RU2775829C1 - Method and apparatus for encoding/decoding an image and record medium storing a bitstream - Google Patents

Abstract

FIELD: encoding.

SUBSTANCE: group of inventions relates to the technology for encoding/decoding images utilising a list of motion information storing previously retrieved motion information. Proposed is a method for generating a list of motion information candidates, generated when decoding an image. The method includes a stage of generating a list of candidates, including motion information generated using the information of a neighbouring block adjacent to the current block. The motion information of the current block is then output using the list of candidates. A prediction block of the current block is generated using the output second motion information of the current block. The list of motion information is also updated in order to store the output motion information of the current block. The list of candidates therein includes at least one of the motion information included in the list of motion information used for the block decoded prior to decoding for the current block.

EFFECT: increase in the efficiency of image compression utilising a list of motion information.

20 cl, 27 dwg

Description

Technical field

[0001] The present invention relates to a method and apparatus for encoding/decoding an image and a recording medium for storing a bit stream. More specifically, the present invention relates to a method and apparatus for encoding/decoding an image that uses a motion information list storing previously recovered motion information.

Prior Art

[0002] Recently, the demand for high resolution and high quality images such as high definition (HD) images and ultra high definition (UHD) images has increased in various applications. As the resolution and quality of image data increases, the amount of data increases compared to conventional image data. Therefore, when image data is transmitted using a medium such as a conventional wired/wireless broadband channel or stored using a known storage medium, the transmission and storage costs increase. In order to solve these problems caused by increasing the resolution and quality of image data, a highly efficient image encoding/decoding method for an image having high resolution and quality is required.

[0003] As an image compression method, there are various methods such as an inter-prediction method for predicting pixel values included in the current picture from a picture before or after the current picture; an intra prediction method for predicting pixel values included in the current picture using the pixel information in the current picture; a transformation and quantization method for compressing the energy of the residual signal; and an entropy encoding method for extracting a short code for a value with a high occurrence frequency and a long code for a value with a low occurrence frequency. Such image compression techniques can be used to efficiently compress and transmit or store image data.

Disclosure

Technical task

[0004] It is an object of the present invention to provide a method and apparatus for encoding and decoding an image and a recording medium storing a bitstream that improve compression efficiency using a motion information list storing previously recovered motion information.

TECHNICAL SOLUTION

[0005] An image decoding method according to an embodiment of the present invention, the method may comprise generating a candidate list including motion information derived from a spatial neighbor block and a temporal neighbor block adjacent to the current block, deriving the motion information of the current block using the list candidates, generating a prediction block of the current block using the derived motion information, updating the derived motion information in the motion information list, wherein the generation of the candidate list is performed to include at least one of the motion information included in the updated motion information list in the block, which decoded before the current block.

[0006] In the image decoding method according to the present invention, the motion information list is initialized when decoding of a predetermined area is completed, so that the area is changed.

[0007] In the image decoding method according to the present invention, the predefined area is any one of a block composed of one or more coding units (CUs) or a block composed of one or more coding tree units (CTUs).

[0008] In the image decoding method according to the present invention, when there is a plurality of motion information in the updated motion information list in a block decoded before the current block, generation of the candidate list is performed so as to include an average of at least two or more motion information from a set of traffic information in the list of candidates.

[0009] In the image decoding method according to the present invention, when the motion information of the updated motion information list in the block decoded before the current block is the same as the motion information previously included in the candidate list, generation of the candidate list is performed as follows to not include the movement information of the movement information list in the list of candidates.

[0010] In the image decoding method according to the present invention, when the current block is the IBC prediction mode and the candidate list is the shared merge list, updating the outputted motion information in the motion information list is omitted.

[0011] In the image decoding method according to the present invention, the motion information list has a predetermined size limitation.

[0012] In the image decoding method according to the present invention, when the amount of motion information stored in the motion information list is a predetermined value, updating the output motion information in the motion information list includes deleting the motion information stored first in the motion information list , and storing the derived motion information.

[0013] A method for encoding an image according to an embodiment of the present invention, the method may comprise generating a candidate list including motion information derived from a spatial neighbor block and a temporal neighbor block adjacent to the current block, deriving the motion information of the current block using a candidate list, generating a prediction block of the current block using the derived motion information, updating the derived motion information in the motion information list, and wherein generating the candidate list is performed to include at least one of the motion information included in the updated motion information list in the block The that is encoded before the current block.

[0014] In the image encoding method according to the present invention, the motion information list is initialized when encoding of a predetermined area is completed, so that the area is changed.

[0015] In the image encoding method according to the present invention, the predefined area is any one of one or more coding tree units (CUs) or one or more coding tree units (CTUs).

[0016] In the picture encoding method according to the present invention, when there are a plurality of motion information in the updated motion information list in a block encoded before the current block, generation of the candidate list is performed to include an average of at least two or more motion information from a set of traffic information in the list of candidates.

[0017] In the picture encoding method according to the present invention, when the motion information of the updated motion information list in the block encoded before the current block is the same as the motion information previously included in the candidate list, generation of the candidate list is performed as follows to not include the movement information of the movement information list in the list of candidates.

[0018] In the image encoding method according to the present invention, when the current block is the IBC prediction mode and the candidate list is the shared merge list, updating the outputted motion information in the motion information list is omitted.

[0019] In the image encoding method according to the present invention, the motion information list has a predetermined size limitation.

[0020] In the image encoding method according to the present invention, when the amount of motion information stored in the motion information list is a predetermined value, updating the output motion information in the motion information list includes deleting the motion information stored first in the motion information list , and storing the derived motion information.

[0021] In a long-term computer-readable recording medium comprising a bitstream decoded by the image decoding method according to an embodiment of the present invention, the image decoding method may comprise generating a candidate list including motion information derived from a spatial neighbor block and a temporal neighbor block adjacent to the current block, deriving motion information of the current block using the candidate list, generating a prediction block of the current block using the derived motion information, updating the derived motion information in the motion information list, and wherein generating the candidate list is performed to include at least one information from the motion information included in the updated motion information list in the block decoded before the current block.

USEFUL RESULTS

[0022] The present invention can provide a method and apparatus for encoding and decoding an image and a recording medium storing a bitstream that improve compression efficiency using a motion information list storing previously recovered motion information.

[0023] According to the present invention, when there is little motion information or no motion information in the motion information list storing previously recovered motion information, the prediction information can be stored in the motion information list and used to more accurately perform inter-prediction.

[0024] According to the present invention, the coding and decoding efficiency of an image can be improved.

[0025] In accordance with the present invention, the computational complexity of the image encoder and decoder can be reduced.

DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a block diagram illustrating the configuration of an encoder according to an embodiment of the present invention.

[0027] FIG. 2 is a block diagram illustrating the configuration of a decoding apparatus according to an embodiment of the present invention.

[0028] FIG. 3 is a diagram schematically illustrating an image partition structure in image encoding and decoding.

[0029] FIG. 4 is a diagram illustrating an embodiment of an intra-prediction process.

[0030] FIG. 5 is a diagram illustrating an embodiment of an inter-prediction process.

[0031] FIG. 6 is a diagram illustrating the conversion and quantization process.

[0032] FIG. 7 is a diagram illustrating the reference samples available for intra prediction.

[0033] FIG. 8 and 9 are diagrams illustrating an encoder and a decoder using a motion information list.

[0034] FIG. 10 is a flowchart illustrating an inter prediction method using a motion information list according to the present invention.

[0035] FIG. 11 is a flowchart illustrating an inter prediction method using a motion information list.

[0036] FIG. 12 is a flowchart illustrating an inter prediction method in which motion information list prediction is performed at a motion information list initialization time and a motion information addition time.

[0037] FIG. 13 and 14 are diagrams illustrating an encoder and a decoder including a motion information list predictor.

[0038] FIG. 15 is a diagram illustrating an embodiment of signaling including a pointer indicating whether to apply a motion information list to sequence parameter set (SPS) syntax.

[0039] FIG. 16 is a diagram illustrating an embodiment of signaling including a pointer indicating whether to apply a motion information list to a picture parameter set (PPS) syntax.

[0040] FIG. 17 is a diagram illustrating an embodiment of signaling including a pointer indicating whether to apply the motion information list to the slice header syntax.

[0041] FIG. 18 is a diagram illustrating an example of motion information prediction of the current motion information list from an area adjacent in time to the current block.

[0042] FIG. 19 is a diagram illustrating an example of motion information prediction of the current motion information list from an area spatially adjacent to the current coding block.

[0043] FIG. 20 is a diagram illustrating an example of a method for performing prediction of the current motion information list with reference to the motion information list of the previously recovered UPU.

