Patent Publication Number: US-11388437-B2

Title: View-position and angle dependent processing of point cloud data

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to provisional applications U.S. 62/868,797 filed on Jun. 28, 2019 which is hereby expressly incorporated by reference, in its entirety, into the present application. 
    
    
     BACKGROUND 
     1. Field 
     The present disclosure is directed a set of advanced video coding technologies including an improved scheme view-position and angle dependent processing of point cloud data. 
     2. Description of Related Art 
     Virtual reality streaming, such as of images and audio, may limit the view experienced by a user to a panorama like view of a three dimensional image by allowing the user to view different portions of the image at different angles in an x-, y-, z-axis environment without allowing for efficient streaming with respect to additional dimensions allowing a user to also experience such virtual reality also with respect to different front/back, up/down, and left/right view positions in addition to such different angles at one or more of those positions. 
     Therefore, there is a desire for a technical solution to such problems. 
     SUMMARY 
     There is included a method and apparatus comprising memory configured to store computer program code and a processor or processors configured to access the computer program code and operate as instructed by the computer program code. The computer program selecting code is configured to cause the processor implement acquisition code configured to cause the processor to acquire volumetric data of at least one visual three-dimensional (3D) scene, converting code configured to cause the processor to convert the volumetric data to point cloud data, projecting code configured to cause the processor to project the point cloud data onto two-dimensional (2D) images, encoding code configured to cause the processor to encode the point cloud data projected onto the 2D images, and composing code configured to cause the processor to compose a media file encapsulating both metadata and the encoded point cloud data, where the metadata indicates a six-degrees-of-freedom (6DoF) media. 
     According to exemplary embodiments, the encoding code is further configured to cause the processor to partition the point cloud data into a plurality of partitions. 
     According to exemplary embodiments, the encoding code is further configured to cause the processor to encode the partitions independent of each other. 
     According to exemplary embodiments, the composing code is further configured to cause the processor to compose the media file by adding each encoded partition to the media file. 
     According to exemplary embodiments, the metadata indicates layout information of the partitions. 
     According to exemplary embodiments, the plurality of partitions comprise a plurality of 3D partitions on a 6DoF coordinate system, and the metadata further indicates 3D positions of the 3D partitions on the 6DoF coordinate system. 
     According to exemplary embodiments, the computer program selecting code is further configured to cause the processor to implement transmitting code configured to cause the processor to transmit the media file to at least one of a cloud server and a media player. 
     According to exemplary embodiments, the metadata further indicates at least one view position and at least one angle at the at least one view position on a 6DoF coordinate system. 
     According to exemplary embodiments, the metadata comprises 360-degree virtual reality (360VR) data. 
     According to exemplary embodiments, wherein the encoded point cloud data comprises point cloud reconstruction metadata. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features, nature, and various advantages of the disclosed subject matter will be more apparent from the following detailed description and the accompanying drawings in which: 
         FIGS. 1-9B  are schematic illustrations of diagrams in accordance with embodiments. 
         FIGS. 10 and 11  are simplified block diagrams in accordance with embodiments. 
         FIG. 12  is a schematic illustration of a diagram in accordance with embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The proposed features discussed below may be used separately or combined in any order. Further, the embodiments may be implemented by processing circuitry (e.g., one or more processors or one or more integrated circuits). In one example, the one or more processors execute a program that is stored in a non-transitory computer-readable medium. 
       FIG. 1  illustrates a simplified block diagram of a communication system  100  according to an embodiment of the present disclosure. The communication system  100  may include at least two terminals  102  and  103  interconnected via a network  105 . For unidirectional transmission of data, a first terminal  103  may code video data at a local location for transmission to the other terminal  102  via the network  105 . The second terminal  102  may receive the coded video data of the other terminal from the network  105 , decode the coded data and display the recovered video data. Unidirectional data transmission may be common in media serving applications and the like. 
       FIG. 1  illustrates a second pair of terminals  101  and  104  provided to support bidirectional transmission of coded video that may occur, for example, during videoconferencing. For bidirectional transmission of data, each terminal  101  and  104  may code video data captured at a local location for transmission to the other terminal via the network  105 . Each terminal  101  and  104  also may receive the coded video data transmitted by the other terminal, may decode the coded data and may display the recovered video data at a local display device. 
     In  FIG. 1 , the terminals  101 ,  102 ,  103  and  104  may be illustrated as servers, personal computers and smart phones but the principles of the present disclosure are not so limited. Embodiments of the present disclosure find application with laptop computers, tablet computers, media players and/or dedicated video conferencing equipment. The network  105  represents any number of networks that convey coded video data among the terminals  101 ,  102 ,  103  and  104 , including for example wireline and/or wireless communication networks. The communication network  105  may exchange data in circuit-switched and/or packet-switched channels. Representative networks include telecommunications networks, local area networks, wide area networks and/or the Internet. For the purposes of the present discussion, the architecture and topology of the network  105  may be immaterial to the operation of the present disclosure unless explained herein below. 
       FIG. 2  illustrates, as an example for an application for the disclosed subject matter, the placement of a video encoder and decoder in a streaming environment. The disclosed subject matter can be equally applicable to other video enabled applications, including, for example, video conferencing, digital TV, storing of compressed video on digital media including CD, DVD, memory stick and the like, and so on. 
     A streaming system may include a capture subsystem  203 , that can include a video source  201 , for example a digital camera, creating, for example, an uncompressed video sample stream  213 . That sample stream  213  may be emphasized as a high data volume when compared to encoded video bitstreams and can be processed by an encoder  202  coupled to the camera  201 . The encoder  202  can include hardware, software, or a combination thereof to enable or implement aspects of the disclosed subject matter as described in more detail below. The encoded video bitstream  204 , which may be emphasized as a lower data volume when compared to the sample stream, can be stored on a streaming server  205  for future use. One or more streaming clients  212  and  207  can access the streaming server  205  to retrieve copies  208  and  206  of the encoded video bitstream  204 . A client  212  can include a video decoder  211  which decodes the incoming copy of the encoded video bitstream  208  and creates an outgoing video sample stream  210  that can be rendered on a display  209  or other rendering device (not depicted). In some streaming systems, the video bitstreams  204 ,  206  and  208  can be encoded according to certain video coding/compression standards. Examples of those standards are noted above and described further herein. 
