Method and apparatus for deriving an interpolation filter index for a current block

Abstract

To provide a method, encoder, decoder, program, and storage medium for inter prediction improving the quality of a prediction signal and the coding efficiency.SOLUTION: A method for inter prediction includes: constructing a history-based motion information (HMI) candidate list; adding one or more history-based motion information candidates from the history-based motion information candidate list into a motion information candidate list for the block; and deriving motion information for the block based on the motion information candidate list. A half-pixel interpolation filter index is inherited when the history-based motion information candidate list is used, and a dedicated interpolation filter is selected instead of a default interpolation filter.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] Cross - Reference to Related Applications This patent application claims the priority of U.S. Provisional Patent Application No. 62 / 836,072, filed on April 19, 2019; U.S. Provisional Patent Application No. 62 / 845,938, filed on May 10, 2019; U.S. Provisional Patent Application No. 62 / 909,761, filed on October 2, 2019; and U.S. Provisional Patent Application No. 62 / 909,763, filed on October 2, 2019. The disclosures of the above - mentioned patent applications are hereby incorporated by reference in their entireties into this specification.

[0002] Embodiments of the present disclosure generally relate to the field of picture processing, and more particularly to inter - prediction, and in particular to methods and apparatuses for deriving an interpolation filter index for a current block, such as a merge procedure for parameters of a switchable interpolation filter.

Background Art

[0003] Video coding (video encoding and decoding) is used in a wide range of digital video applications, such as broadcast digital TV, video transmission over the Internet and mobile networks, real - time conversation applications such as video chat, video conferencing, DVDs and Blu - ray discs, video content acquisition and editing systems, and camcorders for security applications.

[0004] The amount of video data required to depict even relatively short videos can be quite large, which can pose difficulties when the data is to be streamed over a communication network with limited bandwidth capacity or transmitted in some other way. Thus, video data is generally compressed before being transmitted over modern communication networks. Since memory resources can be limited, the size of the video can also be a problem when the video is stored on a storage device. In many cases, video compression devices use software and / or hardware at the source to code the video data before transmission or storage, thereby reducing the amount of data required to represent the digital video image. Then, the compressed data is received at the destination by a video decompression device that decodes the video data. Due to limited network resources and the ever-increasing demand for higher video quality, improved compression and decompression techniques that increase the compression ratio without sacrificing much or any picture quality are desirable.

[0005] Recently, a switchable interpolation filter for half-pixel (half pel) positions has been introduced in Versatile Video Coding (VVC). The switching of the half pel luma interpolation filter is performed according to the accuracy of the motion vector. In the case of the accuracy of the half pel motion vector, an alternative half pel interpolation filter can be used, and the alternative half pel interpolation filter is indicated by an additional syntax element indicating which interpolation filter is used, thus increasing the signaling overhead. Summary of the Invention Means for Solving the Problems

[0006] Embodiments of the present application can achieve inheritance of half-pixel interpolation filter indexes when a history-based motion information candidate list is used, and thus a dedicated interpolation filter is selected instead of the default interpolation filter, and it aims to provide an apparatus and method for constructing a history-based motion information candidate list so as to improve the quality of the prediction signal and the coding efficiency.

[0007] Embodiments of the present application can achieve inheritance of half-pixel interpolation filter indexes when a history-based motion information candidate list is used, and thus aims to provide an apparatus and method for inter prediction for a current block coded in skip / merge mode so that the quality of the video signal can be improved.

[0008] The above and other objects are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the drawings.

[0009] According to a first aspect of the present invention, a method for constructing a history-based motion information (HMI) candidate list is provided, the method can be executed by an encoding device or a decoding device, and the method includes: a step of obtaining a history-based motion information candidate list, where the HMI list is an ordered list of N history-based motion information candidates H related to (or including) the motion information of a plurality of preceding blocks (for example, N preceding blocks) preceding the block, k = 0,..., N - 1, N is an integer greater than 0 (for example, N is an integer greater than 0 and less than or equal to a predefined number (0 < N <= 5)), and each history-based motion information candidate is an element, that is, k and N is an integer greater than 0 (for example, N is an integer greater than 0 and less than or equal to a predefined number (0 < N <= 5)), and each history-based motion information candidate is an element, that is, i) one or more motion vectors MV of the corresponding preceding block (such as luma motion vectors mvL0 and / or mvL1 with 1 / 16 fractional sample accuracy, where mvL0 and mvL1 correspond to the L0 and L1 reference picture lists), ii) one or more reference picture indices corresponding to the MV of the corresponding preceding block (such as reference picture indices refIdxL0 and / or refIdxL1, where refIdxL0 and refIdxL1 correspond to the L0 and L1 reference picture lists), and iii) an interpolation filter (IF) index (such as the IF index of the corresponding preceding block or the IF index related to the corresponding preceding block) including a step that includes the motion information of the corresponding preceding block, and a step of updating the HMI list based on the motion information of the block, where the motion information of the block includes elements, namely, i) one or more motion vectors MV of the block (such as luma motion vectors mvL0 and / or mvL1 with 1 / 16 fractional sample accuracy), ii) one or more reference picture indices corresponding to the MV of the block (such as reference indices refIdxL0 and / or refIdxL1), and iii) an interpolation filter index (such as the IF index of the block or the IF index related to the block) including a step, and including.

[0010] In an example, the interpolation filter (IF) index may refer to a fractional sample interpolation filter (IF) index. In particular, the IF index may refer to a half pixel (half pel) interpolation filter index or a half sample interpolation filter index (hpelIfIdx). The terms "half pixel interpolation filter" and "half sample interpolation filter" may be used interchangeably in this disclosure. The half sample interpolation filter index indicates a half pixel interpolation filter used to interpolate half pixel values when at least one of the motion vectors of the corresponding block points to a half pixel position. For example, if one or more motion vectors (MVs) (element i) of the motion information candidate based on history have at least one MV pointing to a half pixel position, the interpolation filter (IF) index (element iii) of the motion information candidate based on history indicates a half pixel interpolation filter used to interpolate half pixel values (i.e., the interpolation filter index (element iii) only affects the HMI candidate including half pel MVs). If one or more motion vectors (MVs) (element i) of the motion information candidate based on history do not have an MV pointing to a half pixel position, the interpolation filter (IF) index (element iii) of the motion information candidate based on history becomes meaningless (i.e., this IF index does not affect any non-half pel MVs, and the value of the IF index for non-half pel MVs has no meaning. Its value can be set to any value, for example, 0 / FALSE). In this case, the interpolation filter (IF) index (element iii) is assigned a default value that is not used in later steps. The same applies to the motion information of the block. In other words, the interpolation filter index (element iii) of the motion information of the block has meaning when at least one of the MVs of the block points to a half pixel position. If none of the MVs point to a half pixel position, the interpolation filter index (element iii) of the motion information is assigned a default value that is not used in later steps. In one exemplary implementation, the IF index is always stored in the HMI list regardless of the fractional part of the MV, even if the IF index is meaningless in some cases.The HMI list can be implemented in this way for the simplification of design. It can be understood that when neither of the MVs of both corresponding blocks points to the half-pixel position, the value assigned to the IF index has no effect on the decoding result.

[0011] In another exemplary implementation, the interpolation filter (IF) index can be replaced by the index of a set of interpolation filters (IF), and the index of the set of IFs indicates a switchable set of IFs among multiple sets of IFs. In the example, each set of IFs includes an interpolation filter for each fractional position. On the other hand, the IFs for the same fractional position can be equal among several sets of IFs. For example, there are the same filters for some fractional positions and different filters for some fractional positions among multiple sets of IFs, and in particular, the IFs for each fractional position can be switched according to the index of the set of IFs. In some cases, the switch between two sets of interpolation filters can be understood as the switch between two interpolation filters.

[0012] In one exemplary implementation, the half-pixel interpolation filter index indicates a half-pixel interpolation filter in a set of half-pixel interpolation filters, and the half-pixel interpolation filter is used to interpolate half-pixel values only when at least one of one or more motion vectors points to the half-pixel position. When the L0 and / or L1 motion vectors point to the half-pixel (half pel) position, the interpolation filter is selected according to the half-pixel interpolation filter index and used for the interpolation of samples during motion compensation for the corresponding prediction list (prediction direction) (L0 and / or L1).

[0013] It may be noted that a block and N previous blocks can be within a slice of a frame or can be within a frame. In an example, a history-based motion information candidate list (table) is emptied when reaching a new slice. When reaching a new slice, a construction process is called. In another example, an HMI list / table can be reset at each new CTU row within a slice.

[0014] It can be understood that the N previous blocks can be one or more previous blocks. A previous block refers to an already encoded or decoded block that is before the current block in encoding or decoding order. In an example, block P can use an HMVP table that includes one or more encoded / decoded blocks before block P. The HMVP table is updated after the derivation of the motion information of block P. After the HMVP table is updated, block Q following block P can use the updated HMVP table. Block Q is encoded or decoded after block P in decoding or encoding order.

[0015] It can be understood that after updating the HMVP list, it is possible that there are M history-based motion information candidates in the updated HMVP list, where M is less than or equal to a predefined number (such as 5) and M >= N.

[0016] When the index of the HMI list starts from 1, it can further be understood that the HMI list is an ordered list of N history-based motion information candidates H related to the motion information of a plurality of previous blocks preceding the block, where k = 1,..., N. k

[0017] ​Accordingly, an improved method is provided that enables inheritance of interpolation filter indexes within a history-based motion information candidate list. In particular, the interpolation filter (IF) index of a previous block is stored in the corresponding history-based motion information candidate within the history-based motion information candidate list. When the history-based motion information candidate list is used directly or indirectly for inter prediction of a block coded in merge or skip mode, the interpolation filter (IF) index can be borrowed from the corresponding motion information candidate without using a separate syntax element. Propagating the IF index through the history-based motion information candidate list enables the use of an appropriate interpolation filter (instead of using a predefined interpolation filter) for the block, which ensures the quality of the coded signal. As a result, the technology presented herein provides the advantage of improving coding efficiency and thus the overall compression performance of the video coding method.

[0018] It is noted that the terms "block", "coding block", or "picture block" as used in this disclosure may include a transform unit (TU), a prediction unit (PU), a coding unit (CU), etc. In versatile video coding (VVC), the transform unit and the coding unit are usually aligned, except for some scenarios, when TU tiling or sub block transform (SBT) is used. It can be understood that the terms "block", "picture block", "coding block", and "picture block" may be used interchangeably herein. The terms "sample" and "pixel" may also be used interchangeably in this disclosure. The terms "predicted sample value" and "predicted pixel value" may be used interchangeably in this disclosure. The terms "sample position" and "pixel position" may be used interchangeably in this disclosure.

[0019] It should be further understood that the terms "history-based motion information candidate list", "HMI list", "HMVP list", "HMVP table", and "HMVP LUT" can be used interchangeably in the present disclosure.

[0020] It should be understood that the HMVP list is constructed using the motion information of one or more coded / decoded previous blocks. The HMVP list is used to store motion information from neighboring blocks (but not necessarily from adjacent blocks as in the case of normal spatial merge candidates). The idea of HMVP is to use motion information from previous blocks that are spatially close to the block but not necessarily adjacent to it (blocks from some spatial neighborhood).

[0021] In a possible implementation form of the method according to the first aspect itself, the step of updating the HMI list is as follows for each history-based motion information candidate in the HMI list, that is, i) one or more motion vectors MV, and ii) one or more reference picture indices corresponding to the MV If at least one of them is different from the corresponding element of the block's motion information, add the block's motion information as the history-based motion information candidate H to the HMI list, including adding where k = N. k That is, it includes adding.

[0022] When the index of the HMI list starts from 1, adding can refer to adding the history-based motion information candidate H including the block's motion information to the HMI list, where k = N + 1. It can be understood that this means adding. k That is, it can be understood that this refers to adding.

[0023] It is possible to add the block's motion information as the history-based motion information candidate at the last position of the HMI list.

[0024] In a possible implementation form of the method according to the first aspect itself, the step of updating the HMI list is As a result of the comparison, the following elements of the motion information candidate based on the history of the HMI list, namely i) one or more motion vectors MV, and ii) one or more reference picture indices corresponding to the MV if they are the same as the corresponding elements of the motion information of the block, delete the motion information candidate based on the history from the HMI list, and add the motion information of the block to the HMI list as the motion information candidate H based on the history k including, where k = N - 1.

[0025] If the index of the HMI list starts from 1, adding may refer to adding the motion information of the block to the HMI list as the motion information candidate H based on the history, where k = N. k It can be understood that this can be referred to as adding.

[0026] The motion information of the block can be added as the motion information candidate based on the history at the last position of the HMI list.

[0027] In any of the above implementations of the first aspect or in a possible implementation form of the method according to the first aspect itself, the step of updating the HMI list is If N is equal to a predefined number, delete the motion information candidate H based on the history where k = 0 from the HMI list, and add the motion information of the block to the HMI list as the motion information candidate H based on the history where k = N - 1 k including the step of adding. k

[0028] If the index of the HMI list starts from 1, deleting may refer to deleting the motion information candidate H based on the history from the HMI list, where k = 1, and adding may refer to adding the motion information of the block to the HMI list as the motion information candidate H based on the history k k ​​which means adding when k = N, can be understood.

[0029] It is possible to delete the motion information candidate based on the history at the first position of the HMI list and add the motion information of the block as the motion information candidate based on the history at the last position of the HMI list.

[0030] In any of the above implementations of the first aspect or in a possible implementation form of the method according to the first aspect itself, the method includes a step of comparing whether the motion vector of the motion information candidate based on any history is the same as the corresponding motion vector of the block, and a step of comparing whether the reference picture index of the motion information candidate based on any history is the same as the corresponding reference picture index of the block.

[0031] In an alternative design, the method includes a step of comparing whether at least one of the motion vectors of the motion information candidates (i.e., HMVP candidates) based on each history is different from the corresponding motion vector of the block, and a step of comparing whether at least one of the reference picture indices of each HMVP candidate is different from the corresponding reference picture index of the block.

[0032] Therefore, it is made possible to use only the motion vectors (MVs) and reference picture indices in the pruning process while updating the HMVP table without comparing the interpolation filter indices. Therefore, a good trade-off between complexity and diversity of HMVP candidates can be achieved. In particular, enabling comparison based only on MVs and reference picture indices can avoid additional computational operations and reduce the computational complexity. Each comparison operation incurs additional computations during the HMVP table update process and the merge candidate construction process. Therefore, when the comparison operations can be reduced or eliminated, the computational complexity can be reduced, thereby enhancing the coding efficiency. Furthermore, enabling comparison based only on MVs and reference picture indices can maintain the diversity of HMVP records. Having two HMVP records with the same MVs and reference indices and only their interpolation filter (IF) indices being different is inefficient because these two records are not sufficiently different. Therefore, it is reasonable to consider these two HMVP records to be the same during the HMVP table update process. In this case, a new record that only differs from the existing record in terms of the IF index is not added to the HMVP table. As a result, the "old" / existing records that are "sufficiently different" (having different MVs or reference indices) from other records are maintained. In other words, for a new record to be added to the HMVP table, this new record should not only differ bitwise from the existing records but should be "significantly different". From the perspective of coding efficiency, it is more efficient to have two records with different MVs or reference indices in the HMVP table rather than two records that only differ in terms of the IF index.

[0033] In a possible implementation form of the method according to any of the above-described implementations of the first aspect or the first aspect itself, the predefined number is 5 or 6.

[0034] In any of the above implementations of the first aspect or in a possible implementation form of the method according to the first aspect itself, the half-sample interpolation filter index included in the motion information candidate based on history indicates a half-sample interpolation filter among a set of half-sample interpolation filters, and the half-sample interpolation filter is applied to interpolate half-sample values only when at least one of one or more MVs of the motion information candidate based on history points to a half-sample position.

[0035] In the prior art, the default IF index (corresponding to the default IF) was always used for the merge candidates obtained from the HMVP table. According to the present invention, the IF index is propagated through the HMVP table, and thus, one of a set of interpolation filters can be used according to the IF index. In an example, one of two interpolation filters (the default interpolation filter and the alternative interpolation filter) can be used according to the IF index. Therefore, a dedicated interpolation filter is selected instead of the default interpolation filter, which in turn enhances the reliability of the reference and thus improves the quality of the predicted signal and the coding efficiency.

[0036] It is noted that the terms "alternative half-pixel interpolation filter", "switchable interpolation filter (SIF)", or "half-pixel interpolation filter" can be used interchangeably in the present disclosure.

[0037] An appropriate interpolation filter (IF) can be selected according to the content. For regions with sharp edges, an IF based on the normal DCT can be used. For smooth regions (or when it is not necessary to maintain sharp edges), an alternative 6-tap IF (Gaussian filter) can be used. For the merge mode, this IF index is borrowed from the corresponding motion information candidate. For a block coded in the merge mode, when the motion information candidate is obtained from the HMVP table, an alternative IF can be used. Propagating the IF index through the HMVP table enables the use of an appropriate IF for the block. This brings the advantage of improving the coding efficiency. Without the proposed mechanism, the default IF index (corresponding to the 8-tap DCT-based IF) would always be used for the HMVP merge candidate, and the details of the content of the current block (whether sharp edges need to be maintained) could not be considered.

[0038] According to a second aspect of the present invention, a method for inter prediction for a block within a frame of a video signal is provided, the method comprising: constructing a history-based motion information candidate (HMI) list, the HMI list being an ordered list of N history-based motion information candidates H related to (or including) the motion information of a plurality of preceding blocks (e.g., N preceding blocks) preceding the block, where k = 0,..., N - 1, N is an integer greater than 0, and each history-based motion information candidate corresponds to a preceding block and comprises elements, namely: k i) one or more motion vectors MV of the preceding block, ii) one or more reference picture indices corresponding to the MV of the preceding block, and iii) an interpolation filter index (such as the interpolation filter index of the preceding block or the interpolation filter index related to the preceding block), and including; The step of adding movement information candidates based on one or more histories from the HMI list to the movement information candidate list for the block, The step of deriving movement information for the block based on the movement information candidate list, is included.

[0039] The movement information candidate list can be a merge candidate list.

[0040] In an alternative or additional design, according to a second aspect of the present invention, a method for inter prediction for a block within a frame of a video signal is provided, the method comprising: The step of constructing a movement information candidate list based on history, wherein the HMI list is based on N histories related to (or including) the movement information of a plurality of preceding blocks (e.g., N preceding blocks) preceding the block, and the movement information candidate H k is an ordered list, where k = 0,..., N - 1, N is an integer greater than 0, and at least one movement information candidate based on history is i) one or more motion vectors (MVs), where at least one of the MVs points to a half-pixel position, one or more motion vectors (MVs), ii) one or more reference picture indices corresponding to one or more MVs, and iii) the interpolation filter index of the preceding block including elements for the corresponding preceding block, the step of, The step of adding movement information candidates based on one or more histories from the HMI list to the movement information candidate list for the block, The step of deriving movement information for the block based on the movement information candidate list.

[0041] The movement information candidate list can be a merge candidate list.

[0042] It can be understood that the history-based motion information candidate is added as a history-based merge candidate to the merge candidate list.

[0043] In an example, the HMI list has a length of N, where N is 5 or 6.

[0044] Accordingly, an improved method is provided that enables inheritance of the interpolation filter index within the history-based motion information candidate list. In particular, the interpolation filter (IF) index of the previous block is stored in the corresponding history-based motion information candidate within the history-based motion information candidate list. When the history-based motion information candidate list is used directly or indirectly for inter-prediction of a block coded in merge or skip mode, the interpolation filter (IF) index can be borrowed from the corresponding motion information candidate without using a separate syntax element. Propagating the IF index through the history-based motion information candidate list enables the use of an appropriate interpolation filter (instead of using a predefined interpolation filter) for the block, which guarantees the quality of the coded signal. As a result, the technology presented herein provides the advantage of improving coding efficiency and thus the overall compression performance of the video coding method.

[0045] In a possible implementation form of the method according to the second aspect itself, the half-sample interpolation filter is applied only when at least one of the one or more MVs of the derived motion information points to a half-sample position, and the half-sample interpolation filter is indicated by the half-sample interpolation filter index included in the derived motion information.

[0046] In any of the above implementations of the second aspect or in a possible implementation form of the method according to the second aspect itself, the half-sample interpolation filter index included in the history-based motion information candidate indicates a half-sample interpolation filter among a set of half-sample interpolation filters, and the half-sample interpolation filter is applied to interpolate half-sample values only when at least one of one or more MVs of the history-based motion information candidate points to a half-sample position.