[0044] FIG. 21 is a diagram illustrating a method for performing motion information list prediction from motion information stored in the current motion information list.

[0045] FIG. 22 is a diagram illustrating an example of a prediction motion information derivation process by changing the reference picture of the existing motion information and adjusting the motion vector accordingly.

[0046] FIG. 23 is a diagram illustrating a motion information list prediction method that does not overlap with a motion prediction method candidate.

[0047] FIG. 24 is a diagram illustrating an embodiment of setting a position that is a reference for motion information list prediction in a CTU when the position of a temporal candidate of the motion prediction method is the same as positions C and H in FIG. 23.

[0048] FIG. 25 and 26 are diagrams illustrating an embodiment of a method for using predicted motion information and common motion information separately.

[0049] FIG. 27 is a flowchart illustrating an image decoding method according to an embodiment of the present invention.

MODE OF CARRYING OUT THE INVENTION

[0050] Many modifications can be made to the present invention, and there are various embodiments of the present invention, examples of which will be presented below and described in detail with reference to the drawings. However, the present invention is not limited thereto, although the exemplary embodiments may be construed as including all modifications, equivalents, or substitutions within the technical principle and scope of the present invention. Like reference numerals refer to the same or similar functions in various aspects. In the drawings, the shapes and sizes of elements may be exaggerated for clarity. In the following detailed description of the present invention, reference is made to the accompanying drawings which show, by way of illustration, specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to implement the present disclosure. The numerous embodiments of the present disclosure, while varied, are not necessarily mutually exclusive. For example, specific features, structures, and characteristics described herein in connection with one embodiment may be implemented in other embodiments without departing from the spirit and scope of the present disclosure. In addition, it should be clear that the location or layout of the individual elements in each disclosed embodiment can be modified without deviating from the spirit and scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present disclosure is only defined by the appended claims, properly interpreted, together with the full range of equivalents of what is claimed in the claims.

[0051] As used in the specification, the terms 'first', 'second', etc. may be used to describe various components, but components should not be meant to be limited by these terms. These terms are only used to distinguish one component from other components. For example, the 'first' component may be referred to as the 'second' component without deviating from the scope of the present invention, and the 'second' component may also be referred to as the 'first' component in the same way. The term ‘and/or’ includes a combination of a plurality of elements or any one of a plurality of members.

[0052] It should be understood that when an element is simply referred to as 'connected to' or 'connected to' another element without being 'directly connected to' or 'directly connected to' another element in the present description, it may be 'directly connected to ' or 'directly related to' another element, or be connected or related to another element, having another element intermediate between them. On the contrary, it should be understood that when an element is referred to as "directly connected" or "directly connected" to another element, there are no intermediate elements.

[0053] In addition, the constituent parts shown in the embodiments of the present invention are shown independently to represent characteristic functions that differ from each other. Thus, it does not mean that each sub-part is contained within a sub-unit of separate hardware or software. In other words, each sub-part includes each of the numbered sub-parts, for convenience. Thus, at least two constituent parts of each constituent part may be combined to form one constituent part, or one constituent part may be divided into a plurality of constituent parts to perform each function. The embodiment where each component is combined and the embodiment where one component is separated are also included in the scope of the present invention, if this does not deviate from the essence of the present invention.

[0054] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the present invention. An expression used in the singular includes a plural expression, unless it has a distinctly different meaning in the context. In this specification, it should be understood that terms such as "comprising", "having", etc., are intended to indicate the presence of the features, quantities, steps, acts, elements, parts, or combinations thereof disclosed in the specification. , should not exclude the possibility that one or more other features, quantities, steps, acts, elements, parts, or combinations thereof may exist or may be added. In other words, when a particular element is referred to as “included”, elements other than the corresponding element are not excluded, but additional elements may be included in embodiments of the present invention or the scope of the present invention.

[0055] In addition, some of the components may not be necessary components that perform the essential functions of the present invention, but are specific components that only improve its performance. The present invention can be implemented by including only the necessary components to implement the essence of the present invention, excluding components used to improve performance. A structure that includes only the necessary components, excluding specific components used only to improve performance, is also included in the scope of the present invention.

[0056] Further, embodiments of the present invention will be described in detail with reference to the attached drawings. In describing exemplary embodiments of the present invention, well-known functions or constructions will not be described in detail as they could unnecessarily complicate the understanding of the present invention. Like components in the drawings are designated by the same reference numerals, and repeated description of the same elements will be omitted.

[0057] Further, the image may mean a picture configuring the video, or may mean the video itself. For example, “encoding or decoding or both of a picture” may mean “encoding or decoding or both of a moving picture” and may mean “encoding or decoding or both of a single picture among moving picture pictures”.

[0058] Further, the terms "moving picture" and "video" can be used as having the same meaning and can be interchanged.

[0059] Further, the target image may be an encoding target image that is an encoding target and/or a decoding target image that is a decoding target. Also, the target image may be an input image input to the encoding device and an input image input to the decoding device. Here, the target image can have the same value as the current image.

[0060] Further, the terms "image", "picture", "frame" and "screen" can be used as having the same meaning and replace each other.

[0061] Further, the target block may be an encoding target that is an encoding target and/or a decoding target that is a decoding target. Also, the target block may be the current block, which is the target of the current encoding and/or decoding. For example, the terms "target block" and "current block" can be used as having the same meaning and interchangeable.

[0062] Further, the terms "block" and "unit" can be used as having the same meaning and replace each other. Or a "block" could represent a specific unit.

[0063] Further, the terms "region" and "segment" can be used interchangeably.

[0064] Further, the specific signal may be a signal representing a specific block. For example, the source signal may be a signal representing the target block. The prediction signal may be a signal representing a prediction block. The residual signal may be a signal representing the residual block.

[0065] In embodiments, each of the specific information, data, flag, index, element, and attribute, etc. may matter. An information, data, flag, index, element, and attribute value of "0" may represent a logical "false" or the first predefined value. In other words, the value "0", "false", the logical "false" and the first predefined value can be interchanged. An information, data, flag, index, element, and attribute value of "1" may represent a logical "true" or a second predefined value. In other words, the value "1", "true", the logical "true" and the second predefined value can be interchanged.

[0066] When a variable i or j is used to represent a column, row, or index, the value of i can be an integer equal to or greater than 0, or equal to or greater than 1. That is, column, row, index, etc. . may be 0-based or may be 1-based.

[0067]

[0068] Description of terms

[0069] Encoder: means a device that performs encoding. That is, means encoding device.

[0070] Decoder: means a device that performs decoding. That is, means a decoding device.

[0071] Block: is an M×N sample array. Here, M and N can mean positive integers, and block can mean a two-dimensional sample array. A block can refer to a unit. The current block may mean a target encoding block that becomes a target when encoding, or a target decoding block that becomes a target when decoding. In addition, the current block may be at least one of a coding block, a prediction block, a residual block, and a transform block.

[0072] Sample: is the basic unit that forms the block. It can be expressed as a value from 0 to 2 ^Bd-1 according to the bit depth (Bd). In the present invention, a sample may be used as a pixel designator. That is, sample, image element, pixel can have the same value.

[0073] Unit: may refer to a unit of encoding and decoding. When encoding and decoding an image, a unit may be an area generated by splitting one image. In addition, one may mean a subdivided unit when one picture is divided into subdivided units during encoding or decoding. That is, the image can be divided into many units. When encoding and decoding an image, a predetermined process may be performed for each unit. One unit may be broken down into sub-units that are smaller than the size of the unit. Depending on the functions, a unit may mean a block, a macroblock, a coding tree unit, a coding tree block, a coding unit, a coding block, a prediction unit, a prediction unit, a residual unit, a residual block, a transformation unit, a transformation block, and so on. In addition, to distinguish a unit from a block, the unit may include a luminance component block, a chrominance component block associated with a luma component block, and a syntax element of each color component block. The unit may have various sizes and shapes, in particular, the shape of the unit may be a two-dimensional geometric figure such as a square shape, a rectangular shape, a trapezoid shape, a triangular shape, a pentagonal shape, and so on. In addition, the unit information may include at least one of a unit type indicating a coding unit, a prediction unit, a transformation unit, etc., and a unit size, a unit depth, a unit encoding and decoding sequence, etc.

[0074] Coding tree unit: configured with one luma Y component coding tree block and two coding tree blocks related to Cb and Cr chrominance components. It may also mean that blocks and the syntax element of each block are included. Each coding tree unit may be subdivided using at least one of a quadtree partitioning method, a binary tree partitioning method, and a ternary tree partitioning method to configure a lower unit such as a coding unit, a prediction unit, a transformation unit, and so on. This can be used as a term for a sample block that becomes a processing unit when an image is encoded/decoded as an input image. Here, quadtree can mean quaternary tree.

