Method, apparatus, and medium for point cloud coding

Abstract

Conversion between a point group sequence and a bit stream of the point group sequence based on a set of syntax elements including at least one of: a first syntax element identifying a first point group frame, where a frame specific attribute property is applied to the first point group frame, and a bit length of the first syntax element is greater than or equal to the number of bits in a set of bits of a frame counter for a current point group frame in the point group sequence, the set of bits being indicated in the bit stream; or a second syntax element identifying a second point group frame, where a frame boundary marker is applied to the second point group frame, and a bit length of the second syntax element is greater than or equal to the number of bits in the set of bits.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to point cloud coding techniques, and more specifically to frame identification in geometry-based point cloud compression.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 63 / 292,206, filed December 21, 2021, the entire contents of which are incorporated herein by reference. [Background technology]

[0003] A point cloud is a collection of individual data points in a three-dimensional (3D) plane, with each point having set coordinates on the X, Y, and Z axes. Point clouds can therefore be used to represent the physical contents of a three-dimensional space. Point clouds have shown to be a promising way to represent 3D visual data for a wide range of immersive applications, from augmented reality to autonomous vehicles.

[0004] Point cloud coding standards have evolved primarily through the development of the well-known MPEG organization. MPEG stands for Moving Picture Experts Group and is one of the major standardization groups dealing with multimedia. In 2017, the MPEG 3D Graphics Coding Group (3DG) issued a Call for Proposals (CFP) document to initiate the development of a point cloud coding standard. The final standard will consist of two classes of solutions. Video-based point cloud compression (V-PCC or VPCC) is suitable for point sets with relatively uniform distribution of points. Geometry-based point cloud compression (G-PCC or GPCC) is suitable for more sparse distributions. However, the coding efficiency of conventional point cloud coding techniques is generally expected to be further improved. Summary of the Invention

[0005] The embodiments of the present disclosure provide a solution for point cloud coding.

[0006] In a first aspect, a method for point cloud coding is proposed, comprising: performing a conversion between a point cloud sequence and a bit stream of the point cloud sequence based on a set of syntax elements including at least one of: a first syntax element identifying a first point cloud frame in the point cloud sequence, a frame specific attribute property being applied to the first point cloud frame, a bit length of the first syntax element being equal to or greater than a number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream; or a second syntax element identifying a second point cloud frame in the point cloud sequence, a frame boundary marker being applied to the second point cloud frame, the bit length of the second syntax element being equal to or greater than a number of bits in the set of bits.

[0007] Based on the method according to the first aspect of the present disclosure, the bit length of the first or second syntax element is explicitly specified with respect to frame_ctr_lsb_bits. Compared with conventional solutions without such constraints, the proposed method has the advantage that it can improve the point cloud processing efficiency.

[0008] In a second aspect, an apparatus for processing point cloud data is proposed, the apparatus for processing point cloud data comprising a processor and a non-transitory memory with instructions that, when executed by the processor, cause the processor to perform a method according to the first aspect of the present disclosure.

[0009] In a third aspect, a non-transitory computer readable storage medium is proposed, said non-transitory computer readable storage medium storing instructions for causing a processor to perform the method according to the first aspect of the present disclosure.

[0010] In a fourth aspect, another non-transitory computer readable storage medium is proposed, the non-transitory computer readable storage medium storing a bit stream of a point cloud sequence generated by a method executed by a point cloud processing device, the method comprising: performing a conversion between the point cloud sequence and the bit stream based on a set of syntax elements including at least one of: a first syntax element identifying a first point cloud frame in the point cloud sequence, a frame specific attribute property is applied to the first point cloud frame, a bit length of the first syntax element is equal to or greater than the number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream; or a second syntax element identifying a second point cloud frame in the point cloud sequence, a frame boundary marker is applied to the second point cloud frame, the bit length of the second syntax element is equal to or greater than the number of bits in the set of bits.

[0011] In a fifth aspect, a method for storing a bit stream of a point cloud sequence is proposed, comprising: performing a conversion between the point cloud sequence and the bit stream based on a set of syntax elements including at least one of a first syntax element identifying a first point cloud frame in the point cloud sequence, a frame specific attribute property being applied to the first point cloud frame, a bit length of the first syntax element being equal to or greater than a number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream, or a second syntax element identifying a second point cloud frame in the point cloud sequence, a frame boundary marker being applied to the second point cloud frame, the bit length of the second syntax element being equal to or greater than a number of bits in the set of bits; and storing the bit stream in a non-transitory computer-readable recording medium.

[0012] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [Brief description of the drawings]

[0013] The above and other objects, features, and advantages of exemplary embodiments of the present disclosure will become more apparent through the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals generally refer to like components. [Figure 1] FIG. 1 is a block diagram illustrating an example point cloud coding system that may utilize techniques of this disclosure. [Diagram 2] FIG. 2 is a block diagram illustrating an example point cloud encoder, in accordance with some embodiments of the present disclosure. [Diagram 3] 1 is a block diagram illustrating an exemplary point cloud decoder in accordance with certain embodiments of the present disclosure. [Figure 4] 1 is a flowchart of a method for point cloud coding according to some embodiments of the present disclosure. [Diagram 5] FIG. 1 is a block diagram of a computing device capable of implementing various embodiments of the present disclosure.

[0014] Throughout the drawings, the same or similar reference numbers typically refer to the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, the principles of the present disclosure will be described with reference to some embodiments. It should be understood that these embodiments are provided for illustrative purposes only, to help those skilled in the art understand and embody the present disclosure, and do not imply any limitations on the scope of the present disclosure. The disclosure described herein can be embodied in various ways other than the methods described below.

[0016] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0017] References in this disclosure to "one embodiment," "one embodiment," "exemplary embodiment," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but do not necessarily mean that all embodiments include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, it is noted that when a particular feature, structure, or characteristic is described in connection with an exemplary embodiment, it is within the knowledge of one of ordinary skill in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly stated.