       FIG. 3  may be a functional block diagram of a video decoder  300  according to an embodiment of the present invention. 
     A receiver  302  may receive one or more codec video sequences to be decoded by the decoder  300 ; in the same or another embodiment, one coded video sequence at a time, where the decoding of each coded video sequence is independent from other coded video sequences. The coded video sequence may be received from a channel  301 , which may be a hardware/software link to a storage device which stores the encoded video data. The receiver  302  may receive the encoded video data with other data, for example, coded audio data and/or ancillary data streams, that may be forwarded to their respective using entities (not depicted). The receiver  302  may separate the coded video sequence from the other data. To combat network jitter, a buffer memory  303  may be coupled in between receiver  302  and entropy decoder/parser  304  (“parser” henceforth). When receiver  302  is receiving data from a store/forward device of sufficient bandwidth and controllability, or from an isosychronous network, the buffer  303  may not be needed, or can be small. For use on best effort packet networks such as the Internet, the buffer  303  may be required, can be comparatively large and can advantageously of adaptive size. 
     The video decoder  300  may include a parser  304  to reconstruct symbols  313  from the entropy coded video sequence. Categories of those symbols include information used to manage operation of the decoder  300 , and potentially information to control a rendering device such as a display  312  that is not an integral part of the decoder but can be coupled to it. The control information for the rendering device(s) may be in the form of Supplementary Enhancement Information (SEI messages) or Video Usability Information (VUI) parameter set fragments (not depicted). The parser  304  may parse/entropy-decode the coded video sequence received. The coding of the coded video sequence can be in accordance with a video coding technology or standard, and can follow principles well known to a person skilled in the art, including variable length coding, Huffman coding, arithmetic coding with or without context sensitivity, and so forth. The parser  304  may extract from the coded video sequence, a set of subgroup parameters for at least one of the subgroups of pixels in the video decoder, based upon at least one parameters corresponding to the group. Subgroups can include Groups of Pictures (GOPs), pictures, tiles, slices, macroblocks, Coding Units (CUs), blocks, Transform Units (TUs), Prediction Units (PUs) and so forth. The entropy decoder/parser may also extract from the coded video sequence information such as transform coefficients, quantizer parameter values, motion vectors, and so forth. 
     The parser  304  may perform entropy decoding/parsing operation on the video sequence received from the buffer  303 , so to create symbols  313 . The parser  304  may receive encoded data, and selectively decode particular symbols  313 . Further, the parser  304  may determine whether the particular symbols  313  are to be provided to a Motion Compensation Prediction unit  306 , a scaler/inverse transform unit  305 , an Intra Prediction Unit  307 , or a loop filter  311 . 
     Reconstruction of the symbols  313  can involve multiple different units depending on the type of the coded video picture or parts thereof (such as: inter and intra picture, inter and intra block), and other factors. Which units are involved, and how, can be controlled by the subgroup control information that was parsed from the coded video sequence by the parser  304 . The flow of such subgroup control information between the parser  304  and the multiple units below is not depicted for clarity. 
     Beyond the functional blocks already mentioned, decoder  300  can be conceptually subdivided into a number of functional units as described below. In a practical implementation operating under commercial constraints, many of these units interact closely with each other and can, at least partly, be integrated into each other. However, for the purpose of describing the disclosed subject matter, the conceptual subdivision into the functional units below is appropriate. 
     A first unit is the scaler/inverse transform unit  305 . The scaler/inverse transform unit  305  receives quantized transform coefficient as well as control information, including which transform to use, block size, quantization factor, quantization scaling matrices, etc. as symbol(s)  313  from the parser  304 . It can output blocks comprising sample values, that can be input into aggregator  310 . 
     In some cases, the output samples of the scaler/inverse transform  305  can pertain to an intra coded block; that is: a block that is not using predictive information from previously reconstructed pictures, but can use predictive information from previously reconstructed parts of the current picture. Such predictive information can be provided by an intra picture prediction unit  307 . In some cases, the intra picture prediction unit  307  generates a block of the same size and shape of the block under reconstruction, using surrounding already reconstructed information fetched from the current (partly reconstructed) picture  309 . The aggregator  310 , in some cases, adds, on a per sample basis, the prediction information the intra prediction unit  307  has generated to the output sample information as provided by the scaler/inverse transform unit  305 . 
     In other cases, the output samples of the scaler/inverse transform unit  305  can pertain to an inter coded, and potentially motion compensated block. In such a case, a Motion Compensation Prediction unit  306  can access reference picture memory  308  to fetch samples used for prediction. After motion compensating the fetched samples in accordance with the symbols  313  pertaining to the block, these samples can be added by the aggregator  310  to the output of the scaler/inverse transform unit (in this case called the residual samples or residual signal) so to generate output sample information. The addresses within the reference picture memory form where the motion compensation unit fetches prediction samples can be controlled by motion vectors, available to the motion compensation unit in the form of symbols  313  that can have, for example X, Y, and reference picture components. Motion compensation also can include interpolation of sample values as fetched from the reference picture memory when sub-sample exact motion vectors are in use, motion vector prediction mechanisms, and so forth. 
     The output samples of the aggregator  310  can be subject to various loop filtering techniques in the loop filter unit  311 . Video compression technologies can include in-loop filter technologies that are controlled by parameters included in the coded video bitstream and made available to the loop filter unit  311  as symbols  313  from the parser  304 , but can also be responsive to meta-information obtained during the decoding of previous (in decoding order) parts of the coded picture or coded video sequence, as well as responsive to previously reconstructed and loop-filtered sample values. 
     The output of the loop filter unit  311  can be a sample stream that can be output to the render device  312  as well as stored in the reference picture memory  557  for use in future inter-picture prediction. 
     Certain coded pictures, once fully reconstructed, can be used as reference pictures for future prediction. Once a coded picture is fully reconstructed and the coded picture has been identified as a reference picture (by, for example, parser  304 ), the current reference picture  309  can become part of the reference picture buffer  308 , and a fresh current picture memory can be reallocated before commencing the reconstruction of the following coded picture. 