[0075] When the coding block size is within a predetermined range, division is possible using only quadtree splitting. Here, the predetermined range may be defined as at least one of a maximum size and a minimum size of a coding block in which partitioning is possible using only quadtree partitioning. Information indicating the maximum/minimum size of a coding block in which quadtree splitting is allowed may be signaled by a bitstream, and information may be signaled in at least one sequence unit, picture parameter, tile group, or slice (segment). Alternatively, the maximum/minimum coding block size may be a fixed size predetermined in the encoder/decoder. For example, when the coding block size is from 256x256 to 64x64, division is only possible using quadtree splitting. Alternatively, when the coding block size is larger than the maximum transform block size, partitioning is only possible using quadtree partitioning. Here, the block to be divided may be at least one of an encoding block and a transformation block. In this case, the information indicating splitting of the encoded block (eg, split_flag) may be a flag indicating whether or not to perform quadtree splitting. When the coding block size falls within a predetermined range, splitting is only possible using binary tree splitting or ternary tree splitting. In this case, the above description of quadtree splitting can be applied to binary tree splitting or ternary tree splitting in the same way.

[0076] Coding tree block: can be used as a term to refer to any one of Y coding tree block, Cb coding tree block, and Cr coding tree block.

[0077] Adjacent block: may mean a block adjacent to the current block. A box adjacent to the current box may mean a box that is in contact with the boundary of the current box, or a box positioned within a predetermined distance from the current box. Adjacent block may mean a block adjacent to the top of the current block. Here, the box adjacent to the top of the current box may mean a box vertically adjacent to an adjacent box that is horizontally adjacent to the current box, or a box horizontally adjacent to a neighboring box that is vertically adjacent to the current box.

[0078] Recovered adjacent block: may mean a neighboring block adjacent to the current block and which has already been spatially/temporally encoded or decoded. Here, a recovered neighbor block may mean a recovered neighbor unit. The recovered spatial neighbor block may be a block within the current picture that has already been recovered by encoding or decoding or both. The reconstructed temporal neighbor block is a block at a corresponding position as the current block of the current picture within the reference picture or its neighbor block.

[0079] Depth of the unit: may mean the degree of partitioning of the unit. In a tree structure, the highest node (the root node) may correspond to the first unit that is not split. Also, the highest node can have the smallest depth value. In this case, the highest node may have a level depth of 0. A node having a level depth of 1 may represent a unit generated by splitting the first unit once. A node having a level depth of 2 may represent a unit generated by splitting the first unit twice. A node having a level depth of n may represent a unit generated by splitting the first unit n times. A leaf node can be the lowest node and a node that cannot be further split. The depth of the leaf node can correspond to the maximum level. For example, the predefined maximum level value may be 3. The depth of the root node may be the lowest, and the depth of the leaf node may be the deepest. In addition, when a unit is expressed as a tree structure, the level at which the unit is present may indicate the depth of the unit.

[0080] Bitstream: may mean a bitstream including image encoding information.

[0081] Parameter set: corresponds to the header information among the configuration in the bitstream. At least one of a video parameter set, a sequence parameter set, a picture parameter set, and an adaptation parameter set may be included in the parameter set. In addition, the parameter set may include a slice header, a tile group header, and tile header information. The term "tile group" means a group of tiles and has the same meaning as a slice.

[0082] Parsing: may refer to determining the meaning of a syntax element by performing entropy decoding, or may refer to entropy decoding itself.

[0083] Character: may mean at least one of a syntax element, an encoding parameter, and a transform coefficient value of an encoding/decoding target unit. In addition, the symbol may mean the target of entropy encoding or the result of entropy decoding.

[0084] Prediction mode: may be information indicating an intra-prediction encoded/decoded mode or an inter-prediction encoded/decoded mode.

[0085] Prediction unit: may mean a base unit when performing prediction such as inter prediction, intra prediction, inter (mutual) compensation, intra (internal) compensation, and motion compensation. One prediction unit may be split into multiple smaller partitions, or may be split into multiple smaller prediction units. The set of partitions may be the basic unit when performing prediction or compensation. The partition that is generated by dividing the prediction unit may also be the prediction unit.

[0086] Split prediction unit: may mean a shape obtained by splitting a prediction unit.

[0087] Reference picture list: may refer to a list including one or more reference pictures used for inter-prediction or motion compensation. There are several types of reference picture lists used, including LC (combined list), L0 (list 0), L1 (list 1), L2 (list 2), L3 (list 3).

[0088] Inter-prediction pointer: may refer to the direction of inter-prediction (unidirectional prediction, bidirectional prediction, etc.) of the current block. Alternatively, it may refer to the number of reference pictures used to generate the prediction block of the current block. Alternatively, it may refer to the number of prediction blocks used while performing inter-prediction or motion compensation on the current block.

[0089] Prediction list use flag: indicates whether a prediction block is generated using at least one reference picture in a particular reference picture list. The inter-prediction pointer may be derived using the prediction list use flag, and vice versa, the prediction list use flag may be derived using the inter-prediction pointer. For example, when the prediction list use flag has a first value of zero (0), it means that the reference picture in the reference picture list is not used to generate a prediction block. On the other hand, when the prediction list use flag has a second value of one (1), it means that the reference picture list is used to generate a prediction block.

[0090] Reference picture index: may refer to an index indicating a particular reference picture in the reference picture list.

[0091] Reference picture: may mean a reference picture referenced by a particular block for purposes of inter-prediction or motion compensation of a particular block. Alternatively, the reference picture may be a picture including a reference block referenced by the current block for inter-prediction or motion compensation. Further, the terms "reference picture" and "reference picture" have the same meaning and can be used interchangeably.

[0092] Motion vector: may be a two-dimensional vector used for inter-prediction or motion compensation. The motion vector may mean an offset between an encoding/decoding target block and a reference block. For example, (mvX, mvY) could represent a motion vector. Here, mvX may represent a horizontal component and mvY may represent a vertical component.

[0093] Search range: may be a two-dimensional area in which a search is performed to extract a motion vector during inter-prediction. For example, the size of the search range may be M×N. Here, M and N are both integers.

[0094] Motion vector candidate: may refer to a prediction candidate block or a motion vector of a prediction candidate block in motion vector prediction. In addition, the motion vector candidate may be included in the list of motion vector candidates.

[0095] Motion vector candidate list: may mean a list composed of one or more motion vector candidates.

[0096] Motion vector candidate index: may mean a pointer indicating a motion vector candidate in the list of motion vector candidates. Alternatively, it may be an index of the motion vector predictor.

[0097] Motion information: may mean information including at least one of a motion vector, a reference picture index, an inter-prediction pointer, a prediction list use flag, reference picture list information, a reference picture, a motion vector candidate, a motion vector candidate index, a merge candidate, and a merge index.

[0098] Merge candidate list: may mean a list composed of one or more merge candidates.

[0099] Merge candidate: can mean a spatial merge candidate, a temporal merge candidate, a joint merge candidate, a joint bi-predictive merge candidate, or a null merge candidate. The merge candidate may include motion information such as an inter prediction indicator, a reference picture index for each list, a motion vector, a prediction list usage flag, and an inter prediction indicator.

[00100] Merge index: may mean a pointer indicating a merge candidate in the list of merge candidates. Alternatively, the merge index may indicate the block from which the merge candidate was derived, among the reconstructed blocks spatially/temporally adjacent to the current block. Alternatively, the merge index may indicate at least one piece of merge candidate movement information.

[00101] Transform unit: may mean a base unit when performing encoding/decoding such as transform, inverse transform, quantization, dequantization, encoding/decoding of residual signal transform coefficients. One transformation unit may be broken down into multiple lower level transformation units having a smaller size. Here, the transform/inverse transform may comprise at least one of the first transform/first inverse transform and the second transform/second inverse transform.

[00102] Scaling: may refer to the process of multiplying a quantized level by a factor. The transform coefficient may be generated by scaling the quantized level. Scaling may also be referred to as dequantization.

[00103] Quantization parameter: may mean a value used when generating a quantized level using a quantization transform coefficient. The quantization parameter may also mean a value used in generating the transform coefficient by scaling the quantized level in dequantization. The quantization parameter may be a value mapped to the quantization step size.

[00104] Delta quantization parameter: may mean a difference between the predicted quantization parameter and the quantization parameter of the target coding/decoding unit.

[00105] Scanning: can mean a way of ordering coefficients within a unit, block, or matrix. For example, a transition from a two-dimensional coefficient matrix to a one-dimensional matrix may be referred to as a scan, and a transition from a one-dimensional coefficient matrix to a two-dimensional matrix may be referred to as a scan or inverse scan.

