EP4022931A1 - Appareil et procédé permettant d'effectuer un déblocage - Google Patents

Appareil et procédé permettant d'effectuer un déblocage

Info

Publication number
EP4022931A1
EP4022931A1 EP20870065.8A EP20870065A EP4022931A1 EP 4022931 A1 EP4022931 A1 EP 4022931A1 EP 20870065 A EP20870065 A EP 20870065A EP 4022931 A1 EP4022931 A1 EP 4022931A1
Authority
EP
European Patent Office
Prior art keywords
block
sub
video
edge
deblocking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20870065.8A
Other languages
German (de)
English (en)
Other versions
EP4022931A4 (fr
Inventor
Jeeva Raj A
Sagar KOTECHA
Shailesh Ramamurthy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huawei Technologies Co Ltd
Original Assignee
Huawei Technologies Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co Ltd filed Critical Huawei Technologies Co Ltd
Publication of EP4022931A1 publication Critical patent/EP4022931A1/fr
Publication of EP4022931A4 publication Critical patent/EP4022931A4/fr
Pending legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • H04N19/85—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression
    • H04N19/86—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using pre-processing or post-processing specially adapted for video compression involving reduction of coding artifacts, e.g. of blockiness

Definitions

  • Embodiments of the present application generally relate to the field of picture processing and particularly to deblocking filtering for video encoding or decoding, more particularly to motion vector refinement and deblocking of the internal edges of motion vector refined blocks.
  • Image coding (encoding and decoding) is used in a wide range of digital image applications, for example broadcast digital TV, video transmission over internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems, and camcorders of security applications.
  • digital image applications for example broadcast digital TV, video transmission over internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs, video content acquisition and editing systems, and camcorders of security applications.
  • Further video coding standards comprise MPEG-1 video, MPEG-2 video, ITU-T H. 262/MPEG-2, ITU-T H. 263, ITU-T H. 264/MPEG-4, Part 10, Advanced Video Coding (AVC) , ITU-T H. 265, High Efficiency Video Coding (HEVC) , ITU-T H. 266/Versatile video coding (VVC) and extensions, e.g. scalability and/or three-dimensional (3D) extensions, of these standards.
  • AVC Advanced Video Coding
  • HEVC High Efficiency Video Coding
  • VVC Very-dimensional
  • Block-based image coding schemes have in common that along the block edges, edge artifacts can appear. These artifacts are due to the independent coding of the coding blocks. These edge artifacts are often readily visible to a user.
  • a goal in block-based image coding is to reduce edge artifacts below a visibility threshold. This is done by performing deblocking filtering. Such a deblocking filtering is on the one hand performed on decoding side in order to remove the visible edge artifacts, but also on encoding side, in order to prevent the edge artifacts from being encoded into the image at all.
  • the de-blocking filtering can be challenging.
  • an image block such as a transform unit (TU) , a prediction unit (PU) , or a coding unit (CU)
  • sub-block tools such as motion vector refined sub-blocks
  • the present disclosure aims to improve the conventional deblocking filtering.
  • the present disclosure has the objective to provide a deblocking filter apparatus, an encoder, a decoder and corresponding methods that can perform deblocking filtering with reduced processing time, such that the deblocking may be more efficient.
  • Embodiments of the present disclosure provide apparatuses and methods for encoding and decoding according to the independent claims.
  • the disclosure relates to a deblocking method. Particular aspects are outlined in the attached independent claims, with other aspects in the dependent claims.
  • block coding block or “image block” is used in the present disclosure which can be applied for transform units (TUs) , prediction units (PUs) , coding units (CUs) etc.
  • transform units and coding units are mostly aligned except in a few scenarios when TU tiling or sub-block transform (SBT) is used.
  • SBT sub-block transform
  • block/image block/coding block/transform block may be exchanged with each other in the present disclosure.
  • sample/pixel may be exchanged with each other in the present disclosure.
  • the disclosure works for both vertical and horizontal edges.
  • the disclosure allows for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block (such as a current coding unit) in an efficient way.
  • the disclosure relates to a deblocking filter apparatus.
  • Particular aspects are outlined in the attached independent claims, with other aspects in the dependent claims.
  • a first embodiment of the present disclosure provides a method for deblocking a sub-block edge between a first sub-block and a second sub-block of a current block, implemented in a video encoding device or a video decoding device, comprising, in the case that motion vector refinement is enabled and/or applied for the current block, determining, according to at least one rule, at least one filtering related parameter associated with the sub-block edge and performing deblocking filtering on the sub-block edge based on the at least one filtering related parameter, wherein the at least one rule is independent of refined motion information.
  • the sub-block edge is also referred to as a sub-block internal edge or a sub-block internal boundary in the present disclosure as it represents an edge between the first and the second sub-block of the current block.
  • the first and the second sub-block are sub-blocks adjacent to the sub-block edge wherein the sub-block edge may be a vertical or a horizontal edge.
  • the below-mentioned boundary strength as a filtering related parameter may be directly associated with the sub-block edge, i.e. the sub-block edge may be characterized by a boundary strength.
  • the below-mentioned maximum filter length as a filtering related parameter may be directly or indirectly associated with the sub-block edge.
  • a direct association can be given by a single maximum filter length for the sub-block edge, i.e. identical maximum filter lengths on either side of the sub-block edge.
  • An indirect association can be given as described below by assigning individual maximum filter lengths to the two sides of the sub-block edge.
  • the respective maximum filter length may be associated with the sub-block on the respective side of the sub-block edge, and thereby indirectly associated with the sub-block edge.
  • the individual maximum filter lengths may, in particular, differ from each other but be the same for all of the edges of a particular sub-block.
  • the motion vector refinement may in particular, be a decoder side motion vector refinement (DMVR) but is not limited to that.
  • DMVR decoder side motion vector refinement
  • the method may be implemented in a video decoding device.
  • Whether motion vector refinement is enabled may be determined in a first step, in particular from a respective indication in the bitstream such as a flag, e.g. the below-mentioned sps_dmvr_enabled_flag.
  • a second determination step may determine whether the motion vector refinement is applied to the current block, e.g. based on similarities between samples or based on an indication in the bitstream such as the below-mentioned dmvr_flag.
  • the deblocking filtering is performed, as generally known, on values of samples near the sub-block edge such as perpendicular to and adjacent to the sub-block edge.
  • the number of adjacent samples affected by the deblocking filtering may be determined based on the maximum filter length (s) of the sub-block edge or the adjacent sub-blocks, respectively.
  • the at least one rule may be independent of any refined motion vectors of the first sub-block and the second sub-block.
  • the at least one filtering related parameter may be determined independently of any refined motion information of the first sub-block and the second sub-block.
  • the at least one filtering related parameter for the deblocking filtering may be determined completely independently of any refined motion information of the first and second sub-blocks.
  • the at least one rule according to which the at least one filtering related parameter is determined rather exclusively depends on un-refined motion information, i.e. motion information available before any motion vector refinement process, such as initial motion vectors, for instance.
  • the un-refined motion information may thus be the input of the motion vector refinement.
  • the at least one filtering related parameter is determined independently of any refined motion information, it may be determined in parallel to a motion vector refinement process.
  • the deblocking filtering may therefore be performend with reduced processing time, such that the deblocking may be more efficient.
  • the at least one filtering related parameter may comprise a boundary strength (BS) for deblocking the sub-block edge. Additionally or alternatively, the at least one filtering related parameter may comprise a maximum filter length for deblocking the sub-block edge.
  • the maximum filter length may comprise a first maximum filter length for the first sub-block and a second maximum filter length for the second sub-block.
  • the step of performing deblocking filtering on the sub-block edge based on the at least one filtering related parameter may comprise modifying at most a number MA’ of sample values of the first sub-block as first output values, wherein the at most a number MA’ of the samples are in a line perpendicular to and adjacent to the sub-block edge, and modifying at most a number MB’ of sample values of the second sub-block as second output values, wherein the at most a number MB’ of the samples are in a line perpendicular to and adjacent to the sub-block edge, wherein MA’ is associated with the first maximum filter length, and MB’ is associated with the second maximum filter length.
  • MA’ may represent the first maximum filter length and MB’ may represent the second maximum filter length.
  • the at least one rule may be defined according to a quantization parameter (QP) of the current block.
  • QP quantization parameter
  • the determining the at least one filtering related parameter may comprise setting the BS for deblocking the sub-block edge to a predetermined value according to the at least one rule.
  • the determining the at least one filtering related parameter may comprise setting the maximum filter length for deblocking the sub-block edge to a predetermined value according to the at least one rule.
  • the method may further comprise comparing the QP of the current block with a first threshold, wherein the at least one rule includes, when the QP of the current block is larger than the first threshold, then a value of the BS is set to a first BS value, and/or a value of the maximum filter length is set to a first length value.
  • the method may further comprise comparing the QP of the current block with a first range of values, wherein the at least one rule includes, when the QP of the current block lies in the first range of values, then a value of the BS is set to a second BS value, and/or a value of the maximum filter length is set to a second length value.
  • the at least one rule may further include, when the QP of the current block is not larger than the first threshold and/or the QP of the current block does not lie in the first range of values, then a value of the BS is determined according to one or more initial motion vectors of the first sub-block and/or the second sub-block.
  • the at least one rule may include, when the QP of the current block is larger than 45, setting the BS to 1 and/or setting the maximum filter length to 3.
  • the at least one rule may include, when the QP of the current block is larger than 45, setting the BS to 1 and/or setting the maximum filter length to 1.
  • the at least one rule may include, when the QP of the current block is larger than 40, setting the BS to 1 and/or setting the maximum filter length to 1.
  • the at least one rule may include, when the QP of the current block is larger than 45, setting the BS to 1 and/or setting the maximum filter length of 2.
  • the at least one rule may include, when the QP of the current block is larger than the first threshold, setting the BS to 1 and/or setting the maximum filter length to 1.
  • the first threshold may be encoded in a bitstream or be predefined.
  • the first threshold may be encoded as a difference to a predetermined QP value.
  • the first threshold may be encoded in any one of a sequence parameter set, SPS, a picture parameter set, PPS, a slice header, a coding tree unit (CTU) syntax, or a coding unit (CU) syntax.
  • the current block may be an inter-coded block, and the sub-block edge may not be a transform unit (TU) boundary of the current block.
  • TU transform unit
  • the method according to the first embodiment may further comprise, in the case that motion vector refinement is not applied for the current block, determining, according to initial motion information of the current block, the at least one filtering related parameter associated with the sub-block edge.
  • the initial motion information of the current block may comprise one or more initial motion vectors of the first sub-block and/or the second sub-block.
  • the at least one filtering related parameter may be a boundary strength for deblocking the sub-block edge.
  • an encoder comprising processing circuitry for carrying out any one of the methods according to the first embodiment.
  • a decoder comprising processing circuitry for carrying out any one of the methods according to the first embodiment.
  • a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out any one of the methods according to the first embodiment.
  • a decoder comprising one or more processors, and a non-transitory computer-readable storage medium coupled to the one or more processors and storing instructions for execution by the one or more processors, wherein the instructions, when executed by the one or more processors, configure the decoder to carry out any one of the methods according to the first embodiment.
  • an encoder comprising one or more processors, and a non-transitory computer-readable storage medium coupled to the one or more processors and storing instructions for execution by the one or more processors, wherein the instructions, when executed by the one or more processors, configure the encoder to carry out any one of the methods according to the first embodiment.
  • a non-transitory computer-readable medium carrying a program code which, when executed by a computer device, causes the computer device to perform any one of the methods according to the first embodiment.
  • a second embodiment of the present disclosure provides a decoder or an encoder for coding a video sequence, comprising a determining unit configured to, in the case that motion vector refinement is enabled and/or applied for a current block, determine, according to at least one rule, at least one filtering related parameter associated with a sub-block edge between a first sub-block and a second sub-block of the current block; and a deblocking unit configured to perform deblocking filtering on the sub-block edge based on the at least one filtering related parameter, wherein the at least one rule is independent of refined motion information.
  • the at least one filtering related parameter may comprise a boundary strength (BS) for deblocking the sub-block edge. Additionally or alternatively, the at least one filtering related parameter may comprise a maximum filter length for deblocking the sub-block edge.
  • the maximum filter length may comprise a first maximum filter length for the first sub-block and a second maximum filter length for the second sub-block.
  • the performing deblocking filtering on the sub-block edge based on the at least one filtering related parameter may comprise modifying at most a number MA’ of sample values of the first sub-block as first output values, wherein the at most a number MA’ of the samples are in a line perpendicular to and adjacent to the sub-block edge, and modifying at most a number MB’ of sample values of the second sub-block as second output values, wherein the at most a number MB’ of the samples are in a line perpendicular to and adjacent to the sub-block edge, wherein MA’ is associated with the first maximum filter length, and MB’ is associated with the second maximum filter length.
  • MA’ may represent the first maximum filter length and MB’ may represent the second maximum filter length.
  • the at least one rule may be defined according to a quantization parameter (QP) of the current block.
  • QP quantization parameter
  • the determining the at least one filtering related parameter may comprise setting the BS for deblocking the sub-block edge to a predetermined value according to the at least one rule.
  • the determining the at least one filtering related parameter may comprise setting the maximum filter length for deblocking the sub-block edge to a predetermined value according to the at least one rule.
  • the determining unit may further be configured to compare the QP of the current block with a first threshold, wherein the at least one rule includes, when the QP of the current block is larger than the first threshold, then a value of the BS is set to a first BS value, and/or a value of the maximum filter length is set to a first length value.
  • the determining unit may further be configured to compare the QP of the current block with a first range of values, wherein the at least one rule includes, when the QP of the current block lies in the first range of values, then a value of the BS is set to a second BS value, and/or a value of the maximum filter length is set to a second length value.
  • the at least one rule may further include, when the QP of the current block is not larger than the first threshold and/or the QP of the current block does not lie in the first range of values, then a value of the BS is determined according to one or more initial motion vectors of the first sub-block and/or the second sub-block.
  • the at least one rule may include, when the QP of the current block is larger than 45, setting the BS to 1 and/or setting the maximum filter length to 3.
  • the at least one rule may include, when the QP of the current block is larger than 45, setting the BS to 1 and/or setting the maximum filter length to 1.
  • the at least one rule may include, when the QP of the current block is larger than 40, setting the BS to 1 and/or setting the maximum filter length to 1.
  • the at least one rule may include, when the QP of the current block is larger than 45, setting the BS to 1 and/or setting the maximum filter length of 2.
  • the at least one rule may include, when the QP of the current block is larger than the first threshold, setting the BS to 1 and/or setting the maximum filter length to 1.
  • the first threshold may be encoded in a bitstream or be predefined.
  • the first threshold may be encoded as a difference to a predetermined QP value.
  • the first threshold may be encoded in any one of a sequence parameter set, SPS, a picture parameter set, PPS, a slice header, a coding tree unit (CTU) syntax, or a coding unit (CU) syntax.
  • the current block may be an inter-coded block, and the sub-block edge may not be a transform unit (TU) boundary of the current block.
  • TU transform unit
  • the determining unit may further be configured to, in the case that motion vector refinement is not applied for the current block, determine, according to initial motion information of the current block, the at least one filtering related parameter associated with the sub-block edge.
  • the initial motion information of the current block may comprise one or more initial motion vectors of the first sub-block and/or the second sub-block.
  • the at least one filtering related parameter may be a boundary strength for deblocking the sub-block edge.