[0018] Terms such as "first" and "second" may be used herein to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0019] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. It will be further understood that the terms "comprise," "comprising," "having," "having," "containing," and / or "including," as used herein, specify the presence of stated features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0020] Example Environment FIG. 1 is a block diagram illustrating an example point cloud coding system 100 that may utilize techniques of this disclosure. As illustrated, the point cloud coding system 100 may include a source device 110 and a destination device 120. The source device 110 may also be referred to as a point cloud encoding device, and the destination device 120 may also be referred to as a point cloud decoding device. In operation, the source device 110 may be configured to generate encoded point cloud data. The destination device 120 may be configured to decode the encoded point cloud data generated by the source device 110. The techniques of this disclosure are generally directed to supporting coding (encoding and / or decoding) of point cloud data, i.e., point cloud compression. The coding may be effective to compress and / or decompress the point cloud data.

[0021] Source device 100 and destination device 120 may include any of a wide range of devices, including desktop computers, notebook (i.e., laptop) computers, tablet computers, set-top boxes, telephones such as smartphones and mobile phones, televisions, cameras, displays, digital media players, video game consoles, video streaming devices, vehicles (e.g., land or sea vehicles, spacecraft, aircraft, etc.), robots, LIDAR devices, satellites, augmented reality devices, etc. In some cases, source device 100 and destination device 120 may be equipped for wireless communication.

[0022] The source device 100 may include a data source 112, a memory 114, a GPCC encoder 116, and an input / output (I / O) interface 118. The destination device 120 may include an input / output (I / O) interface 128, a GPCC decoder 126, a memory 124, and a data consumer 122. In accordance with the present disclosure, the GPCC encoder 116 of the source device 100 and the GPCC decoder 126 of the destination device 120 may be configured to apply techniques of the present disclosure related to point cloud coding. Thus, the source device 100 represents an example of an encoding device, and the destination device 120 represents an example of a decoding device. In other examples, the source device 100 and the destination device 120 may include other components or arrangements. For example, the source device 100 may receive data (e.g., point cloud data) from an internal or external source. Similarly, the destination device 120 may interface with an external data consumer rather than including the data consumer in the same device.

[0023] In general, the data source 112 may represent a source of point cloud data (i.e., raw, unencoded point cloud data) and provide a continuous series of "frames" of point cloud data to the GPCC encoder 116, which encodes the frame point cloud data. In some examples, the data source 112 generates the point cloud data. The data source 112 of the source device 100 may include any of a variety of cameras or sensors, such as one or more video cameras, an archive containing previously captured point cloud data, a point cloud capture device such as a 3D scanner, or a light detection and ranging (LIDAR) device, and / or a data feed interface that receives point cloud data from a data content provider. Thus, in some examples, the data source 112 may generate the point cloud data based on signals from a LIDAR device. Alternatively or additionally, the point cloud data may be computer-generated from a scanner, camera, sensor, or other data. For example, the data source 112 may generate the point cloud data or a combination of live point cloud data, archived point cloud data, and computer-generated point cloud data. In either case, the GPCC encoder 116 encodes the captured, pre-captured, or computer-generated point cloud data. The GPCC encoder 116 may rearrange the frames of the point cloud data from the order in which they were received (sometimes referred to as "display order") into a coding order for coding. The GPCC encoder 116 may generate one or more bitstreams including the encoded point cloud data. The source device 100 may then output the encoded point cloud data via the I / O interface 118 for receipt and / or retrieval by, for example, the I / O interface 128 of the destination device 120. The encoded point cloud data may be transmitted directly to the destination device 120 via the I / O interface 118 over the network 130A. The encoded point cloud data may be stored on a storage medium / server 130B for access by the destination device 120.

[0024] The memory 114 of the source device 100 and the memory 124 of the destination device 120 may represent general purpose memories. In some examples, the memory 114 and the memory 124 may store raw point cloud data, e.g., raw point cloud data from the data source 112 and raw decoded point cloud data from the GPCC decoder 126. Additionally or alternatively, the memory 114 and the memory 124 may store software instructions executable by, e.g., the GPCC encoder 116 and the GPCC decoder 126, respectively. Although the memory 114 and the memory 124 are shown in this example as separate from the GPCC encoder 116 and the GPCC decoder 126, it should be understood that the GPCC encoder 116 and the GPCC decoder 126 may also include internal memory for functionally similar or equivalent purposes. Additionally, the memory 114 and the memory 124 may store encoded point cloud data, e.g., output from the GPCC encoder 116 and input to the GPCC decoder 126. In some examples, portions of memory 114 and memory 124 may be allocated as one or more buffers to store raw, decoded, and / or encoded point cloud data. For example, memory 114 and memory 124 may store point cloud data.

[0025] The I / O interface 118 and the I / O interface 128 may represent a wireless transmitter / receiver, a modem, a wired networking component (e.g., an Ethernet card), a wireless communication component operating according to any of the various IEEE 802.11 standards, or other physical components. In examples where the I / O interface 118 and the I / O interface 128 include wireless components, the I / O interface 118 and the I / O interface 128 may be configured to transfer data, such as encoded point cloud data, according to a cellular communication standard, such as 4G, 4G-LTE (Long Term Evolution), LTE-Advanced, 5G, etc. In some examples where the I / O interface 118 includes a wireless transmitter, the I / O interface 118 and the I / O interface 128 may be configured to transfer data, such as encoded point cloud data, according to other wireless standards, such as the IEEE 802.11 standard. In some examples, the source device 100 and / or the destination device 120 may include respective system-on-chip (SoC) devices. For example, source device 100 may include an SoC device that performs the functions attributed to GPCC encoder 116 and / or I / O interface 118. Destination device 120 may include an SoC device that performs the functions attributed to GPCC decoder 126 and / or I / O interface 128.

[0026] The techniques of this disclosure may be applied to encoding and decoding to support any of a variety of applications, such as communication between autonomous vehicles, communication between scanners, cameras, sensors, and processing device devices such as local or remote servers, geographic mapping, or other applications.