     The video decoder  300  may perform decoding operations according to a predetermined video compression technology that may be documented in a standard, such as ITU-T Rec. H.265. The coded video sequence may conform to a syntax specified by the video compression technology or standard being used, in the sense that it adheres to the syntax of the video compression technology or standard, as specified in the video compression technology document or standard and specifically in the profiles document therein. Also necessary for compliance can be that the complexity of the coded video sequence is within bounds as defined by the level of the video compression technology or standard. In some cases, levels restrict the maximum picture size, maximum frame rate, maximum reconstruction sample rate (measured in, for example megasamples per second), maximum reference picture size, and so on. Limits set by levels can, in some cases, be further restricted through Hypothetical Reference Decoder (HRD) specifications and metadata for HRD buffer management signaled in the coded video sequence. 
     In an embodiment, the receiver  302  may receive additional (redundant) data with the encoded video. The additional data may be included as part of the coded video sequence(s). The additional data may be used by the video decoder  300  to properly decode the data and/or to more accurately reconstruct the original video data. Additional data can be in the form of, for example, temporal, spatial, or signal-to-noise ratio (SNR) enhancement layers, redundant slices, redundant pictures, forward error correction codes, and so on. 
       FIG. 4  may be a functional block diagram of a video encoder  400  according to an embodiment of the present disclosure. 
     The encoder  400  may receive video samples from a video source  401  (that is not part of the encoder) that may capture video image(s) to be coded by the encoder  400 . 
     The video source  401  may provide the source video sequence to be coded by the encoder ( 303 ) in the form of a digital video sample stream that can be of any suitable bit depth (for example: 8 bit, 10 bit, 12 bit, . . . ), any colorspace (for example, BT.601 Y CrCB, RGB, . . . ) and any suitable sampling structure (for example Y CrCb 4:2:0, Y CrCb 4:4:4). In a media serving system, the video source  401  may be a storage device storing previously prepared video. In a videoconferencing system, the video source  401  may be a camera that captures local image information as a video sequence. Video data may be provided as a plurality of individual pictures that impart motion when viewed in sequence. The pictures themselves may be organized as a spatial array of pixels, wherein each pixel can comprise one or more samples depending on the sampling structure, color space, etc. in use. A person skilled in the art can readily understand the relationship between pixels and samples. The description below focuses on samples. 
     According to an embodiment, the encoder  400  may code and compress the pictures of the source video sequence into a coded video sequence  410  in real time or under any other time constraints as required by the application. Enforcing appropriate coding speed is one function of Controller  402 . Controller controls other functional units as described below and is functionally coupled to these units. The coupling is not depicted for clarity. Parameters set by controller can include rate control related parameters (picture skip, quantizer, lambda value of rate-distortion optimization techniques, . . . ), picture size, group of pictures (GOP) layout, maximum motion vector search range, and so forth. A person skilled in the art can readily identify other functions of controller  402  as they may pertain to video encoder  400  optimized for a certain system design. 
     Some video encoders operate in what a person skilled in the art readily recognizes as a “coding loop.” As an oversimplified description, a coding loop can consist of the encoding part of an encoder  402  (“source coder” henceforth) (responsible for creating symbols based on an input picture to be coded, and a reference picture(s)), and a (local) decoder  406  embedded in the encoder  400  that reconstructs the symbols to create the sample data that a (remote) decoder also would create (as any compression between symbols and coded video bitstream is lossless in the video compression technologies considered in the disclosed subject matter). That reconstructed sample stream is input to the reference picture memory  405 . As the decoding of a symbol stream leads to bit-exact results independent of decoder location (local or remote), the reference picture buffer content is also bit exact between local encoder and remote encoder. In other words, the prediction part of an encoder “sees” as reference picture samples exactly the same sample values as a decoder would “see” when using prediction during decoding. This fundamental principle of reference picture synchronicity (and resulting drift, if synchronicity cannot be maintained, for example because of channel errors) is well known to a person skilled in the art. 
     The operation of the “local” decoder  406  can be the same as of a “remote” decoder  300 , which has already been described in detail above in conjunction with  FIG. 3 . Briefly referring also to  FIG. 4 , however, as symbols are available and en/decoding of symbols to a coded video sequence by entropy coder  408  and parser  304  can be lossless, the entropy decoding parts of decoder  300 , including channel  301 , receiver  302 , buffer  303 , and parser  304  may not be fully implemented in local decoder  406 . 
     An observation that can be made at this point is that any decoder technology except the parsing/entropy decoding that is present in a decoder also necessarily needs to be present, in substantially identical functional form, in a corresponding encoder. The description of encoder technologies can be abbreviated as they are the inverse of the comprehensively described decoder technologies. Only in certain areas a more detail description is required and provided below. 
     As part of its operation, the source coder  403  may perform motion compensated predictive coding, which codes an input frame predictively with reference to one or more previously-coded frames from the video sequence that were designated as “reference frames.” In this manner, the coding engine  407  codes differences between pixel blocks of an input frame and pixel blocks of reference frame(s) that may be selected as prediction reference(s) to the input frame. 
     The local video decoder  406  may decode coded video data of frames that may be designated as reference frames, based on symbols created by the source coder  403 . Operations of the coding engine  407  may advantageously be lossy processes. When the coded video data may be decoded at a video decoder (not shown in  FIG. 4 ), the reconstructed video sequence typically may be a replica of the source video sequence with some errors. The local video decoder  406  replicates decoding processes that may be performed by the video decoder on reference frames and may cause reconstructed reference frames to be stored in the reference picture cache  405 . In this manner, the encoder  400  may store copies of reconstructed reference frames locally that have common content as the reconstructed reference frames that will be obtained by a far-end video decoder (absent transmission errors). 
     The predictor  404  may perform prediction searches for the coding engine  407 . That is, for a new frame to be coded, the predictor  404  may search the reference picture memory  405  for sample data (as candidate reference pixel blocks) or certain metadata such as reference picture motion vectors, block shapes, and so on, that may serve as an appropriate prediction reference for the new pictures. The predictor  404  may operate on a sample block-by-pixel block basis to find appropriate prediction references. In some cases, as determined by search results obtained by the predictor  404 , an input picture may have prediction references drawn from multiple reference pictures stored in the reference picture memory  405 . 
