WO2024234159A1 - Point cloud coding method, point cloud decoding method, decoder, coder, and computer-readable storage medium - Google Patents

Abstract

Provided are a point cloud coding method, a point cloud decoding method, a decoder, a coder, and a computer-readable storage medium, which can improve the coding and decoding efficiency, thereby improving the coding and decoding performance. The decoding method comprises: parsing a code stream, so as to determine a prediction tree corresponding to a point cloud and a prediction index corresponding to the current node (S101); on the basis of the number of child nodes of a parent node of the current node in the prediction tree, determining the current prediction list corresponding to the current node (S102); and on the basis of the prediction index and the current prediction list, determining an intra-frame prediction value corresponding to the current node (S103).

Description

Point cloud encoding and decoding method, decoder, encoder and computer readable storage medium Technical Field

The embodiments of the present application relate to point cloud encoding and decoding technology, and relate to but are not limited to a point cloud encoding and decoding method, a decoder, an encoder, and a computer-readable storage medium.

Background Art

In the azimuth-based geometric prediction coding scheme of point cloud coding, the value of the first pair of radius and azimuth in the prediction list needs to be determined based on the radius and azimuth of the previous encoded node of the current node to be encoded. Due to the encoding order of multiple laser beams in the point cloud, when encoding the second node on the current laser beam, its previous encoded node is the last node on the previous encoded laser beam. In other words, it is necessary to wait until the encoding of the node on the previous laser beam is completed before the second node and subsequent nodes on the current laser beam can be encoded. The same is true on the decoding side. This means that for the point on the last encoded and decoded laser beam, there is a time delay of nearly one frame of point cloud between it and the point on the first encoded and decoded laser beam, which is not conducive to real-time encoding and decoding, thereby increasing the encoding and decoding time and reducing the encoding and decoding performance.

Summary of the invention

The embodiments of the present application provide a point cloud encoding and decoding method, a decoder, an encoder, and a computer-readable storage medium, which can improve the encoding and decoding efficiency and thus improve the encoding and decoding performance.

The technical solution of this application is implemented as follows:

The present application provides a decoding method, including:

Parse the bitstream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node;

Determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree;

Based on the prediction index and the current prediction list, an intra-frame prediction value corresponding to the current node is determined.

The present application provides an encoding method, including:

Determine the prediction tree corresponding to the point cloud;

Determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree;

Predicting the current node based on the current prediction list, and determining at least one intra-frame prediction value corresponding to the current node;

Based on the at least one intra-frame prediction value, determine the geometric information encoding corresponding to the current node.

The present application provides a decoding method, including:

Parse the bitstream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node;

Determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree;

Based on the prediction index and the current prediction list, an intra-frame prediction value corresponding to the current node is determined.

The present application provides an encoding method, including:

Determine the prediction tree corresponding to the point cloud;

Determine a current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree;

Predicting the current node based on the current prediction list, and determining at least one intra-frame prediction value corresponding to the current node;

Based on the at least one intra-frame prediction value, determine the geometric information encoding corresponding to the current node.

The present application provides a decoder, including:

A first parsing part is configured to parse the bitstream to determine a prediction tree corresponding to the point cloud and a prediction index corresponding to the current node;

A first determining part is configured to determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree;

The first prediction part is configured to determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list.

The present application provides an encoder, including:

A first construction part is configured to determine a prediction tree corresponding to the point cloud;

A second determining part is configured to determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree;

A second prediction part is configured to predict the current node based on the current prediction list and determine at least one intra-frame prediction value corresponding to the current node;

The first encoding part is configured to determine the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value.

The present application provides a decoder, including:

The second parsing part is configured to parse the code stream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node;

A third determining part is configured to determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree;

The third prediction part is configured to determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list.

The present application provides an encoder, including:

A second construction part is configured to determine a prediction tree corresponding to the point cloud;

A fourth determining part is configured to determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree;

A fourth prediction part is configured to predict the current node based on the current prediction list and determine at least one intra-frame prediction value corresponding to the current node;

The second encoding part is configured to determine the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value.

The present application provides a decoder, including:

a first memory and a first processor;

The first memory stores a computer program that can be run on the first processor, and when the first processor executes the program, the decoding method provided in the embodiment of the present application is implemented.

The present application provides an encoder, including:

a second memory and a second processor;

The second memory stores a computer program that can be run on the second processor, and when the second processor executes the program, the encoding method provided in the embodiment of the present application is implemented.

An embodiment of the present application provides a code stream, which is generated by bit encoding based on information to be encoded; wherein the information to be encoded includes geometric information encoding corresponding to a current node in a point cloud; the geometric information encoding is determined based on at least one intra-frame prediction value; the at least one intra-frame prediction value is determined by predicting the current node based on the current prediction list; the current prediction list is determined based on the number of child nodes of the parent node of the current node in the prediction tree.

An embodiment of the present application provides a code stream, which is generated by bit encoding based on information to be encoded; wherein the information to be encoded includes geometric information encoding corresponding to a current node in a point cloud; the geometric information encoding is determined based on at least one intra-frame prediction value; the at least one intra-frame prediction value is determined by predicting the current node based on the current prediction list; the current prediction list is determined based on the position of the parent node of the current node in the prediction tree.

An embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a first processor, the decoding method provided by the embodiment of the present application is implemented; or, when the computer program is executed by a second processor, the encoding method provided by the embodiment of the present application is implemented.

The embodiment of the present application provides a point cloud encoding and decoding method, a decoder, an encoder, and a computer-readable storage medium. When decoding the current node, the current prediction list corresponding to the current node is determined according to the number of child nodes of the parent node of the current node in the prediction tree, and then the intra-frame prediction value corresponding to the current node is determined based on the prediction index of the current node parsed in the code stream and the current prediction list. Thus, each laser beam in the point cloud can be decoded independently, and the decoding between different laser beams does not affect each other and can be executed in parallel, thereby reducing the decoding delay, improving the decoding efficiency, and thus improving the decoding performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of G-PCC geometric coding;

FIG2 is a schematic diagram of an optional structure of a prediction tree provided in an embodiment of the present application;

FIG3 is a flow chart of G-PCC geometric decoding;

FIG4 is a schematic diagram of an optional flow chart of a decoding method provided in an embodiment of the present application;

FIG5 is a schematic diagram of an optional process of updating a prediction list provided in an embodiment of the present application;

FIG6 is a schematic diagram of an optional process of updating a prediction list provided in an embodiment of the present application;

FIG7 is a schematic diagram of an optional flow chart of a decoding method provided in an embodiment of the present application;

FIG8 is a schematic diagram of an optional flow chart of a decoding method provided in an embodiment of the present application;

FIG9 is a schematic diagram of an optional flow chart of an encoding method provided in an embodiment of the present application;

FIG10 is a schematic diagram of an optional flow chart of a decoding method provided in an embodiment of the present application;

FIG11 is a schematic diagram of an optional flow chart of an encoding method provided in an embodiment of the present application;

FIG12 is a schematic diagram of an independent prediction list corresponding to each laser beam in a prediction tree provided in an embodiment of the present application;

FIG13 is a schematic diagram of an optional structure of a decoder provided in an embodiment of the present application;

FIG14 is a schematic diagram of an optional structure of an encoder provided in an embodiment of the present application;

FIG15 is a schematic diagram of an optional structure of a decoder provided in an embodiment of the present application;

FIG16 is a schematic diagram of an optional structure of an encoder provided in an embodiment of the present application;

FIG17 is a schematic diagram of an optional structure of a decoder provided in an embodiment of the present application;

FIG. 18 is a schematic diagram of an optional structure of an encoder provided in an embodiment of the present application.

DETAILED DESCRIPTION

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described here can be implemented in an order other than that illustrated or described here.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

With the improvement of hardware processing power and the rapid development of computer vision, 3D point cloud has become a new generation of immersive multimedia after audio, image and video, and is widely used in applications such as virtual reality, augmented reality, autonomous driving and environmental modeling. However, point cloud usually has a large amount of data, which is not conducive to its transmission and storage, so it is necessary to efficiently encode and decode the point cloud.

Point cloud compression algorithms include two schemes developed by the International Moving Picture Experts Group (MPEG), namely Video-based Point Cloud Compression (V-PCC) and Geometry-based Point Cloud Compression (G-PCC). Among them, the geometry compression in G-PCC is mainly implemented through the octree model and/or the triangle surface model. V-PCC is mainly implemented through 3D to 2D projection and video compression.

In the current azimuth-based geometric prediction encoding (decoding) scheme, except for the 0th laser beam, the first node of each remaining laser beam has the first node of its previous laser beam as the parent node. The encoder (decoder) first encodes (decodes) the head node of each laser beam according to the prediction tree formed by each laser beam in the point cloud, and then encodes and decodes the non-head nodes on each laser beam in a depth-first order. Here, when the encoder (decoder) encodes (decodes) the point on the i-th laser beam and encodes (decodes) the second node on the i-1th laser beam, its previous encoded (decoded) node is the last node on the i-th laser beam. The values of the first pair of radius and azimuth in the prediction list are the radius and azimuth of the previous encoded (decoded) node of the current node to be encoded (decoded). Furthermore, when inter-frame prediction is enabled, the context for encoding interFlag needs to be determined based on the interFlag of the previous five encoded (decoded) points, and the inter-frame prediction point also needs to be found in the reference frame through the previous encoded (decoded) node of the point to be encoded (decoded). In addition, the context information for the symbol encoding (decoding) of the azimuth and radius prediction residuals also needs to be determined based on the previous encoded (decoded) node. Therefore, for the point on the i-1th laser beam, it is necessary to wait until the encoding (decoding) of the point on the i-th laser beam is completed before encoding (decoding) can be performed. This means that for the point on the last encoded (decoded) laser beam, there is a time delay of nearly one frame of point cloud between it and the point on the first encoded (decoded) laser beam, which is not conducive to real-time encoding (decoding), thereby reducing the encoding and decoding efficiency, and further reducing the encoding and decoding performance.

The present invention provides a coding method, a decoder, an encoder and a computer-readable storage medium, which can improve the coding and decoding Efficiency, improve encoding and decoding performance. In order to facilitate the understanding of the technical solution provided in the embodiment of the present application, a flow chart of G-PCC geometric encoding and a flow chart of G-PCC geometric decoding are first provided. It should be noted that the flow chart of G-PCC geometric encoding and the flow chart of G-PCC geometric decoding described in the embodiment of the present application are only for more clearly illustrating the technical solution of the embodiment of the present application, and do not constitute a limitation on the technical solution provided in the embodiment of the present application. Those skilled in the art will know that with the evolution of point cloud compression technology and the emergence of new business scenarios, the technical solution provided in the embodiment of the present application is also applicable to point cloud encoding and decoding architectures similar to G-PCC. The point cloud compressed in the embodiment of the present application can be a point cloud in a video, but is not limited to this.

In the point cloud G-PCC encoder framework, the point cloud of the input 3D image model is sliced and each slice is encoded independently.

The flowchart of G-PCC geometric coding as shown in Figure 1 is applied to the encoder. For the point cloud data to be encoded, the point cloud data is first divided into multiple slices by strip division. In each slice, the geometric information and attribute information of the point cloud are encoded separately. In the geometric coding process, the geometric information is transformed so that all the point clouds are contained in a bounding box, and then quantized. Quantization mainly plays a role in scaling. Due to the quantization rounding, the geometric information of a part of the point cloud is the same. It can be decided whether to remove duplicate points based on parameters. The process of quantization and removal of duplicate points is also called voxelization. At present, the geometric coding of G-PCC can be divided into: octree-based geometric coding and prediction tree-based geometric coding. In the prediction tree-based geometric coding, the input geometric information is first sorted. Common sorting methods include random order, Morton order, azimuth order, and radial distance order. The default sorting method of the current G-PCC standard test conditions is based on azimuth, that is, the points are sorted according to azimuth, radial distance, and pitch angle tangent value. First, the cylindrical coordinates of the input point cloud are calculated based on the Cartesian coordinates (x, y, z) Where r is the radial distance of the point, which can also be called the radius; is the azimuth angle of the point; θ is the elevation angle of the laser beam to which the point belongs. Then according to Sort by r, tanθ. First compare If the size If they are the same, then r is compared. If r is the same, then tanθ is compared, and finally the entire point cloud is reordered. Depending on whether the angle mode is turned on, the prediction tree geometry coding can be divided into an azimuth-based geometry prediction coding scheme and a KD-tree-based geometry prediction coding scheme.

In the azimuth-based geometric prediction coding scheme, when building the prediction tree, the encoder first converts the input point cloud from Cartesian coordinates (x, y, z) to cylindrical coordinates Then each point in the input point cloud is divided into different laser beams according to its pitch angle. Here, the laser beam can also be regarded as a line in the prediction tree. Since the azimuth-based sorting method is used by default when sorting the input geometric information, the geometric information of the entire point cloud is arranged in order from small to large azimuth. In other words, for the i-th laser beam (i-th line), the first point visited is the point with the smallest azimuth among all the points belonging to the laser beam. And the parent node of the points subsequently visited by the i-th beam is the first point in the same laser beam with a smaller azimuth than itself. The parent node of the first point of the i-th laser beam is the first point of the i-1-th laser beam. Among them, i is not less than 1. For the first point of the 0th laser beam, since it has no parent node, it serves as the root node of the entire tree. As shown in Figure 2.

Next, predictive coding is performed on each node in the prediction tree in a depth-first order. First, traverse each node (to be encoded) in the prediction tree starting from the root node, and determine the predicted value of the geometric information of each node according to the intra-frame prediction algorithm or the inter-frame prediction algorithm. In intra-frame prediction, each node is predicted by selecting different prediction values in the prediction list. For inter-frame prediction, the prediction point is found in the previous encoded frame to predict each node. Then, the prediction value with the minimum bit rate is selected as the prediction value of each node through rate-distortion optimization. Then, the prediction residual is obtained by subtracting the true value of the node geometry information from the predicted value, and the prediction residual is quantized using the quantization parameter. Finally, the quantization parameter, the selected prediction value index, the prediction residual and other information are encoded. Through the above process, the code corresponding to each node in the prediction tree is obtained, and a binary code stream, that is, a geometric code stream, is generated.

The flowchart of G-PCC decoding shown in Figure 3 is applied to the decoder. The decoder obtains a binary code stream and decodes the geometric bit stream (i.e., geometric code stream) in the binary code stream. In the prediction tree-based geometric decoding, for each node (point to be decoded) in the prediction tree, first decode the quantization coefficient and prediction index corresponding to each node, and uniquely determine the corresponding prediction value according to the prediction index; then decode the prediction residual of the geometric information, and dequantize it according to the quantization coefficient; then restore the initial geometric reconstruction information of the point to be decoded according to the prediction value and the dequantized prediction residual; then perform an inverse coordinate transformation on the obtained initial reconstructed geometric information to obtain the reconstructed geometric information. Reconstruct the geometric information based on each node to restore the three-dimensional image model of the point cloud data.

It should be noted that the encoding method of the embodiment of the present application is mainly applied to the predictive encoding and arithmetic encoding process in the geometric information encoding process of G-PCC as shown in Figure 1; the decoding method of the embodiment of the present application is mainly applied to the arithmetic decoding and predictive decoding process of the geometric information decoding process of G-PCC as shown in Figure 3. In other words, the embodiment of the present application can be applied to both the encoder and the decoder, and can even be applied to both the encoder and the decoder at the same time, but the embodiment of the present application does not specifically limit this.

It should be noted that the encoding method and decoding method of the embodiments of the present application can also be used in other point cloud encoding and decoding processes besides G-PCC.

It should also be noted that when applied to an encoder, the "current node" specifically refers to the node currently to be encoded in the prediction tree; when applied to a decoder, the "current node" specifically refers to the node currently to be decoded in the prediction tree.

An optional decoding method applied to a decoder provided in an embodiment of the present application is described below.

Refer to Figure 4, which is an optional flowchart of a decoding method provided in an embodiment of the present application, which will be explained in conjunction with the steps shown in Figure 4.