[0047] In any of the above implementations of the second aspect or in a possible implementation form of the method according to the second aspect itself, the history-based motion information candidate further includes one or more bi-prediction weight indexes. The term bi-prediction weight index bcw_idx is also referred to as a generalized bi-prediction weight index GBIdx and / or a CU-level weighted bi-prediction (BCW: Bi-prediction with CU-level Weights) index. Alternatively, this index may be simply referred to as BWI, which is abbreviated as the bi-prediction weight index.

[0048] In any of the above implementations of the second aspect or in a possible implementation form of the method according to the second aspect itself, For each history-based motion information candidate in the HMI list, i.e., i) one or more motion vectors MV, and ii) one or more reference picture indexes corresponding to the MV if at least one of them is different from the corresponding element of the block's motion information, add the block's motion information to the HMI list as a history-based motion information candidate H k and further including adding, where k = N.

[0049] In any of the above implementations of the second aspect or in a possible implementation form of the method according to the second aspect itself, The following elements of the motion information candidates based on the HMI list history, namely, i) one or more motion vectors MV, and ii) one or more reference picture indices corresponding to the MV are the same as the corresponding elements of the block motion information, the motion information candidates based on the history are deleted from the HMI list, and the block motion information is added to the HMI list as the motion information candidates based on the history H k where k = N - 1, further including adding.

[0050] In any of the above implementations of the second aspect or in a possible implementation form of the method according to the second aspect itself, if N is equal to a predefined number, the motion information candidates based on the history with k = 0, H k are deleted from the HMI list, and the block motion information is added to the HMI list as the motion information candidates based on the history H with k = N - 1 k further including the step of adding. In the example, the predefined number is 5.

[0051] In any of the above implementations of the second aspect or in a possible implementation form of the method according to the second aspect itself, the method further includes the step of comparing whether the corresponding motion vector of any motion information candidate based on the history is the same as the block motion vector, and the step of comparing whether the corresponding reference picture index of any motion information candidate based on the history is the same as the block reference picture index.

[0052] In an alternative design, the comparing step includes comparing whether at least one of the motion vectors of each motion information candidate based on the history is different from the corresponding motion vector of the block, and the step of comparing whether at least one of the reference picture indices of each HMVP candidate is different from the corresponding reference picture index of the block.

[0053] In a possible implementation form of the method according to any of the above implementations of the second aspect or the second aspect itself, the motion information candidate list is used for the merge mode or the skip mode. In other words, the current block is coded in the merge mode or the skip mode.

[0054] In a possible implementation form of the method according to any of the above implementations of the second aspect or the second aspect itself, the step of deriving motion information for a block based on the motion information candidate list includes deriving, as the motion information of the current block, the motion information referred to by the candidate index from the motion information candidate list, where the candidate index is parsed or derived from the bitstream.

[0055] In a possible implementation form of the method according to any of the above implementations of the second aspect or the second aspect itself, a step of obtaining a predicted sample value of a block by applying a half-pixel interpolation filter to a pixel value of a reference picture pointed to by an MV when at least one of one or more motion vectors MV included in the derived motion information points to a half-pixel position, where the half-pixel interpolation filter is indicated by an interpolation filter index included in the derived motion information, and when the motion vector MV included in the derived motion information does not point to a half-pixel position, further includes a step of obtaining a predicted sample value of the block by applying a default interpolation filter to the pixel value of the reference picture pointed to by the MV.

[0056] The encoding method and the decoding method defined in the claims, the description, and the figures can be respectively executed by an encoding device and a decoding device.

[0057] According to a third aspect of the present invention, a motion information candidate list based on a device history for construction is provided, and the device A history-based motion information candidate list acquisition unit configured to acquire a history-based motion information candidate list, wherein the HMI list is a list of N history-based motion information candidates H related to the motion information of a plurality of blocks preceding the block k in sorted order, where k = 0,..., N-1, N is an integer greater than 0, and each history-based motion information candidate comprises elements, namely i) one or more motion vectors MV, ii) one or more reference picture indices corresponding to the MV, and iii) an interpolation filter index and a history-based motion information candidate list acquisition unit; A history-based motion information candidate list update unit configured to update the HMI list based on the motion information of the block, wherein the motion information of the block comprises elements, namely i) one or more motion vectors MV, ii) one or more reference picture indices corresponding to the MV, and iii) an interpolation filter index and a history-based motion information candidate list update unit.

[0058] The method according to the first aspect of the present invention can be executed by the apparatus according to the third aspect of the present invention. Further features and implementation forms of the apparatus according to the third aspect of the present invention correspond to the features and implementation forms of the apparatus according to the first aspect of the present invention.

[0059] According to a fourth aspect of the present invention, there is provided an apparatus for inter prediction for a block, the apparatus comprising a list management unit configured to construct a history-based motion information candidate list, wherein the HMI list is a list of N history-based motion information candidates H related to the motion information of a plurality of blocks preceding the block kis an ordered list, where k = 0, ..., N - 1, N is an integer greater than 0, and the motion information candidate based on each history is an element, i.e., i) one or more motion vectors MV, ii) one or more reference picture indices corresponding to the MV, and iii) an interpolation filter index including, and a list management unit further configured to add the motion information candidates based on one or more histories from the HMI list to the motion information candidate list for the block, a list management unit, a motion information derivation unit configured to derive the motion information for the block based on the motion information candidate list, including.

[0060] The method according to the second aspect of the present invention can be executed by the apparatus according to the fourth aspect of the present invention. Further features and implementation forms of the apparatus according to the fourth aspect of the present invention correspond to the features and implementation forms of the apparatus according to the second aspect of the present invention.

[0061] According to a fifth aspect, the present invention relates to an encoder (20) including a processing circuit for executing the method according to the first or second aspect itself or an implementation form thereof.

[0062] According to a sixth aspect, the present invention relates to a decoder (30) including a processing circuit for executing the method according to the first or second aspect itself or an implementation form thereof.

[0063] According to a seventh aspect, the present invention relates to a decoder. The decoder includes one or more processors, A non-transitory computer-readable storage medium coupled to a processor and storing programming for execution by the processor, the programming configuring a decoder to perform a method according to the first or second aspect itself or in the form of their implementation when executed by the processor, and a non-transitory computer-readable storage medium.

[0064] According to an eighth aspect, the present invention relates to an encoder. The encoder one or more processors, and a non-transitory computer-readable storage medium coupled to the processor and storing programming for execution by the processor, the programming configuring the encoder to perform a method according to the first or second aspect itself or in the form of their implementation when executed by the processor, and a non-transitory computer-readable storage medium.

[0065] According to a ninth aspect, the present invention relates to a non-transitory storage medium including a bitstream encoded / decoded by any one of the methods of the above-described aspects.

[0066] An apparatus for encoding or decoding a video stream may include a processor and a memory. The memory stores instructions for causing the processor to execute a method according to any one of the above-described aspects.

[0067] For each of the encoding or decoding methods disclosed herein, a computer-readable storage medium is proposed, and the storage medium stores instructions thereon for causing one or more processors to encode or decode video data when executed. The instructions cause one or more processors to execute a method according to any one of the above-described aspects.

[0068] Furthermore, for each of the encoding or decoding methods disclosed herein, a computer program product is proposed. The computer program product includes program code for executing a method according to any one of the above-described aspects.

[0069] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

[0070] Embodiments of the invention are described in more detail below with reference to the accompanying figures and drawings.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0072] Hereinafter, the same reference numerals refer to the same or at least functionally equivalent features unless otherwise specified.

[0073] In the following description, reference is made to the accompanying drawings that form a part hereof and which illustrate specific aspects of embodiments of the invention or specific aspects in which embodiments of the invention may be used. It is understood that embodiments of the invention may be used in other aspects and may include structural or logical changes not shown in the drawings. Accordingly, the following detailed description should not be construed in a limiting sense, and the scope of the invention is defined by the appended claims.

[0074] For example, it is understood that the disclosure related to the methods described may equally apply to corresponding devices or systems configured to perform the methods, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units for performing the one or more method steps described, such as functional units (e.g., one unit for performing one or more steps, or multiple units each performing one or more of the multiple steps), even if such one or more units are not explicitly described or shown in the figures. On the other hand, for example, if a specific device is described based on one or more units, such as functional units, the corresponding method may include one step for performing the functions of the one or more units (e.g., one step for performing the functions of one or more units, or multiple steps each performing one or more of the functions of one or more of the multiple units), even if such one or more steps are not explicitly described or shown in the figures. Further, it is understood that the various exemplary embodiments and / or aspects described herein may be combined with each other unless otherwise specified.

[0075] Video coding generally refers to the processing of a sequence of pictures that form a video or video sequence. Instead of the term "picture", the terms "frame" or "image" may be used synonymously in the field of video coding. Video coding (or generally coding) includes two parts, video encoding and video decoding. Video encoding is performed on the source side and generally includes processing the original video picture (e.g., by compression) to reduce the amount of data required to represent the video picture (for more efficient storage and / or transmission). Video decoding is performed on the destination side and generally includes performing the reverse process compared to the encoder to reconstruct the video picture. Embodiments that refer to the "coding" of a video picture (or generally a picture) are understood to relate to the "encoding" or "decoding" of the video picture or each video sequence. The combination of the encoding part and the decoding part is also called a codec (coding and decoding).

[0076] In the case of reversible video coding, the original video picture can be reconstructed (assuming no transmission loss or other data loss during storage or transmission), that is, the reconstructed video picture has the same quality as the original video picture. In the case of irreversible video coding, in order to reduce the amount of data representing the video picture, for example, further compression by quantization is performed, which cannot be fully reconstructed at the decoder, that is, the quality of the reconstructed video picture is lower or worse than the quality of the original video picture.

[0077] Some video coding standards belong to the group of "irreversible hybrid video coders" (i.e., they combine spatial and temporal prediction in the sample domain with 2D transform coding for applying quantization in the transform domain). Each picture of a video sequence is generally partitioned into a set of non-overlapping blocks, and coding is generally performed at the block level. In other words, in the encoder, the video generally generates a prediction block using, for example, spatial (intra-picture) prediction and / or temporal (inter-picture) prediction, subtracts the prediction block from the current block (the block being currently processed / processed), obtains a residual block, transforms the residual block, and quantizes the residual block in the transform domain to reduce the amount of data to be transmitted (compressed), i.e., coded, at the block (video block) level. On the other hand, in the decoder, the inverse process compared to the encoder is applied to the coded or compressed block to reconstruct the current block for presentation. Further, the encoder duplicates the decoder's processing loop so that both generate the same prediction (e.g., intra and inter prediction) and / or reconstruction for processing, i.e., coding, subsequent blocks.

[0078] Embodiments of a video coding system 10, a video encoder 20, and a video decoder 30 are described below with reference to FIGS. 1 through 3.

[0079] FIG. 1A is a schematic block diagram showing an exemplary coding system 10 that may utilize the techniques of the present application, e.g., a video coding system 10 (or simply coding system 10). The video encoder 20 (or simply encoder 20) and the video decoder 30 (or simply decoder 30) of the video coding system 10 are examples of devices that may be configured to perform the techniques according to various examples described in the present application.

[0080] As shown in FIG. 1A, the coding system 10 includes a source device 12 configured to provide, for example, encoded picture data 21 to a destination device 14 in order to decode the encoded picture data 13.

[0081] The source device 12 includes an encoder 20 and additionally, i.e., optionally, may include a picture source 16, a pre-processor (or pre-processing unit) 18, for example, a picture pre-processor 18, and a communication interface or communication unit 22.

[0082] The picture source 16 may include or be any kind of picture capturing device, such as a camera for capturing pictures of the real world, and / or any kind of picture generating device, such as a computer graphics processor for generating pictures animated by a computer, or any kind of other device for acquiring and / or providing real world pictures, pictures generated by a computer (e.g., screen content, virtual reality (VR) pictures), and / or any combination thereof (e.g., augmented reality (AR) pictures). The picture source may be or be any kind of memory or storage device for storing any of the above-described pictures.

[0083] Distinguished from the processing performed by the pre-processor 18 and the pre-processing unit 18, the picture or picture data 17 may also be referred to as raw picture or raw picture data 17.

[0084] The preprocessor 18 is configured to receive the (raw) picture data 17 and perform preprocessing on the picture data 17 to obtain the preprocessed picture 19 or the preprocessed picture data 19. The preprocessing performed by the preprocessor 18 may include, for example, trimming, color format conversion (e.g., from RGB to YCbCr), color correction, or noise removal. It can be understood that the preprocessing unit 18 can be any component.

[0085] The video encoder 20 is configured to receive the preprocessed picture data 19 and provide the encoded picture data 21 (further details will be described below, for example, based on FIG. 2).

[0086] The communication interface 22 of the source device 12 is configured to receive the encoded picture data 21 and transmit the encoded picture data 21 (or any further processed version thereof) via the communication channel 13 to another device, such as the destination device 14 or any other device, for storage or direct reconstruction.

[0087] The destination device 14 includes a decoder 30 (e.g., a video decoder 30), and additionally, i.e., optionally, may include a communication interface or communication unit 28, a postprocessor 32 (or postprocessing unit 32), and a display device 34.

[0088] The communication interface 28 of the destination device 14 is configured to receive the encoded picture data 21 (or any further processed version thereof), for example, directly from the source device 12 or from any other source, such as a storage device, e.g., a storage device of the encoded picture data, and provide the encoded picture data 21 to the decoder 30.

[0089] Communication interfaces 22 and 28 may be configured to transmit or receive encoded picture data 21 or encoded data 13 between source device 12 and destination device 14 via a direct communication link, such as a direct wired or wireless connection, or via any type of network, such as a wired or wireless network or any combination thereof, or any type of private and public network, or any combination of any type thereof.

[0090] Communication interface 22 may be configured to process encoded picture data, for example, by packaging the encoded picture data 21 into a suitable format, such as a packet, and / or using any type of transmission encoding or processing for transmission via a communication link or communication network.

[0091] Communication interface 28, which forms the counterpart of communication interface 22, may be configured to receive the transmitted data and process the transmitted data using any type of corresponding transmission decoding or processing and / or unpackaging to obtain the encoded picture data 21.

[0092] Both communication interface 22 and communication interface 28 can be configured as a unidirectional communication interface or a bidirectional communication interface indicated by an arrow regarding communication channel 13 in FIG. 1A pointing from source device 12 towards destination device 14, and may be configured to, for example, set up a connection, verify any other information related to the communication link and / or data transmission, such as the transmission of encoded picture data, and communicate, for example, by sending and receiving messages.

[0093] Decoder 30 is configured to receive the encoded picture data 21 and provide the decoded picture data 31 or the decoded picture 31 (further details will be described below, for example, based on FIG. 3 or FIG. 5).

[0094] The post-processor 32 of the destination device 14 is configured to post-process the decoded picture data 31 (also referred to as the reconstructed picture data), for example, the decoded picture 31, to obtain the post-processed picture data 33, for example, the post-processed picture 33. The post-processing executed by the post-processing unit 32 may include, for example, color format conversion (e.g., from YCbCr to RGB), color correction, trimming, or resampling, or any other processing for preparing the decoded picture data 31, for example, for display by the display device 34.

[0095] The display device 34 of the destination device 14 is configured to receive the post-processed picture data 33 for displaying a picture to a user or viewer, for example. The display device 34 may be any type of display for showing the reconstructed picture, for example, an integrated or external display or monitor, or may include such a display or monitor. The display may include, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (LCoS), a digital light processor (DLP), or any other type of display.

[0096] Figure 1A shows the source device 12 and the destination device 14 as separate devices, but embodiments of the device may include both or both functions, the source device 12 or corresponding functions and the destination device 14 or corresponding functions. In such embodiments, the source device 12 or corresponding functions and the destination device 14 or corresponding functions may be implemented using the same hardware and / or software or by separate hardware and / or software or any combination thereof.

[0097] As will be apparent to those skilled in the art based on the description, the functions of the different units or the presence and (exact) partitioning of the functions within the source device 12 and / or destination device 14 shown in Figure 1A may vary depending on the actual device and application.

[0098] The encoder 20 (e.g., video encoder 20) or decoder 30 (e.g., video decoder 30) or both the encoder 20 and decoder 30 can be implemented by a processing circuit such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, or any combination thereof dedicated to or for video coding, as shown in FIG. 1B. The encoder 20 can be implemented by the processing circuit 46 to embody various modules considered in relation to the encoder 20 of FIG. 2 and / or any other encoder system or subsystem described herein. The decoder 30 can be implemented by the processing circuit 46 to embody various modules considered in relation to the decoder 30 of FIG. 3 and / or any other decoder system or subsystem described herein. The processing circuit can be configured to perform various operations considered later. As shown in FIG. 5, when the technology is implemented partially in software, the device can store instructions for the software in a suitable non-transitory computer-readable storage medium and execute the instructions in hardware using one or more processors to perform the technology of the present disclosure. Either the video encoder 20 or the video decoder 30 can be incorporated, for example, as part of a combined encoder / decoder (codec) within a single device as shown in FIG. 1B.

[0099] Source device 12 and destination device 14 can include any of a wide range of devices, such as any type of handheld or fixed device, e.g., a notebook or laptop computer, a mobile phone, a smartphone, a tablet or tablet computer, a camera, a desktop computer, a set-top box, a television, a display device, a digital media player, a video game console, a video streaming device (such as a content service server or a content delivery server), a broadcast receiver device, a broadcast transmitter device, etc., and may or may not use an operating system or may use any type of operating system. In some cases, source device 12 and destination device 14 may be capable of wireless communication. Thus, source device 12 and destination device 14 can be wireless communication devices.

[0100] In some cases, the video coding system 10 shown in FIG. 1A is merely an example, and the techniques of the present disclosure can be applied to video coding situations (e.g., video encoding or video decoding) that do not necessarily include any data communication between an encoding device and a decoding device. In other examples, data is retrieved from local memory or streamed over a network, etc. A video encoding device can encode data and store it in memory and / or a video decoding device can retrieve and decode data from memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other and simply encode data in and / or retrieve and decode data from memory.

[0101] For the sake of convenience of description, embodiments of the present invention are described herein by referring to, for example, the reference software of the next-generation video coding standard developed by the Joint Collaboration Team on Video Coding (JCT-VC) of the ITU-T Video Coding Experts Group (VCEG) and the ISO / IEC Moving Picture Experts Group (MPEG), such as High-Efficiency Video Coding (HEVC) or Versatile Video Coding (VVC). Those skilled in the art will understand that the embodiments of the present invention are not limited to HEVC or VVC.

[0102] Encoder and encoding method FIG. 2 shows a schematic block diagram of an exemplary video encoder 20 configured to implement the technology of the present application. In the example of FIG. 2, the video encoder 20 includes an input 201 (or input interface 201), a residual calculation unit 204, a transformation processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transformation 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). The video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder by a hybrid video codec.

[0103] The residual calculation unit 204, the conversion processing unit 206, the quantization unit 208, and the mode selection unit 260 can be regarded as forming the forward signal path of the encoder 20. On the other hand, the inverse quantization unit 210, the inverse conversion processing unit 212, the reconstruction unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244, and the intra prediction unit 254 can be regarded as forming the reverse signal path of the video encoder 20. The reverse signal path of the video encoder 20 corresponds to the signal path of the decoder (see the video decoder 30 in FIG. 3). The inverse quantization unit 210, the inverse conversion 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 regarded as forming the "built-in decoder" of the video encoder 20.

[0104] Picture & Picture Classification (Picture & Block) The encoder 20 can be configured to receive, for example, Picture 17 (or Picture Data 17) via the input 201, for example, a sequence of pictures forming a video or a video sequence. The received picture or picture data may be the preprocessed Picture 19 (or preprocessed Picture Data 19). For simplicity, the following description refers to Picture 17. Picture 17 can also be called the current picture or the picture to be coded (especially in video coding, to distinguish the current picture from other pictures, for example, the already encoded and / or decoded pictures of the same video sequence, that is, the video sequence including the current picture).

