Classifications

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  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
  • H04N19/117—Filters, e.g. for pre-processing or post-processing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
  • H04N19/119—Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
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  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
  • H04N19/132—Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
  • H04N19/136—Incoming video signal characteristics or properties
  • H04N19/137—Motion inside a coding unit, e.g. average field, frame or block difference
  • H04N19/139—Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
  • H04N19/157—Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
  • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
  • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
  • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
  • H04N19/186—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a colour or a chrominance component
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/44—Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/70—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards

Definitions

• the disclosure relates generally to the field of data processing, and more particularly to video encoding and/or decoding (e.g., by a coder, a decoder or a codec (decoder and encoder)).
• video encoding and/or decoding e.g., by a coder, a decoder or a codec (decoder and encoder)).
• AOMedia Video 1 (AVI) is an open video coding format designed for video transmissions over the Internet. It was developed as a successor to, for example, codec extensions in the related art.
• Embodiments relate to a method, system, and computer readable medium for encoding and/or decoding video data.
• a method for encoding and/or decoding video data may include receiving video data comprising a chroma component and a luma component; parsing, deriving or selecting a number of presets for the chroma component in one frame, and a number of presets for the luma component in the one frame; and decoding the video data, wherein the method comprises performing a separate Constrained Directional Enhancement Filter (CDEF) process of filtering luma and chroma components independent from each other based on the number of presets for the chroma component in one frame, and the number of presets for the luma component in the one frame.
• CDEF Constrained Directional Enhancement Filter
• the method may include, when luma and chroma components have different partitioning or semi-decoupled partitioning, perform the separate Constrained Directional Enhancement Filter (CDEF) process of filtering luma and chroma components independent from each other; and obtaining an output of the separate CDEF process that includes the filtered reconstructed samples of luma/chroma components, wherein an input of the separate CDEF process is reconstructed samples of luma/chroma components, an intermediate output of the separate CDEF process includes using the derived filter presets and a per-block level preset index.
• CDEF Constrained Directional Enhancement Filter
• the number of presets derived for the luma component is different from the number of presets derived for the chroma component at picture level.
• the number of presets at picture level may include one of: 1, 2, 4, or 8.
• the number of presets derived and selected for the luma component in the one frame is 2, and the number of presets derived and selected for the chroma component in the one frame is 1
• the number of presets derived and selected for luma component is N, which is a positive integer, and the number of presets for chroma component is fixed as 1, which is derived as 1 in the decoder without signaling.
• the selected preset index for the current luma block is different from a selected preset index for the current chroma block, and an input of the separate CDEF process is luma/chroma reconstructed samples of current block, and the presets derived and selected at frame level.
• the output of this process is an index indicating which preset is selected for current block.
• the method may further comprise: when the number of the luma components corresponds to 8 presets and the number of the chroma component corresponds to 4 presets at frame level, select the preset index for a luma block A as 7, and the preset index for a chroma block B as 1, wherein the luma block A and the chroma block B are co-located or partially co located.
• the method may further comprise: when deriving a CDEF filtering strength of the chroma component, an input reconstructed sample is determined by current chroma coded block size.
• the method may further comprise: when current chroma block is of a certain size, an input is chroma reconstructed sample values of a current block having the certain size.
• the method may further comprise: when separate partitioning or semi de-coupled partitioning is applied to the luma and chroma blocks, luma and chroma blocks still share the same preset index, and only one of the luma or chroma block size is employed in the preset index derivation/signaling process.
• the method may further comprise: when luma and chroma components have the same coded block size, the CDEF filtering process of luma and chroma components are performed separately.
• the picture level presets may be signaled separately for luma and chroma components in a high-level parameter set, slice header, picture header, or a Supplementary Enhancement Information (SEI) message.
• SEI Supplementary Enhancement Information
• the luma presets may be signaled first, then, chroma presets are signaled.
• the block level preset indexes are signaled separately for luma and chroma components.