S101, parsing the code stream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node.

In the embodiment of the present application, the decoder parses the bitstream, and obtains the prediction tree corresponding to the point cloud to be decoded and the prediction index corresponding to the current node in the prediction tree from the bitstream. The nodes in the prediction tree are the points in the point cloud, and the prediction tree contains the positional relationship between the nodes. Its structure can be shown in Figure 2, which will not be repeated here.

S102: Determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree.

In the embodiment of the present application, for the current node to be decoded, the parent node of the current node can be determined according to the position relationship of the nodes in the prediction tree. The decoder determines the current prediction list corresponding to the current node based on the number of child nodes of the parent node in the prediction tree.

In some embodiments, when the number of child nodes of the parent node is greater than or equal to the preset child node number threshold, it means that the parent node of the current node is the head node of a laser beam in the prediction tree, and the current node may be the head node of another laser beam, and the current node may also be the second node in the same laser beam as the parent node. The decoder can use the method of initializing the prediction list to determine the preset prediction list as the current prediction list. In this way, the decoding of the current node does not need to wait until the previous laser beam decodes the last node before starting, which can effectively reduce the decoding delay.

In some embodiments, the preset child node number threshold may be set according to the number of child nodes corresponding to the head node in the prediction tree. Exemplarily, the preset child node number threshold may be 2. When the number of child nodes of the current node is equal to 2, the decoder may determine that the preset prediction list is the prediction list corresponding to the current node.

In some embodiments, when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, it indicates that the parent node and the current node belong to the same laser beam, the current node and the parent node are not head nodes, and the previous decoded node of the current node is the parent node. The decoder updates the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous decoded node of the current node, that is, the reconstruction information of the parent node, and determines the current prediction list.

In some embodiments, when the current node does not have a parent node, it indicates that the current node is the root node of the prediction tree. The decoder also determines that the preset prediction list is the current prediction list.

S103: Determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list.

In the embodiment of the present application, the prediction index corresponds to a unique prediction value in at least one pair of prediction values in the current prediction list. The decoder can determine the intra-frame prediction value corresponding to the current node based on the prediction value corresponding to the prediction index in the current prediction list.

In some embodiments, when the number of child nodes of the parent node is greater than or equal to the preset child node number threshold, and the number of child nodes of the current node is greater than or equal to the preset child node number threshold, it means that the current node and the parent node belong to different laser beams, the parent node is the head node of a laser beam, and the current node is the head node of another laser beam. The decoder determines the intra-frame prediction value corresponding to the current node based on the number of decoded head nodes in the point cloud, the prediction index and the current prediction list. In this case, the current prediction list is the preset prediction list.

In some embodiments, when the current node does not have a parent node, it indicates that the current node is a root node, and the number of child nodes of the current node is greater than or equal to a preset child node number threshold. The decoder can determine the current beam prediction value according to the number of decoded head nodes in the point cloud; and determine the current radius prediction value and the current azimuth prediction value according to the prediction value corresponding to the prediction index in the current prediction list.

In an embodiment of the present application, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the decoder can determine the current beam prediction value based on the number of decoded head nodes in the point cloud; and determine the current radius prediction value and the current azimuth prediction value based on the prediction value corresponding to the prediction index in the current prediction list.

Exemplarily, when the number of child nodes of the parent node of the current node P is greater than or equal to the preset child node number threshold, the current prediction list is a preset prediction list, which includes at least one pair of prediction values When the number of child nodes of point P is greater than or equal to the preset child node number threshold, the predicted value of point P is in, are the radius prediction value and azimuth prediction value corresponding to the prediction index j in the current prediction list, that is, the current prediction radius prediction value and the current azimuth prediction value; i is the number of encoded head nodes, and the initial value is 0. i is used as the current beam prediction value. The case where the current node has no parent node is similar to the above example and will not be repeated here.

In some embodiments, when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, it indicates that the current node and the parent node belong to the same laser beam, the parent node is the head node of the laser beam, and the current node is the second node of the laser beam. The decoder can determine the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node of the current node, the prediction index, and the current prediction list.

In some embodiments, when the number of child nodes of a parent node is less than a preset child node number threshold and greater than 0, it indicates that the current node and the parent node belong to the same laser beam, and neither the current node nor the parent node is a head node. The reconstruction information, prediction index and current prediction list are used to determine the intra-frame prediction value corresponding to the current node.

In the embodiment of the present application, when the prediction index corresponds to the first pair of prediction values in the current prediction list, the decoder determines the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node. The reconstruction information of the parent node includes: the parent node radius reconstruction value, the parent node azimuth reconstruction value, and the parent node beam index reconstruction value. The decoder determines the parent node radius reconstruction value as the current radius prediction value; determines the parent node azimuth reconstruction value as the current azimuth prediction value; determines the parent node beam index reconstruction value as the current beam prediction value, thereby determining the intra-frame prediction value corresponding to the current node.

In the embodiment of the present application, when the prediction index corresponds to the nth pair of prediction values in the current prediction list, the decoder determines the current radius prediction value according to the radius prediction value in the nth pair of prediction values; n is an integer greater than 1; the current azimuth prediction value is determined according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value, and the preset azimuth sampling interval; the current beam prediction value is determined according to the parent node beam index reconstruction value. The decoder determines the intra-frame prediction value corresponding to the current node according to the radius prediction value, azimuth prediction value, and laser beam prediction value corresponding to the current node.

For example, when the number of child nodes of the parent node of the current node P is less than the preset child node number threshold and greater than 0, when the prediction index corresponds to the first pair of prediction values in the current prediction list, the intra-frame prediction value of point P can be where r ₀ , and i ₀ are respectively the current radius prediction value, the current azimuth prediction value and the current beam prediction value, r ₀ , and i ₀ are determined by the parent node radius reconstruction value, parent node azimuth reconstruction value and parent node beam index reconstruction value of the parent node of point P, respectively. When the prediction index corresponds to the jth pair of prediction values (j=n-1) in the current prediction list, the intra-frame prediction value of point P can be Among them, _rj is the current radius prediction value, is the current azimuth prediction value, i ₀ is the current beam prediction value _. are respectively the radius prediction value and the azimuth prediction value in the jth pair of prediction values in the current prediction list, is the azimuth sampling interval. When k=0, otherwise in Representatives The example where the number of child nodes of the parent node is greater than or equal to the preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0 is similar to the above example and will not be repeated here.

In the embodiment of the present application, when the decoder performs the code stream parsing process of S101, it can also parse the code stream to obtain the quantization coefficient and the prediction residual. The decoder uses the quantization coefficient to dequantize the prediction residual, and when the current node uses intra-frame prediction coding, the geometric reconstruction information of the current node is restored according to the intra-frame prediction value corresponding to the current node and the dequantized prediction residual, and then the final reconstructed geometric information of the current node is obtained by performing inverse coordinate transformation and other processing on the geometric reconstruction information.

It can be understood that in the embodiment of the present application, the decoder can determine the prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree, so that each laser beam in the point cloud can be decoded independently. The decoding of different laser beams does not affect each other and can be executed in parallel, thereby reducing the decoding delay, improving the decoding efficiency, and thus improving the decoding performance.

In some embodiments, the prediction list includes at least one pair of prediction values, each pair of prediction values includes a radius prediction value and an azimuth prediction value. That is, the prediction list includes: at least one radius prediction value and at least one azimuth prediction value. Before the decoder determines that the preset prediction list is the current prediction list, the preset prediction list can be determined by S201 or S202:

S201. Use the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or use the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list.

In an embodiment of the present application, when initializing the prediction list, the minimum radius or maximum radius of the cylindrical coordinates of the midpoint of the point cloud to be decoded can be used to initialize at least one radius prediction value in the prediction list; and/or, at least one azimuth prediction value can be initialized using a preset minimum azimuth or azimuth median value, thereby obtaining a preset prediction list.

For example, in the point cloud to be decoded input to the decoder, the minimum radius may be r _min , and the maximum radius may be r _max ; the minimum azimuth angle may be preset can be -180 ^° , and the preset azimuth median value can be 0. Then the preset prediction list can include: (r _min ,0), (r _max ,0), One or more of. The specific selection is made according to the actual situation, and the embodiment of the present application is not limited. It should be noted that after initialization, at least one pair of prediction values included in the preset prediction list can be the same or different.

S201. According to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, at least one radius prediction value in the preset prediction list is determined in an incremental manner for initialization.

Exemplarily, the decoder can set a phased initial prediction value for each radius prediction value in the prediction list based on the minimum radius value according to the geometric accuracy of the point cloud sequence to obtain a preset prediction list. Exemplarily, the geometric accuracy of the Ford sequence in the G-PCC standard rotating lidar data set is 18 bits, and the 4 pairs of prediction values in the preset prediction list, such as PRL ₀ to PRL _3, can be initialized to PRL ₀ = (r _min , 0); PRL ₁ = (r _min +2 ¹⁰ , 0); PRL ₂ = (r _min +2 ¹² , 0); PRL ₃ = (r _min +2 ¹⁴ , 0).

It can be understood that the prediction list is initialized by a preset minimum radius or a maximum radius; and/or the prediction list is initialized by a preset minimum azimuth or a preset median azimuth to obtain a preset prediction list, which is better than the current initialization. When optimizing the prediction list, the radius prediction value and the azimuth prediction value in the preset list are initialized to 0, which can reduce the residual between the actual value of the node and the prediction value obtained according to the preset prediction list, thereby improving the encoding and decoding performance.

In some embodiments, in the above S102, when the number of child nodes of the parent node is less than the preset child node number threshold and greater than 0, the prediction list corresponding to the previous decoded node is updated based on the reconstruction information of the previous decoded node of the current node, and the process of determining the current prediction list can be implemented by the following process:

When the number of child nodes of the parent node of the current node P is less than the preset child node number threshold and greater than 0, illustratively, when the number of child nodes of the parent node of the current node P is equal to 1, if the absolute value of the radius residual of the previous decoded node is determined to be |r _res |＞th based on the reconstruction information of the previous decoded node of the current node P, it means that the laser beam has scanned a new object. As shown in FIG5 , the decoder can discard the last pair of radius prediction value and azimuth prediction value (i.e., a pair of radius prediction value and azimuth prediction value with j=3) in the prediction list corresponding to the previous decoded node, and replace the last pair of radius prediction value and azimuth prediction value in the reconstruction information of the previous decoded node with j=3. Insert it to the head of the prediction list, that is, move the values at positions j=0 to j=2 in the prediction list back one position in turn to positions j=1 to j=3, and then set the value at position j=0 As the first pair of radius prediction value and azimuth prediction value, a prediction list corresponding to the current node is obtained.

If the absolute value of the radius residual of the previous decoded node |r _res |≤th, it means that the laser beam has scanned an object that already exists in the prediction list. The decoder adds the prediction index (predIdx) corresponding to the prediction value of the previous decoded node to the prediction value corresponding to the predIdxth in the prediction list of the previous decoded node. Move to the head of the prediction list and use the reconstruction information of the previous decoded node As shown in Figure 6, taking predIdx=2 as an example, the prediction list of the previous decoded node is moved back one position from j=0 to j=predIdx-1, and then the first pair of prediction values of the prediction list is set. Get the current prediction list corresponding to the current node.

In some embodiments, the decoder may also perform S401-S403 as shown in FIG. 7 as follows:

S401: Determine a residual decoding context and/or an inter-frame flag decoding context corresponding to a current node based on the number of child nodes of a parent node.

In the embodiment of the present application, the decoder can determine the prediction residual coding and inter-frame prediction flag coding corresponding to the current node through the code stream parsing process in S101. The decoder determines the residual decoding context corresponding to the current node, so as to decode the prediction residual coding using the residual decoding context and determine the prediction residual corresponding to the current node. The decoder determines the inter-frame flag decoding context corresponding to the current node, so as to decode the inter-frame prediction flag coding using the inter-frame flag decoding context and determine the inter-frame prediction flag corresponding to the current node.

The embodiment of the present application provides a method for determining the residual decoding context and/or inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node. In actual application, the method provided by the embodiment of the present application can be used to determine the residual decoding context and inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node. The method provided by the embodiment of the present application can also be used to determine any one of the residual decoding context and inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node, and then determine the other of the residual decoding context and inter-frame flag decoding context in combination with the current decoding method. The specific selection is made according to the actual situation, and the embodiment of the present application is not limited.

In some embodiments, the prediction residual includes: an azimuth prediction residual; accordingly, the residual decoding context includes: an azimuth residual context. In some embodiments, the prediction residual includes: a radius prediction residual; accordingly, the residual decoding context includes: a radius residual context. Below, the process of determining the azimuth residual context, radius residual context, and inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node in the embodiment of the present application is described respectively.

Regarding the process of determining the azimuth residual context corresponding to the current node based on the number of child nodes of the parent node, in some embodiments, the decoder determines the azimuth residual context based on a preset fourth index value when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In the embodiment of the present application, as mentioned above, when the number of child nodes of the parent node is greater than or equal to the preset child node number threshold, it indicates that the parent node is a head node. In order to reduce the inter-line dependency of the decoding process, the decoder determines the azimuth context index as the preset fourth index value, and determines the azimuth residual context corresponding to the current node based on the azimuth context index. Thus, the context of residual decoding of the current node is determined without relying on the decoding information of the previous decoded node, which reduces the inter-line dependency and improves the decoding efficiency and decoding performance.

Exemplarily, the azimuth context index may be _resPhiOldSign, and the preset fourth index value may be 3. If the number of child nodes of the parent node of the current node P is 2, the decoder initializes _resPhiOldSign corresponding to point P to 3, and determines the azimuth residual context based on _resPhiOldSign.

In some embodiments, the G-PCC may include a 2x5 first preset context list, and the decoder determines the azimuth residual context used for decoding the azimuth residual in the first preset context list according to the azimuth context index _resPhiOldSign. As shown in formulas (1) and (2), it is as follows:
ctx _sign =ctxTab[ctxL][interFlag? 4:_resPhiOldSign] (1)
ctxL=interFlag? (refNodeIdx>1?1:0):I _previous (2)

In formula (1), ctxTab represents the first preset context list; interFlag is the inter-frame prediction flag, which is a Boolean value, indicating whether the current node uses inter-frame prediction; refNodeIdx indicates which inter-frame prediction point is used when the current node uses inter-frame prediction; I _previous is a Boolean value indicating whether the selected prediction value is a parent node. In this way, based on _resPhiOldSign, the azimuth residual context can be determined in the first preset context list.

It can be understood that in the embodiment of the present application, when the number of child nodes of the parent node is greater than or equal to the preset child node number threshold, the decoder determines the azimuth context index as the preset fourth index value, and then determines the azimuth residual context corresponding to the current node based on the azimuth context index. Thus, the context of residual decoding of the current node is determined without relying on the decoding information of the previous decoded node, which reduces the inter-line dependency and improves the decoding efficiency and decoding performance.

In some embodiments, when the number of child nodes of a parent node is less than a preset child node number threshold and greater than 0, the decoder determines the azimuth residual context corresponding to the current node based on a previous decoded node of the current node.

In the embodiment of the present application, when the number of child nodes of the parent node is less than the preset child node number threshold and greater than 0, the previous decoded node of the current node is the parent node. The decoder determines the azimuth context index based on the previous decoded node of the current node; and determines the azimuth residual context corresponding to the current node based on the azimuth context index. Among them, determining the azimuth context index based on the previous decoded node of the current node includes the following process:

When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value;

When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is less than or equal to a preset sign threshold, determining the azimuth context index based on a preset second index value;

When the previous decoded node is inter-frame prediction decoding, and the inter-frame prediction point used for decoding belongs to the first m candidate inter-frame prediction points corresponding to the previous decoded node, the azimuth context index is determined based on a preset third index value; m is a positive integer not less than 1;

When the previous decoded node is decoded by inter-frame prediction and the inter-frame prediction point used for decoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous decoded node, the azimuth context index is determined based on a preset fourth index value.