     The controller  402  may manage coding operations of the video coder  403 , including, for example, setting of parameters and subgroup parameters used for encoding the video data. 
     Output of all aforementioned functional units may be subjected to entropy coding in the entropy coder  408 . The entropy coder translates the symbols as generated by the various functional units into a coded video sequence, by loss-less compressing the symbols according to technologies known to a person skilled in the art as, for example Huffman coding, variable length coding, arithmetic coding, and so forth. 
     The transmitter  409  may buffer the coded video sequence(s) as created by the entropy coder  408  to prepare it for transmission via a communication channel  411 , which may be a hardware/software link to a storage device which would store the encoded video data. The transmitter  409  may merge coded video data from the video coder  403  with other data to be transmitted, for example, coded audio data and/or ancillary data streams (sources not shown). 
     The controller  402  may manage operation of the encoder  400 . During coding, the controller  405  may assign to each coded picture a certain coded picture type, which may affect the coding techniques that may be applied to the respective picture. For example, pictures often may be assigned as one of the following frame types: 
     An Intra Picture (I picture) may be one that may be coded and decoded without using any other frame in the sequence as a source of prediction. Some video codecs allow for different types of Intra pictures, including, for example Independent Decoder Refresh Pictures. A person skilled in the art is aware of those variants of I pictures and their respective applications and features. 
     A Predictive picture (P picture) may be one that may be coded and decoded using intra prediction or inter prediction using at most one motion vector and reference index to predict the sample values of each block. 
     A Bi-directionally Predictive Picture (B Picture) may be one that may be coded and decoded using intra prediction or inter prediction using at most two motion vectors and reference indices to predict the sample values of each block. Similarly, multiple-predictive pictures can use more than two reference pictures and associated metadata for the reconstruction of a single block. 
     Source pictures commonly may be subdivided spatially into a plurality of sample blocks (for example, blocks of 4×4, 8×8, 4×8, or 16×16 samples each) and coded on a block-by-block basis. Blocks may be coded predictively with reference to other (already coded) blocks as determined by the coding assignment applied to the blocks&#39; respective pictures. For example, blocks of I pictures may be coded non-predictively or they may be coded predictively with reference to already coded blocks of the same picture (spatial prediction or intra prediction). Pixel blocks of P pictures may be coded non-predictively, via spatial prediction or via temporal prediction with reference to one previously coded reference pictures. Blocks of B pictures may be coded non-predictively, via spatial prediction or via temporal prediction with reference to one or two previously coded reference pictures. 
     The video coder  400  may perform coding operations according to a predetermined video coding technology or standard, such as ITU-T Rec. H.265. In its operation, the video coder  400  may perform various compression operations, including predictive coding operations that exploit temporal and spatial redundancies in the input video sequence. The coded video data, therefore, may conform to a syntax specified by the video coding technology or standard being used. 
     In an embodiment, the transmitter  409  may transmit additional data with the encoded video. The source coder  403  may include such data as part of the coded video sequence. Additional data may comprise temporal/spatial/SNR enhancement layers, other forms of redundant data such as redundant pictures and slices, Supplementary Enhancement Information (SEI) messages, Visual Usability Information (VUI) parameter set fragments, and so on. 
       FIG. 5  illustrates intra prediction modes used in HEVC and JEM. To capture the arbitrary edge directions presented in natural video, the number of directional intra modes is extended from 33, as used in HEVC, to 65. The additional directional modes in JEM on top of HEVC are depicted as dotted arrows in  FIG. 1( b ) , and the planar and DC modes remain the same. These denser directional intra prediction modes apply for all block sizes and for both luma and chroma intra predictions. As shown in  FIG. 5 , the directional intra prediction modes as identified by dotted arrows, which is associated with an odd intra prediction mode index, are called odd intra prediction modes. The directional intra prediction modes as identified by solid arrows, which are associated with an even intra prediction mode index, are called even intra prediction modes. In this document, the directional intra prediction modes, as indicated by solid or dotted arrows in  FIG. 5  are also referred as angular modes. 
     In JEM, a total of 67 intra prediction modes are used for luma intra prediction. To code an intra mode, an most probable mode (MPM) list of size 6 is built based on the intra modes of the neighboring blocks. If intra mode is not from the MPM list, a flag is signaled to indicate whether intra mode belongs to the selected modes. In JEM-3.0, there are 16 selected modes, which are chosen uniformly as every fourth angular mode. In JVET-D0114 and JVET-G0060, 16 secondary MPMs are derived to replace the uniformly selected modes. 
       FIG. 6  illustrates N reference tiers exploited for intra directional modes. There is a block unit  611 , a segment A  601 , a segment B  602 , a segment C  603 , a segment D  604 , a segment E  605 , a segment F  606 , a first reference tier  610 , a second reference tier  609 , a third reference tier  608  and a fourth reference tier  607 . 
     In both HEVC and JEM, as well as some other standards such as H.264/AVC, the reference samples used for predicting the current block are restricted to a nearest reference line (row or column). In the method of multiple reference line intra prediction, the number of candidate reference lines (row or columns) are increased from one (i.e. the nearest) to N for the intra directional modes, where N is an integer greater than or equal to one.  FIG. 2  takes 4×4 prediction unit (PU) as an example to show the concept of the multiple line intra directional prediction method. An intra-directional mode could arbitrarily choose one of N reference tiers to generate the predictors. In other words, the predictor p(x,y) is generated from one of the reference samples S1, S2, . . . , and SN. A flag is signaled to indicate which reference tier is chosen for an intra-directional mode. If N is set as 1, the intra directional prediction method is the same as the traditional method in JEM 2.0. In  FIG. 6 , the reference lines  610 ,  609 ,  608  and  607  are composed of six segments  601 ,  602 ,  603 ,  604 ,  605  and  606  together with the top-left reference sample. In this document, a reference tier is also called a reference line. The coordinate of the top-left pixel within current block unit is (0,0) and the top left pixel in the 1st reference line is (−1, −1). 
     In JEM, for the luma component, the neighboring samples used for intra prediction sample generations are filtered before the generation process. The filtering is controlled by the given intra prediction mode and transform block size. If the intra prediction mode is DC or the transform block size is equal to 4×4, neighboring samples are not filtered. If the distance between the given intra prediction mode and vertical mode (or horizontal mode) is larger than predefined threshold, the filtering process is enabled. For neighboring sample filtering, [1, 2, 1] filter and bi-linear filters are used. 
     A position dependent intra prediction combination (PDPC) method is an intra prediction method which invokes a combination of the un-filtered boundary reference samples and HEVC style intra prediction with filtered boundary reference samples. Each prediction sample pred[x][y] located at (x, y) is calculated as follows:
 
