Method and apparatus for video encoding including two-dimensional image of compressed volumetric contents, method and apparatus for video decoding including two-dimensional image of compressed volumetric contents

Abstract

An embodiment of an apparatus is directed to improvements to dynamic mesh coding for SEI message for 2D snapshot image of compressed volumetric contents. The apparatus receives a compressed bitstream comprising information for a two-dimensional image from volumetric content, a processor decodes the compressed bitstream, generates a two-dimensional image and presents the two-dimensional image. Another embodiment of an apparatus is directed to dynamic mesh coding for 2D snapshot image track for V3C content. The apparatus receives a file comprising information for one or more two-dimensional images from volumetric content, a processor decodes the file, generates one or more two-dimensional image(s) and presents one or more two-dimensional image(s).

Description

METHOD AND APPARATUS FOR VIDEO ENCODING INCLUDING TWO-DIMENSIONAL IMAGE OF COMPRESSED VOLUMETRIC CONTENTS, METHOD AND APPARATUS FOR VIDEO DECODING INCLUDING TWO-DIMENSIONAL IMAGE OF COMPRESSED VOLUMETRIC CONTENTS

[0001] The disclosure relates to dynamic mesh coding, and more particularly to, for example, but not limited to, supplemental enhancement information (SEI) message for two-dimensional (2D) snapshot image of compressed volumetric contents and 2D snapshot image track for visual volumetric video-based coding (V3C) content.

[0002] Currently, Moving Picture Experts Group (MPEG) is working on compression of volumetric contents. Both Video-based Point Cloud Compression (V3C) and Video-based Dynamic Mesh Coding (V-DMC) compresses volumetric contents such as point clouds and mesh with various technologies including conventional video compression technology. The following are such technologies: the International Organization for Standardization and the International Electrotechnical Commission (ISO / IEC) 23090-5 Video-based Point Cloud Compression, ISO / IEC 23090-29 Video-based dynamic mesh coding (V-DMC), and ISO / IEC 23090-10 Carriage of Video-based Point Cloud Compression Data.

[0003] Both V3C and V-DMC compresses volumetric contents such as point clouds and mesh with various technologies including conventional video compression technology. Compressing volumetric contents has a strong benefit for saving resources for storage and delivery of the contents. However, it introduces a challenge for quick preview or trick play of the contents similar to the challenge any other compressed video data has. As one directional or bidirectional dependent coding could have been also applied to further enhance compression efficiency, more than one video frame should be decoded to get a specific frame of volumetric content. If random access points of the components are not aligned or the frame rates of the components are different than each other, a greater number of video frames should be decoded to get the result. So, quick preview or trick play of volumetric contents which used be a straightforward easy job for uncompressed volumetric contents has become quite a complicated resource and time-consuming process when the contents are compressed.

[0004] The description set forth in the background section should not be assumed to be prior art merely because it is set forth in the background section. The background section may describe aspects or embodiments of the present disclosure.

[0005] In some embodiments, this disclosure may relate to improvements to quick preview or trick play operations of volumetric contents.

[0006] In some embodiments, a two-dimensional (2D) snapshot image of volumetric contents is introduced. The 2D snapshot image of volumetric contents may eliminate the need to decode and render volumetric contents, reducing computational costs. The 2d snapshot images for volumetric contents may be carried in, for example but not limited to, supplemental enhancement information (SEI) messages or tracks.

[0007] An aspect of the disclosure provides an apparatus. The apparatus comprises a communication interface and a processor. The communication interface is configured to receive a compressed bitstream. The compressed bitstream comprises a coded volumetric frame and first image information for a first two-dimensional image corresponding to the coded volumetric frame. The processor is operably coupled to the communication interface. The processor is configured to decode the first image information to generate a first two-dimensional image and present the first two-dimensional image.

[0008] In some embodiments, the second image information comprises camera information for the second two-dimensional image. The camera information for the second two-dimensional image comprises a three-dimensional position and a directional vector of a camera used to generate the second two-dimensional image. The three-dimensional position and the directional vector of the camera used to generate the first two-dimensional image is different from the three-dimensional position and the directional vector of the camera used to generate the second two-dimensional image.

[0009] An aspect of the disclosure provides an apparatus. The apparatus comprises a communication interface and a processor. The communication interface is configured to receive a file comprising a first track and a second track. The first track includes one or more coded two-dimensional images corresponding to a coded volumetric frame. The second track includes atlas bitstream. The processor is operably coupled to the communication interface. The processor is configured to decode the one or more coded two-dimensional images to generate one or more two-dimensional images. The processor is configured to present the one or more two-dimensional images.

[0010] An aspect of the disclosure provides a method. The method is performed by an apparatus. The method comprises receiving a compressed bitstream. The compressed bitstream comprises a coded volumetric frame and image information for a two-dimensional image corresponding to the coded volumetric frame. The method further comprises decoding the image information to generate a two-dimensional image. The method further comprises presenting the two-dimensional image.

[0011] According to embodiments, while V3C requires decompression of large number of bitstreams, 2D snapshot images can be embodiments for quick preview or seeking use case of 3D Video-based Visual Volumetric Coding. Series of simple 2D images at certain points of time could be used as random access points to provide good overview of the contents.

[0012] FIG. 1 illustrates an example communication system 100 in accordance with an embodiment of this disclosure.

[0013] FIGS. 2 and 3 illustrate example electronic devices in accordance with an embodiment of this disclosure.

[0014] FIG. 4 illustrates a block diagram for an encoder encoding intra frames in accordance with an embodiment.

[0015] FIG. 5 illustrates a block diagram for a decoder in accordance with an embodiment.

[0016] FIG. 6 shows a basic block diagram of a 2D snapshot image SEI message processor in accordance with an embodiment of this disclosure.

[0017] FIG. 7 is a flowchart showing operations of the encoder in accordance with an embodiment.

[0018] FIG. 8 is a flowchart showing operations of the decoder in accordance with an embodiment.

[0019] FIG. 9 is a flowchart showing operations of the encoder in accordance with another embodiment.

[0020] FIG. 10 is a flowchart showing operations of the decoder in accordance with another embodiment.

[0021] FIG. 11 is a flowchart showing operations of the decoder in accordance with another embodiment.

[0022] FIG. 12 is a flowchart showing operations of the encoder in accordance with another embodiment.

[0023] In one or more implementations, not all of the depicted components in each figure may be required, and one or more implementations may include additional components not shown in a figure. Variations in the arrangement and type of the components may be made without departing from the scope of the subject disclosure. Additional components, different components, or fewer components may be utilized within the scope of the subject disclosure.

[0024] In some embodiments, a two-dimensional (2D) snapshot image of volumetric contents is introduced. The 2D snapshot image of volumetric contents may eliminate the need to decode and render volumetric contents, reducing computational costs. The 2d snapshot images for volumetric contents may be carried in, for example but not limited to, supplemental enhancement information (SEI) messages or tracks.

[0025] An aspect of the disclosure provides an apparatus for video decoding. The apparatus comprises a communication interface and a processor. The communication interface is configured to receive a compressed bitstream. The compressed bitstream comprises a coded volumetric frame and first image information for a first two-dimensional image corresponding to the coded volumetric frame. The processor is operably coupled to the communication interface. The processor is configured to decode the first image information to generate a first two-dimensional image and present the first two-dimensional image.

[0026] In some embodiments, the first image information is followed by the coded volumetric frame in the compressed bitstream.

[0027] In some embodiments, the first image information is provided by a supplemental enhancement information (SEI) message in the compressed bitstream.

[0028] In some embodiments, the first image information includes a flag indicating whether the first image information comprises camera information about a camera used to generate the first two-dimensional image.

[0029] In some embodiments, when the flag indicates that the first image information comprises the camera information, the first image information further comprises the camera information containing for a three-dimensional position and a directional vector of a camera used to generate the first two-dimensional image.

[0030] In some embodiments, the compressed bitstream comprises a second image information for a second two-dimensional image. The processor is further configured to decode the second image information to generate the second two-dimensional image. The processor is further configured to present the second two-dimensional image.

[0031] In some embodiments, the second image information comprises camera information for the second two-dimensional image. The camera information for the second two-dimensional image comprises a three-dimensional position and a directional vector of a camera used to generate the second two-dimensional image. The three-dimensional position and the directional vector of the camera used to generate the first two-dimensional image is different from the three-dimensional position and the directional vector of the camera used to generate the second two-dimensional image.

[0032] An aspect of the disclosure provides an apparatus. The apparatus comprises a communication interface and a processor. The communication interface is configured to receive a file comprising a first track and a second track. The first track includes one or more coded two-dimensional images corresponding to a coded volumetric frame. The second track includes atlas bitstream. The processor is operably coupled to the communication interface. The processor is configured to decode the one or more coded two-dimensional images to generate one or more two-dimensional images. The processor is configured to present the one or more two-dimensional images.

[0033] In some embodiments, the second track references a volumetric track including volumetric data.