[00106] Transform Coefficient: may refer to a coefficient value generated after performing a transform in an encoder. It may mean a coefficient value generated after performing at least one of entropy decoding and dequantization in a decoder. The quantized level obtained by quantizing the transform coefficient or the residual signal, or the level of the quantized transform coefficient may also be covered by the meaning of the transform coefficient.

[00107] Quantized level: may mean a value generated by quantizing a transform coefficient or residual signal in an encoder. Alternatively, the quantized level may mean a value that is the target of dequantization for performing dequantization at the decoder. Similarly, the level of the quantized transform coefficient, which is the result of the transformation and quantization, may also be covered by the semantic value of the quantized level.

[00108] Non-zero transform coefficient: may mean a transform coefficient having a value other than zero, or a transform coefficient level or a quantized level having a value other than zero.

[00109] Quantization matrix: may mean a matrix used in a quantization process or a dequantization process performed to improve subjective or objective image quality. The quantization matrix may also be referred to as a scaling list.

[00110] Quantization matrix coefficient: may mean each element in the quantization matrix. The coefficient of the quantization matrix may also be referred to as the coefficient of the matrix.

[00111] Default matrix: may mean a predefined quantization matrix predefined in the encoder or decoder.

[00112] Non-default matrix: may mean a quantization matrix that is not predefined in the encoder or decoder, but signaled by the user.

[00113] Statistic value: the statistic value for at least one of a variable, an encoding parameter, a constant value, etc., which have a specific value calculated, may be one or more of an average value, a sum value, a weighted average, a weighted total value, minimum value, maximum value, most frequent value, median value, interpolated value of the corresponding particular value.

[00114] FIG. 1 is a block diagram showing the configuration of an encoding apparatus according to an embodiment to which the present invention is applicable.

[00115] The encoding device 100 may be an encoder, a video encoding device, or an image encoding device. The video may include at least one image. Encoder 100 may sequentially encode at least one picture.

[00116] With reference to FIG. 1, the encoding device 100 may include a motion prediction module 111, a motion compensation module 112, an intra prediction module 120, a switch 115, a subtractor 125, a transform module 130, a quantization module 140, an entropy encoding module 150, a dequantization module 160, a module 170 inverse transform, adder 175, filter module 180, and reference picture buffer 190.

[00117] Encoder 100 may encode an input image using intra mode or inter mode, or both. In addition, the encoding apparatus 100 can generate a bitstream including encoded information by encoding an input image and output the generated bitstream. The generated bitstream may be stored in a computer-readable recording medium, or may be streamed over a wired/wireless transmission medium. When the intra mode is used as the prediction mode, the switch 115 may switch to the intra mode. Alternatively, when the inter mode is used as the prediction mode, the switch 115 may switch to the inter mode. Here, the intra mode may mean the intra prediction mode, and the inter mode may mean the inter prediction mode. Encoder 100 may generate a prediction block for an input block of an input image. In addition, the encoding apparatus 100 can encode the residual block using the remainder of the input block and the prediction block after generating the prediction block. The input image may be referred to as the current image, which is the current encoding target. An input block may be referred to as a current block, which is the current encoding target, or an encoding target block.

[00118] When the prediction mode is intra mode, intra prediction module 120 may use a sample of a block that has already been coded/decoded and is adjacent to the current block as a reference sample. Intra-prediction module 120 may perform spatial prediction for the current block using a reference sample, or generate input block prediction samples by performing spatial prediction. Here, intra-prediction can mean intra-prediction,

[00119] When the prediction mode is the inter mode, the motion prediction unit 111 can extract an area that best matches the input block from the reference image when performing motion prediction, and output a motion vector using the extracted area. In this case, the search area may be used as said area. The reference picture may be stored in the reference picture buffer 190 . Here, when encoding/decoding for a reference picture is performed, it may be stored in the reference picture buffer 190 .

[00120] The motion compensation unit 112 may generate a prediction block by performing motion compensation for the current block using the motion vector. Here, inter-prediction may mean inter-prediction or motion compensation.

[00121] When the motion vector value is not an integer, the motion prediction module 111 and the motion compensation module 112 may generate a prediction block by applying an interpolation filter to a partial area of the reference picture. In order to perform inter-picture prediction or motion compensation on a coding unit, which mode of skip mode, merge mode, advanced motion vector prediction (AMVP) mode, and current picture reference mode is used for motion prediction and motion compensation of the prediction unit included in corresponding coding unit. Then, inter-picture prediction or motion compensation may be performed differently depending on the specific mode.

[00122] Subtractor 125 may generate a residual block using the difference between the input block and the prediction block. The residual block may be referred to as a residual signal. The residual signal may mean the difference between the original signal and the prediction signal. In addition, the residual signal may be a signal generated by transforming or quantizing or transforming and quantizing a difference between the original signal and the prediction signal. The residual block may be a block unit residual signal.

[00123] The transform unit 130 may generate a transform coefficient by performing a residual block transform, and output the generated transform coefficient. Here, the transform coefficient may be a coefficient value generated by performing a residual block transform. When the conversion skip mode is applied, the conversion unit 130 may skip the conversion of the residual block.

[00124] The quantized level may be generated by applying quantization to the transform coefficient or to the residual signal. Further, the quantized level may also be referred to as a transform coefficient in the embodiments.

[00125] The quantization unit 140 may generate a quantized level by quantizing a transform coefficient or a residual signal according to a parameter, and output the generated quantized level. Here, the quantizer 140 may quantize the transform coefficient using a quantization matrix.

[00126] Entropy encoding unit 150 may generate a bitstream by performing entropy encoding according to a probability distribution over values calculated by quantization unit 140 or over encoding parameter values calculated when encoding is performed, and output the generated bitstream. The entropy encoding unit 150 may perform entropy encoding of image sample information and image decoding information. For example, information for decoding an image may include a syntax element.

[00127] When entropy encoding is applied, symbols are represented such that fewer bits are assigned to a symbol having a high generation probability and more bits are assigned to a symbol having a low generation probability, and thus the bitstream size for the symbols to be encoded , may decrease. The entropy encoding unit 150 may use an encoding method for entropy encoding such as exponential Golomb coding, context adaptive variable length coding (CAVLC), context adaptive binary arithmetic coding (CABAC), and so on. For example, entropy encoding module 150 may perform entropy encoding using a variable length coding/code (VLC) table. In addition, the entropy encoding unit 150 can derive the target symbol binarization method and the target symbol/bin probability model, and perform arithmetic encoding using the derived binarization method and the context model.

[00128] In order to encode a transform coefficient level (quantized level), the entropy encoding unit 150 may convert the coefficient in the form of a two-dimensional block into the form of a one-dimensional vector using a transform coefficient scan method.

[00129] The encoding parameter may include information (flag, index, etc.) such as a syntax element that is encoded in the encoder and signaled to the decoder, and information output when encoding or decoding is performed. The encoding parameter may mean information required when encoding or decoding an image. For example, at least one value or form of combination of unit/block size, unit/block depth, unit/block split information, unit/block shape, unit/block split structure, whether to split in quadtree shape, whether to split in shape of the binary tree, direction of the split the shape of the binary tree (horizontal direction or vertical direction), the shape of the split in the form of the binary tree (symmetric split or asymmetric split), whether the current coding unit is split by splitting the ternary tree, the direction (horizontal or vertical direction) of splitting the ternary tree , the type (symmetric or asymmetric type) of the ternary tree split, whether the current coding unit is split by a set type tree split, the direction (horizontal or vertical direction) of the set type tree split, the type (symmetric or asymmetric type) of the set type tree split, and the tree structure ( binary tree o or ternary tree) split tree of multiple types, prediction mode (intra-prediction or inter-prediction), luma intra-prediction mode/direction, chroma intra-prediction mode/direction, intra-split information, inter-split information, split flag coding block, prediction block split flag, transform block split flag, reference sample filtering method, reference sample filter tap, reference sample filter coefficient, prediction block filtering method, prediction block filter tap, prediction block filter coefficient, prediction block boundary filtering method, tap prediction block boundary filter, prediction block boundary filter coefficient, intra prediction mode, inter prediction mode, motion information, motion vector, motion vector difference, reference picture index, inter prediction angle, inter prediction pointer, prediction list use flag, list of reference of pictures, reference picture, motion vector predictor index, motion vector predictor candidate, motion vector candidate list, whether to use merge mode, merge index, merge candidate, merge candidate list, whether to use skip mode, interpolation filter type, interpolation filter tap, interpolation filter coefficient, motion vector size, motion vector representation precision, transform type, transform size, information whether primary (first) transform is used, information whether secondary transform is used, primary transform index, secondary transform index, information whether residual signal is presented , code block pattern, code block flag (CBF), quantization parameter, quantization parameter remainder, quantization matrix, whether to apply in-loop filter, in-loop filter gain, in-loop filter tap, in-loop shape filter o, whether to apply deblocking filter, deblocking filter coefficient, deblocking filter tap, deblocking filter strength, deblocking filter shape, whether to apply adaptive sampling bias, adaptive sampling bias values, adaptive sampling bias category, adaptive bias type sampling, whether to apply adaptive loop filter, adaptive loop filter coefficient, adaptive loop filter tap, adaptive loop filter shape, binarization/inverse binarization method, context model determination method, context model update method, whether to perform regular mode, whether to perform mode bypass, context bin, bypass bin, significant coefficient flag, last significant coefficient flag, encoded flag for coefficient group unit, position of last significant coefficient, flag for whether coefficient value is large, than 1, a flag for whether the coefficient value is greater than 2, a flag for whether the coefficient value is greater than 3, coefficient residual value information, sign information, recovered luma sample, recovered chrominance sample, residual luminance sample, chrominance residual sampling, luminance transform coefficient, chroma transform coefficient, quantized luma level, quantized chrominance level, transform coefficient level scanning method, decoder-side motion vector search region size, decoder-side motion vector search region shape, number of times of motion vector search at decoder side, CTU size information, minimum block size information, maximum block size information, maximum block depth information, minimum block depth information, picture display/output sequence, slice identification information, slice type, slice, tile identification information, tile type, tile split information, tile group identification information, tile group type, tile group split information, picture type, input sample bit depth, reconstructed sample bit depth, residual sample bit depth , bit depth of the transform coefficient, bit depth of the quantized level, and luma information or chroma information may be included in the coding parameter.