[0105] (Digital) pictures can or may be considered as a two-dimensional array or matrix of samples having intensity values. Samples of the array can also be called pixels (short for picture elements) or pels. The number of samples in the horizontal and vertical directions (or axes) of the array or picture defines the size and / or resolution of the picture. For color representation, generally three color components are used, i.e., the picture can be represented or can include three sample arrays. In the RGB format or color space, the picture includes corresponding sample arrays of red, green, and blue. However, in video coding, each pixel generally includes a luminance component represented by Y (L may also be used instead) and two chrominance components represented by Cb and Cr, and is represented in YCbCr. The luminance (or short for luma) component Y represents brightness or intensity of gray levels (similar to, for example, a grayscale picture), while the two chrominance (or short for chroma) components Cb and Cr represent chrominance or color information components. Thus, a picture in the YCbCr format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (Cb and Cr). A picture in the RGB format can be converted or transformed to the YCbCr format, and vice versa, and the process is also known as color transformation or conversion. If the picture is monochrome, the picture can include only a luminance sample array. Thus, the picture can be, for example, an array of luma samples in the monochrome format, or an array of luma samples and two corresponding arrays of chroma samples in the 4:2:0, 4:2:2, and 4:4:4 color formats.

[0106] An embodiment of the video encoder 20 may include a picture partitioning unit (not shown in FIG. 2) configured to partition picture 17 into a plurality of (usually non-overlapping) picture blocks 203. These blocks may also be referred to as root blocks, macroblocks (H.264 / AVC), or coding tree blocks (CTB) or coding tree units (CTU) (H.265 / HEVC and VVC). The picture partitioning unit may use the same block size with respect to a corresponding grid that defines all pictures and block sizes of the video sequence, or may vary the block size between pictures or subsets or groups of pictures and be configured to partition each picture into corresponding blocks.

[0107] In a further embodiment, the video encoder may be configured to directly receive blocks 203 of picture 17, for example, one, some, or all of the blocks that form picture 17. Picture block 203 may also be referred to as the current picture block or the picture block to be coded.

[0108] Similar to picture 17, picture block 203 may also be regarded or regarded as a two-dimensional array or matrix of samples that is smaller in dimension than picture 17 but has intensity values (sample values). In other words, block 203 may include, for example, one sample array (e.g., the luma array in the case of a monochrome picture 17, or the luma or chroma arrays in the case of a color picture), or three sample arrays (e.g., the luma and two chroma arrays in the case of a color picture 17), or any other number and / or type of arrays, depending on the color format applied. The number of samples in the horizontal and vertical directions (or axes) of block 203 defines the size of block 203. Thus, the block may be, for example, an MxN (M columns × N rows) array of samples or an MxN array of transform coefficients.

[0109] The embodiment of the video encoder 20 shown in FIG. 2 can be configured to encode picture 17 block by block. For example, encoding and prediction are performed for each block 203.

[0110] Calculation of Residual The residual calculation unit 204 can be configured to calculate a residual block 205 (also referred to as residual 205) based on a picture block 203 and a prediction block 265 (further details about the prediction block 265 will be given later) by, for example, subtracting the sample values of the prediction block 265 from the sample values of the picture block 203 for each sample (for each pixel) in the sample area to obtain the residual block 205 in the sample area.

[0111] Transformation The transformation processing unit 206 can be configured to apply a transformation, such as a discrete cosine transform (DCT) or a discrete sine transform (DST), to the sample values of the residual block 205 to obtain transformation coefficients 207 in the transformation domain. The transformation coefficients 207, also referred to as transformed residual coefficients, can represent the residual block 205 in the transformation domain.

[0112] The conversion processing unit 206 may be configured to apply integer approximations of DCT / DST such as the conversion defined for H.265 / HEVC. Compared with the orthogonal DCT transform, such integer approximations are generally scaled at a specific rate. To maintain the norm of the residual blocks processed by the forward and inverse transforms, an additional scaling factor is applied as part of the conversion process. The scaling factor is generally selected based on specific constraints such as the scaling factor being a power of two for shift operations, the bit depth of the conversion coefficients, and the trade-off between accuracy and implementation cost. For example, a specific scaling factor may be specified for the inverse transform by the inverse transform processing unit 212 (and for example, the corresponding inverse transform by the inverse transform processing unit 312 in the video decoder 30), and for example, the corresponding scaling factor for the forward transform by the conversion processing unit 206 of the encoder 20 may be specified accordingly.

[0113] Embodiments of the video encoder 20 (each, the conversion processing unit 206) may be configured to output conversion parameters, for example, of a certain type of one conversion or a plurality of conversions, such that the video decoder 30 can receive and use the conversion parameters for decoding, for example, as they are or encoded or compressed by the entropy encoding unit 270.

[0114] Quantization The quantization unit 208 may be configured to obtain the quantized coefficients 209 by quantizing the conversion coefficients 207, for example, by applying scalar quantization or vector quantization. The quantized coefficients 209 may also be referred to as quantized conversion coefficients 209 or quantized residual coefficients 209.

[0115] The quantization process may reduce the bit depth associated with some or all of the conversion coefficients 207. For example, an n-bit conversion coefficient can be truncated to an m-bit conversion coefficient during quantization, where n is greater than m. The degree of quantization can be adjusted by adjusting the quantization parameter (QP). For example, for scalar quantization, different scalings can be applied to achieve finer or coarser quantization. A smaller quantization step size corresponds to finer quantization, while a larger quantization step size corresponds to coarser quantization. The applicable quantization step size can be indicated by the quantization parameter (QP). The quantization parameter can be, for example, an index to a predefined set of applicable quantization step sizes. For example, a small quantization parameter can correspond to fine quantization (small quantization step size), a large quantization parameter can correspond to coarse quantization (large quantization step size), or vice versa. Quantization can include division by the quantization step size. For example, the corresponding and / or inverse dequantization by the inverse quantization unit 210 can include multiplication by the quantization step size. Some standards, such as embodiments according to HEVC, can be configured to determine the quantization step size using the quantization parameter. Generally, the quantization step size can be calculated based on the quantization parameter using a fixed point approximation of an equation that includes division. Additional scaling factors can be introduced for quantization and dequantization to restore the norm of the residual block that can be modified due to the scaling used in the fixed point approximation of the equations for the quantization step size and quantization parameter. In one exemplary implementation, the scaling of the inverse transform and dequantization can be combined. Alternatively, a customized quantization table can be used, for example, signaled from the encoder to the decoder within the bitstream. Quantization is an irreversible operation, and the loss increases as the quantization step size increases.

[0116] Embodiments of the video encoder 20 (each quantization unit 208), for example, may be configured to output quantization parameters (QP) that are, for example, unchanged or encoded by the entropy encoding unit 270 so that the video decoder 30 can receive and apply them for decoding.

[0117] Inverse quantization The inverse quantization unit 210 is configured to apply inverse quantization of the quantization unit 208 to the quantized coefficients to obtain dequantized coefficients 211, for example, by applying the inverse of the quantization method applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208. The dequantized coefficients 211, also referred to as dequantized residual coefficients 211, may correspond to the transform coefficients 207, although generally not identical to the transform coefficients due to loss by quantization.

[0118] Inverse transformation The inverse transformation processing unit 212 is configured to apply an inverse transformation of the transformation applied by the transformation processing unit 206, for example, an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST) or other inverse transformation, 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.

[0119] Reconstruction The reconstruction unit 214 (for example, an adder or accumulator 214) is configured to add the transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265 by adding the sample values of the reconstructed residual block 213 and the sample values of the prediction block 265, sample by sample, to obtain a reconstructed block 215 in the sample domain.

[0120] Filtering The loop filter unit 220 (or simply "loop filter" 220) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or generally, to filter the reconstructed samples to obtain filtered samples. The loop filter unit is configured to, for example, smooth pixel transitions or otherwise improve the quality of the video. The loop filter unit 220 may include a deblocking filter, a sample - adaptive offset (SAO) filter, or one or more other filters, such as a bilateral filter, an adaptive loop filter (ALF), sharpening, a smoothing filter, or a collaborative filter, or any combination thereof. The loop filter unit 220 is shown as an in - loop filter in FIG. 2, but 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 the filtered reconstructed block 221.

[0121] Embodiments of the video encoder 20 (each, the loop filter unit 220) may be configured to output the parameters of the loop filter, such as the same loop filter parameters or respective loop filters, for example, as is or encoded by the entropy encoding unit 270, such that the decoder 30 can receive and apply them for decoding.

[0122] Decoded picture buffer The decoded picture buffer (DPB) 230 can be a memory that stores reference pictures or generally reference picture data for encoding video data by the video encoder 20. The DPB 230 can be formed by any of various 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. The decoded picture buffer (DPB) 230 can be configured to store one or more filtered blocks 221. The decoded picture buffer 230 can be further configured to store the same current picture or a different picture, for example, other already filtered blocks of an already reconstructed picture, for example, already reconstructed and filtered blocks 221, and can provide, for example, for inter prediction, a completely already reconstructed, i.e., decoded picture (and corresponding reference blocks and samples) and / or a partially reconstructed current picture (and corresponding reference blocks and samples). The decoded picture buffer (DPB) 230 can also be configured to store one or more non-filtered reconstructed blocks 215 or generally non-filtered reconstructed samples if, for example, the reconstructed blocks 215 are not filtered by the loop filter unit 220, or to store any other further processed version of the reconstructed blocks or samples.

[0123] Mode Selection (Partitioning & Prediction) The mode selection unit 260 includes a classification unit 262, an inter prediction unit 244, and an intra prediction unit 254, and is configured to receive or obtain original picture data, for example, the original block 203 (the current block 203 of the current picture 17), and reconstructed picture data, for example, from the same (current) picture and / or from one or more already decoded pictures from, for example, the decoded picture buffer 230 or other buffers (for example, a line buffer not shown), filtered and / or unfiltered reconstructed samples or blocks. The reconstructed picture data is used as reference picture data for prediction, for example, inter prediction or intra prediction, to obtain the prediction block 265 or predictor 265.

[0124] The mode selection unit 260 may be configured to determine or select a classification and a prediction mode (for example, an intra or inter prediction mode) for the prediction mode of the current block (without classification) and generate a corresponding prediction block 265 used for the calculation of the residual block 205 and the reconstruction of the reconstructed block 215.

[0125] Embodiments of the mode selection unit 260 may be configured to select a partitioning and prediction mode that provides the best match, or in other words, the minimum residual (the minimum residual implies better compression for transmission or storage) or the minimum signaling overhead (the minimum signaling overhead implies better compression for transmission or storage), or takes both into account or strikes a balance, from, for example, the partitioning and prediction modes supported by the mode selection unit 260 or available to the mode selection unit 260. The mode selection unit 260 may be configured to determine the partitioning and prediction modes based on rate-distortion optimization (RDO), i.e., to select the prediction mode that provides the minimum rate distortion. Terms such as "best," "minimum," "optimal," etc. in this context do not necessarily refer to the overall "best," "minimum," "optimal," etc., but may also refer to a termination or selection criterion such as a value exceeding or falling below a threshold, or potentially leading to a "quasi-optimal selection" while satisfying other constraints that reduce complexity and processing time.

[0126] In other words, the partitioning unit 262 may be configured to iteratively use, for example, quadtree partitioning (QT), binary partitioning (BT), or ternary tree partitioning (TT), or any combination thereof, to partition block 203 into smaller block partitions or sub-blocks (which also form blocks), and for example, perform prediction for each of the block partitions or sub-blocks. Mode selection may include the selection of the tree structure of the partitioned block 203, and the prediction mode is applied to each of the block partitions or sub-blocks.

[0127] The partitioning and prediction processing (e.g., by the partitioning unit 260) and prediction processing (by the inter prediction unit 244 and the intra prediction unit 254) performed by the exemplary video encoder 20 are described in more detail below.

[0128] Partitioning The partitioning unit 262 can partition (or divide) the current block 203 into smaller partitions, for example, smaller blocks of square or rectangular size. These smaller blocks (which may also be referred to as sub-blocks) can be further partitioned into even smaller partitions. This is also called tree partitioning or hierarchical tree partitioning. For example, a root block at root tree level 0 (hierarchical level 0, depth 0) can be recursively partitioned, for example, into two or more blocks at the next lower tree level, for example, nodes at tree level 1 (hierarchical level 1, depth 1), and these blocks can be further partitioned into two or more blocks at the next lower level, for example, at tree level 2 (hierarchical level 2, depth 2), and so on until the partitioning is terminated, for example, when an end criterion is met, for example, the maximum tree depth or the minimum block size is reached. Blocks that are not further partitioned are also called leaf blocks or leaf nodes of the tree. A tree using partitioning into two partitions is called a binary tree (BT), a tree using partitioning into three partitions is called a ternary tree (TT), and a tree using partitioning into four partitions is called a quadtree (QT).

[0129] As described above, the term "block" as used herein can be a portion of a picture, particularly a portion of a square or rectangle. For example, in relation to HEVC and VVC, a block can be a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), and a transform unit (TU), and / or a corresponding block, for example, a coding tree block (CTB), a coding block (CB), a transform block (TB), or a prediction block (PB), or can correspond to them.

[0130] For example, a coding tree unit (CTU) can be or include the CTB of luma samples, two corresponding CTBs of chroma samples of a picture having three sample arrays, or the CTB of samples of a picture coded using three separate colour planes and syntax structures for coding monochrome pictures or samples. Correspondingly, a coding tree block (CTB) can be an NxN block of samples for some value of N such that the splitting of the component CTB is a partition. A coding unit (CU) can be or include the coding block of luma samples, two corresponding coding blocks of chroma samples of a picture having three sample arrays, or the coding block of samples of a picture coded using three separate colour planes and syntax structures for coding monochrome pictures or samples. Correspondingly, a coding block (CB) can be an MxN block of samples for some values of M and N such that the splitting of the CTB into coding blocks is a partition.

[0131] For example, in an embodiment according to HEVC, a coding tree unit (CTU) can be split into CUs by using a quadtree structure represented as a coding tree. The determination of whether to code a picture area using inter-picture (temporal) prediction or to code a picture area using intra-picture (spatial) prediction is made at the CU level. Each CU can be further split into one, two, or four PUs according to the PU split type. Within one PU, the same prediction process is applied and the relevant information is sent to the decoder based on the PU. After obtaining the residual block by applying the prediction process based on the PU split type, the CU can be partitioned into transform units (TUs) by another quadtree structure similar to the coding tree for the CU.

[0132] For example, in embodiments according to the currently developed latest video coding standard called Versatile Video Coding (VVC), quadtree and binary tree (QTBT) partitioning is used to partition coding blocks. In the QTBT block structure, a coding unit (CU) can have a shape that is either square or rectangular. For example, a coding tree unit (CTU) is first partitioned by a quadtree structure. The leaf nodes of the quadtree are further partitioned by a binary tree or a ternary (or triple) tree structure. The leaf nodes of the partitioning tree are called coding units (CUs), and their segmentation is used for prediction and transformation processing without any further partitioning. This means that the CUs, prediction units (PUs), and transform units (TUs) have the same block size in the QTBT coding block structure. In parallel, multi-partitioning, for example, ternary tree partitioning, has been proposed to be used together with the QTBT block structure.

[0133] In one example, the mode selection unit 260 of the video encoder 20 can be configured to perform any combination of the partitioning techniques described herein.

[0134] As described above, the video encoder 20 is configured to determine or select the best or optimal prediction mode from a set of (predetermined) prediction modes. The set of prediction modes can include, for example, an intra prediction mode and / or an inter prediction mode.

[0135] Intra Prediction A set of intra prediction modes can include, for example, 35 different intra prediction modes defined in HEVC, such as non-directional modes like DC (or average) mode and planar mode, or directional modes, or alternatively, 67 different intra prediction modes defined for VVC, such as non-directional modes like DC (or average) mode and planar mode, or directional modes.

[0136] The intra prediction unit 254 is configured to generate an intra prediction block 265 using the reconstructed samples of neighboring blocks of the same current picture according to an intra prediction mode among a set of intra prediction modes.

[0137] The intra prediction unit 254 (or generally the mode selection unit 260) is further configured to output an intra prediction parameter (or generally information indicating the selected intra prediction mode for a block) to the entropy encoding unit 270 in the form of a syntax element 266 so that, for example, the video decoder 30 can receive the prediction parameter and use it for decoding and include it in the encoded picture data 21.

[0138] Inter prediction A set of (or possible) inter prediction modes depends on available reference pictures (i.e., for example, at least previously partially decoded pictures stored in the DBP 230) and other inter prediction parameters, for example, whether the entire reference picture is used to search for the best matching reference block or only a part of the reference picture, for example, only the search window area around the area of the current block, and / or for example, whether pixel interpolation, for example, half / semi-pel and / or quarter-pel interpolation, is applied.

[0139] In addition to the above prediction modes, a skip mode and / or a direct mode may be applied.

[0140] The inter prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (neither shown in FIG. 2). The motion estimation unit is configured to receive or obtain, for motion estimation, the picture block 203 (the current picture block 203 of the current picture 17) and the decoded picture 231, or at least one or a plurality of already reconstructed blocks, for example, the reconstructed blocks of one or a plurality of other / different already decoded pictures 231. For example, the video sequence may include the current picture and the already decoded picture 231, or in other words, the current picture and the already decoded picture 231 may be part of or form a sequence of pictures forming the video sequence.

[0141] The encoder 20 may be configured to select, for example, a reference block from a plurality of reference blocks of the same or different pictures among a plurality of other pictures, and provide an offset (spatial offset) between the reference picture (or reference picture index) and / or the position (x, y coordinates) of the reference block and the position of the current block to the motion estimation unit as an inter prediction parameter. This offset is also called a motion vector (MV).

[0142] The motion compensation unit is configured to obtain, for example, receive, inter-prediction parameters and perform inter-prediction based on or using the inter-prediction parameters to obtain an inter-prediction block 265. The motion compensation performed by the motion compensation unit may include fetching or generating a prediction block based on a motion / block vector determined, perhaps, by motion estimation that performs interpolation with sub-pixel accuracy. Interpolation filtering can generate additional pixel samples from known pixel samples and thus potentially increase the number of candidate prediction blocks that can be used to code a picture block. As will be described in more detail below, interpolation filtering can be performed using one or more alternative interpolation filters depending on the accuracy of the motion vector. Upon receiving a motion vector for a PU of the current picture block, the motion compensation unit may find a prediction block pointed to by the motion vector in one of the reference picture lists.

[0143] The motion compensation unit may also generate blocks for use by the video decoder 30 when decoding a picture block of a video slice and syntax elements associated with the video slice.

[0144] Entropy coding The entropy encoding unit 270 is configured to apply, for example, an entropy encoding algorithm or method (e.g., variable length coding (VLC) method, context adaptive VLC (CAVLC), arithmetic coding method, binarization, context adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or another entropy encoding method or technique) or bypass (non-compression) to the quantized coefficients 209, inter-prediction parameters, intra-prediction parameters, loop filter parameters, and / or other syntax elements, so as to obtain, for example, encoded picture data 21 that can be output via output 272 in the form of an encoded bitstream 21 such that the video decoder 30 can receive the parameters and use them for decoding. The encoded bitstream 21 can be transmitted to the video decoder 30 or stored in a memory for later transmission or retrieval by the video decoder 30.

[0145] Variations in the structure of the video encoder 20 and others can be used to encode the video stream. For example, a non-transform-based encoder 20 can directly quantize the residual signal without the transform processing unit 206 for a particular block or frame. In another implementation, the encoder 20 can have a quantization unit 208 and an inverse quantization unit 210 combined in a single unit.

[0146] Decoder and Decoding Method Figure 3 shows an example of a video decoder 30 configured to implement the technology of the present application. The video decoder 30 is configured to receive, for example, encoded picture data 21 (e.g., an encoded bitstream 21) encoded by an encoder 20 in order to obtain a decoded picture 331. The encoded picture data or bitstream includes information for decoding data representing an encoded picture, for example, a picture block of an encoded video slice and associated syntax elements.

[0147] In the example of Figure 3, the decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g., an adder 314), a loop filter 320, a decoded picture buffer (DBP) 330, an inter prediction unit 344, and an intra prediction unit 354. The inter prediction unit 344 may be or include a motion compensation unit. The video decoder 30 may perform a decoding path that is generally inverse to the encoding path described in relation to the video encoder 100 of Figure 2 in some examples.

[0148] As described in relation to the encoder 20, 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 344, and the intra prediction unit 354 are also considered to form the "built-in decoder" of the video encoder 20. Therefore, the inverse quantization unit 310 can be functionally identical to the inverse quantization unit 110, the inverse transform processing unit 312 can be functionally identical to the inverse transform processing unit 212, the reconstruction unit 314 can be functionally identical to the reconstruction unit 214, the loop filter 320 can be functionally identical to the loop filter 220, and the decoded picture buffer 330 can be functionally identical to the decoded picture buffer 230. Therefore, the descriptions given for each unit and function of the video 20 encoder are applied mutatis mutandis to each unit and function of the video decoder 30.