[0027] The I / O interface 128 of the destination device 120 receives the encoded bitstream from the source device 110. The encoded bitstream may include signaling information defined by the GPCC encoder 116, which is also used by the GPCC decoder 126, such as syntax elements having values ​​that represent the point cloud. The data consumer 122 uses the decoded data. For example, the data consumer 122 may use the decoded point cloud data to determine a location of a physical object. In some examples, the data consumer 122 may include a display that presents an image based on the point cloud data.

[0028] The GPCC encoder 116 and the GPCC decoder 126 may each be embodied as any of a variety of suitable encoder and / or decoder circuits, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, software, hardware, firmware, or combinations thereof. If the techniques are embodied in part in software, the device may store instructions of the software on a suitable non-transitory computer-readable medium and execute the instructions in hardware using one or more processors to perform the techniques of this disclosure. Each of the GPCC encoder 116 and the GPCC decoder 126 may be included in one or more encoders or decoders, any of which may be integrated as part of a combined encoder / decoder (CODEC) in the respective device. A device including the GPCC encoder 116 and / or the GPCC decoder 126 may include one or more integrated circuits, microprocessors, and / or other types of devices.

[0029] The GPCC encoder 116 and the GPCC decoder 126 may operate according to a coding standard, such as the Video Point Cloud Compression (VPCC) standard or the Geometry Point Cloud Compression (GPCC) standard. This disclosure may generally refer to coding (e.g., encoding and decoding) of frames, which includes the process of encoding or decoding data. The encoded bitstream generally includes a series of values ​​of syntax elements that represent coding decisions (e.g., coding modes).

[0030] A point cloud may include a set of points in 3D space. The points may have attributes associated with them. The attributes may be color information such as R, G, B, Y, Cb, Cr, or reflectance information, or other attributes. Point clouds may be captured by various cameras and sensors such as LIDAR sensors and 3D scanners, or may be computer generated. Point cloud data is used in various applications including, but not limited to, construction (modeling), graphics (3D models for visualization and animation), and automotive industries (LIDAR sensors used for navigation).

[0031] Figure 2 is a block diagram illustrating an example of a GPCC encoder 200, which may be an example of the GPCC encoder 116 in the system 100 shown in Figure 1, according to some embodiments of the present disclosure. Figure 3 is a block diagram illustrating an example of a GPCC decoder 300, which may be an example of the GPCC decoder 126 in the system 100 shown in Figure 1, according to some embodiments of the present disclosure.

[0032] In both GPCC Encoder 200 and GPCC Decoder 300, the point cloud location is coded first. The attribute coding depends on the decoded geometry. In Figures 2 and 3, the Region Adaptive Hierarchical Transformation (RAHT) unit 218, the Surface Approximation Analysis unit 212, the RAHT unit 314, and the Surface Approximation Synthesis unit 310 are options that are typically used for category 1 data. The Level of Detail (LOD) Generation unit 220, the Lifting unit 222, the LOD Generation unit 316, and the Inverse Lifting unit 318 are options that are typically used for category 3 data. All other units are common to categories 1 and 3.

[0033] For category 3 data, the compressed geometry is typically represented as an octree going from the root down to the leaf level of the individual voxels. For category 1 data, the compressed geometry is typically represented by a pruned octree (i.e. an octree going from the root down to the leaf level of blocks larger than a voxel) and a model approximating the surface in each leaf of the pruned octree. In this way, both category 1 and category 3 data share the octree coding mechanism, but category 1 data may additionally approximate the voxels in each leaf with a surface model. The surface model used is a triangulation with 1-10 triangles per block, resulting in a triangle soup. Category 1 geometry codecs are therefore known as Trisoup geometry codecs and category 3 geometry codecs are known as Octree geometry codecs.

[0034] In the example of FIG. 2, the GPCC encoder 200 may include a coordinate transformation unit 202, a color transformation unit 204, a voxelization unit 206, an attribute transfer unit 208, an octree analysis unit 210, a surface approximation analysis unit 212, an arithmetic encoding unit 214, a geometry reconstruction unit 216, a RAHT unit 218, an LOD generation unit 220, a lifting unit 222, a coefficient quantization unit 224, and an arithmetic encoding unit 226.

[0035] 2, the GPCC encoder 200 may receive a set of locations and a set of attributes. The locations may include coordinates of points in the point cloud. The attributes may include information about the points in the point cloud, such as a color associated with the points in the point cloud.

[0036] The coordinate transformation unit 202 may apply a transform to the coordinates of the points to convert the coordinates from an initial domain to a transformation domain. In this disclosure, the transformed coordinates may be referred to as transformed coordinates. The color transformation unit 204 may apply a transform to convert the color information of the attributes to a different domain. For example, the color transformation unit 204 may convert the color information from an RGB color space to a YCbCr color space.

[0037] Further, in the example of FIG. 2, the voxelization unit 206 may voxelize the transformed coordinates. Voxelizing the transformed coordinates may include quantizing and removing some points of the point cloud. In other words, multiple points of the point cloud may be contained within a single "voxel" and then treated as one point in some aspects. Further, the octree analysis unit 210 may generate an octree based on the voxelized transformed coordinates. Additionally, in the example of FIG. 2, the surface approximation analysis unit 212 may analyze the points to potentially determine a surface representation of the set of points. The arithmetic encoding unit 214 may perform arithmetic encoding on syntax elements representing the octree and / or surface information determined by the surface approximation analysis unit 212. The GPCC encoder 200 may output these syntax elements in a geometry bitstream.

[0038] The geometry reconstruction unit 216 may reconstruct transformation coordinates of points in the point cloud based on the octree, data indicative of the surface determined by the surface approximation analysis unit 212, and / or other information. The number of transformation coordinates reconstructed by the geometry reconstruction unit 216 may differ from the number of original points of the point cloud due to voxelization and surface approximation. In this disclosure, the resulting points may be referred to as reconstructed points. The attribute transfer unit 208 may transfer attributes of the original points of the point cloud to the reconstructed points of the point cloud data.