• a computer system for decoding video data may comprise: one or more computer- readable non-transitory storage media configured to store computer program code; and one or more computer processors configured to access said computer program code and operate as instructed by said computer program code, said computer program code including: receiving code configured to cause the one or more computer processors to receive video data comprising a chroma component and a luma component; parsing, deriving or selecting code configured to cause the one or more computer processors to parse, derive or select a number of presets for the chroma component in one frame, and a number of presets for the luma component in the one frame; and decoding code configured to cause the one or more computer processors to decode the video data, wherein the method comprises performing a separate Constrained Directional Enhancement Filter (CDEF) process of filtering luma and
• CDEF Constrained Directional Enhancement Filter
• a non-transitory computer readable medium having stored thereon a computer program for decoding video data may be configured to cause one or more computer processors to: receive video data comprising a chroma component and a luma component; parse, derive or select code configured to cause the one or more computer processors to parse, derive or select a number of presets for the chroma component in one frame, and a number of presets for the luma component in the one frame; and decode code configured to cause the one or more computer processors to decode the video data, wherein the method comprises performing a separate Constrained Directional Enhancement Filter (CDEF) process of filtering luma and chroma components independent from each other based on the number of presets for the chroma component in one frame, and the number of presets for the luma component in the one frame.
• CDEF Constrained Directional Enhancement Filter
• FIG. 1 illustrates a networked computer environment according to at least one embodiment
• FIG. 2 illustrates adaptive loop filter (ALF) filter shapes
• FIGS. 3A-3D illustrates subsampled positions for diagonal gradients
• FIG. 4 illustrates a modified block classification at virtual boundaries
• FIG. 5 illustrates a modified ALF filtering for luma component at virtual boundaries
• FIG. 6 illustrates a location of chroma samples relative to luma samples
• FIG. 7 illustrates an example of direction search for an 8x8 block
• FIG. 8 illustrates an example of direction search for an 8x8 block
• FIG. 9 illustrates an example of coding tree structures (luma and chroma).
• FIG. 10 illustrates a Separate Constrained Directional Enhancement Filter (SCDEF);
• FIG. 11 is an operational flowchart illustrating the steps carried out by a program that codes video data, according to at least one embodiment
• FIG. 12 is a block diagram of internal and external components of computers and servers depicted in FIG. 1 according to at least one embodiment
• FIG. 13 is a block diagram of an illustrative cloud computing environment including the computer system depicted in FIG. 1, according to at least one embodiment; and [0036] FIG. 14 is a block diagram of functional layers of the illustrative cloud computing environment of FIG. 13, according to at least one embodiment.
• Embodiments relate generally to the field of data processing, and more particularly to video encoding and/or decoding.
• the following described exemplary embodiments provide a system, method and computer program to, among other things, encode and/or decode video data.
• AOMedia Video 1 (AVI) is an open video coding format designed for video transmissions over the Internet. It was developed as a successor to VP9 by the Alliance for Open Media (AOMedia), a consortium founded in 2015 that includes semiconductor firms, video on demand providers, video content producers, software development companies and web browser vendors.
• FIG. 1 a functional block diagram of a networked computer environment illustrating a video coding system 100 (hereinafter “system”) for encoding and/or decoding video data according to an embodiment.
• system video coding system 100
• FIG. 1 provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements.
• the system 100 may include a computer 102 and a server computer 114.
• the computer 102 may communicate with the server computer 114 via a communication network 110 (hereinafter “network”).
• the computer 102 may include a processor 104 and a software program 108 that is stored on a data storage device 106 and is enabled to interface with a user and communicate with the server computer 114. As will be discussed below with reference to FIG.
• the computer 102 may include internal components 800 A and external components 900 A, respectively, and the server computer 114 may include internal components 800B and external components 900B, respectively.
• the computer 102 may be, for example, a mobile device, a telephone, a personal digital assistant, a netbook, a laptop computer, a tablet computer, a desktop computer, or any type of computing devices capable of running a program, accessing a network, and accessing a database.
• the server computer 114 may also operate in a cloud computing service model, such as Software as a Service (SaaS), Platform as a Service (PaaS), or Infrastructure as a Service (laaS), as discussed below with respect to FIGS. 13 and 14.
• SaaS Software as a Service
• PaaS Platform as a Service
• laaS Infrastructure as a Service
• the server computer 114 may also be located in a cloud computing deployment model, such as a private cloud, community cloud, public cloud, or hybrid cloud.
• the server computer 114 which may be used for encoding video data is enabled to run a Video Encoding or Decoding Program 116 (hereinafter “program”) that may interact with a database 112.
• program Video Encoding or Decoding Program
• the computer 102 may operate as an input device including a user interface while the program 116 may run primarily on server computer 114.