[00130] Here, flag or index signaling may mean that the corresponding flag or index is entropy encoded and included in the bitstream by the encoder, and may mean that the corresponding flag or index is entropy decoded from the bitstream by the decoder.

[00131] When the encoder 100 performs inter-prediction encoding, the encoded current picture can be used as a reference picture for another picture that is processed thereafter. Accordingly, the encoding device 100 may restore or decode the encoded current picture, or store the restored or decoded picture as a reference picture in the reference picture buffer 190 .

[00132] The quantized level may be dequantized in dequantization module 160, or may be inversely transformed in inverse transform module 170. The dequantized and/or inversely transformed coefficient may be added to the prediction block via adder 175. By adding the dequantized and/or inversely transformed coefficient to the prediction block, a reconstructed block may be generated. Here, the dequantized and/or inversely transformed coefficient may mean a coefficient on which at least one of dequantization and inverse transformation has been performed, and may mean a reconstructed residual block.

[00133] The recovered block may pass through the filter module 180. Filter module 180 may apply at least one of a deblocking filter, an adaptive sample offset (SAO), and an adaptive loop filter (ALF) to the reconstructed sample, reconstructed block, or reconstructed image. The filter module 180 may be referred to as a loop filter.

[00134] The deblocking filter can deblock the block distortion generated at the boundaries between blocks. In order to determine whether a deblocking filter should be applied, it may be determined whether a deblocking filter should be applied to the current block based on the samples included in the various rows or columns that are included in the block. When a deblocking filter is applied to a block, a different filter may be applied according to the desired strength (level) of the deblocking filtering.

[00135] In order to compensate for an encoding error, an appropriate bias value may be added to the sample value using an adaptive sample bias. The adaptive sampling bias can correct the bias of the deblocked image relative to the original image per sample unit. A method of dividing the image samples into a predetermined number of areas, determining the area to which the offset is applied, and applying the offset to the determined area, or a method of applying the offset based on edge information on each sample may be used.

[00136] The adaptive edge filter may perform filtering based on a comparison result of the filtered reconstructed image and the original image. The samples included in the image may be divided into predefined groups, a filter may be defined to apply to each group, and differential filtering may be performed for each group. Whether or not ALF should be applied may be signaled by coding units (CUs), and the shape and factor of the ALF to be applied to each block may vary.

[00137] The restored block or restored image, after passing through the filter module 180, may be stored in the reference picture buffer 190. The reconstructed block processed by filter module 180 may be part of a reference image. That is, the reference image is a reconstructed image composed of the reconstructed blocks processed by the filter module 180 . The stored reference image can be used later in inter-prediction or motion compensation.

[00138] FIG. 2 is a block diagram showing a configuration of a decoding apparatus according to an embodiment to which the present invention is applicable.

[00139] The decoding device 200 may be a decoder, a video decoding device, or an image decoding device.

[00140] With reference to FIG. 2, the decoding apparatus 200 may include an entropy decoding unit 210, a dequantization unit 220, an inverse transform unit 230, an intra prediction unit 240, a motion compensation unit 250, an adder 225, a filter unit 260, and a reference picture buffer 270.

[00141] The decoder 200 may receive a bitstream output from the encoder 100. The decoding apparatus 200 may receive a bitstream stored in a computer-readable recording medium, or may receive a bitstream transmitted by streaming via a wired/wireless transmission medium. The decoder 200 may decode the bitstream using intra mode or inter mode. In addition, the decoding apparatus 200 can generate a reconstructed image generated by decoding or a decoded image, and output the reconstructed image or the decoded image.

[00142] When the prediction mode used in decoding is intra mode, the switch may be switched to intra mode. Alternatively, when the prediction mode used in decoding is the inter mode, the switch may be switched to the inter mode.

[00143] The decoder 200 may obtain the recovered residual block by decoding the input bitstream and generate a prediction block. When the recovered residual block and the prediction block are obtained, the decoding apparatus 200 may generate a recovered block that becomes a decoding target by summing the recovered residual block with the prediction block. The decoding target block may be referred to as the current block.

[00144] The entropy decoding module 210 may generate symbols by entropy decoding the bitstream according to a probability distribution. The generated symbols may include a quantized level shape symbol. Here, the entropy decoding method may be a reverse process to the entropy encoding method described above.

[00145] In order to decode the transform coefficient level (quantized level), the entropy decoding module 210 may transform the coefficient in the form of a one-dimensional vector into the form of a two-dimensional block using a transform coefficient scan method.

[00146] The quantized level may be dequantized in dequantizing module 220 or inverted in inverse transform module 230 . The quantized level may be the result of dequantization and/or inverse transformation and may be generated as a reconstructed residual block. Here, dequantizer 220 may apply a quantization matrix to the quantized level.

[00147] When intra mode is used, intra prediction module 240 may generate a prediction block by performing, for the current block, a spatial prediction that uses a sample value of a block adjacent to a decoding target block and that has already been decoded.

[00148] When the inter mode is used, the motion compensation module 250 may generate a prediction block by performing, for the current block, motion compensation that uses a motion vector and a reference image stored in the reference picture buffer 270.

[00149] The adder 225 may generate a recovered block by adding the recovered residual block to the prediction block. The filter module 260 may apply at least one of a deblocking filter, an adaptive sample bias, and an adaptive loop filter to the reconstructed block or reconstructed image. The filter module 260 may output the reconstructed image. The reconstructed block or reconstructed image may be stored in the reference picture buffer 270 and used when performing inter-prediction. The reconstructed block processed by filter module 260 may be part of a reference image. That is, the reference image is a reconstructed image composed of the reconstructed blocks processed by the filter module 260 . The stored reference image can be used later for inter-prediction or motion compensation.

[00150] FIG. 3 is a view schematically showing an image partition structure in image encoding and decoding. Fig. 3 schematically shows an example of splitting one unit into many lower units.

[00151] In order to efficiently partition an image, a coding unit (CU) can be used in encoding and decoding. A coding unit may be used as a base unit for encoding/decoding an image. In addition, the coding unit may be used as a unit for distinguishing between the intra prediction mode and the inter prediction mode in image encoding/decoding. A coding unit may be a base unit used for prediction, transform, quantization, inverse transform, dequantization, or a transform coefficient encoding/decoding process.

[00152] With reference to FIG. 3, the picture 300 is sequentially partitioned into a largest coding unit (LCU), and the LCU is defined as a partition structure. Here, an LCU can be used in the same sense as a coding tree unit (CTU). Splitting a unit may mean splitting a block associated with a unit. Unit-depth information may be included in the block split information. The depth information may represent the number of times and/or the extent to which the unit is broken. One unit may be broken down into multiple lower level units associated hierarchically with depth information based on a tree structure. In other words, a certain unit and a lower-level unit generated by splitting a given unit can correspond to a node and a child node of this node, respectively. Each subdivided lower unit may have depth information. The depth information may be information representing the size of a CU and may be stored in each CU. The depth of the unit represents the number of times and/or degrees of partitioning of the unit. Therefore, the split information of the lower level unit may contain information about the size of the lower level unit.