[0149] Entropy decoding The entropy decoding unit 304 analyzes the bitstream 21 (or generally the encoded picture data 21), for example, performs entropy decoding on the encoded picture data 21 to obtain, for example, the quantized coefficients 309 and / or the decoded coding parameters (not shown in FIG. 3), such as 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 any or all of other syntax elements. The entropy decoding unit 304 may be configured to apply a decoding algorithm or method corresponding to the encoding method described in relation to the entropy encoding unit 270 of the encoder 20. The entropy decoding unit 304 may be further configured to provide inter prediction parameters, intra prediction parameters, and / or other syntax elements to the mode selection unit 360 and provide other parameters to other units of the decoder 30. The video decoder 30 may receive syntax elements at the level of the video slice and / or at the level of the video block.

[0150] Inverse quantization The inverse quantization unit 310 receives the quantization parameter (QP) (or generally information related to inverse quantization) and the quantized coefficients from the encoded picture data 21 (e.g., by the entropy decoding unit 304, for example, by analyzing and / or decoding), and applies inverse quantization based on the quantization parameter to the decoded quantized coefficients 309 to obtain the dequantized coefficients 311, which may also be referred to as transform coefficients 311. The inverse quantization process may include using the quantization parameter determined by the video encoder 20 for each video block within the video slice to determine the degree of quantization and, similarly, the degree of inverse quantization to be applied.

[0151] Inverse transform The inverse transformation processing unit 312 may be configured to apply a transformation to the dequantized coefficient 311, also referred to as the transformation coefficient 311, in order to obtain the residual block 213 reconstructed in the sample region. The reconstructed residual block 213 may also be referred to as the transformation block 313. The transformation may be an inverse transformation, such as an inverse DCT, inverse DST, inverse integer transformation, or a conceptually similar inverse transformation process. The inverse transformation processing unit 312 may be further configured to receive transformation parameters or corresponding information from the encoded picture data 21 (e.g., by parsing and / or decoding by the entropy decoding unit 304, for example) in order to determine the transformation applied to the dequantized coefficient 311.

[0152] Reconstruction The reconstruction unit 314 (e.g., an adder or accumulator 314) may be configured to add the reconstructed residual block 313 to the prediction block 365 in the sample region, for example, by adding the sample values of the reconstructed residual block 313 and the sample values of the prediction block 365 to obtain the reconstructed block 315 in the sample region.

[0153] Filtering (Either within or after the coding loop) The loop filter unit 320 is configured to filter the reconstructed block 315 to obtain a filtered block 321, for example, to smooth pixel transitions or otherwise improve the quality of the video. The loop filter unit 320 may include a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, such as a bilateral filter, an adaptive loop filter (ALF), sharpening, a smoothing filter, or a joint filter, or any combination thereof. The loop filter unit 320 is shown as an in-loop filter in FIG. 3, but in other configurations, the loop filter unit 320 may be implemented as a post-loop filter.

[0154] Decoded picture buffer Then, the decoded video block 321 of the picture is stored in the decoded picture buffer 330 that stores the decoded picture 331 for subsequent motion compensation with respect to other pictures and / or for outputting respectively on a display as a reference picture.

[0155] The decoder 30 is configured to output the decoded picture 311, for example, via the output 312, for presentation or viewing by the user.

[0156] Prediction The inter prediction unit 344 can be identical to the inter prediction unit 244 (particularly the motion compensation unit), and the intra prediction unit 354 can be functionally identical to the inter prediction unit 254. It performs determination and prediction of splitting or segmentation based on the segmentation and / or prediction parameters or respective information received from the encoded picture data 21 (for example, by the entropy decoding unit 304 through analysis and / or decoding). The mode selection unit 360 can be configured to perform prediction (intra or inter prediction) for each block based on the reconstructed picture, block, or respective samples (filtered or unfiltered) to obtain the prediction block 365.

[0157] When the video slice is coded as an intra-coded (I) slice, the intra prediction unit 354 of the mode selection unit 360 is configured to generate a prediction block 365 for the picture block of the current video slice based on the signaled intra prediction mode and data from the already decoded blocks of the current picture. When the video picture is coded as an inter-coded (i.e., B or P) slice, the inter prediction unit 344 (e.g., the motion compensation unit) of the mode selection unit 360 is configured to generate a prediction block 365 for the video block of the current video slice based on the motion vector and other syntax elements received from the entropy decoding unit 304. Regarding inter prediction, the prediction block can be generated from one of the reference pictures in one of the reference picture lists. The video decoder 30 can construct the reference frame lists, List 0 and List 1, using a default construction technique based on the reference pictures stored in the DPB 330.

[0158] The mode selection unit 360 is configured to determine prediction information about video blocks of the current video slice by analyzing motion vectors and other syntax elements, and to generate a prediction block for the current decoded video block using the prediction information. For example, the mode selection unit 360 uses a part of the received syntax elements to determine the prediction mode (e.g., intra or inter prediction) used to code the video blocks of the video slice, the slice type of the inter prediction (e.g., B slice, P slice, or GPB slice), the construction information regarding one or more of the reference picture lists for the slice, the motion vectors for each inter-coded video block of the slice, the inter prediction status for each inter-coded video block of the slice, and other information for decoding the video blocks within the current video slice.

[0159] Other variations of the video decoder 30 may be used to decode the encoded picture data 21. For example, the decoder 30 may generate an output video stream without the loop filtering unit 320. For example, a decoder 30 that does not rely on transformation may directly inverse quantize the residual signal without the inverse transform processing unit 312 for a particular block or frame. In another implementation, the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined in a single unit.

[0160] It should be understood that in the encoder 20 and the decoder 30, the processing result of the current step may be further processed and then output to the next step. For example, after interpolation filtering, motion vector derivation, or loop filtering, further operations such as Clip or Shift may be performed on the processing results of interpolation filtering, motion vector derivation, or loop filtering.

[0161] Note that further operations may be applied to the derived motion vectors of the current block (including, but not limited to, affine mode control point motion vectors, affine, plane, sub-block motion vectors in the ATMVP mode, temporal motion vectors, etc.). For example, the value of the motion vector is constrained to a predetermined range according to its representation bits. When the representation bits of the motion vector are bitDepth, the range is -2^(bitDepth-1) to 2^(bitDepth-1)-1, where "^" means exponentiation. For example, when bitDepth is set to be equal to 16, the range is -32768 to 32767, and when bitDepth is set to be equal to 18, the range is -131072 to 131071.

[0162] 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 herein. In an embodiment, the video coding device 400 may be a decoder such as the video decoder 30 of FIG. 1A or an encoder such as the video encoder 20 of FIG. 1A.

[0163] The video coding device 400 includes an incoming port 410 (or input port 410) and a receiver unit (Rx) 420 for receiving data, a processor, logic unit, or central processing unit (CPU) 430 for processing data, a transmitter unit (Tx) 440 and an outgoing port 450 (or output port 450) for transmitting data, and a memory 460 for storing data. The video coding device 400 may also include optical - electrical (OE) components and electrical - optical (EO) components coupled to the incoming port 410, the receiver unit 420, the transmitter unit 440, and the outgoing port 450 for the transmission or reception of optical or electrical signals.

[0164] Processor 430 is implemented by hardware and software. Processor 430 can be implemented as one or more CPU chips, cores (e.g., as a multi-core processor), FPGA, ASIC, and DSP. Processor 430 communicates with incoming port 410, receiver unit 420, transmitter unit 440, outgoing port 450, and memory 460. Processor 430 includes coding module 470. Coding module 470 implements the disclosed embodiments described above. For example, coding module 470 implements, processes, prepares, or provides various coding operations. Thus, including coding module 470 significantly improves the functionality of video coding device 400 and results in the conversion of video coding device 400 to different states. Alternatively, coding module 470 is implemented as instructions stored in memory 460 and executed by processor 430.

[0165] Memory 460 can include one or more disks, tape drives, and solid state drives, and can be used as an over-flow data storage device for storing such programs when selected for program execution and for storing instructions and data read during program execution. Memory 460 can be, for example, volatile and / or non-volatile, and can be read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and / or static random access memory (SRAM).

[0166] FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and the destination device 14 of FIG. 1 according to an exemplary embodiment.

[0167] The processor 502 of the device 500 can be a central processing unit. Alternatively, the processor 502 can be any other type of one or more devices, existing or to be developed in the future, that can manipulate or process information. The disclosed implementation can be carried out by a single processor, such as the processor 502 as shown, but advantages in terms of speed and efficiency can be achieved by using two or more processors.

[0168] The memory 504 of the device 500 can be a read-only memory (ROM) device or a random access memory (RAM) device in the 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 are accessed by the processor 502 using the bus 512. The memory 504 can further include an operating system 508 and an application program 510, and the application program 510 includes at least one program that enables the processor 502 to execute the methods described herein. For example, the application program 510 can include applications 1 through N that further include a video coding application that executes the methods described herein.

[0169] The device 500 can also include one or more output devices, such as a display 518. The display 518 can be, in one example, a touch display that is combined with a touch sensing element operable to sense touch input to the display. The display 518 can be coupled to the processor 502 via the bus 512.

[0170] Although shown here as a single bus, the bus 512 of the apparatus 500 may be composed of a plurality of buses. Further, the secondary storage 514 can be directly coupled to other components of the apparatus 500 or can be accessed via a network, and can include a single integrated unit such as a memory card or a plurality of units such as a plurality of memory cards. Therefore, the apparatus 500 can be implemented in a wide variety of configurations.

[0171] Hereinafter, the concepts presented in this specification will be described in more detail.

[0172] Prediction of Motion Vectors In the current VVC design, spatial motion vector prediction is used. Spatial motion vector prediction means that during inter prediction, the motion information of spatially neighboring blocks is used to predict the motion vector of the current inter block. In particular, in the merge and skip modes, the motion vectors from the adjacent spatially neighboring blocks of the current block are used. In the merge and skip modes, so-called HMVP candidates can be used. The HMVP candidates include motion information from spatially neighboring blocks based on history. "Based on history" means that the motion information from blocks before the current block in decoding order is used. Such preceding blocks are from the same frame as the current block and are in some spatial neighborhood around the current block, but are not necessarily adjacent blocks like normal spatial merge candidates.

[0173] Construction of Merge Candidate List The merge candidate list is constructed based on the following candidates. · Up to four spatial merge candidates derived from five spatially neighboring blocks as shown in FIG. 6, · One temporal merge candidate derived from two temporally co-located blocks, ·Additional merge candidates including combined dual prediction candidates and zero motion vector candidates. The construction of the merge candidate list is described in more detail below by referring to FIG. 12.

[0174] Spatial candidates The first set of candidates in the merge candidate list are spatially neighboring blocks as shown in FIG. 6. For the merge of blocks for inter prediction, up to four candidates are inserted into the merge list by examining A1, B1, B0, A0, and B2 in this order. Instead of simply checking whether neighboring blocks are available and contain motion information, additional redundancy checks are performed before considering all motion data of neighboring blocks as merge candidates. These redundancy checks can be divided into two categories for the following two different purposes. ·Avoid having candidates with redundant motion data in the HMI list, ·Prevent merging two partitions that can be represented by other means and generate redundant syntax.

[0175] History-based motion vector prediction For further improvement of motion vector prediction, techniques have been proposed that use motion information from non-adjacent CUs (the motion information includes one reference picture index / multiple reference picture indexes and one motion vector / multiple motion vectors). One such technique is history-based motion vector prediction (HMVP). HMVP uses a look-up table (LUT) that contains motion information from already coded CUs. Basically, the HMVP method consists of the following two main parts. 1. The HMVP LUT construction and update method shown in FIGS. 10 and 11, 2. The use of the HMVP LUT to construct a merge candidate list (or AMVP candidate list) shown in FIG. 12.

[0176] HMVP LUT construction and update method The LUT is maintained during the encoding and / or decoding process. When reaching a new slice, the LUT is emptied. Whenever the current CU is inter-coded, the related motion information is always added as a new HMVP candidate to the last entry of the table. The size of the LUT (denoted as N) is a parameter of the HMVP method. If the number of HMVP candidates from an already coded CU is more than the size of this LUT, the table update method is applied, and thus, this LUT always contains no more than N already coded motion candidates. Two table update methods are proposed. 1. The First-In-First-Out (FIFO) LUT update method shown in FIG. 10, 2. The Constrained FIFO LUT update method shown in FIG. 11.

[0177] FIFO LUT update method According to the FIFO LUT update method, before inserting a new candidate, the oldest candidate (the 0th table entry) is deleted from the table. This process is shown in FIG. 10. In this figure, H0 is the oldest (0th) HMVP candidate and X is the new candidate.

[0178] This update method is relatively less complex, but when this method is applied, some of the elements of the LUT may become the same (may contain the same motion information). Thus, the data in the LUT may become redundant, and the diversity of the motion information in the LUT is inferior to the method where duplicate candidates are deleted.

[0179] Constrained FIFO LUT update method To further improve the coding efficiency, the Constrained FIFO LUT update method is introduced. According to this method, a redundancy check is applied before inserting a new HMVP candidate into the table. The redundancy check means knowing whether the motion information from the new candidate X matches the motion information contained in an existing candidate H m in the LUT. Such a candidate H mIf not found, a simple FIFO method is used; otherwise, the following procedure is executed. 1. H m All entries of the LUT after H are shifted one position to the left (towards the beginning of the table), as a result, candidate H m is deleted from the table, and one position at the end of the LUT is freed. 2. New candidate X is added to the first empty position in the table.

[0180] An example of the use of the constrained FIFO LUT update method is shown in FIG. 11.

[0181] Use of the HMVP LUT for motion vector coding HMVP candidates can be used in the merge candidate list construction process and / or the AMVP candidate list construction process.

[0182] Use of the HMVP LUT in the construction of the merge candidate list In some examples, HMVP candidates are inserted into the merge list from the last entry to the first entry (e.g., H N-1 、H N-2 、...、H0) after the temporal merge candidates. The traversal order of the LUT is shown in FIG. 12. If an HMVP candidate is equal to one of the candidates already given in the merge list, such an HMVP candidate is not added to the HMVP list. Due to the limited size of the merge list, some HMVP candidates, especially those at the beginning of the LUT, may not be used in the merge list construction process for the current CU.

[0183] Use of the HMVP LUT in the AMVP candidate list construction process The HMVP LUT constructed for merge mode can also be used for AMVP. The difference is that only some entries from this LUT are used for the construction of the AMVP candidate list. More specifically, only the last M entries of the HMVP LUT are used (for example, M is equal to 4). During the AMVP candidate list construction process, the HMVP candidates are from the last (N - K)th entry to the second last entry after the TMVP candidates, that is, H N-1 , H N-2 ,..., H N-K are inserted into the AMVP candidate list. The traversal order of the LUT is shown in FIG. 12.

[0184] Only HMVP candidates having the same reference picture as the target reference picture of AMVP are used. If an HMVP candidate is equal to one of the candidates already given in the HMI list, this HMVP candidate is not used for the construction of the AMVP candidate list. Due to the limited size of the AMVP candidate list, some HMVP candidates may not be used in the AMVP list construction process for the current CU.

[0185] Switchable interpolation filter The difference in motion vectors of inter-predicted blocks by translational motion can be coded with three different precisions (i.e., quarter pel, full pel, and 4 pels). The interpolation filter (IF) used for each fractional position is determined. In the present disclosure, a switchable interpolation filter (SIF) technique enables the use of one or two alternative luma interpolation filters for the half pel position. The switching between available luma interpolation filters can be done at the CU level. To reduce the signaling overhead, the switching depends on the precision of the motion vectors used. For that purpose, the Adaptive Motion Vector Resolution (AMVR) scheme is extended to support the precision of half pel luma motion vectors as well. Only in the case of this half pel motion vector precision mode, an alternative half pel interpolation filter can be used, and the alternative half pel interpolation filter is indicated by an additional syntax element indicating which interpolation filter is used. In the skip or merge mode using spatial merge candidates, the value of this syntax element can be inherited from neighboring blocks.

[0186] Half pel AMVR mode A further AMVR mode for non-affine non-merge inter-coded CUs that enables signaling of the difference in motion vectors with half pel precision is introduced. The existing AMVR scheme of the current VVC draft is extended as follows. When amvr_flag == 1, immediately after the syntax element amvr_flag, there is a newly context-modeled binary syntax element hpel_amvr_flag, and this hpel_amvr_flag indicates the use of the new half pel AMVR mode when hpel_amvr_flag == 1. Otherwise, i.e., when hpel_amvr_flag == 0, the selection between the full pel and 4 pel AMVR modes is indicated by the syntax element amvr_precision_flag as in the current VVC draft.

[0187] Alternative luma half - pel interpolation filter For non - affine non - merge inter - coded CUs that use half - pel motion vector precision (i.e., half - pel AMVR mode), the switching between the HEVC / VVC half - pel luma interpolation filter and one or more alternative half - pel interpolations can be done based on the value of the new syntax element if_idx (interpolation filter index). The syntax element if_idx is signaled only in the case of half - pel AMVR mode. In the skip / merge mode that uses spatial merge candidates, the value of the interpolation filter index is inherited from neighboring blocks.

[0188] It can be understood that the fractional position of the motion vector can be represented, for example, by the luma position (xFracL, yFracL) in units of fractional samples. The motion vector of the selected merge candidate can be represented by refMvLX

[0000] and refMvLX

[0001] , and mvLX = mvL0 or mvL1.

[0189] In the example xFrac L = refMvLX

[0000] & 15 (8 - 738) yFrac L = refMvLX

[0001] & 15 (8 - 739) That is.

[0190] xFrac L (or yFrac L ) is equal to 0 (i.e., the MV points to an integer position), interpolation is not used. Otherwise (xFrac L is in the range of [1, 15]), the interpolation filter with the coefficient specified in f L [ xFrac L is used. The luma interpolation filter coefficients f L [ p ] for each fractional sample position p (p is in the range of [1, 15]) are defined in Table 8 - 8 (Table 1).

[0191] This Table 8-8 (Table 1) is an example of a set of interpolation filters, and one interpolation filter is selected according to the fractional position. One interpolation filter (interpolation filter coefficient) can be one line of Table 8-8 (Table 1). In the example, the set of interpolation filters of the present disclosure can have the same interpolation filter for all positions except the half-sample position (fractional position: 1 / 2).

[0192] The following Table 8-8 (Table 1) shows the HEVC / VVC interpolation filter coefficients f L [ p ] for each fractional sample position p (p is in the range of [1, 15] and the precision is 1 / 16 per (pixel)). In this table, when p = 8, the interpolation filter coefficient f L [ p ] is the half-pel interpolation filter coefficient. As discussed above, in order to enable switching between these half-pel interpolation filters, additional interpolation filters can be added as an alternative to this half-pel interpolation filter. Some examples of alternative half-pel interpolation filters are shown below.

[0193]

Table 1

[0194] Implementation using one alternative 6-tap half-pel interpolation filter In the example, a 6-tap interpolation filter can be used as an alternative to the normal HEVC / VVC half-pel interpolation filter shown in Table 8-8 (Table 1). The following Table 1 (Table 2) shows the mapping between the value of the syntax element if_idx (or the derived IF index) and the selected half-pel luma interpolation filter.

[0195]

Table 2

[0196] Implementation using two alternative 8-tap half-pel interpolation filters In another example, two 8-tap interpolation filters may be used as an alternative to the normal HEVC / VVC half-pel interpolation filter shown in Table 8-8 (Table 1). Table 2 (Table 3) below shows the mapping between the value of the syntax element if_idx and the selected half-pel luma interpolation filter.

[0197] [Table 3]

[0198] Implementation using two alternative 6-tap half-pel interpolation filters In another example, two 6-tap interpolation filters may be used as an alternative to the normal HEVC / VVC half-pel interpolation filter shown in Table 8-8 (Table 1). Table 3 (Table 4) below shows the mapping between the value of the syntax element if_idx and the selected half-pel luma interpolation filter.

[0199] [Table 4]

[0200] As shown in Table 4 (Table 5) of the interpolation filter, the interpolation filter for the half-pel position (see line "8" of this Table 4 (Table 5)) can be switched in the present disclosure. In the present disclosure, when the corresponding MV points to a half-sample position, an alternative or switchable half-sample interpolation filter is used to interpolate the value of the half-sample.