• the program 116 may run primarily on one or more computers 102 while the server computer 114 may be used for processing and storage of data used by the program 116.
• the program 116 may be a standalone program or may be integrated into a larger video encoding program.
• the Video Encoding or Decoding Program 116 may be corresponding to an encoder, a decoder, or a coded (both encoder and decoder).
• processing for the program 116 may, in some instances be shared amongst the computers 102 and the server computers 114 in any ratio.
• the program 116 may operate on more than one computer, server computer, or some combination of computers and server computers, for example, a plurality of computers 102 communicating across the network 110 with a single server computer 114.
• the program 116 may operate on a plurality of server computers 114 communicating across the network 110 with a plurality of client computers.
• the program may operate on a network server communicating across the network with a server and a plurality of client computers.
• the network 110 may include wired connections, wireless connections, fiber optic connections, or some combination thereof.
• the network 110 can be any combination of connections and protocols that will support communications between the computer 102 and the server computer 114.
• the network 110 may include various types of networks, such as, for example, a local area network (LAN), a wide area network (WAN) such as the Internet, a telecommunication network such as the Public Switched Telephone Network (PSTN), a wireless network, a public switched network, a satellite network, a cellular network (e.g., a fifth generation (5G) network, a long-term evolution (LTE) network, a third generation (3G) network, a code division multiple access (CDMA) network, etc.), a public land mobile network (PLMN), a metropolitan area network (MAN), a private network, an ad hoc network, an intranet, a fiber optic-based network, or the like, and/or a combination of these or other types of networks.
• LAN local area network
• WAN wide
• FIG. 1 The number and arrangement of devices and networks shown in FIG. 1 are provided as an example. In practice, there may be additional devices and/or networks, fewer devices and/or networks, different devices and/or networks, or differently arranged devices and/or networks than those shown in FIG. 1. Furthermore, two or more devices shown in FIG. 1 may be implemented within a single device, or a single device shown in FIG. 1 may be implemented as multiple, distributed devices. Additionally, or alternatively, a set of devices (e.g., one or more devices) of system 100 may perform one or more functions described as being performed by another set .of devices of system 100.
• a set of devices e.g., one or more devices of system 100 may perform one or more functions described as being performed by another set .of devices of system 100.
• VVC Versatile Video Coding
• ALF Adaptive Loop Filter
• VVC Vinyl 6
• 7x7 diamond shape is applied for luma component and the 5x5 diamond shape is applied for chroma components.
• each 4 x 4 block is categorized into one out of 25 classes.
• the classification index C is derived based on its directionality D and a quantized value of activity A, as follows:
• indices i and j refer to the coordinates of the upper left sample within the 4 x 4 block and R(i, j) indicates a reconstructed sample at coordinate (i, j).
• the subsampled 1-D Laplacian calculation is applied.
• the same subsampled positions are used for gradient calculation of all directions (e.g., a subsampled Laplacian calculation for all directions).
• FIG. 3A shows subsampled positions for vertical gradient
• FIG. 3B shows subsampled positions for horizontal gradient
• FIGS. 3C and 3D show subsampled portions for diagonal gradients.
• D maximum and minimum values of the gradients of horizontal and vertical to directions are set as:
• Step 1 If both are true, D is set to 0.
• Step 2 If gTM X /gTM , > 9 di,d2 / d di n d2 ’ continue from Step 3; otherwise continue from Step 4.
• Step 3. set to 2; otherwise D is set to 1.
• Step 4. set to 4; otherwise D is set to 3.
• the activity value A is calculated as:
• A is further quantized to the range of 0 to 4, inclusively, and the quantized value is denoted as A.
• no classification method is applied, i.e. a single set of ALF coefficients is applied for each chroma component.
• VVC VVC
• ALF filter parameters are signalled in adaptation parameter set (APS).
• APS adaptation parameter set
• up to 25 sets of luma filter coefficients and clipping value indexes, and up to eight sets of chroma filter coefficients and clipping value indexes could be signalled.
• filter coefficients of different classification for luma component can be merged.
• slice header the indices of the APSs used for the current slice are signaled.
• the signaling of ALF is CTU-based in VVC (Draft 8).