[0034] In some embodiments, the second track further comprises one or more identifiers which designate tracks containing two-dimensional images which the second track references.

[0035] In some embodiments, the one or more coded two-dimensional images are sync samples.

[0036] In some embodiments, the file further comprises a third track including camera information about a camera used to generate the one or more two-dimensional images.

[0037] In some embodiments, the third track includes a viewport sample and the viewport sample whose composition time is same with a snapshot image provides information about a camera used to render the snapshot image.

[0038] An aspect of the disclosure provides a method. The method is performed by an apparatus. The method comprises receiving a compressed bitstream. The compressed bitstream comprises a coded volumetric frame and image information for a two-dimensional image corresponding to the coded volumetric frame. The method further comprises decoding the image information to generate a two-dimensional image. The method further comprises presenting the two-dimensional image.

[0039] In some embodiments, the image information is followed by the coded volumetric frame in the compressed bitstream.

[0040] In some embodiments, the image information is provided by a supplemental enhancement information (SEI) message in the compressed bitstream.

[0041] In some embodiments, the image information includes a flag indicating whether the image information comprises camera information about a camera used to generate the first two-dimensional image.

[0042] In some embodiments, when the flag indicates that the image information comprises the camera information, the image information further comprises the camera information containing for a three-dimensional position and a directional vector of a camera used to generate the first two-dimensional image.

[0043] In some embodiments, the compressed bitstream comprises image information for a second two-dimensional image. The method further comprises decoding the image information to generate the second two-dimensional image. The method further comprises presenting the second two-dimensional image.

[0044] In some embodiments, the image information comprises camera information for the first two-dimensional image and the second two-dimensional image. The camera information comprises a three-dimensional position and a directional vector of a camera used to generate the first two-dimensional image and the second two-dimensional image, wherein the three-dimensional position and the directional vector of the camera used to generate the first two-dimensional image is different from the three-dimensional position and the directional vector of the camera used to generate the second two-dimensional image.

[0045] An aspect of the disclosure provides an apparatus. The apparatus comprises a communication interface and a processor. The communication interface is configured to receive a bitstream comprising a coded volumetric frame, coded data of a two-dimensional image corresponding to the coded volumetric frame, and image information for the two-dimensional image. The processor is operably coupled to the communication interface. The processor is configured to decode the coded data to reconstruct the two-dimensional image corresponding to the coded volumetric frame, and decode the image information to be used to present the two-dimensional image. The image information includes information on a codec used for decoding the two-dimensional image and information on a size of the two-dimensional image, and information on a size of the coded data. The image information and the coded data are provided by a supplemental enhancement information (SEI) message in the bitstream.

[0046] In some embodiments, the image information is followed by the coded volumetric frame in the bitstream.

[0047] In some embodiments, the processor configured to present the two-dimensional image using the image information.

[0048] In some embodiments, the image information includes a flag indicating whether the image information comprises camera information about a camera used to render the two-dimensional image in a camera location.

[0049] In some embodiments, when the flag indicates that the image information comprises the camera information, the image information further comprises the camera information containing for a three-dimensional position and a directional vector of a camera used to render the two-dimensional image in the camera location.

[0050] An aspect of the disclosure provides a method. The method is performed by an apparatus for encoding video. The method comprises encoding a volumetric frame to generate a coded volumetric frame and encoding two-dimensional image corresponding to the coded volumetric frame to generate coded data of a two-dimensional image, and determining image information to be used to render the two-dimensional image. The method further comprises generating a bitstream including the coded volumetric frame, the coded data of the two-dimensional image, and the image information for the two-dimensional image. The image information includes information on a codec used for decoding the two-dimensional image and information on a size of the two-dimensional image, and information on a size of the coded data. The image information and the coded data are included in a supplemental enhancement information (SEI) message in the bitstream.

[0051] In some embodiments, the image information includes a flag indicating whether the image information comprises camera information about a camera used to render the first two-dimensional image in a camera location.

[0052] In some embodiments, when the flag indicates that the image information comprises the camera information, the image information further comprises the camera information containing for a three-dimensional position and a directional vector of a camera used to render the two-dimensional image in the camera location.

[0053] The detailed description set forth below, in connection with the appended drawings, is intended as a description of various implementations and is not intended to represent the only implementations in which the subject technology may be practiced. Rather, the detailed description includes specific details for the purpose of providing a thorough understanding of the inventive subject matter. As those skilled in the art would realize, the described implementations may be modified in various ways, all without departing from the scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements.

[0054] Three hundred sixty degree (360°) video and 3D volumetric video are emerging as new ways of experiencing immersive content due to the ready availability of powerful handheld devices such as smartphones. While 360°　video enables immersive "real life," "being there" experience for consumers by capturing the 360°　outside-in view of the world, 3D volumetric video can provide complete six degrees of freedom (6DoF) experience of being and moving within the content. Users can interactively change their viewpoint and dynamically view any part of the captured scene or object they desire. Display and navigation sensors can track head movement of the user in real-time to determine the region of the 360°　video or volumetric content that the user wants to view or interact with. Multimedia data that is three-dimensional (3D) in nature, such as point clouds or 3D polygonal meshes, can be used in the immersive environment.

[0055] A point cloud is a set of 3D points along with attributes such as color, normal, reflectivity, point-size, etc. that represent an object's surface or volume. Point clouds are common in a variety of applications such as gaming, 3D maps, visualizations, medical applications, augmented reality, virtual reality, autonomous driving, multi-view replay, 6DoF immersive media, to name a few. Point clouds, if uncompressed, generally require a large amount of bandwidth for transmission. Due to the large bitrate requirement, point clouds are often compressed prior to transmission. To compress a 3D object such as a point cloud, often requires specialized hardware. To avoid specialized hardware to compress a 3D point cloud, a 3D point cloud can be transformed into traditional two-dimensional (2D) frames and that can be compressed and later be reconstructed and viewable to a user.

[0056] Polygonal 3D meshes, especially triangular meshes, are another popular format for representing 3D objects. Meshes typically consist of a set of vertices, edges and faces that are used for representing the surface of 3D objects. Triangular meshes are simple polygonal meshes in which the faces are simple triangles covering the surface of the 3D object. Typically, there may be one or more attributes associated with the mesh. In one scenario, one or more attributes may be associated with each vertex in the mesh. For example, a texture attribute (RGB) may be associated with each vertex. In another scenario, each vertex may be associated with a pair of coordinates, (u,　v). The (u,　v) coordinates may point to a position in a texture map associated with the mesh. For example, the (u,　v) coordinates may refer to row and column indices in the texture map, respectively. A mesh can be thought of as a point cloud with additional connectivity information.

[0057] The point cloud or meshes may be dynamic, i.e., they may vary with time. In these cases, the point cloud or mesh at a particular time instant may be referred to as a point cloud frame or a mesh frame, respectively.

[0058] Since point clouds and meshes contain a large amount of data, they require compression for efficient storage and transmission. This is particularly true for dynamic point clouds and meshes, which may contain 60 frames or higher per second.

[0059] Figures discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably-arranged system or device.

[0060] FIG. 1 illustrates an example communication system 100 in accordance with an embodiment of this disclosure. The embodiment of the communication system 100 shown in FIG.　1 is for illustration only. Other embodiments of the communication system 100 can be used without departing from the scope of this disclosure.

[0061] The communication system　100 may include a network　102 that facilitates communication between various components in the communication system　100. For example, the network　102 may communicate IP packets, frame relay frames, Asynchronous Transfer Mode (ATM) cells, or other information between network addresses. The network　102 may include one or more local area networks (LANs), metropolitan area networks (MANs), wide area networks (WANs), all or a portion of a global network such as the Internet, or any other communication system or systems at one or more locations.

[0062] In this example, the network　102 may facilitate communications between a server 104 and various client devices 106-116. The client devices 106-116 may be, for example, a smartphone, a tablet computer, a laptop, a personal computer, a TV, an interactive display, a wearable device, a HMD, or the like. The server　104 can represent one or more servers. Each server　104 may include any suitable computing or processing device that can provide computing services for one or more client devices, such as the client devices 106-116. Each server　104 may, for example, include one or more processing devices, one or more memories storing instructions and data, and one or more network interfaces facilitating communication over the network　102. As described in more detail below, the server 104 may transmit a compressed bitstream, representing a point cloud or mesh, to one or more display devices, such as a client device 106-116. In certain embodiments, each server 104 may include an encoder.