Exemplarily, if the number of child nodes of the parent node of point P is equal to 1, the _resPhiOldSign of point P is updated according to the information of the previous decoded point. If the previous decoded point adopts intra-frame prediction and the sign of its azimuth residual is greater than 0, then _resPhiOldSign = 0, where 0 is the preset first index value; otherwise _resPhiOldSign = 1, where 1 is the preset second index value. If the previous decoded point adopts inter-frame prediction, and the inter-frame prediction point adopted is one of the first two inter-frame prediction points, then _resPhiOldSign = 2, where 2 is the preset third index value; otherwise _resPhiOldSign = 3, where 3 is the preset fourth index value.

In some embodiments, when the number of child nodes of the parent node of the current node is greater than or equal to a preset child node number threshold, and when the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, the decoder may also determine the azimuth context index based on the parent node of the current node; and determine the azimuth residual context based on the azimuth context index. In this case, the parent node of the current node is the previous decoded node of the current node, and the process of the decoder determining the azimuth context index based on the parent node of the current node is consistent with the above-mentioned process description of determining the azimuth context index based on the previous decoded node of the current node, and will not be repeated here.

It should be noted that, in some embodiments, when the current node does not have a parent node, the decoder may also determine the azimuth residual context corresponding to the current node based on a preset fourth index value. The specific process is consistent with the above-mentioned same process description, and will not be repeated here.

It can be understood that the decoder determines the azimuth residual decoding context based on the number of child nodes of the parent node, thereby determining the context of the residual decoding of the current node without relying on the decoding information of the previous decoded node, reducing inter-line dependence and improving decoding efficiency and decoding performance.

Regarding the process of determining the radius residual context corresponding to the current node based on the number of child nodes of the parent node, in some embodiments, the decoder determines at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold; and determines the radius residual context corresponding to the current node based on at least one of the first radius context index, the second radius context index, and the third radius context index.

In the embodiment of the present application, the first radius context index is used to indicate whether the previous decoded point adopts inter-frame prediction; the second radius context index is used to indicate whether the previous decoded point adopts inter-frame prediction; The radius context index is used to indicate whether the azimuth sampling interval of the previous decoded point is equal to zero; the third radius context index is used to indicate whether the sign of the azimuth residual of the previous point is less than 0.

Exemplarily, the first radius context index may be prevInterFlag, the second radius context index may be I _penulm , and the third radius context index may be S _res,prec . Among them, prevInterFlag, I _penulm and S _res,prec are all Boolean values, and the initial value is false. The preset first flag value may be false, that is, 0. When the number of child nodes of the parent node of the current point P is 2, the decoder sets at least one of prevInterFlag, I _penulm , and S _res,prec corresponding to point P to false, and determines the radius residual context corresponding to the current node based on at least one of prevInterFlag, I _penulm , and S _res,prec .

In some embodiments, the G-PCC may include a second preset context list of 3x2x8, and the decoder may determine the radius residual context corresponding to the current node in the second preset context list based on at least one of the first radius context index, the second radius context index, and the third radius context index according to formula (2) to formula (4), as follows:
ctx _sign =ctxTab[interFlag? 2:prevInterFlag][ctxL][ctxR] (3)
ctxR＝(I _penulm ?4:0)+(I _last ?2:0)+S _res,prec (4)

In formula (4), I _last is a Boolean value used to indicate whether the azimuth sampling interval of the current node is equal to zero.

In some embodiments, when the number of child nodes of a parent node is less than a preset child node number threshold and greater than 0, the decoder determines at least one of the first radius context index, the second radius context index, and the third radius context index based on the previous decoded node of the current node; based on at least one of the first radius context index, the second radius context index, and the third radius context index, determines the radius residual context corresponding to the current node.

In some embodiments, the process of the decoder determining at least one of the first radius context index, the second radius context index, and the third radius context index according to a decoded node before the current node may include:

The first radius context index is determined according to whether the previous decoded node adopts inter-frame prediction; the second radius context index is determined according to whether the azimuth sampling interval of the previous decoded node is zero; the third radius context index is determined according to whether the sign of the radius residual of the previous decoded node is less than a preset sign threshold.

Exemplarily, if the number of child nodes of the parent node of the current node P is equal to 1, prevInterFlag is updated according to whether the previous decoded point, that is, the parent node of point P, adopts inter-frame prediction. I _penulm is updated according to the azimuth sampling interval of the previous decoded point. If the azimuth sampling interval of the previous decoded point is not equal to 0, I _penulm = false. If the azimuth sampling interval of the previous decoded point is equal to 0, I _penulm = true. S _res,prec is updated according to the sign of the radius residual of the previous decoded point. If the sign of the radius residual of the previous decoded point is greater than 0 (0 is the preset sign threshold), S _res,prec = false; if the sign of the radius residual of the previous decoded point is less than 0, S _res,prec = true.

In some embodiments, when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, the decoder may also determine at least one of the first radius context index, the second radius context index, and the third radius context index based on the parent node of the current node; and determine the radius residual context corresponding to the current node based on at least one of the first radius context index, the second radius context index, and the third radius context index. In this case, the parent node of the current node is equivalent to the previous decoded node of the current node, and the process by which the decoder determines at least one of the first radius context index, the second radius context index, and the third radius context index based on the parent node of the current node is consistent with the process description of the decoder determining at least one of the first radius context index, the second radius context index, and the third radius context index based on the previous decoded node of the current node, and will not be repeated here.

It should be noted that, in some embodiments, when the current node does not have a parent node, the decoder may also determine at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index, and the third radius context index, determine the radius residual context corresponding to the current node. The specific process is consistent with the above-mentioned same process description and will not be repeated here.

It can be understood that the decoder determines the radius residual decoding context based on the number of child nodes of the parent node, thereby determining the context of the residual decoding of the current node without relying on the decoding information of the previous decoded node, reducing inter-line dependencies and improving decoding efficiency and decoding performance.

Regarding the process of determining the inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node, in some embodiments, when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, the decoder determines the preset initial value as the inter-frame flag decoding context corresponding to the current node.

Exemplarily, the inter-frame flag decoding context may be interFlagBuffer. If the number of child nodes of the parent node of the current node P is 2, the interFlagBuffer of point P is initially 0.

In some embodiments, when the number of child nodes of a parent node is less than a preset child node number threshold and greater than 0, the value of the inter-frame prediction flag of at least one decoded node before the current node is determined as the inter-frame flag decoding context corresponding to the current node.

Exemplarily, the decoder may set a buffer (interFlagBuffer) for storing the inter-frame prediction flags (interFlag) of the five decoded nodes before the current node. If the number of child nodes of the parent node of the current node P is 1, the interFlagBuffer of point P stores the interFlag values of the first five decoded points.

It should be noted that, in some embodiments, when the current node does not have a parent node, the decoder may also determine the preset initial value as the inter-frame flag decoding context corresponding to the current node.

S402. Based on the residual decoding context, decode the prediction residual encoding corresponding to the current node, and/or, based on the inter-frame flag decoding context, decode the inter-frame prediction flag encoding corresponding to the current node to determine the prediction residual and/or inter-frame prediction flag corresponding to the current node.

S403: When the inter-frame prediction flag indicates that the current node does not adopt inter-frame prediction coding, determine the geometric prediction information corresponding to the current node based on the prediction residual and the intra-frame prediction value.

In an embodiment of the present application, the decoder determines the residual decoding context based on the above process and uses the residual decoding context to decode the prediction residual code to determine the prediction residual corresponding to the current node. The decoder determines the inter-frame flag decoding context and uses the inter-frame flag decoding context to decode the inter-frame prediction flag code to determine the inter-frame prediction flag corresponding to the current node. If the inter-frame prediction flag indicates that the current node does not use inter-frame prediction coding, it means that the prediction residual is the prediction residual corresponding to the intra-frame prediction value. The decoder recovers and reconstructs the geometric information based on the prediction residual and the intra-frame prediction value, and then determines the geometric prediction information corresponding to the current node.

It can be understood that in the embodiment of the present application, the inter-frame flag decoding context is determined based on the number of child nodes of the parent node, so that the context of residual decoding of the current node is determined without relying on the decoding information of the previous decoded node, thereby reducing inter-line dependence and improving decoding efficiency and decoding performance.

In some embodiments, after the above S402, as shown in FIG8, S501-S502 may be included as follows:

S501 . When the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, inter-frame prediction is performed on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node.

S502: Determine geometric prediction information corresponding to the current node based on the prediction residual and the inter-frame prediction value.

In the embodiment of the present application, when the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, decoding needs to be performed based on the inter-frame prediction value combined with the prediction residual. Here, the decoder can perform inter-frame prediction on the current node based on the parent node of the current node to determine the inter-frame prediction value corresponding to the current node.

In some embodiments, the decoder determines an initial reference point on the same laser beam as the parent node and having the same azimuth as the parent node in the reference point cloud of the point cloud; determines a first reference point and a second reference point on the same laser beam of the reference point cloud whose azimuth is greater than that of the initial reference point; and determines an inter-frame prediction value corresponding to the current node based on the first reference point and the second reference point. The reference point cloud is a reference point cloud after global motion compensation.

Exemplarily, for the current node P on the i-th line (i-th laser beam) in the prediction tree, first determine the parent node (ParDecP0) of point P; in the i-th line in the prediction tree of the reference point cloud after global motion compensation, determine the point with the same quantized azimuth as ParDecP0 as the initial reference point (GMCrefFrameP0); in the i-th line in the prediction tree of the reference point cloud after global motion compensation, determine the first point (GMCinterPredPt) with an azimuth greater than that of GMCrefFrameP0 as the first reference point, and then determine the first point (AdditionalGMC interPredPt) with an azimuth greater than that of GMC interPredPt as the second reference point, combine the first reference point and the second reference point with the original two inter-frame prediction candidate points for inter-frame prediction, and determine the inter-frame prediction value corresponding to the current node.

It can be understood that when searching for reference points in inter-frame prediction, the decoder searches according to the parent node of the current node, which improves the search efficiency and search accuracy, thereby improving the efficiency and performance of inter-frame prediction, and further improving the decoding performance.

An optional encoding method applied to an encoder provided in an embodiment of the present application is described below.

Refer to Figure 9, which is an optional flow chart of the encoding method provided in an embodiment of the present application, which will be explained in conjunction with the steps shown in Figure 9.

S601, determining a prediction tree corresponding to the point cloud.

S602: Determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree.

In some embodiments, when the number of child nodes of a parent node is greater than or equal to a preset child node number threshold, the encoder determines that the preset prediction list is the current prediction list.

In some embodiments, when the number of child nodes of a parent node is less than a preset child node number threshold and greater than 0, the encoder updates the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous encoded node to determine the current prediction list.

In some embodiments, when the current node does not have a parent node, the encoder determines that the preset prediction list is the current prediction list. Test list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value. Before determining the preset prediction list as the current prediction list, the encoder uses the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or uses the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list, thereby determining the preset prediction list.

In some embodiments, before determining that a preset prediction list is the current prediction list, the encoder determines at least one radius prediction value in the preset prediction list in an incremental manner according to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, thereby determining the preset prediction list.

In the embodiment of the present application, the process of S601-S602 is consistent with the same process description in S101-S102, and will not be repeated here.

S603: Predict the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node.

In an embodiment of the present application, the encoder predicts the current node based on at least one pair of prediction values in the current prediction list, thereby determining at least one intra-frame prediction value corresponding to the current node.

In some embodiments, when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is greater than or equal to a preset child node number threshold, the encoder determines at least one intra-frame prediction value corresponding to the current node based on the number of encoded head nodes in the point cloud and the current prediction list.

In some embodiments, when the number of child nodes of a parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, the encoder determines at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list.

In some embodiments, when the number of child nodes of a parent node is less than a preset child node number threshold and greater than 0, the encoder determines at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list.

It should be noted that, in some embodiments, when the current node does not have a parent node, it indicates that the number of child nodes of the current node is greater than or equal to a preset child node number threshold. The encoder determines at least one intra-frame prediction value corresponding to the current node based on the number of encoded head nodes in the point cloud and the current prediction list.

In some embodiments, the encoder determines a current beam prediction value based on the number of decoded head nodes in the point cloud; determines at least one intra-frame prediction value corresponding to the current node based on at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list, combined with the current beam prediction value.

In some embodiments, each of the at least one intra-frame prediction value includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; the above-mentioned determining, based on the number of encoded head nodes in the point cloud and the current prediction list, at least one intra-frame prediction value corresponding to the current node includes:

Determine the current beam prediction value according to the number of decoded head nodes in the point cloud; determine at least one intra-frame prediction value corresponding to the current node according to at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list, combined with the current beam prediction value.

In some embodiments, determining at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list includes:

For the first intra-frame prediction value among at least one intra-frame prediction value, determine the current radius prediction value, current azimuth prediction value and current beam prediction value in the first intra-frame prediction value according to the parent node radius reconstruction value, parent node azimuth reconstruction value and parent node beam index reconstruction value in the reconstruction information of the parent node; for the nth intra-frame prediction value among at least one intra-frame prediction value, determine the current radius prediction value in the nth intra-frame prediction value according to the radius prediction value in the nth pair of prediction values in the current prediction list; n is an integer greater than 1; determine the current azimuth prediction value in the nth intra-frame prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value and the preset azimuth sampling interval; determine the current beam prediction value in the nth intra-frame prediction value according to the parent node beam index reconstruction value.

For example, when the number of child nodes of the parent node of the current node P is 2, and the number of child nodes of point P is 2, the prediction list corresponding to point P is the preset prediction list At least one predicted value of point P Where i is the number of encoded head nodes, that is, the number of nodes whose number of encoded child nodes is 2, and the initial value of i is 0.

For example, if the number of child nodes of the parent node of the current node P is 2, and the number of child nodes of point P is 1, the current prediction list of point P is a preset prediction list, which contains at least one pair of prediction values The encoder reconstructs the value r ₀ based on the radius of the parent node and the azimuth of the parent node Reconstruct the value i ₀ with the parent node beam index to determine the first intra-frame prediction value Based on the nth pair of prediction values in the current prediction list, determine the nth intra prediction value Thus, at least one intra-frame prediction value is determined. Wherein, j=n-1.

For example, when the number of child nodes of the parent node of the current node P is equal to 1, the encoder reconstructs the values r ₀ , Parent node azimuth reconstruction value Reconstruct the value i ₀ with the parent node beam index to determine the first intra-frame prediction value Based on the nth pair of prediction values in the current prediction list, determine the nth intra prediction value Thus, at least one intra-frame prediction value is determined. Wherein, j=n-1.

S604: Determine the geometric information encoding corresponding to the current node based on at least one intra-frame prediction value.

In the embodiment of the present application, the encoder can determine the target intra-frame prediction value from at least one intra-frame prediction value according to the rate-distortion cost; and perform inter-frame prediction on the current node to determine the inter-frame prediction value corresponding to the current node; and determine the prediction value corresponding to the current node from the target intra-frame prediction value and the inter-frame prediction value according to the rate-distortion cost. The encoder determines the residual according to the true value and the prediction value of the current node, performs encoding based on the residual and the prediction value, and determines the geometric information encoding corresponding to the current node.

Here, it should be noted that, when the prediction value corresponding to the current node is the target intra-frame prediction value, the encoder determines the prediction index according to the prediction value corresponding to the target intra-frame prediction value in the current prediction list, encodes the prediction index and residual information, generates geometric information code and transmits it to the decoding end.

It can be understood that in the embodiment of the present application, the prediction list corresponding to the current node is determined based on the number of child nodes of the parent node in the prediction tree, so that each laser beam in the point cloud can be encoded independently, and the encoding between different laser beams does not affect each other and can be executed in parallel, thereby reducing the encoding delay, improving the encoding efficiency, and thus improving the encoding performance.