• Clipping value indexes which are decoded from the APS, allow determining clipping values using a table of clipping values for Luma and Chroma. These clipping values are dependent of the internal bitdepth. More precisely, the table of clipping values is obtained by the following formula:
• AlfClip ⁇ vom ⁇ d 2 B ⁇ a*n ) for n e [0../V — 1] ⁇ (Eq. 12) with B equal to the internal bitdepth, a is a pre-defmed constant value equal to 2.35, and N equal to 4 which is the number of allowed clipping values in VVC (Draft 8).
• Table 2 shows the output of equation 12.
• APS indices can be signaled to specify the luma filter sets that are used for the current slice.
• the filtering process can be further controlled at coding tree block (CTB) level.
• CTB coding tree block
• a flag is always signalled to indicate whether ALF is applied to a luma CTB.
• a luma CTB can choose a filter set among 16 fixed filter sets and the filter sets from APSs.
• a filter set index is signaled for a luma CTB to indicate which filter set is applied.
• the 16 fixed filter sets are pre-defmed and hardcoded in both the encoder and the decoder.
• an APS index is signaled in slice header to indicate the chroma filter sets being used for the current slice.
• a filter index is signaled for each chroma CTB if there is more than one chroma filter set in the APS.
• the filter coefficients may be quantized with norm equal to 128.
• a bitstream conformance is applied so that the coefficient value of the non-central position shall be in the range of -27 to 27 - 1, inclusive.
• the central position coefficient is not signalled in the bitstream and is considered as equal to 128.
• each sample R(i, j) within the CU is filtered, resulting in sample value R'(i, j) as shown below, where f(k, 1) denotes the decoded filter coefficients, K(x,y) is the clipping function and c(k, 1) denotes the decoded clipping parameters.
• the variable k and 1 vary between — where L denotes the filter length.
• the clipping function K(x,y) min(y, max(— y,x)) which corresponds to the function Clip3 (— y,y,x).
• this loop filtering method becomes a non-linear process, known as Non-Linear ALF.
• the selected clipping values are coded in the “alf data” syntax element by using a Golomb encoding scheme corresponding to the index of the clipping value in Table 2. This encoding scheme is the same as the encoding scheme for the filter index. [0079] 1.6 Virtual boundary filtering process for line buffer reduction
• a virtual boundary may be defined as a line by shifting the horizontal CTU boundary with “N” samples as shown in FIG. 4, with N equal to 4 for the Luma component and 2 for the Chroma component.
• Modified block classification is applied for the Luma component as depicted in FIG.
• the coding unit synchronous picture quadtree- based adaptive loop filter is proposed in JCTVC-C143 [3]
• the luma picture is split into several multi-level quadtree partitions, and each partition boundary is aligned to the boundaries of the largest coding units (LCUs).
• Each partition has its own filtering process and thus be called as a filter unit (FU).
• the 2-pass encoding flow is described as follows.
• the quadtree split pattern and the best filter of each FU are decided.
• the filtering distortions are estimated by FFDE during the decision process.
• the reconstructed picture is filtered.
• the CU synchronous ALF on/off control is performed.
• the first filtered picture is partially recovered by the reconstructed picture.
• a top-down splitting strategy is adopted to divide a picture into multi-level quadtree partitions by using a rate-distortion criterion. Each partition is called a filter unit.
• the splitting process aligns quadtree partitions with LCU boundaries.
• the encoding order of FUs follows the z-scan order. For example, the picture may be split into 10 FUs, and the encoding order is FU0, FU1, FU2, FU3, FU4, FU5, FU6, FU7, FU8, and FU9.
• split flags may be encoded and transmitted in z-order.
• the filter of each FU may be selected from two filter sets based on the rate-distortion criterion.
• the first set may have 1/2-symmetric square-shaped and rhombus-shaped filters newly derived for the current FU.
• the second set may come from time-delayed filter buffers; the time- delayed filter buffers store the filters previously derived for FUs of prior pictures.
• the filter with the minimum rate-distortion cost of these two sets may be chosen for the current FU.
• the rate- distortion costs of the 4 children FUs are calculated.
• the picture quadtree split pattern can be decided.
• the maximum quadtree split level is 2 in JCTVC-C143, which means the maximum number of FUs is 16.
• the correlation values for deriving Wiener coefficients of the 16 FUs at the bottom quadtree level can be reused.
• the rest FUs can derive their Wiener filters from the correlations of the 16FUs at the bottom quadtree level. Therefore, there is only one frame buffer access for deriving the filter coefficients of all FUs.
• the CU synchronous ALF on/off control is performed.