[0063] Each client device　106-116 may represent any suitable computing or processing device that interacts with at least one server (such as the server 104) or other computing device(s) over the network　102. The client devices 106-116 may include a desktop computer　106, a mobile telephone or mobile device　108 (such as a smartphone), a PDA　110, a laptop computer　112, a tablet computer　114, and a HMD 116. However, any other or additional client devices may be used in the communication system　100. Smartphones may represent a class of mobile devices 108 that are handheld devices with mobile operating systems and integrated mobile broadband cellular network connections for voice, short message service (SMS), and Internet data communications. The HMD　116 may display　360° scenes including one or more dynamic or static 3D　point clouds. In certain embodiments, any of the client devices　106-116 may include an encoder, decoder, or both. For example, the mobile device　108 may record a 3D volumetric video and then encode the video enabling the video to be transmitted to one of the client devices　106-116. In another example, the laptop computer　112 may be used to generate a 3D point cloud or mesh, which is then encoded and transmitted to one of the client devices　106-116.

[0064] In this example, some client devices 108-116 may communicate indirectly with the network 102. For example, the mobile device 108 and PDA　110 may communicate via one or more base stations 118, such as cellular base stations or eNodeBs (eNBs). Also, the laptop computer　112, the tablet computer　114, and the HMD 116 may communicate via one or more wireless access points　120, such as IEEE 802.11 wireless access points. Note that these are for illustration only and that each client device　106-116 may communicate directly with the network 102 or indirectly with the network　102 via any suitable intermediate device(s) or network(s). In certain embodiments, the server 104 or any client device 106-116 may be used to compress a point cloud or mesh, generate a bitstream that represents the point cloud or mesh, and transmit the bitstream to another client device such as any client device 106-116.

[0065] In certain embodiments, any of the client devices 106-114 may transmit information securely and efficiently to another device, such as, for example, the server 104. Also, any of the client devices 106-116 may trigger the information transmission between itself and the server 104. Any of the client devices 106-114 may function as a VR display when attached to a headset via brackets, and function similar to HMD　116. For example, the mobile device 108 when attached to a bracket system and worn over the eyes of a user may function similarly as the HMD 116. The mobile device　108 (or any other client device 106-116) may trigger the information transmission between itself and the server 104.

[0066] In certain embodiments, any of the client devices　106-116 or the server 104 may create a 3D point cloud or mesh, compress a 3D point cloud or mesh, transmit a 3D point cloud or mesh, receive a 3D point cloud or mesh, decode a 3D point cloud or mesh, render a 3D point cloud or mesh, or a combination thereof. For example, the server 104 may then compress 3D point cloud or mesh to generate a bitstream and then transmit the bitstream to one or more of the client devices　106-116. For another example, one of the client devices 106-116 may compress a 3D point cloud or mesh to generate a bitstream and then transmit the bitstream to another one of the client devices 106-116 or to the server 104.

[0067] Although FIG.　1 illustrates one example of a communication system　100, various changes may be made to FIG.　1. For example, the communication system　100 may include any number of each component in any suitable arrangement. In general, computing and communication systems may come in a wide variety of configurations, and FIG.　1 does not limit the scope of this disclosure to any particular configuration. While FIG.　1 illustrates one operational environment in which various features can be used, these features may be used in any other suitable system.

[0068] FIGS. 2 and 3 illustrate example electronic devices in accordance with an embodiment of this disclosure. In particular, FIG. 2 illustrates an example server 200, and the server　200 may represent the server 104 in FIG. 1. The server 200 may represent one or more encoders, decoders, local servers, remote servers, clustered computers, and components that act as a single pool of seamless resources, a cloud-based server, and the like. The server 200 may be accessed by one or more of the client devices 106-116 of FIG. 1 or another server.

[0069] The server 200 may represent one or more local servers, one or more compression servers, or one or more encoding servers, such as an encoder. In certain embodiments, the encoder may perform decoding. As shown in FIG. 2, the server　200 may include a bus system 205 that supports communication between at least one processing device (such as a processor 210), at least one storage device 215, at least one communications interface　220, and at least one input / output (I / O) unit 225.

[0070] The processor 210 may execute instructions that can be stored in a memory　230. The processor　210 may include any suitable number(s) and type(s) of processors or other devices in any suitable arrangement. Example types of processors　210 may include microprocessors, microcontrollers, digital signal processors, field programmable gate arrays, application specific integrated circuits, and discrete circuitry.

[0071] In certain embodiments, the processor 210 may encode a 3D point cloud or mesh stored within the storage devices 215. In certain embodiments, encoding a 3D point cloud may also decodes the 3D point cloud or mesh to ensure that when the point cloud or mesh is reconstructed, the reconstructed 3D point cloud or mesh may match the 3D point cloud or mesh prior to the encoding.

[0072] The memory 230 and a persistent storage 235 may be examples of storage devices　215 that represent any structure(s) capable of storing and facilitating retrieval of information (such as data, program code, or other suitable information on a temporary or permanent basis). The memory　230 may represent a random access memory or any other suitable volatile or non-volatile storage device(s). For example, the instructions stored in the memory 230 may include instructions for decomposing a point cloud into patches, instructions for packing the patches on　2D frames, instructions for compressing the 2D frames, as well as instructions for encoding　2D frames in a certain order in order to generate a bitstream. The instructions stored in the memory　230 may also include instructions for rendering the point cloud on an omnidirectional　360° scene, as viewed through a VR headset, such as HMD 116 of FIG. 1. The persistent storage 235 may contain one or more components or devices supporting longer-term storage of data, such as a read only memory, hard drive, Flash memory, or optical disc.

[0073] The communications interface 220 may support communications with other systems or devices. For example, the communications interface 220 may include a network interface card or a wireless transceiver facilitating communications over the network 102 of FIG. 1. The communications interface　220 may support communications through any suitable physical or wireless communication link(s). For example, the communications interface　220 may transmit a bitstream containing a 3D point cloud to another device such as one of the client devices　106-116.

[0074] The I / O unit 225 may allow for input and output of data. For example, the I / O unit　225 may provide a connection for user input through a keyboard, mouse, keypad, touchscreen, or other suitable input device. The I / O unit 225 may also send output to a display, printer, or other suitable output device. Note, however, that the I / O unit 225 may be omitted, such as when I / O interactions with the server 200 occur via a network connection.

[0075] Note that while FIG. 2 is described as representing the server 104 of FIG.　1, the same or similar structure may be used in one or more of the various client devices　106-116. For example, a desktop computer 106 or a laptop computer 112 may have the same or similar structure as that shown in FIG. 2.

[0076] FIG. 3 illustrates an example electronic device 300, and the electronic device　300 may represent one or more of the client devices 106-116 in FIG. 1. The electronic device 300 may be a mobile communication device, such as, for example, a mobile station, a subscriber station, a wireless terminal, a desktop computer (similar to the desktop computer　106 of FIG. 1), a portable electronic device (similar to the mobile device 108, the PDA　110, the laptop computer 112, the tablet computer 114, or the HMD 116 of FIG.　1), and the like. In certain embodiments, one or more of the client devices 106-116 of FIG.　1 may include the same or similar configuration as the electronic device 300. In certain embodiments, the electronic device 300 may be an encoder, a decoder, or both. For example, the electronic device 300 may be usable with data transfer, image or video compression, image or video decompression, encoding, decoding, and media rendering applications.

[0077] As shown in FIG. 3, the electronic device 300 may include an antenna　305, a radio-frequency　(RF)　transceiver 310, transmit (TX) processing circuitry 315, a microphone 320, and receive (RX) processing circuitry 325. The RF transceiver 310 may include, for example, a RF transceiver, a BLUETOOTH transceiver, a WI-FI transceiver, a ZIGBEE transceiver, an infrared transceiver, and various other wireless communication signals. The electronic device　300 may also include a speaker　330, a processor 340, an input / output　(I / O) interface (IF) 345, an input 350, a display　355, a memory 360, and a sensor(s) 365. The memory 360 may include an operating system (OS)　361, and one or more applications 362.

[0078] The RF transceiver 310 may receive, from the antenna 305, an incoming RF signal transmitted from an access point (such as a base station, WI-FI router, or BLUETOOTH device) or other device of the network 102 (such as a WI-FI, BLUETOOTH, cellular, 5G, LTE, LTE-A, WiMAX, or any other type of wireless network). The RF transceiver 310 may down-convert the incoming RF signal to generate an intermediate frequency or baseband signal. The intermediate frequency or baseband signal may be sent to the RX processing circuitry 325 that generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or intermediate frequency signal. The RX processing circuitry 325 may transmit the processed baseband signal to the speaker　330 (such as for voice data) or to the processor 340 for further processing (such as for web browsing data).

[0079] The TX processing circuitry 315 may receive analog or digital voice data from the microphone 320 or other outgoing baseband data from the processor 340. The outgoing baseband data may include web data, e-mail, or interactive video game data. The TX processing circuitry　315 may encode, multiplexe, and / or digitize the outgoing baseband data to generate a processed baseband or intermediate frequency signal. The RF transceiver　310 may receive the outgoing processed baseband or intermediate frequency signal from the TX processing circuitry　315 and up-convert the baseband or intermediate frequency signal to an RF signal that is transmitted via the antenna 305.