[0201] [Table 5]

[0202] More specifically, the following aspects are described. 1. Modification of the method for constructing / updating the motion information candidate list based on history (i.e., the HMI list). In addition to the motion information of one or more coded / decoded blocks preceding the block, the interpolation filter (IF) index of the preceding block (e.g., the half-pel interpolation filter index (hpelIfIdx)) is stored in the HMI list. In particular, the IF index is also stored in the HMI candidate or record of the HMI list. In this way, the IF index can be propagated through the HMI list, achieving coding consistency and higher coding efficiency. 2. Derivation procedure of the interpolation filter index (half-pel interpolation filter index) for the merge mode. When the block has a merge candidate index corresponding to a history-based candidate, the IF index (half-pel interpolation filter index) of this history-based candidate is used for the current block. 3. Propagation of the SIF index across the CTU boundary. Based on the current SIF design, when the SIF technology is applied in the mode of inheriting motion information from the upper spatial neighboring blocks, if the current block is at the upper boundary of the CTU, the line memory is increased. In the description presented herein, the position of the current block is examined. When the current block is at the upper boundary of the CTU and inheriting motion information from the neighboring blocks of the upper left (B0), upper (B1), and upper right (B2), the IF index is not inherited, and instead, a default value is used to reduce the cost of the line memory.

[0203] An example of the propagation of the SIF index across the CTU boundary is shown in FIG. 7. In this example, the motion information is inherited from neighboring blocks of B1 (upper) that belong to a CTU different from the CTU containing the current block 700. In this case, the SIF index of the blocks of B1 has to be stored in the line buffer in the prior art. The present invention prevents the propagation of the SIF index in such cases and thus reduces the requirements for the line buffer size. During the construction of the merge list, the position of the current block is examined. As shown in FIG. 7, when the current block is at the upper boundary of the CTU, the IF index is not inherited and a default value is used to reduce the cost of the line memory while inheriting the motion information from the neighboring blocks of the upper left (B0), upper (B1), and upper right (B2). Details are described below with reference to FIGS. 8 and 9.

[0204] FIG. 13A shows a flowchart of a construction method 1300 for a history-based motion information candidate list (i.e., HMI list), and the method includes the following steps. In step 1301, a history-based motion information candidate list is obtained, and the HMI list is an ordered list of N history-based motion information candidates H related to the motion information of N preceding blocks preceding the block (including their motion information), where k = 0,..., N - 1, N is an integer greater than 0, and each history-based motion information candidate includes the following elements. k In step 1303, the HMI list is updated based on the motion information of the block, and the motion information of the block includes the following elements. i) One or more motion vectors MV of the preceding block, ii) One or more reference picture indices corresponding to the MV of the preceding block, and iii) The interpolation filter index of the preceding block. In step 1303, the HMI list is updated based on the motion information of the block, and the motion information of the block includes the following elements. i) One or more motion vectors MV of the block, ii) One or more reference picture indices corresponding to the MV of the block, and iii) Block interpolation filter index.

[0205] It may be noted that one or more MVs of a block point to MVs corresponding to the L0 and L1 reference picture lists. The same applies to the reference picture index.

[0206] As shown in FIG. 13B, step 1301 can be step 1311 including loading a history-based motion information candidate list (HMI table), and step 1303 can be step 1313 including updating a history-based motion information candidate list (table) using the motion information of the decoded block. The HMI table with multiple HMVP candidates is maintained during the encoding / decoding process. The table is emptied when reaching a new slice. When there are inter-coded blocks in a slice, the blocks are decoded based on a motion information candidate list including history-based motion information candidates (step 1302), and the related motion information of the blocks is added to the last entry of the table as new HMVP candidates (step 1303).

[0207] FIG. 14 shows a flowchart of a method for inter prediction for blocks within a frame of a video signal, the method including the following steps. In step 1401, a history-based motion information candidate list (i.e., HMVP list) is constructed, and the HMI list is an ordered list of N history-based motion information candidates H related to the motion information of a plurality of blocks preceding the block, where k = 0,..., N - 1, N is an integer greater than 0, and each history-based motion information candidate includes the following elements. k wherein each history-based motion information candidate includes the following elements. i) One or more motion vectors MV, ii) One or more reference picture indices corresponding to the MV, and iii) Interpolation filter index. In step 1402, add movement information candidates based on one or more histories from the HMI list to the movement information candidate list for the block. In step 1403, derive movement information for the block based on the movement information candidate list.

[0208] It can be understood that the movement information candidate list refers to the merge candidate list as follows.

[0209] It can be understood that the merge candidates based on the history are included in the movement information candidate list in step 1403.

[0210] FIG. 15 shows a flowchart of a method for constructing and updating a movement information candidate list (i.e., HMI list) based on history. In step 1501, the HMI list is constructed. In step 1502, at least one of elements i) and ii) of the movement information candidate based on each history of the HMVP list is compared with the corresponding element of the current block. Step 1502 includes comparing whether the movement vector of the movement information candidate based on the history in the movement information candidate list based on the history is the same as the corresponding movement vector of the block, and comparing whether the reference picture index of the movement information candidate based on the history is the same as the corresponding reference picture index of the block. In an alternative design, step 1502 includes comparing whether at least one of the movement vectors of the movement information candidates based on each history is different from the corresponding movement vector of the block, and comparing whether at least one of the reference picture indexes of each HMVP candidate is different from the corresponding reference picture index of the block. The result of the comparison based on the elements is referred to as the comparison result in FIG. 15.

[0211] If the comparison result is such that at least one of the following elements i) and ii) of the history-based motion information candidate of the history-based motion information candidate list is different from the corresponding element of the block motion information, the current block motion information is added to the last position of the HMVP list (step 1503). Otherwise, if the following elements i) and ii) of the history-based motion information candidate of the history-based motion information candidate list are the same as the corresponding elements of the block motion information, the history-based motion information candidate is deleted from the history-based motion information candidate list, and a history-based motion information candidate H including the block motion information is added to the last position of the history-based motion information candidate list, and k = N - 1 (step 1504). k is added, where k = N - 1 (step 1504).

[0212] And the above comparison is performed only to examine the differences regarding the MV and the reference picture index without comparing the IF index.

[0213] Further embodiments are summarized in the following aspects.

[0214] A method for deriving an interpolation filter index (or an index of a set of interpolation filters) for a current block according to a first aspect of the present invention, comprising: constructing a history-based motion information list (HMIL or HMVP table), which is an ordered list of N motion records H related to N previous blocks of a frame, where k = 0,..., N - 1, N is 1 or more, and each motion record includes one or more motion vectors, one or more reference picture indices corresponding to one or more motion vectors, and an interpolation filter index (or an index of a set of interpolation filters) corresponding to one or more motion vectors (such as the same filter index or the same set of filters for both of two MVs); k step, and A method including the step of determining history-based motion information candidates (such as HMVP candidates) for the current block based on a history-based motion information list (such as determining HMVP candidates for the current block from an HMVP list or an HMVP table).

[0215] In a possible implementation form of the device according to the first aspect itself, here, the step of determining history-based motion information candidates for the current block based on a history-based motion information list is Deriving or inferring or determining the interpolation filter index (or index of a set of interpolation filters) of record Hk as the interpolation filter index (or index of a set of interpolation filters) for the current block, wherein the determined or selected history-based motion information candidates (such as HMVP candidates) correspond to record Hk, including deriving or inferring or determining.

[0216] In any of the above implementations of the first aspect or in a possible implementation form of the device according to the first aspect itself, here, the motion records in the history-based motion information list are ordered in the order in which the motion records of the previous blocks are obtained from the bitstream.

[0217] In any of the above implementations of the first aspect or in a possible implementation form of the device according to the first aspect itself, the history-based motion information list has a length of N, and N is 5.

[0218] In any of the above implementations of the first aspect or in a possible implementation form of the device according to the first aspect itself, the step of constructing a history-based motion information list (HMVL) is Before adding the motion information of the current block to the HMVL, checking whether each element of the HMVL is different from the motion information of the current block; Including adding the motion information of the current block to the HMVL only when each element of the HMVL is different from the motion information of the current block.

[0219] In a possible implementation form of the device according to any of the above implementations of the first aspect or the first aspect itself, examining whether each element of the HMVL is different from the motion information of the current block involves comparison of corresponding motion vectors, and comparison of corresponding reference picture indices.

[0220] In a possible implementation form of the device according to any of the above implementations of the first aspect or the first aspect itself, examining whether each element of the HMVL is different from the motion information of the current block involves comparison of interpolation filter indices.

[0221] In a possible implementation form of the device according to any of the above implementations of the first aspect or the first aspect itself, the step of deriving motion information from the motion information of the first block, wherein the first block has a preset spatial or temporal positional relationship with the current block, further includes the step of

[0222] In a possible implementation form of the device according to any of the above implementations of the first aspect or the first aspect itself, the step of deriving motion information from the motion information of the second block, wherein the second block is reconstructed before the current block, further includes the step of

[0223] In a possible implementation form of the device according to any of the above implementations of the first aspect or the first aspect itself, here, the history-based motion information list (HMIL or HMVP table) is a subset of the candidate motion information list of the current block when the current block is in merge mode, or a subset of the candidate predicted motion information list of the current block when the current block is in AMVP mode.

[0224] In any of the above-described implementations of the first aspect or in a possible implementation form of the device according to the first aspect itself, the index of only one set of interpolation filters corresponds to one or more motion vectors of the HMVP candidates (such as the index of the same set of filters for both of the two MVs), or the index of one or more sets of interpolation filters corresponds to one or more motion vectors of the HMVP candidates, respectively.

[0225] An inter prediction method for a current block according to a second aspect of the present invention, a step of inter predicting a current block, the step including deriving an interpolation filter index (or an index of a set of interpolation filters) for the current block, deriving an interpolation filter index (or an index of a set of interpolation filters) for the current block is determining an HMVP candidate for the current block from an HMVP list (such as an HMVP table), the HMVP candidate including at least one motion vector, at least one reference picture index corresponding to the at least one motion vector, and at least one interpolation filter index (or an index of a set of interpolation filters) corresponding to the at least one motion vector (such as only one interpolation filter index or only one index of a set of interpolation filters for the entire candidate), and deriving or inferring or determining, as the interpolation filter index (or the index of the set of interpolation filters) for the current block, the interpolation filter index (or the index of the set of interpolation filters) of the determined or selected HMVP candidate, and One or more candidates (such as each candidate) in the HMVP list include at least one motion vector and an interpolation filter index (or an index of at least one set of interpolation filters) corresponding to the at least one motion vector.

[0226] In a possible implementation form of the method according to the second aspect itself, the interpolation filter index (or the index of a set of interpolation filters) corresponds to one or more motion vectors of the HMVP candidates, or one or more interpolation filter indexes (or indexes of one or more sets of interpolation filters) correspond to one or more motion vectors of the HMVP candidates.

[0227] A method for deriving an interpolation filter for an encoded unit encoded in merge mode based on the position of a current encoded unit within a CTU according to a third aspect of the present invention, analyzing or deriving a first merge index from a bitstream; selecting a merge candidate from a merge candidate list according to the first merge index; determining whether the current encoded unit overlaps with the upper or left boundary of the CTU; when the current encoded unit overlaps with the upper or left boundary of the CTU, setting the interpolation filter index (or the index of a set of interpolation filters) for the current encoded unit to a predefined value; otherwise, setting the interpolation filter index (or the index of a set of interpolation filters) for the current encoded unit to be equal to the interpolation filter index (or the index of a set of interpolation filters) of the selected merge candidate; selecting a first set of interpolation filters from N sets of interpolation filters (such as N predefined sets of interpolation filters) based on the interpolation filter index (or the index of a set of interpolation filters), where N is an integer greater than or equal to 2; selecting an interpolation filter from the first set of interpolation filters based on the fractional position (such as the fractional sample-based luma position (xFracL, yFracL) of the motion vector) of each motion vector of the selected merge candidate.

[0228] In a possible implementation form of the method according to the third aspect itself, a step of constructing a merge candidate list, wherein each candidate includes one or more motion vectors and an interpolation filter index (or an index of a set of interpolation filters that specifies one of a set of N interpolation filters, such as a set of N predefined interpolation filters), further includes the step.

[0229] In any of the above implementations of the third aspect or in a possible implementation form of the method according to the third aspect itself, here, the step of determining whether the current coding unit overlaps with the upper or left boundary of the CTB or CTU includes determining whether the upper left corner of the current block (such as the luma position (xCb, yCb) that specifies the upper left sample of the current coding block with reference to the upper left luma sample of the current picture) overlaps with the upper boundary of the CTU that includes the current coding unit.

[0230] In any of the above implementations of the third aspect or in a possible implementation form of the method according to the third aspect itself, determining whether the upper left corner of the current block overlaps with the upper boundary of the CTU that includes the current coding unit includes obtaining the vertical position (y coordinate) of the upper left corner of the current block, calculating the remainder after dividing the obtained vertical position (y coordinate) by the height of the CTU, if the calculated remainder is equal to 0, inferring that the upper left corner of the current block overlaps with the upper boundary of the current CTU, and otherwise inferring that the upper left corner of the current coding unit does not overlap with the upper boundary of the current CTU.

[0231] In any of the above implementations of the third aspect or in a possible implementation form of the method according to the third aspect itself, determining whether the upper left corner of the current coding unit overlaps with the upper boundary of the CTU that includes the current coding unit includes Calculate a first value as the floor value of the number obtained by dividing the vertical coordinate (coordinate y) at the upper left of the current block by the height of the CTU, calculate a second value as the floor value of the number obtained by dividing the upper left of the vertical coordinate of the inherited neighboring block by the height of the CTU, if the second value is equal to the first value, infer that the upper left corner of the current coding unit overlaps the upper boundary of the current CTU.

[0232] In a possible implementation form of the method according to any of the above implementations of the third aspect or the third aspect itself, determining whether the upper left corner of the current coding unit overlaps the upper boundary of the CTU containing the current coding unit, is to calculate a third value as (yCb >> CtbLog2SizeY) << CtbLog2SizeY, where yCb is the vertical coordinate (coordinate y) at the upper left of the current block, ">>" is a logical or arithmetic right bit shift, "<< " is a logical or arithmetic left bit shift, and CtbLog2SizeY is the binary logarithm scale of the size of the CTU, if (yCb - 1) is less than the third value, infer that the upper left corner of the current coding unit overlaps the upper boundary of the current CTU.

[0233] In a possible implementation form of the method according to any of the above implementations of the third aspect or the third aspect itself, the second predefined area includes or encompasses the upper left corner of the CTU containing the current block.

[0234] In a possible implementation form of the method according to any of the above implementations of the third aspect or the third aspect itself, determining whether the upper left corner of the current block overlaps the left boundary of the CTU containing the current block, is to obtain the horizontal position (x coordinate) of the upper left corner of the current coding unit, calculate the remainder after dividing the obtained horizontal position (x coordinate) by the width of the CTU, When the calculated remainder is equal to 0, it is presumed that the upper left corner of the current coding unit overlaps with the left boundary of the current CTU, and otherwise, it is presumed that the upper left corner of the current coding unit does not overlap with the left boundary of the current CTU.

[0235] In a possible implementation form of the method according to any of the above implementations of the third aspect or the third aspect itself, determining whether the upper left corner of the current coding unit overlaps with the left boundary of the CTU containing the current coding unit is calculating a fourth value as a floor value, where the horizontal coordinate (coordinate x) of the upper left corner of the current block is divided by the width of the CTU to obtain the floor value, is calculating a fifth value as a floor value, where the upper left of the vertical coordinator of the inherited neighboring block is divided by the width of the CTU to obtain the floor value, and when the fifth value is equal to the fourth value, presuming that the upper left corner of the current coding unit overlaps with the left boundary of the current CTU.

[0236] In a possible implementation form of the method according to any of the above implementations of the third aspect or the third aspect itself, determining whether the upper left corner of the current coding unit overlaps with the left boundary of the CTU containing the current coding unit is calculating a sixth value as (xCb >> CtbLog2SizeX) << CtbLog2SizeX, where xCb is the vertical coordinate (coordinate y) of the upper left corner of the current block, ">>" is a logical or arithmetic right bit shift, "<< " is a logical or arithmetic left bit shift, and CtbLog2SizeX is the binary logarithm scale of the width of the CTU, and when (xCb - 1) is less than the sixth value, presuming that the upper left corner of the current coding unit overlaps with the left boundary of the current CTU.

[0237] In any of the above implementations of the third aspect or in a possible implementation form of the method according to the third aspect itself, instead of a combination of left and right shift operations for N bits, a logical product with a bit mask that includes bit 0 at the lower N positions and bit 1 at other positions (for example, (yCb >> CtbLog2SizeY) << CtbLog2SizeY can be calculated as the logical product of yCb with a bit mask that includes bit 0 at the lower CtbLog2SizeY positions and bit 1 at other positions).

[0238] In any of the above implementations of the third aspect or in a possible implementation form of the method according to the third aspect itself, the selected interpolation filter is applied to the reference samples to generate a predicted sample at a fractional position between the reference samples, or the selected interpolation filter is used to generate a predicted sample within the current coding unit (such as generating a predicted sample for a lower block of the current coding unit).

[0239] A method for inter prediction for a current block according to a fourth aspect of the present invention, a method in which when a condition is satisfied, at least two luma positions have the same half - sample interpolation filter index and the same dual - prediction weight index.

[0240] In a possible implementation form of the method according to the fourth aspect itself, - when availableA1 is equal to TRUE, the luma positions (xNbA1, yNbA1) and (xNbB1, yNbB1), or the luma positions (xNbA1, yNbA1) and (xNbB0, yNbB0), or the luma positions (xNbA1, yNbA1) and (xNbA0, yNbA0), or the luma positions (xNbA1, yNbA1) and (xNbA0, yNbA0), or the luma positions (xNbA1, yNbA1) and (xNbB2, yNbB2) have the same dual - prediction weight index and the same half - sample interpolation filter index.

[0241] In a possible implementation form of the above-described implementation of any of the fourth aspects or the method according to the fourth aspect itself, when availableB1 is equal to TRUE, the luma positions (xNbB1, yNbB1) and (xNbB0, yNbB0), or the luma positions (xNbB1, yNbB1) and (xNbA0, yNbA0), or the luma positions (xNbB1, yNbB1) and (xNbB2, yNbB2) have the same dual-prediction weight index and the same half-sample interpolation filter index.

[0242] In a possible implementation form of the above-described implementation of any of the fourth aspects or the method according to the fourth aspect itself, when availableB0 is equal to TRUE, the luma positions (xNbB0, yNbB0) and (xNbA0, yNbA0), or the luma positions (xNbB0, yNbB0) and (xNbB2, yNbB2) have the same dual-prediction weight index and the same half-sample interpolation filter index.

[0243] In a possible implementation form of the above-described implementation of any of the fourth aspects or the method according to the fourth aspect itself, when availableA0 is equal to TRUE, the luma positions (xNbA0, yNbA0) and (xNbB2, yNbB2) have the same dual-prediction weight index and the same half-sample interpolation filter index.

[0244] An inter-prediction method for a current block according to a fifth aspect of the present invention, A method in which, when a condition is satisfied, an MVP candidate and a merge candidate have the same motion vector and the same reference index.

[0245] In a possible implementation form of the above-described implementation of any of the fifth aspects or the method according to the fifth aspect itself, obtaining a half-sample interpolation filter index, When the conditions are met, the MVP candidates and merge candidates have the same half - sample interpolation filter index, as well as the same motion vector and the same reference index.

[0246] In a possible implementation form of the method according to any of the above - described implementations of the fifth aspect or the fifth aspect itself, obtaining a half - sample interpolation filter index, When the conditions including the half - sample interpolation filter index are met, the MVP candidates and merge candidates have the same motion vector and the same reference index.

[0247] Details of a possible implementation of the derivation of motion information including the index of the set of interpolation filters for a block based on the merge candidate list of the proposed method (see step 1403 of method 1400 shown in FIG. 14) are described as follows in the form of a modification to the specification of the working draft of VVC. The modifications are emphasized.

[0248] 8.5.2 Derivation Process for Motion Vector Components and Reference Index 8.5.2.1 Overview The inputs to this process are as follows. - The luma position (xCb, yCb) of the top - left sample of the current luma - coded block with reference to the top - left luma sample of the current picture - A variable cbWidth that specifies the width of the current coded block in luma samples - A variable cbHeight that specifies the height of the current coded block in luma samples.