  • the methods according to the first embodiment of the disclosure can be performed by the apparatus according to the second embodiment of the disclosure. Further features and implementation forms of the methods according to the first embodiment of the disclosure correspond to the features and implementation forms of the apparatus according to the second embodiment of the disclosure.
  • a video encoding apparatus for encoding a picture of a video stream may comprise:
  • a reconstruction unit (214) configured to reconstruct the picture
  • a filter apparatus (220) as described below for processing the reconstructed picture into a filtered reconstructed picture.
  • a video decoding apparatus for decoding a picture of an encoded video stream may comprise:
  • a reconstruction unit (314) configured to reconstruct the picture
  • a loop filter apparatus (320) as described below for processing the reconstructed picture into a filtered reconstructed picture.
  • the filter apparatus may include a processor configured to carry out the filtering and modifying. Further, this also may ensure that especially internal sub-block edges between sub-blocks of a current block which DMVR is applied to can be deblocked in an efficient way.
  • FIG. 1A is a block diagram showing an example of a video coding system configured to implement embodiments of the disclosure
  • FIG. 1B is a block diagram showing another example of a video coding system configured to implement embodiments of the disclosure
  • FIG. 2 is a block diagram showing an example of a video encoder configured to implement embodiments of the disclosure
  • FIG. 3 is a block diagram showing an example structure of a video decoder configured to implement embodiments of the disclosure
  • FIG. 4 is a block diagram illustrating an example of an encoding apparatus or a decoding apparatus
  • FIG. 5 is a block diagram illustrating another example of an encoding apparatus or a decoding apparatus
  • FIG. 6 is a block diagram illustrating the processing order of the deblocking filter as horizontal filtering for vertical edges first, followed by vertical filtering for horizontal edges;
  • FIG. 7 shows a flow diagram depicting an exemplary process for increasing the efficiency of deblocking filtering
  • FIG. 8 shows a first embodiment of the deblocking filter device according to embodiments of the disclosure.
  • FIG. 9 shows exemplary sub-blocks inside the coding block in which DMVR is applied for the coding block in which each of these sub-blocks uses separate motion vectors.
  • FIG. 10 is a block diagram showing an example structure of a content supply system which realizes a content delivery service.
  • FIG. 11 is a block diagram showing a structure of an example of a terminal device.
  • FIG. 12 shows a flowchart for a method for deblocking a sub-block edge according to an embodiment of the disclosure.
  • FIG. 13 shows a block diagram illustrating an example of an encoding/decoding apparatus according to an embodiment of the disclosure.
  • ⁇ coding block An MxN block of samples for some values of M and N such that the division of a CTB into coding blocks is a partitioning.
  • ⁇ coding tree block An LxL block of samples for some value of N such that the division of a component into CTBs is a partitioning.
  • ⁇ coding tree unit A CTB of luma samples, two corresponding CTBs of chroma samples of a picture that has three sample arrays, or a CTB of samples of a monochrome picture or a picture that is coded using three separate colour planes and syntax structures used to code the samples.
  • ⁇ coding unit A coding block of luma samples, two corresponding coding blocks of chroma samples of a picture that has three sample arrays, or a coding block of samples of a monochrome picture or a picture that is coded using three separate colour planes and syntax structures used to code the samples.
  • ⁇ component An array or single sample from one of the three arrays (luma and two chroma) that compose a picture in 4: 2: 0, 4: 2: 2, or 4: 4: 4 colour format or the array or a single sample of the array that compose a picture in monochrome format.
  • a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa.
  • a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps) , even if such one or more units are not explicitly described or illustrated in the figures.
  • a specific apparatus is described based on one or a plurality of units, e.g.
  • a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units) , even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless specifically noted otherwise.
  • Video coding typically refers to the processing of a sequence of pictures, which form the video or video sequence. Instead of the term “picture” , the term “frame” or “image” may be used as synonyms in the field of video coding.
  • Video coding (or coding in general) comprises two parts: video encoding and video decoding.
  • Video encoding is performed at the source side, typically comprising processing (e.g. by compression) the original video pictures to reduce the amount of data required for representing the video pictures (for more efficient storage and/or transmission) .
  • Video decoding is performed at the destination side and typically comprises the inverse processing compared to the encoder to reconstruct the video pictures.
  • Embodiments referring to “coding” of video pictures shall be understood to relate to “encoding” or “decoding” of video pictures or respective video sequences.
  • the combination of the encoding part and the decoding part is also referred to as CODEC (Coding and Decoding) .
  • the original video pictures can be reconstructed, i.e. the reconstructed video pictures have the same quality as the original video pictures (assuming no transmission loss or other data loss occurs during storage or transmission) .
  • further compression e.g. by quantization, is performed, to reduce the amount of data representing the video pictures, which cannot be completely reconstructed at the decoder, i.e. the quality of the reconstructed video pictures is lower or worse compared to the quality of the original video pictures.
  • Video coding standards belong to the group of “lossy hybrid video codecs” (i.e. combine spatial and temporal prediction in the sample domain and 2D transform coding for applying quantization in the transform domain) .
  • Each picture of a video sequence is typically partitioned into a set of non-overlapping blocks and the coding is typically performed on a block level.
  • the video is typically processed, i.e. encoded, on a block (video block) level, e.g.
  • the encoder duplicates the decoder processing loop such that both will generate identical predictions (e.g. intra-and inter predictions) and/or re-constructions for processing, i.e. coding, the subsequent blocks.
  • a video encoder 20 and a video decoder 30 are described based on Figs. 1 to 3.
  • Fig. 1A is a schematic block diagram illustrating an example coding system 10, e.g. a video coding system 10 (or short coding system 10) that may utilize techniques of this present application.
  • Video encoder 20 (or short encoder 20) and video decoder 30 (or short decoder 30) of video coding system 10 represent examples of devices that may be configured to perform techniques in accordance with various examples described in the present application.
  • the coding system 10 comprises a source device 12 configured to provide encoded picture data 21 e.g. to a destination device 14 for decoding the encoded picture data 13.
  • the source device 12 comprises an encoder 20, and may additionally, i.e. optionally, comprise a picture source 16, a pre-processor (or pre-processing unit) 18, e.g. a picture pre-processor 18, and a communication interface or communication unit 22.
  • the picture source 16 may comprise or be any kind of picture capturing device, for example a camera for capturing a real-world picture, and/or any kind of a picture generating device, for example a computer-graphics processor for generating a computer animated picture, or any kind of other device for obtaining and/or providing a real-world picture, a computer generated picture (e.g. a screen content, a virtual reality (VR) picture) and/or any combination thereof (e.g. an augmented reality (AR) picture) .
  • the picture source may be any kind of memory or storage storing any of the aforementioned pictures.
  • the picture or picture data 17 may also be referred to as raw picture or raw picture data 17.
  • Pre-processor 18 may be configured to receive the (raw) picture data 17 and to perform pre-processing on the picture data 17 to obtain a pre-processed picture 19 or pre-processed picture data 19. Pre-processing performed by the pre-processor 18 may, e.g., comprise trimming, color format conversion (e.g. from RGB to YCbCr) , color correction, or de-noising. It can be understood that the pre-processing unit 18 may be an optional component.
  • the video encoder 20 may be configured to receive the pre-processed picture data 19 and provide encoded picture data 21 (further details will be described below, e.g., based on Fig. 2) .
  • Communication interface 22 of the source device 12 may be configured to receive the encoded picture data 21 and to transmit the encoded picture data 21 (or any further processed version thereof) over communication channel 13 to another device, e.g. the destination device 14 or any other device, for storage or direct reconstruction.
  • the destination device 14 comprises a decoder 30 (e.g. a video decoder 30) , and may additionally, i.e. optionally, comprise a communication interface or communication unit 28, a post-processor 32 (or post-processing unit 32) and a display device 34.
  • a decoder 30 e.g. a video decoder 30
  • the communication interface 28 of the destination device 14 may be configured to receive the encoded picture data 21 (or any further processed version thereof) , e.g. directly from the source device 12 or from any other source, e.g. a storage device, such as an encoded picture data storage device, and provide the encoded picture data 21 to the decoder 30.
  • a storage device such as an encoded picture data storage device
  • the communication interface 22 and the communication interface 28 may be configured to transmit or receive the encoded picture data 21 or encoded data 13 via a direct communication link between the source device 12 and the destination device 14, e.g. a direct wired or wireless connection, or via any kind of network, e.g. a wired or wireless network or any combination thereof, or any kind of private and public network, or any kind of combination thereof.
  • the communication interface 22 may be configured to package the encoded picture data 21 into an appropriate format, e.g. packets, and/or process the encoded picture data using any kind of transmission encoding or processing for transmission over a communication link or communication network.
  • the communication interface 28, forming the counterpart of the communication interface 22, may be configured to receive the transmitted data and process the transmission data using any kind of corresponding transmission decoding or processing and/or de-packaging to obtain the encoded picture data 21.
  • Both, communication interface 22 and communication interface 28 may be configured as unidirectional communication interfaces as indicated by the arrow for the communication channel 13 in Fig. 1A pointing from the source device 12 to the destination device 14, or as bi-directional communication interfaces, and may be configured to send and receive messages, e.g. to set up a connection, to acknowledge and exchange any other information related to the communication link and/or data transmission, such as encoded picture data transmission.
  • the decoder 30 may be configured to receive the encoded picture data 21 and provide decoded picture data 31 or a decoded picture 31 (further details will be described below, e.g., based on Fig. 3 or Fig. 5) .
  • the post-processor 32 of destination device 14 may be configured to post-process the decoded picture data 31 (also called reconstructed picture data) , e.g. the decoded picture 31, to obtain post-processed picture data 33, such as a post-processed picture 33.
  • the post-processing performed by the post-processing unit 32 may comprise any one or more of color format conversion (e.g. from YCbCr to RGB) , color correction, trimming, or re-sampling, or any other processing, e.g. for preparing the decoded picture data 31 for display, e.g. by display device 34.
  • the display device 34 of the destination device 14 may be configured to receive the post-processed picture data 33 for displaying the picture, e.g. to a user or viewer.
  • the display device 34 may be or comprise any kind of display for representing the reconstructed picture, such as an integrated or external display or monitor.
  • the display may be a liquid crystal displays (LCD) , an organic light emitting diodes (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS) , a digital light processor (DLP) or any kind of other display.
  • Fig. 1A depicts the source device 12 and the destination device 14 as separate devices
  • embodiments of devices may also comprise both devices or both functionalities, i.e. the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality.
  • the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality may be implemented using the same hardware and/or software or by separate hardware and/or software or any combination thereof.
  • the encoder 20 (e.g. a video encoder 20) or the decoder 30 (e.g. a video decoder 30) or both, encoder 20 and decoder 30 may be implemented via processing circuitry as shown in Fig. 1B, such as one or more microprocessors, digital signal processors (DSPs) , application-specific integrated circuits (ASICs) , field-programmable gate arrays (FPGAs) , discrete logic, hardware, video coding dedicated or any combinations thereof.
  • the encoder 20 may be implemented via processing circuitry 46 to embody the various modules as discussed with respect to encoder 20 of Fig. 2 and/or any other encoder system or subsystem described herein.
  • the decoder 30 may be implemented via processing circuitry 46 to embody the various modules as discussed with respect to decoder 30 of Fig. 3 and/or any other decoder system or subsystem described herein.
  • the processing circuitry may be configured to perform the various operations as discussed later.
  • a device may store instructions for the software in a suitable, non-transitory computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the techniques of this disclosure.
  • Video encoder 20 and video decoder 30 may be integrated as part of a combined encoder/decoder (CODEC) in a single device, for example, as shown in Fig. 1B.
  • CDEC combined encoder/decoder
  • the video coding system 40 shown in Fig. 1B comprises a processing circuitry implementing both a video encoder 20 and a video decoder 30.
  • one or more imaging devices 41 such as a camera for capturing real-world pictures
  • an antenna 42 such as a Bluetooth connection
  • one or more memory stores 44 such as a Wi-Fi connection
  • processors 43 such as a graphics processing unit (GPU)
  • a display device 45 such as a display device 34 described above, may be provided as part of the video coding system 40.
  • Source device 12 and destination device 14 may comprise any of a wide range of devices, including any kind of handheld or stationary devices, e.g. notebook or laptop computers, mobile phones, smart phones, tablets or tablet computers, cameras, desktop computers, set-top boxes, televisions, display devices, digital media players, video gaming consoles, video streaming devices (such as content services servers or content delivery servers) , broadcast receiver devices, broadcast transmitter devices, or the like and may use no or any kind of operating system.
  • the source device 12 and the destination device 14 may be equipped for wireless communication.
  • the source device 12 and the destination device 14 may be wireless communication devices.
  • video coding system 10 illustrated in Fig. 1A is merely an example and the techniques of the present application may apply to video coding systems (e.g., video encoding or video decoding) that do not necessarily include any data communication between the encoding and decoding devices.
  • data is retrieved from a local memory, streamed over a network, or the like.
  • a video encoding device may encode and store data in memory, and/or a video decoding device may retrieve and decode data from memory.
  • the encoding and decoding is performed by devices that do not communicate with one another, but simply encode data to memory and/or retrieve and decode data from memory.
  • HEVC High-Efficiency Video Coding
  • VVC Versatile Video coding
  • JCT-VC Joint Collaboration Team on Video Coding
  • VCEG ITU-T Video Coding Experts Group
  • MPEG ISO/IEC Motion Picture Experts Group
  • Fig. 2 shows a schematic block diagram of an example video encoder 20 that is configured to implement the techniques of the present application.
  • the video encoder 20 comprises an input 201 (or input interface 201) , a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, and an inverse transform processing unit 212, a reconstruction unit 214, a loop filter unit 220, a decoded picture buffer (DPB) 230, a mode selection unit 260, an entropy encoding unit 270 and an output 272 (or output interface 272) .
  • the mode selection unit 260 may include an inter prediction unit 244, an intra prediction unit 254 and a partitioning unit 262.
  • the inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown) .
  • a video encoder 20 as shown in Fig. 2 may also be referred to as a hybrid video encoder or a video encoder according to a hybrid video codec.
  • the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, and the mode selection unit 260 may be referred to as forming a forward signal path of the encoder 20, whereas the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244 and the intra-prediction unit 254 may be referred to as forming a backward signal path of the video encoder 20, wherein the backward signal path of the video encoder 20 corresponds to the signal path of the decoder (see video decoder 30 in Fig. 3) .
  • the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244 and the intra-prediction unit 254 are also referred to forming the “built-in decoder” of video encoder 20.
  • the encoder 20 may be configured to receive, e.g. via input 201, a picture 17 (or picture data 17) , e.g. a picture of a sequence of pictures forming a video or video sequence.
  • the received picture or picture data may also be a pre-processed picture 19 (or pre-processed picture data 19) .
  • the picture 17 may also be referred to as a current picture or a picture to be coded (in particular, in video coding to distinguish the current picture from other pictures, e.g. previously encoded and/or decoded pictures of the same video sequence, i.e. the video sequence which also comprises the current picture) .
  • a (digital) picture is or can be regarded as a two-dimensional array or matrix of samples with intensity values.
  • a sample in the array may also be referred to as pixel (short form of picture element) or a pel.
  • the number of samples in the horizontal and vertical direction (or axis) of the array or picture defines the size and/or resolution of the picture.
  • typically three color components are employed, i.e. the picture may be represented as or include three sample arrays.
  • RBG format or color space a picture comprises a corresponding red, green and blue sample array.