[0039] Further, the RAHT unit 218 may apply RAHT coding to the attributes of the reconstructed points. Alternatively or additionally, the LOD generation unit 220 and the lifting unit 222 may apply LOD processing and lifting, respectively, to the attributes of the reconstructed points. The RAHT unit 218 and the lifting unit 222 may generate coefficients based on the attributes. The coefficient quantization unit 224 may quantize the coefficients generated by the RAHT unit 218 or the lifting unit 222. The arithmetic encoding unit 226 may apply arithmetic coding to syntax elements representing the quantized coefficients. The GPCC encoder 200 may output these syntax elements in an attribute bitstream.

[0040] In the example of FIG. 3, the GPCC decoder 300 may include a geometry arithmetic decoding unit 302, an attribute arithmetic decoding unit 304, an octree synthesis unit 306, an inverse quantization unit 308, a surface approximation synthesis unit 310, a geometry reconstruction unit 312, a RAHT unit 314, an LOD generation unit 316, an inverse lifting unit 318, a coordinate inverse transformation unit 320, and a color inverse transformation unit 322.

[0041] The GPCC decoder 300 may obtain a geometry bitstream and an attribute bitstream. A geometry arithmetic decoding unit 302 of the decoder 300 may apply arithmetic decoding (e.g., CABAC or other types of arithmetic decoding) to syntax elements in the geometry bitstream. Similarly, an attribute arithmetic decoding unit 304 may apply arithmetic decoding to syntax elements in the attribute bitstream.

[0042] The octree synthesis unit 306 may synthesize an octree based on syntax elements parsed from the geometry bitstream. If surface approximation is used in the geometry bitstream, the surface approximation synthesis unit 310 may determine a surface model based on the syntax elements and octrees parsed from the geometry bitstream.

[0043] Further, the geometry reconstruction unit 312 may perform the reconstruction to determine coordinates of points in the point cloud. The coordinate inverse transformation unit 320 may apply an inverse transformation to the reconstructed coordinates to transform the reconstructed coordinates (positions) of the points in the point cloud from the transformed domain back to the initial domain.

[0044] Additionally, in the example of Figure 3, the inverse quantization unit 308 may inverse quantize the attribute value. The attribute value may be based on syntax elements obtained from the attribute bitstream (e.g., including syntax elements decoded by the attribute arithmetic decoding unit 304).

[0045] Depending on how the attribute values ​​are encoded, the RAHT unit 314 may perform RAHT coding to determine color values ​​for the points of the point cloud based on the dequantized attribute values. Alternatively, the LOD generation unit 316 and the inverse lifting unit 318 may use level-of-detail based techniques to determine color values ​​for the points of the point cloud.

[0046] 3, the color inverse transform unit 322 may apply an inverse color transform to the color values. The inverse color transform may be the inverse of the color transform applied by the color transform unit 204 of the encoder 200. For example, the color transform unit 204 may convert the color information from the RGB color space to the YCbCr color space. Thus, the color inverse transform unit 322 may convert the color information from the YCbCr color space to the RGB color space.

[0047] The various units in FIG. 2 and FIG. 3 are shown to aid in understanding the operations performed by the encoder 200 and the decoder 300. The units may be embodied as fixed function circuits, programmable circuits, or a combination thereof. A fixed function circuit refers to a circuit that provides a specific function and is preconfigured with respect to the operations that it can perform. A programmable circuit refers to a circuit that can be programmed to perform various tasks and provides flexible functionality in the operations that it can perform. For example, a programmable circuit may execute software or firmware that causes the programmable circuit to operate in a manner defined by the software or firmware instructions. Although a fixed function circuit may execute software instructions (e.g., to receive parameters or output parameters), the type of operations that a fixed function circuit performs are generally immutable. In some examples, one or more units may be separate circuit blocks (fixed function or programmable). In some examples, one or more units may be an integrated circuit.

[0048] Some exemplary embodiments of the present disclosure are described in detail below. Section headings are used herein for ease of understanding, and it should be understood that the embodiments disclosed in a section are not limited to only that section. Furthermore, although certain embodiments are described with reference to GPCC or other specific point cloud codecs, the disclosed techniques are also applicable to other point cloud coding techniques. Furthermore, although some embodiments describe point cloud coding steps in detail, it will be understood that the corresponding steps of decoding to undo the coding are embodied by a decoder. [Table 1] TIFF2025500437000003.tif252159TIFF2025500437000004.tif237160TIFF2025500437000005.tif253162TIFF20255004370 00006.tif250160TIFF2025500437000007.tif252160TIFF2025500437000008.tif251162TIFF2025500437000009.tif254161 TIFF2025500437000010.tif245162TIFF2025500437000011.tif254154TIFF2025500437000012.tif250160TIFF20255004370 00013.tif247162TIFF2025500437000014.tif248161TIFF2025500437000015.tif254161TIFF2025500437000016.tif179162

[0049] Further details of embodiments of the present disclosure related to frame identification in geometry-based point cloud compression are described below.

[0050] As used herein, the term "point cloud sequence" may refer to a sequence of zero or more point clouds. The term "point cloud frame" may refer to a point cloud in a point cloud sequence. The term "coded point cloud frame" may refer to a coded representation of a point cloud frame. The term "bounding box" may refer to an axis-aligned rectangular prism that defines a spatial region that bounds a set of points. The term "slice" may refer to a portion or an entire coded group frame that is composed of a geometry data unit (GDU) and zero or more corresponding attribute data units (ADUs).

[0051] 4 illustrates a flowchart of a method 400 for point cloud coding according to some embodiments of the present disclosure. As shown in FIG. 4, at 402, a conversion between a point cloud sequence and a bitstream of the point cloud sequence is performed based on a set of syntax elements. In some embodiments, the point cloud sequence may be encoded into the bitstream during the conversion at 402. Additionally or alternatively, the point cloud sequence may be decoded from the bitstream during the conversion at 402.