• the leaf CU can explicitly switch ALF on/off in its local region.
• the coding efficiency may be further improved by redesigning the filter coefficients according to the ALF on/off results.
• the redesigning process needs additional frame buffer accesses.
• Cross-component adaptive loop filter makes use of luma sample values to refine each chroma component.
• CC-ALF operates by applying a linear, diamond shaped filter to the luma channel for each chroma component.
• the filter coefficients are transmitted in the APS, scaled by a factor of 2 10 , and rounded for fixed point representation.
• the application of the filters is controlled on a variable block size and signalled by a context-coded flag received for each block of samples.
• the block size along with an CC-ALF enabling flag is received at the slice-level for each chroma component. In the contribution the following block sizes (in chroma samples) were supported 16x16, 32x32, 64x64.
• Y ] 0 indicates that the cross component Cb filter is not applied to block of Cb colour component samples at luma location ( xCtb, yCtb ).
• alf_cross_component_cb_idc[ xCtb » CtbLog2SizeY ][ yCtb » CtbLog2SizeY ] not equal to 0 indicates that the alf_cross_component_cb_idc[ xCtb » CtbLog2SizeY ][ yCtb » CtbLog2SizeY ]-th cross component Cb filter is applied to the block of Cb colour component samples at luma location ( xCtb, yCtb )
• Y ] indicates that the cross component Cr filter is not applied to block of Cr colour component samples at luma location ( xCtb, yCtb ).
• alf_cross_component_cr_idc[ xCtb » CtbLog2SizeY ][ yCtb » CtbLog2SizeY ] not equal to 0 indicates that the alf_cross_component_cr_idc[ xCtb » CtbLog2SizeY ][ yCtb » CtbLog2SizeY ]-th cross component Cr filter is applied to the block of Cr colour component samples at luma location ( xCtb, yCtb )
• FIG. 6 (“Location of chroma samples relative to luma samples”) of the present application illustrates the indicated relative position of the top-left chroma sample when chroma format idc is equal to 1 (4:2:0 chroma format), and chroma sample loc type top field or chroma sample loc type bottom field is equal to the value of a variable ChromaLocType.
• the region represented by the top-left 4:2:0 chroma sample (depicted as a large red square with a large red dot at its centre) is shown relative to the region represented by the top-left luma sample (depicted as a small black square with a small black dot at its centre).
• the regions represented by neighbouring luma samples are depicted as small grey squares with small grey dots at their centres.
• CDEF in-loop constrained directional enhancement filter
• SAO Sample Adaptive Offset
• CDEF is a non-linear spatial filter.
• the design of the filter has been constrained to be easily vectorizable (i.e. implementable with SIMD operations), which was not the case for other non-linear filters like the median filter and the bilateral filter.
• the CDEF design originates from the following observations.
• the amount of ringing artifacts in a coded image tends to be roughly proportional to the quantization step size.
• the amount of detail is a property of an input image, but the smallest detail retained in the quantized image tends to also be proportional to the quantization step size.
• the amplitude of the ringing is generally less than the amplitude of the details.
• CDEF works by identifying the direction of each block and then adaptively filtering along the identified direction and to a lesser degree along directions rotated 45 degrees from the identified direction.
• the filter strengths are signaled explicitly, which allows a high degree of control over the blurring.
• An efficient encoder search is designed for the filter strengths.
• CDEF is based on two previously proposed in-loop filters and the combined filter was adopted for the emerging AVI codec.
• the direction search operates on the reconstructed pixels, just after the deblocking filter. Since those pixels are available to the decoder, the directions require no signaling.
• the search operates on 8 c 8 blocks, which are small enough to adequately handle non-straight edges, while being large enough to reliably estimate directions when applied to a quantized image. Having a constant direction over an 8x8 region also makes vectorization of the filter easier.
• For each block we determine the direction that best matches the pattern in the block by minimizing the sum of squared differences (SSD) between the quantized block and the closest perfectly directional block.
• a perfectly directional block is a block where all of the pixels along a line in one direction have the same value.
• FIG. 7 is an example of direction search for an 8 c 8 block. In this case, the 45-degree direction (as shown by the box around column 12) is selected because it minimizes the error.