  • each pixel is typically represented in a luminance and chrominance format or color space, e.g.
  • YCbCr which comprises a luminance component indicated by Y (sometimes also L is used instead) and two chrominance components indicated by Cb and Cr.
  • the luminance (or short luma) component Y represents the brightness or grey level intensity (e.g. like in a grey-scale picture)
  • the two chrominance (or short chroma) components Cb and Cr represent the chromaticity or color information components.
  • a picture in YCbCr format comprises a luminance sample array of luminance sample values (Y) , and two chrominance sample arrays of chrominance values (Cb and Cr) .
  • Pictures in RGB format may be converted or transformed into YCbCr format and vice versa.
  • a picture is monochrome, the picture may comprise only a luminance sample array. Accordingly, a picture may be, for example, an array of luma samples in monochrome format or an array of luma samples and two corresponding arrays of chroma samples in 4: 2: 0, 4: 2: 2, and 4: 4: 4 colour format.
  • Embodiments of the video encoder 20 may comprise a picture partitioning unit (not depicted in Fig. 2) configured to partition the picture 17 into a plurality of (typically non-overlapping) picture blocks 203. These blocks may also be referred to as root blocks, macro blocks (H. 264/AVC) or coding tree blocks (CTB) or coding tree units (CTU) (according to H. 265/HEVC and VVC) .
  • the picture partitioning unit may be configured to use the same block size for all pictures of a video sequence and the corresponding grid defining the block size, or to change the block size between pictures or subsets or groups of pictures, and partition each picture into the corresponding blocks.
  • the video encoder may be configured to receive directly a block 203 of the picture 17, e.g. one, several or all blocks forming the picture 17.
  • the picture block 203 may also be referred to as current picture block or picture block to be coded.
  • the picture block 203 is or can be regarded as a two-dimensional array or matrix of samples with intensity values (sample values) , although of smaller dimension than the picture 17.
  • the block 203 may comprise, e.g., one sample array (e.g. a luma array in case of a monochrome picture 17, or a luma or chroma array in case of a color picture) or three sample arrays (e.g. a luma and two chroma arrays in case of a color picture 17) or any other number and/or kind of arrays depending on the color format applied.
  • the number of samples in the horizontal and vertical direction (or axis) of the block 203 defines the size of the block 203.
  • a block may, for example, comprise an M ⁇ N (M-column by N-row) array of samples, or an M ⁇ N array of transform coefficients.
  • Embodiments of the video encoder 20 as shown in Fig. 2 may be configured to encode the picture 17 block by block, e.g. the encoding and prediction is performed per block 203.
  • Embodiments of the video encoder 20 as shown in Fig. 2 may be further configured to partition and/or encode the picture by using slices (also referred to as video slices) , wherein a picture may be partitioned into or encoded using one or more slices (typically non-overlapping) , and each slice may comprise one or more blocks (e.g. CTUs) or one or more groups of blocks (e.g. tiles (H. 265/HEVC and VVC) or bricks (VVC) ) .
  • slices also referred to as video slices
  • each slice may comprise one or more blocks (e.g. CTUs) or one or more groups of blocks (e.g. tiles (H. 265/HEVC and VVC) or bricks (VVC) ) .
  • Embodiments of the video encoder 20 as shown in Fig. 2 may be further configured to partition and/or encode the picture by using slices/tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles) , wherein a picture may be partitioned into or encoded using one or more slices/tile groups (typically non-overlapping) , and each slice/tile group may comprise one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile may be of rectangular shape and may comprise one or more blocks (e.g. CTUs) , e.g. complete or fractional blocks.
  • slices/tile groups also referred to as video tile groups
  • tiles also referred to as video tiles
  • each slice/tile group may comprise one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile may be of rectangular shape and may comprise one or more blocks (e.g. CTUs) , e.g. complete or fractional blocks.
  • the residual calculation unit 204 may be configured to calculate a residual block 205 (also referred to as residual 205) based on the picture block 203 and a prediction block 265 (further details about the prediction block 265 are provided later) , e.g. by subtracting sample values of the prediction block 265 from sample values of the picture block 203, sample by sample (pixel by pixel) to obtain the residual block 205 in the sample domain.
  • a residual block 205 also referred to as residual 205
  • a prediction block 265 further details about the prediction block 265 are provided later
  • the transform processing unit 206 may be configured to apply a transform, such as a discrete cosine transform (DCT) or discrete sine transform (DST) , on the sample values of the residual block 205 to obtain transform coefficients 207 in a transform domain.
  • a transform such as a discrete cosine transform (DCT) or discrete sine transform (DST)
  • DCT discrete cosine transform
  • DST discrete sine transform
  • the transform coefficients 207 may also be referred to as transform residual coefficients and represent the residual block 205 in the transform domain.
  • the transform processing unit 206 may be configured to apply integer approximations of DCT/DST, such as the transforms specified for H. 265/HEVC. Compared to an orthogonal DCT transform, such integer approximations are typically scaled by a certain factor. In order to preserve the norm of the residual block which is processed by forward and inverse transforms, additional scaling factors are applied as part of the transform process.
  • the scaling factors are typically chosen based on certain constraints like scaling factors being a power of two for shift operations, bit depth of the transform coefficients, tradeoff between accuracy and implementation costs, etc. Specific scaling factors are, for example, specified for the inverse transform, e.g. by inverse transform processing unit 212 (and the corresponding inverse transform, e.g. by inverse transform processing unit 312 at video decoder 30) and corresponding scaling factors for the forward transform, e.g. by transform processing unit 206, at an encoder 20 may be specified accordingly.
  • Embodiments of the video encoder 20 may be configured to output transform parameters, e.g. a type of transform or transforms, e.g. directly or encoded or compressed via the entropy encoding unit 270, so that, e.g., the video decoder 30 may receive and use the transform parameters for decoding.
  • transform parameters e.g. a type of transform or transforms, e.g. directly or encoded or compressed via the entropy encoding unit 270, so that, e.g., the video decoder 30 may receive and use the transform parameters for decoding.
  • the quantization unit 208 may be configured to quantize the transform coefficients 207 to obtain quantized coefficients 209, e.g. by applying scalar quantization or vector quantization.
  • the quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.
  • the quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, an n-bit transform coefficient may be rounded down to an m-bit transform coefficient during quantization, where n is greater than m.
  • the degree of quantization may be modified by adjusting a quantization parameter (QP) .
  • QP quantization parameter
  • different scalings may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, whereas larger quantization step sizes correspond to coarser quantization.
  • the applicable quantization step size may be indicated by a quantization parameter (QP) .
  • the quantization parameter may, for example, be an index of a predefined set of applicable quantization step sizes.
  • small quantization parameters may correspond to fine quantization (small quantization step sizes) and large quantization parameters may correspond to coarse quantization (large quantization step sizes) or vice versa.
  • the quantization may include division by a quantization step size and a corresponding and/or the inverse dequantization, e.g. by inverse quantization unit 210, may include multiplication by the quantization step size.
  • Embodiments according to some standards, e.g. HEVC may be configured to use a quantization parameter to determine the quantization step size.
  • the quantization step size may be calculated based on a quantization parameter using a fixed point approximation of an equation including division.
  • Additional scaling factors may be introduced for quantization and dequantization to restore the norm of the residual block, which might get modified because of the scaling used in the fixed point approximation of the equation for quantization step size and quantization parameter.
  • the scaling of the inverse transform and dequantization might be combined.
  • customized quantization tables may be used and signaled from an encoder to a decoder, e.g. in a bitstream.
  • the quantization is a lossy operation, wherein the loss increases with increasing quantization step sizes.
  • Embodiments of the video encoder 20 may be configured to output quantization parameters (QPs) , e.g. directly or encoded via the entropy encoding unit 270, so that, e.g., the video decoder 30 may receive and apply the quantization parameters for decoding.
  • QPs quantization parameters
  • the inverse quantization unit 210 is configured to apply the inverse quantization of the quantization unit 208 on the quantized coefficients to obtain dequantized coefficients 211, e.g. by applying the inverse of the quantization scheme applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208.
  • the dequantized coefficients 211 may also be referred to as dequantized residual coefficients 211 and correspond -although typically not identical to the transform coefficients due to the loss by quantization -to the transform coefficients 207.
  • the inverse transform processing unit 212 is configured to apply the inverse transform of the transform applied by the transform processing unit 206, e.g. an inverse discrete cosine transform (DCT) or inverse discrete sine transform (DST) or other inverse transforms, to obtain a reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample domain.
  • the reconstructed residual block 213 may also be referred to as a transform block 213.
  • the reconstruction unit 214 (e.g. adder or summer 214) is configured to add the transform block 213 (i.e. reconstructed residual block 213) to the prediction block 265 to obtain a reconstructed block 215 in the sample domain, e.g. by adding –sample by sample -the sample values of the reconstructed residual block 213 and the sample values of the prediction block 265.
  • the loop filter unit 220 (or short “loop filter” 220) , is configured to filter the reconstructed block 215 to obtain a filtered block 221, or in general, to filter reconstructed samples to obtain filtered samples.
  • the loop filter unit may be configured to smooth pixel transitions, or otherwise improve the video quality.
  • the loop filter unit 220 may comprise one or more loop filters such as a de-blocking filter, a sample-adaptive offset (SAO) filter or one or more other filters, such as an adaptive loop filter (ALF) , a noise suppression filter (NSF) , or any combination thereof.
  • the loop filter unit 220 may comprise a deblocking filter, an SAO filter and an ALF filter.
  • the order of the filtering process may be the deblocking filter, SAO and ALF.
  • a process called luma mapping with chroma scaling (LMCS) namely, the adaptive in-loop reshaper
  • LMCS luma mapping with chroma scaling
  • This process is performed before deblocking.
  • the deblocking filter process may be also applied to internal sub-block edges, e.g. affine sub-block edges, ATMVP sub-blocks edge, sub-block transform (SBT) edges and intra sub-partition (ISP) edges.
  • the loop filter unit 220 is shown in Fig. 2 as being an in-loop filter, in other configurations, the loop filter unit 220 may be implemented as a post loop filter.
  • the filtered block 221 may also be referred to as a filtered reconstructed block 221.
  • the present disclosure provides a deblocking filter for sub-block edges for inter-predicted blocks wherein deblocking can be performed in parallel to a motion vector refinement process such as a decoder side motion vector refinement.
  • Embodiments of the video encoder 20 may be configured to output loop filter parameters (such as SAO filter parameters or ALF filter parameters or LMCS parameters) , e.g. directly or encoded via the entropy encoding unit 270, so that, e.g., a decoder 30 may receive and apply the same loop filter parameters or respective loop filters for decoding.
  • loop filter parameters such as SAO filter parameters or ALF filter parameters or LMCS parameters
  • the decoded picture buffer (DPB) 230 may be a memory that stores reference pictures, or in general reference picture data, for encoding video data by video encoder 20.
  • the DPB 230 may be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM) , including synchronous DRAM (SDRAM) , magnetoresistive RAM (MRAM) , resistive RAM (RRAM) , or other types of memory devices.
  • DRAM dynamic random access memory
  • SDRAM synchronous DRAM
  • MRAM magnetoresistive RAM
  • RRAM resistive RAM
  • the decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221.
  • the decoded picture buffer 230 may be further configured to store other previously filtered blocks, e.g. previously reconstructed and filtered blocks 221, of the same current picture or of different pictures, e.g.
  • the decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215, or in general unfiltered reconstructed samples, e.g. if the reconstructed block 215 is not filtered by loop filter unit 220, or any other further processed version of the reconstructed blocks or samples.
  • the mode selection unit 260 comprises partitioning unit 262, inter-prediction unit 244 and intra-prediction unit 254, and is configured to receive or obtain original picture data, such as an original block 203 (current block 203 of the current picture 17) , and reconstructed picture data, such as filtered and/or unfiltered reconstructed samples or blocks of the same (current) picture and/or from one or a plurality of previously decoded pictures, e.g. from decoded picture buffer 230 or other buffers (e.g. line buffer, not shown) .
  • the reconstructed picture data is used as reference picture data for prediction, e.g. inter-prediction or intra-prediction, to obtain a prediction block 265 or predictor 265.
  • Mode selection unit 260 may be configured to determine or select a partitioning for a current block prediction mode (including no partitioning) and a prediction mode (e.g. an intra-or inter-prediction mode) and generate a corresponding prediction block 265, which is used for the calculation of the residual block 205 and for the reconstruction of the reconstructed block 215.
  • a prediction mode e.g. an intra-or inter-prediction mode
  • Embodiments of the mode selection unit 260 may be configured to select the partitioning and the prediction mode (e.g. from those supported by or available for mode selection unit 260) , which provide the best match or in other words the minimum residual (minimum residual means better compression for transmission or storage) , or a minimum signaling overhead (minimum signaling overhead means better compression for transmission or storage) , or which considers or balances both.
  • the mode selection unit 260 may be configured to determine the partitioning and prediction mode based on rate distortion optimization (RDO) , i.e. select the prediction mode which provides a minimum rate distortion. Terms like “best” , “minimum” , “optimum” etc.
  • the partitioning unit 262 may be configured to partition a picture from a video sequence into a sequence of coding tree units (CTUs) and the CTU 203 may be further partitioned into smaller block partitions or sub-blocks (which again form blocks) , e.g. iteratively using quad-tree-partitioning (QT) , binary-tree partitioning (BT) or triple-tree-partitioning (TT) or any combination thereof, and to perform the prediction for each of the block partitions or sub-blocks, wherein the mode selection comprises the selection of the tree-structure of the partitioned block 203 and the prediction modes are applied to each of the block partitions or sub-blocks.
  • QT quad-tree-partitioning
  • BT binary-tree partitioning
  • TT triple-tree-partitioning
  • partitioning e.g. by partitioning unit 262
  • prediction processing by inter-prediction unit 244 and intra-prediction unit 254
  • the partitioning unit 262 may be configured to partition a picture from a video sequence into a sequence of coding tree units (CTUs) , and the partitioning unit 262 may partition (or split) a coding tree unit (CTU) 203 into smaller partitions, e.g. smaller blocks of square or rectangular size.
  • a CTU includes an N ⁇ N block of luma samples together with two corresponding blocks of chroma samples.
  • the maximum allowed size of the luma block in a CTU is specified to be 128 ⁇ 128 in the current versatile video coding (VVC) specification, but it may be specified to be value different from 128x128 in the future, for example, 256x256.
  • the CTUs of a picture may be clustered/grouped as slices/tile groups, tiles or bricks.
  • a tile covers a rectangular region of a picture, and a tile can be divided into one or more bricks.
  • a brick consists of a number of CTU rows within a tile.
  • a tile that is not partitioned into multiple bricks can be referred to as a brick.
  • a brick is a true subset of a tile and is not referred to as a tile.
  • a slice/tile group contains a sequence of tiles in tile raster scan of a picture.
  • the rectangular slice mode a slice contains a number of bricks of a picture that collectively form a rectangular region of the picture.
  • the bricks within a rectangular slice are in the order of brick raster scan of the slice.
  • the smaller blocks may be further partitioned into even smaller partitions.
  • This is also referred to as tree-partitioning or hierarchical tree-partitioning, wherein a root block, e.g. at root tree-level 0 (hierarchy-level 0, depth 0) , may be recursively partitioned, e.g. partitioned into two or more blocks of a next lower tree-level, e.g. nodes at tree-level 1 (hierarchy-level 1, depth 1) , wherein these blocks may be again partitioned into two or more blocks of a next lower level, e.g. tree-level 2 (hierarchy-level 2, depth 2) , etc.