[0249] The outputs of this process are as follows. - Luma motion vectors mvL0[0][0] and mvL1[0][0] with 1 / 16 fractional - sample accuracy - Reference indices refIdxL0 and refIdxL1 - Prediction list utilization flags predFlagL0[0][0] and predFlagL1[0][0] - Half-sample interpolation filter index hpelIfIdx - Bi-prediction weight index bcwIdx.

[0250] Assume that the variable LX is RefPicList[X] of the current picture, where X is 0 or 1.

[0251] For the derivation of the variables mvL0[0][0] and mvL1[0][0], refIdxL0 and refIdxL1, and predFlagL0[0][0] and predFlagL1[0][0], the following is applied. - When general_merge_flag[xCb][yCb] is equal to 1, the derivation process for the luma motion vectors for the merge mode defined in Section 8.5.2.2 is called with the luma position (xCb, yCb), the variables cbWidth and cbHeight as inputs, and the output is the luma motion vectors mvL0[0][0], mvL1[0][0], the reference indices refIdxL0, refIdxL1, the prediction list usage flags predFlagL0[0][0] and predFlagL1[0][0], the half-sample interpolation filter index hpelIfIdx, the bi-prediction weight index bcwIdx, and the merge candidate list mergeCandList. - Otherwise, the following is applied. - For X replaced by either 0 or 1 in the variables predFlagLX[0][0], mvLX[0][0], and refIdxLX, in PRED_LX, and in the syntax elements ref_idx_lX and MvdLX, the following ordered steps are applied. 1. The variables refIdxLX and predFlagLX[0][0] are derived as follows. - When inter_pred_idc[ xCb ][ yCb ] is equal to PRED_LX or PRED_BI, refIdxLX = ref_idx_lX[ xCb ][ yCb ] (8-292) predFlagLX

[0000] [0 ] = 1 (8-293) - Otherwise, the variables refIdxLX and predFlagLX

[0000] [0 ] are defined as follows. refIdxLX = -1 (8-294) predFlagLX

[0000]

[0000] = 0 (8-295) 2. The variable mvdLX is derived as follows. mvdLX

[0000] = MvdLX[ xCb ][ yCb ]

[0000] (8-296) mvdLX

[0001] = MvdLX[ xCb ][ yCb ]

[0001] (8-297) 3. When predFlagLX

[0000]

[0000] is equal to 1, the derivation process for luma motion vector prediction in Clause 8.5.2.8 is called with the position ( xCb, yCb ) of the luma coded block, the width cbWidth of the coded block, the height cbHeight of the coded block, and the variable refIdxLX as inputs, and the output is mvpLX. 4. When predFlagLX

[0000]

[0000] is equal to 1, the luma motion vector mvLX

[0000]

[0000] is derived as follows. uLX

[0000] = ( mvpLX

[0000] + mvdLX

[0000] + 2 18 ) % 2 18 (8-298) mvLX

[0000]

[0000]

[0000] = ( uLX

[0000] >= 2 17 )? ( uLX

[0000] - 2 18 ) : uLX

[0000] (8-299) uLX

[0001] = ( mvpLX

[0001] + mvdLX

[0001] + 218 ) % 2 18 (8 - 300) mvLX

[0000]

[0000]

[0001] = (uLX

[0001] >= 2 17 ) ? (uLX

[0001] - 2 18 ) : uLX

[0001] (8 - 301) Note 1 - The values obtained as a result of mvLX

[0000]

[0000]

[0000] and mvLX

[0000]

[0000]

[0001] defined above are always between -2 17 and 2 17 including -1 and ranging from -2 17 to 2 17 to -1. - The half - sample interpolation filter index hpelIfIdx is derived as follows. hpelIfIdx = AmvrShift == 3? 1 : 0 (8 - 302) - The bi - prediction weight index bcwIdx is set to be equal to bcw_idx[xCb][yCb].

[0252] When all of the following conditions are true, refIdxL1 is set to be equal to -1, predFlagL1 is set to be equal to 0, and bcwIdx is set to be equal to 0. - predFlagL0

[0000]

[0000] is equal to 1 - predFlagL1

[0000]

[0000] is equal to 1 - The value of (cbWidth + cbHeight) is equal to 12.

[0253] The update process for the history-based motion vector predictor list defined in 8.5.2.16 is called using the luma motion vectors mvL0[0][0] and mvL1[0][0], the reference indices refIdxL0 and refIdxL1, the prediction list usage flags predFlagL0[0][0] and predFlagL1[0][0], the bi-prediction weight index bcwIdx, and the half-sample interpolation filter index hpelIfIdx.

[0254] It can be understood that the method is applicable for both uni prediction and bi-prediction. In the VVC working draft specification, two reference indices and two prediction list usage flags are transferred. In the case of uni prediction, predFlagL1 is set to be equal to 0, which means that L1 prediction is not used, and in this case, refIdxL1 is set to be equal to -1.

[0255] Details of a possible implementation of the derivation of history-based merge candidates (see step 1402 of method 1400 shown in Figure 14) of the proposed method are described as follows in the form of an amendment to the VVC draft specification. The amendment is emphasized.

[0256] 8.5.2.6 Derivation process for history-based merge candidates The input to this process is as follows. - The merge candidate list mergeCandList - The number of available merge candidates in the list numCurrMergeCand.

[0257] The output from this process is as follows. - The modified merge candidate list mergeCandList - The modified number of merge candidates in the list numCurrMergeCand.

[0258] The variables isPrunedA1 and isPrunedB1 are both set to be equal to FALSE. For each candidate in HmvpCandList[hMvpIdx] with index hMvpIdx = 1..NumHmvpCand, the following ordered steps are repeated until numCurrMergeCand is equal to MaxNumMergeCand - 1. 1. The variable sameMotion is derived as follows. - For any merge candidate N where N is A1 or B1, if all of the following conditions are true, sameMotion and isPrunedN are both set to be equal to TRUE. - hMvpIdx is less than or equal to 2 - Candidate HmvpCandList[NumHmvpCand - hMvpIdx] and merge candidate N have the same motion vector and the same reference index - isPrunedN is equal to FALSE - Otherwise, sameMotion is set to be equal to FALSE. 2. When sameMotion is equal to FALSE, candidate HmvpCandList[NumHmvpCand - hMvpIdx] is added to the merge candidate list as follows. mergeCandList[numCurrMergeCand++] = HmvpCandList[NumHmvpCand - hMvpIdx] (8 - 381)

[0259] Details of a first possible implementation of the update of the motion information (HMVP) candidate list based on the history of the proposed method (see steps 1303, 1313 shown in FIGS. 13A and 13B) are described as follows in the form of a modification to the draft specification of VVC. The modifications are emphasized.

[0260] 8.5.2.16 Update process for the history-based motion vector predictor candidate list The inputs to this process are as follows. - Luma motion vectors mvL0 and mvL1 with fractional sample accuracy of 1 / 16 - Reference indices refIdxL0 and refIdxL1 - Prediction list usage flags predFlagL0 and predFlagL1 - Dual prediction weight index gbiIdx - Index hpelIfIdx of a set of half sample interpolation filters

[0261] The MVP candidate hMvpCand consists of the luma motion vectors mvL0 and mvL1, the reference indices refIdxL0 and refIdxL1, the prediction list usage flags predFlagL0 and predFlagL1, the dual prediction weight index gbiIdx, and the index hpelIfIdx of a set of half sample interpolation filters.

[0262] The candidate list HmvpCandList is modified using the candidate hMvpCand by the following ordered steps. 1. The variable identicalCandExist is set to be equal to FALSE, and the variable removeIdx is set to be equal to 0. 2. When NumHmvpCand is greater than 0, for each index hMvpIdx where hMvpIdx = 0..NumHmvpCand - 1, the following steps are applied until identicalCandExist becomes equal to TRUE. - When hMvpCand is equal to HmvpCandList[ hMvpIdx ], identicalCandExist is set to be equal to TRUE, and removeIdx is set to be equal to hMvpIdx. 3. The candidate list HmvpCandList is updated as follows. - If identicalCandExist is equal to TRUE or NumHmvpCand is equal to MaxNumMergeCand - 1, the following applies. - For each index i where i = (removeIdx + 1)..(NumHmvpCand - 1), set HmvpCandList[i - 1] to be equal to HmvpCandList[i]. - Set HmvpCandList[NumHmvpCand - 1] to be equal to mvCand. - Otherwise (identicalCandExist is equal to FALSE and NumHmvpCand is less than MaxNumMergeCand - 1), the following applies. - Set HmvpCandList[NumHmvpCand++] to be equal to mvCand.

[0263] Details of a second possible implementation of the update of the motion information (HMVP) candidate list based on the history of the proposed method (see steps 1303, 1313 shown in FIGS. 13A and 13B, see steps 1502 - 1504 shown in FIG. 15) are described as follows in the form of a modification to the draft specification of VVC. The modifications are emphasized.

[0264] 8.5.2.16 Update process for the history - based motion vector predictor candidate list The inputs to this process are as follows. - Luma motion vectors mvL0 and mvL1 with 1 / 16 fractional sample accuracy - Reference indices refIdxL0 and refIdxL1 - Prediction list usage flags predFlagL0 and predFlagL1 - Bi - prediction weight index bcwIdx - Half - sample interpolation filter index hpelIfIdx.

[0265] The MVP candidate hMvpCand consists of the luma motion vectors mvL0 and mvL1, the reference indices refIdxL0 and refIdxL1, the prediction list usage flags predFlagL0 and predFlagL1, the bi-prediction weight index bcwIdx, and the half-sample interpolation filter index hpelIfIdx.

[0266] The candidate list HmvpCandList is modified using the candidate hMvpCand by the following ordered steps. 4. The variable identicalCandExist is set to be equal to FALSE, and the variable removeIdx is set to be equal to 0. 5. When NumHmvpCand is greater than 0, for each index hMvpIdx where hMvpIdx = 0..NumHmvpCand - 1, the following steps are applied until identicalCandExist is equal to TRUE. - When hMvpCand and HmvpCandList[hMvpIdx] have the same motion vector and the same reference index, identicalCandExist is set to be equal to TRUE, and removeIdx is set to be equal to hMvpIdx. 6. The candidate list HmvpCandList is updated as follows. - When identicalCandExist is equal to TRUE or NumHmvpCand is equal to 5, the following applies. - For each index i where i = (removeIdx + 1)..(NumHmvpCand - 1), HmvpCandList[ i - 1 ] is set to be equal to HmvpCandList[ i ]. - HmvpCandList[ NumHmvpCand - 1 ] is set to be equal to hMvpCand. - Otherwise (identicalCandExist is equal to FALSE and NumHmvpCand is less than 5), the following applies. - HmvpCandList[ NumHmvpCand++ ] is set to be equal to hMvpCand.

[0267] As can be seen from the above, the second implementation specifies the elements i) and ii) to be compared for the HMVP candidates, while the first implementation specifies all the elements (such as elements i), ii), and iii)) to be compared for the HMVP candidates.

[0268] Embodiments and exemplary embodiments have their respective methods and corresponding apparatuses.

[0269] FIG. 16 shows a diagram of an apparatus 1600 for constructing a history-based motion information candidate list including an HMI list acquisition unit 1601 and an HMI list update unit 1603.

[0270] The history-based motion information (HMI) candidate list acquisition unit 1601 is configured to acquire a history-based motion information candidate list, and the HMI list is an ordered list of N history-based motion information candidates H related to the motion information of a plurality of blocks preceding the block, where k = 0,..., N - 1, N is an integer greater than 0, and each history-based motion information candidate includes elements, namely, k iv) one or more motion vectors MV, v) one or more reference picture indices corresponding to the MV, and vi) an interpolation filter index The history-based motion information candidate list update unit 1603 is configured to update the HMI list based on the motion information of the block, and the motion information of the block includes elements, namely, iv) one or more motion vectors MV, v) one or more reference picture indices corresponding to the MV, and vi) an interpolation filter index including.

[0271] ​ In this embodiment of the present application, the HMI list acquisition unit 1601 and the HMI list update unit 1603 (corresponding to the inter-prediction module) of the encoder 20 or the decoder 30 provided are functional entities for implementing various execution steps included in the corresponding methods described above. That is, it will be understood that they have the steps of the method of the present application as well as functional entities for fully implementing the extensions and variations of these steps. For details, refer to the above description of the corresponding method. For the sake of brevity, the details will not be described again herein.

[0272] FIG. 17 shows a diagram of an inter-prediction device 1700 according to an embodiment of the present disclosure. The device 1700 is provided for determining motion information about a current block of a frame. The device 1700 is a list management unit 1701 configured to construct an ordered list of candidates Hk, the HMVP list, based on N histories related to the motion information of N previous blocks of a frame preceding the current block, where k = 0,..., N - 1, N is 1 or more, and each or at least one candidate based on a history includes motion information including i) one or more motion vectors MV, ii) one or more reference picture indices corresponding to the MV, and iii) an interpolation filter index or an index of a set of interpolation filters (such as a half-pel interpolation filter index), and the HMVP list management unit 1701 is further configured to add one or more candidates based on a history from the HMVP list to a motion information candidate list for the current block, and an information derivation unit 1703 configured to derive motion information based on the motion information candidate list.

[0273] In implementation, the list management unit 1701 is configured to compare at least one of the candidate elements based on each history of the HMI list with the corresponding element of the current block. The motion information addition unit is configured to add the motion information of the current block to the HMI list when at least one of each element of the candidates based on the history of the HMI list is different from the corresponding element of the motion information of the current block as a result of the comparison.

[0274] Correspondingly, in one example, the exemplary structure of the apparatus 1700 may correspond to the encoder 20 of FIG. 2. In another example, the exemplary structure of the apparatus 1700 may correspond to the decoder 30 of FIG. 3.

[0275] In another example, the exemplary structure of the apparatus 1700 may correspond to the inter prediction unit 244 of FIG. 2. In another example, the exemplary structure of the apparatus 1700 may correspond to the inter prediction unit 344 of FIG. 3.

[0276] It will be understood that the list management unit 1701 and the information derivation unit 1703 (corresponding to the inter prediction module) of the encoder 20 or the decoder 30 provided in this embodiment of the present application are functional entities for implementing various execution steps included in the above corresponding method, that is, they have the steps of the method of the present application and functional entities for fully implementing the extensions and variations of these steps. For details, please refer to the above description of the corresponding method. For the sake of brevity, the details are not described again in this specification.

[0277] More specifically, the following aspects related to the propagation of the SIF index across the CTU boundary are described.

[0278] As described above, when the SIF technology is applied in a mode that inherits motion information from the upper spatial neighboring blocks based on the current SIF design, if the current block is at the upper boundary of the CTU / CTB, the line memory is increased. In the description presented in this specification, the position of the current block is examined. When the current block is at the upper boundary of the CTU / CTB and inheriting motion information from the neighboring blocks of the upper left (B0), upper (B1), and upper right (B2), the IF index does not inherit from the neighboring blocks. Instead, a default value is used to reduce the use of the line memory.

[0279] In an aspect of the present disclosure, a method for inter prediction for a current block is provided. The method includes a step of inter predicting a block, including deriving an interpolation filter index for the current block based on the position of the current block (such as an encoding unit or an encoding block) within a coding tree block (CTB) or a coding tree unit (CTU) and the interpolation filter index inherited from the selected merge candidate.

[0280] FIG. 8 shows a flowchart of a method for deriving an index of a set of interpolation filters for a current block (such as an encoding unit or an encoding block) within a coding tree block (CTB) or a coding tree unit (CTU), including the following.

[0281] In step 803, the method includes a step of determining whether the current block overlaps with a predefined area of the CTB or CTU (such as the upper or left boundary of the CTB or CTU).

[0282] In step 804, the method includes the step of setting the index of the set of interpolation filters for the current block as the index of the set of interpolation filters of the selected candidate if the current block does not overlap with a predefined area of the CTU (for example, the current block does not overlap with the upper or left boundary of the CTB or CTU). The selected candidate can be, for example, a selected merge candidate or a selected MVP candidate. The selected candidate can also be a neighboring block corresponding to the selected merge candidate.

[0283] In step 805, the method includes the step of setting the index of the set of interpolation filters for the current block to a predefined value if the current block overlaps with a predefined area of the CTB or CTU (such as the upper or left boundary of the CTB or CTU).

[0284] Furthermore, in steps 801 - 802, the method includes constructing a candidate list. For the sake of brevity, the details are not described again herein.

[0285] To determine whether the current block is at the upper boundary of CTU 900, as shown in FIG. 9, the vertical coordinate (yCb) of the upper - left corner of the current block is examined. Assuming that the size of CTU 900 is equal to (1 << CtbLog2SizeY) x (1 << CtbLog2SizeY), if (yCb >> CtbLog2SizeY) << CtbLog2SizeY is not equal to yCb, the current block is not at the upper boundary of CTU 900 (scenario 1), and otherwise ((yCb >> CtbLog2SizeY) << CtbLog2SizeY is equal to yCb), the current block is at the upper boundary of CTU 900 (scenario 2).

[0286] According to an embodiment of the present disclosure, the selected candidate (such as the selected merge candidate) is a spatial merge candidate.

[0287] According to embodiments of the present disclosure, the vertical position associated with the spatial merge candidate is less than the vertical position of the current block, or the vertical position of the neighboring block corresponding to the spatial merge candidate is less than the vertical position of the current block.

[0288] According to embodiments of the present disclosure, the spatial merge candidate is the upper right candidate (B0 shown in FIG. 6), the upper candidate (B1 shown in FIG. 6), or the upper left candidate (B2 shown in FIG. 6).

[0289] According to embodiments of the present disclosure, here, the merge candidate is an affine merge candidate. The affine merge candidate is an inherited affine merge candidate, and "inherited" means that (i) the candidate is derived based on neighboring affine blocks, (ii) the affine model of the current block is inherited from the affine models of neighboring affine blocks, or (iii) the affine parameters of the current block are derived based on the affine parameters of neighboring affine blocks.

[0290] According to embodiments of the present disclosure, the inherited affine merge candidate is derived based on one of the spatially neighboring blocks, and the spatially neighboring blocks include the lower left block (such as A0 shown in FIG. 6), the left block (such as A1 shown in FIG. 6), the upper right block (such as B0 shown in FIG. 6), the upper block (such as B1 shown in FIG. 6), or the upper left block (such as B2 shown in FIG. 6).

[0291] According to embodiments of the present disclosure, the inherited affine merge candidate is derived based on a block having a vertical position less than the vertical position of the current block.

[0292] According to embodiments of the present disclosure, the inherited affine merge candidate is derived based on the upper right block (such as B0 shown in FIG. 6), the upper block (such as B1 shown in FIG. 6), or the upper left block (such as B2 shown in FIG. 6).

[0293] According to an embodiment of the present disclosure, a selected candidate (such as a selected merge candidate) is a sub-block merge candidate.

[0294] According to an embodiment of the present disclosure, here, a predefined area of the CTU coincides with the CTB or CTU.

[0295] According to an embodiment of the present disclosure, the step of determining whether the current block overlaps with a predefined area is based on the position of the upper left corner of the coding unit (such as the horizontal and vertical positions of the upper left sample of the current block, etc.), the position of the upper left corner of the current block (such as the luma position (xCb, yCb) that designates the upper left sample of the current block with reference to the upper left luma sample of the current picture).

[0296] According to an embodiment of the present disclosure, the current block is presumed to overlap with a predefined area (such as the upper boundary of the CTU) when the upper left corner of the current block overlaps with a second predefined area (such as the upper left corner of the CTU).

[0297] According to an embodiment of the present disclosure, the second predefined area includes or encompasses the upper boundary of the CTU that contains the current block (for example, the upper left corner of the CTU includes or encompasses the upper boundary or left boundary of the CTU that contains the current block).

[0298] According to an embodiment of the present disclosure, the step of determining whether the current block overlaps with a predefined area of the CTB or CTU includes determining whether the upper left corner of the current block (such as the luma position (xCb, yCb) that designates the upper left sample of the current block with reference to the upper left luma sample of the current picture) overlaps with the upper boundary of the CTU that contains the current coding unit.