[0080] The processor 340 may include one or more processors or other processing devices. The processor 340 may execute instructions that are stored in the memory 360, such as the OS　361 in order to control the overall operation of the electronic device 300. For example, the processor　340 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 310, the RX processing circuitry 325, and the　TX processing circuitry　315 in accordance with well-known principles. The processor　340 may include any suitable number(s) and type(s) of processors or other devices in any suitable arrangement. For example, in certain embodiments, the processor 340 may include at least one microprocessor or microcontroller. For example, types of processor 340 may include microprocessors, microcontrollers, digital signal processors, field programmable gate arrays, application specific integrated circuits, and discrete circuitry.

[0081] The processor 340 may be also capable of executing other processes and programs resident in the memory 360, such as operations that receive and store data. The processor 340 may move data into or out of the memory　360 as required by an executing process. In certain embodiments, the processor 340 may be configured to execute the one or more applications 362 based on the OS 361 or in response to signals received from external source(s) or an operator. For example, applications 362 may include an encoder, a decoder, a VR or AR application, a camera application (for still images and videos), a video phone call application, an email client, a social media client, a SMS messaging client, a virtual assistant, and the like. In certain embodiments, the processor　340 may be configured to receive and transmit media content.

[0082] The processor 340 may be also coupled to the I / O interface 345 that provides the electronic device 300 with the ability to connect to other devices, such as client devices 106-114. The I / O interface 345 may be the communication path between these accessories and the processor　340.

[0083] The processor 340 may be also coupled to the input 350 and the display 355. The operator of the electronic device 300 may use the input 350 to enter data or inputs into the electronic device　300. The input 350 may be a keyboard, touchscreen, mouse, track ball, voice input, or other device capable of acting as a user interface to allow a user in interact with the electronic device　300. For example, the input 350 may include voice recognition processing, thereby allowing a user to input a voice command. In another example, the input 350 may include a touch panel, a (digital) pen sensor, a key, or an ultrasonic input device. The touch panel may recognize, for example, a touch input in at least one scheme, such as a capacitive scheme, a pressure sensitive scheme, an infrared scheme, or an ultrasonic scheme. The input　350 may be associated with the sensor(s)　365 and / or a camera　by providing additional input to the processor　340. In certain embodiments, the sensor　365 may includee one or more inertial measurement units (IMUs) (such as accelerometers, gyroscope, and magnetometer), motion sensors, optical sensors, cameras, pressure sensors, heart rate sensors, altimeter, and the like. The input 350 may also include a control circuit. In the capacitive scheme, the input 350 can recognize touch or proximity.

[0084] The display 355 may be a liquid crystal display (LCD), light-emitting diode (LED) display, organic LED (OLED), active matrix OLED (AMOLED), or other display capable of rendering text and / or graphics, such as from websites, videos, games, images, and the like. The display　355 may be sized to fit within a HMD. The display 355 may be a singular display screen or multiple display screens capable of creating a stereoscopic display. In certain embodiments, the display　355 may be a heads-up display (HUD). The display 355 may display 3D objects, such as a 3D point cloud or mesh.

[0085] The memory 360 may be coupled to the processor 340. Part of the memory 360 may include a RAM, and another part of the memory 360 may include a Flash memory or other ROM. The memory　360 may include persistent storage (not shown) that represents any structure(s) capable of storing and facilitating retrieval of information (such as data, program code, and / or other suitable information). The memory 360 may contain one or more components or devices supporting longer-term storage of data, such as a read only memory, hard drive, Flash memory, or optical disc. The memory 360 may also contain media content. The media content may include various types of media such as images, videos, three-dimensional content, VR content, AR content, 3D point clouds, meshes, and the like.

[0086] The electronic device 300 may further include one or more sensors 365 that can meter a physical quantity or detect an activation state of the electronic device 300 and convert metered or detected information into an electrical signal. For example, the sensor 365 may include one or more buttons for touch input, a camera, a gesture sensor, an IMU sensors (such as a gyroscope or gyro sensor and an accelerometer), an eye tracking sensor, an air pressure sensor, a magnetic sensor or magnetometer, a grip sensor, a proximity sensor, a color sensor, a bio-physical sensor, a temperature / humidity sensor, an illumination sensor, an Ultraviolet (UV) sensor, an Electromyography (EMG) sensor, an Electroencephalogram (EEG) sensor, an Electrocardiogram (ECG) sensor, an IR sensor, an ultrasound sensor, an iris sensor, a fingerprint sensor, a color sensor (such as a Red Green Blue (RGB) sensor), and the like. The sensor 365 may further include control circuits for controlling any of the sensors included therein.

[0087] As discussed in greater detail below, one or more of these sensor(s) 365 may be used to control a user interface (UI), detect UI inputs, determine the orientation and facing the direction of the user for three-dimensional content display identification, and the like. Any of these sensor(s) 365 may be located within the electronic device 300, within a secondary device operably connected to the electronic device　300, within a headset configured to hold the electronic device　300, or in a singular device where the electronic device　300 may include a headset.

[0088] The electronic device 300 may create media content such as generate a virtual object or capture (or record) content through a camera. The electronic device 300 may encode the media content to generate a bitstream, such that the bitstream may be transmitted directly to another electronic device or indirectly such as through the network 102 of FIG. 1. The electronic device 300 may receive a bitstream directly from another electronic device or indirectly such as through the network 102 of FIG. 1.

[0089] Although FIGS. 2 and 3 illustrate examples of electronic devices, various changes may be made to FIGS. 2 and 3. For example, various components in FIGS. 2 and 3 may be combined, further subdivided, or omitted and additional components may be added according to particular needs. As a particular example, the processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In addition, as with computing and communication, electronic devices and servers may come in a wide variety of configurations, and FIGS. 2 and 3 do not limit this disclosure to any particular electronic device or server.

[0090] FIG. 4 illustrates a block diagram for an encoder encoding intra frames in accordance with an embodiment.

[0091] The decoder 400 may encode a mesh to one or more bitstreams containing coded data of base mesh, coded data of a displacement between an original mesh and the base mesh, and corresponding attribute.

[0092] As shown in FIG. 4, the encoder 400 encoding intra frames in accordance with an embodiment may comprise a quantizer 401, a static mesh encoder 403, a static mesh decoder 405, a displacements updater 407, a wavelet transformer 409, a quantizer 411, an image packer 413, a video encoder 415, an image unpacker 417, an inverse quantizer 419, an inverse wavelet transformer 421, an inverse quantizer 423, a deformed mesh reconstructor 425, an attribute transfer module 427, a padding module 429, a color space converter 431, a video encoder 433, a multiplexer 435, and a controller 437.

[0093] The quantizer 401 may quantize a base mesh m(i) to generate a quantized base mesh. In some embodiments, the base mesh may have fewer vertices compared to an original mesh.

[0094] The static mesh encoder 403 may encode and compress the quantized base mesh to generate a compressed base mesh bitstream. In some embodiments, the base mesh may be compressed in a lossy or lossless manner. In some embodiments, an already existing mesh codec such as Draco may be used to compress the base mesh.

[0095] The static mesh decoder 405 may decode the compressed base mesh bitstream to generate a reconstructed quantized base mesh m'(i).

[0096] The displacements updater 407 may update displacements d(i) based on the base mesh m(i) after subdivision and the reconstructed quantized base mesh m'(i) to generate updated displacements d'(i). The reconstructed base mesh may undergo subdivision and then a displacement field between the original mesh and the subdivided reconstructed base mesh may be calculated. In inter coding of mesh frame, the base mesh may be coded by sending vertex motions instead of compressing the base mesh directly. In either case, a displacement field may be created. The displacement field as well as the modified attribute map may be coded using a video codec and also included as a part of the V-DMC bitstream.

[0097] The wavelet transformer 409 may perform a wavelet transform with the updated displacements d'(i) to generate displacement wavelet coefficients e(i). The wavelet transform may comprise a series of prediction and update lifting steps.

[0098] The quantizer 411 may quantize the displacement wavelet coefficients e(i) to generate quantized displacement wavelet coefficients e'(i). The quantized displacement wavelet coefficients may be denoted by an array dispQuantCoeffArray.

[0099] The image packer 413 may pack the quantized displacement wavelet coefficients e'(i) into a 2D image including packed quantized displacement wavelet coefficients dispQuantCoeffFrame. The 2D video frame may be referred to as a displacement frame or a displacement video frame in this disclosure.

[0100] The video encoder 415 may encode the packed quantized displacement wavelet coefficients dispQuantCoeffFrame to generate a compressed displacements bitstream.

[0101] The image unpacker 417 may unpack the packed quantized displacement wavelet coefficients dispQuantCoeffFrame to generate an array dispQuantCoeffArray of quantized displacement wavelet coefficients.

[0102] The inverse quantizer 419 may inversely quantize the array dispQuantCoeffArray of quantized displacement wavelet coefficients to generate displacement wavelet coefficients.

[0103] The inverse wavelet transformer 421 may perform an inverse wavelet transform with the displacement wavelet coefficients to generate reconstructed displacements D"(i).