[00153] A split structure may mean a distribution of a coding unit (CU) within an LCU 310. Such a distribution may be determined according to whether one CU should be split into a plurality (a positive integer equal to or greater than 2, including 2, 4, 8, 16, etc.) CU. The horizontal size and vertical size of the CU generated by splitting may respectively be half of the horizontal size and vertical size of the CU before splitting, or may respectively be smaller than the horizontal size and vertical size before splitting, according to the number of times of splitting. A CU can be recursively split into multiple CUs. By recursively splitting, at least one of the height and width of the CU after splitting may be reduced compared to at least one of the height and width of the CU before splitting. Splitting a CU may be recursively performed to a predetermined depth or a predetermined size. For example, the LCU depth may be 0 and the smallest coding unit (SCU) depth may be a predetermined maximum depth. Here, an LCU may be a coding unit having a maximum coding unit size, and an SCU may be a coding unit having a minimum coding unit size, as described above. The split starts from LCU 310, the depth of the CU increases by 1 as the horizontal size and/or vertical size of the CU is reduced by the split. For example, for each depth, a CU that is not divided may have a size of 2N×2N. Also, in the case of a CU that is partitioned, a CU with a size of 2N×2N may be split into four CUs with a size of N×N. The size of N can decrease by half when the depth increases by 1.

[00154] In addition, information about whether to split a CU can be represented using CU split information. The split information may be 1-bit information. All CUs except SCUs may include split information. For example, when the value of the split information is equal to the first value, the CU may not be split, when the value of the split information is equal to the second value, the CU may be split.

[00155] With reference to FIG. 3, an LCU having a depth of 0 may be a 64x64 block. 0 can be the minimum depth. An SCU having a depth of 3 may be an 8x8 block. 3 can be the maximum depth. CUs as 32x32 blocks and 16x16 blocks can be respectively represented as depth 1 and depth 2.

[00156] For example, when one coding unit is split into four coding units, the horizontal size and vertical size of the four split coding units may be equal to half the size of the horizontal and vertical size of the CU before splitting. In one embodiment, when a coding unit having a size of 32x32 is split into four coding units, each of the four divided coding units may have a size of 16x16. When one coding unit is split into four coding units, it can be said that the coding unit can be split into a quadtree shape.

[00157] For example, when one coding unit is split into two sub-coding units, the horizontal or vertical size (width or height) of each of the two sub-coding units may be half the horizontal or vertical size of the original coding unit. For example, when a coding unit having a size of 32×32 is vertically split into two sub-coding units, each of the two sub-coding units may have a size of 16×32. For example, when a coding unit having a size of 8×32 is horizontally split into two sub-coding units, each of the two sub-coding units may have a size of 8×16. When one coding unit is split into two sub-coding units, the coding unit can be said to be binary split or split by a binary tree split structure.

[00158] For example, when one coding unit is split into three coding sub-units, the horizontal or vertical dimension of the coding unit may be split in a ratio of 1:2:1, thereby forming three sub-coding units whose horizontal or vertical dimensions are in the ratio 1:2:1. For example, when a coding unit having a size of 16x32 is horizontally divided into three coding sub-units, the three coding sub-units may have sizes of 16x8, 16x16, and 16x8, respectively, in order from top to bottom. lower sub-unit of coding. For example, when a coding unit having a size of 32x32 is vertically divided into three coding sub-units, the three coding sub-units may have sizes of 8x32, 16x32, and 8x32, respectively, in order from left to right sub- coding units. When one coding unit is split into three sub-coding units, the coding unit can be said to be ternary split or split by a ternary tree splitting structure.

[00159] FIG. 3, a coding tree unit (CTU) 320 is an example of a CTU to which a quadtree split structure, a binary tree split structure, and a ternary tree split structure are applied.

[00160] As described above, in order to split the CTU, at least one of a quadtree split structure, a binary tree split structure, and a ternary tree split structure can be applied. Various tree partitioning structures may be sequentially applied to CTUs, according to a predetermined order of precedence. For example, the quadtree split structure may be advantageously applied to CTUs. A coding unit that can no longer be split using a split quadtree structure may correspond to a leaf node of the quadtree. The coding unit corresponding to a quadtree leaf node may serve as the root node of a binary and/or ternary tree partitioning structure. That is, a coding unit corresponding to a quadtree leaf node may be further split according to a binary tree splitting structure or a ternary tree splitting structure, or may no longer be split. Therefore, by preventing a coding block that is the result of splitting a binary tree or splitting a ternary tree of a coding unit corresponding to a leaf node of a quadtree from further splitting the quadtree, splitting the block and/or signaling the splitting information can be efficiently performed.

[00161] The fact that a coding unit corresponding to a quadtree node is split can be signaled using quad split information. The quad-split information having a first value (eg, “1”) may indicate that the current coding unit is split according to a quadtree split structure. The quad-split information having a second value (eg, “0”) may indicate that the current coding unit is not split according to a quadtree split structure. The squaring information may be a flag having a predetermined length (eg, one bit).

[00162] There may be no priority between splitting a binary tree and splitting a ternary tree. That is, a coding unit corresponding to a leaf node of the quadtree may further be subjected to an arbitrary split from a binary tree split and a ternary tree split. In addition, a coding unit generated by binary tree splitting or ternary tree splitting may be subject to further binary tree splitting or further ternary tree splitting, or may not be split further.

[00163] A tree structure in which there is no priority among binary tree splitting and ternary tree splitting is referred to as a multitype tree structure. A coding unit corresponding to a leaf node of a quadtree can serve as the root node of a tree of a set of types. Whether or not to split a coding unit that corresponds to a tree node of the plurality of types may be signaled using at least one of the multiple type tree split indication information, the split direction information, and the split tree information. To split a coding unit corresponding to a tree node of the set of types, the split type tree split indication information, split direction, and split tree information may be sequentially signaled.

[00164] The set type tree split indication information having a first value (eg, “1”) may indicate that the current coding unit is to be subjected to a set type tree split. The type set tree split indication information having a second value (eg, “0”) may indicate that the current coding unit should not be subject to type set tree split.

[00165] When a coding unit corresponding to a tree node of the set of types is further split according to a splitting structure of the set of type tree, the coding unit may include splitting direction information. The split direction information may indicate in which direction to split the current coding unit to split the tree of the plurality of types. The split direction information having a first value (eg, “1”) may indicate that the current coding unit is to be split vertically. Split direction information having a second value (eg, “0”) may indicate that the current coding unit should be split horizontally.

[00166] When a coding unit corresponding to a node of a tree of a set of types is further split according to a splitting structure of a tree of a set of types, the current coding unit may include splitting tree information. The split tree information may indicate a split tree structure to be used to split a tree node of the plurality of types. The split tree information having a first value (eg, “1”) may indicate that the current coding unit is to be split according to a binary tree split structure. The split tree information having a second value (eg, "0") may indicate that the current coding unit is to be split according to a ternary tree split structure.

[00167] The split indication information, the split tree information, and the split direction information may each be a flag having a predetermined length (eg, one bit).

[00168] At least any one of quadtree split indication information, multiple type tree split indication information, split direction information, and split tree information can be entropy encoded/decoded. For entropy encoding/decoding of these types of information, information about a neighboring coding unit adjacent to the current coding unit may be used. For example, there is a high probability that the split type (split or unsplit, split tree and/or split direction) of the left neighbor coding unit and/or top neighbor coding unit of the current coding unit is similar to that of the current coding unit. Therefore, context information for entropy encoding/decoding information about the current coding unit can be derived from information about neighboring coding units. The neighbor coding unit information may include at least any one of quad split information, multiple type tree split indication information, split direction information, and split tree information.

[00169] As another example, from binary tree splitting and ternary tree splitting, binary tree splitting can preferably be performed. That is, the current coding unit may be mainly subjected to splitting the binary tree, and then the coding unit corresponding to the leaf node of the binary tree may be set as the root node for splitting the ternary tree. In this case, neither quadtree splitting nor binary tree splitting may be performed on the coding unit corresponding to the ternary tree node.

[00170] A coding unit that cannot be split according to a quadtree split structure, a binary tree split structure, and/or a ternary tree split structure becomes a base unit for encoding, prediction, and/or transformation. That is, the coding unit cannot be further split for prediction and/or transformation. Therefore, split structure information and split information used to split a coding unit into prediction units and/or transform units may not be represented in the bitstream.

