding to a point cloud frame in the point cloud media.

[0531] The media file also includes a component information data box, which contains the type of the component in the track; if the component type is attribute data, the component information data box also includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, which refers to the attribute data being decoded.

[0532] In one embodiment, the point cloud media is transmitted using streaming; the processor 701 is also used for:

[0533] Media files for point cloud media are transmitted based on transmission signaling, which includes cross-attribute dependency indication information.

[0534] In one embodiment, the transmission signaling is DASH signaling.

[0535] Cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in DASH signaling or the dependency identifier field in DASH signaling; or...

[0536] The transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the STM signaling.

[0537] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in the DASH signaling;

[0538] When cross-attribute dependency information descriptors exist in the adaptive set hierarchy, they are used to describe all representations in the adaptive set hierarchy;

[0539] When a cross-attribute dependency information descriptor exists in a representation hierarchy, the cross-attribute dependency information descriptor is used to describe the representation in the corresponding representation hierarchy.

[0540] When a cross-attribute dependency information descriptor exists in a preselected level, the cross-attribute dependency information descriptor is used to describe the point cloud media corresponding to the preselected level.

[0541] In one embodiment, the cross-attribute dependency information descriptor includes at least one of the following elements: the dependent attribute data identifier element, the dependent attribute data type element, the dependent attribute data identifier element, and the dependent attribute data type element;

[0542] The dependent attribute data identifier element is used to indicate the identifier of the attribute data that is depended upon; the dependent attribute data type element is used to indicate the type of the attribute data that is depended upon; the dependent attribute data identifier element is used to indicate the identifier of other attribute data that depends on the current attribute data; the dependent attribute data type element is used to indicate the type of other attribute data that depends on the current attribute data.

[0543] The current attribute data refers to the attribute data that is being encoded.

[0544] In one embodiment, the transmission signaling is DASH signaling, and the cross-attribute dependency indication information refers to the dependency identifier field in the DASH signaling;

[0545] In attribute data with encoding / decoding dependencies, the dependency identifier field is set in the representation corresponding to the dependent attribute data. The dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data.

[0546] In one embodiment, the transmission signaling is SMT signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the SMT signaling;

[0547] In attribute data with encoding / decoding dependencies, the asset group descriptor is set in the asset corresponding to the dependent attribute data. The asset group descriptor includes a dependency flag, a dependency quantity field, and an asset identifier field.

[0548] The dependency flag is set to the first preset value; the dependency quantity field is used to indicate the number of other attribute data sets that the dependent attribute data needs to depend on during decoding; the asset identifier field is used to indicate the asset identifier corresponding to the dependent attribute data.

[0549] In this embodiment, point cloud media is acquired and encoded to obtain a point cloud bitstream; cross-attribute dependency indication information is generated based on the encoding / decoding dependency relationship between attribute data in the point cloud bitstream; the cross-attribute dependency indication information and the point cloud bitstream are encapsulated to obtain a media file of the point cloud media; by generating the cross-attribute dependency indication information, it is convenient to guide the decoding of the point cloud bitstream.

[0550] Furthermore, it should be noted that this application also provides a computer-readable storage medium storing a computer program, which includes program instructions. When a processor executes these program instructions, it can execute the aforementioned... Figure 3 andFigure 4 The methods described in the corresponding embodiments are therefore not repeated here. For technical details not disclosed in the computer-readable storage medium embodiments related to this application, please refer to the description of the method embodiments of this application. As an example, program instructions may be deployed on a computer device, executed on multiple computer devices located in one location, or executed on multiple computer devices distributed in multiple locations and interconnected through a communication network.

[0551] According to one aspect of this application, a computer program product is provided, comprising a computer program stored in a computer-readable storage medium. A processor of a computer device reads the computer program from the computer-readable storage medium, and the processor executes the computer program, enabling the computer device to perform the aforementioned... Figure 3 and Figure 4 The methods described in the corresponding embodiments will not be repeated here.

[0552] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0553] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments and making equivalent changes in accordance with the claims of this application are still within the scope of the invention.

Claims

1. A data processing method for point cloud media, characterized in that, include: A media file of point cloud media is obtained, the media file including the point cloud bitstream of the point cloud media and cross-attribute dependency indication information, the cross-attribute dependency indication information being used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in the point cloud bitstream; the media file includes a track, the track containing a cross-attribute dependency sample group, the cross-attribute dependency sample group containing one or more samples, each sample in the cross-attribute dependency sample group corresponding to a point cloud frame in the point cloud media; any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data; or, any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data. According to the cross-attribute dependency indication information, the point cloud code stream is decoded to present the point cloud media; The cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data.

2. The method as described in claim 1, characterized in that, The points in the point cloud media include one or more sets of attribute data, each set of attribute data being used to represent an attribute possessed by the point; the attribute includes at least one of the following: color, reflectivity, and material; The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in the point cloud code stream.