[0052] In some embodiments, the set of syntax elements includes a first syntax element that identifies a first point cloud frame in the point cloud sequence. Frame-specific attribute properties are applied to the first point cloud frame. In one example, the first syntax element may be syntax element fsap_frame_ctr_lsb. The bit length of the first syntax element is equal to or greater than the number of bits in the set of bits of a frame counter for a current point cloud frame in the point cloud sequence. The set of bits is indicated in the bitstream. In one example, the number of bits in the set of bits may be specified by a third syntax element, such as frame_ctr_lsb_bits. In one example, the bit length of syntax element fsap_frame_ctr_lsb may be specified to be equal to or greater than frame_ctr_lsb_bits.

[0053] Alternatively or additionally, the set of syntax elements includes a second syntax element that identifies a second point cloud frame in the point cloud sequence. A frame boundary marker is applied to the second point cloud frame. In one example, the second syntax element may be a syntax element fbdu_frame_ctr_lsb. The number of bits in the second syntax element is equal to or greater than the number of bits in the set of bits. In one example, the number of bits in the set of bits may be specified by a third syntax element, such as frame_ctr_lsb_bits. In one example, the bit length of the syntax element fbdu_frame_ctr_lsb may be specified to be equal to or greater than frame_ctr_lsb_bits.

[0054] Considering the above, the bit length of the first or second syntax element is explicitly specified in terms of frame_ctr_lsb_bits. Compared with conventional solutions without such constraints, the proposed method has the advantage of improving point cloud processing efficiency.

[0055] In some embodiments, the third syntax element may be included in a set of syntax elements. The third syntax element may be included in a sequence parameter set (SPS) that is activated for the point cloud sequence (also referred to as an active SPS).

[0056] In some additional embodiments, the set of syntax elements may further include a fourth syntax element that specifies a bit length of the first syntax element. By way of example and not limitation, the fourth syntax element may be syntax element fsap_frame_ctr_lsb_bits. In one example, the value of the fourth syntax element may be greater than or equal to the value of the third syntax element. The value of fsap_frame_ctr_lsb_bits may be specified to be greater than or equal to frame_ctr_lsb_bits in the active SPS. In another example, the value of the fourth syntax element may be equal to the value of the third syntax element. The value of fsap_frame_ctr_lsb_bits may be specified to be equal to frame_ctr_lsb_bits in the active SPS.

[0057] In some additional embodiments, the set of syntax elements may further include a fifth syntax element that specifies a bit length of the second syntax element. By way of example and not limitation, the fifth syntax element may be syntax element fbdu_frame_ctr_lsb_bits. In one example, the value of the fifth syntax element may be greater than or equal to the value of the third syntax element. The value of fbdu_frame_ctr_lsb_bits may be specified to be greater than or equal to the frame_ctr_lsb_bits in the active SPS. In another example, the value of the fifth syntax element may be equal to the value of the third syntax element. The value of fbdu_frame_ctr_lsb_bits may be specified to be equal to the frame_ctr_lsb_bits in the active SPS.

[0058] In some embodiments, the value of the third syntax element may be greater than 0. In one example, it may be specified that the value of frame_ctr_lsb_bits shall be greater than 0. In some embodiments, the current point cloud frame may include a slice. If the value of the third syntax element is greater than 0, a sixth syntax element indicating a set of bits (such as syntax element frame_ctr_lsb) may be included in a syntax structure for the geometry data unit header (such as geometry_data_unit_header( )) of the slice. In one example, the frame_ctr_lsb syntax element may be included in the geometry_data_unit_header( ) syntax structure based on a precondition "if(frame_ctr_lsb_bits>0)". In some embodiments, the value of the third syntax element may be equal to 0 and the bitstream shall include only one coded point cloud frame.

[0059] In some embodiments, the number of bits in the set of bits may be greater than 0, and the set of syntax elements further includes a seventh syntax element that specifies the number of bits in the set of bits minus 1. In one example, the seventh syntax element may be the syntax element frame_ctr_lsb_bits_minus1. It may be specified that frame_ctr_lsb_bits_minus1 plus 1 specifies the bit length of the frame_ctr_lsb syntax element.

[0060] In some embodiments, the current point cloud frame may include a slice. The set of syntax elements further includes an eighth syntax element (e.g., syntax element slice_tag_bits) that specifies a bit length of a slice tag for the slice. In one example, the value of the eighth syntax element may be greater than 0. It may be specified that the value of slice_tag_bits is greater than 0.

[0061] In some embodiments, if the value of the eighth syntax element is greater than 0, a ninth syntax element indicating a slice tag (such as the syntax element slice_tag) may be included in a syntax structure for the geometry data unit header (such as the geometry_data_unit_header( )) of said slice. In one example, the slice_tag syntax element may be included in the geometry_data_unit_header( ) syntax structure based on a precondition "if(slice_tag_bits>0)". Alternatively, the value of the eighth syntax element may be equal to 0 and the conversion may be performed without a tile inventory. As an example, if slice_tag_bits is equal to 0, it is specified that there shall be no tile inventory in the coded point cloud sequence.

[0062] In some embodiments, the current point cloud frame includes a slice. The number of bits in a slice tag for the slice may be greater than 0, and the set of syntax elements may further include a tenth syntax element that specifies a bit length of the slice tag minus 1. In one example, the tenth syntax element may be a syntax element slice_tag_bits_minus1. It may be specified that slice_tag_bits_minus1 plus 1 specifies a bit length of a slice_tag syntax element.

[0063] According to an embodiment of the present disclosure, a non-transitory computer-readable recording medium is proposed. A bit stream of a point cloud sequence is stored in the non-transitory computer-readable recording medium. The bit stream may be generated by a method executed by a point cloud processing device. According to the method, a conversion between a point cloud sequence and a bit stream of the point cloud sequence is performed based on a set of syntax elements. The set of syntax elements includes at least one of a first syntax element identifying a first point cloud frame in the point cloud sequence, a frame specific attribute property is applied to the first point cloud frame, a bit length of the first syntax element is equal to or greater than the number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream, or a second syntax element identifying a second point cloud frame in the point cloud sequence, a frame boundary marker is applied to the second point cloud frame, and a bit length of the second syntax element is equal to or greater than the number of bits in the set of bits.