pred[ x ][ y ]=( wL*R   −1,y   +wT*R   x,-1   +wTL*R   −1,-1 +(64− wL−wT−wTL )*pred[ x ][ y ]+32)&gt;&gt;6   (Eq. 2-1)
 
where R x,-1 , R −1, y  represent the unfiltered reference samples located at top and left of current sample (x, y), respectively, and R −1,-1  represents the unfiltered reference sample located at the top-left corner of the current block. The weightings are calculated as below,
 
 wT= 32&gt;&gt;(( y&lt;&lt; 1)&gt;&gt;shift)  (Eq. 2-2)
 
 wL= 32&gt;&gt;(( x&lt;&lt; 1)&gt;&gt;shift)  (Eq. 2-3)
 
 wTL =−( wL &gt;&gt;4)−( wT&gt;&gt; 4)  (Eq. 2-4)
 
shift=(log 2(width)+log 2(height)+2)&gt;&gt;2  (Eq. 2-5).
 
       FIG. 7  illustrates a diagram  700  in which DC mode PDPC weights (wL, wT, wTL) for (0, 0) and (1, 0) positions inside one 4×4 block. If PDPC is applied to DC, planar, horizontal, and vertical intra modes, additional boundary filters are not needed, such as the HEVC DC mode boundary filter or horizontal/vertical mode edge filters.  FIG. 7  illustrates the definition of reference samples Rx, −1, R−1, y and R−1, −1 for PDPC applied to the top-right diagonal mode. The prediction sample pred(x′, y′) is located at (x′, y′) within the prediction block. The coordinate x of the reference sample Rx, −1 is given by: x=x′+y′+1, and the coordinate y of the reference sample R−1, y is similarly given by: y=x′+y′+1. 
       FIG. 8  illustrates a Local Illumination Compensation (LIC) diagram  800  and is based on a linear model for illumination changes, using a scaling factor a and an offset b. And it is enabled or disabled adaptively for each inter-mode coded coding unit (CU). 
     When LIC applies for a CU, a least square error method is employed to derive the parameters a and b by using the neighboring samples of the current CU and their corresponding reference samples. More specifically, as illustrated in  FIG. 8 , the subsampled (2:1 subsampling) neighboring samples of the CU and the corresponding samples (identified by motion information of the current CU or sub-CU) in the reference picture are used. The IC parameters are derived and applied for each prediction direction separately. 
     When a CU is coded with merge mode, the LIC flag is copied from neighboring blocks, in a way similar to motion information copy in merge mode; otherwise, an LIC flag is signaled for the CU to indicate whether LIC applies or not. 
       FIG. 9A  illustrates intra prediction modes  900  used in HEVC. In HEVC, there are total 35 intra prediction modes, among which mode 10 is horizontal mode, mode 26 is vertical mode, and mode 2, mode 18 and mode 34 are diagonal modes. The intra prediction modes are signaled by three most probable modes (MPMs) and 32 remaining modes. 
       FIG. 9B  illustrates, in embodiments of VVC, there are total 87 intra prediction modes where mode 18 is horizontal mode, mode 50 is vertical mode, and mode 2, mode 34 and mode 66 are diagonal modes. Modes −1˜−10 and Modes 67˜76 are called Wide-Angle Intra Prediction (WAIP) modes. 
     The prediction sample pred(x,y) located at position (x, y) is predicted using an intra prediction mode (DC, planar, angular) and a linear combination of reference samples according to the PDPC expression:
 
pred( x,y )=( wL×R− 1, y+wT×Rx,− 1 −wTL×R− 1,−1+(64− wL−wT+wTL )×pred( x,y )+32)&gt;&gt;6
 
where Rx, −1, R−1, y represent the reference samples located at the top and left of current sample (x, y), respectively, and R−1, −1 represents the reference sample located at the top-left corner of the current block.
 
     For the DC mode the weights are calculated as follows for a block with dimensions width and height:
 
 wT= 32&gt;&gt;(( y&lt;&lt; 1)&gt;&gt; n Scale),  wL= 32&gt;&gt;(( x&lt;&lt; 1)&gt;&gt; n Scale),  wTL =( wL&gt;&gt; 4)+( wT&gt;&gt; 4),
 
with nScale=(log 2(width)−2+log 2(height)−2+2)&gt;&gt;2, where wT denotes the weighting factor for the reference sample located in the above reference line with the same horizontal coordinate, wL denotes the weighting factor for the reference sample located in the left reference line with the same vertical coordinate, and wTL denotes the weighting factor for the top-left reference sample of the current block, nScale specifies how fast weighting factors decrease along the axis (wL decreasing from left to right or wT decreasing from top to bottom), namely weighting factor decrement rate, and it is the same along x-axis (from left to right) and y-axis (from top to bottom) in current design. And 32 denotes the initial weighting factors for the neighboring samples, and the initial weighting factor is also the top (left or top-left) weightings assigned to top-left sample in current CB, and the weighting factors of neighboring samples in PDPC process should be equal to or less than this initial weighting factor.
 