[00171] However, when the size of a coding unit (i.e., the base unit to split) is larger than the size of the maximum transform unit, the coding unit may be recursively split until the size of the coding unit decreases to be equal to or smaller than than the maximum transform block size. For example, when the size of a coding unit is 64x64 and when the size of the maximum transformation block is 32x32, the coding unit may be divided into four 32x32 blocks for transformation. For example, when the size of a coding unit is 32x64 and the size of the maximum transformation block is 32x32, the coding unit may be split into two 32x32 blocks for transformation. In this case, the split of a coding unit for a transform is not separately signaled and may be determined by comparing between the horizontal or vertical size of the coding unit and the horizontal or vertical size of the maximum transform block. For example, when the horizontal dimension (width) of the coding unit is larger than the horizontal dimension (width) of the maximum transform block, the coding unit may be vertically divided in half. For example, when the vertical dimension (length) of the coding unit is larger than the vertical dimension (length) of the maximum transform block, the coding unit may be horizontally divided in half.

[00172] Maximum and/or minimum coding unit size information and maximum and/or minimum transform block size information may be signaled or determined at a higher coding unit level. The higher level may be, for example, a sequence level, a picture level, a slice level, a tile group level, a tile level, or the like. For example, the minimum size of a coding unit may be defined as 4×4. For example, the maximum transform block size may be defined as 64x64. For example, the minimum transform block size may be defined as 4×4.

[00173] Minimum size information (minimum quadtree size) of a coding unit corresponding to a quadtree leaf node and/or maximum depth information (maximum tree depth for a set type tree) from the root node to the leaf node of the set type tree may be signaled or determined at higher level of coding unit. For example, the higher level may be a sequence level, a picture level, a slice level, a tile group level, a tile level, or the like. The minimum quadtree size information and/or the maximum tree depth information of the plurality of types may be signaled or determined for each of the intra-picture slice and the inter-picture slice.

[00174] The difference information between the CTU size and the maximum transform unit size may be signaled or determined at a higher coding unit level. For example, the higher level may be a sequence level, a picture level, a slice level, a tile group level, a tile level, or the like. Information about the maximum size of coding units corresponding to the respective nodes of the binary tree (hereinafter referred to as the maximum size of the binary tree) may be determined based on the unit size of the coding tree and the difference information. The maximum size of coding units corresponding to the respective nodes of the ternary tree (hereinafter referred to as the maximum size of the ternary tree) may vary depending on the slice type. For example, for an intra-picture slice, the maximum size of a ternary tree could be 32x32. For example, for an inter-picture slice, the maximum ternary tree size could be 128x128. For example, the minimum size of coding units corresponding to the respective nodes of the binary tree (hereinafter referred to as the minimum size of the binary tree) and/or the minimum size of the coding units corresponding to the respective nodes of the ternary tree (hereinafter referred to as the minimum size of the ternary tree) may be set as minimum coding block size.

[00175] As another example, the maximum binary tree size and/or the maximum ternary tree size may be signaled or determined at the slice level. Alternatively, the minimum binary tree size and/or the minimum ternary tree size may be signaled or determined at the slice level.

[00176] Depending on the size and depth information of the various blocks described above, quad split information, multiple type tree split indication information, split tree information, and/or split direction information may or may not be included in the bitstream.

[00177] For example, when the coding unit size is not larger than the minimum quadtree size, the coding unit does not contain quad-partition information. Thus, squaring information can be derived from the second value.

[00178] For example, when the dimensions (horizontal and vertical dimensions) of an encoding unit corresponding to a tree node of the set of types are larger than the maximum dimensions (horizontal and vertical dimensions) of a binary tree and/or the maximum dimensions (horizontal and vertical dimensions) of a ternary tree, the unit encoding may not be binary separated or ternary divided. Accordingly, the split type tree split indication information may not be signaled, but may be derived from the second value.

[00179] Alternatively, when the dimensions (horizontal and vertical dimensions) of the coding unit corresponding to a tree node of the set of types are the same as the maximum dimensions (horizontal and vertical dimensions) of the binary tree and/or twice as large as the maximum dimensions (horizontal and vertical dimensions) of a ternary tree, the coding unit cannot be further binary-separable or ternary-separable. Accordingly, the split type tree split indication information may not be signaled, but may be derived from the second value. This is because when a coding unit is split according to a binary tree split structure and/or a ternary tree split structure, a coding unit smaller than the minimum binary tree size and/or the minimum ternary tree size is generated.

[00180] Alternatively, splitting a binary tree or splitting a ternary tree may be limited based on the size of the virtual pipeline data unit (hereinafter, pipeline buffer size). For example, when a coding unit is divided into sub-coding units that do not fit the pipeline buffer size by binary tree splitting or ternary tree splitting, the corresponding binary tree splitting or ternary tree splitting may be limited. The size of the pipeline buffer may be the size of the maximum transform block (eg, 64×64). For example, when the pipeline buffer size is 64x64, the division below may be limited.

[00181] - N×M (N and/or M is 128) Ternary tree split for coding units

[00182] - 128×N (N<=64) Binary tree split in horizontal direction for coding units

[00183] - N×128 (N<=64) Splitting the binary tree in the vertical direction for coding units

[00184] Alternatively, when the depth of a coding unit corresponding to a tree node of the type set is equal to the maximum depth of the type set tree, the coding unit cannot be further binarized and/or ternary tiled. Accordingly, the split type tree split indication information may not be signaled, but may be derived from the second value.

[00185] Alternatively, only when at least one of binary tree splitting in the vertical direction, binary tree splitting in the horizontal direction, ternary tree splitting in the vertical direction, and ternary tree splitting in the horizontal direction is possible for the coding unit corresponding to the tree node of the set of types, the multitype tree split indication information may be signalled. Otherwise, the coding unit cannot be binarized and/or ternary binarized. Accordingly, the split type tree split indication information may not be signaled, but may be derived from the second value.

[00186] Alternatively, only when, for the coding unit corresponding to a tree node of the set of types, both a binary tree split in the vertical direction and a binary tree split in the horizontal direction, or both a ternary tree split in the vertical direction and a ternary tree split in the horizontal direction, split direction information can be signaled. Otherwise, split direction information may not be signaled, but may be derived from a value indicating possible split directions.

[00187] Alternatively, only when, for the coding tree corresponding to the tree node of the set of types, both a binary tree split in the vertical direction and a ternary tree split in the vertical direction, or both a binary tree split in the horizontal direction and a ternary tree split in the horizontal direction, split tree information can be signaled. Otherwise, the split tree information may not be signaled, but may be derived from a value indicating a possible split of the tree structure.

[00188] FIG. 4 is a view showing an intra prediction process.

[00189] Arrows from the center outward in FIG. 4 may represent prediction directions of intra-prediction modes.

[00190] Intra-coding and/or decoding may be performed using a neighbor block reference sample of the current block. The neighbor block may be a reconstructed neighbor block. For example, intra-coding and/or decoding may be performed using an encoding parameter or a reference sample value included in the reconstructed adjacent block.

[00191] A prediction block may mean a block generated by performing intra-prediction. The prediction block may correspond to at least one of the CU, PU, and TU. A prediction block unit may have a size of one of CU, PU, and TU. The prediction block may be a square block having a size of 2x2, 4x4, 16x16, 32x32, or 64x64, etc., or may be a rectangular block having a size of 2x8, 4x8, 2x16, 4x16 and 8x16 etc.

[00192] Intra prediction may be performed according to the intra prediction mode for the current block. The number of intra prediction modes that the current block may have may be a fixed value, and may be a value defined differently according to an attribute of the prediction block. For example, a prediction block attribute may contain the size of the prediction block and the shape of the prediction block, etc.

[00193] The number of intra prediction modes can be fixed to N regardless of the block size. Or the number of intra-prediction modes can be 3, 5, 9, 17, 34, 35, 36, 65 or 67, etc. Alternatively, the number of intra prediction modes may vary according to block size or color component type, or both. For example, the number of intra prediction modes may vary according to whether the color component is a luminance signal or a chrominance signal. For example, as the block size becomes large, the number of intra prediction modes may increase. Alternatively, the number of intra-prediction modes of the luma component block may be greater than the number of intra-prediction modes of the chrominance component block.

[00194] The intra-prediction mode may be a non-angle mode or an angle mode. The non-angular mode may be a DC mode or a planar mode, and the angular mode may be a prediction mode having a specific direction or angle. The intra prediction mode may be expressed by at least one of a mode number, a mode value, a mode number symbol, a mode angle, and a mode direction. The number of intra prediction modes may be M, which is greater than 1, including non-angular and angular modes. For intra-prediction of the current block, the step of determining whether the samples included in the reconstructed neighboring block can be used as reference samples of the current block can be performed. When there is a sample that cannot be used as a reference sample of the current block, a value obtained by duplicating or interpolating at least one sample value among the samples included in the reconstructed adjacent block, or both, can be used to replace an unused sample value for the sample, thus, the replaced sample value is used as the reference sample of the current block.