3. The method as described in claim 1, characterized in that, The track contains one or more samples, and each sample in the track corresponds to a point cloud frame in the point cloud media; The cross-attribute dependency indication information is set in the sample entry of the track. The cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependency relationship between attribute data in the point cloud code stream does not change in all samples of the track.

4. The method as described in claim 1, characterized in that, The cross-attribute dependency indication information is set in the entry of the cross-attribute dependency sample group. The cross-attribute dependency indication information is also used to indicate that the encoding and decoding dependency relationship between attribute data in the point cloud code stream changes in all samples of the track.

5. The method according to any one of claims 1-4, characterized in that, The number of dependent attribute data fields is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current orbit, or the number of dependent attribute data fields is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current sample. The dependent attribute data identifier field is used to indicate the identifier of the attribute data that is depended upon; the dependent attribute data quantity field is used to indicate the number of other attribute data groups that depend on the current attribute data; The dependent attribute data identifier field is used to indicate the identifiers of other attribute data that depend on the current attribute data; Wherein, the current track refers to the track being decoded in the media file, the current sample refers to the sample being decoded in the current track, and the current attribute data refers to the attribute data being decoded in the current sample.

6. The method according to any one of claims 1-4, characterized in that, The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between any two sets of attribute data in the point cloud code stream; The number of dependent attribute data fields is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current orbit, or the number of dependent attribute data fields is used to indicate the number of groups of dependent attribute data contained in or corresponding to the current sample. The dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data in any two sets of attribute data; the dependent attribute data identifier field is used to indicate the identifier of the dependent attribute data in any two sets of attribute data. The current track refers to the track in the media file that is being decoded, and the current sample refers to the sample in the current track that is being decoded.

7. The method according to any one of claims 1-4, characterized in that, The point cloud code stream contains only attribute data of the first type and attribute data of the second type; the cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between the attribute data of the first type and the attribute data of the second type; the cross-attribute dependency information data box also contains the attribute data type field of the dependent attribute. If the data type field of the dependent attribute is a first value, it means that the attribute data of the first type is dependent on the attribute data of the second type. If the data type field of the dependent attribute is a second value, it means that the attribute data of the second type is dependent on the attribute data of the first type.

8. The method according to any one of claims 1-4, characterized in that, The media file includes one or more attribute component tracks, and the attribute data with the encoding / decoding dependency in the point cloud bitstream are located in different attribute component tracks; The relationships between the different attribute component tracks are represented by track groups.

9. The method as described in claim 8, characterized in that, The media file contains a track group type data box, which is used to indicate the attribute component track to which the attribute data with the encoding and decoding dependency in the point cloud bitstream belongs; The cross-attribute dependency information data box is set in the track group type data box.

10. The method as described in claim 1, characterized in that, The media file includes one or more attribute component tracks, and the attribute data with the encoding / decoding dependency in the point cloud bitstream are located on different attribute component tracks; the media file contains a track reference type data box, and the track reference type box includes a track identifier; The track identifier is used to indicate the track of the attribute component to which the dependent attribute data in the attribute data with the encoding / decoding dependency relationship belongs; The track reference type data box is set in the attribute component track to which the attribute data that has the encoding and decoding dependency relationship belongs; If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track depends on at least one sample in the attribute component track indicated by the track identifier during decoding. The current property component track refers to the property component track that is being decoded.

11. The method as described in claim 1, characterized in that, The media file includes one or more attribute component tracks, and the attribute data with the encoding / decoding dependency in the point cloud bitstream are located on different attribute component tracks; the media file contains a track reference type data box, and the track reference type box includes a track identifier; The track identifier is used to indicate the track of the attribute component to which the attribute data that depends on the attribute data in the attribute data with the encoding and decoding dependency relationship belongs; The track reference type data box is set in the attribute component track to which the attribute data that is depended upon in the attribute data that has the encoding and decoding dependency relationship belongs; If the current attribute component track contains a track identifier, then at least one sample in the current attribute component track is dependent on at least one sample in the attribute component track indicated by the track identifier; The current property component track refers to the property component track that is being decoded.

12. The method as described in claim 1, characterized in that, The track contains one or more samples, and each sample in the track corresponds to a point cloud frame in the point cloud media; A sample in the orbit is divided into one or more point cloud patches, and each point cloud patch is represented by a subsample. The cross-attribute dependency indication information is set in the subsample information data box.

13. The method as described in claim 12, characterized in that, The cross-attribute dependency indication information includes a cross-attribute dependency flag field and an attribute data identifier field; If the cross-attribute dependency flag field is a first preset value, it indicates that the current attribute data depends on other attribute data during decoding; If the cross-attribute dependency flag field is a second preset value, it indicates that the current attribute data does not depend on other attribute data during decoding; The attribute data identifier field is used to indicate the identifier of the current attribute data; The current attribute data refers to the attribute data in the subsample being decoded.