[0064] According to an embodiment of the present disclosure, a method for storing a bit stream of a point cloud sequence is proposed, in which conversion between a point cloud sequence and a bit stream of the point cloud sequence is performed based on a set of syntax elements, the set of syntax elements including at least one of a first syntax element identifying a first point cloud frame in the point cloud sequence, a frame specific attribute property being applied to the first point cloud frame, a bit length of the first syntax element being equal to or greater than the number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream, or a second syntax element identifying a second point cloud frame in the point cloud sequence, a frame boundary marker being applied to the second point cloud frame, the bit length of the second syntax element being equal to or greater than the number of bits in the set of bits. The bit stream is stored in a non-transitory computer-readable recording medium.

[0065] Implementations of the present disclosure may be described in light of the following clauses: The features may be combined in any reasonable manner.

[0066] Clause 1. A method of point cloud coding, comprising: performing a conversion between a point cloud sequence and a bit stream of the point cloud sequence based on a set of syntax elements including at least one of: a first syntax element identifying a first point cloud frame in the point cloud sequence, where a frame specific attribute property is applied to the first point cloud frame, and a bit length of the first syntax element is greater than or equal to a number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream; or a second syntax element identifying a second point cloud frame in the point cloud sequence, where a frame boundary marker is applied to the second point cloud frame, and the bit length of the second syntax element is greater than or equal to the number of bits in the set of bits.

[0067] Clause 2. The method of clause 1, wherein the set of syntax elements further includes at least one of: a third syntax element specifying a number of bits in the set of bits; a fourth syntax element specifying a bit length of the first syntax element, the value of the fourth syntax element being greater than or equal to the value of the third syntax element; or a fifth syntax element specifying a bit length of the second syntax element, the value of the fifth syntax element being greater than or equal to the value of the third syntax element.

[0068] Clause 3. The method of clause 2, wherein the third syntax element is included in a sequence parameter set (SPS) activated for the point cloud sequence.

[0069] Clause 4. A method according to any one of clauses 2 to 3, wherein the first syntax element is represented as fsap_frame_ctr_lsb, the second syntax element is represented as fbdu_frame_ctr_lsb, the third syntax element is represented as frame_ctr_lsb_bits, the fourth syntax element is represented as fsap_frame_ctr_lsb_bits, or the fifth syntax element is represented as fbdu_frame_ctr_lsb_bits.

[0070] Clause 5. The method of any one of clauses 2 to 4, wherein the value of the third syntax element is greater than 0.

[0071] Clause 6. A method according to any one of clauses 2 to 4, wherein the current point cloud frame includes a slice, and if the value of the third syntax element is greater than 0, a sixth syntax element indicating the set of bits is included in a syntax structure for a geometry data unit header of the slice.

[0072] Clause 7. The method of clause 6, wherein the sixth syntax element is represented as frame_ctr_lsb.

[0073] Clause 8. The method of any one of clauses 2 to 4, wherein the value of the third syntax element is equal to 0 and the bitstream includes only one coded point cloud frame.

[0074] Clause 9. A method according to any one of clauses 1 to 4, wherein the number of bits in the set of bits is greater than 0, and the set of syntax elements further comprises a seventh syntax element specifying the number of bits in the set of bits minus 1.

[0075] Clause 10. The method of clause 9, wherein the seventh syntax element is represented as frame_ctr_lsb_bits_minus1.

[0076] Clause 11. A method according to any one of clauses 1 to 10, wherein the current point cloud frame includes a slice, and the set of syntax elements further includes an eighth syntax element that specifies a bit length of a slice tag for the slice.

[0077] Clause 12. The method of clause 11, wherein the eighth syntax element is represented as slice_tag_bits.

[0078] Clause 13. A method according to any one of clauses 11 to 12, wherein the value of the eighth syntax element is greater than 0.

[0079] Clause 14. A method according to any one of clauses 11 to 12, wherein if the value of the eighth syntax element is greater than 0, a ninth syntax element indicating the slice tag is included in a syntax structure for a geometry data unit header of the slice.

[0080] Clause 15. The method of clause 14, wherein the ninth syntax element is represented as slice_tag.

[0081] Clause 16. The method according to any one of clauses 11 to 12, wherein the value of the eighth syntax element is equal to 0 and the conversion is performed without a tile inventory.

[0082] Clause 17. A method according to any one of clauses 1 to 10, wherein the current point cloud frame includes a slice, a bit length of a slice tag for the slice is greater than 0, and the set of syntax elements further includes a tenth syntax element specifying a length that is one less than the bit length of the slice tag.

[0083] Clause 18. The method of clause 17, wherein the tenth syntax element is represented as slice_tag_bits_minus1.

[0084] Clause 19. The method of any one of clauses 1 to 18, wherein the converting comprises encoding the point cloud sequence into the bitstream.

[0085] Clause 20. A method according to any one of clauses 1 to 18, wherein the conversion comprises decoding the point cloud sequence from the bitstream.

[0086] Clause 21. An apparatus for processing point cloud data comprising a processor and a non-transitory memory having instructions which, when executed by the processor, cause the processor to perform a method according to any one of clauses 1 to 20.

[0087] Clause 22. A non-transitory computer-readable storage medium storing instructions that cause a processor to perform the method of any one of clauses 1 to 20.

[0088] Clause 23. A non-transitory computer readable recording medium storing a bit stream of a point cloud sequence generated by a method executed by a point cloud processing device, the method comprising the step of performing a conversion between the point cloud sequence and the bit stream based on a set of syntax elements including at least one of: a first syntax element identifying a first point cloud frame in the point cloud sequence, a frame specific attribute property being applied to the first point cloud frame, a bit length of the first syntax element being equal to or greater than the number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream; or a second syntax element identifying a second point cloud frame in the point cloud sequence, a frame boundary marker being applied to the second point cloud frame, the bit length of the second syntax element being equal to or greater than the number of bits in the set of bits.