[0299] According to an embodiment of the present disclosure, determining whether the upper left corner of the current block overlaps with the upper boundary of the CTU that contains the current coding unit is Obtaining the vertical position (y - coordinate) of the upper - left corner of the current block, and Calculating the remainder after dividing the obtained vertical position (y - coordinate) by the height of the CTU, and When the calculated remainder is equal to 0, it is presumed that the upper - left corner of the current block overlaps with the upper boundary of the current CTU, and when it is not, it is presumed that the upper - left corner of the current coding unit does not overlap with the upper boundary of the current CTU. This includes

[0300] According to an embodiment of the present disclosure, determining whether the upper - left corner of the current coding unit overlaps with the upper boundary of the CTU containing the current coding unit is Calculating a first value as a floor value, where the upper - left vertical coordinate (coordinate y) of the current block is divided by the height of the CTU to obtain the floor value, and Calculating a second value as a floor value, where the upper - left of the vertical coordinate of the inherited neighboring block is divided by the height of the CTU to obtain the floor value, and When the second value is equal to the first value, presuming that the upper - left corner of the current coding unit overlaps with the upper boundary of the current CTU. This includes

[0301] According to an embodiment of the present disclosure, determining whether the upper - left corner of the current coding unit overlaps with the upper boundary of the CTU containing the current coding unit is Calculating a third value as (yCb >> CtbLog2SizeY) << CtbLog2SizeY, where yCb is the upper - left vertical coordinate (coordinate y) of the current block, ">>" is a logical or arithmetic right - bit shift, "<<" is a logical or arithmetic left - bit shift, and CtbLog2SizeY is the binary logarithm scale of the size of the CTU or CTB, and When (yCb - 1) is less than the third value, presuming that the upper - left corner of the current coding unit overlaps with the upper boundary of the current CTU. This includes

[0302] According to an embodiment of the present disclosure, the second predefined area includes or encompasses the upper left corner of the CTU including the current block.

[0303] According to an embodiment of the present disclosure, determining whether the upper left corner of the current block overlaps with the left boundary of the CTU including the current block includes: obtaining the horizontal position (x coordinate) of the upper left corner of the current coding unit; calculating the remainder after dividing the obtained horizontal position (x coordinate) by the width of the CTU; if the calculated remainder is equal to 0, presuming that the upper left corner of the current coding unit overlaps with the left boundary of the current CTU; otherwise, presuming that the upper left corner of the current coding unit does not overlap with the left boundary of the current CTU.

[0304] According to an embodiment of the present disclosure, determining whether the upper left corner of the current coding unit overlaps with the left boundary of the CTU including the current coding unit includes: calculating a fourth value as a floor value, where the upper left horizontal coordinate (coordinate x) of the current block is divided by the width of the CTU to obtain the floor value; calculating a fifth value as a floor value, where the upper left of the vertical coordinator of the inherited neighboring block is divided by the width of the CTU to obtain the floor value; if the fifth value is equal to the fourth value, presuming that the upper left corner of the current coding unit overlaps with the left boundary of the current CTU.

[0305] According to an embodiment of the present disclosure, determining whether the upper left corner of the current coding unit overlaps with the left boundary of the CTU including the current coding unit includes: Calculating a sixth value as ((xCb >> CtbLog2SizeX) << CtbLog2SizeX), where xCb is the vertical coordinate (coordinate y) of the upper left corner of the current block, ">>" is a logical or arithmetic right bit shift, "<< " is a logical or arithmetic left bit shift, and CtbLog2SizeX is the binary logarithm scale of the width of the CTU, and when (xCb - 1) is less than the sixth value, inferring that the upper left corner of the current coding unit overlaps the left boundary of the current CTU.

[0306] According to an embodiment of the present disclosure, instead of a combination of left and right shift operations on N bits, a logical product with a bit mask that includes bit 0 at the lower N positions and bit 1 at other positions (for example, (yCb >> CtbLog2SizeY) << CtbLog2SizeY can be calculated as the logical product of yCb with a bit mask that includes bit 0 at the lower CtbLog2SizeY positions and bit 1 at other positions). For example, if yCb is in the range of [0, 2 32 - 1] and CtbLog2SizeY is equal to 7, the value of yCb & 0xFFFFFF80 can be calculated instead of (yCb >> CtbLog2SizeY) << CtbLog2SizeY. Here, 0xFFFFFF80 is a bit mask that includes 0 at the lower 7 positions and 1 at other positions.

[0307] According to an embodiment of the present disclosure, a logical or arithmetic shift is used to calculate the floor value of the result of division. (For example, an exemplary floor value of a / 2 n can be calculated as a >> n).

[0308] According to an embodiment of the present disclosure, the second predefined area includes or encompasses only the upper boundary of the CTU that includes the current block.

[0309] According to an embodiment of the present disclosure, the second predefined area includes or encompasses only the left boundary of the CTU including the current block.

[0310] According to an embodiment of the present disclosure, the second predefined area includes or encompasses only the upper and left boundaries of the CTU including the current block.

[0311] According to an embodiment of the present disclosure, the step of setting the index of the set of interpolation filters for the current block to a predefined value includes setting the index of the set of interpolation filters for the current block to a seventh value, where the seventh value is determined before the construction of the merge list.

[0312] According to an embodiment of the present disclosure, determining the seventh value includes determining the index of the set of interpolation filters for one of the spatially neighboring blocks of the current block, and setting the seventh value to be equal to the determined index of the set of interpolation filters.

[0313] According to an embodiment of the present disclosure, "one of the spatially neighboring blocks" means the left neighboring block (this block is referred to as A1 in FIG. 6).

[0314] Details of a possible implementation of the propagation of the SIF index across the CTU boundary of the proposed method (the process is shown in FIGS. 8 and 9) are described as follows in the form of a modification to the specification of the working draft of the SIF proposal. The modifications are emphasized.

[0315] 8.5.2.3 Derivation Process for Spatial Merge Candidates The inputs to this process are as follows. - The luma position (xCb, yCb) of the upper left sample of the current luma coded block with reference to the upper left luma sample of the current picture - The variable cbWidth specifying the width of the current coded block in luma samples - A variable cbHeight that specifies the height of the current coded block in luma samples.

[0316] The output of this process is as follows, assuming X is 0 or 1. - Flags availableFlagA0, availableFlagA1, availableFlagB0, availableFlagB1, and availableFlagB2 indicating the availability of neighboring coding units - Reference indices refIdxLXA0, refIdxLXA1, refIdxLXB0, refIdxLXB1, and refIdxLXB2 of neighboring coding units - Prediction list usage flags predFlagLXA0, predFlagLXA1, predFlagLXB0, predFlagLXB1, and predFlagLXB2 of neighboring coding units - Motion vectors mvLXA0, mvLXA1, mvLXB0, mvLXB1, and mvLXB2 with 1 / 16 fractional sample accuracy of neighboring coding units - Half-sample interpolation filter indices hpelIfIdxA0, hpelIfIdxA1, hpelIfIdxB0, hpelIfIdxB1, and hpelIfIdxB2 - Bi-prediction weight indices gbiIdxA0, gbiIdxA1, gbiIdxB0, gbiIdxB1, and gbiIdxB2.

[0317] For the derivation of availableFlagA1, refIdxLXA1, predFlagLXA1, and mvLXA1, the following applies. - The luma position (xNbA1, yNbA1) within the neighboring luma coded block is set to be equal to (xCb - 1, yCb + cbHeight - 1). - The availability derivation process for the block defined in item 6.4 is called with the current luma position (xCurr, yCurr) and the neighboring luma position (xNbA1, yNbA1) set to be equal to (xCb, yCb) as inputs, and the output is assigned to the availability flag availableA1 of the block. - The variables availableFlagA1, refIdxLXA1, predFlagLXA1, and mvLXA1 are derived as follows. - If availableA1 is equal to FALSE, availableFlagA1 is set to be equal to 0, both components of mvLXA1 are set to be equal to 0, refIdxLXA1 is set to be equal to -1, predFlagLXA1 is set to be equal to 0, X is 0 or 1, and gbiIdxA1 is set to be equal to 0. - Otherwise, availableFlagA1 is set to be equal to 1, and the following assignments are made. mvLXA1 = MvLX[xNbA1][yNbA1] (8 - 294) refIdxLXA1 = RefIdxLX[xNbA1][yNbA1] (8 - 295) predFlagLXA1 = PredFlagLX[xNbA1][yNbA1] (8 - 296) hpelIfIdxA1 = HpelIfIdx[xNbA1][yNbA1] (8 - 297) gbiIdxA1 = GbiIdx[xNbA1][yNbA1] (8 - 297)

[0318] For the derivation of availableFlagB1, refIdxLXB1, predFlagLXB1, and mvLXB1, the following applies. - The luma position (xNbB1, yNbB1) within the neighboring luma coded block is set to be equal to (xCb + cbWidth - 1, yCb - 1). - The availability derivation process for the block defined in item 6.4 is called with the current luma position (xCurr, yCurr) and neighboring luma positions (xNbB1, yNbB1) set to be equal to (xCb, yCb), and the output is assigned to the block's availability flag availableB1. - Variables availableFlagB1, refIdxLXB1, predFlagLXB1, and mvLXB1 are derived as follows. - If one or more of the following conditions are true, availableFlagB1 is set to be equal to 0, both components of mvLXB1 are set to be equal to 0, refIdxLXB1 is set to be equal to -1, predFlagLXB1 is set to be equal to 0, X is 0 or 1, and gbiIdxB1 is set to be equal to 0. - availableB1 is equal to FALSE. - availableA1 is equal to TRUE, and the luma positions (xNbA1, yNbA1) and (xNbB1, yNbB1) have the same motion vector and the same reference index. - Otherwise, availableFlagB1 is set to be equal to 1, and the following assignments are made. mvLXB1 = MvLX[xNbB1][yNbB1] (8 - 298) refIdxLXB1 = RefIdxLX[xNbB1][yNbB1] (8 - 299) predFlagLXB1 = PredFlagLX[xNbB1][yNbB1] (8 - 300) If (yCb - 1) < ((yCb >> CtbLog2SizeY) << CtbLog2SizeY), hpelIfIdxB1 = 2 Otherwise, hpelIfIdxB1 = HpelIfIdx[xNbB1][yNbB1] gbiIdxB1 = GbiIdx[xNbB1][yNbB1] (8 - 301)

[0319] For the derivation of availableFlagB0, refIdxLXB0, predFlagLXB0, and mvLXB0, the following applies. - The luma position (xNbB0, yNbB0) in the neighboring luma - coded block is set to be equal to (xCb + cbWidth, yCb - 1). - The availability - derivation process for the block defined in Clause 6.4 is called with the current luma position (xCurr, yCurr) and the neighboring luma position (xNbB0, yNbB0) set to be equal to (xCb, yCb), and the output is assigned to the block's availability flag availableB0. - The variables availableFlagB0, refIdxLXB0, predFlagLXB0, and mvLXB0 are derived as follows. - If one or more of the following conditions are true, availableFlagB0 is set to be equal to 0, both components of mvLXB0 are set to be equal to 0, refIdxLXB0 is set to be equal to - 1, predFlagLXB0 is set to be equal to 0, X is 0 or 1, and gbiIdxB0 is set to be equal to 0. - availableB0 is equal to FALSE. - availableB1 is equal to TRUE, and the luma positions (xNbB1, yNbB1) and (xNbB0, yNbB0) have the same motion vector and the same reference index. - availableA1 is equal to TRUE, the luma positions (xNbA1, yNbA1) and (xNbB0, yNbB0) have the same motion vector and the same reference index, and merge_triangle_flag[xCb][yCb] is equal to 1. - Otherwise, availableFlagB0 is set to be equal to 1, and the following assignments are made. mvLXB0 = MvLX[xNbB0][yNbB0] (8 - 302) refIdxLXB0 = RefIdxLX[xNbB0][yNbB0] (8 - 303) predFlagLXB0 = PredFlagLX[xNbB0][yNbB0] (8 - 304) If (yCb - 1) < ((yCb >> CtbLog2SizeY) << CtbLog2SizeY), hpelIfIdxB0 = 2 Otherwise, hpelIfIdxB0 = HpelIfIdx[xNbB0][yNbB0] (8 - 305) gbiIdxB0 = GbiIdx[xNbB0][yNbB0] (8 - 305)

[0320] For the derivation of availableFlagA0, refIdxLXA0, predFlagLXA0, and mvLXA0, the following applies. - The luma position (xNbA0, yNbA0) within the neighboring luma - coded block is set to be equal to (xCb - 1, yCb + cbWidth). - The availability - derivation process for the block defined in Clause 6.4 is called with the current luma position (xCurr, yCurr) and the neighboring luma position (xNbA0, yNbA0) set to be equal to (xCb, yCb), and the output is assigned to the block's availability flag availableA0. - The variables availableFlagA0, refIdxLXA0, predFlagLXA0, and mvLXA0 are derived as follows. - If one or more of the following conditions are true, availableFlagA0 is set equal to 0, both components of mvLXA0 are set equal to 0, refIdxLXA0 is set equal to -1, predFlagLXA0 is set equal to 0, X is 0 or 1, and gbiIdxA0 is set equal to 0. - availableA0 is equal to FALSE. - availableA1 is equal to TRUE, and the luma positions (xNbA1, yNbA1) and (xNbA0, yNbA0) have the same motion vector and the same reference index. - availableB1 is equal to TRUE, the luma positions (xNbB1, yNbB1) and (xNbA0, yNbA0) have the same motion vector and the same reference index, and merge_triangle_flag[xCb][yCb] is equal to 1. - availableB0 is equal to TRUE, the luma positions (xNbB0, yNbB0) and (xNbA0, yNbA0) have the same motion vector and the same reference index, and merge_triangle_flag[xCb][yCb] is equal to 1. - Otherwise, availableFlagA0 is set equal to 1, and the following assignments are made. mvLXA0 = MvLX[xNbA0][yNbA0] (8 - 306) refIdxLXA0 = RefIdxLX[xNbA0][yNbA0] (8 - 307) predFlagLXA0 = PredFlagLX[xNbA0][yNbA0] (8 - 308) hpelIfIdxA0 = HpelIfIdx[xNbA0][yNbA0] (8 - 309) gbiIdxA0 = GbiIdx[xNbA0][yNbA0] (8 - 309)

[0321] For the derivation of availableFlagB2, refIdxLXB2, predFlagLXB2, and mvLXB2, the following applies. - The luma position (xNbB2, yNbB2) within the neighboring luma coded block is set to be equal to (xCb - 1, yCb - 1). - The availability derivation process for the block specified in Clause 6.4 is called with the current luma position (xCurr, yCurr) and the neighboring luma position (xNbB2, yNbB2) set to be equal to (xCb, yCb), and the output is assigned to the availability flag availableB2 of the block. - The variables availableFlagB2, refIdxLXB2, predFlagLXB2, and mvLXB2 are derived as follows. - If one or more of the following conditions are true, availableFlagB2 is set to be equal to 0, both components of mvLXB2 are set to be equal to 0, refIdxLXB2 is set to be equal to -1, predFlagLXB2 is set to be equal to 0, X is 0 or 1, and gbiIdxB2 is set to be equal to 0. - availableB2 is equal to FALSE. - availableA1 is equal to TRUE, and the luma positions (xNbA1, yNbA1) and (xNbB2, yNbB2) have the same motion vector and the same reference index. - availableB1 is equal to TRUE, and the luma positions (xNbB1, yNbB1) and (xNbB2, yNbB2) have the same motion vector and the same reference index. - availableB0 is equal to TRUE, the luma positions (xNbB0, yNbB0) and (xNbB2, yNbB2) have the same motion vector and the same reference index, and merge_triangle_flag[xCb][yCb] is equal to 1. - availableA0 is equal to TRUE, the luma positions (xNbA0, yNbA0) and (xNbB2, yNbB2) have the same motion vector and the same reference index, and merge_triangle_flag[xCb][yCb] is equal to 1. - availableFlagA0 + availableFlagA1 + availableFlagB0 + availableFlagB1 is equal to 4, and merge_triangle_flag[xCb][yCb] is equal to 0. - Otherwise, availableFlagB2 is set to be equal to 1, and the following assignments are made. mvLXB2 = MvLX[xNbB2][yNbB2] (8 - 310) refIdxLXB2 = RefIdxLX[xNbB2][yNbB2] (8 - 311) predFlagLXB2 = PredFlagLX[xNbB2][yNbB2] (8 - 312) If (yCb - 1) < ((yCb >> CtbLog2SizeY) << CtbLog2SizeY), hpelIfIdxB2 = 2 Otherwise, hpelIfIdxB2 = HpelIfIdx[xNbB2][yNbB2] (8 - 313) gbiIdxB2 = GbiIdx[xNbB2][yNbB2] (8 - 313)

[0322] As can be understood from the above content, the half-pixel interpolation filter index of the blocks adjacent to the current block is determined based on whether the current block overlaps with the boundary of the CTU. For example, equations (8-298) to (8-301) show the steps for determining the half-pixel interpolation filter index of the adjacent block B1 (see FIGS. 8 and 9). Equations (8-302) to (8-305) show the steps for determining the half-pixel interpolation filter index of the adjacent block B0 (see FIGS. 8 and 9). Equations (8-310) to (8-313) show the steps for determining the half-pixel interpolation filter index of the adjacent block B2 (see FIGS. 8 and 9).

[0323] Based on the above, the present disclosure is directed to storing the SIF index in the HMVP table (or propagating the SIF index via the HMVP table) and using that SIF index for HMVP candidates in the merge list construction process. The SIF method is used to select an appropriate interpolation filter (IF) according to the content, that is, for regions with sharp edges, a normal DCT-based IF is used, and for smooth regions (or when it is not necessary to maintain sharp edges), an alternative 6-tap IF (Gaussian filter) is used. For normal inter prediction, the IF index is explicitly signaled, while for the merge mode, not only are the MV and reference picture index borrowed from the spatial candidates of the corresponding merge (HMVP merge candidates), but the IF index is also borrowed from the spatial candidates of the corresponding merge. This is in contrast to the normal design where the IF index is not propagated via the HMVP table. Thus, in the normal design, for blocks coded in the merge mode and merge candidates obtained from the HMVP table, an alternative IF may not be used. The HMVP table is used to store motion information from neighboring blocks (but not necessarily from adjacent blocks as in the case of normal spatial merge candidates). The idea of HMVP is to use motion information from blocks that are spatially close to the current block but not necessarily adjacent (blocks from some spatial neighborhood). Thus, for example, if the current block contains smooth content and the adjacent blocks contain mostly sharp content, it may not be efficient to borrow the IF index from the adjacent blocks. However, smooth content can be within some spatial neighborhood block of the current block, and the motion information of such a block can be stored in the HMVP table. Propagating the IF index through the HMVP table as shown herein enables the use of an appropriate IF for the current block (e.g., a Gaussian filter can be selected for smooth content or when it is not necessary to maintain sharp edges).This brings the advantage of improving coding efficiency. Without the present invention, the default IF index (corresponding to the IF based on an 8-tap DCT) would always be used for HMVP merge candidates, and the details of the content of the current block (whether sharp edges need to be maintained) could not be considered.

[0324] Furthermore, the present disclosure also targets using only the MV and reference picture index without using the SIF index in the pruning process during the update of the HMVP table.

[0325] When a new element is added to the HMVP record, it is necessary to determine whether this new element is used for record comparison. A simple approach is to use all elements of the HMVP record in record comparison (default C-style structure comparison). However, in the present disclosure, the IF index is not used for HMVP record comparison. There are two reasons for this design.

[0326] The first reason is to avoid additional computational complexity. Each comparison operation incurs additional computational operations in the HMVP table update process and the merge candidate construction process. Therefore, when the comparison operation can be reduced or eliminated, the computational complexity can be reduced, thereby improving coding efficiency. From an implementation perspective, if unnecessary comparisons can be avoided here, a better implementation can be achieved. Therefore, instead of the default C-style structure comparison of the HMVP record, the elements of the HMVP record are divided into two subsets, namely, the elements used for record comparison and the elements not used for record comparison.

[0327] The second reason is to maintain the diversity of the HMVP records. For example, having two HMVP records with the same MV and reference index and only their IF indexes being different is not efficient because these two records are not "different enough". Instead, during the HMVP table update process, it is more efficient to consider those HMVP records to be the same. In this case, a new record that is the same as the existing record except for the IF index is not added to the HMVP table. As a result, "old" records that are "different enough" from other records (having different MVs or reference indexes) are maintained. In other words, for a new record to be added to the HMVP table, this new record should not only be bit - different from the existing records, but this new record needs to be "significantly different". From the perspective of coding efficiency, it is more efficient to have two records with different MVs or reference indexes in the HMVP table rather than two records that only differ in the IF index.