• D is the damping parameter
• 5® are the strengths of the primary and secondary taps, respectively, and round( ) rounds ties away from zero
• W k are the filter weights
• a set of in-loop restoration schemes are proposed for use in video coding post deblocking, to generally denoise and enhance the quality of edges, beyond the traditional deblocking operation. These schemes are switchable within a frame per suitably sized tile.
• the specific schemes described are based on separable symmetric Wiener filters and dual self-guided filters with subspace projection. Because content statistics can vary substantially within a frame, these tools are integrated within a switchable framework where different tools can be triggered in different regions of the frame.
• F is constrained to be separable so that the filtering can be implemented as separable horizontal and vertical w-tap convolutions.
• each of the horizontal and vertical filters are constrained to be symmetric.
• the sum of both the horizontal and vertical filter coefficients is assumed to sum to 1.
• the specific form of self-guided filtering we propose depends on two parameters: a radius r and a noise parameter e, and is enumerated as follows: 1. Obtain mean m and variance s 2 of pixels in a (2r + 1) x (2r + 1) window around every pixel. This can be implemented efficiently with box filtering based on integral imaging.
• Filtering is controlled by r and e, where a higher r implies a higher spatial variance and a higher e implies a higher range variance.
• FIG. 8 shows a subspace projection using cheap restorations to produce a final restoration closer to the source.
• a semi decoupled partitioning (SDP) scheme, or a semi separate tree (SST) or flexible block partitioning for chroma component may have same or different block partitioning, which is dependent on the luma coded block sizes or the luma tree depth.
• SDP semi decoupled partitioning
• SB super block
• chroma block uses the same coding tree structure as luma.
• T1 is a positive integer, such as 128 or 256.
• T2 is a positive integer, such as 1 or 2.
• SDP semi decoupled partitioning
• luma and chroma components are limited to share presets at picture level. Additionally, luma and chroma components are also limited to have the same preset index at block level. Lastly, when deriving the filter strength of chroma component, luma block size is used to determine an input of chroma component. These constraints may limit the coding efficiency of CDEF.
• one preset contains luma and chroma primary/secondary strength.
• the number of allowed/available presets are signaled at picture level.
• an index is signaled to indicate which preset is selected for current block.
• Coded block sizes of CDEF includel28xl28, 128x64, 64x64, and 64x128.
• the aforementioned limitations together may limit the performance of CDEF, especially under the situation when luma and chroma components have different partitioning scheme, such as the partitioning scheme in semi decoupled partitioning (SDP).
• SDP semi decoupled partitioning
• SCDEF Separate Constrained Directional Enhancement Filter
• CDEF filtering process of luma and chroma components are performed separately, as shown in FIG. 12.
• An input of the CDEF filtering process is the reconstructed samples of luma/chroma components.
• the intermediate output of this process includes but not limited to the derived filter presets and per-block level preset index as mentioned in the above proposed method.
• the eventual output of this process is the filtered reconstructed samples of luma/chroma components.
• the number of presets derived for luma and chroma component may be different from each other at picture level.
• An input of the CDEF filtering process is the reconstructed samples in luma/chroma component.
• the output of this process is the derived presets at picture level.
• Example number of presets at picture level include but not limited to 1, 2, 4, 8.
• the number of presets derived and selected for current luma component in one frame is 2, and the number of presets derived and selected for current chroma component in this frame is 1.
• the number of presets derived and selected for luma component is N
• N is a positive integer, such as 1, 2, 4, or 8
• the number of presets for chroma component is fixed as 1.
• the number of presets for chroma component does not need to be signaled in the bitstream, and derived as 1 in the decoder.
• FIG. 10 shows a Separate Constrained Directional Enhancement Filter (SCDEF).
• SCDEF Separate Constrained Directional Enhancement Filter
• the selected preset index for current luma and chroma block may be different from each other.
• An input of this process is luma/chroma reconstructed samples of current block, and the presets derived and selected at frame level.
• the output of this process is an index indicating which preset is selected for current block.
• the preset index selected for luma block A is 7
• the preset index selected for chroma block B is 1.
• Luma block A and chroma block B are co-located or partially co-located.
• an input reconstructed sample is determined by current chroma coded block size.
• luma and chroma blocks still share the same preset index, and only the luma (or chroma) block size is employed in the preset index derivation/signaling process.
• the CDEF filtering process of luma and chroma components are performed separately.
• the signaling of SCDEF are performed separately for luma and chroma components.