[0089] Clause 24. A method for storing a bit stream of a point cloud sequence, comprising: performing a conversion between the point cloud sequence and the bit stream based on a set of syntax elements including at least one of: a first syntax element identifying a first point cloud frame in the point cloud sequence, where a frame specific attribute property is applied to the first point cloud frame, and a bit length of the first syntax element is greater than or equal to a number of bits in a set of bits of a frame counter for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bit stream; or a second syntax element identifying a second point cloud frame in the point cloud sequence, where a frame boundary marker is applied to the second point cloud frame, and the bit length of the second syntax element is greater than or equal to the number of bits in the set of bits; and storing the bit stream in a non-transitory computer-readable recording medium.

[0090] Exemplary Devices 5 illustrates a block diagram of a computing device 500 capable of implementing various embodiments of the present disclosure. The computing device 500 may be embodied as or included in the source device 110 (or the GPCC encoder 116 or 200) or the destination device 120 (or the GPCC decoder 126 or 300).

[0091] It will be appreciated that the computing device 500 illustrated in FIG. 5 is for illustrative purposes only and is not intended to suggest any limitation on the functionality and scope of the embodiments of the present disclosure.

[0092] 5, the computing device 500 includes a general purpose computing device 500. The computing device 500 may include at least one or more processors or processing units 510, a memory 520, a storage unit 530, one or more communication units 540, one or more input devices 550, and one or more output devices 560.

[0093] In some embodiments, the computing device 500 may be embodied as any user terminal or server terminal having computing capabilities. The server terminal may be a server provided by a service provider, a large-scale computing device, etc. The user terminal may be any type of mobile, fixed, or portable terminal, including, for example, a mobile phone, a station, a unit, a device, a multimedia computer, a multimedia tablet, an Internet node, a communicator, a desktop computer, a laptop computer, a notebook computer, a netbook computer, a tablet computer, a personal communication system (PCS) device, a personal navigation device, a personal digital assistant (PDA), an audio / video player, a digital camera / camcorder, a positioning device, a television receiver, a radio broadcast receiver, an electronic book device, a gaming device, or any combination thereof (including accessories and peripherals of these devices, or any combination thereof). It is contemplated that the computing device 500 may support any type of interface to a user, such as "wearable" circuitry.

[0094] The processing unit 510 may be a physical or virtual processor and may implement various processes based on programs stored in the memory 520. In a multiprocessor system, multiple processing units execute computer-executable instructions in parallel to increase the parallel processing capabilities of the computing device 500. The processing unit 510 may be referred to as a central processing unit (CPU), a microprocessor, a controller, or a microcontroller.

[0095] Computing device 500 typically includes a variety of computer storage media. Such media may be any media accessible by computing device 500, including, but not limited to, volatile and non-volatile media, or removable and non-removable media. Memory 520 may be volatile memory (e.g., registers, cache, random access memory (RAM)), non-volatile memory (e.g., read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory), or any combination thereof. Storage unit 530 may be any removable or non-removable media. And may include machine-readable media, such as memory, flash memory drives, magnetic disks, or other media that can be used to store information and / or data and that can be accessed by computing device 500.

[0096] The computing device 500 may further include additional removable / non-removable, volatile / non-volatile memory media. Although not shown in FIG. 5, it is possible to provide a magnetic disk drive that reads from and writes to a removable non-volatile magnetic disk, and an optical disk drive that reads from and writes to a removable non-volatile optical disk. In such a case, each drive may be connected to a bus (not shown) via one or more data media interfaces.

[0097] The communication unit 540 communicates with further computing devices via a communication medium. In addition, the functionality of the components in the computing device 500 may be embodied by a single computing cluster or multiple computing machines that can communicate via a communication connection. Thus, the computing device 500 can operate in a networked environment using logical connections with one or more other servers, networked personal computers (PCs), or further general network nodes.

[0098] The input device 550 may be one or more of various input devices such as a mouse, a keyboard, a tracking ball, a voice input device, etc. The output device 560 may be one or more of various output devices such as a display, a loudspeaker, a printer, etc. The communication unit 540 allows the computing device 500 to further communicate with one or more external devices (not shown), such as a storage device and a display device, one or more devices allowing a user to interact with the computing device 500, or any device (such as a network card, a modem, etc.) that allows the computing device 500 to communicate with one or more other computing devices, as needed. Such communication may be performed via an input / output (I / O) interface (not shown).

[0099] In some embodiments, instead of being integrated into a single device, some or all of the components of computing device 500 may be located in a cloud computing architecture. In a cloud computing architecture, the components may be provided remotely and work together to perform the functions described in this disclosure. In some embodiments, cloud computing provides computing, software, data access, and storage services without the end user needing to be aware of the physical location or configuration of the systems or hardware that provide these services. In various embodiments, cloud computing provides services over a wide area network (such as the Internet) using appropriate protocols. For example, a cloud computing provider provides applications over a wide area network that can be accessed through a web browser or other computing components. The software or components of the cloud computing architecture and corresponding data may be stored on servers in remote locations. Computing resources in a cloud computing environment may be consolidated or distributed at remote data center locations. A cloud computing infrastructure may act as a single access point for users but provide services through a shared data center. Thus, a cloud computing architecture may be used to provide the components and functions described herein from a service provider in a remote location. Alternatively, they may be provided from a conventional server or installed directly or otherwise on the client device.

[0100] The computing device 500 may be used to implement point cloud encoding / decoding in embodiments of the present disclosure. The memory 520 may include one or more point cloud coding modules 525 having one or more program instructions. These modules are accessible and executable by the processing unit 510 to perform the functions of various embodiments described herein.

[0101] In an example embodiment performing point cloud encoding, the input device 550 may receive point cloud data to be encoded as an input 570. The point cloud data may be processed, for example, by the point cloud coding module 525 to generate an encoded bitstream. The encoded bitstream may be provided as an output 580 via the output device 560.