     For planar mode wTL=0, while for horizontal mode wTL=wT and for vertical mode wTL=wL. The PDPC weights can be calculated with adds and shifts only. The value of pred(x,y) can be computed in a single step using Eq. 1. 
       FIG. 10  illustrates a simplified block-style workflow diagram  1000  of exemplary viewport dependent processing an in Omnidirectional Media Application Format (OMAF) that may allow for 360-degree virtual reality (VR360) streaming described in OMAF. 
     At acquisition block  1001 , video data A is acquired, such as data of multiple images and audio of same time instances in a case that the image data may represent scenes in VR360. At processing block  1003 , the images B i  of the same time instance are processed by one or more of being stitched, mapped onto a projected picture with respect to one or more virtual reality (VR) angles or other angles/viewpoint(s) and region-wise packed. Additionally, metadata may be created indicating any of such processed information and other information so as to assist in delivering and rendering processes. 
     With respect to data D, at image encoding block  1005 , the projected pictures are encoded to data E i  and composed into a media file, and in viewport-independent streaming, and at video encoding block  1004 , the video pictures are encoded as data E v  as a single-layer bitstream, for example, and with respect to data B a  the audio data may also be encoded into data E a  at audio encoding block  1002 . 
     The data E a , E v , and E i , the entire coded bitstream F i  and/or F may be stored at a (content delivery network (CDN)/cloud) server, and typically may be fully transmitted, such as at delivery block  1007  or otherwise, to an OMAF player  1020  and may be fully decoded by a decoder such that at least an area of a decoded picture corresponding to a current viewport is rendered to the user at display block  1016  with respect to the various metadata, file playback, and orientation/viewport metadata, such as an angle at which a user may be looking through a VR image device with respect to viewport specifications of that device, from the head/eye tracking block  1008 . A distinct feature of VR360 is that only a viewport may be displayed at any particular time, and such feature may be utilized to improve the performance of omnidirectional video systems, through selective delivery depending on the user&#39;s viewport (or any other criteria, such as recommended viewport timed metadata). For example, viewport-dependent delivery may be enabled by tile-based video coding according to exemplary embodiments. 
     As with the encoding blocks described above, the OMAF player  1020  according to exemplary embodiments may similarly reverse one or more facets of such encoding with respect to the file/segment decapsulation of one or more of the data F′ and/or F′ i  and metadata, decode the audio data E′ i  at audio decoding block  1010 , the video data E′ v  at video decoding block  1013 , and the image data E′ i  at image decoding block  1014  to proceed with audio rendering of the data B′ a  at audio rendering block  1011  and image rendering of the data D′ at image rendering block  1015  so as to output, in a VR360 format according to various metadata such as the orientation/viewport metadata, display data A′ i  at display block  1016  and audio data A′ s  at the loudspeakers/headphones block  1012 . The various metadata may influence ones of the data decoding and rendering processes depending on various tracks, languages, qualities, views, that may be selected by or for a user of the OMAF player  1020 , and it is to be understood that the order of processing described herein is presented for exemplary embodiments and may be implemented in other orders according to other exemplary embodiments. 
       FIG. 11  illustrates a simplified block-style content flow process diagram  1100  for (coded) point cloud data with view-position and angle dependent processing of point cloud data (herein “V-PCC”) with respect to capturing/generating/(de)coding/rendering/displaying 6 degree-of-freedom media. It is to be understood that the described features may be used separately or combined in any order and elements such as for encoding and decoding, among others illustrated, may be implemented by processing circuitry (e.g., one or more processors or one or more integrated circuits), and the one or more processors may execute a program that is stored in a non-transitory computer-readable medium according to exemplary embodiments. 
     The diagram  1100  illustrates exemplary embodiments for streaming of coded point cloud data according to V-PCC. 
     At the volumetric data acquisition block  1101 , a real-world visual scene or a computer-generated visual scene (or combination of them) may be captured by a set of camera devices or synthesized by a computer as a volumetric data, and the volumetric data, which may have an arbitrary format, may be converted to a (quantized) point cloud data format, through image processing at the converting to point cloud block  1102 . For example, data from the volumetric data may be area data by area data converted into ones of points of the point cloud by pulling one or more of the values described below from the volumetric data and any associated data into a desired point cloud format according to exemplary embodiments. According to exemplary embodiments, the volumetric data may be a 3D data set of 2D images, such as slices from which a 2D projection of the 3D data set may be projected for example. According to exemplary embodiments, point cloud data formats include representations of data points in one or more various spaces and may be used to represent the volumetric data and may offer improvements with respect to sampling and data compression, such as with respect to temporal redundancies, and, for example, a point cloud data in an x, y, z, format representing, at each point of multiple points of the cloud data, color values (e.g., RGB, etc.), luminance, intensity, etc. and could be used with progressive decoding, polygon meshing, direct rendering, octree 3D representations of 2D quadtree data. 
     At projection to images block  1103 , the acquired point cloud data may be projected onto 2D images and encoded as image/video pictures with video-based point cloud coding (V-PCC). The projected point cloud data may be composed of attributes, geometry, occupancy map, and other metadata used for point cloud data reconstruction such as with painter&#39;s algorithms, ray casting algorithms, (3D) binary space partition algorithms, among others for example. 
     At the scene generator block  1109 , on the other hand, a scene generator may generate some metadata to be used for rendering and displaying 6 degrees-of-freedom (DoF) media, by a director&#39;s intention or a user&#39;s preference for example. Such 6 DoF media may include the 360VR like 3D viewing of a scene from rotational changes on 3D axis X, Y, Z in addition to additional dimension allowing for movement front/back, up/down, and left/right with respect to a virtual experience within or at least according to point cloud coded data. The scene description metadata defines one or more scene composed of the coded point cloud data and other media data, including VR360, light field, audio, etc. and may be provided to one or more cloud servers and or file/segment encapsulation/decapsulation processing as indicated in  FIG. 11  and related descriptions. 