[0328] Furthermore, the present disclosure also targets the constraints regarding the merging of parameters of a switchable interpolation filter (SIF) for saving line memory. Compared with the previous design of the SIF, the disclosed method introduces a way to apply the SIF with a motion information inheritance tool without increased line memory, which saves the bandwidth of the line memory. Regarding high - resolution cases, the saving of line memory significantly reduces the cost of on - chip memory.

[0329] The modified IF index derivation method is coded in merge mode and improves coding efficiency by using a more appropriate IF index for CUs having a merge index corresponding to a merge candidate based on history.

[0330] The mathematical operators used in this application are similar to those used in the C programming language and may refer to the mathematical operators in the HEVC standard specifications. However, the results of integer division and arithmetic shift operations are more precisely defined, and additional operations such as exponentiation and division of real values are defined. The numbering and counting rules generally start from 0. For example, "the first" is equivalent to number 0, "the second" is equivalent to number 1, and so on.

[0331] The following is an explanation of the application of the encoding method and decoding method shown in the above embodiments and the systems using them.

[0332] FIG. 18 is a block diagram showing a content supply system 3100 for realizing a content delivery service. This content supply system 3100 includes a capture device 3102 and a terminal device 3106, and optionally includes a display 3126. The capture device 3102 communicates with the terminal device 3106 via a communication link 3104. The communication link may include the communication channel 13 described above. The communication link 3104 includes, but is not limited to, WIFI, Ethernet, cable, wireless (3G / 4G / 5G), USB, or any combination of these types.

[0333] The capture device 3102 can generate data and encode the data by the encoding method shown in the above embodiments. Alternatively, the capture device 3102 can deliver the data to a streaming server (not shown), and the server encodes the data and transmits the encoded data to the terminal device 3106. The capture device 3102 includes, but is not limited to, a camera, a smartphone or a smart pad, a computer or a laptop, a video conferencing system, a PDA, an in-vehicle device, or any combination thereof. For example, the capture device 3102 may include the above-described source device 12. When the data includes video, the video encoder 20 included in the capture device 3102 can actually perform video encoding processing. When the data includes audio (i.e., voice), the audio encoder included in the capture device 3102 can actually perform audio encoding processing. For some actual scenarios, the capture device 3102 distributes the encoded video and audio data by multiplexing them together. For other actual scenarios, for example, in a video conferencing system, the encoded audio data and the encoded video data are not multiplexed. The capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.

[0334] In the content supply system 3100, the terminal device 310 receives and plays back the encoded data. The terminal device 3106 can be a smartphone or smart pad 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a TV 3114, a set-top box (STB) 3116, a video conferencing system 3118, a video surveillance system 3120, a personal digital assistant (PDA) 3122, an in-vehicle device 3124, or a combination of any of these, which are devices having the ability to receive and restore data. For example, the terminal device 3106 may include the above-mentioned destination device 14. When the encoded data includes video, the video decoder 30 included in the terminal device is prioritized to perform video decoding. When the encoded data includes audio, the audio decoder included in the terminal device is prioritized to perform audio decoding processing.

[0335] Regarding a terminal device having a display, such as a smartphone or smart pad 3108, a computer or laptop 3110, a network video recorder (NVR) / digital video recorder (DVR) 3112, a TV 3114, a personal digital assistant (PDA), or an in-vehicle device 3124, the terminal device can supply the decoded data to the display of the terminal device. Regarding a terminal device without a display, such as an STB 3116, a video conferencing system 3118, or a video surveillance system 3120, it communicates with an external display 3126, and the decoded data is received and displayed.

[0336] When each device of this system performs encoding or decoding, the picture encoding device or picture decoding device shown in the above embodiments can be used.

[0337] FIG. 19 is a diagram showing the structure of an example of the terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, the protocol progress unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, a real-time streaming protocol (RTSP), a hypertext transfer protocol (HTTP), an HTTP live streaming protocol (HLS), MPEG-DASH, a real-time transport protocol (RTP), a real-time messaging protocol (RTMP), or any combination of these types.

[0338] After the protocol progress unit 3202 processes the stream, a stream file is generated. The file is output to the demultiplexing unit 3204. The demultiplexing unit 3204 can separate the multiplexed data into encoded audio data and encoded video data. As described above, for some actual scenarios, for example, in a video conferencing system, the encoded audio data and the encoded video data are not multiplexed. In this situation, the encoded data is sent to the video decoder 3206 and the audio decoder 3208 without passing through the demultiplexing unit 3204.

[0339] Through the multiplexing release process, a video elementary stream (ES), an audio ES, and optionally subtitles are generated. A video decoder 3206 including the video decoder 30 described in the above embodiment decodes the video ES by the decoding method shown in the above embodiment to generate a video frame, and supplies this data to the synchronization unit 3212. The audio decoder 3208 decodes the audio ES to generate an audio frame, and supplies this data to the synchronization unit 3212. Alternatively, the video frame can be stored in a buffer (not shown in FIG. 19) before supplying the video frame to the synchronization unit 3212. Similarly, the audio frame can be stored in a buffer (not shown in FIG. Y) before supplying the audio frame to the synchronization unit 3212.

[0340] The synchronization unit 3212 synchronizes the video frame and the audio frame, and supplies the video / audio to the video / audio display 3214. For example, the synchronization unit 3212 synchronizes the presentation of video information and audio information. The information can be coded in a syntax that uses time stamps related to the presentation of the coded audio data and visual data as well as time stamps related to the delivery of the data stream itself.

[0341] When subtitles are included in the stream, the subtitle decoder 3210 decodes the subtitles, synchronizes the subtitles with the video frame and the audio frame, and supplies the video / audio / subtitle to the video / audio / subtitle display 3216.

[0342] The present invention is not limited to the above-described system, and either the picture encoding device or the picture decoding device of the above-described embodiment can be incorporated into other systems, for example, an automotive system.

[0343] Although embodiments of the present invention have been mainly described based on video coding, embodiments of the coding system 10, the encoder 20, and the decoder 30 (and the system 10 correspondingly), as well as other embodiments described herein, may be configured for the processing or coding of a still picture, i.e., an individual picture independent of any preceding or subsequent pictures similar to video coding. It should be noted that generally, when the processing coding of a picture is limited to a single picture 17, only the inter prediction units 244 (encoder) and 344 (decoder) may not be available. All other functions (also referred to as tools or technologies) of the video encoder 20 and the video decoder 30, for example, residual calculation 204 / 304, transform 206, quantization 208, inverse quantization 210 / 310, (inverse) transform 212 / 312, segmentation 262 / 362, intra prediction 254 / 354, and / or loop filters 220, 320, and entropy coding 270, and entropy decoding 304 may be equally used for the processing of a still picture.

[0344] For example, the encoder 20 and the decoder 30, and embodiments of the functions described herein in connection with, for example, the encoder 20 and the decoder 30, may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on a computer-readable medium as one or more instructions or code or transmitted over a communication medium and executed by a hardware-based processing unit. The computer-readable medium may include a computer-readable storage medium corresponding to a tangible medium such as a data storage medium, or a communication medium including any medium that facilitates transfer of a computer program from one place to another, for example, by a communication protocol. Thus, generally, the computer-readable medium may correspond to (1) a tangible computer-readable storage medium that is non-transitory or (2) a communication medium such as a signal or a carrier wave. The data storage medium may be any available medium 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.

[0345] By way of example and not limitation, such computer-readable storage media can include 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 the desired program code in the form of instructions or data structures and that is accessible by a computer. Also, any connection can be properly termed a computer-readable medium. For example, if the instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but instead are directed to non-transitory, tangible storage media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray (registered trademark) disc, where disk typically magnetically reproduces data while disc optically reproduces data using a laser. Combinations of the above should also be included within the scope of computer-readable media.

[0346] The commands can 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 circuits. Thus, the term "processor," as used herein, can refer to either the structures described above or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functions described herein can be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into a combined codec. Also, the techniques can be implemented entirely in one or more circuits or logic elements.

[0347] The techniques of the present disclosure can be implemented in a variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chipset). Although various components, modules, or units are described in the present disclosure to highlight aspects of the functionality of a device configured to execute the disclosed techniques, implementation by different hardware units is not necessarily required. Rather, as described above, the various units can be provided by a combination in a codec hardware unit or by a set of interoperable hardware units including one or more of the above processors in conjunction with suitable software and / or firmware.

Description of the Symbols

[0348] 10 Video coding system, coding system 12 Source device 13 Encoded picture data, communication channel 14 Destination device 16 Picture source 17 Picture, picture data, raw picture, raw picture data, monochrome picture, color picture, current picture 18 Preprocessor, preprocessing unit, picture preprocessor 19 Preprocessed picture, preprocessed picture data 20 Video encoder, encoder 21 Encoded picture data, encoded bitstream 22 Communication interface, communication unit 28 Communication interface, communication unit 30 Decoder, video decoder 31 Decoded picture data, decoded picture 32 Postprocessor, postprocessing unit 33 Postprocessed picture data, postprocessed picture 34 Display device 46 Processing circuit 100 Video encoder 201 Input, input interface 203 Picture block, original block, current block, segmented block, current picture block 204 Residual calculation unit, residual calculation 205 Residual block, residual 206 Transformation processing unit, transformation 207 Transformation coefficient 208 Quantization unit, quantization 209 Quantized coefficient, quantized transformation coefficient, quantized residual coefficient 210 Inverse quantization unit, inverse quantization 211 Dequantized coefficient, dequantized residual coefficient 212 Inverse transformation processing unit, (inverse) transformation 213 Reconstructed residual block, dequantized coefficient, transformation block 214 Reconstruction unit, adder, summer 215 Reconstructed block 216 Buffer 220 Loop filter unit, loop filter 221 Filtered block, filtered reconstructed block 230 Decoded picture buffer (DPB) 231 Decoded picture 244 Inter prediction unit 254 Intra prediction unit, inter prediction unit, intra prediction 260 Mode selection unit 262 Partitioning unit, partitioning 265 Prediction block, predictor 266 Syntax element 270 Entropy coding unit, entropy coding 272 Output, output interface 304 Entropy decoding unit, residual calculation, entropy decoding 309 Quantized coefficient 310 Inverse quantization unit, inverse quantization 311 Dequantized coefficient, transform coefficient 312 Inverse transform processing unit, (inverse) transform, output 313 Reconstructed residual block 314 Reconstruction unit, adder, summer 315 Reconstructed block 320 Loop filter, loop filter unit, loop filtering unit 321 Filtered block, decoded video block 330 Decoded picture buffer (DPB), decoded picture buffer (DBP) 331 Decoded picture 344 Inter prediction unit 354 Intra prediction unit, intra prediction 360 Mode selection unit 362 Partitioning 365 Prediction block 400 Video coding device 410 Incoming port, input port 420 Receiver unit (Rx) 430 Processor, logic unit, central processing unit (CPU) 440 Transmitter unit (Tx) 450 Transmission port, output port 460 Memory 470 Coding module 500 Device 502 Processor 504 Memory 506 Data 508 Operating system 510 Application program 512 Bus 514 Secondary storage 518 Display 700 Current block 900 CTU 1300 Construction method 1400 Method 1600 Device 1601 HMI list acquisition unit 1603 HMI list update unit 1700 Inter-prediction device 1701 List management unit 1703 Information derivation unit 3100 Content supply system 3102 Capture device 3104 Communication link 3106 Terminal device 3108 Smartphone, smart pad 3110 Computer, laptop 3112 Network video recorder (NVR) / Digital video recorder (DVR) 3114 TV 3116 Set-top box (STB) 3118 Video conferencing system 3120 Video surveillance system 3122 Personal digital assistant (PDA) 3124 In-vehicle device 3126 Display 3202 Protocol Progress Unit 3204 Demultiplexing Unit 3206 Video Decoder 3208 Audio Decoder 3210 Subtitle Decoder 3212 Synchronization Unit 3214 Video / Audio Display 3216 Video / Audio / Subtitle Display

Claims

1. A method for decoding a block within a frame of a video signal, comprising: analyzing a bitstream to obtain a reconstructed residual block; A step of constructing a list of motion information candidates based on a history, wherein the list of motion information candidates based on the history includes N pieces of motion information candidates H based on the history of N preceding blocks that precede the block k is an ordered list including, where k = 0, ..., N - 1, N is an integer greater than 0, the N preceding blocks are from the same frame as the block, the N preceding blocks include non-adjacent blocks to the block, the list of motion information candidates based on the history has a length of N, N is 5, and each motion information candidate based on the history is an element, that is, i) one or more motion vectors (MVs), ii) one or more reference picture indices corresponding to the MVs, and iii) an interpolation filter index including steps; adding one or more history-based motion information candidates from a history-based motion information candidate list to a motion information candidate list for the block; deriving motion information for the block based on the motion information candidate list; when at least one of the one or more motion vectors (MVs) included in the derived motion information points to a half-sample position, obtaining predicted sample values for the block by applying a half-sample interpolation filter to sample values of a reference picture pointed to by the MV, wherein the half-sample interpolation filter is indicated by a half-sample interpolation filter index included in the derived motion information, and the reference picture is indicated by the one or more reference picture indices included in the derived motion information; obtaining a reconstructed block based on the reconstructed residual block and a predicted block including the predicted sample values; A method comprising.

2. The method according to claim 1, wherein an alternative half-sample interpolation filter is applied only when at least one of the one or more MVs of the derived motion information points to a half-sample position, and the alternative half-sample interpolation filter is indicated by an interpolation filter index included in the derived motion information.

3. The method according to claim 1, wherein the interpolation filter index included in the history-based motion information candidate indicates a half-sample interpolation filter among a set of half-sample interpolation filters, and the half-sample interpolation filter is applied to interpolate half-sample values only when at least one of the one or more MVs of the history-based motion information candidate points to a half-sample position.

4. The following elements of each history-based motion information candidate in the history-based motion information candidate list, namely: i) the one or more motion vectors (MVs), and ii) the one or more reference picture indexes corresponding to the one or more MVs If at least one of them is different from the corresponding element of the motion information of the block, the motion information candidate H based on the history including the motion information of the block is included in the motion information candidate list based on the history k The method according to any one of claims 1 to 3, further comprising the step of adding k , where k = N.

5. the following elements of the history-based motion information candidate of the history-based motion information candidate list, namely, i) one or more motion vectors (MVs), and ii) the one or more reference picture indexes corresponding to the MVs If it is the same as the corresponding element of the movement information of the block, delete the movement information candidate based on the history from the movement information candidate list based on the history, and include the movement information of the block in the movement information candidate list based on the history. Add the movement information candidate H based on the history k The method according to any one of claims 1 to 3, further comprising the step of adding, wherein k = N-1

6. If N is equal to a predefined number, delete the history-based motion information candidate H where k = 0 from the list of history-based motion information candidate, and add the motion information of the block as the history-based motion information candidate H where k = N - 1 to the list of history-based motion information candidate k The method according to any one of claims 1 to 5, further comprising the step of k adding as

7. a step of comparing whether the motion vector of the history-based motion information candidate in the history-based motion information candidate list is the same as the corresponding motion vector of the block; a step of comparing whether the reference picture index of the history-based motion information candidate is the same as the corresponding reference picture index of the block; The method according to claim 4 or 5, further comprising the steps of:

8. a step of comparing whether at least one of the motion vectors of each history-based motion information candidate is different from the corresponding motion vector of the block; a step of comparing whether at least one of the reference picture indexes of each HMVP candidate is different from the corresponding reference picture index of the block; The method according to claim 4 or 5, further comprising the steps of:

9. The method according to any one of claims 1 to 8, wherein the motion information candidate list is used for merge mode or skip mode.

10. The step of deriving the motion information for the block based on the motion information candidate list, The method according to any one of claims 1 to 9, comprising the step of deriving the motion information referred to by the candidate index from the motion information candidate list as the motion information of the current block.

11. A decoder (20) comprising a processing circuit for executing the method according to any one of claims 1 to 10.

12. A method for encoding a block within a frame of a video signal, comprising: A step of constructing a list of motion information candidates based on history, wherein the list of motion information candidates based on history includes N pieces of motion information candidates based on history H including the motion information of N preceding blocks preceding the block k is an ordered list including, where k = 0, ..., N - 1, N is an integer greater than 0, the N preceding blocks are from the same frame as the block, the N preceding blocks include non-adjacent blocks to the block, the list of motion information candidates based on history has a length of N, N is 5, and each motion information candidate based on history is an element, that is iv) one or more motion vectors (MVs), v) the one or more reference picture indexes corresponding to the MVs, and vi) an interpolation filter index including the steps of: adding one or more history-based motion information candidates from the history-based motion information candidate list to the motion information candidate list for the block; A step of deriving motion information for the block based on the motion information candidate list; A step of obtaining a predicted sample value of the block by applying a half-sample interpolation filter to a sample value of a reference picture pointed to by the MV when at least one of one or more motion vectors (MVs) included in the derived motion information points to a half-sample position, wherein the half-sample interpolation filter is indicated by a half-sample interpolation filter index included in the derived motion information, and the reference picture is indicated by the one or more reference picture indexes included in the derived motion information; A step of obtaining a residual block based on the block and a predicted block including the predicted sample value; A step of encoding the residual block into a bit stream; A method including the above steps.

13. The method according to claim 12, wherein an alternative half-sample interpolation filter is applied only when at least one of one or more MVs of the derived motion information points to a half-sample position, and the alternative half-sample interpolation filter is indicated by an interpolation filter index included in the derived motion information.

14. The method according to claim 12, wherein the interpolation filter index included in the motion information candidate based on the history indicates a half-sample interpolation filter among a set of half-sample interpolation filters, and the half-sample interpolation filter is applied to interpolate half-sample values only when at least one of the one or more MVs of the motion information candidate based on the history points to a half-sample position.

15. The following elements of each motion information candidate based on the history in the motion information candidate list based on the history, namely: iii) The one or more motion vectors (MVs), and iv) The one or more reference picture indexes corresponding to the one or more MVs If at least one of them is different from the corresponding element of the motion information of the block, add the history-based motion information candidate H including the motion information of the block to the history-based motion information candidate list k The method according to any one of claims 12 to 14, further comprising the step of adding, where k = N

16. The following elements of the motion information candidate based on the history in the motion information candidate list based on the history, namely: iii) One or more motion vectors (MVs), and iv) The one or more reference picture indexes corresponding to the MVs If it is the same as the corresponding element of the movement information of the block, delete the movement information candidate based on the history from the movement information candidate list based on the history, and include the movement information of the block in the movement information candidate list based on the history. Add the movement information candidate H based on the history k The method according to any one of claims 12 to 14, further comprising the step of adding, where k = N - 1

17. If N is equal to a predefined number, delete the movement information candidate H based on the history where k = 0 from the list of movement information candidates based on the history k and add the movement information of the block as the movement information candidate H based on the history where k = N - 1 to the list of movement information candidates based on the history k The method according to any one of claims 12 to 16, further comprising the step of adding.

18. A step of comparing whether the motion vector of the motion information candidate based on the history in the motion information candidate list based on the history is the same as the corresponding motion vector of the block; A step of comparing whether the reference picture index of the motion information candidate based on the history is the same as the corresponding reference picture index of the block; The method according to claim 15 or 16, further comprising:

19. A step of comparing whether at least one of the motion vectors of the motion information candidates based on each history is different from the corresponding motion vector of the block; A step of comparing whether at least one of the reference picture indexes of each HMVP candidate is different from the corresponding reference picture index of the block; The method according to claim 15 or 16, further comprising:

20. The method according to any one of claims 12 to 19, wherein the motion information candidate list is used for the merge mode or the skip mode.

21. The step of deriving the motion information for the block based on the motion information candidate list The method according to any one of claims 12 to 20, comprising a step of deriving, as the motion information of the current block, the motion information referred to by the candidate index from the motion information candidate list.

22. An encoder (30) including a processing circuit for executing the method according to any one of claims 12 to 21.

23. A method for storing a bitstream, comprising: A step of generating a bitstream by the method according to any one of claims 12 to 21; A step of storing the bitstream in one or more storage media; The method comprising:

24. A method for transmitting a bitstream, comprising: A step of generating at least one bitstream by the method according to any one of claims 12 to 21; A step of storing the at least one bitstream in at least one storage media; A step of obtaining one or more bitstreams from one of the at least one storage media; A step of transmitting the one or more bitstreams to a destination device; The method comprising:

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