  • Blocks which are not further partitioned are also referred to as leaf-blocks or leaf nodes of the tree.
  • a tree using partitioning into two partitions is referred to as a binary-tree (BT)
  • BT binary-tree
  • TT ternary-tree
  • QT quad-tree
  • a coding tree unit may be or comprise a CTB of luma samples and two corresponding CTBs of chroma samples of a picture that has three sample arrays, or a CTB of samples of a monochrome picture or a picture that is coded using three separate colour planes and syntax structures used to code the samples.
  • a coding tree block may be an N ⁇ N block of samples for some value of N such that the division of a component into CTBs is a partitioning.
  • a coding unit may be or comprise a coding block of luma samples and two corresponding coding blocks of chroma samples of a picture that has three sample arrays, or a coding block of samples of a monochrome picture or a picture that is coded using three separate colour planes and syntax structures used to code the samples.
  • a coding block may be an M ⁇ N block of samples for some values of M and N such that the division of a CTB into coding blocks is a partitioning.
  • a coding tree unit may be split into CUs by using a quad-tree structure denoted as a coding tree.
  • the decision whether to code a picture area using inter-picture (temporal) or intra-picture (spatial) prediction is made at the leaf CU level.
  • Each leaf CU can be further split into one, two or four PUs according to the PU splitting type. Inside one PU, the same prediction process is applied and the relevant information is transmitted to the decoder on a PU basis.
  • a leaf CU can be partitioned into transform units (TUs) according to another quad-tree structure similar to the coding tree for the CU.
  • a combined Quad-tree nested multi-type tree using binary and ternary splits segmentation structure is for example used to partition a coding tree unit.
  • a CU can have either a square or rectangular shape.
  • the coding tree unit (CTU) is first partitioned by a quaternary tree. Then the quaternary tree leaf nodes can be further partitioned by a multi-type tree structure.
  • the multi-type tree leaf nodes are called coding units (CUs) , and unless the CU is too large for the maximum transform length, this segmentation is used for prediction and transform processing without any further partitioning. This means that, in most cases, the CU, prediction units (PU) and transform units (TU) have the same block size in the quadtree with nested multi-type tree coding block structure. An exception occurs when the maximum supported transform length is smaller than the width or height of the colour component of the CU.
  • VVC develops a unique signaling mechanism of the partition splitting information in quadtree with nested multi-type tree coding tree structure.
  • a coding tree unit (CTU) is treated as the root of a quaternary tree and is first partitioned by a quaternary tree structure.
  • Each quaternary tree leaf node (when sufficiently large to allow it) is then further partitioned by a multi-type tree structure.
  • a first flag (mtt_split_cu_flag) is signalled to indicate whether the node is further partitioned; when a node is further partitioned, a second flag (mtt_split_cu_vertical_flag) is signalled to indicate the splitting direction, and then a third flag (mtt_split_cu_binary_flag) is signalled to indicate whether the split is a binary split or a ternary split.
  • the multi-type tree slitting mode (MttSplitMode) of a CU can be derived by a decoder based on a predefined rule or a table. It should be noted, for a certain design, for example, 64 ⁇ 64 Luma block and 32 ⁇ 32 Chroma pipelining design in VVC hardware decoders, TT split is forbidden when either width or height of a luma coding block is larger than 64. TT split is also forbidden when either width or height of a chroma coding block is larger than 32.
  • the pipelining design will divide a picture into Virtual pipeline data units (VPDUs) which are defined as non-overlapping units in a picture.
  • VPDUs Virtual pipeline data units
  • successive VPDUs are processed by multiple pipeline stages simultaneously.
  • the VPDU size is roughly proportional to the buffer size in most pipeline stages, so it is important to keep the VPDU size small.
  • the VPDU size can be set to the maximum transform block (TB) size.
  • TT ternary tree
  • BT binary tree partition
  • the tree node block when a portion of a tree node block exceeds the bottom or right picture boundary, the tree node block is forced to be split until all samples of every coded CU are located inside the picture boundaries.
  • the Intra Sub-Partitions (ISP) tool may divide luma intra-predicted blocks vertically or horizontally into 2 or 4 sub-partitions depending on the block size.
  • the mode selection unit 260 of video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.
  • the video encoder 20 is configured to determine or select the best or an optimum prediction mode from a set of (e.g. pre-determined) prediction modes.
  • the set of prediction modes may comprise intra-prediction modes and/or inter-prediction modes.
  • the set of intra-prediction modes may comprise 35 different intra-prediction modes, such as non-directional modes like DC (or mean) mode and planar mode, or directional modes, e.g. as defined in HEVC, or may comprise 67 different intra-prediction modes, such as non-directional modes like DC (or mean) mode and planar mode, or directional modes, e.g. as defined for VVC.
  • intra-prediction modes such as non-directional modes like DC (or mean) mode and planar mode, or directional modes, e.g. as defined for VVC.
  • several conventional angular intra prediction modes are adaptively replaced with wide-angle intra prediction modes for the non-square blocks, e.g. as defined in VVC.
  • to avoid division operations for DC prediction only the longer side is used to compute the average for non-square blocks.
  • the results of intra prediction of planar mode may be further modified by a position dependent intra prediction combination (PDPC) method.
  • PDPC position dependent intra prediction combination
  • the intra-prediction unit 254 is configured to use reconstructed samples of neighboring blocks of the same current picture to generate an (intra-) prediction block 265 according to an intra-prediction mode from the set of intra-prediction modes.
  • the intra-prediction unit 254 (or in general the mode selection unit 260) may be further configured to output intra-prediction parameters (or in general information indicative of the selected intra-prediction mode for the block) to the entropy encoding unit 270 in the form of syntax elements 266 for inclusion into the encoded picture data 21, so that, e.g., the video decoder 30 may receive and use the prediction parameters for decoding.
  • the set of (or possible) inter-prediction modes depends on the available reference pictures (i.e. previous, at least partially decoded pictures, e.g. stored in DBP 230) and other inter-prediction parameters, e.g. whether the whole reference picture or only a part, e.g. a search window area around the area of the current block, of the reference picture is used for searching for a best matching reference block, and/or e.g. whether pixel interpolation is applied, such as half/semi-pel, quarter-pel and/or 1/16 pel interpolation, or not.
  • other inter-prediction parameters e.g. whether the whole reference picture or only a part, e.g. a search window area around the area of the current block, of the reference picture is used for searching for a best matching reference block, and/or e.g. whether pixel interpolation is applied, such as half/semi-pel, quarter-pel and/or 1/16 pel interpolation, or not.
  • skip mode In addition to the above prediction modes, skip mode, direct mode and/or other inter prediction mode may be applied.
  • the merge candidate list of such a mode is constructed by including the following five types of candidates in order: Spatial MVP from spatial neighbor CUs, temporal MVP from co-located CUs, history-based MVP from a FIFO table, pairwise average MVP and Zero MVs.
  • a bilateral-matching based decoder-side motion vector refinement may be applied to increase the accuracy of the MVs of the merge mode.
  • Merge mode with MVD is a merge mode with motion vector differences (MVD) .
  • An MMVD flag is signaled right after sending a skip flag and merge flag to specify whether MMVD mode is used for a CU.
  • a CU-level adaptive motion vector resolution (AMVR) scheme may be applied. AMVR allows MVD of the CU to be coded in different precision. Dependent on the prediction mode for the current CU, the MVDs of the current CU can be adaptively selected.
  • the combined inter/intra prediction (CIIP) mode may be applied to the current CU. Weighted averaging of the inter and intra prediction signals is performed to obtain the CIIP prediction.
  • affine motion compensated prediction the affine motion field of the block is described by motion information of two control point (4-parameter) or three control point (6-parameter) motion vectors.
  • Sub-block-based temporal motion vector prediction (SbTMVP) is similar to the temporal motion vector prediction (TMVP) in HEVC, but predicts the motion vectors of the sub-CUs within the current CU.
  • Bi-directional optical flow (BDOF) , previously referred to as BIO, is a simpler version that requires much less computation, especially in terms of number of multiplications and the size of the multiplier.
  • BIO Bi-directional optical flow
  • a CU is split evenly into two triangle-shaped partitions, using either the diagonal split or the anti-diagonal split.
  • the bi-prediction mode is extended beyond simple averaging to allow weighted averaging of the two prediction signals.
  • the inter-prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (both not shown in Fig. 2) .
  • the motion estimation unit may be configured to receive or obtain the picture block 203 (current picture block 203 of the current picture 17) and a decoded picture 231, or at least one or a plurality of previously reconstructed blocks, such as reconstructed blocks of one or a plurality of previously decoded pictures 231, for motion estimation.
  • a video sequence may comprise the current picture and the previously decoded pictures 231, or in other words, the current picture and the previously decoded pictures 231 may be part of or form a sequence of pictures forming a video sequence.
  • the encoder 20 may be configured to select a reference block from a plurality of reference blocks of the same or different pictures of the plurality of previously decoded pictures and provide a reference picture (or reference picture index) and/or an offset (spatial offset) between the position (x, y coordinates) of the reference block and the position of the current block as inter-prediction parameters to the motion estimation unit.
  • This offset is also called motion vector (MV) .
  • the motion compensation unit may be configured to obtain, e.g. receive, an inter-prediction parameter and to perform inter-prediction based on or using the inter-prediction parameter to obtain an (inter-) prediction block 265.
  • Motion compensation performed by the motion compensation unit, may involve fetching or generating the prediction block based on the motion/block vector determined by motion estimation, possibly performing interpolations to sub-pixel precision. Interpolation filtering may generate additional pixel samples from known pixel samples, thus potentially increasing the number of candidate prediction blocks that may be used to code a picture block.
  • the motion compensation unit may locate the prediction block to which the motion vector points in one of the reference picture lists.
  • the motion compensation unit may also generate syntax elements associated with the blocks and video slices for use by video decoder 30 in decoding the picture blocks of the video slice.
  • syntax elements associated with the blocks and video slices for use by video decoder 30 in decoding the picture blocks of the video slice.
  • tile groups and/or tiles and respective syntax elements may be generated or used.
  • the entropy encoding unit 270 is configured to apply, for example, an entropy encoding algorithm or scheme (e.g. a variable length coding (VLC) scheme, a context adaptive VLC scheme (CAVLC) , an arithmetic coding scheme, a binarization, a context adaptive binary arithmetic coding (CABAC) , syntax-based context-adaptive binary arithmetic coding (SBAC) , probability interval partitioning entropy (PIPE) coding or another entropy encoding methodology or technique) or bypass (no compression) on the quantized coefficients 209, inter-prediction parameters, intra-prediction parameters, loop filter parameters and/or other syntax elements to obtain encoded picture data 21 which can be output via the output 272, e.g.
  • an entropy encoding algorithm or scheme e.g. a variable length coding (VLC) scheme, a context adaptive VLC scheme (CAVLC) , an arithmetic coding scheme
  • the encoded bitstream 21 may be transmitted to video decoder 30, or stored in a memory for later transmission or retrieval by video decoder 30.
  • a non-transform based encoder 20 can quantize the residual signal directly without the transform processing unit 206 for certain blocks or frames.
  • an encoder 20 can have the quantization unit 208 and the inverse quantization unit 210 combined into a single unit.
  • Fig. 3 shows an example of a video decoder 30 that is configured to implement the techniques of the present application.
  • the video decoder 30 is configured to receive encoded picture data 21 (e.g. encoded bitstream 21) , e.g. encoded by encoder 20, to obtain a decoded picture 331.
  • the encoded picture data or bitstream comprises information for decoding the encoded picture data, e.g. data that represents picture blocks of an encoded video slice (and/or tile group or tile) and associated syntax elements.
  • the decoder 30 comprises an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g. a summer 314) , a loop filter 320, a decoded picture buffer (DBP) 330, a mode application unit 360, an inter-prediction unit 344 and an intra-prediction unit 354.
  • Inter-prediction unit 344 may be or include a motion compensation unit.
  • Video decoder 30 may, in some examples, perform a decoding pass generally reciprocal to the encoding pass described with respect to video encoder 20 of Fig. 2.
  • the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter-prediction unit 244 and the intra-prediction unit 254 are also referred to as forming the “built-in decoder” of video encoder 20.
  • the inverse quantization unit 310 may be identical in function to the inverse quantization unit 210
  • the inverse transform processing unit 312 may be identical in function to the inverse transform processing unit 212
  • the reconstruction unit 314 may be identical in function to reconstruction unit 214
  • the loop filter 320 may be identical in function to the loop filter 220
  • the decoded picture buffer 330 may be identical in function to the decoded picture buffer 230. Therefore, the explanations provided for the respective units and functions of the video 20 encoder apply correspondingly to the respective units and functions of the video decoder 30.
  • the entropy decoding unit 304 is configured to parse the bitstream 21 (or in general encoded picture data 21) and perform, for example, entropy decoding to the encoded picture data 21 to obtain, e.g., quantized coefficients 309 and/or decoded coding parameters 366, such as any or all of inter-prediction parameters (e.g. reference picture index and motion vector) , intra-prediction parameters (e.g. intra-prediction mode or index) , transform parameters, quantization parameters, loop filter parameters, and/or other syntax elements.
  • Entropy decoding unit 304 may be configured to apply the decoding algorithms or schemes corresponding to the encoding schemes as described with regard to the entropy encoding unit 270 of the encoder 20.
  • Entropy decoding unit 304 may be further configured to provide inter-prediction parameters, intra-prediction parameters and/or other syntax elements to the mode application unit 360 and other parameters to other units of the decoder 30.
  • Video decoder 30 may receive the syntax elements at the video slice level and/or the video block level. In addition or as an alternative to slices and respective syntax elements, tile groups and/or tiles and respective syntax elements may be received and/or used.
  • the inverse quantization unit 310 may be configured to receive quantization parameters (QP) (or in general, information related to the inverse quantization) and quantized coefficients from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) and to apply, based on the quantization parameters, an inverse quantization to the decoded quantized coefficients 309 to obtain dequantized coefficients 311, which may also be referred to as transform coefficients 311.
  • the inverse quantization process may include use of a quantization parameter determined by video encoder 20 for each video block in the video slice (or tile or tile group) to determine a degree of quantization and, likewise, a degree of inverse quantization that should be applied.
  • Inverse transform processing unit 312 may be configured to receive dequantized coefficients 311, also referred to as transform coefficients 311, and to apply a transform to the dequantized coefficients 311 in order to obtain reconstructed residual blocks 313 in the sample domain.
  • the reconstructed residual blocks 313 may also be referred to as transform blocks 313.
  • the transform may be an inverse transform, e.g., an inverse DCT, an inverse DST, an inverse integer transform, or a conceptually similar inverse transform process.
  • the inverse transform processing unit 312 may be further configured to receive transform parameters or corresponding information from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) to determine the transform to be applied to the dequantized coefficients 311.
  • the reconstruction unit 314 (e.g. adder or summer 314) may be configured to add the reconstructed residual block 313, to the prediction block 365 to obtain a reconstructed block 315 in the sample domain, e.g. by adding the sample values of the reconstructed residual block 313 and the sample values of the prediction block 365.
  • the loop filter unit 320 (either in the coding loop or after the coding loop) is configured to filter the reconstructed block 315 to obtain a filtered block 321, e.g. to smooth pixel transitions, or otherwise improve the video quality.