In some embodiments, determining the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value includes:

Determining a prediction residual corresponding to the current node based on the at least one intra-frame prediction value;

Determine, based on the number of child nodes of the parent node, a residual coding context and/or an inter-frame flag coding context corresponding to the current node;

Based on the residual coding context, the prediction residual corresponding to the current node is encoded, and/or based on the inter-frame flag coding context, the inter-frame prediction flag corresponding to the current node is encoded, the prediction residual coding and/or inter-frame prediction flag coding corresponding to the current node are determined, and the geometric information coding is determined based on the prediction residual coding and/or inter-frame prediction flag coding.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual coding context includes: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual coding context corresponding to the current node includes:

When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, the azimuth residual context is determined based on a preset fourth index value.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual coding context includes: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual coding context corresponding to the current node includes:

When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node.

In some embodiments, the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; the method further comprises:

When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value.

In some embodiments, the determining, based on a previously encoded node of the current node, an azimuth residual context corresponding to the current node comprises:

When the previous coded node is intra-frame prediction coded and the sign of the azimuth residual of the previous coded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value;

When the previous coded node is intra-prediction coded and the sign of the azimuth residual of the previous coded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value;

In a case where the previous coded node is inter-frame prediction coded and the inter-frame prediction point used for coding belongs to the first m candidate inter-frame prediction points corresponding to the previous coded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1;

When the previous encoded node is inter-frame prediction encoded, and the inter-frame prediction point used for encoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous encoded node, determining the azimuth context index based on a preset fourth index value;

Based on the azimuth context index, determine the azimuth residual context corresponding to the current node.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual coding context includes: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual coding context corresponding to the current node includes:

When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine the azimuth context index based on the parent node;

Based on the azimuth context index, the azimuth residual context is determined.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; and based on the number of child nodes of the parent node, determining the residual coding context corresponding to the current node includes:

In a case where the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; and based on the number of child nodes of the parent node, determining the residual decoding context corresponding to the current node includes:

When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, determine at least one of a first radius context index, a second radius context index and a third radius context index according to a previous encoded node of the current node;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises:

In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the determining, according to a previous encoded node of the current node, at least one of the first radius context index, the second radius context index, and the third radius context index comprises at least one of the following:

Determining the first radius context index according to whether the previous encoded node adopts inter-frame prediction;

Determining the second radius context index according to whether the azimuth sampling interval of the previous encoded node is zero;

The third radius context index is determined according to whether the sign of the radius residual of the previous encoded node is less than a preset sign threshold.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; and based on the number of child nodes of the parent node, determining the residual coding context corresponding to the current node includes:

When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine at least one of the first radius context index, the second radius context index, and the third radius context index based on the parent node;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, determining the prediction residual corresponding to the current node based on the at least one intra-frame prediction value includes:

Performing inter-frame prediction on the current node according to the parent node to determine an inter-frame prediction value corresponding to the current node;

Determining geometric prediction information of the current node based on rate-distortion costs of the at least one intra-frame prediction value and the inter-frame prediction value;

Based on the geometric prediction information, a prediction residual corresponding to the current node is determined.

In some embodiments, performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node includes:

In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node;

Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point;

Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined.

In some embodiments, determining the inter-frame flag coding context corresponding to the current node based on the number of child nodes of the parent node includes:

In a case where the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, a preset initial value is determined as the inter-frame flag coding context corresponding to the current node.

In some embodiments, based on the number of child nodes of the parent node, the inter-frame flag bit decoding corresponding to the current node is determined. The following, including:

When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the value of the inter-frame prediction flag of at least one encoded node before the current node is determined as the inter-frame flag coding context corresponding to the current node.

In some embodiments, the method further comprises:

In the case that the current node does not have a parent node, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node.

Here, the encoding method in the encoder embodiment corresponds to the decoding method in the above decoder embodiment, and has similar beneficial effects as the decoding method embodiment. For technical details not disclosed in the above encoding method, reference can be made to the description of the corresponding process in the decoder embodiment for understanding.

Next, another optional decoding method applied to a decoder provided in an embodiment of the present application is described.

Refer to Figure 10, which is an optional flowchart of the decoding method provided in an embodiment of the present application, which will be explained in conjunction with the steps shown in Figure 10.

S701, parsing the code stream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node.

In an embodiment of the present application, the decoder parses the bit stream to determine a prediction tree corresponding to the point cloud and a prediction index corresponding to the current node; the prediction tree includes at least one node on a laser beam.

S702: Determine the current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree.

In the embodiment of the present application, the decoder can determine the current prediction list for performing intra-frame prediction on the current node according to the position of the parent node of the current node in the prediction tree.

In some embodiments, when the parent node of the current node is the head node in the prediction tree, the decoder determines the preset prediction list as the current prediction list.

In some embodiments, when the parent node of the current node is not the head node in the prediction tree, the decoder updates the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous decoded node of the current node to determine the current prediction list.

It should be noted that, in some embodiments, when the current node does not have a parent node, the decoder determines the preset prediction list as the current prediction list.

In the embodiment of the present application, the parent node is the head node in the prediction tree, which is equivalent to the number of child nodes of the parent node in the S102 process being greater than or equal to the preset child node number threshold; the parent node is not the head node, which is equivalent to the number of child nodes of the parent node in the S102 process being less than the preset child node number threshold and greater than 0. The above process is consistent with the corresponding process description in S102, and will not be repeated here.

S703: Determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list.

The process of S703 here is consistent with the description of the process of S103 in the aforementioned decoder embodiment, and will not be repeated here.

It can be understood that in the embodiment of the present application, the prediction list corresponding to the current node can be determined according to the position of the parent node of the current node in the prediction tree, so that each laser beam in the point cloud can be decoded independently, and the decoding between different laser beams does not affect each other and can be executed in parallel, thereby reducing the decoding delay, improving the decoding efficiency, and thus improving the decoding performance.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes:

Using the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or,

The preset azimuth minimum value or the preset azimuth median value is used as the azimuth prediction value in the preset prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes:

According to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, at least one radius prediction value in the preset prediction list is determined in an incremental manner.

In some embodiments, determining the intra prediction value corresponding to the current node based on the prediction index and the current prediction list includes:

In the case where the current node is a head node, an intra-frame prediction value corresponding to the current node is determined according to the number of decoded head nodes in the point cloud, the prediction index and the current prediction list.

In some embodiments, determining the intra prediction value corresponding to the current node based on the prediction index and the current prediction list includes:

When the current node is not a head node, an intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node, the prediction index and the current prediction list.

In some embodiments, determining the intra prediction value corresponding to the current node based on the prediction index and the current prediction list includes:

Based on the reconstruction information of the parent node, the prediction index and the current prediction list, determine the node corresponding to the current node. Intra-frame prediction value.

In some embodiments, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining the intra-frame prediction value corresponding to the current node according to the number of decoded head nodes in the point cloud, the prediction index, and the current prediction list includes:

Determining the current beam prediction value according to the number of decoded head nodes in the point cloud;

The current radius prediction value and the current azimuth prediction value are determined according to the prediction value corresponding to the prediction index in the current prediction list.

In some embodiments, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; the determining the geometric information prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index, and the current prediction list includes:

In a case where the prediction index corresponds to the first pair of prediction values in the current prediction list, determining the current beam prediction value, the current radius prediction value, and the current azimuth prediction value according to the parent node beam index reconstruction value, the parent node radius reconstruction value, and the parent node azimuth reconstruction value in the reconstruction information of the parent node;

In a case where the prediction index corresponds to an nth pair of prediction values in the current prediction list, determining the current radius prediction value according to the radius prediction value in the nth pair of prediction values; n is an integer greater than 1;

Determine the current azimuth prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value, and a preset azimuth sampling interval;

The current beam prediction value is determined according to the parent node beam index reconstruction value.

In some embodiments, the method further comprises:

Determine, based on a position of a parent node of the current node in the prediction tree, a residual decoding context and/or an inter-frame flag decoding context corresponding to the current node;

Based on the residual decoding context, the prediction residual code corresponding to the current node is decoded, and/or, based on the inter-frame flag decoding context, the inter-frame prediction flag code corresponding to the current node is decoded to determine the prediction residual and/or inter-frame prediction flag corresponding to the current node; the prediction residual code and the inter-frame prediction flag code are obtained by bitstream parsing;

When the inter-frame prediction flag indicates that the current node is not encoded using inter-frame prediction, geometric prediction information corresponding to the current node is determined based on the prediction residual and the intra-frame prediction value.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual decoding context includes: an azimuth residual context; based on the position of the parent node in the prediction tree, determining the residual decoding context corresponding to the current node includes:

When the parent node is a head node, the azimuth residual context is determined based on a preset fourth index value.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual decoding context includes: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual decoding context corresponding to the current node includes:

When the parent node is not a head node, an azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual decoding context includes: an azimuth residual context; the method further includes:

When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value.

In some embodiments, determining the azimuth residual context corresponding to the current node based on a previous decoded node of the current node includes:

When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value;

When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value;

In a case where the previous decoded node is inter-frame prediction decoding, and the inter-frame prediction point used for decoding belongs to the first m candidate inter-frame prediction points corresponding to the previous decoded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1;

In the case where the previous decoded node is inter-frame prediction decoding, and the inter-frame prediction point used for decoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous decoded node, based on the preset fourth index value azimuth context index;

Based on the azimuth context index, determine the azimuth residual context corresponding to the current node.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual decoding context includes: an azimuth residual context; the method further includes:

When the parent node is a head node and the current node is not a head node, determining an azimuth context index based on the parent node;

Based on the azimuth context index, the azimuth residual context is determined.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; and based on the position of the parent node in the prediction tree, determining the residual decoding context corresponding to the current node includes:

In a case where the parent node is a head node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; and based on the position of the parent node in the prediction tree, determining the residual decoding context corresponding to the current node includes:

In a case where the parent node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index according to a previous decoded node of the current node;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises:

In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the determining, according to a previous decoded node of the current node, at least one of the first radius context index, the second radius context index, and the third radius context index comprises at least one of the following:

Determining the first radius context index according to whether the previous decoded node adopts inter-frame prediction;

Determining the second radius context index according to whether the azimuth sampling interval of the previous decoded node is zero;

The third radius context index is determined according to whether the sign of the radius residual of the previous decoded node is less than a preset sign threshold.

In some embodiments, the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises:

In a case where the parent node is a head node and the current node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index based on the parent node;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the method further comprises:

When the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, inter-frame prediction is performed on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node;

Based on the prediction residual and the inter-frame prediction value, geometric prediction information corresponding to the current node is determined.

In some embodiments, performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node includes:

In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node;

Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point;

Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined.

In some embodiments, determining the inter-frame flag decoding context corresponding to the current node based on the position of the parent node in the prediction tree includes:

In the case where the parent node is a head node, the preset initial value is determined as the inter-frame flag decoding context corresponding to the current node.

In some embodiments, based on the position of the parent node in the prediction tree, the inter-frame flag corresponding to the current node is determined. Bit decoding context, including:

When the parent node is not a head node, the value of the inter-frame prediction flag of at least one decoded node before the current node is determined as the inter-frame flag decoding context corresponding to the current node.

In some embodiments, the method further comprises:

In the case that the current node does not have a parent node, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node.

It should be noted that the above embodiment uses the position of the parent node of the current node in the prediction tree as a judgment condition to determine the residual decoding context and/or the inter-frame flag decoding context. Among them, the parent node is the head node, which is equivalent to the number of child nodes of the parent node in the aforementioned decoder embodiment S401 being greater than or equal to the preset child node number threshold. The parent node is not the head node, which is equivalent to the number of child nodes of the parent node in the aforementioned decoder embodiment S401 being less than the preset child node number threshold and greater than 0. The parent node is the head node, and the current node is not the head node, which is equivalent to the number of child nodes of the parent node in the aforementioned decoder embodiment S401 being greater than or equal to the preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0. The above process is consistent with the process description in the S401 related embodiment, and has similar beneficial effects as the S401 related embodiment. For technical details not disclosed in the above process, please refer to the description of the S401 related embodiment for understanding.

Next, another optional encoding method applied to an encoder provided in an embodiment of the present application is described.

Refer to Figure 11, which is an optional flow chart of the encoding method provided in an embodiment of the present application, which will be explained in conjunction with the steps shown in Figure 11.

S801, determining a prediction tree corresponding to the point cloud.

S802: Determine the current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree.

In some embodiments, when the parent node is a head node in the prediction tree, the encoder determines the preset prediction list as the current prediction list.

In some embodiments, when the parent node is not the head node, the encoder updates the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous encoded node to determine the current prediction list.

It should be noted that, in some embodiments, when the current node does not have a parent node, the encoder determines the preset prediction list as the current prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, the encoder uses the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, uses the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list, thereby determining the preset prediction list.

In some embodiments, the encoder determines at least one radius prediction value in a preset prediction list in an incremental manner based on the geometric accuracy of the point cloud and the minimum radius corresponding to the point cloud, and then determines the preset prediction list based on the at least one radius prediction value.

S803: Predict the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node.

In some embodiments, when the parent node is the head node in the prediction tree and the current node is the head node, at least one intra-frame prediction value corresponding to the current node is determined according to the number of encoded head nodes in the point cloud and the current prediction list.

In some embodiments, when the parent node is a head node and the current node is not a head node, at least one intra-frame prediction value corresponding to the current node is determined based on reconstruction information of the parent node and a current prediction list.

It should be noted that, in some embodiments, when the current node does not have a parent node, it is indicated that the current node is a root node in the prediction tree. The encoder determines at least one intra-frame prediction value corresponding to the current node according to the number of encoded head nodes in the point cloud and the current prediction list.

In some embodiments, when the parent node is not a head node, the encoder determines at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list.

In some embodiments, each of the at least one intra-frame prediction value includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; the above-mentioned determining, based on the number of encoded head nodes in the point cloud and the current prediction list, at least one intra-frame prediction value corresponding to the current node includes:

Determine the current beam prediction value based on the number of decoded head nodes in the point cloud; determine at least one intra-frame prediction value corresponding to the current node based on at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list, combined with the current beam prediction value.

In some embodiments, determining at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list includes:

For a first intra-frame prediction value in at least one intra-frame prediction value, according to the parent node radius reconstruction value, the parent node azimuth reconstruction value and the parent node beam index reconstruction value in the reconstruction information of the parent node, determine the current radius prediction value in the first intra-frame prediction value, The current azimuth prediction value and the current light beam prediction value; for the nth intra-frame prediction value in at least one intra-frame prediction value, determine the current radius prediction value in the nth intra-frame prediction value according to the radius prediction value in the nth pair of prediction values in the current prediction list; n is an integer greater than 1; determine the current azimuth prediction value in the nth intra-frame prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value and the preset azimuth sampling interval; determine the current light beam prediction value in the nth intra-frame prediction value according to the parent node beam index reconstruction value, thereby determining at least one intra-frame prediction value.

S804. Determine the geometric information encoding corresponding to the current node based on at least one intra-frame prediction value.

Here, S804 is consistent with the description of S604 in the above embodiment and will not be repeated here.

It can be understood that in the embodiment of the present application, the prediction list corresponding to the current node is determined according to the position of the parent node in the prediction tree, so that each laser beam in the point cloud can be encoded independently, and the encoding between different laser beams does not affect each other and can be executed in parallel, thereby reducing the encoding delay, improving the encoding efficiency, and thus improving the encoding performance.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual coding context includes: an azimuth residual context; based on the position of the parent node in the prediction tree, determining the residual coding context corresponding to the current node includes:

When the parent node is a head node, the azimuth residual context is determined based on a preset fourth index value.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual coding context includes: an azimuth residual context; based on the position of the parent node in the prediction tree, determining the residual coding context corresponding to the current node includes:

When the parent node is not a head node, an azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node.

In some embodiments, the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; the method further comprises:

When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value.

In some embodiments, the determining the azimuth residual context corresponding to the current node based on a previous encoded node of the current node comprises:

When the previous coded node is intra-frame prediction coded and the sign of the azimuth residual of the previous coded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value;

When the previous coded node is intra-prediction coded and the sign of the azimuth residual of the previous coded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value;

In a case where the previous coded node is inter-frame prediction coded and the inter-frame prediction point used for coding belongs to the first m candidate inter-frame prediction points corresponding to the previous coded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1;

When the previous encoded node is inter-frame prediction encoded, and the inter-frame prediction point used for encoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous encoded node, determining the azimuth context index based on a preset fourth index value;

Based on the azimuth context index, determine the azimuth residual context corresponding to the current node.