14. The method as described in claim 1, characterized in that, The track contains one or more samples, and each sample in the track corresponds to a point cloud frame in the point cloud media; The media file also includes a component information data box, which contains the type of the component in the track; if the type of the component is attribute data, the component information data box also includes an attribute identifier field, which is used to indicate the identifier of the current attribute data, and the current attribute data refers to the attribute data being decoded.

15. The method as described in claim 1, characterized in that, The point cloud media is transmitted using streaming; the acquisition of the media file for the point cloud media includes: Obtain the transmission signaling of the point cloud media, wherein the transmission signaling includes the cross-attribute dependency indication information; The media file of the point cloud media is obtained according to the transmission signaling.

16. The method as described in claim 15, characterized in that, The transmission signaling is dynamic adaptive flow signaling, and the cross-attribute dependency indication information refers to the cross-attribute dependency information descriptor in the dynamic adaptive flow signaling. When the cross-attribute dependency information descriptor exists in the adaptive set hierarchy, the cross-attribute dependency information descriptor is used to describe all representations in the adaptive set hierarchy; When the cross-attribute dependency information descriptor exists in the representation hierarchy, the cross-attribute dependency information descriptor is used to describe the representation in the corresponding representation hierarchy; When the cross-attribute dependency information descriptor exists in the preselected level, the cross-attribute dependency information descriptor is used to describe the point cloud media corresponding to the preselected level.

17. The method as described in claim 16, characterized in that, The cross-attribute dependency information descriptor includes at least one of the following elements: the dependent attribute data identifier element, the dependent attribute data type element, the dependent attribute data identifier element, and the dependent attribute data type element; The dependent attribute data identifier element is used to indicate the identifier of the dependent attribute data; the dependent attribute data type element is used to indicate the type of the dependent attribute data. The dependent attribute data identifier element is used to indicate the identifier of other attribute data that depends on the current attribute data; the dependent attribute data type element is used to indicate the type of other attribute data that depends on the current attribute data. The current attribute data refers to the attribute data that is being decoded.

18. The method as described in claim 15, characterized in that, The transmission signaling is dynamic adaptive flow signaling, and the cross-attribute dependency indication information refers to the dependency identifier field in the dynamic adaptive flow signaling; In the attribute data that has the aforementioned encoding / decoding dependency relationship, the dependency identifier field is set in the representation corresponding to the dependent attribute data, and the dependency identifier field is used to indicate the identifier of the representation corresponding to the dependent attribute data.

19. The method as described in claim 15, characterized in that, The transmission signaling is intelligent media transmission signaling, and the cross-attribute dependency indication information refers to the asset group descriptor in the intelligent media transmission signaling; In the attribute data that has the aforementioned encoding and decoding dependency relationship, the asset group descriptor is set in the asset corresponding to the dependent attribute data, and the asset group descriptor includes a dependency flag, a dependency quantity field, and an asset identifier field; The dependency flag is set to a first preset value; The dependency quantity field is used to indicate the number of other attribute data sets that the dependent attribute data needs to depend on during decoding; the asset identifier field is used to indicate the asset identifier corresponding to the dependent attribute data.

20. The method as described in claim 1, characterized in that, Decoding the point cloud code stream according to the cross-attribute dependency indication information includes: Based on the encoding / decoding dependency relationship indicated by the cross-attribute dependency indication information, determine the attribute data that the current attribute data depends on; Decode the attribute data that the current attribute data depends on; After decoding the attribute data on which the current attribute data depends, the current attribute data is then decoded.

21. A data processing method for point cloud media, characterized in that, include: Acquire point cloud media and encode the point cloud media to obtain point cloud bitstream; Based on the encoding and decoding dependencies between attribute data in the point cloud code stream, cross-attribute dependency indication information is generated; The cross-attribute dependency indication information is used to indicate the encoding and decoding dependency relationship between two or more sets of attribute data in the point cloud code stream; The cross-attribute dependency indication information and the point cloud bitstream are encapsulated to obtain a media file of the point cloud media; the media file includes a track, the track contains a cross-attribute dependency sample group, the cross-attribute dependency sample group contains one or more samples, and each sample in the cross-attribute dependency sample group corresponds to a point cloud frame in the point cloud media; any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data; or, any sample in the cross-attribute dependency sample group contains or corresponds to the dependent attribute data. The cross-attribute dependency indication information is represented as a cross-attribute dependency information data box, which contains at least one of the following fields: the number of dependent attribute data, the identifier of dependent attribute data, the number of dependent attribute data, and the identifier of dependent attribute data.

22. A computer device, characterized in that, include: A processor is used to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, performs the data processing method for point cloud media as described in any one of claims 1-21.

23. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, performs the data processing method for point cloud media as described in any one of claims 1-21.

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