[0104] The inverse quantizer 423 may inversely quantize the reconstructed quantized base mesh m'(i) to generate a reconstructed base mesh m"(i).

[0105] The deformed mesh reconstructor 425 may generate a reconstruct deformed mesh DM(i) based on the reconstructed displacements D"(i) and a reconstructed base mesh m"(i).

[0106] The attribute transfer module 427 may update an attribute map A(i) based on a static / dymanic mesh m(i) and a reconstructed deformed mesh DM(i) to generate an updated attribute map A'(i). The attribute map may be a texture map but other attributes may be sent as well.

[0107] The padding module 429 may perform padding to fill empty areas in the updated attribute map A'(i) so as to remove high frequency components.

[0108] The color space converter 431 may perform a color space conversion of the padded updated attribute map A'(i).

[0109] The video encoder 433 may encode the output of the color space converter 431 to generate the compressed attribute bitstream.

[0110] The multiplexer 435 may multiplex the compressed base mesh bitstream, the compressed displacements bitstream, and the compressed attribute bitstream to generate a compressed bitstream b(i).

[0111] The controller 437 may control modules of the encoder 400.

[0112] FIG. 5 illustrates a block diagram for a decoder in accordance with an embodiment.

[0113] As shown in FIG. 5, the decoder 500 may comprise a demultiplexer 501, a switch 503, a static mesh decoder 505, a mesh buffer 507, a motion decoder 509, a base mesh reconstructor 511, a switch 513, an inverse quantizer 515, a video decoder 521, an image unpacker 523, an inverse quantizer 525, an inverse wavelet transformer 527, a deformed mesh reconstructor 529, a video decoder 531, and a color space converter 533.

[0114] The demultiplexer 501 may receive the compressed bitstream b(i) from the encoder 400 to extract the compressed base mesh bitstream, the compressed displacements bitstream, and the compressed attribute bitstream from the compressed bitstream b(i).

[0115] The switch 503 may determine whether the compressed base mesh bitstream has an inter-coded mesh frame or an intra-coded mesh frame. If the compressed base mesh bitstream has the inter-coded mesh frame, the switch 503 may transfer the inter-coded mesh frame to the motion decoder 509. If the compressed base mesh bitstream has the intra-coded mesh frame, the switch 503 may transfer the intra-coded mesh frame to the static mesh decoder 505.

[0116] The static mesh decoder 505 may decode the intra-coded mesh frame to generate a reconstructed quantized base mesh frame.

[0117] The mesh buffer 507 may store the reconstructed quantized base mesh frames and the inter-coded mesh frame for future use of decoding subsequent inter-coded mesh frames. The reconstructed quantized base mesh frames may be used as reference mesh frames.

[0118] The motion decoder 509 may obtain motion vectors for a current inter-coded mesh frame based on data stored in the mesh buffer 507 and syntax elements in the bitstream for the current inter-coded mesh frame. In some embodiments, the syntax elements in the bitstream for the current inter-coded mesh frame may be a motion vector difference.

[0119] The base mesh reconstructor 511 may generate a reconstructed quantized base mesh frame by using syntax elements in the bitstream for the current inter-coded mesh frame based on the motion vectors for the current inter-coded mesh frame.

[0120] The switch 513 may transmit the reconstructed quantized base mesh frame from the static mesh decoder 505 to the inverse quantizer 515, if the compressed base mesh bitstream has the intra-coded mesh frame. The switch 513 may transmit the reconstructed quantized base mesh frame from the static mesh decoder 511 to the inverse quantizer 515, if the compressed base mesh bitstream has the inter-coded mesh frame.

[0121] The inverse quantizer 515 may perform an inverse quantization with the reconstructed quantized base mesh frame m'(i) to generate a reconstructed base mesh frame m"(i).

[0122] The video decoder 521 may decode a displacements bitstream to generate packed quantized displacement wavelet coefficients dispQuantCoeffFrame.

[0123] The image unpacker 523 may unpack the packed quantized displacement wavelet coefficients dispQuantCoeffFrame to generate an array dispQuantCoeffArray of quantized displacement wavelet coefficients.

[0124] The inverse quantizer 525 may perform the inverse quantization with the array dispQuantCoeffArray of quantized displacement wavelet coefficients to generate displacement wavelet coefficients.

[0125] The inverse wavelet transformer 527 may perform the inverse wavelet transform with displacement wavelet coefficients to generate displacements.

[0126] The deformed mesh reconstructor 529 may reconstruct a deformed mesh M"(i) based on the displacements and the reconstructed base mesh frame m"(i).

[0127] The video decoder 531 may decode the attribute bitstream to generate an attribute map A'(i) before a color space conversion.

[0128] The color space converter 533 may perform a color space conversion of the attribute map A'(i) from the video decoder 531 to reconstruct the attribute map A"(i).

[0129] The decoder 500 may reconstruct the deformed mesh M"(i) and the attribute map A"(i). Thus, the decoder 500 may render volumetric contents corresponding to the deformed mesh M"(i) using the attribute map A"(i).

[0130] A user may simplify a quick preview or trick play operation by utilization of a two-dimensional (2D) snapshot image of volumetric content. The 2D snapshot image is generated at a certain point of time with a camera at a certain position and direction. A user may decode a 2D snapshot image instead of volumetric contents. Volumetric contents may be decoded by decoding compressed bitstreams and compositing or rendering volumetric contents, but the operations to ultimately render the volumetric content are costly. A user may instead present the decoded 2D snapshot image.

[0131] FIG. 6 shows a basic block diagram of a 2D snapshot image supplemental enhancement information (SEI) message in accordance with an embodiment of this disclosure.

[0132] Referring to FIG. 6, the 2D snapshot SEI message processor 600 in accordance with an embodiment includes a three-dimensional (3D)-to-2D image processor 601, a packing, sorting and padding processor 603, one or more high-efficiency video coding (HEVC) encoders 605 and a multiplexer 607.

[0133] The 3D-to-2D image processor 601 may present a photo generated by a camera based on the 3D position and direction vector of a viewport camera in the 3D frame to generate a 2D snapshot image and some metadata. The packing, sorting and padding processor 603 may pack, sort and pad the 2D snapshot image to generate a geometry frame, a color frame, an occupancy map frame and some metadata. The HEVC encoder(s) 605 may encode the geometry frame, the color frame and the occupancy map frame to generate a geometry sub-bitstream, a color sub-bitstream and an occupancy map sub-bitstream. The multiplexer 607 may combine the geometry sub-bitstream, the color sub-bitstream, the occupancy map sub-bitstream and the metadata to generate a compressed bitstream.

[0134] In some embodiments, the 2D snapshot image SEI message is a data structure which provides a coded bitstream of a 2D image of a coded volumetric frame, as shown in FIG. 6, with a camera at a certain position and direction.

[0135] In some embodiments, this SEI message may contain exactly one 2D image.

[0136] In some embodiments, when present this SEI message may be located immediately before the first visual volumetric video-based coding (V3C) Unit of the coded atlas access unit comprising the coded volumetric frame corresponding to the 2D image in the SEI message excluding any V3C Unit containing non-access control list(ACL) network abstraction layer (NAL) Unit.

[0137] In some embodiments, there may be more than one 2D snapshot image SEI messages corresponding to a single coded volumetric frame, the 2D snapshot image SEI messages comprising different versions of 2D snapshot image, for example but not limited to, cameras at different positions or directions.

[0138] In some embodiments, a SEI message may provide information about a 3D position and a directional vector of a camera used to render a 2D snapshot image.

[0139] In some embodiments, the syntax and semantics for the SEI message described in the above embodiment may be defined in Table 1 below.

[0140] 2D_snapshot_image( payloadSize) {stereoscopic_flagu(1)camera_info_flagu(1)reserved_zero_7bitsu(6)if( camera_info_flag) {camera_position_xue(v)camera_position_yue(v)camera_position_zue(v)camera_direction_xi(16)camera_direction_yi(16)camera_direction_zi(16)}2D_snapshot_codecu(3)reserved_zero_5bitsu(5)2D_snapshot_codec_profileu(8)2D_snapshot_codec_levelu(8)2D_snapshot_image_widthu(16)2D_snapshot_image_heightu(16)2D_snapshot_bitstream_sizeue(v)2D_snapshot_bitstream (2D_snapshot_bitstream_size)u(v)}

[0141] Referring to Table 1, the SEI message 2D_snapshot_image may comprise a syntax element stereoscopic_flag, a syntax element 2D_snapshot_codec, a syntax element 2D_snapshot_codec_profile, a syntax element 2D_snapshot_codec_level, a syntax element 2D_snapshot_image_width, a syntax element 2D_snapshot_image_height, and a syntax element 2D_snapshot_bitstream_size.