     After video encoding block  1104  and image encoding block  1105  similar to the video and image encoding described above (and as will be understood, audio encoding also may be provided as described above), file/segment encapsulation block  1106  processes such that the coded point cloud data are composed into a media file for file playback or a sequence of an initialization segment and media segments for streaming according to a particular media container file format such as one or more video container formats and such as may be used with respect to DASH described below, among others as such descriptions represent exemplary embodiments. The file container also may include the scene description metadata, such as from the scene generator block  1109 , into the file or the segments. 
     According to exemplary embodiments, the file is encapsulated depending on the scene description metadata to include at least one view position and at least one or more angle views at that/those view position(s) each at one or more times among the 6DoF media such that such file may be transmitted on request depending on user or creator input. Further, according to exemplary embodiments, a segment of such file may include one or more portions of such file such as a portion of that 6DoF media indicating a single viewpoint and angle thereat at one or more times; however, these are merely exemplary embodiments and may be changed depending on various conditions such as network, user, creator capabilities and inputs. 
     According to exemplary embodiments, the point cloud data is partitioned into multiple 2D/3D regions, which are independently coded such as at one or more of video encoding block  1104  and image encoding block  1105 . Then, each independently coded partition of point cloud data may encapsulated at file/segment encapsulation block  1106  as a track in a file and/or segment. According to exemplary embodiments, each point cloud track and/or a metadata track may include some useful metadata for view-position/angle dependent processing. 
     According to exemplary embodiments, the metadata, such as included in a file and/or segment encapsulated with respect to the file/segment encapsulation block, useful for the view-position/angle dependent processing includes one or more of the following: layout information of 2D/3D partitions with indices, (dynamic) mapping information associating a 3D volume partition with one or more 2D partitions (e.g. any of a tile/tile group/slice/sub-picture), 3D positions of each 3D partition on a 6DoF coordinate system, representative view position/angle lists, selected view position/angle lists corresponding to a 3D volume partition, indices of 2D/3D partitions corresponding to a selected view position/angle, quality (rank) information of each 2D/3D partition, and rendering information of each 2D/3D partition for example depending on each view position/angle. Calling on such metadata when requested, such as by a user of the V-PCC player or as directed by a content creator for the user of the V-PCC player, may allow for more efficient processing with respect to specific portions of the 6DoF media desired with respect to such metadata such that the V-PCC player may deliver higher quality images of focused on portions of the 6DoF media than other portions rather than delivering unused portions of that media. 
     From the file/segment encapsulation block  1106 , the file or one or more segments of the file may be delivered using a delivery mechanism (e.g., by Dynamic Adaptive Streaming over HTTP (DASH)) directly to any of the V-PCC player  1125  and a cloud server, such as at the cloud server block  1107  at which the cloud server can extract one or more tracks and/or one or more specific 2D/3D partitions from a file and may merge multiple coded point cloud data into one data. 
     According to data such as with the position/viewing angle tracking block  1108 , if the current viewing position and angle(s) is/are defined on a 6DoF coordinate system, at a client system, then the view-position/angle metadata may be delivered, from the file/segment encapsulation block  1106  or otherwise processed from the file or segments already at the cloud server, at cloud server block  1107  such that the cloud sever may extract appropriate partition(s) from the store file(s) and merge them (if necessary) depending on the metadata from the client system having the V-PCC player  1125  for example, and the extracted data can be delivered to the client, as a file or segments. 
     With respect to such data, at the file/segment decapsulation block  1109 , a file decapsulator processes the file or the received segments and extracts the coded bitstreams and parses the metadata, and at video decoding and image decoding blocks, the coded point cloud data are then decoded into decoded and reconstructed, at point cloud reconstruction block  1112 , to point cloud data, and the reconstructed point cloud data can be displayed at display block  1114  and/or may first be composed depending on one or more various scene descriptions at scene composition block  1113  with respect to scene description data according to the scene generator block  1109 . 
     In view of the above, such exemplary V-PCC flow represents advantages with respect to a V-PCC standard including one or more of the described partitioning capabilities for multiple 2D/3D areas, a capability of a compressed domain assembly of coded 2D/3D partitions into a single conformant coded video bitstream, and a bitstream extraction capability of coded 2D/3D of a coded picture into conformant coded bitstreams, where such V-PCC system support is further improved by including container formation for a VVC bitstream to support a mechanism to contain metadata carrying one or more of the above-described metadata. 
     Accordingly, by exemplary embodiments described herein, the technical problems noted above may be advantageously improved upon by one or more of these technical solutions. 
     The techniques described above, can be implemented as computer software using computer-readable instructions and physically stored in one or more computer-readable media or by a specifically configured one or more hardware processors. For example,  FIG. 12  shows a computer system  1200  suitable for implementing certain embodiments of the disclosed subject matter. 
     The computer software can be coded using any suitable machine code or computer language, that may be subject to assembly, compilation, linking, or like mechanisms to create code comprising instructions that can be executed directly, or through interpretation, micro-code execution, and the like, by computer central processing units (CPUs), Graphics Processing Units (GPUs), and the like. 
     The instructions can be executed on various types of computers or components thereof, including, for example, personal computers, tablet computers, servers, smartphones, gaming devices, internet of things devices, and the like. 
     The components shown in  FIG. 12  for computer system  1200  are exemplary in nature and are not intended to suggest any limitation as to the scope of use or functionality of the computer software implementing embodiments of the present disclosure. Neither should the configuration of components be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary embodiment of a computer system  1200 . 
     Computer system  1200  may include certain human interface input devices. Such a human interface input device may be responsive to input by one or more human users through, for example, tactile input (such as: keystrokes, swipes, data glove movements), audio input (such as: voice, clapping), visual input (such as: gestures), olfactory input (not depicted). The human interface devices can also be used to capture certain media not necessarily directly related to conscious input by a human, such as audio (such as: speech, music, ambient sound), images (such as: scanned images, photographic images obtain from a still image camera), video (such as two-dimensional video, three-dimensional video including stereoscopic video). 