  • the loop filter unit 320 may comprise one or more loop filters such as a deblocking filter, a sample-adaptive offset (SAO) filter or one or more other filters, e.g. an adaptive loop filter (ALF) , a noise suppression filter (NSF) , or any combination thereof.
  • the loop filter unit 220 may comprise a deblocking filter, an SAO filter and an ALF filter. The order of the filtering process may be the deblocking filter, SAO and ALF.
  • LMCS luma mapping with chroma scaling
  • SBT sub-block transform
  • ISP intra sub-partition
  • the present disclosure provides a deblocking filter for sub-block edges for inter-predicted blocks wherein deblocking can be performed in parallel to a motion vector refinement process such as a decoder side motion vector refinement.
  • the decoded video blocks 321 of a picture are then stored in the decoded picture buffer 330, which stores the decoded pictures 331 as reference pictures for subsequent motion compensation for other pictures and/or for output or respectively display.
  • the decoder 30 is configured to output the decoded picture 311, e.g. via output 312, for presentation or viewing to a user.
  • the inter-prediction unit 344 may be identical to the inter-prediction unit 244 (in particular, to the motion compensation unit) and the intra-prediction unit 354 may be identical to the intra-prediction unit 254 in function, and performs split or partitioning decisions and prediction based on the partitioning and/or prediction parameters or respective information received from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by entropy decoding unit 304) .
  • Mode application unit 360 may be configured to perform the prediction (intra-or inter-prediction) per block based on reconstructed pictures, blocks or respective samples (filtered or unfiltered) to obtain the prediction block 365.
  • intra-prediction unit 354 of mode application unit 360 is configured to generate prediction block 365 for a picture block of the current video slice based on a signaled intra-prediction mode and data from previously decoded blocks of the current picture.
  • inter-prediction unit 344 e.g. motion compensation unit
  • the prediction blocks may be produced from one of the reference pictures within one of the reference picture lists.
  • Video decoder 30 may construct the reference picture lists, List 0 and List 1, using default construction techniques based on reference pictures stored in DPB 330.
  • the same or similar approach may be applied for or by embodiments using tile groups (e.g. video tile groups) and/or tiles (e.g. video tiles) in addition or alternatively to slices (e.g. video slices) , e.g. a video may be coded using I, P or B tile groups and/or tiles.
  • Mode application unit 360 is configured to determine the prediction information for a video/picture block of the current video slice by parsing the motion vectors or related information and other syntax elements, and use the prediction information to produce the prediction blocks for the current video block being decoded. For example, the mode application unit 360 uses some of the received syntax elements to determine a prediction mode (e.g., intra-or inter-prediction) used to code the video blocks of the video slice, an inter-prediction slice type (e.g., B slice, P slice, or GPB slice) , construction information for one or more of the reference picture lists for the slice, motion vectors for each inter-coded video block of the slice, inter-prediction status for each inter-coded video block of the slice, and other information to decode the video blocks in the current video slice.
  • a prediction mode e.g., intra-or inter-prediction
  • an inter-prediction slice type e.g., B slice, P slice, or GPB slice
  • tile groups e.g. video tile groups
  • tiles e.g. video tiles
  • slices e.g. video slices
  • a video may be coded using I, P or B tile groups and/or tiles.
  • Embodiments of the video decoder 30 as shown in Fig. 3 may be configured to partition and/or decode the picture by using slices (also referred to as video slices) , wherein a picture may be partitioned into or decoded using one or more slices (typically non-overlapping) , and each slice may comprise one or more blocks (e.g. CTUs) or one or more groups of blocks (e.g. tiles (H. 265/HEVC and VVC) or bricks (VVC) ) .
  • slices also referred to as video slices
  • each slice may comprise one or more blocks (e.g. CTUs) or one or more groups of blocks (e.g. tiles (H. 265/HEVC and VVC) or bricks (VVC) ) .
  • Embodiments of the video decoder 30 as shown in Fig. 3 may be configured to partition and/or decode the picture by using slices/tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles) , wherein a picture may be partitioned into or decoded using one or more slices/tile groups (typically non- overlapping) , and each slice/tile group may comprise one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile may be of rectangular shape and may comprise one or more blocks (e.g. CTUs) , e.g. complete or fractional blocks.
  • slices/tile groups also referred to as video tile groups
  • tiles also referred to as video tiles
  • each slice/tile group may comprise one or more blocks (e.g. CTUs) or one or more tiles, wherein each tile may be of rectangular shape and may comprise one or more blocks (e.g. CTUs) , e.g. complete or fractional blocks.
  • the video decoder 30 can be used to decode the encoded picture data 21.
  • the decoder 30 can produce the output video stream without the loop filtering unit 320.
  • a non-transform based decoder 30 can inverse-quantize the residual signal directly without the inverse-transform processing unit 312 for certain blocks or frames.
  • the video decoder 30 can have the inverse-quantization unit 310 and the inverse-transform processing unit 312 combined into a single unit.
  • a processing result of a current step may be further processed and then output to the next step.
  • a further operation such as Clip or shift, may be performed on the processing result of the interpolation filtering, motion vector derivation or loop filtering.
  • the value of motion vector is constrained to a predefined range according to its representing bit. If the representing bit of a motion vector is bitDepth, then the range is -2 ⁇ (bitDepth-1) ⁇ 2 ⁇ (bitDepth-1) -1, where “ ⁇ ” means exponentiation. For example, if bitDepth is set equal to 16, the range is -32768 ⁇ 32767; if bitDepth is set equal to 18, the range is -131072 ⁇ 131071.
  • the value of the derived motion vector (e.g. the MVs of four 4x4 sub-blocks within one 8x8 block) is constrained such that the maximum difference between integer parts of the four 4x4 sub-block MVs is no more than N pixels, such as no more than 1 pixel.
  • Two methods are available for constraining the motion vector according to the bitDepth.
  • Fig. 4 is a schematic diagram of a video coding device 400 according to an embodiment of the present disclosure.
  • the video coding device 400 is suitable for implementing the disclosed embodiments as described below.
  • the video coding device 400 may be a decoder such as video decoder 30 of Fig. 1A or an encoder such as video encoder 20 of Fig. 1A.
  • the video coding device 400 may comprise ingress ports 410 (or input ports 410) and one or more receiver units (Rx) 420 for receiving data; a processor, logic unit, or central processing unit (CPU) 430 to process the data; one or more transmitter units (Tx) 440 and egress ports 450 (or output ports 450) for transmitting the data; and a memory 460 for storing the data.
  • the video coding device 400 may also comprise optical-to-electrical (OE) components and electrical-to-optical (EO) components coupled to the ingress ports 410, the receiver units 420, the transmitter units 440, and the egress ports 450 for egress or ingress of optical or electrical signals.
  • OE optical-to-electrical
  • EO electrical-to-optical
  • the processor 430 may be implemented by hardware and software.
  • the processor 430 may be implemented as one or more CPU chips, cores (e.g., as a multi-core processor) , FPGAs, ASICs, and DSPs.
  • the processor 430 may be in communication with the ingress ports 410, the receiver units 420, the transmitter units 440, egress ports 450, and the memory 460.
  • the processor 430 may comprise a coding module 470.
  • the coding module 470 implements the disclosed embodiments described above and below. For instance, the coding module 470 may implement, process, prepare, or provide the various coding operations.
  • the inclusion of the coding module 470 therefore provides a substantial improvement to the functionality of the video coding device 400 and effects a transformation of the video coding device 400 to a different state.
  • the coding module 470 may be implemented as instructions stored in the memory 460 and executed by the processor 430.
  • the memory 460 may comprise one or more disks, tape drives, and solid-state drives and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution.
  • the memory 460 may be, for example, volatile and/or non-volatile and may be a read-only memory (ROM) , random access memory (RAM) , ternary content-addressable memory (TCAM) , and/or static random-access memory (SRAM) .
  • Fig. 5 is a simplified block diagram of an apparatus 500 that may be used as either or both of the source device 12 and the destination device 14 from Fig. 1A according to an exemplary embodiment.
  • a processor 502 in the apparatus 500 can be a central processing unit.
  • the processor 502 can be any other type of device, or multiple devices, capable of manipulating or processing information now-existing or hereafter developed.
  • the disclosed implementations can be practiced with a single processor as shown, e.g., the processor 502, advantages in speed and efficiency can be achieved using more than one processor.
  • a memory 504 in the apparatus 500 can be a read only memory (ROM) device or a random access memory (RAM) device in an implementation. Any other suitable type of storage device can be used as the memory 504.
  • the memory 504 can include code and data 506 that is accessed by the processor 502 using a bus 512.
  • the memory 504 can further include an operating system 508 and application programs 510, the application programs 510 including at least one program that permits the processor 502 to perform the methods described herein.
  • the application programs 510 can include applications 1 through N, which further include a video coding application that performs the methods described herein.
  • the apparatus 500 can also include one or more output devices, such as a display 518.
  • the display 518 may be, in one example, a touch sensitive display that combines a display with a touch sensitive element that is operable to sense touch inputs.
  • the display 518 can be coupled to the processor 502 via the bus 512.
  • the bus 512 of the apparatus 500 can be composed of multiple buses.
  • a secondary storage (not shown) can be directly coupled to the other components of the apparatus 500 or can be accessed via a network and can comprise a single integrated unit such as a memory card or multiple units such as multiple memory cards.
  • the apparatus 500 can thus be implemented in a wide variety of configurations.
  • Motion vectors are usually at least partially determined at the encoder side and signaled to the decoder within the coded bitstream.
  • the motion vectors may also be refined at the decoder (and/or also at the encoder) starting from initial motion vectors indicated in the bitstream.
  • similarity between the patches or blocks of already decoded pixels pointed to by the initial motion vectors may be used to improve the accuracy of the initial motion vectors.
  • Such motion vector refinement provides an advantage of reducing the signaling overhead: the accuracy of the initial motion vector is improved in the same way at both the encoder and the decoder and thus, no additional signaling for the refinement is needed.
  • Initial motion vectors before refinement might not be the best motion vectors that result in the best prediction. Since the initial motion vectors are signaled in the bitstream, it might not be possible to represent the initial motion vector with very high accuracy (which would increase the bitrate) , therefore the motion vector refinement process is utilized to improve the initial motion vector.
  • Initial motion vectors might, for instance, be the motion vectors that are used in the prediction of a neighbor block of a current block. In this case, it is enough to signal an indication in the bitstream, indicating motion vectors of which neighbor block are used by the current block.
  • Such a prediction mechanism is very efficient in reducing the number of bits to represent the initial motion vectors.
  • the accuracy of the initial motion vectors might be low, since in general the motion vectors of two neighboring blocks are not expected to be identical.
  • the motion vector refinement may be performed at the decoder without assistance from the encoder.
  • the encoder in its decoder loop may employ the same refinement process to obtain corresponding refined motion vectors as would be available at the decoder.
  • the refinement for a current block (such as a sub-block of an image block (such as a coding block) ) that is being reconstructed in a current picture is performed by determining a template of reconstructed samples, determining a search space around the initial motion information for the current block (such as a sub-block of an image block (such as a coding block) ) and finding, in the search space, a reference picture portion best matching the template.
  • the best matching portion determines the refined motion vectors for the current block (such as a sub-block of an image block (such as a coding block) ) which is then used to obtain the inter-predicted samples for the current block (such as a sub-block of an image block (such as a coding block) ) , i.e. the current block being reconstructed.
  • Motion vector refinement is a part of the inter prediction unit 244 in Fig. 2, the inter prediction unit 344 in Fig. 3, and the inter prediction unit 744 in Fig. 7 .
  • an initial motion vector can be determined based on an indication in the bitstream.
  • an index may be signaled in the bitstream which indicates a position in a list of candidate motion vectors.
  • a motion vector predictor index and motion vector difference value can be signaled in the bitstream.
  • Motion vectors that are determined based on an indication in the bitstream are defined to be initial motion vectors.
  • refinement candidate motion vector (MV) pairs are determined for a sub-block of the image block (such as the current coding block) .
  • the refinement candidate motion vector pairs are determined for a sub-block of the image block (such as the current coding block) based on the initial motion vector pair (MV0, MV1) .
  • the candidate MV pairs may be determined by adding small motion vector differences to MV0 and MV1.
  • the candidate MV pairs might include the following:
  • (1, -1) denotes a vector that has a displacement of 1 integer pixel in the horizontal (or x) direction and a displacement of -1 integer pixel in the vertical (or y) direction.
  • Refinement candidate motion vector (MV) pairs form a search space of the motion vector refinement process.
  • two prediction blocks obtained using the respective first motion vector of list L0 and the second motion vector of list L1 are combined to a single prediction signal or block, which can provide a better adaptation to the original signal than uni-prediction, resulting in less residual information and possibly a more efficient compression.
  • the two prediction blocks obtained using the respective first motion vector and the second motion vector of a candidate MV pair are compared to each other based on a similarity metric for each of the refinement candidate MV pairs.
  • a candidate MV pair resulting in the highest similarity is usually selected as the refined motion vectors, denoted as MV0’ and MV1’, i.e. the refined motion vector in a first reference picture in list L0 and the refined motion vector in a second reference picture in list L1, respectively.
  • predictions are obtained corresponding to a list L0 motion vector and a list L1 motion vector of the candidate motion vector pair, which are then compared to each other based on a similarity metric.
  • the candidate motion vector pair that has the highest associated similarity is selected as refined the MV pair.
  • the output of the refinement process are refined MVs.
  • the refined MVs may be the same as the initial MVs or may be different from the initial MVs.
  • the candidate MV pair formed by the initial MVs is also among the candidate MV pairs. In other words, if the candidate MV pair that achieves the highest similarity is formed by the initial MVs, the refined MVs and the initial MVs are equal to each other.
  • the dis-similarity comparison measure may be SAD (Sum of absolute differences) , MRSAD (mean removed sum of absolute differences) , SSE (Sum of Squared Error) etc.
  • SAD Sum of absolute differences
  • MRSAD mean removed sum of absolute differences
  • SSE Sum of Squared Error
  • predSamplesL0 and predSamplesL1 are the prediction block samples obtained according to the candidate MV pair which is denoted by (CMV0, CMV1) .
  • the dis-similarity comparison measure may be obtained by evaluating only a subset of the samples in a prediction block, in order to reduce the number of computations.
  • An example is given below, where rows of samples are alternatively included in the SAD calculation (every second row is evaluated) .
  • JVET-M1001-v3 “Versatile Video Coding (Draft 4) ” of JVET (of ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11) which is publicly available under http: //phenix. it-sudparis. eu/jvet/.
  • the section “8.4.3 Decoder side motion vector refinement process” in the document exemplifies the motion vector refinement.
  • the motion vector refinement process may be performed independently on blocks of luma samples obtained by partitioning a coding block of samples that exceeds a certain pre-determined width and/or pre-determined height in luma samples into sub-blocks of samples that are smaller than or equal to the pre-determined width and the pre-determined height in luma.
  • the refined MV pair for each sub-block within a partitioned coding block may be different.
  • Fig. 9 shows a field of motion vectors for the sub-blocks of a partitioned coding block. Inter-prediction for both luma and chroma is then performed for each sub-block using the refined MV pair of that sub-block.
  • Each MV of the initial MV pair can have a fractional pixel precision.
  • the MV indicates a displacement between a current block of samples and a re-sampled reference region and this displacement can point to a fractional position in the horizontal and vertical directions from the integer grid of reconstructed reference samples.