[0142] The syntax element stereoscopic_flag may indicate whether the snapshot image supports stereoscopic presentation. In some embodiments, when the syntax element stereoscopic_flag is equal to 1, the syntax element stereoscopic_flag may indicate whether the snapshot image supports stereoscopic presentation. In some embodiments, when the syntax element stereoscopic_flag is equal to 0, the syntax element stereoscopic_flag may indicate whether the snapshot image does not support stereoscopic presentation.

[0143] The syntax element camera_info_flag may indicate whether information about the camera used to render the snapshot is provided. In some embodiments, when the syntax element camera_info_flag is equal to 1, the syntax element camera_info_flag may indicate that information about the camera used to render the snapshot is provided. In some embodiments, when the syntax element camera_info_flag is equal to 0, the syntax element camera_info_flag may indicate that information about the camera used to render the snapshot is not provided. If the syntax element camera_info_flag indicates that information about the camera used to render the snapshot is provided, the SEI message 2D_snapshot_image may further comprise a syntax element camera_position_x, a syntax element camera_position_y, a syntax element camera_position_z, a syntax element camera_direction_x, a syntax element camera_direction_y, and a syntax element camera_direction_z as the information about the camera used to render the snapshot.

[0144] The syntax element camera_position_x may specifie the x coordinate value of the position of the camera used to render the snapshot.

[0145] The syntax element camera_position_y may specifie the y coordinate value of the position of the camera used to render the snapshot.

[0146] The syntax element camera_position_z may specifie the z coordinate value of the position of the camera used to render the snapshot.

[0147] The syntax element camera_direction_x may specifie the normalized x-component value of the direction vector for the camera used to render the snapshot. In some embodiments, the value of this element may be required to be in the range of -214 to 214, inclusive. The value of this element may be computed by dividing the x-component of the actual camera direction value by 214.

[0148] The syntax element camera_direction_y may specifie the normalized y-component value of the direction vector for the camera used to render the snapshot. In some embodiments, the value of this element may be required to be in the range of -214 to 214, inclusive. The value of this element may be computed by dividing the y-component of the actual camera direction value by 214.

[0149] The syntax element camera_direction_z may specifie the normalized z-component value of the direction vector for the camera used to render the snapshot. In some embodiments, the value of this element may be required to be in the range of -214 to 214, inclusive. The value of this element may be computed by dividing the z-component of the actual camera direction value by 214.

[0150] The syntax element 2D_snapshot_codec may specifie the codec used for 2D snapshot image. Table 2 below provides the list of defined codec and corresponding values of this syntax element.

[0151] The syntax element 2D_snapshot_codec_profile may specifie the profile of the codec used for 2D snapshot image. Table 2 provides the list of defined profiles and corresponding values of this syntax element according to the codec specified by 2D_snapshot_codec field.

[0152] The syntax element 2D_snapshot_codec_level may specifie the level of the codec used for 2D snapshot image. Table 2 provides the list of defined level and corresponding values of this syntax element according to the codec specified by 2D_snapshot_codec field.

[0153] value of 2D_snapshot_codeccodecvalue of 2D_snapshot_codec_profilevalue of 2D_snapshot_codec_level0reserved--1ISO / IEC 14496-10profile code as defined in ISO / IEC 14496-10level code as defined in ISO / IEC 14496-102ISO / IEC 23008-2general_profile_idc as defined in ISO / IEC 23008-2general_level_idc as defined in ISO / IEC 23008-23ISO / IEC 23090-3general_profile_idc as defined in ISO / IEC 23090-3general_level_idc as defined in ISO / IEC 23090-34-7reserved--

[0154] Referring to Table 2, the value of 2D_snapshot_codec may comprise an integer between 0 and 7, the codec may comprise a value indicating the codec used in taking the snapshot, the value of 2D_snapshot_codec_profil may comprise a profile code of the codec used in taking the 2D snapshot, and the value of 2D_snapshot_codec_level may comprise a level code of the codec used in taking the 2D snapshot.

[0155] The syntax element 2D_snaphot_image_width may specifie the width of the 2D snapshot in the number of pixels.

[0156] The syntax element 2D_snapshot_image_height may specifie the height of the 2D snapshot in the number of pixels.

[0157] The syntax element 2D_snapshot_bitstream ( numBytes ) may comprise a bitstream encoded with the codec specified by 2D_snapshot_codec and conformant to the profile and level of the codec specified by 2D_snapshot_codec_profile and 2D_snapshot_codec_level, respectively. The 2D snapshot bitstream element may comprise a bitstream for exactly one coded picture and the information required to completely decode such picture.

[0158] In some embodiments, a 2D snapshot image track may be used where it contains one or more samples of coded bitstream of 2D image of a coded volumetric frame rendered at a certain location and direction. A sample may comprise a 2D projected image of a coded volumetric frame. The volumetric frame and the sample may share the same composition time.

[0159] In some embodiments, a single concurrent versions system (CVS) may have more than one 2D snapshot image track. A 2D snapshot image track may comprise a different version of snapshot image to other 2D snapshot image tracks for the same CVS.

[0160] In some embodiments, the 2D snapshot image track may have a restriction. The restriction may comprise the requirement that the value of handler_type of a 2D snapshot image track be 'vide.' For example, and without limitation, the track used as a 2D snapshot image may have 'vide' as a value for handler_type.

[0161] In some embodiments, all samples in the 2D snapshot image track may be required to be sync samples.

[0162] In some embodiments, a 2D snapshot image track may be associated with tracks comprising V3C data by a track reference. The V3C data may comprise V3C video components that may be encoded as independent subpictures in one picture and then divided into tracks for each V3C video component. The tracks for each V3C video component may comprise the following subpicture tracks: the occupancy video component track, the geometry video component track and the attribute video component track. The track reference may be by the track reference tool of ISO / IEC 14496-12. One or more TrackReferenceTypeBoxes may be added to a TrackReferenceBox within the TrackBox of the V3C atlas track or V3C atlas tile track. For convenience, the V3C atlas track or V3C atlas tile track may be referred to as a volumetric atlas track. In some embodiments, the volumetric atlas track may refer to the occupancy video component track, the geometry video component track and the attribute video component track. For convenience, the occupancy video component track, the geometry video component track and the attribute video component track may be referred to as volumetric data tracks. The TrackReferenceTypeBoxes may be added to a TrackReferenceBox for a 2D snapshot image track. The TrackReferenceTypeBox may Comprise an array of track_IDs. The track_IDs may designate the tracks comprising 2D snapshot images which the V3C atlas track or V3C atlas tile track references. In some embodiments, a 4CC value of reference_type of the TrackReferenceTypeBox may be required to be '2dsi'.

[0163] In some embodiments, a camera used for rendering snapshot images may have indicators. Information about the camera used to render 2D snapshot images may be provided as viewport information timed-metadata track. A viewport sample may provide information about the camera used to render the image if the viewport sample's composition time is the same as a snapshot image. A value of viewport_type may be set to '0' when the viewport timed-metadata track is provided. The viewport information timed-metadata track may reference a corresponding 2D snapshot image track instead of V3C atlas track. In some embodiments, the 2D snapshot image track may be required to use '2dci' for reference_type.

[0164] In some embodiments, a restriction, for example handler_type, to a 2D snapshot image track may be as follows: the value of handler_type of the 2D snapshot image track may be 'vide' if the 2D snapshot image track is referenced from a V3C atlas track or V3C atlas tile track with reference_type '2dsi'. For example and without limitation, a 2D snapshot image track may have 'vide' as a value for handler_type. In some embodiments, all samples in the 2D snapshot image track may be required to be sync samples.

[0165] In some embodiments, a restriction to 2D snapshot image track may be as follows: the 2D snapshot image track referenced from a V3C atlas track or V3C atlas tile track with reference_type '2dsi' may be represented in a file as restricted video. The 2D snapshot image track may use a generic sample entry 'resv' with additional requirements. The additional requirements may be that there is a variable SchemeTypeBox in RestrictedSchemeInfoBox and scheme_type is set to 'snst' and all samples in the track may be required to be sync samples.

[0166] In some embodiments, a camera used for rendering the 2D snapshot images may have indicators if information about the camera used to render 2D snapshot images is provided as viewport information timed-metadata track. A viewport sample may provide information about the camera used to render a snapshot image if the composition time of the viewport sample is the same as the snapshot image. The value viewport_type may be set to '0' if a view port time-meta data track is provided. The reference_type may be viewport information timed-metadata track and '2dci'. A timed-meta track may not have the track reference of 'cdsc' or 'cdtg' if the timed metadata track is referenced by the reference_type '2dci'.

[0167] FIG. 7 is a flowchart showing operations of a V-DMC encoder 400 in accordance with an embodiment.

[0168] Referring to FIG. 7, in step 701, the V-DMC encoder 400 may determine the camera information about the camera used to render a 2D snapshot image. As shown in Table 1, the camera information about the camera may comprise a camera position for coordinates x, y and z, and a camera direction components x, y and z. The camera direction components may determine a direction vector which is the direction the camera was facing.