     Input human interface devices may include one or more of (only one of each depicted): keyboard  1201 , mouse  1202 , trackpad  1203 , touch screen  1210 , joystick  1205 , microphone  1206 , scanner  1208 , camera  1207 . 
     Computer system  1200  may also include certain human interface output devices. Such human interface output devices may be stimulating the senses of one or more human users through, for example, tactile output, sound, light, and smell/taste. Such human interface output devices may include tactile output devices (for example tactile feedback by the touch-screen  1210 , or joystick  1205 , but there can also be tactile feedback devices that do not serve as input devices), audio output devices (such as: speakers  1209 , headphones (not depicted)), visual output devices (such as screens  1210  to include CRT screens, LCD screens, plasma screens, OLED screens, each with or without touch-screen input capability, each with or without tactile feedback capability—some of which may be capable to output two dimensional visual output or more than three dimensional output through means such as stereographic output; virtual-reality glasses (not depicted), holographic displays and smoke tanks (not depicted)), and printers (not depicted). 
     Computer system  1200  can also include human accessible storage devices and their associated media such as optical media including CD/DVD ROM/RW  1220  with CD/DVD  1211  or the like media, thumb-drive  1222 , removable hard drive or solid state drive  1223 , legacy magnetic media such as tape and floppy disc (not depicted), specialized ROM/ASIC/PLD based devices such as security dongles (not depicted), and the like. 
     Those skilled in the art should also understand that term “computer readable media” as used in connection with the presently disclosed subject matter does not encompass transmission media, carrier waves, or other transitory signals. 
     Computer system  1200  can also include interface  1299  to one or more communication networks  1298 . Networks  1298  can for example be wireless, wireline, optical. Networks  1298  can further be local, wide-area, metropolitan, vehicular and industrial, real-time, delay-tolerant, and so on. Examples of networks  1298  include local area networks such as Ethernet, wireless LANs, cellular networks to include GSM, 3G, 4G, 5G, LTE and the like, TV wireline or wireless wide area digital networks to include cable TV, satellite TV, and terrestrial broadcast TV, vehicular and industrial to include CANBus, and so forth. Certain networks  1298  commonly require external network interface adapters that attached to certain general-purpose data ports or peripheral buses ( 1250  and  1251 ) (such as, for example USB ports of the computer system  1200 ; others are commonly integrated into the core of the computer system  1200  by attachment to a system bus as described below (for example Ethernet interface into a PC computer system or cellular network interface into a smartphone computer system). Using any of these networks  1298 , computer system  1200  can communicate with other entities. Such communication can be uni-directional, receive only (for example, broadcast TV), uni-directional send-only (for example CANbusto certain CANbus devices), or bi-directional, for example to other computer systems using local or wide area digital networks. Certain protocols and protocol stacks can be used on each of those networks and network interfaces as described above. 
     Aforementioned human interface devices, human-accessible storage devices, and network interfaces can be attached to a core  1240  of the computer system  1200 . 
     The core  440  can include one or more Central Processing Units (CPU)  1241 , Graphics Processing Units (GPU)  1242 , a graphics adapter  1217 , specialized programmable processing units in the form of Field Programmable Gate Areas (FPGA)  1243 , hardware accelerators for certain tasks  1244 , and so forth. These devices, along with Read-only memory (ROM)  1245 , Random-access memory  1246 , internal mass storage such as internal non-user accessible hard drives, SSDs, and the like  1247 , may be connected through a system bus  1248 . In some computer systems, the system bus  1248  can be accessible in the form of one or more physical plugs to enable extensions by additional CPUs, GPU, and the like. The peripheral devices can be attached either directly to the core&#39;s system bus  1248 , or through a peripheral bus  1249 . Architectures for a peripheral bus include PCI, USB, and the like. 
     CPUs  1241 , GPUs  1242 , FPGAs  1243 , and accelerators  1244  can execute certain instructions that, in combination, can make up the aforementioned computer code. That computer code can be stored in ROM  1245  or RAM  1246 . Transitional data can be also be stored in RAM  1246 , whereas permanent data can be stored for example, in the internal mass storage  1247 . Fast storage and retrieval to any of the memory devices can be enabled through the use of cache memory, that can be closely associated with one or more CPU  1241 , GPU  1242 , mass storage  1247 , ROM  1245 , RAM  1246 , and the like. 
     The computer readable media can have computer code thereon for performing various computer-implemented operations. The media and computer code can be those specially designed and constructed for the purposes of the present disclosure, or they can be of the kind well known and available to those having skill in the computer software arts. 
     As an example and not by way of limitation, the computer system having architecture  1200 , and specifically the core  1240  can provide functionality as a result of processor(s) (including CPUs, GPUs, FPGA, accelerators, and the like) executing software embodied in one or more tangible, computer-readable media. Such computer-readable media can be media associated with user-accessible mass storage as introduced above, as well as certain storage of the core  1240  that are of non-transitory nature, such as core-internal mass storage  1247  or ROM  1245 . The software implementing various embodiments of the present disclosure can be stored in such devices and executed by core  1240 . A computer-readable medium can include one or more memory devices or chips, according to particular needs. The software can cause the core  1240  and specifically the processors therein (including CPU, GPU, FPGA, and the like) to execute particular processes or particular parts of particular processes described herein, including defining data structures stored in RAM  1246  and modifying such data structures according to the processes defined by the software. In addition or as an alternative, the computer system can provide functionality as a result of logic hardwired or otherwise embodied in a circuit (for example: accelerator  1244 ), which can operate in place of or together with software to execute particular processes or particular parts of particular processes described herein. Reference to software can encompass logic, and vice versa, where appropriate. Reference to a computer-readable media can encompass a circuit (such as an integrated circuit (IC)) storing software for execution, a circuit embodying logic for execution, or both, where appropriate. The present disclosure encompasses any suitable combination of hardware and software. 
     While this disclosure has described several exemplary embodiments, there are alterations, permutations, and various substitute equivalents, which fall within the scope of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise numerous systems and methods which, although not explicitly shown or described herein, embody the principles of the disclosure and are thus within the spirit and scope thereof