[0102] In an example embodiment performing point cloud decoding, the input device 550 may receive an encoded bitstream as an input 570. The encoded bitstream may be processed, for example, by the point cloud coding module 525 to generate decoded point cloud data. The decoded point cloud data may be provided as output 580 via the output device 560.

[0103] Although the present disclosure has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present application as defined by the appended claims. Such variations are intended to be within the scope of the present application. Accordingly, the foregoing description of the embodiments of the present application is not intended to be limiting.

Claims

1. 1. A method of point cloud coding, comprising: a first syntax element that identifies a first point cloud frame in the point cloud sequence; A frame specific attribute property is applied to the first point cloud frame; a bit length of the first syntax element is greater than or equal to a number of bits in a set of frame counter bits for a current point cloud frame in the point cloud sequence; a first syntax element, the set of bits being indicated in a bitstream; or a second syntax element identifying a second point cloud frame within the point cloud sequence; A frame boundary marker is applied to the second point cloud frame; a second syntax element, the bit length of which is equal to or greater than the number of bits in the set of bits; performing a conversion between a point group sequence and a bitstream of said point group sequence based on a set of syntax elements comprising at least one of A method comprising:

2. the set of syntax elements further includes a third syntax element that specifies a number of bits in the set of bits; A fourth syntax element that specifies a bit length of the first syntax element, and the value of the fourth syntax element is equal to or greater than the value of the third syntax element; or a fifth syntax element that specifies a bit length of the second syntax element, the value of the fifth syntax element being equal to or greater than the value of the third syntax element; Further comprising at least one of: The method of claim 1.

3. The third syntax element is included in a sequence parameter set (SPS) activated for the point cloud sequence. The method of claim 2.

4. The first syntax element is represented as fsap_frame_ctr_lsb, The second syntax element is represented as fbdu_frame_ctr_lsb, The third syntax element is represented as frame_ctr_lsb_bits, The fourth syntax element is represented as fsap_frame_ctr_lsb_bits, or The fifth syntax element is represented as fbdu_frame_ctr_lsb_bits. The method according to any one of claims 2 to 3.

5. The value of the third syntax element is greater than 0. The method according to any one of claims 2 to 4.

6. the current point cloud frame includes a slice; If the value of the third syntax element is greater than 0, a sixth syntax element indicating the set of bits is included in a syntax structure for a geometry data unit header of the slice. The method according to any one of claims 2 to 4.

7. The sixth syntax element is represented as frame_ctr_lsb. The method according to claim 6.

8. the value of the third syntax element is equal to 0; the bitstream contains only one coded point cloud frame; The method according to any one of claims 2 to 4.

9. the number of bits in the set of bits is greater than 0; the set of syntax elements further includes a seventh syntax element that specifies the number of bits in the set of bits minus one. The method according to any one of claims 1 to 4.

10. The seventh syntax element is represented as frame_ctr_lsb_bits_minus1.

10. The method of claim 9.

11. the current point cloud frame includes a slice; The set of syntax elements further includes an eighth syntax element that specifies a bit length of a slice tag for the slice. The method according to any one of claims 1 to 10.

12. The eighth syntax element is represented as slice_tag_bits. The method of claim 11.

13. The value of the eighth syntax element is greater than 0. The method according to any one of claims 11 to 12.

14. If the value of the eighth syntax element is greater than 0, a ninth syntax element indicating the slice tag is included in a syntax structure for a geometry data unit header of the slice. The method according to any one of claims 11 to 12.

15. The ninth syntax element is represented as slice_tag. The method of claim 14.

16. the value of the eighth syntax element is equal to 0; The conversion is performed without a tile inventory. The method according to any one of claims 11 to 12.

17. the current point cloud frame includes a slice; the bit length of the slice tag for the slice is greater than 0; The set of syntax elements further includes a tenth syntax element that specifies a length that is one less than the bit length of the slice tag. The method according to any one of claims 1 to 10.

18. The tenth syntax element is represented as slice_tag_bits_minus1.

20. The method of claim 17.

19. the converting comprises encoding the point cloud sequence into the bitstream; 19. The method according to any one of claims 1 to 18.

20. the converting comprises decoding the point cloud sequence from the bitstream.

19. The method according to any one of claims 1 to 18.

21. 1. An apparatus for processing point cloud data, comprising a processor and a non-transitory memory with instructions, comprising: The instructions, when executed by the processor, cause the processor to perform a method according to any one of claims 1 to 20. Device.

22. storing instructions for causing a processor to carry out the method according to any one of claims 1 to 20; A non-transitory computer-readable storage medium.

23. A non-transitory computer readable recording medium storing a bit stream of a point cloud sequence generated by a method executed by a point cloud processing device, comprising: The method comprises: a first syntax element that identifies a first point cloud frame in the point cloud sequence; a first syntax element, where a frame specific attribute property is applied to the first point cloud frame, the bit length of the first syntax element being equal to or greater than the number of bits in a set of frame counter bits for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bitstream; or a second syntax element identifying a second point cloud frame within the point cloud sequence; a second syntax element, wherein a frame boundary marker is applied to the second point cloud frame, the second syntax element having a bit length greater than or equal to the number of bits in the set of bits; performing a conversion between the point cloud sequence and the bitstream based on a set of syntax elements including at least one of: A non-transitory computer-readable recording medium.

24. 1. A method for storing a bitstream of a point cloud sequence, comprising: a first syntax element that identifies a first point cloud frame in the point cloud sequence; a first syntax element, where a frame specific attribute property is applied to the first point cloud frame, the bit length of the first syntax element being equal to or greater than the number of bits in a set of frame counter bits for a current point cloud frame in the point cloud sequence, the set of bits being indicated in the bitstream; or a second syntax element identifying a second point cloud frame within the point cloud sequence; a second syntax element, wherein a frame boundary marker is applied to the second point cloud frame, the second syntax element having a bit length greater than or equal to the number of bits in the set of bits; performing a conversion between the point cloud sequence and the bitstream based on a set of syntax elements including at least one of: storing the bitstream on a non-transitory computer-readable recording medium; A method comprising:

Images