[0169] In step 703, the V-DMC encoder 400 may determine 2D snapshot image information about a 2D snapshot. As shown in Table 1, the 2D snapshot image information may comprise a 2D snapshot codec, a 2D snapshot codec profile, a 2D snapshot codec level, a 2D snapshot image width, a 2D snapshot image height, and a 2D snapshot bitstream size.

[0170] In step 705, the V-DMC encoder 400 may encode a 2D snapshot image to generate a compressed 2D snapshot bitstream. The compressed 2D snapshot bitstream may include a coded bitstream of a 2D image of a coded volumetric frame rendered with a camera indicated by the camera information at the position and direction indicated by the 2D snapshot image information.

[0171] In step 707, as shown in Table 1, the V-DMC encoder 400 may generate an SEI message 2D_snapshot_image including the stereoscopic flag, the camera information flag, the 2D snapshot image information, and the compressed 2D snapshot bitstream. If the camera information flag indicates that the SEI message 2D_snapshot_image includes the camera information, the SEI message 2D_snapshot_image may further include the camera information.

[0172] In step 709, the V-DMC encoder 400 may transmit the compressed bitstream including the SEI message.

[0173] FIG. 8 is a flowchart showing operations of a V-DMC decoder 500 in accordance with an embodiment.

[0174] Referring to FIG. 8, in step 801, the V-DMC decoder 500 may receive a compressed bitstream comprising the SEI message 2D_snapshot_image. As described above, the SEI message 2D_snapshot_image may comprise the stereoscopic flag, the camera information flag, the 2D snapshot image information, and the compressed 2D snapshot bitstream. If the camera information flag indicates that the SEI message 2D_snapshot_image includes the camera information, the SEI message 2D_snapshot_image may further comprise the camera information of the camera used to generate the 2D snapshot image.

[0175] In step 803, the V-DMC decoder 500 may decode the compressed 2D snapshot bitstream based on the 2D snapshot image information to generate a 2D snapshot image.

[0176] In step 805, the V-DMC decoder 500 may present the generated 2D snapshot image. In some embodiments, the V-DMC decoder 500 may present the generated 2D snapshot image based on the camera information.

[0177] FIG. 9 is a flowchart showing operations of a V-DMC encoder 400 in accordance with another embodiment.

[0178] Referring to FIG. 9, in step 901, the V-DMC encoder 400 may obtain one or more 2D snapshot images corresponding to a coded volumetric frame. Each of the one or more 2D snapshot images may be associated with a respective one of a plurality of locations and associated with a respective one of a plurality of directions. Each of the one or more 2D snapshot images may be a 2D projected image of the coded volumetric frame rendered at an associated location and an associated direction. A composition time of each of the one or more 2D snapshot images may be the same as the composition time of the corresponding coded volumetric frame.

[0179] In step 903, the V-DMC encoder 400 may encode the one or more 2D snapshot images corresponding to the coded volumetric frame to generate one or more samples of coded bitstream of the one or more 2D snapshot images. Each of the one or more samples may be associated with a respective one of the one or more 2D snapshot images and contains a coded bitstream of an associated 2D snapshot image.

[0180] In step 905, the V-DMC encoder 400 may determine camera information about camera(s) used to generate one or more 2D snapshot images. The camera information about a camera may comprise a camera position for coordinates x, y and z, and a camera direction components x, y and z. The camera direction components may determine a direction vector which is the direction the camera was facing.

[0181] In step 907, the V-DMC encoder 400 may generate an ISO base media file format (ISOBMFF) file including a 2D snapshot image track and a viewport information timed-metadata track. In some embodiments, each of the one or more samples may be associated with a respective one of the one or more 2D snapshot images and contain a coded bitstream of an associated 2D snapshot image generated by rendering the coded volumetric frame with a camera at an associated position and an associated direction. In some embodiments, the viewport information timed-metadata track may contain the camera information. In some embodiments, the ISOBMFF file may further include an atlas track containing an array of track identifiers which designate tracks containing 2D snapshot images which the atlas track references. In some embodiments, the atlas track may be a V3C atlas track or a V3C atlas tile track. The V3C atlas track may represent the volumetric visual track containing V3C atlas bitstream in case of multi-track container. The V3C atlas tile track may represent the volumetric visual track containing portion of V3C atlas bitstream corresponding to one or more tiles in case of multi-track container.

[0182] In step 909, the V-DMC encoder 400 transmits the ISOBMFF file.

[0183] FIG. 10 is a flowchart showing operations of a V-DMC decoder 500 in accordance with another embodiment.

[0184] Referring to FIG. 10, in step 1001 the V-DMC decoder 500 may receive an ISOBMFF file. As described above, the ISOBMFF file may comprise a 2D snapshot image track and a viewport information timed-metadata track. In some embodiments, the 2D snapshot image track may comprise one or more samples of coded bitstreams of one or more 2D snapshot images. In some embodiments, each of the one or more samples may be associated with a respective one of the one or more 2D snapshot images and contain a coded bitstream of an associated 2D snapshot image generated by rendering the coded volumetric frame with a camera at an associated position and an associated direction. In some embodiments, the viewport information timed-metadata track may contain the camera information. In some embodiments, the ISOBMFF file may further include an atlas track containing an array of track identifiers which designate tracks containing 2D snapshot images which the atlas track references. In some embodiments, the atlas track may be a V3C atlas track or a V3C atlas tile track. The V3C atlas track may represent the volumetric visual track containing V3C atlas bitstream in case of multi-track container. The V3C atlas tile track may represent the volumetric visual track containing portion of V3C atlas bitstream corresponding to one or more tiles in case of multi-track container.

[0185] In step 1003, the V-DMC decoder 500 may decode the one or more samples of coded bitstreams of one or more 2D snapshot images to generate the one or more 2D snapshot images.

[0186] In step 1005, the V-DMC decoder 500 may present one or more of the 2D snapshot images of the generated 2D snapshot image track based on camera information in the viewpoint information timed-metadata track.

[0187] FIG. 11 is a flowchart showing operations of the decoder in accordance with another embodiment.

[0188] Referring to FIG. 11, in step 1101, the V-DMC decoder 500 may receive a bitstream comprising a coded three-dimensional (3D) volumetric frame, coded data of a two-dimensional (2D) image corresponding to the coded 3D volumetric frame, and image information for the 2D image. As described above, the 2D image corresponding to the coded 3D volumetric frame may be a 2D snapshot image to represent the coded 3D volumetric frame.

[0189] The image information for the 2D image may be followed by the coded 3D volumetric frame in the bitstream. The image information may include a flag indicating whether the image information comprises camera information about a camera used to render the two-dimensional image in a camera location.

[0190] In Exemplary embodiment, when the flag indicates that the image information comprises the camera information, the image information further comprises the camera information containing for a 3D position and a directional vector of a camera used to render the 2D image in the camera location.

[0191] The image information may include information on a codec used for decoding the 2D image. The image information may include information on a size of the two-dimensional image, and information on a size of the coded data. The image information and the coded data may be provided by a supplemental enhancement information (SEI) message in the bitstream.

[0192] In step 1103, the V-DMC decoder 500 may decode the coded data to reconstruct the 2D image corresponding to the coded 3D volumetric frame. The V-DMC decoder 500 may decode the coded data to reconstruct the 2D image using at least one of the information on the codec used for decoding the 2D image, the information on the size of the two-dimensional image, and the information on the size of the coded data.

[0193] In step 1105, the V-DMC decoder 500 may decode the image information to be used to present the 2D image. The V-DMC decoder 500 may present the 2D image using the image information. The V-DMC decoder 500 may present the 2D image using the camera information containing for the 3D position and the directional vector of the camera used in the camera location. The camera information about the camera may comprise coordinates x, y and z of a camera position and a camera direction components x, y and z. The camera direction components may determine a direction vector which is the direction the camera was facing.

[0194] The coded 3D volumetric frame may be reconstructed from a file in an ISOBMFF file format, the file comprising a first track and a second track. The first track may include one or more coded 2D images corresponding to the coded 3D volumetric frame. The second track may include an atlas bitstream comprising the coded 3D volumetric frame. In some embodiments, the one or more coded 2D images are sync samples. In some embodiments, the file may further comprise a track including camera information about a camera used to generate the one or more two-dimensional images. The third track may include a viewport sample. The viewport sample whose composition time is same with a snapshot image may provide information about a camera used to render the snapshot image. Time of the 2D image may be aligned the atlas bitstream. Time of the 2D image may be aligned with random access points of the atlas bitstream.

[0195] FIG. 12 is a flowchart showing operations of the encoder in accordance with another embodiment.

[0196] Referring to FIG. 12, in step 1201, the V-DMC encoder 400 may encode a three-dimensional (3D) volumetric frame to generate a coded volumetric frame.

[0197] In step 1203, the V-DMC encoder 400 may encode a two-dimensional (2D) image corresponding to the coded 3D volumetric frame to generate coded data of the 2D image.