In some embodiments, the prediction residual includes: an azimuth prediction residual; the residual coding context includes: an azimuth residual context; based on the position of the parent node in the prediction tree, determining the residual coding context corresponding to the current node includes:

When the parent node is a head node and the current node is not a head node, determining an azimuth context index based on the parent node;

Based on the azimuth context index, the azimuth residual context is determined.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; based on the position of the parent node in the prediction tree, determining the residual coding context corresponding to the current node includes:

In a case where the parent node is a head node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; and based on the position of the parent node in the prediction tree, determining the residual coding context corresponding to the current node includes:

In a case where the parent node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index according to a previous encoded node of the current node;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; the method further comprises:

In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the determining, according to a previous encoded node of the current node, at least one of the first radius context index, the second radius context index, and the third radius context index comprises at least one of the following:

Determining the first radius context index according to whether the previous encoded node adopts inter-frame prediction;

Determining the second radius context index according to whether the azimuth sampling interval of the previous encoded node is zero;

The third radius context index is determined according to whether the sign of the radius residual of the previous encoded node is less than a preset sign threshold.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; based on the position of the parent node in the prediction tree, determining the residual coding context corresponding to the current node includes:

When the parent node is a head node and the current node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index based on the parent node;

Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined.

In some embodiments, the determining, based on the at least one intra-frame prediction value, a prediction residual corresponding to the current node comprises:

Performing inter-frame prediction on the current node according to the parent node to determine an inter-frame prediction value corresponding to the current node;

Determining geometric prediction information of the current node based on rate-distortion costs of the at least one intra-frame prediction value and the inter-frame prediction value;

Based on the geometric prediction information, a prediction residual corresponding to the current node is determined.

In some embodiments, the performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node includes:

In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node;

Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point;

Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined.

In some embodiments, determining the inter-frame flag coding context corresponding to the current node based on the position of the parent node in the prediction tree includes:

In the case where the parent node is the head node in the prediction tree, a preset initial value is determined as the inter-frame flag coding context corresponding to the current node.

In some embodiments, determining the inter-frame flag coding context corresponding to the current node based on the position of the parent node in the prediction tree includes:

When the parent node is not the head node in the prediction tree, the value of the inter-frame prediction flag of at least one coded node before the current node is determined as the inter-frame flag coding context corresponding to the current node.

In some embodiments, the method further comprises:

In the case that the current node does not have a parent node, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node.

It should be noted that the above embodiment uses the position of the parent node of the current node in the prediction tree as a judgment condition to determine the residual decoding context and/or the inter-frame flag decoding context. Wherein, the parent node is a head node, which is equivalent to the number of child nodes of the parent node in the above encoder embodiment being greater than or equal to the preset child node number threshold. The parent node is not a head node, which is equivalent to the number of child nodes of the parent node in the above encoder embodiment being less than the preset child node number threshold and greater than 0. The parent node is a head node, and the current node is not a head node. Node, which is equivalent to the number of child nodes of the parent node in the aforementioned encoder embodiment is greater than or equal to the preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0. The above process is consistent with the process description in the aforementioned encoder embodiment, and has similar beneficial effects as the aforementioned encoder embodiment. For technical details not disclosed in the above process, please refer to the description of the aforementioned encoder embodiment for understanding.

In some embodiments, based on the above encoding and decoding method provided by the embodiment of the present application, as shown in FIG. 12, the beam index value of the 0th laser beam, that is, the node on 0laser is Laser index = 0, and so on. It can be seen that FIG. 12 contains a prediction tree consisting of 4 laser beams. When the decoder enables parallel decoding, or when the encoder enables parallel encoding, since the number of child nodes of the parent node of the current node is greater than or equal to the preset child node threshold, or the parent node of the current node is the head node in the prediction tree, the preset prediction list is used as the prediction list of the current node in the embodiment of the present application. It can be seen that when encoding (decoding) the head node of each laser beam in the prediction tree, the encoder (decoder) will initialize a preset prediction list as the preset prediction list of the laser beam. In other words, each laser beam in the prediction tree has its own prediction list, which is independent of each other. The second node on each laser beam does not need to rely on the information of the previous encoded (decoded) node to determine the prediction list, but uses the preset prediction list or the information of its parent node to determine the prediction list. In this way, parallel encoding and decoding between each laser beam is achieved, which greatly improves the encoding and decoding efficiency and encoding and decoding performance.

The applicant used the point cloud test sequence in Table 1 to compare the encoding method of the embodiment of the present application with the current G-PCC general test software TMC13 V21. The results are shown in Table 1, as follows:

It can be seen that the point cloud coding method of the embodiment of the present application, on the basis of greatly improving the coding efficiency, is also very close to the performance of geometric information prediction coding of the point cloud test sequence compared with the current coding method, with almost no loss, thus bringing better overall coding performance.

The embodiment of the present application provides a decoder 1, as shown in FIG13, comprising:

A first parsing part 10 is configured to parse the code stream to determine a prediction tree corresponding to the point cloud and a prediction index corresponding to the current node;

A first determining part 11 is configured to determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree;

The first prediction part 12 is configured to determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list.

In some embodiments, the first determining part 11 is further configured to determine a preset prediction list as the current prediction list when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In some embodiments, the first determination part 11 is also configured to update the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous decoded node of the current node to determine the current prediction list when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0.

In some embodiments, when the current node does not have a parent node, a preset prediction list is determined to be the current prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the first determination part 11 is also configured to use the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, to use the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the first determination part 11 is also configured to determine at least one radius prediction value in the preset prediction list in an incremental manner based on the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud.

In some embodiments, the first prediction part 12 is further configured to: In the case of the preset child node number threshold, the intra-frame prediction value corresponding to the current node is determined according to the number of decoded head nodes in the point cloud, the prediction index and the current prediction list.

In some embodiments, the first prediction part 12 is further configured to determine the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index and the current prediction list when the number of child nodes of the current node is less than the preset child node number threshold and greater than 0.

In some embodiments, the first prediction part 12 is further configured to determine the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index and the current prediction list.

In some embodiments, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the first prediction part 12 is further configured to determine the current beam prediction value according to the number of decoded head nodes in the point cloud; determine the current radius prediction value and the current azimuth prediction value according to the prediction value corresponding to the prediction index in the current prediction list.

In some embodiments, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the first prediction part 12 is also configured to determine the current beam prediction value, the current radius prediction value and the current azimuth prediction value according to the parent node beam index reconstruction value, the parent node radius reconstruction value and the parent node azimuth reconstruction value in the reconstruction information of the parent node when the prediction index corresponds to the first pair of prediction values in the current prediction list; determine the current radius prediction value according to the radius prediction value in the nth pair of prediction values when the prediction index corresponds to the nth pair of prediction values in the current prediction list; n is an integer greater than 1; determine the current azimuth prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value and a preset azimuth sampling interval; determine the current beam prediction value according to the parent node beam index reconstruction value.

In some embodiments, the decoder 1 also includes a first arithmetic decoding part (not shown in the figure), which is configured to determine the residual decoding context and/or inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node; based on the residual decoding context, decode the prediction residual code corresponding to the current node, and/or, based on the inter-frame flag decoding context, decode the inter-frame prediction flag code corresponding to the current node to determine the prediction residual and/or inter-frame prediction flag corresponding to the current node; the prediction residual code and the inter-frame prediction flag code are obtained by parsing the code stream; when the inter-frame prediction flag indicates that the current node does not adopt inter-frame prediction coding, determine the geometric prediction information corresponding to the current node based on the prediction residual and the intra-frame prediction value.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the first arithmetic decoding part is also configured to determine the azimuth residual context based on a preset fourth index value when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the first arithmetic decoding part is also configured to determine the azimuth residual context corresponding to the current node based on the previous decoded node of the current node when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the first arithmetic decoding part is also configured to determine the azimuth residual context corresponding to the current node based on a preset fourth index value when the current node does not have a parent node.

In some embodiments, the first arithmetic decoding part is further configured to determine the azimuth context index based on a preset first index value when the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is greater than a preset sign threshold;

When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is less than or equal to the preset sign threshold, the azimuth context index is determined based on the preset second index value; when the previous decoded node is inter-frame prediction decoding and the inter-frame prediction point used for decoding belongs to the first m candidate inter-frame prediction points corresponding to the previous decoded node, the azimuth context index is determined based on the preset third index value; m is a positive integer not less than 1; when the previous decoded node is inter-frame prediction decoding and the inter-frame prediction point used for decoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous decoded node, the azimuth context index is determined based on the preset fourth index value; based on the azimuth context index, the azimuth residual context corresponding to the current node is determined.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the first arithmetic decoding part is also configured to determine the azimuth context index based on the parent node when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0; determine the azimuth residual context based on the azimuth context index.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context Below; the first arithmetic decoding part is also configured to determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the first arithmetic decoding part is also configured to determine at least one of a first radius context index, a second radius context index and a third radius context index according to a previous decoded node of the current node when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the first arithmetic decoding part is also configured to, when the current node does not have a parent node, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the first arithmetic decoding part is further configured to determine the first radius context index according to whether the previous decoded node adopts inter-frame prediction; and/or, determine the second radius context index according to whether the azimuth sampling interval of the previous decoded node is zero; and/or, determine the third radius context index according to whether the sign of the radius residual of the previous decoded node is less than a preset sign threshold.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the first arithmetic decoding part is also configured to, when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine at least one of a first radius context index, a second radius context index, and a third radius context index based on the parent node; based on at least one of the first radius context index, the second radius context index, and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the first prediction part 12 is further configured to, when the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, perform inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node; and determine the geometric prediction information corresponding to the current node based on the prediction residual and the inter-frame prediction value.

In some embodiments, the first prediction part 12 is further configured to determine, in the reference point cloud of the point cloud, an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; determine a first reference point and a second reference point on the same laser beam of the reference point cloud with azimuths greater than that of the initial reference point; and determine the inter-frame prediction value corresponding to the current node based on the first reference point and the second reference point.

In some embodiments, the first arithmetic decoding part is further configured to determine a preset initial value as the inter-frame flag decoding context corresponding to the current node when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In some embodiments, the first arithmetic decoding part is also configured to determine the value of the inter-frame prediction flag of at least one decoded node before the current node as the inter-frame flag decoding context corresponding to the current node when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0.

In some embodiments, the first arithmetic decoding part is further configured to determine a preset initial value as an inter-frame flag decoding context corresponding to the current node when the current node does not have a parent node.

The embodiment of the present application provides an encoder 2, as shown in FIG14 , including:

A first construction part 20 is configured to determine a prediction tree corresponding to the point cloud;

A second determining part 21 is configured to determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree;

A second prediction part 22 is configured to predict the current node based on the current prediction list and determine at least one intra-frame prediction value corresponding to the current node;

The first encoding part 23 is configured to determine the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value.

In some embodiments, the second determining part 21 is further configured to determine a preset prediction list as the current prediction list when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In some embodiments, the second determination part 21 is further configured to update the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous encoded node to determine the current prediction list when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0.

In some embodiments, the second determining part 21 is further configured to determine a preset prediction list as the current prediction list when the current node does not have a parent node.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value; the second determination part 21 is also configured to use the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, use the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the second determination part 21 is also configured to determine at least one radius prediction value in the preset prediction list in an incremental manner based on the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud.

In some embodiments, the second prediction part 22 is further configured to determine at least one intra-frame prediction value corresponding to the current node based on the number of encoded head nodes in the point cloud and the current prediction list when the number of child nodes of the current node is greater than or equal to the preset child node number threshold.

In some embodiments, the second prediction part 22 is further configured to determine at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list when the number of child nodes of the current node is less than the preset child node number threshold and greater than 0.

In some embodiments, the second prediction part 22 is further configured to determine at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list.

In some embodiments, each of the at least one intra-frame prediction value includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the second prediction part 22 is also configured to determine the current beam prediction value based on the number of decoded head nodes in the point cloud; and determine at least one intra-frame prediction value corresponding to the current node based on at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list, combined with the current beam prediction value.

In some embodiments, each intra-frame prediction value of the at least one intra-frame prediction value includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the second prediction part 22 is also configured to determine, for the first intra-frame prediction value of the at least one intra-frame prediction value, the current radius prediction value, the current azimuth prediction value and the current beam prediction value in the first intra-frame prediction value according to the parent node radius reconstruction value, the parent node azimuth reconstruction value and the parent node beam index reconstruction value in the reconstruction information of the parent node; for the nth intra-frame prediction value of the at least one intra-frame prediction value, determine the current radius prediction value in the nth intra-frame prediction value according to the radius prediction value in the nth pair of prediction values in the current prediction list; n is an integer greater than 1; determine the current azimuth prediction value in the nth intra-frame prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value and the preset azimuth sampling interval; determine the current beam prediction value in the nth intra-frame prediction value according to the parent node beam index reconstruction value.

In some embodiments, the first encoding part 23 is further configured to determine the prediction residual corresponding to the current node based on the at least one intra-frame prediction value; determine the residual coding context and/or inter-frame flag coding context corresponding to the current node based on the number of child nodes of the parent node; encode the prediction residual corresponding to the current node based on the residual coding context, and/or, based on the inter-frame flag coding context, encode the inter-frame prediction flag corresponding to the current node, determine the prediction residual coding and/or inter-frame prediction flag coding corresponding to the current node, and determine the geometric information coding based on the prediction residual coding and/or inter-frame prediction flag coding.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the first encoding part 23 is also configured to determine the azimuth residual context based on a preset fourth index value when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the first encoding part 23 is also configured to determine the azimuth residual context corresponding to the current node based on the previous decoded node of the current node when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the first encoding part 23 is also configured to determine the azimuth residual context corresponding to the current node based on a preset fourth index value when the current node does not have a parent node.

In some embodiments, the first encoding part 23 is further configured to determine the azimuth context index based on a preset first index value when the previous encoded node is intra-frame prediction encoding and the sign of the azimuth residual of the previous encoded node is greater than a preset sign threshold; determine the azimuth context index based on a preset second index value when the previous encoded node is intra-frame prediction encoding and the sign of the azimuth residual of the previous encoded node is less than or equal to the preset sign threshold; In the case where the previous encoded node is inter-frame prediction coded, and the inter-frame prediction point used for encoding belongs to the first m candidate inter-frame prediction points corresponding to the previous encoded node, the azimuth context index is determined based on a preset third index value; m is a positive integer not less than 1; in the case where the previous encoded node is inter-frame prediction coded, and the inter-frame prediction point used for encoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous encoded node, the azimuth context index is determined based on a preset fourth index value; based on the azimuth context index, the azimuth residual context corresponding to the current node is determined.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the first encoding part 23 is also configured to determine the azimuth context index based on the parent node when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0; determine the azimuth residual context based on the azimuth context index.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; the first encoding part 23 is also configured to, when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the first encoding part 23 is also configured to, when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, determine at least one of a first radius context index, a second radius context index and a third radius context index according to the previous encoded node of the current node; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the first encoding part 23 is also configured to, when the current node does not have a parent node, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the first encoding part 23 is further configured to determine at least one of the first radius context index, the second radius context index and the third radius context index according to a previous encoded node of the current node, including at least one of the following:

Determining the first radius context index according to whether the previous encoded node adopts inter-frame prediction;

Determining the second radius context index according to whether the azimuth sampling interval of the previous encoded node is zero;

The third radius context index is determined according to whether the sign of the radius residual of the previous encoded node is less than a preset sign threshold.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; the first encoding part 23 is also configured to determine, based on the parent node, at least one of a first radius context index, a second radius context index, and a third radius context index when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0; based on at least one of the first radius context index, the second radius context index, and the third radius context index, determine the upper and lower radius residuals corresponding to the current node.

In some embodiments, the second prediction part 22 is further configured to perform inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node; determine the geometric prediction information of the current node based on the rate-distortion cost of the at least one intra-frame prediction value and the inter-frame prediction value; and determine the prediction residual corresponding to the current node based on the geometric prediction information.