• picture level presets are signaled separately for luma and chroma components. These presets can be signaled in high-level parameter set (DPS, VPS, SPS, PPS, APS), slice header, picture header, SEI message.
• DPS high-level parameter set
• VPS variable-level parameter set
• SPS SPS
• PPS PPS
• SEI SEI message
• luma presets are signaled first, then, chroma presets are signaled.
• block level preset indexes are signaled separately for luma and chroma components.
• preset indexes of luma component are signaled first, then, preset indexes of chroma component are signaled.
• FIG. 11 an operational flowchart illustrating the steps of a method 300 for decoding video data is depicted.
• one or more process blocks of FIG. 3 may be performed by the computer 102 (FIG. 1) and the server computer 114 (FIG. 1).
• one or more process blocks of FIG. 3 may be performed by another device or a group of devices separate from or including the computer 102 and the server computer 114.
• the method 300 includes receiving video data comprising a chroma component and a luma component.
• the method 300 includes parsing, deriving or selecting a number of presets for the chroma component in one frame, and a number of presets for the luma component in the one frame.
• the method 300 includes encoding and/or decoding the video data.
• Operation 306 may be based on the number of presets for the chroma component in one frame, and the number of presets for the luma component in the one frame.
• the method may further comprise: performing a separate Constrained Directional Enhancement Filter (CDEF) process of filtering luma and chroma components independent from each other based on the number of presets for the chroma component in one frame, and the number of presets for the luma component in the one frame.
• CDEF Constrained Directional Enhancement Filter
• FIG. 11 provides only an illustration of one implementation and does not imply any limitations with regard to how different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements.
• FIG. 12 is a block diagram 400 of internal and external components of computers depicted in FIG. 1 in accordance with an illustrative embodiment. It should be appreciated that FIG. 4 provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environments may be made based on design and implementation requirements.
• Computer 102 (FIG. 1) and server computer 114 (FIG. 1) may include respective sets of internal components 800A,B and external components 900A,B illustrated in FIG 12.
• Each of the sets of internal components 800 include one or more processors 820, one or more computer- readable RAMs 822 and one or more computer-readable ROMs 824 on one or more buses 826, one or more operating systems 828, and one or more computer-readable tangible storage devices 830.
• Processor 820 is implemented in hardware, firmware, or a combination of hardware and software.
• Processor 820 is a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or another type of processing component.
• processor 820 includes one or more processors capable of being programmed to perform a function.
• Bus 826 includes a component that permits communication among the internal components 800 A, B.
• each of the computer-readable tangible storage devices 830 is a magnetic disk storage device of an internal hard drive.
• each of the computer-readable tangible storage devices 830 is a semiconductor storage device such as ROM 824, EPROM, flash memory, an optical disk, a magneto-optic disk, a solid state disk, a compact disc (CD), a digital versatile disc (DVD), a floppy disk, a cartridge, a magnetic tape, and/or another type of non-transitory computer-readable tangible storage device that can store a computer program and digital information.
• Each set of internal components 800A,B also includes a R/W drive or interface 832 to read from and write to one or more portable computer-readable tangible storage devices 936 such as a CD-ROM, DVD, memory stick, magnetic tape, magnetic disk, optical disk or semiconductor storage device.
• a software program such as the software program 108 (FIG. 1) and the Video Encoding Program 116 (FIG. 1) can be stored on one or more of the respective portable computer-readable tangible storage devices 936, read via the respective R/W drive or interface 832 and loaded into the respective hard drive 830.
• Each set of internal components 800A,B also includes network adapters or interfaces 836 such as a TCP/IP adapter cards; wireless Wi-Fi interface cards; or 3G, 4G, or 5G wireless interface cards or other wired or wireless communication links.
• the software program 108 (FIG. 1) and the Video Encoding Program 116 (FIG. 1) on the server computer 114 (FIG. 1) can be downloaded to the computer 102 (FIG. 1) and server computer 114 from an external computer via a network (for example, the Internet, a local area network or other, wide area network) and respective network adapters or interfaces 836.
• the network may comprise copper wires, optical fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers.
• Each of the sets of external components 900A,B can include a computer display monitor 920, a keyboard 930, and a computer mouse 934. External components 900A,B can also include touch screens, virtual keyboards, touch pads, pointing devices, and other human interface devices.
• Each of the sets of internal components 800A,B also includes device drivers 840 to interface to computer display monitor 920, keyboard 930 and computer mouse 934.