[0198] In step 1205, the V-DMC encoder 400 may determine image information to be used to render the 2D image. In an embodiment, the image information may include information on a codec used for decoding the 2D image and information on a size of the 2D image, and information on a size of the coded data of the 2D image. The 2D image may be a 2D snapshot image to represent the 3D volumetric frame.

[0199] In an embodiment, the image information may include a flag indicating whether the image information comprises camera information about a camera used to render the 2D image in a camera location. When the flag indicates that the image information comprises the camera information, the image information may further comprise the camera information containing for a 3D position and a directional vector of the camera used to render the 2D image in the camera location. The camera information about the camera may comprise coordinates x, y and z of a camera position, and a camera direction components x, y and z. The camera direction components may determine a direction vector which is the direction the camera was facing.

[0200] In step 1207, the V-DMC encoder 400 may generate a bitstream including the coded volumetric frame, the coded data of the two-dimensional image, and the image information for the 2D image. The bitstream may be in a format of a V3C atlas bitstream, and the image information may be included in a supplemental enhancement information (SEI) message in the V3C atlas bitstream.

[0201] The coded 3D volumetric frame may be provided as a file in an ISOBMFF file format, the file comprising a first track and a second track. The first track may include one or more coded 2D images corresponding to the coded 3D volumetric frame. The second track may include an atlas bitstream comprising the coded 3D volumetric frame. In some embodiments, the one or more coded 2D images are sync samples. In some embodiments, the file may further comprise a track including camera information about a camera used to generate the one or more two-dimensional images. The third track may include a viewport sample. The viewport sample whose composition time is same with a snapshot image may provide information about a camera used to render the snapshot image. Time of the 2D image may be aligned the atlas bitstream. Time of the 2D image may be aligned with random access points of the atlas bitstream.

[0202] The various illustrative blocks, units, modules, components, methods, operations, instructions, items, and algorithms may be implemented or performed with processing circuitry.

[0203] A reference to an element in the singular is not intended to mean one and only one unless specifically so stated, but rather one or more. For example, "a" module may refer to one or more modules. An element proceeded by "a," "an," "the," or "said" does not, without further constraints, preclude the existence of additional same elements.

[0204] Headings and subheadings, if any, are used for convenience only and do not limit the subject technology. The term "exemplary" is used to mean serving as an example or illustration. To the extent that the term "include," "have," "carry," "contain," or the like is used, such term is intended to be inclusive in a manner similar to the term "comprise" as "comprise" is interpreted when employed as a transitional word in a claim. Relational terms such as first and second and the like may be used to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0205] Phrases such as an aspect, the aspect, another aspect, some aspects, one or more aspects, an implementation, the implementation, another implementation, some implementations, one or more implementations, an embodiment, the embodiment, another embodiment, some embodiments, one or more embodiments, a configuration, the configuration, another configuration, some configurations, one or more configurations, the subject technology, the disclosure, the present disclosure, other variations thereof and alike are for convenience and do not imply that a disclosure relating to such phrase(s) is essential to the subject technology or that such disclosure applies to all configurations of the subject technology. A disclosure relating to such phrase(s) may apply to all configurations, or one or more configurations. A disclosure relating to such phrase(s) may provide one or more examples. A phrase such as an aspect or some aspects may refer to one or more aspects and vice versa, and this applies similarly to other foregoing phrases.

[0206] A phrase "at least one of" preceding a series of items, with the terms "and" or "or" to separate any of the items, modifies the list as a whole, rather than each member of the list.　 The phrase "at least one of" does not require selection of at least one item; rather, the phrase allows a meaning that includes at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items.　 By way of example, each of the phrases "at least one of A, B, and C" or "at least one of A, B, or C" refers to only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0207] It is understood that the specific order or hierarchy of steps, operations, or processes disclosed is an illustration of exemplary approaches. Unless explicitly stated otherwise, it is understood that the specific order or hierarchy of steps, operations, or processes may be performed in different order. Some of the steps, operations, or processes may be performed simultaneously or may be performed as a part of one or more other steps, operations, or processes. The accompanying method claims, if any, present elements of the various steps, operations or processes in a sample order, and are not meant to be limited to the specific order or hierarchy presented. These may be performed in serial, linearly, in parallel or in different order. It should be understood that the described instructions, operations, and systems can generally be integrated together in a single software / hardware product or packaged into multiple software / hardware products.

[0208] The disclosure is provided to enable any person skilled in the art to practice the various aspects described herein. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. The disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the principles described herein may be applied to other aspects.

[0209] All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using a phrase means for or, in the case of a method claim, the element is recited using the phrase step for.

[0210] The title, background, brief description of the drawings, abstract, and drawings are hereby incorporated into the disclosure and are provided as illustrative examples of the disclosure, not as restrictive descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, in the detailed description, the description may provide illustrative examples and the various features may be grouped together in various implementations for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separately claimed subject matter.

[0211] The embodiments are provided solely as examples for understanding the invention. They are not intended and are not to be construed as limiting the scope of this invention in any manner. Although certain embodiments and examples have been provided, it will be apparent to those skilled in the art based on the disclosures herein that changes in the embodiments and examples shown may be made without departing from the scope of this invention.

[0212] The claims are not intended to be limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims and to encompass all legal equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirements of the applicable patent law, nor should they be interpreted in such a way.

Claims

1.An apparatus for video decoding comprising:a communication interface configured to receive a bitstream comprising a coded volumetric frame, coded data of a two-dimensional image corresponding to the coded volumetric frame, and image information for the two-dimensional image; anda processor operably coupled to the communication interface; the processor configured to decode the coded data to reconstruct the two-dimensional image corresponding to the coded volumetric frame, anddecode the image information to be used to present the two-dimensional image,wherein the image information includes information on a codec used for decoding the two-dimensional image and information on a size of the two-dimensional image, and information on a size of the coded data, andthe image information and the coded data are provided by a supplemental enhancement information (SEI) message in the bitstream.2.The apparatus of claim 1, wherein the image information is followed by the coded volumetric frame in the bitstream.3.The apparatus of claim 1, wherein the processor configured to present the two-dimensional image using the image information.4.The apparatus of claim 1, wherein the image information includes a flag indicating whether the image information comprises camera information about a camera used to render the two-dimensional image in a camera location.5.The apparatus of claim 4, wherein, when the flag indicates that the image information comprises the camera information, the image information further comprises the camera information containing for a three-dimensional position and a directional vector of a camera used to render the two-dimensional image in the camera location.6.An apparatus for video decoding comprising:a communication interface configured to receive a file comprising a first track and a second track, wherein the first track includes one or more coded two-dimensional images corresponding to a coded volumetric frame and the second track includes atlas bitstream; anda processor operably coupled to the communication interface; the processor configured to:decode the one or more coded two-dimensional images to generate one or more two-dimensional images; andpresent the one or more two-dimensional images.7.The apparatus of claim 6, wherein the second track references a volumetric track including volumetric data.8.The apparatus of claim 6, wherein the second track further comprises one or more identifiers which designate tracks containing two-dimensional images which the second track references.9.The apparatus of claim 8, wherein the one or more coded two-dimensional images are sync samples.10.The apparatus of claim 6, wherein the file further comprises a third track including camera information about a camera used to render the one or more two-dimensional images.11.The apparatus of claim 10, wherein the third track includes a viewport sample and the viewport sample whose composition time is same with a snapshot image provides information about a camera used to render the snapshot image.12.A method performed by an apparatus for video decoding comprising:receiving a bitstream comprising a coded volumetric frame, coded data of a two-dimensional image corresponding to the coded volumetric frame, and image information for the two-dimensional image;decoding the coded data to reconstruct the two-dimensional image corresponding to the coded volumetric frame; anddecoding the image information to be used to render the two-dimensional image,wherein the image information includes information on a codec used for decoding the two-dimensional image and information on a size of the two-dimensional image, and information on a size of the coded data, andthe image information and the coded data are provided by a supplemental enhancement information (SEI) message in the bitstream.13.A method performed by apparatus for video encoding comprising:encoding a volumetric frame to generate a coded volumetric frame;encoding a two-dimensional image corresponding to the coded volumetric frame to generate coded data of the two-dimensional image;determining image information to be used to render the two-dimensional image; andgenerating a bitstream including the coded volumetric frame, the coded data of the two-dimensional image, and the image information for the two-dimensional image,wherein the image information includes information on a codec used for decoding the two-dimensional image and information on a size of the two-dimensional image, and information on a size of the coded data, andthe image information and the coded data are included in a supplemental enhancement information (SEI) message in the bitstream.14.The method of claim 13, wherein the image information includes a flag indicating whether the image information comprises camera information about a camera used to render the two-dimensional image in a camera location.15.The method of claim 14, wherein, when the flag indicates that the image information comprises the camera information, the image information further comprises the camera information containing for a three-dimensional position and a directional vector of a camera used to render the two-dimensional image in the camera location.

Images