In some embodiments, the second prediction part 22 is further configured to determine, in the reference point cloud of the point cloud, an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point with azimuths greater than that of the initial reference point; and determine the inter-frame prediction value corresponding to the current node based on the first reference point and the second reference point.

In some embodiments, the first encoding part 23 is further configured to determine a preset initial value as the inter-frame flag coding context corresponding to the current node when the number of child nodes of the parent node is greater than or equal to a preset child node number threshold.

In some embodiments, the first encoding part 23 is also configured to determine the value of the inter-frame prediction flag of at least one encoded node before the current node as the inter-frame flag encoding context corresponding to the current node when the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0.

In some embodiments, the first encoding part 23 is further configured to, when the current node does not have a parent node, The preset initial value is determined as the inter-frame flag decoding context corresponding to the current node.

The embodiment of the present application provides a decoder 3, as shown in FIG15 , including:

The second parsing part 30 is configured to parse the code stream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node;

A third determining part 31 is configured to determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree;

The third prediction part 32 is configured to determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list.

In some embodiments, the third determining part 31 is further configured to determine a preset prediction list as the current prediction list when the parent node is a head node.

In some embodiments, the third determination part 31 is also configured to update the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous decoded node of the current node to determine the current prediction list when the parent node is not the head node in the prediction tree.

In some embodiments, the third determining part 31 is further configured to determine a preset prediction list as the current prediction list when the current node does not have a parent node.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the third determination part 31 is also configured to use the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, to use the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the third determination part 31 is also configured to determine at least one radius prediction value in the preset prediction list in an incremental manner based on the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud.

In some embodiments, the third prediction part 32 is further configured to determine the intra-frame prediction value corresponding to the current node according to the number of decoded head nodes in the point cloud, the prediction index and the current prediction list when the current node is a head node.

In some embodiments, the third prediction part 32 is further configured to determine the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index and the current prediction list when the current node is not a head node.

In some embodiments, the third prediction part 32 is further configured to determine the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index and the current prediction list.

In some embodiments, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the third prediction part 32 is also configured to determine the current beam prediction value according to the number of decoded head nodes in the point cloud; and determine the current radius prediction value and the current azimuth prediction value according to the prediction value corresponding to the prediction index in the current prediction list.

In some embodiments, the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the third prediction part 32 is also configured to determine the current beam prediction value, the current radius prediction value and the current azimuth prediction value according to the parent node beam index reconstruction value, the parent node radius reconstruction value and the parent node azimuth reconstruction value in the reconstruction information of the parent node when the prediction index corresponds to the first pair of prediction values in the current prediction list; determine the current radius prediction value according to the radius prediction value in the nth pair of prediction values when the prediction index corresponds to the nth pair of prediction values in the current prediction list; n is an integer greater than 1; determine the current azimuth prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value and a preset azimuth sampling interval; determine the current beam prediction value according to the parent node beam index reconstruction value.

In some embodiments, the decoder 3 also includes a first arithmetic decoding part (not shown in the figure), which is configured to determine the residual decoding context and/or inter-frame flag decoding context corresponding to the current node based on the position of the parent node in the prediction tree; based on the residual decoding context, decode the prediction residual code corresponding to the current node, and/or, based on the inter-frame flag decoding context, decode the inter-frame prediction flag code corresponding to the current node to determine the prediction residual and/or inter-frame prediction flag corresponding to the current node; the prediction residual code and the inter-frame prediction flag code are obtained by parsing the code stream; when the inter-frame prediction flag indicates that the current node does not adopt inter-frame prediction coding, determine the geometric prediction information corresponding to the current node based on the prediction residual and the intra-frame prediction value.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the second arithmetic decoding part is also configured to determine the azimuth residual context based on a preset fourth index value when the parent node is a head node.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the second arithmetic decoding part is also configured to determine the azimuth residual context corresponding to the current node based on the previous decoded node of the current node when the parent node is not a head node.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the second arithmetic decoding part is also configured to determine the azimuth residual context corresponding to the current node based on a preset fourth index value when the current node does not have a parent node.

In some embodiments, the second arithmetic decoding part is further configured to determine the azimuth context index based on a preset first index value when the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is greater than a preset sign threshold; determine the azimuth context index based on a preset second index value when the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is less than or equal to the preset symbol threshold; determine the azimuth context index based on a preset third index value when the previous decoded node is inter-frame prediction decoding and the inter-frame prediction point used for decoding belongs to the first m candidate inter-frame prediction points corresponding to the previous decoded node; m is a positive integer not less than 1; determine the azimuth context index based on a preset fourth index value when the previous decoded node is inter-frame prediction decoding and the inter-frame prediction point used for decoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous decoded node; and determine the azimuth residual context corresponding to the current node based on the azimuth context index.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual decoding context includes: azimuth residual context; the second arithmetic decoding part is also configured to determine the azimuth context index based on the parent node when the parent node is a head node and the current node is not a head node; and determine the azimuth residual context based on the azimuth context index.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the second arithmetic decoding part is also configured to, when the parent node is a head node, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the second arithmetic decoding part is also configured to determine, when the parent node is not a head node, at least one of a first radius context index, a second radius context index, and a third radius context index based on a previous decoded node of the current node; based on at least one of the first radius context index, the second radius context index, and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the second arithmetic decoding part is also configured to, when the current node does not have a parent node, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the second arithmetic decoding part is further configured to determine the first radius context index according to whether the previous decoded node adopts inter-frame prediction; and/or, determine the second radius context index according to whether the azimuth sampling interval of the previous decoded node is zero; and/or, determine the third radius context index according to whether the sign of the radius residual of the previous decoded node is less than a preset sign threshold.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual decoding context includes: a radius residual context; the second arithmetic decoding part is also configured to, when the parent node is a head node and the current node is not a head node, determine at least one of a first radius context index, a second radius context index and a third radius context index based on the parent node; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the third prediction part 32 is also configured to, when the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, perform inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node; and determine the geometric prediction information corresponding to the current node based on the prediction residual and the inter-frame prediction value.

In some embodiments, the third prediction part 32 is also configured to determine, in the reference point cloud of the point cloud, an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; determine a first reference point and a second reference point on the same laser beam of the reference point cloud whose azimuths are greater than the azimuth of the initial reference point; and determine the inter-frame prediction value corresponding to the current node based on the first reference point and the second reference point.

In some embodiments, the second arithmetic decoding part is further configured to, when the parent node is a head node, Assume that the initial value is determined to be the inter-frame flag decoding context corresponding to the current node.

In some embodiments, the second arithmetic decoding part is further configured to determine the value of the inter-frame prediction flag of at least one decoded node before the current node as the inter-frame flag decoding context corresponding to the current node when the parent node is not a head node.

In some embodiments, the second arithmetic decoding part is further configured to determine a preset initial value as the inter-frame flag decoding context corresponding to the current node when the current node does not have a parent node.

The embodiment of the present application provides an encoder 4, as shown in FIG16 , including:

A second construction part 40 is configured to determine a prediction tree corresponding to the point cloud;

A fourth determining part 41 is configured to determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree;

A fourth prediction part 42 is configured to predict the current node based on the current prediction list and determine at least one intra-frame prediction value corresponding to the current node;

The second encoding part 43 is configured to determine the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value.

In some embodiments, the fourth determining part 41 is further configured to determine a preset prediction list as the current prediction list when the parent node is a head node in the prediction tree.

In some embodiments, the fourth determination part 41 is further configured to update the prediction list corresponding to the previous decoded node based on the reconstruction information of the previous encoded node to determine the current prediction list when the parent node is not a head node.

In some embodiments, the fourth determining part 41 is further configured to determine a preset prediction list as the current prediction list when the current node does not have a parent node.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the fourth determination part 41 is also configured to use the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, use the preset azimuth minimum value or the preset azimuth median value as the azimuth prediction value in the preset prediction list.

In some embodiments, the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the fourth determination part 41 is also configured to determine at least one radius prediction value in the preset prediction list in an incremental manner based on the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud.

In some embodiments, the fourth prediction part 42 is further configured to determine at least one intra-frame prediction value corresponding to the current node according to the number of encoded head nodes in the point cloud and the current prediction list when the current node is a head node.

In some embodiments, the fourth prediction part 42 is further configured to determine at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list when the current node is not a head node.

In some embodiments, the fourth prediction part 42 is further configured to determine at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list.

In some embodiments, each of the at least one intra-frame prediction value includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the fourth prediction part 42 is also configured to determine the current beam prediction value based on the number of decoded head nodes in the point cloud; and determine at least one intra-frame prediction value corresponding to the current node based on at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list, combined with the current beam prediction value.

In some embodiments, each intra-frame prediction value of the at least one intra-frame prediction value includes: a current beam prediction value, a current radius prediction value and a current azimuth prediction value; the fourth prediction part 42 is also configured to determine, for the first intra-frame prediction value of the at least one intra-frame prediction value, the current radius prediction value, the current azimuth prediction value and the current beam prediction value in the first intra-frame prediction value according to the parent node radius reconstruction value, the parent node azimuth reconstruction value and the parent node beam index reconstruction value in the reconstruction information of the parent node; for the nth intra-frame prediction value of the at least one intra-frame prediction value, determine the current radius prediction value in the nth intra-frame prediction value according to the radius prediction value in the nth pair of prediction values in the current prediction list; n is an integer greater than 1; determine the current azimuth prediction value in the nth intra-frame prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value and the preset azimuth sampling interval; determine the current beam prediction value in the nth intra-frame prediction value according to the parent node beam index reconstruction value.

In some embodiments, the second encoding part 43 is further configured to determine the prediction residual corresponding to the current node based on the at least one intra-frame prediction value; determine the residual corresponding to the current node based on the position of the parent node in the prediction tree Coding context and/or inter-frame flag coding context; based on the residual coding context, encoding the prediction residual corresponding to the current node, and/or, based on the inter-frame flag coding context, encoding the inter-frame prediction flag corresponding to the current node, determining the prediction residual coding and/or inter-frame prediction flag coding corresponding to the current node, and determining the geometric information coding based on the prediction residual coding and/or inter-frame prediction flag coding.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the second encoding part 43 is also configured to determine the azimuth residual context based on a preset fourth index value when the parent node is a head node.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the second encoding part 43 is also configured to determine the azimuth residual context corresponding to the current node based on the previous decoded node of the current node when the parent node is not a head node.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the second encoding part 43 is also configured to determine the azimuth residual context corresponding to the current node based on a preset fourth index value when the current node does not have a parent node.

In some embodiments, the second encoding part 43 is further configured to determine the azimuth context index based on a preset first index value when the previous encoded node is intra-frame prediction encoding and the sign of the azimuth residual of the previous encoded node is greater than a preset sign threshold; determine the azimuth context index based on a preset second index value when the previous encoded node is intra-frame prediction encoding and the sign of the azimuth residual of the previous encoded node is less than or equal to the preset sign threshold; determine the azimuth context index based on a preset third index value when the previous encoded node is inter-frame prediction encoding and the inter-frame prediction point used for encoding belongs to the first m candidate inter-frame prediction points corresponding to the previous encoded node; m is a positive integer not less than 1; determine the azimuth context index based on a preset fourth index value when the previous encoded node is inter-frame prediction encoding and the inter-frame prediction point used for encoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous encoded node; and determine the azimuth residual context corresponding to the current node based on the azimuth context index.

In some embodiments, the prediction residual includes: azimuth prediction residual; the residual coding context includes: azimuth residual context; the second encoding part 43 is also configured to determine the azimuth context index based on the parent node when the parent node is a head node and the current node is not a head node; and determine the azimuth residual context based on the azimuth context index.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; the second encoding part 43 is also configured to, when the parent node is a head node, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; the second encoding part 43 is also configured to determine, when the parent node is not a head node, at least one of a first radius context index, a second radius context index and a third radius context index according to a previous encoded node of the current node; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; the second encoding part 43 is also configured to, when the current node does not have a parent node, determine at least one of the first radius context index, the second radius context index and the third radius context index as a preset first flag value; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the second encoding part 43 is also configured to determine the first radius context index according to whether the previous encoded node adopts inter-frame prediction; and/or, determine the second radius context index according to whether the azimuth sampling interval of the previous encoded node is zero; and/or, determine the third radius context index according to whether the sign of the radius residual of the previous encoded node is less than a preset sign threshold.

In some embodiments, the prediction residual includes: a radius prediction residual; the residual coding context includes: a radius residual context; the second encoding part 43 is also configured to, when the parent node is a head node and the current node is not a head node, determine at least one of a first radius context index, a second radius context index and a third radius context index based on the parent node; based on at least one of the first radius context index, the second radius context index and the third radius context index, determine the radius residual context corresponding to the current node.

In some embodiments, the fourth prediction part 42 is further configured to perform inter-frame prediction on the current node according to the parent node. Predict, determine the inter-frame prediction value corresponding to the current node; determine the geometric prediction information of the current node based on the rate-distortion cost of the at least one intra-frame prediction value and the inter-frame prediction value; determine the prediction residual corresponding to the current node based on the geometric prediction information.

In some embodiments, the fourth prediction part 42 is also configured to determine, in the reference point cloud of the point cloud, an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; determine a first reference point and a second reference point on the same laser beam of the reference point cloud whose azimuths are greater than the azimuth of the initial reference point; and determine the inter-frame prediction value corresponding to the current node based on the first reference point and the second reference point.

In some embodiments, the second encoding part 43 is further configured to determine a preset initial value as the inter-frame flag coding context corresponding to the current node when the parent node is the head node in the prediction tree.

In some embodiments, the second encoding part 43 is also configured to determine the value of the inter-frame prediction flag of at least one encoded node before the current node as the inter-frame flag encoding context corresponding to the current node when the parent node is not the head node in the prediction tree.

In some embodiments, the second encoding part 43 is further configured to determine a preset initial value as the inter-frame flag decoding context corresponding to the current node when the current node does not have a parent node.

It should be noted that the description of the above device embodiment is similar to the description of the above method embodiment, and has similar beneficial effects as the method embodiment. For technical details not disclosed in the device embodiment of the present application, please refer to the description of the method embodiment of the present application for understanding.

In some embodiments, the embodiment of the present application further provides a decoder, and FIG17 is an optional structural diagram of the decoder 5 provided in the embodiment of the present application. As shown in FIG17, the decoder 5 includes: a first memory 52 and a first processor 53. Among them, the first memory 52 and the first processor 53 are connected through a first communication bus 54; the first memory 52 is used to store executable instructions; the first processor 53 is used to execute the executable instructions stored in the first memory 52, and implement the decoding method provided in the embodiment of the present application.

In some embodiments, the embodiment of the present application further provides an encoder, and FIG18 is an optional structural diagram of the encoder 6 provided in the embodiment of the present application. As shown in FIG18, the encoder 6 includes: a second memory 62 and a second processor 63. Among them, the second memory 62 and the second processor 63 are connected via a second communication bus 64; the second memory 62 is used to store executable instructions; the second processor 63 is used to execute the executable instructions stored in the second memory 62, and implement the encoding method provided in the embodiment of the present application.

An embodiment of the present application provides a computer-readable storage medium storing executable instructions, wherein executable instructions are stored. When the executable instructions are executed by a first processor, the first processor will be caused to execute any one of the decoding methods provided in the embodiments of the present application; or, when the executable instructions are executed by a second processor, the second processor will be caused to execute any one of the encoding methods provided in the embodiments of the present application.

In some embodiments, the computer-readable storage medium may be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, flash memory, magnetic surface storage, optical disk, or CD-ROM; or it may be various devices including one or any combination of the above memories.

In some embodiments, executable instructions may be in the form of a program, software, software module, script or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine or other unit suitable for use in a computing environment.

As an example, executable instructions may, but do not necessarily, correspond to a file in a file system, may be stored as part of a file that stores other programs or data, such as, for example, in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing one or more modules, subroutines, or code portions).

By way of example, executable instructions may be deployed to be executed on one computing device, or on multiple computing devices located at one site, or on multiple computing devices distributed across multiple sites and interconnected by a communication network.

Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of hardware embodiments, software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

The present application is described with reference to the flowcharts and/or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and/or box in the flowchart and/or block diagram, as well as the combination of the processes and/or boxes in the flowchart and/or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing one process or multiple processes in the flowchart and/or one block diagram. A device that performs the functions specified in a box or multiple boxes.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

The above is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the present application are included in the protection scope of the present application.

Industrial Applicability

The encoder/decoder can determine the prediction list corresponding to the current node according to the number of child nodes of the parent node of the current node, or according to the position of the parent node of the current node in the prediction tree, so that each laser beam in the point cloud can be encoded/decoded independently. The encoding/decoding of different laser beams does not affect each other and can be executed in parallel, thereby reducing the encoding and decoding delay, improving the encoding and decoding efficiency, and thus improving the encoding and decoding performance.

Furthermore, according to the number of child nodes of the parent node of the current node, or according to the position of the parent node of the current node in the prediction tree, the residual decoding context and/or inter-frame flag decoding context of the current node is determined, thereby further reducing inter-line dependency and improving encoding and decoding efficiency and encoding and decoding performance.

Claims (117)

A point cloud decoding method, applied to a decoder, comprising: Parse the bitstream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node; Determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree; Based on the prediction index and the current prediction list, an intra-frame prediction value corresponding to the current node is determined. The method according to claim 1, wherein the determining the current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, the preset prediction list is determined to be the current prediction list. The method according to claim 1, wherein the determining the current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, based on the reconstruction information of the previous decoded node of the current node, the prediction list corresponding to the previous decoded node is updated to determine the current prediction list. The method according to claim 1, wherein the method further comprises: When the current node has no parent node, a preset prediction list is determined to be the current prediction list. The method according to claim 2 or 4, wherein the prediction list comprises: at least one pair of prediction values, each pair of prediction values comprising: a radius prediction value and an azimuth prediction value, and the method further comprises: Using the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, The preset azimuth minimum value or the preset azimuth median value is used as the azimuth prediction value in the preset prediction list. The method according to claim 2 or 4, wherein the prediction list comprises: at least one pair of prediction values, each pair of prediction values comprising: a radius prediction value and an azimuth prediction value, and the method further comprises: According to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, at least one radius prediction value in the preset prediction list is determined in an incremental manner. The method according to claim 2 or 4, wherein the determining, based on the prediction index and the current prediction list, the intra prediction value corresponding to the current node comprises: When the number of child nodes of the current node is greater than or equal to the preset child node number threshold, the intra-frame prediction value corresponding to the current node is determined according to the number of decoded head nodes in the point cloud, the prediction index and the current prediction list. The method according to claim 2, wherein the determining, based on the prediction index and the current prediction list, the intra prediction value corresponding to the current node comprises: When the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, the intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node, the prediction index and the current prediction list. The method according to claim 3, wherein the determining, based on the prediction index and the current prediction list, the intra prediction value corresponding to the current node comprises: Based on the reconstruction information of the parent node, the prediction index and the current prediction list, an intra-frame prediction value corresponding to the current node is determined. The method according to claim 7, wherein the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining the intra-frame prediction value corresponding to the current node according to the number of decoded head nodes in the point cloud, the prediction index, and the current prediction list comprises: Determining the current beam prediction value according to the number of decoded head nodes in the point cloud; The current radius prediction value and the current azimuth prediction value are determined according to the prediction value corresponding to the prediction index in the current prediction list. The method according to claim 8 or 9, wherein the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; the determining the intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index, and the current prediction list includes: In a case where the prediction index corresponds to the first pair of prediction values in the current prediction list, determining the current beam prediction value, the current radius prediction value, and the current azimuth prediction value according to the parent node beam index reconstruction value, the parent node radius reconstruction value, and the parent node azimuth reconstruction value in the reconstruction information of the parent node; In the case where the prediction index corresponds to the nth pair of prediction values in the current prediction list, The radius prediction value is determined by using the radius prediction value of the current radius; n is an integer greater than 1; Determine the current azimuth prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value, and a preset azimuth sampling interval; The current beam prediction value is determined according to the parent node beam index reconstruction value. The method according to any one of claims 1 to 4, or any one of claims 8 to 10, wherein the method further comprises: Determine, based on the number of child nodes of the parent node, a residual decoding context and/or an inter-frame flag decoding context corresponding to the current node; Based on the residual decoding context, the prediction residual code corresponding to the current node is decoded, and/or, based on the inter-frame flag decoding context, the inter-frame prediction flag code corresponding to the current node is decoded to determine the prediction residual and/or inter-frame prediction flag corresponding to the current node; the prediction residual code and the inter-frame prediction flag code are obtained by bitstream parsing; When the inter-frame prediction flag indicates that the current node is not encoded using inter-frame prediction, geometric prediction information corresponding to the current node is determined based on the prediction residual and the intra-frame prediction value. The method according to claim 12, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual decoding context corresponding to the current node comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, the azimuth residual context is determined based on a preset fourth index value. The method according to claim 12, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual decoding context corresponding to the current node comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node. The method according to claim 12, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; the method further comprises: When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value. The method according to claim 14, wherein the determining the azimuth residual context corresponding to the current node based on a previous decoded node of the current node comprises: When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value; When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value; In a case where the previous decoded node is inter-frame prediction decoding, and the inter-frame prediction point used for decoding belongs to the first m candidate inter-frame prediction points corresponding to the previous decoded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1; When the previous decoded node is decoded by inter-frame prediction and the inter-frame prediction point used for decoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous decoded node, determining the azimuth context index based on a preset fourth index value; Based on the azimuth context index, determine the azimuth residual context corresponding to the current node. The method according to claim 12, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and based on the number of child nodes of the parent node, determining the residual decoding context corresponding to the current node comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine the azimuth context index based on the parent node; Based on the azimuth context index, the azimuth residual context is determined. The method according to claim 12, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; and determining the residual decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: In a case where the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index One, determine the radius residual context corresponding to the current node. The method according to claim 12, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; and determining the residual decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, determining at least one of a first radius context index, a second radius context index and a third radius context index according to a previous decoded node of the current node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 12, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises: In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 19, wherein the determining at least one of the first radius context index, the second radius context index, and the third radius context index according to the previous decoded node of the current node comprises at least one of the following: Determining the first radius context index according to whether the previous decoded node adopts inter-frame prediction; Determining the second radius context index according to whether the azimuth sampling interval of the previous decoded node is zero; The third radius context index is determined according to whether the sign of the radius residual of the previous decoded node is less than a preset sign threshold. The method according to claim 12, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; and determining the residual decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine at least one of the first radius context index, the second radius context index, and the third radius context index based on the parent node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 12, wherein the method further comprises: When the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, inter-frame prediction is performed on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node; Based on the prediction residual and the inter-frame prediction value, geometric prediction information corresponding to the current node is determined. The method according to claim 23, wherein the performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node comprises: In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point; Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined. The method according to claim 12, wherein determining the inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: In a case where the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node. The method according to claim 12, wherein determining the inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the value of the inter-frame prediction flag of at least one decoded node before the current node is determined as the inter-frame flag decoding context corresponding to the current node. The method according to claim 12, wherein the method further comprises: In the case that the current node does not have a parent node, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node. A point cloud encoding method, applied to an encoder, comprising: Determine the prediction tree corresponding to the point cloud; Determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree; Predicting the current node based on the current prediction list, and determining at least one intra-frame prediction value corresponding to the current node; Based on the at least one intra-frame prediction value, determine the geometric information encoding corresponding to the current node. The method according to claim 28, wherein determining the current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, the preset prediction list is determined to be the current prediction list. The method according to claim 28, wherein determining the current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the prediction list corresponding to the previous decoded node is updated based on the reconstruction information of the previous encoded node to determine the current prediction list. The method according to claim 28, wherein the method further comprises: When the current node has no parent node, a preset prediction list is determined to be the current prediction list. The method according to claim 29 or 31, wherein the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes: Using the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, The preset azimuth minimum value or the preset azimuth median value is used as the azimuth prediction value in the preset prediction list. The method according to claim 29 or 31, wherein the prediction list comprises: at least one pair of prediction values, each pair of prediction values comprising: a radius prediction value and an azimuth prediction value, and the method further comprises: According to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, at least one radius prediction value in the preset prediction list is determined in an incremental manner. The method according to claim 29 or 31, wherein the predicting the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node comprises: When the number of child nodes of the current node is greater than or equal to the preset child node number threshold, at least one intra-frame prediction value corresponding to the current node is determined according to the number of encoded head nodes in the point cloud and the current prediction list. The method according to claim 29, wherein the predicting the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node comprises: When the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, at least one intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node and the current prediction list. The method according to claim 30, wherein the predicting the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node comprises: At least one intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node and the current prediction list. The method according to claim 34, wherein each of the at least one intra-frame prediction value comprises: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining, according to the number of encoded head nodes in the point cloud and the current prediction list, at least one intra-frame prediction value corresponding to the current node comprises: Determining the current beam prediction value according to the number of decoded head nodes in the point cloud; At least one intra-frame prediction value corresponding to the current node is determined based on at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list and in combination with the current beam prediction value. The method according to claim 35 or 36, wherein each of the at least one intra-frame prediction value comprises: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list comprises: For a first intra-frame prediction value among the at least one intra-frame prediction value, determine a current radius prediction value, a current azimuth prediction value, and a current beam prediction value in the first intra-frame prediction value according to a parent node radius reconstruction value, a parent node azimuth reconstruction value, and a parent node beam index reconstruction value in the reconstruction information of the parent node; For an nth intra-frame prediction value in the at least one intra-frame prediction value, determine a current radius prediction value in the nth intra-frame prediction value according to the radius prediction value in the nth pair of prediction values in the current prediction list; n is an integer greater than 1; According to the azimuth prediction value in the nth pair of prediction values, the azimuth reconstruction value of the parent node and the preset azimuth sampling interval interval, determining a current azimuth prediction value in the n-th intra-frame prediction value; According to the parent node beam index reconstruction value, the current beam prediction value in the nth intra-frame prediction value is determined. The method according to any one of claims 28 to 31, or any one of claims 35 to 37, wherein the determining, based on the at least one intra-frame prediction value, the geometric information encoding corresponding to the current node comprises: Determining a prediction residual corresponding to the current node based on the at least one intra-frame prediction value; Determine, based on the number of child nodes of the parent node, a residual coding context and/or an inter-frame flag coding context corresponding to the current node; Based on the residual coding context, the prediction residual corresponding to the current node is encoded, and/or based on the inter-frame flag coding context, the inter-frame prediction flag corresponding to the current node is encoded, the prediction residual coding and/or inter-frame prediction flag coding corresponding to the current node are determined, and the geometric information coding is determined based on the prediction residual coding and/or inter-frame prediction flag coding. The method according to claim 39, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and determining the residual coding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, the azimuth residual context is determined based on a preset fourth index value. The method according to claim 39, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and determining the residual coding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node. The method according to claim 39, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and the method further comprises: When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value. The method according to claim 41, wherein the determining the azimuth residual context corresponding to the current node based on a previous encoded node of the current node comprises: When the previous coded node is intra-frame prediction coded and the sign of the azimuth residual of the previous coded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value; When the previous coded node is intra-prediction coded and the sign of the azimuth residual of the previous coded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value; In a case where the previous coded node is inter-frame prediction coded and the inter-frame prediction point used for coding belongs to the first m candidate inter-frame prediction points corresponding to the previous coded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1; When the previous encoded node is inter-frame prediction encoded, and the inter-frame prediction point used for encoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous encoded node, determining the azimuth context index based on a preset fourth index value; Based on the azimuth context index, determine the azimuth residual context corresponding to the current node. The method according to claim 39, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and determining the residual coding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine the azimuth context index based on the parent node; Based on the azimuth context index, the azimuth residual context is determined. The method according to claim 39, wherein the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; and determining the residual coding context corresponding to the current node based on the number of child nodes of the parent node comprises: In a case where the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 39, wherein the prediction residual comprises: a radius prediction residual; The following includes: a radius residual context; based on the number of child nodes of the parent node, determining a residual decoding context corresponding to the current node, including: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, determine at least one of a first radius context index, a second radius context index and a third radius context index according to a previous encoded node of the current node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 39, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises: In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 46, wherein the determining at least one of the first radius context index, the second radius context index, and the third radius context index based on a previous encoded node of the current node comprises at least one of the following: Determining the first radius context index according to whether the previous encoded node adopts inter-frame prediction; Determining the second radius context index according to whether the azimuth sampling interval of the previous encoded node is zero; The third radius context index is determined according to whether the sign of the radius residual of the previous encoded node is less than a preset sign threshold. The method according to claim 39, wherein the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; and determining the residual coding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, and the number of child nodes of the current node is less than the preset child node number threshold and greater than 0, determine at least one of the first radius context index, the second radius context index, and the third radius context index based on the parent node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 39, wherein the determining, based on the at least one intra-frame prediction value, the prediction residual corresponding to the current node comprises: Performing inter-frame prediction on the current node according to the parent node to determine an inter-frame prediction value corresponding to the current node; Determining geometric prediction information of the current node based on rate-distortion costs of the at least one intra-frame prediction value and the inter-frame prediction value; Based on the geometric prediction information, a prediction residual corresponding to the current node is determined. The method according to claim 50, wherein the performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node comprises: In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point; Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined. The method according to claim 39, wherein determining the inter-frame flag coding context corresponding to the current node based on the number of child nodes of the parent node comprises: In a case where the number of child nodes of the parent node is greater than or equal to a preset child node number threshold, a preset initial value is determined as the inter-frame flag coding context corresponding to the current node. The method according to claim 39, wherein determining the inter-frame flag decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the number of child nodes of the parent node is less than a preset child node number threshold and greater than 0, the value of the inter-frame prediction flag of at least one encoded node before the current node is determined as the inter-frame flag coding context corresponding to the current node. The method according to claim 39, wherein the method further comprises: When the current node does not have a parent node, the preset initial value is determined as the inter-frame flag bit corresponding to the current node. Decode context. A point cloud decoding method, applied to a decoder, comprising: Parse the bitstream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node; Determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree; Based on the prediction index and the current prediction list, an intra-frame prediction value corresponding to the current node is determined. The method according to claim 55, wherein determining the current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree comprises: In the case that the parent node is the head node, the preset prediction list is determined to be the current prediction list. The method according to claim 55, wherein determining the current prediction list corresponding to the current node according to the parent node corresponding to the current node in the prediction tree comprises: In the case where the parent node is not the head node in the prediction tree, based on the reconstruction information of the previous decoded node of the current node, the prediction list corresponding to the previous decoded node is updated to determine the current prediction list. The method according to claim 55, wherein the method further comprises: When the current node has no parent node, a preset prediction list is determined to be the current prediction list. The method according to claim 56 or 58, wherein the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes: Using the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, The preset azimuth minimum value or the preset azimuth median value is used as the azimuth prediction value in the preset prediction list. The method according to claim 56 or 58, wherein the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes: According to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, at least one radius prediction value in the preset prediction list is determined in an incremental manner. The method according to claim 56 or 58, wherein the determining, based on the prediction index and the current prediction list, the intra prediction value corresponding to the current node comprises: In the case where the current node is a head node, an intra-frame prediction value corresponding to the current node is determined according to the number of decoded head nodes in the point cloud, the prediction index and the current prediction list. The method according to claim 56, wherein the determining, based on the prediction index and the current prediction list, the