  • a 2-dimensional interpolation of the integer grid of reconstructed reference sample values is performed to obtain the sample values at the fractional sample offset location.
  • the process of obtaining predicted samples from the reconstructed reference pictures using a candidate MV pair may be through one of the following methods:
  • the candidate MV pairs may have an arbitrary sub-pixel offset with respect to the initial MV pair, in some embodiments, for the sake of simplicity of search, the candidate MV pairs are chosen with integer pixel distance or integer displacement with respect to the initial MV pair.
  • Such candidate MV pairs with integer pixel distance with respect to the initial MV pair may also be used in a first stage of the motion vector refinement (MVR) process, the so-called integer-distance refinement stage of the MVR.
  • the predicted samples across all the candidate MV pairs can be obtained by performing a prediction for a block of samples around the initial MV pair to cover all the refinement positions around the initial MV pair.
  • the dis-similarity cost value at all the candidate MV pairs at an integer distance (integer displacement) from the initial MV pair may be evaluated.
  • additional candidate MV pairs at sub-pixel distance offsets from the best cost value position may be added. This second stage may be performed as a fractional-distance refinement stage of the MVR process. Predicted samples may be obtained for each of these positions using one of the methods described above and the dis-similarity costs are evaluated and compared to each other to obtain the position with the lowest dis-similarity cost.
  • the integer-distance cost values evaluated are stored and a parametric error surface is fitted in the vicinity of the best integer-distance position.
  • the minimum of this error surface is then analytically computed and used as the position with the minimum dis-similarity.
  • the dis-similarity cost value is said to be derived from the computed integer-distance cost values.
  • the application of motion vector refinement for a given coding block of samples may be conditioned on certain coding properties of the coding block of samples.
  • Some examples of such coding properties may include:
  • the initial dis-similarity between the two predicted blocks obtained using the initial MV pair is less than a pre-determined per-sample threshold.
  • BPOF Bi-predictive Optical flow refinement
  • Bi-predictive optical flow (BPOF) or Bi-Directional Optical Flow (BDOF) refinement is a process of improving the accuracy of bi-prediction of a block, without explicit additional signaling in the bitstream other than the signaling for bi-prediction. It is a part of the inter prediction unit 244 in Fig. 2 and 344 in Fig. 3.
  • bi-prediction 2 inter-predictions are obtained according to two motion vectors, then the predictions are combined by application of weighted averaging.
  • the combined prediction may result in a reduced residual energy as the quantization noise in the two reference patches or blocks get canceled out, thereby providing a better coding efficiency than uni-prediction.
  • the weighted combination in bi-prediction may be performed according to the following equation:
  • Bi-prediction Prediction1 *W1 + Prediction2 *W2 + K
  • W1 and W2 are weighting factors that may be signaled in the bitstream or may be predefined at the encoder side and/or at the decoder side.
  • K is an additive factor which may also be signaled in the bitstream or be predefined at the encoder side and/or at the decoder side.
  • bi-prediction may be obtained using
  • Bi-prediction (Prediction1 + Prediction2) /2
  • W1 and W2 are set to 1/2 and K is set to 0.
  • optical flow refinement is to improve the accuracy of the bi-prediction.
  • Optical flow is the pattern of apparent motion of image objects between two consecutive frames.
  • Optical flow is caused by the movement of the object and/or the camera.
  • the optical flow refinement process improves the accuracy of the bi-prediction by application of an optical flow equation (solving of the optical flow equation) .
  • a pixel I (x, y, t) is located in a first frame (x and y corresponding to spatial coordinates, t corresponding to time dimension) .
  • the object represented by the pixel moves by a distance (dx, dy) in the next frame taken after dt time.
  • the optical flow equation is given by:
  • I (x, y, t) I (x+ dx , y+ dy , t+dt)
  • I (x, y, t) specifies the intensity (sample value) of a pixel at the coordinates of (x, y, t) .
  • optical flow equation may also be written as:
  • the optical flow refinement utilizes the principle above in order to improve the quality of bi-prediction.
  • optical flow refinement typically includes the steps of:
  • I (0) corresponds to a sample value in the first prediction
  • I (1) is the sample value in the second prediction
  • v x and v y are the displacement velocities calculated in x- and y-directions
  • ⁇ 1 and ⁇ 0 denote the temporal distances from the current picture in display order to the respective reference pictures, where the first predition and the second prediction are obtained.
  • pred BIO specifies the modified prediction which is the output of the optical flow refinement process.
  • Sample gradients may be obtained according to the following formulas:
  • the displacement in order to simplify the complexity of estimating the displacement for each pixel, the displacement is estimated for a group of pixels.
  • the displacements are estimated using sample values of a block of 8x8 luma samples with the 4x4 block of samples at its center.
  • the input of the optical flow refinement process are the prediction samples from two reference pictures and the output of the optical flow refinement is the combined prediction (predBIO) which is calculated according to optical flow equation.
  • optical flow refinement bi-predictive optical flow refinement and bidirectional optical flow refinement may be used interchangeably in the disclosure.
  • a deblocking filter is applied to the reconstructed samples adjacent to a sub-block or transform unit (TU) boundary except for the case when the boundary is also a picture boundary, or when deblocking is disabled across slice boundaries or tile boundaries (which is an option that can be signaled by the encoder) .
  • TU sub-block or transform unit
  • both sub-block and TU boundaries should be considered since sub-block boundaries are not always aligned with TU boundaries in some cases of inter-coded coding blocks (CBs) .
  • deblocking is applied to the edges which are aligned to 8x8 sample grid.
  • deblocking is applied to all sub-block edges within a CU which overlap with a 4x4 sample grid.
  • the filter strength (such as boundary strength) of the deblocking filtering is controlled by one or more syntax elements wherein the filter strength (such as boundary strength) can take a value in the range of 0 to 2.
  • a filter strength of 2 may be assigned when one of the blocks is intra-coded. Otherwise, a filter strength of 1 may be assigned if any one of the following conditions is satisfied:
  • ⁇ P or Q has at least one non-zero transform coefficient.
  • a filter strength of 0 may be assigned, which means that the deblocking process is not applied.
  • two thresholds, tC and ⁇ may be determined from pre-defined tables.
  • tC and ⁇ may be determined from pre-defined tables.
  • no filtering, strong filtering, and weak filtering may be chosen according to experimental rules based on ⁇ . Note that this decision is shared across four luma rows or columns using the first and the last rows or columns to reduce the computational complexity.
  • no filtering and normal filtering for chroma samples. Normal filtering is applied only when the filter strength is greater than one. The actual filtering process for the samples is performed based on both values of tC and ⁇ .
  • the processing order of the deblocking filter is defined as performing horizontal filtering for vertical edges 605 (blocks 601 and 602 of Fig. 6A) for the entire picture first, followed by vertical filtering for horizontal edges 606 (blocks 603 and 604 of Fig. 6B) .
  • This specific order enables either multiple horizontal filtering or vertical filtering processes to be applied in parallel threads, and can still be implemented on a CTB by CTB basis with only small processing latency.
  • the deblocking related to the decoder-side motion vector refinement is performed on internal edges without using refined MVs under one or more specific conditions.
  • a method for deblocking a sub-block edge between a first sub-block and a second sub-block of a current block may be implemented in a video encoding device or a video decoding device with the following steps shown in Fig. 12 and may in particular, be performed by the loop filter shown in Fig. 2 and Fig. 3:
  • Step 1210 in the case that motion vector refinement is enabled and/or applied for the current block, determining, according to at least one rule, at least one filtering related parameter associated with the sub-block edge;
  • Step 1220 performing deblocking filtering on the sub-block edge based on the at least one filtering related parameter, wherein the at least one rule is independent of refined motion information.
  • maximum filter lengths for the respective sub-blocks of the current image block may be assigned or determined.
  • the maximum filter length may be a first value (e.g. 1) for a first sub-block of the current image block, and the maximum filter length may be a second value (e.g. 1) for a second sub-block of the current image block.
  • the maximum filter length may be associated with a sub-block and applied to respective one or more sub-block edges of this sub-block.
  • maximum filter lengths for deblocking the respective sub-blocks of a current image block for which MVR (e.g. DMVR) is enabled or for which MVR (e.g. DMVR) is applied may be determined (such as based on a rule) .
  • the rule may be defined in different ways, for example, the quantization parameter (QP) of the current image block (such as a current coding block) may be used to determine the maximum filter lengths for the respective sub-blocks of the current image block which is enabled for MVR.
  • a filter strength (such as boundary strength) for deblocking the internal edges of a current image block for which MVR (e.g. DMVR) is enabled or applied, may be determined based on a rule (without deriving based on refined motion information, such as refined MVs of sub-blocks of the image block) .
  • the rule may be defined in different ways.
  • the quantization parameter (QP) of the current block may be used to determine the filter strength (such as boundary strength) for deblocking the internal edges of a current block which is enabled for MVR.
  • the filter (boundary) strength for internal edges for DMVR is fixed at a chosen value or a chosen value range (wherein a preferred value for this chosen value may be 1) .
  • the maximum filter length may be chosen accordingly, or maintained at a default value as per the coding process.
  • the following table presents a rule-based framework for some embodiments.
  • the present disclosure includes but is not limited to the example conditions mentioned in the table.
  • the table identifies if-then associations. Accordingly, the rule-antecedent denotes the “if” condition under which the rule triggers, and the rule-consequent denotes the action taken under the “then” clause of the if-then association rule.
  • SPS is the Sequence Parameter Set
  • PPS is the Picture Parameter Set.
  • ⁇ Filter length can be chosen to be any chosen value, say 1 or 2 or 3
  • the internal edges refer to internal edges between sub-blocks, or a sub-block edge.
  • a sub-block edge is an edge shared between two sub-blocks whose motion vectors can be different
  • a block edge i.e. a coding unit (CU) edge or a coding block edge or CU boundary
  • CU coding unit
  • CU boundary coding block edge
  • the maximum filter length is related to the maximum number of output samples which are modified on one side of the edge after filtering, i.e. the samples which are arranged in a line perpendicular to a given block edge and adjacent to the edge.
  • a deblocking filter uses a number of maximum filtering samples as input and also modifies a number of maximum samples as filter output.
  • the filter length may refer to the number of inputs or outputs. In the previous example, it refers to the number of outputs.
  • the boundary strength is derived based on one or more syntax elements like block type, coded (intra coded or inter coded) or not coded and motion information.
  • Sub-block internal edges which are not transform edges of inter coded blocks use only the motion vectors and the reference (picture) indices to determine the boundary strength.
  • Non-MVR blocks (blocks for which DMVR is disabled) have the motion information available soon after MVD parsing and MVP candidate index is parsed (as shown in Fig. 7) . This enables the hardware or software design to compute the boundary strength before motion compensation (770) .
  • MVR blocks (blocks for which MVR is enabled) have the final refined motion information available only after the motion vector refinement (772) .
  • This disclosure provides a method to use a boundary strength and/or maximum filter lengths (such as a fixed boundary strength and/or fixed maximum filter lengths) for MVR internal edges (internal edges of a block for which MVR is enabled) under the above-mentioned conditions (i.e. current block QP (QP of a current block) greater than a particular value or a pre-set value) .
  • current block QP QP of a current block
  • initial MVs may be used to derive the BS, but MVs are not used to derive the maximum filter length.
  • the BS is derived based on motion information while the maximum filter length is not derived based on motion information.
  • the BS needs to be calculated based on initial motion vectors for sub-block edges.
  • a deblocking filter uses as input and output samples the samples which are arranged perpendicular and adjacent to a given block edge. Moreover, the deblocking filter may use a number of samples (not more than the maximum filtering length) as input and also modify a number of samples (not more than the maximum filtering length) as filter output. The decision on the number of samples used as input and on the number of modified samples follows predefined rules and is known as a deblocking decision. For a filter length of 1, one sample from each side of the edge may be modified, but not more than that.
  • dmvr_flag [x0] [y0] specifies whether the decoder side motion vector refinement is applied for the current unit.
  • the array indices x0, y0 specify the location (x0, y0) of the top-left luma sample of the considered coding block relative to the top-left luma sample of the picture.
  • dmvr_flag [x0] [y0] is inferred as 1, if the following conditions are true:
  • sps_dmvr_enabled_flag is equal to 1 and slice_disable_bdof_dmvr_flag is equal to 0
  • DiffPicOrderCnt (currPic, RefPicList [0] [refIdxL0] ) is equal to DiffPicOrderCnt (RefPicList [1] [refIdxL1] , currPic)
  • the pic_width_in_luma_samples and pic_height_in_luma_samples of the reference picture refPicLX associated with the refIdxLX are equal to the pic_width_in_luma_samples and pic_height_in_luma_samples of the current picture, respectively.
  • nCbW specifying the width of the current coding block
  • nCbH specifying the height of the current coding block
  • variable edgeType specifying whether a vertical (EDGE_VER) or a horizontal (EDGE_HOR) edge is filtered.
  • the number of coding sub-blocks in horizontal direction numSbX and in vertical direction numSbY are derived as follows:
  • inter_affine_flag [xCb] [yCb] is equal to 1 or merge_subblock_flag [xCb] [yCb] is equal to 1 or dmvr_Flag [xCb] [yCb] is equal to 1
  • numSbX and numSbY are set equal to NumSbX [xCb] [yCb] and NumSbY [xCb] [yCb] , respectively.
  • numSbX and numSbY are both set equal to 1.
  • edgeType Depending on the value of edgeType the following applies:
  • edgeType is equal to EDGE_VER, the following applies:
  • the variable sbW is set equal to Max (8, nCbW /numSbX) .
  • edgeTbFlags is set equal to edgeFlags.
  • the horizontal position x inside the current coding block is set equal to xEdge *sbW.
  • edgeFlags [x] [y] The value of edgeFlags [x] [y] is derived as follows:
  • pps_num_ver_virtual_boundaries -1 the following applies:
  • maxFilterLengthQs [x] [y] Min (5, maxFilterLengthQs [x] [y] )
  • maxFilterLengthPs [x] [y] Min (5, maxFilterLengthPs [x] [y] )
  • edgeTbFlags [x] [y] is equal to 1, the following applies:
  • maxFilterLengthPs [x] [y] Min (5, maxFilterLengthPs [x] [y] )
  • maxFilterLengthQs [x] [y] Min (5, maxFilterLengthQs [x] [y] )
  • edgeTbFlags [x -4] [y] is equal to 1,
  • edgeTbFlags [x + 4] [y] is equal to 1,
  • edgeTbFlags [x -sbW] [y] is equal to 1,
  • edgeTbFlags [x + sbW] [y] is equal to 1,
  • edgeType is equal to EDGE_HOR, the following applies:
  • the variable sbH is set equal to Max (8, nCbH /numSbY) .
  • edgeTbFlags is set equal to edgeFlags.
  • the vertical position y inside the current coding block is set equal to yEdge *sbH.