• the device drivers 840, R/W drive or interface 832 and network adapter or interface 836 comprise hardware and software (stored in storage device 830 and/or ROM 824).
• Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service.
• This cloud model may include at least five characteristics, at least three service models, and at least four deployment models.
• On-demand self-service a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service’s provider.
• Broad network access capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs).
• Resource pooling the provider’s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter).
• Rapid elasticity capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.
• Measured service cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported providing transparency for both the provider and consumer of the utilized service.
• level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts).
• SaaS Software as a Service: the capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure.
• the applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based e- mail).
• a web browser e.g., web-based e- mail.
• the consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.
• PaaS Platform as a Service
• the consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations.
• laaS Infrastructure as a Service
• the consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).
• Private cloud the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises.
• Public cloud the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.
• Hybrid cloud the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load balancing between clouds).
• a cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability.
• An infrastructure comprising a network of interconnected nodes.
• cloud computing environment 500 comprises one or more cloud computing nodes 10 with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone 54A, desktop computer 54B, laptop computer 54C, and/or automobile computer system 54N may communicate.
• Cloud computing nodes 10 may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof.
• This allows cloud computing environment 600 to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device.
• computing devices 54A-N shown in FIG. 13 are intended to be illustrative only and that cloud computing nodes 10 and cloud computing environment 500 can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser).
• FIG. 14 a set of functional abstraction layers 600 provided by cloud computing environment 500 (FIG. 13) is shown. It should be understood in advance that the components, layers, and functions shown in FIG. 6 are intended to be illustrative only and embodiments are not limited thereto. As depicted, the following layers and corresponding functions are provided:
• Hardware and software layer 60 includes hardware and software components.
• hardware components include: mainframes 61; RISC (Reduced Instruction Set Computer) architecture based servers 62; servers 63; blade servers 64; storage devices 65; and networks and networking components 66.
• software components include network application server software 67 and database software 68.
• Virtualization layer 70 provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers 71; virtual storage 72; virtual networks 73, including virtual private networks; virtual applications and operating systems 74; and virtual clients 75.
• management layer 80 may provide the functions described below.
• Resource provisioning 81 provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment.
• Metering and Pricing 82 provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may comprise application software licenses.
• Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources.
• User portal 83 provides access to the cloud computing environment for consumers and system administrators.
• Service level management 84 provides cloud computing resource allocation and management such that required service levels are met.
• Service Level Agreement (SLA) planning and fulfillment 85 provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA.
• SLA Service Level Agreement
• Workloads layer 90 provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation 91; software development and lifecycle management 92; virtual classroom education delivery 93; data analytics processing 94; transaction processing 95; and Video Encoding/Decoding 96.
• Some embodiments may relate to a system, a method, and/or a computer readable medium at any possible technical detail level of integration
• the computer readable medium may include a computer-readable non-transitory storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out operations.
• the computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device.
• the computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing.
• a non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing.
• RAM random access memory
• ROM read-only memory
• EPROM or Flash memory erasable programmable read-only memory
• SRAM static random access memory
• CD-ROM compact disc read-only memory
• DVD digital versatile disk
• memory stick a floppy disk
• a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon
• a computer readable storage medium is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.
• Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network.
• the network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers.
• a network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.
• Computer readable program code/instructions for carrying out operations may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the "C" programming language or similar programming languages.
• the computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server.
• the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
• electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects or operations.
• These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
• These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.
• the computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
• each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s).
• the method, computer system, and computer readable medium may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in the Figures.
• the functions noted in the blocks may occur out of the order noted in the Figures.
• the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.”
• the term “set” is intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, etc.), and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used.
• the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
• HEVC High Efficiency Video Coding
• HDR high dynamic range
• SDR standard dynamic range
• WC Versatile Video Coding
• JVET Joint Video Exploration Team MPM: most probable mode
• WAIP Wide-Angle Intra
• CU Coding Cinit
• CTB Coding Tree Block
• PU Prediction
• Elnit TU Transform Elnit CTU: Coding Tree Unit
• VPS Video Parameter Set
• ALF Adaptive Loop Filter
• CC-ALF Cross-Component Adaptive Loop Filter
• CDEF Constrained Directional Enhancement Filter LR: Loop Restoration Filter

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