intra prediction value corresponding to the current node comprises: When the current node is not a head node, an intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node, the prediction index and the current prediction list. The method according to claim 57, wherein the determining, based on the prediction index and the current prediction list, the intra prediction value corresponding to the current node comprises: Based on the reconstruction information of the parent node, the prediction index and the current prediction list, an intra-frame prediction value corresponding to the current node is determined. The method according to claim 61, wherein the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining the intra-frame prediction value corresponding to the current node according to the number of decoded head nodes in the point cloud, the prediction index, and the current prediction list comprises: Determining the current beam prediction value according to the number of decoded head nodes in the point cloud; The current radius prediction value and the current azimuth prediction value are determined according to the prediction value corresponding to the prediction index in the current prediction list. The method according to claim 62 or 63, wherein the intra-frame prediction value corresponding to the current node includes: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; the step of determining the geometric information prediction value corresponding to the current node based on the reconstruction information of the parent node, the prediction index, and the current prediction list includes: In a case where the prediction index corresponds to the first pair of prediction values in the current prediction list, determining the current beam prediction value, the current radius prediction value, and the current azimuth prediction value according to the parent node beam index reconstruction value, the parent node radius reconstruction value, and the parent node azimuth reconstruction value in the reconstruction information of the parent node; In a case where the prediction index corresponds to an nth pair of prediction values in the current prediction list, determining the current radius prediction value according to the radius prediction value in the nth pair of prediction values; n is an integer greater than 1; Determine the current azimuth prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value, and a preset azimuth sampling interval; The current beam prediction value is determined according to the parent node beam index reconstruction value. The method according to any one of claims 55 to 58, or any one of claims 62 to 64, wherein the method further comprises: Determine, based on the position of the parent node in the prediction tree, a residual decoding context and/or an inter-frame flag decoding context corresponding to the current node; Based on the residual decoding context, the prediction residual code corresponding to the current node is decoded, and/or, based on the inter-frame flag decoding context, the inter-frame prediction flag code corresponding to the current node is decoded to determine the prediction residual and/or inter-frame prediction flag corresponding to the current node; the prediction residual code and the inter-frame prediction flag code are obtained by bitstream parsing; When the inter-frame prediction flag indicates that the current node is not encoded using inter-frame prediction, geometric prediction information corresponding to the current node is determined based on the prediction residual and the intra-frame prediction value. The method according to claim 66, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and determining the residual decoding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is a head node, the azimuth residual context is determined based on a preset fourth index value. The method according to claim 66, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and determining the residual decoding context corresponding to the current node based on the number of child nodes of the parent node comprises: When the parent node is not a head node, an azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node. The method according to claim 66, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and the method further comprises: When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value. The method according to claim 68, wherein the determining the azimuth residual context corresponding to the current node based on a previous decoded node of the current node comprises: When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value; When the previous decoded node is intra-frame prediction decoding and the sign of the azimuth residual of the previous decoded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value; In a case where the previous decoded node is inter-frame prediction decoding, and the inter-frame prediction point used for decoding belongs to the first m candidate inter-frame prediction points corresponding to the previous decoded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1; In the case where the previous decoded node is inter-frame prediction decoding, and the inter-frame prediction point used for decoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous decoded node, based on the preset fourth index value azimuth context index; Based on the azimuth context index, determine the azimuth residual context corresponding to the current node. The method according to claim 66, wherein the prediction residual comprises: an azimuth prediction residual; the residual decoding context comprises: an azimuth residual context; and the method further comprises: When the parent node is a head node and the current node is not a head node, determining an azimuth context index based on the parent node; Based on the azimuth context index, the azimuth residual context is determined. The method of claim 66, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; and determining the residual decoding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: In a case where the parent node is a head node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method of claim 66, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; and determining the residual decoding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: In a case where the parent node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index according to a previous decoded node of the current node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method of claim 66, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises: In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method of claim 73, wherein the determining, based on a previous decoded node of the current node, at least one of the first radius context index, the second radius context index, and the third radius context index comprises at least one of the following: Determining the first radius context index according to whether the previous decoded node adopts inter-frame prediction; Determining the second radius context index according to whether the azimuth sampling interval of the previous decoded node is zero; The third radius context index is determined according to whether the sign of the radius residual of the previous decoded node is less than a preset sign threshold. The method of claim 66, wherein the prediction residual comprises: a radius prediction residual; the residual decoding context comprises: a radius residual context; the method further comprises: In a case where the parent node is a head node and the current node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index based on the parent node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 66, wherein the method further comprises: When the inter-frame prediction flag indicates that the current node adopts inter-frame prediction coding, inter-frame prediction is performed on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node; Based on the prediction residual and the inter-frame prediction value, geometric prediction information corresponding to the current node is determined. The method according to claim 66, wherein the performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node comprises: In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point; Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined. The method according to claim 66, wherein determining the inter-frame flag decoding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: In the case where the parent node is a head node, the preset initial value is determined as the inter-frame flag decoding context corresponding to the current node. The method according to claim 66, wherein determining the inter-frame flag decoding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is not a head node, the value of the inter-frame prediction flag of at least one decoded node before the current node is determined as the inter-frame flag decoding context corresponding to the current node. The method according to claim 66, wherein the method further comprises: In the case that the current node does not have a parent node, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node. A point cloud encoding method, applied to an encoder, comprising: Determine the prediction tree corresponding to the point cloud; Determine a current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree; Predicting the current node based on the current prediction list, and determining at least one intra-frame prediction value corresponding to the current node; Based on the at least one intra-frame prediction value, determine the geometric information encoding corresponding to the current node. The method according to claim 82, wherein determining the current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree comprises: In a case where the parent node is the head node in the prediction tree, a preset prediction list is determined to be the current prediction list. The method according to claim 82, wherein determining the current prediction list corresponding to the current node according to the position of the parent node of the current node in the prediction tree comprises: In the case that the parent node is not the head node, the prediction list corresponding to the previous decoded node is updated based on the reconstruction information of the previous encoded node to determine the current prediction list. The method according to claim 82, wherein the method further comprises: When the current node has no parent node, a preset prediction list is determined to be the current prediction list. The method according to claim 83 or 85, wherein the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes: Using the minimum radius value or the maximum radius value corresponding to the point cloud as the radius prediction value in the preset prediction list; and/or, The preset azimuth minimum value or the preset azimuth median value is used as the azimuth prediction value in the preset prediction list. The method according to claim 83 or 85, wherein the prediction list includes: at least one pair of prediction values, each pair of prediction values includes: a radius prediction value and an azimuth prediction value, and the method further includes: According to the geometric accuracy of the point cloud and based on the minimum radius corresponding to the point cloud, at least one radius prediction value in the preset prediction list is determined in an incremental manner. The method according to claim 83 or 85, wherein the predicting the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node comprises: In the case where the current node is a head node, at least one intra-frame prediction value corresponding to the current node is determined according to the number of encoded head nodes in the point cloud and the current prediction list. The method according to claim 83, wherein the predicting the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node comprises: When the current node is not a head node, at least one intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node and the current prediction list. The method according to claim 84, wherein the predicting the current node based on the current prediction list to determine at least one intra-frame prediction value corresponding to the current node comprises: At least one intra-frame prediction value corresponding to the current node is determined based on the reconstruction information of the parent node and the current prediction list. The method according to claim 88, wherein each of the at least one intra-frame prediction value comprises: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining, according to the number of encoded head nodes in the point cloud and the current prediction list, at least one intra-frame prediction value corresponding to the current node comprises: Determining the current beam prediction value according to the number of decoded head nodes in the point cloud; At least one intra-frame prediction value corresponding to the current node is determined based on at least one radius prediction value and at least one azimuth prediction value in at least one pair of prediction values in the current prediction list and in combination with the current beam prediction value. The method according to claim 89 or 90, wherein each of the at least one intra-frame prediction value comprises: a current beam prediction value, a current radius prediction value, and a current azimuth prediction value; and determining at least one intra-frame prediction value corresponding to the current node based on the reconstruction information of the parent node and the current prediction list comprises: For a first intra-frame prediction value among the at least one intra-frame prediction value, determine a current radius prediction value, a current azimuth prediction value, and a current beam prediction value in the first intra-frame prediction value according to a parent node radius reconstruction value, a parent node azimuth reconstruction value, and a parent node beam index reconstruction value in the reconstruction information of the parent node; For an nth intra-frame prediction value in the at least one intra-frame prediction value, determine a current radius prediction value in the nth intra-frame prediction value according to the radius prediction value in the nth pair of prediction values in the current prediction list; n is an integer greater than 1; Determine a current azimuth prediction value in the nth intra-frame prediction value according to the azimuth prediction value in the nth pair of prediction values, the parent node azimuth reconstruction value, and a preset azimuth sampling interval; According to the parent node beam index reconstruction value, the current beam prediction value in the nth intra-frame prediction value is determined. The method according to any one of claims 82 to 85, or any one of claims 89 to 91, wherein the determining, based on the at least one intra-frame prediction value, the geometric information encoding corresponding to the current node comprises: Determining a prediction residual corresponding to the current node based on the at least one intra-frame prediction value; Determine, based on the position of the parent node in the prediction tree, a residual coding context and/or an inter-frame flag coding context corresponding to the current node; Based on the residual coding context, the prediction residual corresponding to the current node is encoded, and/or based on the inter-frame flag coding context, the inter-frame prediction flag corresponding to the current node is encoded to determine the Prediction residual coding and/or inter-frame prediction flag coding are performed, and the geometric information coding is determined based on the prediction residual coding and/or inter-frame prediction flag coding. The method according to claim 93, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and determining the residual coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is a head node, the azimuth residual context is determined based on a preset fourth index value. The method according to claim 93, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and determining the residual coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is not a head node, an azimuth residual context corresponding to the current node is determined based on a previous decoded node of the current node. The method according to claim 93, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and the method further comprises: When the current node does not have a parent node, the azimuth residual context corresponding to the current node is determined based on a preset fourth index value. The method according to claim 95, wherein the determining the azimuth residual context corresponding to the current node based on a previous encoded node of the current node comprises: When the previous coded node is intra-frame prediction coded and the sign of the azimuth residual of the previous coded node is greater than a preset sign threshold, determining the azimuth context index based on a preset first index value; When the previous coded node is intra-prediction coded and the sign of the azimuth residual of the previous coded node is less than or equal to the preset sign threshold, determining the azimuth context index based on a preset second index value; In a case where the previous coded node is inter-frame prediction coded and the inter-frame prediction point used for coding belongs to the first m candidate inter-frame prediction points corresponding to the previous coded node, determining the azimuth context index based on a preset third index value; m is a positive integer not less than 1; When the previous encoded node is inter-frame prediction encoded, and the inter-frame prediction point used for encoding does not belong to the first m candidate inter-frame prediction points corresponding to the previous encoded node, determining the azimuth context index based on a preset fourth index value; Based on the azimuth context index, determine the azimuth residual context corresponding to the current node. The method according to claim 93, wherein the prediction residual comprises: an azimuth prediction residual; the residual coding context comprises: an azimuth residual context; and determining the residual coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is a head node and the current node is not a head node, determining an azimuth context index based on the parent node; Based on the azimuth context index, the azimuth residual context is determined. The method of claim 93, wherein the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; and determining the residual coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: In a case where the parent node is a head node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method of claim 93, wherein the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; and determining the residual coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index according to a previous encoded node of the current node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method of claim 93, wherein the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; the method further comprises: In a case where the current node does not have a parent node, determining at least one of the first radius context index, the second radius context index, and the third radius context index as a preset first flag value; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 100, wherein the determining, based on a previously encoded node of the current node, at least one of the first radius context index, the second radius context index, and the third radius context index comprises at least one of the following: Determining the first radius context index according to whether the previous encoded node adopts inter-frame prediction; Determining the second radius context index according to whether the azimuth sampling interval of the previous encoded node is zero; The third radius context index is determined according to whether the sign of the radius residual of the previous encoded node is less than a preset sign threshold. The method of claim 93, wherein the prediction residual comprises: a radius prediction residual; the residual coding context comprises: a radius residual context; and determining the residual coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is a head node and the current node is not a head node, determining at least one of a first radius context index, a second radius context index, and a third radius context index based on the parent node; Based on at least one of the first radius context index, the second radius context index, and the third radius context index, a radius residual context corresponding to the current node is determined. The method according to claim 93, wherein the determining, based on the at least one intra-frame prediction value, a prediction residual corresponding to the current node comprises: Performing inter-frame prediction on the current node according to the parent node to determine an inter-frame prediction value corresponding to the current node; Determining geometric prediction information of the current node based on rate-distortion costs of the at least one intra-frame prediction value and the inter-frame prediction value; Based on the geometric prediction information, a prediction residual corresponding to the current node is determined. The method according to claim 104, wherein the performing inter-frame prediction on the current node according to the parent node to determine the inter-frame prediction value corresponding to the current node comprises: In the reference point cloud of the point cloud, determining an initial reference point that is on the same laser beam as the parent node and has the same azimuth as the parent node; Determine, on the same laser beam of the reference point cloud, a first reference point and a second reference point whose azimuth angles are greater than the azimuth angle of the initial reference point; Based on the first reference point and the second reference point, an inter-frame prediction value corresponding to the current node is determined. The method according to claim 93, wherein determining the inter-frame flag coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: In the case where the parent node is the head node in the prediction tree, a preset initial value is determined as the inter-frame flag coding context corresponding to the current node. The method according to claim 93, wherein determining the inter-frame flag coding context corresponding to the current node based on the position of the parent node in the prediction tree comprises: When the parent node is not the head node in the prediction tree, the value of the inter-frame prediction flag of at least one coded node before the current node is determined as the inter-frame flag coding context corresponding to the current node. The method according to claim 93, wherein the method further comprises: In the case that the current node does not have a parent node, a preset initial value is determined as the inter-frame flag decoding context corresponding to the current node. A decoder, comprising: A first parsing part is configured to parse the bitstream to determine a prediction tree corresponding to the point cloud and a prediction index corresponding to the current node; A first determining part is configured to determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree; The first prediction part is configured to determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list. An encoder, comprising: A first construction part is configured to determine a prediction tree corresponding to the point cloud; A second determining part is configured to determine a current prediction list corresponding to the current node based on the number of child nodes of the parent node of the current node in the prediction tree; The second prediction part is configured to predict the current node based on the current prediction list and determine the current node corresponding at least one intra prediction value; The first encoding part is configured to determine the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value. A decoder, comprising: The second parsing part is configured to parse the code stream to determine the prediction tree corresponding to the point cloud and the prediction index corresponding to the current node; A third determining part is configured to determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree; The third prediction part is configured to determine the intra-frame prediction value corresponding to the current node based on the prediction index and the current prediction list. An encoder, comprising: A second construction part is configured to determine a prediction tree corresponding to the point cloud; A fourth determining part is configured to determine a current prediction list corresponding to the current node according to a position of a parent node of the current node in the prediction tree; A fourth prediction part is configured to predict the current node based on the current prediction list and determine at least one intra-frame prediction value corresponding to the current node; The second encoding part is configured to determine the geometric information encoding corresponding to the current node based on the at least one intra-frame prediction value. A decoder, comprising: a first memory and a first processor; The first memory stores a computer program executable on a first processor, and when the first processor executes the program, the method of any one of claims 1 to 27 or any one of claims 55 to 81 is implemented. An encoder, comprising: a second memory and a second processor; The second memory stores a computer program that can be run on the second processor, and when the second processor executes the program, it implements any one of claims 28 to 54, or any one of claims 82 to 108. A code stream, wherein the code stream is generated by bit encoding based on information to be encoded; wherein the information to be encoded includes geometric information encoding corresponding to a current node in a point cloud; the geometric information encoding is determined based on at least one intra-frame prediction value; the at least one intra-frame prediction value is determined by predicting the current node based on the current prediction list; the current prediction list is determined based on the number of child nodes of the parent node of the current node in a prediction tree. A code stream, wherein the code stream is generated by bit encoding based on information to be encoded; wherein the information to be encoded includes geometric information encoding corresponding to a current node in a point cloud; the geometric information encoding is determined based on at least one intra-frame prediction value; the at least one intra-frame prediction value is determined by predicting the current node based on the current prediction list; the current prediction list is determined based on the position of the parent node of the current node in the prediction tree. A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a first processor, the computer program implements the method described in any one of claims 1 to 27 or any one of claims 55 to 81; or, when the computer program is executed by a second processor, the computer program implements the method described in any one of claims 28 to 54 or any one of claims 82 to 108.