  • edgeFlags [x] [y] The value of edgeFlags [x] [y] is derived as follows:
  • pps_num_hor_virtual_boundaries -1 the following applies:
  • maxFilterLengthQs [x] [y] Min (5, maxFilterLengthQs [x] [y] )
  • maxFilterLengthPs [x] [y] Min (5, maxFilterLengthPs [x] [y] )
  • edgeTbFlags [x] [y] is equal to 1, the following applies:
  • maxFilterLengthPs [x] [y] Min (5, maxFilterLengthPs [x] [y] )
  • maxFilterLengthQs [x] [y] Min (5, maxFilterLengthQs [x] [y] )
  • edgeTbFlags [x] [y -4] is equal to 1,
  • edgeTbFlags [x] [y + 4] is equal to 1,
  • edgeTbFlags [x] [y -sbH] is equal to 1,
  • edgeTbFlags [x] [y + sbH] is equal to 1,
  • nCbW specifying the width of the current coding block
  • nCbH specifying the height of the current coding block
  • variable edgeType specifying whether a vertical (EDGE_VER) or a horizontal (EDGE_HOR) edge is filtered
  • variable cIdx specifying the colour component of the current coding block
  • Output of this process is a two-dimensional (nCbW) x (nCbH) array bS specifying the boundary filtering strength.
  • variable gridSize is set as follows:
  • edgeType is equal to EDGE_VER
  • xN is set equal to Max (0, (nCbW /gridSize) -1)
  • edgeType is equal to EDGE_HOR
  • edgeType is equal to EDGE_VER
  • p 0 is set equal to recPicture [xCb + xD i -1] [yCb + yD j ]
  • q 0 is set equal to recPicture [xCb + xD i ] [yCb + yD j ] .
  • edgeType is equal to EDGE_HOR
  • p 0 is set equal to recPicture [xCb + xD i ] [yCb + yD j -1]
  • q 0 is set equal to recPicture [xCb + xD i ] [yCb + yD j ] .
  • bS [xD i ] [yD j ] is set equal to 1.
  • cIdx is greater than 0, and the sample p 0 or q 0 is in a transform unit with tu_joint_cbcr_residual_flag equal to 1, bS [xD i ] [yD j ] is set equal to 1.
  • bS [xD i ] [yD j ] is set equal to 1.
  • cIdx is equal to 0, it means that a first sub-block (such as the sample p0) and a second sub-block (such as the sample q0) may be luma blocks or luma components.
  • Fig. 8 is a block diagram illustrating an exemplary deblocking filter apparatus 800 according to the techniques described in this disclosure (further details will be described below, e.g., based on Figs. 7 or 8) .
  • the deblocking filter apparatus 800 may be configured to perform deblocking techniques in accordance with various examples described in the present application.
  • loop filter 220 from Fig. 2 and loop filter 320 from Fig. 3 may include components substantially similar to those of deblocking filter apparatus 800.
  • Other video coding devices such as video encoders, video decoders, video encoder/decoders (CODECs) , and the like may also include components substantially similar to deblocking filter apparatus 800.
  • Deblocking filter apparatus 800 may be implemented in hardware, software, or firmware, or any combination thereof. When implemented in software or firmware, corresponding hardware (such as one or more processors or processing units and memory for storing instructions for the software or firmware) may also be provided.
  • deblocking filter apparatus 800 includes deblocking determination unit 804, support definitions 802 stored in memory, deblocking filtering unit 806, deblocking filter parameters 808 stored in memory, edge locating unit 803, and edge locations data structure 805. Any or all of the components of deblocking filter 800 may be functionally integrated. The components of deblocking filter 800 are illustrated separately only for purposes of illustration. In general, deblocking filter 800 receives data for decoded blocks, e.g., from a summation component 214, 314 that combines prediction data with residual data for the blocks. The data may further include an indication of how the blocks were predicted.
  • deblocking filter apparatus 800 is configured to receive data including a decoded video block associated with a CTB (or a largest coding unit (LCU) ) and a CU quadtree for the CTB, where the CU quadtree describes how the CTB is partitioned into CUs and prediction modes for PUs and TUs of leaf-node CUs.
  • a CTB or a largest coding unit (LCU)
  • LCU quadtree describes how the CTB is partitioned into CUs and prediction modes for PUs and TUs of leaf-node CUs.
  • Deblocking filter apparatus 800 may maintain edge locations data structure 805 in a memory of deblocking filter apparatus 800, or in an external memory provided by a corresponding video coding device.
  • edge locating unit 803 may receive a quadtree corresponding to a CTB that indicates how the CTB is partitioned into CUs. Edge locating unit 803 may then analyze the CU quadtree to determine edges between decoded video blocks associated with TUs and PUs of CUs in the CTB that are candidates for deblocking.
  • Edge locations data structure 805 may comprise an array having a horizontal dimension, a vertical dimension, and a dimension representative of horizontal edges and vertical edges.
  • edges between video blocks may occur between two video blocks associated with smallest-sized CUs of the CTB, or TUs and PUs of the CUs.
  • the array may comprise a size of [N/M] ⁇ [N/M] ⁇ 2, where “2” represents the two possible directions of edges between CUs (horizontal and vertical) .
  • the array may comprise [8] ⁇ [8] ⁇ [2] entries.
  • Each entry may generally correspond to a possible edge between two video blocks. Edges might not in fact exist at each of the positions within the LCU corresponding to each of the entries of edge locations data structure 805. Accordingly, values of the data structure may be initialized to false.
  • edge locating unit 803 may analyze the CU quadtree to determine locations of edges between two video blocks associated with TUs and PUs of CUs of the CTB and set corresponding values in edge locations data structure 805 to true.
  • the entries of the array may describe whether a corresponding edge exists in the CTB as a candidate for deblocking. That is, when edge locating unit 803 determines that an edge between two neighboring video blocks associated with TUs and PUs of CUs of the CTB exists, edge locating unit 803 may set a value of the corresponding entry in edge locations data structure 805 to indicate that the edge exists (e.g., to a value of “true” ) .
  • Deblocking determination unit 804 generally determines whether, for two neighboring blocks, an edge between the two blocks should be deblocked.
  • Deblocking determination unit 804 may determine locations of edges using edge locations data structure 805. When a value of edge locations data structure 805 has a Boolean value, deblocking determination unit 804 may determine that a “true” value indicates the presence of an edge, and a “false” value indicates that no edge is present, in some examples.
  • deblocking determination unit 804 is configured with one or more deblocking determination functions.
  • the functions may include a plurality of coefficients applied to sequences of pixels across the edge between the blocks.
  • the functions may be applied to a sequence of pixels that is perpendicular to the edge, where MA (such as 3, 4 or 5) pixels are in one of the two blocks and MB (such as 7) pixels are in the other of the two blocks.
  • Support definitions 802 define support for the functions.
  • the “support” corresponds to the pixels to which the functions are applied.
  • the “support” corresponds to the number of taps of a filter or the filter length.
  • Deblocking determination unit 804 may be configured to apply one or more deblocking determination functions to one or more sets of support, as defined by support definitions 802, to determine whether a particular edge between two blocks of video data should be deblocked.
  • the dashed line originating from deblocking determination unit 804 represents data for blocks being output without being filtered.
  • deblocking filter apparatus 800 may output the data for the blocks without altering the data. That is, the data may bypass deblocking filtering unit 806.
  • deblocking determination unit 804 may cause deblocking filtering unit 806 to filter values for pixels near the edge in order to deblock the edge.
  • Deblocking filtering unit 806 retrieves definitions of deblocking filters from deblocking filter parameters 808 for edges to be deblocked, as indicated by deblocking determination unit 804.
  • filtering of an edge uses values of pixels from the neighborhood of a current edge to be deblocked. Therefore, both deblocking determination functions and deblocking filters may have a certain support region on both sides of an edge.
  • deblocking filtering unit 806 may smooth the values of the pixels such that high frequency transitions near the edge are dampened. In this manner, application of deblocking filters to pixels near an edge may reduce blockiness artifacts near the edge.
  • Fig. 10 is a block diagram showing a content supply system 3100 for realizing content distribution service.
  • This content supply system 3100 includes capture device 3102, terminal device 3106, and optionally includes display 3126.
  • the capture device 3102 communicates with the terminal device 3106 over communication link 3104.
  • the communication link may include the communication channel 13 described above.
  • the communication link 3104 includes but not limited to WIFI, Ethernet, Cable, wireless (3G/4G/5G) , USB, or any kind of combination thereof, or the like.
  • the capture device 3102 generates data, and may encode the data by the encoding method as shown in the above embodiments.
  • the capture device 3102 may distribute the data to a streaming server (not shown in the Figures) , and the server encodes the data and transmits the encoded data to the terminal device 3106.
  • the capture device 3102 includes but not limited to camera, smart phone or Pad, computer or laptop, video conference system, PDA, vehicle mounted device, or a combination of any of them, or the like.
  • the capture device 3102 may include the source device 12 as described above.
  • the video encoder 20 included in the capture device 3102 may actually perform video encoding processing.
  • an audio encoder included in the capture device 3102 may actually perform audio encoding processing.
  • the capture device 3102 distributes the encoded video and audio data by multiplexing them together.
  • the encoded audio data and the encoded video data are not multiplexed.
  • Capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.
  • the terminal device 310 receives and reproduces the encoded data.
  • the terminal device 3106 could be a device with data receiving and recovering capability, such as smart phone or Pad 3108, computer or laptop 3110, network video recorder (NVR) /digital video recorder (DVR) 3112, TV 3114, set top box (STB) 3116, video conference system 3118, video surveillance system 3120, personal digital assistant (PDA) 3122, vehicle mounted device 3124, or a combination of any of them, or the like capable of decoding the above-mentioned encoded data.
  • the terminal device 3106 may include the destination device 14 as described above.
  • the encoded data includes video
  • the video decoder 30 included in the terminal device is prioritized to perform video decoding.
  • an audio decoder included in the terminal device is prioritized to perform audio decoding processing.
  • the terminal device can feed the decoded data to its display.
  • NVR network video recorder
  • DVR digital video recorder
  • TV 3114 TV 3114
  • PDA personal digital assistant
  • the terminal device can feed the decoded data to its display.
  • STB 3116, video conference system 3118, or video surveillance system 3120 an external display 3126 is contacted therein to receive and show the decoded data.
  • the picture encoding device or the picture decoding device can be used.
  • Fig. 11 is a diagram showing a structure of an example of the terminal device 3106.
  • the protocol proceeding unit 3202 analyzes the transmission protocol of the stream.
  • the protocol includes but not limited to Real Time Streaming Protocol (RTSP) , Hyper Text Transfer Protocol (HTTP) , HTTP Live streaming protocol (HLS) , MPEG-DASH, Real-time Transport protocol (RTP) , Real Time Messaging Protocol (RTMP) , or any kind of combination thereof, or the like.
  • RTSP Real Time Streaming Protocol
  • HTTP Hyper Text Transfer Protocol
  • HLS HTTP Live streaming protocol
  • MPEG-DASH Real-time Transport protocol
  • RTP Real-time Transport protocol
  • RTMP Real Time Messaging Protocol
  • stream file is generated.
  • the file is outputted to a demultiplexing unit 3204.
  • the demultiplexing unit 3204 can separate the multiplexed data into the encoded audio data and the encoded video data. As described above, for some practical scenarios, for example in the video conference system, the encoded audio data and the encoded video data are not multiplexed. In this situation, the encoded data is transmitted to video decoder 3206 and audio decoder 3208 without through the demultiplexing unit 3204.
  • video elementary stream (ES) ES
  • audio ES and optionally subtitle are generated.
  • the video decoder 3206 which includes the video decoder 30 as explained in the above mentioned embodiments, decodes the video ES by the decoding method as shown in the above-mentioned embodiments to generate video frame, and feeds this data to the synchronous unit 3212.
  • the audio decoder 3208 decodes the audio ES to generate audio frame, and feeds this data to the synchronous unit 3212.
  • the video frame may store in a buffer (not shown in FIG. Y) before feeding it to the synchronous unit 3212.
  • the audio frame may store in a buffer (not shown in FIG. Y) before feeding it to the synchronous unit 3212.
  • the synchronous unit 3212 synchronizes the video frame and the audio frame, and supplies the video/audio to a video/audio display 3214.
  • the synchronous unit 3212 synchronizes the presentation of the video and audio information.
  • Information may code in the syntax using time stamps concerning the presentation of coded audio and visual data and time stamps concerning the delivery of the data stream itself.
  • the subtitle decoder 3210 decodes the subtitle, and synchronizes it with the video frame and the audio frame, and supplies the video/audio/subtitle to a video/audio/subtitle display 3216.
  • the present invention is not limited to the above-mentioned system, and either the picture encoding device or the picture decoding device in the above-mentioned embodiments can be incorporated into other system, for example, a car system.
  • Fig. 13 shows a block diagram illustrating an example of an encoder/decoder for coding a video sequence, in particular, for deblocking filtering on a sub-block edge between a first sub-block and a second sub-block of a current block according to embodiments of the disclosure.
  • the decoder 30/70 and the encoder 20 each comprise a determining unit 1310 configured to, in the case that motion vector refinement is enabled and/or applied for a current block, determine, according to at least one rule, at least one filtering related parameter associated with a sub-block edge between a first sub-block and a second sub-block of the current block, and a deblocking unit 1320 configured to perform deblocking filtering on the sub-block edge based on the at least one filtering related parameter, wherein the at least one rule is independent of refined motion information.
  • the determining unit 1310 and the deblocking unit 1320 may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted over communication media as one or more instructions or code and executed by a hardware-based processing unit. Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs) , general purpose microprocessors, application specific integrated circuits (ASICs) , field programmable logic arrays (FPGAs) , or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor, ” as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block (such as a current coding unit) , in an image encoding and/or an image decoding, comprising:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) , assigning or setting, values of one or more filtering related parameters (such as respective maximum filter length parameters) associated with the first sub-block and the second sub-block which is adjacent to the sub-block internal edge, as first values (or assigning or setting, values of one or more filtering related parameters (such as a boundary strength parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block, as first values) ; and
  • maxFilterLengthPs [x] [y] a second value (such as 1) ,
  • maxFilterLengthQs [x] [y] a third value (such as 1) ,
  • maxFilterLengthPs [x] [y] represents a max maximum filter length for the first sub-block and maxFilterLengthQs [x] [y] represent a max maximum filter length for the second sub-block
  • the sample at (x, y) represent horizontal position x and vertical position y of a sample (such as the top-left luma sample) of a respective sub-block relative to the top-left luma sample of the current block.
  • bS [] [] is set equal to a fourth value (such as 1) , wherein bS [] [] represents a boundary filtering strength used for deblocking the sub-block internal edge between the first sub-block and the second sub-block.
  • a derived threshold QP may be a sum of a fifth value (such as 45) and a threshold QP delta value (such as, 45 + slice_dmvr_qp_th_minus_45) or a derived threshold QP may be based on a sum of a fifth value (such as 45) and a threshold QP delta value (such as, 45 + slice_dmvr_qp_th_minus_45) .
  • a syntax element for indicating the threshold QP delta value may be obtained from any one of a sequence parameter set (SPS) level of a bitstream, a picture parameter set (PPS) level of the bitstream, a slice header, coding tree unit (CTU) syntax, or coding unit (CU) syntax.
  • SPS sequence parameter set
  • PPS picture parameter set
  • CTU coding tree unit
  • CU coding unit
  • the current block may be an inter-coded block, and the sub-block edge may not be a transform unit (TU) boundary (such as sub-block TU boundary or internal TU boundary) of the current block.
  • TU transform unit
  • the first sub-block and the second sub-block may be luma sub-blocks.
  • the second sub-block may be adjacent to the first sub-block.
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, in an image encoding and/or an image decoding, comprising:
  • DMVR motion vector refinement
  • DMVR decoder side motion vector refinement
  • deriving at least based on one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such as, boundary strength parameter (BS) ) associated with the sub-block edge between the first sub-block and the second sub-block;
  • one or more refined Motion Vectors such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs)
  • filtering related parameters such as, boundary strength parameter (BS)
  • DMVR motion vector refinement
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as, boundary strength parameter
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, in an image encoding and/or an image decoding, comprising:
  • DMVR motion vector refinement
  • deriving without using one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such a boundary strength parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block;
  • one or more refined Motion Vectors such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs)
  • filtering related parameters such as a boundary strength parameter
  • DMVR motion vector refinement
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pair of initial MVs)
  • filtering related parameters such as, a boundary strength parameter
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, in an image encoding and/or an image decoding, comprising:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • deriving without using one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such a boundary strength parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block under one or more first conditions;
  • one or more refined Motion Vectors such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs)
  • motion vector refinement is disabled for the current block (or decoder side motion vector refinement (DMVR) is not applied for the current block) (such as dmvr_Flag is equal to false or 0) ,
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as, a boundary strength parameter
  • the initial motion information of the current image block may comprise a first initial motion vector, a first reference index, a second initial motion vector and a second reference index, wherein the first reference index indicates a first reference picture, and the second reference index indicates a second reference picture.
  • the method may be applied for an encoder, and an index for indicating initial motion information may be included in an encoded bitstream.
  • the method may be applied for a decoder, and an index for indicating initial motion information may be parsed from a bitstream.
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block (such as a current coding unit) , in an image encoding and/or an image decoding, comprising:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • deriving without using one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such as, boundary strength parameter and/or filter length parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block (or associated with the first sub-block and the second sub-block which is near to the sub-block internal edge) under one or more first conditions; and performing deblocking filtering at values of samples near the sub-block internal edge (such as perpendicular to and adjacent to the sub-block internal edge) between the first sub-block and the second sub-block based on the values of the filtering related parameters.
  • filtering related parameters such as, boundary strength parameter and/or filter length parameter
  • At least one of the one or more first conditions may be associated with a quantization parameter (QP) of the current block, or at least one of the one or more first conditions may be represented in terms of the quantization parameter (QP) of the current block.
  • QP quantization parameter
  • the one or more first conditions may comprise (or the first condition may be) : the quantization parameter (QP) of the current block is larger than a value (such as a pre-set value) ; or
  • the quantization parameter (QP) of the current block is in a value range (such as a pre-set value range) .
  • the current block may be an inter-coded block, wherein the step of deriving, without using one or more refined Motion Vectors, values of one or more filtering related parameters (such a boundary strength parameter and/or filter length parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block under one or more first conditions, comprises:
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • the threshold QP may be signaled at any one of a sequence parameter set (SPS) level, a picture parameter set (PPS) level, a slice header, coding tree unit (CTU) syntax, or coding unit (CU) syntax; or
  • a threshold QP delta value (such as, pps_dmvr_qp_th_minus_45;
  • slice_dmvr_qp_th_minus_45 which is used for deriving the derived threshold QP, may be signaled at any one of a sequence parameter set (SPS) level, a picture parameter set (PPS) level, a slice header, coding tree unit (CTU) syntax, or coding unit (CU) syntax.
  • SPS sequence parameter set
  • PPS picture parameter set
  • CTU coding tree unit
  • CU coding unit
  • the current block may be an inter-coded block, and the sub-block internal edge may not be a transform unit (TU) boundary (such as sub-block TU boundary or internal TU boundary) of the current block.
  • TU transform unit
  • the first sub-block and the second sub-block may be luma sub-blocks.
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, in an image encoding and/or an image decoding, comprising:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as a boundary strength parameter associated with the sub-block internal edge between the first sub-block and the second sub-block under one or more second conditions (such as, when one or more first conditions are not met, e.g. if one or more QP-defined-conditions are not met) ;
  • At least one of the one or more first or second conditions may be associated with a quantization parameter (QP) of the current block, or at least one of the one or more first or second conditions may be represented in terms of the quantization parameter (QP) of the current block.
  • QP quantization parameter
  • the one or more second conditions may comprise (or the second condition may comprise) :
  • the quantization parameter (QP) of the current block is smaller than or equal to a pre-set value
  • the quantization parameter (QP) of the current block is not in a pre-set range value.
  • the current block may be an inter-coded block, and under the one or more second conditions, assigning the filter strength of a first BS value (such as 1) if any of the following conditions is satisfied:
  • ⁇ a first sub-block or a second sub-block has at least one non-zero transform coefficient
  • ⁇ the difference between each initial motion vector component of the first sub-block and the second sub-block is equal to or greater than one integer sample.
  • the current block may be an inter-coded block, and the sub-block internal edge may not be a transform unit (TU) boundary (such as sub-block TU boundary or internal TU boundary) of the current block.
  • TU transform unit
  • a deblocking method for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, in an image encoding and/or an image decoding, comprising:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • the rule may be defined according to a quantization parameter (QP) of the current block, or
  • the rule may be represented in terms of the quantization parameter (QP) of the current block, or
  • the rule may be associated with the quantization parameter (QP) of the current block.
  • the rule may be defined as follows:
  • a value of the boundary strength parameter is set to a first BS value, and/or a value of a maximum filter length parameter is set to a first length value;
  • a value of the boundary strength parameter is set to a first BS value, and/or a value of a maximum filter length parameter is set to a first length value.
  • the step of deriving, based on a rule, values of one or more filtering related parameters associated with the sub-block internal edge between the first sub-block and the second sub-block may comprise:
  • QP quantization parameter
  • QP quantization parameter
  • the step of deriving, based on a rule, values of one or more filtering related parameters associated with the sub-block internal edge between the first sub-block and the second sub-block may comprise:
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • QP quantization parameter
  • the current block may be an inter-coded block, and the sub-block internal edge may not be a transform unit (TU) boundary (such as sub-block TU boundary or internal TU boundary) of the current block.
  • TU transform unit
  • the step of performing deblocking filtering at values of samples near the sub-block internal edge between the first sub-block and the second sub-block based on the values of the filtering related parameters may comprise:
  • sub-block internal edge is a horizontal block edge (606) , the direction along the height of the first sub-block being perpendicular to the horizontal block edge (606) , and the direction along the height of the second sub-block being perpendicular to the horizontal block edge (606) ; or
  • the sub-block internal edge is a vertical block edge (605) , the direction along the width of the first sub-block being perpendicular to the vertical block edge (605) , and the direction along the width of the second sub-block being perpendicular to the vertical block edge (605) .
  • the first sub-block may be left to the second sub-block.
  • the first sub-block and the second sub-block may not be transform blocks.
  • the method may be applied for an encoder, wherein an index for indicating initial motion information is included in an encoded bitstream.
  • a deblocking filter apparatus for use in an image encoder and/or an image decoder, for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, is provided,
  • deblocking filter apparatus is configured to:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • deriving at least based on one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such a boundary strength parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block (or associated with the first sub-block and the second sub-block which are adjacent to the sub-block edge) ;
  • refined Motion Vectors such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs)
  • filtering related parameters such as a boundary strength parameter associated with the sub-block internal edge between the first sub-block and the second sub-block (or associated with the first sub-block and the second sub-block which are adjacent to the sub-block edge) ;
  • DMVR motion vector refinement
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as, a boundary strength parameter
  • a deblocking filter apparatus for use in an image encoder and/or an image decoder, for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, is provided,
  • deblocking filter apparatus is configured to:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • deriving without using one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such a boundary strength parameter) associated with the sub-block edge between the first sub-block and the second sub-block;
  • one or more refined Motion Vectors such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs)
  • DMVR motion vector refinement
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as a boundary strength parameter
  • a deblocking filter apparatus for use in an image encoder and/or an image decoder, for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, is provided,
  • deblocking filter apparatus is configured to:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • deriving without using one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such a boundary strength parameter) associated with the sub-block edge between the first sub-block and the second sub-block under one or more first conditions;
  • one or more refined Motion Vectors such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs)
  • DMVR motion vector refinement
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as a boundary strength parameter
  • a deblocking filter apparatus for use in an image encoder and/or an image decoder, for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, is provided,
  • deblocking filter apparatus is configured to:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • deriving without using one or more refined Motion Vectors (such as a pair of refined MVs (e.g. refined MV0 for the first sub-block and refined MV1 for the second sub-block) or two pairs of refined MVs) , values of one or more filtering related parameters (such a boundary strength parameter and/or maximum filter length parameter) associated with the sub-block internal edge between the first sub-block and the second sub-block (or associated with the first sub-block and the second sub-block which are adjacent to the sub-block edge) under one or more first conditions; and
  • a deblocking filter apparatus for use in an image encoder and/or an image decoder, for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, is provided,
  • deblocking filter apparatus is configured to:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • initial Motion Vectors such as a pair of initial MVs (e.g. a first initial motion vector for the first sub-block and a second initial motion vector for the second sub-block) or two pairs of initial MVs)
  • filtering related parameters such as a boundary strength parameter
  • a deblocking filter apparatus for use in an image encoder and/or an image decoder, for deblocking a sub-block edge (or a sub-block internal edge or a sub-block internal boundary) between a first sub-block and a second sub-block of a current block, is provided,
  • deblocking filter apparatus is configured to:
  • motion vector refinement is enabled for the current block (or decoder side motion vector refinement (DMVR) is applied for the current block) (such as dmvr_Flag is equal to true or 1) ,
  • an encoder for encoding an image comprising a deblocking filter apparatus of any one of the preceding apparatus aspects.
  • a decoder for decoding an image comprising a deblocking filter apparatus of any one of the preceding apparatus aspects.
  • an encoding method for encoding an image comprising a deblocking method of any one of the preceding method aspects.
  • a decoding method for decoding an image comprising a deblocking method of any one of the preceding method aspects.
  • a decoder for decoding an image comprising: one or more processors;
  • a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, wherein the programming, when executed by the processors, configures the decoder to carry out the method according to any one of the preceding method aspects.
  • an encoder for encoding an image comprising: one or more processors;
  • a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, wherein the programming, when executed by the processors, configures the encoder to carry out the method according to any one of the preceding method aspects.
  • a computer program product is provided with a program code for performing the method according to any one of the preceding method aspects when the computer program runs on a computer.
  • a non-transitory computer-readable media storing computer instructions that when executed by one or more processors, cause the one or more processors to perform the method according to any one of the preceding method aspects.
  • x ?y: z If x is TRUE or not equal to 0, evaluates to the value of y; otherwise, evaluates to the value of z.
  • na When a relational operator is applied to a syntax element or variable that has been assigned the value "na” (not applicable) , the value “na” is treated as a distinct value for the syntax element or variable. The value “na” is considered not to be equal to any other value.
  • Bit-wise "or” When operating on integer arguments, operates on a two's complement representation of the integer value. When operating on a binary argument that contains fewer bits than another argument, the shorter argument is extended by adding more significant bits equal to 0.
  • x y Arithmetic right shift of a two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. Bits shifted into the most significant bits (MSBs) as a result of the right shift have a value equal to the MSB of x prior to the shift operation.
  • MSBs most significant bits
  • x y.. z x takes on integer values starting from y to z, inclusive, with x, y, and z being integer numbers and z being greater than y.
  • Asin (x) the trigonometric inverse sine function, operating on an argument x that is in the range of -1.0 to 1.0, inclusive, with an output value in the range of - ⁇ 2 to ⁇ 2, inclusive, in units of radians.
  • Atan (x) the trigonometric inverse tangent function, operating on an argument x, with an output value in the range of - ⁇ 2 to ⁇ 2, inclusive, in units of radians.
  • Ceil (x) the smallest integer greater than or equal to x.
  • Clip1 Y (x) Clip3 (0, (1 ⁇ BitDepth Y ) -1, x)
  • Clip1 C (x) Clip3 (0, (1 ⁇ BitDepth C ) -1, x)
  • Cos (x) the trigonometric cosine function operating on an argument x in units of radians.
  • Ln (x) the natural logarithm of x (the base-e logarithm, where e is the natural logarithm base constant 2.718 281 828... ) .
  • Tan (x) the trigonometric tangent function operating on an argument x in units of radians
  • the table below specifies the precedence of operations from highest to lowest; a higher position in the table indicates a higher precedence.
  • statement 1 If one or more of the following conditions are true, statement 1:
  • embodiments of the disclosure have been primarily described based on video coding, it should be noted that embodiments of the coding system 10, encoder 20 and decoder 30 (and correspondingly the system 10) and the other embodiments described herein may also be configured for still picture processing or coding, i.e. the processing or coding of an individual picture independent of any preceding or consecutive picture as in video coding.
  • inter-prediction units 244 (encoder) and 344 (decoder) may not be available in case the picture processing coding is limited to a single picture 17. All other functionalities (also referred to as tools or technologies) of the video encoder 20 and the video decoder 30 may equally be used for still picture processing, e.g.
  • residual calculation 204/304 transform 206, quantization 208, inverse quantization 210/310, (inverse) transform 212/312, partitioning 262, intra-prediction 254/354, and/or loop filtering 220, 320, and entropy coding 270 and entropy decoding 304.
  • Embodiments, e.g. of the encoder 20 and the decoder 30, and functions described herein, e.g. with reference to the encoder 20 and the decoder 30, may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted over communication media as one or more instructions or code and executed by a hardware-based processing unit.
  • Computer-readable media may include computer-readable storage media, which correspond to tangible media such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol.
  • computer-readable media generally may correspond to (1) tangible computer-readable storage media which are non-transitory or (2) a communication medium such as a signal or carrier wave.
  • Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure.
  • a computer program product may include a computer-readable medium.
  • Such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium.
  • coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.
  • DSL digital subscriber line
  • computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but are instead directed to non-transitory, tangible storage media.
  • Disk and disc include compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
  • processors such as one or more digital signal processors (DSPs) , general purpose microprocessors, application specific integrated circuits (ASICs) , field programmable logic arrays (FPGAs) , or other equivalent integrated or discrete logic circuitry.
  • DSPs digital signal processors
  • ASICs application specific integrated circuits
  • FPGAs field programmable logic arrays
  • processors may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein.
  • the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.
  • the techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set) .
  • IC integrated circuit
  • a set of ICs e.g., a chip set
  • Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and/or firmware.

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Abstract

La présente invention concerne un procédé et un appareil pour déterminer des paramètres associés à un filtrage pour effectuer un filtrage de déblocage sur un bord de sous-bloc entre un premier et un second sous-bloc d'une unité de codage et qui, même dans le cas d'un affinement de vecteur de mouvement, ne nécessite pas d'informations de mouvement affinées.
EP20870065.8A 2019-09-23 2020-09-21 Appareil et procédé permettant d'effectuer un déblocage Pending EP4022931A4 (fr)

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WO2024017004A1 (fr) * 2022-07-22 2024-01-25 Mediatek Inc. Réordonnancement de liste de référence dans un codage vidéo
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US9161046B2 (en) * 2011-10-25 2015-10-13 Qualcomm Incorporated Determining quantization parameters for deblocking filtering for video coding
US9756327B2 (en) * 2012-04-03 2017-09-05 Qualcomm Incorporated Quantization matrix and deblocking filter adjustments for video coding
US8629937B1 (en) * 2012-07-25 2014-01-14 Vixs Systems, Inc Motion adaptive filter and deinterlacer and methods for use therewith
US9872044B2 (en) * 2013-05-15 2018-01-16 Texas Instruments Incorporated Optimized edge order for de-blocking filter
EP3571844A1 (fr) * 2017-03-23 2019-11-27 Huawei Technologies Co., Ltd. Appareil et procédé de filtrage de dégroupage
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