[00195] FIG. 7 is a diagram illustrating reference samples that may be used for intra prediction.

[00196] As shown in FIG. 7, at least one of reference sample line 0 and reference sample line 3 may be used for intra-prediction of the current block. In FIG. 7, segment A and segment F samples may be padded with samples closest to segment B and segment E, respectively, instead of being extracted from the reconstructed neighboring block. Index information indicating a reference sample line to be used for intra-prediction of the current block may be signaled. When the upper boundary of the current block is the CTU boundary, only reference sample line 0 may be available. Therefore, in this case, the index information may not be signaled. When a reference sample line other than reference sample line 0 is used, filtering for a prediction block to be described later may not be performed.

[00197] In intra-prediction, a filter may be applied to at least one of a reference sample and a prediction sample based on the intra-prediction mode and the current block size.

[00198] In the case of the planar mode, when generating the prediction block of the current block, in accordance with the position of the prediction target sample in the prediction block, the sample value of the prediction target sample can be generated using the weighted sum of the top and left side reference samples for the current sample, and the reference selections of the upper right side and lower left side of the current block. In addition, in the case of the DC mode, when generating the prediction block of the current block, the average value of the reference samples of the top and left sides of the current block can be used. Further, in the case of the angular mode, a prediction block may be generated using a reference sample of the top side, left side, top right side, and/or bottom left side of the current block. In order to generate a prediction sample value, a real number unit interpolation may be performed.

[00199] In the case of intra-prediction between color components, a prediction block for the current block of the second color component may be generated based on the corresponding reconstructed block of the first color component. For example, the first color component may be a luminance component and the second color component may be a chrominance component. For intra-prediction between color components, linear model parameters between the first color component and the second color component may be obtained based on the template. The pattern may include the top and/or left adjacent samples of the current block and the top and/or left adjacent samples of the reconstructed block of the first color component corresponding to it. For example, the parameters of the linear model may be derived using the sample value of the first color component having the maximum value among the samples in the template and the sample value of the second color component corresponding thereto and the sample value of the first color component having the minimum value among the samples in the template, and sample values of the second color component corresponding to it. When the linear model parameters are inferred, the corresponding reconstructed block can be applied to the linear model to generate a prediction block for the current block. According to the video format, downsampling may be performed on adjacent samples of the reconstructed block of the first color component and the corresponding reconstructed block. For example, when one sample of the second color component corresponds to four samples of the first color component, the four samples of the first color component may be downsampled to compute one corresponding sample. In this case, linear model derivation and intra-prediction between color components can be performed based on the respective downsampled samples. Whether or not to perform intra-prediction between color components and/or pattern range may be signaled as an intra-prediction mode.

[00200] The current block may be split into two or four sub-blocks in the horizontal or vertical direction. Broken sub-blocks can be sequentially restored. That is, intra-prediction may be performed on a sub-block to generate a prediction sub-block. In addition, dequantization and/or inverse transformation may be performed on the sub-blocks to generate residual sub-blocks. The recovered subblock may be generated by adding the prediction subblock to the residual subblock. The reconstructed sub-block can be used as a reference sample for sub-sub-block intra-prediction. A sub-block may be a block containing a predetermined number (eg, 16) or more samples. Accordingly, for example, when the current block is an 8×4 or 4×8 block, the current block may be divided into two sub-blocks. In addition, when the current block is a 4x4 block, the current block cannot be subblocked. When the current block has other dimensions, the current block may be split into four sub-blocks. Information about whether to perform intra-prediction based on sub-blocks and/or the splitting direction (horizontal or vertical) may be signaled. Sub-block based intra-prediction can only be limited to execution when reference sample line 0 is used. When sub-block-based intra-prediction is performed, filtering for a prediction block to be described later may not be performed.

[00201] The final prediction block may be generated by performing filtering on a prediction block that is intra-predicted. Filtering may be performed by applying predefined weights to the filter target, left pivot, top pivot, and/or top left pivot. The weight and/or reference sample (range, position, etc.) used for filtering may be determined based on at least one of the block size, the intra-prediction mode, and the position of the filter target sample in the prediction block. Filtering can only be performed in the case of a predefined intra-prediction mode (eg, DC, planar, vertical, horizontal, diagonal, and/or adjacent diagonal modes). The adjacent diagonal mode may be a mode in which k is added to or subtracted from the diagonal mode. For example, k may be a positive integer 8 or less.

[00202] The intra-prediction mode of the current block may be entropy encoded/decoded by predicting the intra-prediction mode of a block adjacent to the current block. When the intra prediction modes of the current block and the neighboring block are identical, information that the intra prediction modes of the current block and the neighboring block are identical can be signaled using predetermined flag information. In addition, information of an intra prediction mode indicator that is identical to the intra prediction mode of the current block among the intra prediction modes of a plurality of neighboring blocks can be signaled. When the intra prediction modes of the current block and the neighboring block are different, the intra prediction mode information of the current block can be entropy encoded/decoded by performing entropy encoding/decoding based on the intra prediction mode of the neighboring block.

[00203] FIG. 5 is a diagram illustrating an embodiment of an inter-prediction process.

[00204] FIG. 5, a rectangle can represent a picture. In FIG. 5, an arrow represents the prediction direction. Pictures can be classified into intra pictures (I-pictures), predictive pictures (P-pictures), and bidirectional prediction pictures (bi-predictive) (B-pictures) according to their coding type.

[00205] An I-picture can be encoded by intra-prediction without the need for inter-picture (inter-picture) prediction. A P-picture may be encoded by inter-picture prediction using a reference picture that is present in one direction (ie, forward or backward) relative to the current block. The B-picture may be encoded by inter-picture prediction using reference pictures that are preset in two directions (ie, forward and backward) relative to the current block. When inter-picture prediction is used, the encoder may perform inter-prediction or motion compensation, and the decoder may perform the corresponding motion compensation.

[00206] An embodiment of inter-picture (inter-) prediction will be described in detail below.

[00207] Inter-prediction or motion compensation may be performed using the reference picture and motion information.

[00208] Motion information of the current block may be output during inter-prediction by each of the encoder 100 and the decoder 200. The motion information of the current block may be inferred using the motion information of the reconstructed adjacent block, the motion information of the aligned block (also referred to as a col block or aligned block), and/or the block adjacent to the aligned block. A merged block may mean a block that is spatially located at the same position as the current block in a previously restored merged picture (also referred to as a col picture or merged picture). The merged picture may be one picture from one or more reference pictures included in the reference picture list.

[00209] The motion information output method may differ depending on the prediction mode of the current block. For example, the prediction mode applied for inter-prediction includes AMVP mode, merge mode, skip mode, motion vector difference merge mode, sub-block merge mode, triangular split mode, inter-intra combined prediction mode, affine mode, etc. P. Here, the fusion mode may be referred to as the motion fusion mode.

[00210] For example, when AMVP is used as the prediction mode, at least one of the motion vectors of the reconstructed adjacent blocks, the motion vectors of the aligned blocks, the motion vectors of blocks adjacent to the aligned blocks, and the (0, 0) motion vector may be defined in as motion vector candidates for the current block, and a list of motion vector candidates is generated using the motion vector candidates. The motion vector candidate of the current block may be inferred using the generated list of motion vector candidates. The motion information of the current block may be determined based on the derived motion vector candidate. Motion vectors of aligned blocks or motion vectors of blocks adjacent to aligned blocks may be referred to as temporal motion vector candidates, and motion vectors of reconstructed adjacent blocks may be referred to as spatial motion vector candidates.

[00211] Encoding apparatus 100 may calculate a motion vector difference (MVD) between a motion vector of the current block and a motion vector candidate, and may perform motion vector difference (MVD) entropy coding. In addition, the encoder 100 can perform entropy encoding of a motion vector candidate index and generate a bitstream. The motion vector candidate index may indicate the optimal motion vector candidate among the motion vector candidates included in the motion vector candidate list. The decoding apparatus may perform entropy decoding on a motion vector candidate index included in the bitstream, and may select a motion vector candidate of the decoding target block from among the motion vector candidates included in the motion vector candidate list using the entropy decoded motion vector candidate index. In addition, the decoding apparatus 200 can sum the entropy decoded MVD and the motion vector candidate extracted by the entropy decoding, thereby outputting the motion vector of the decoding target block.

[00212] Meanwhile, the encoder 100 can perform entropy encoding on the resolution information of the computed MVD. The decoder 200 may adjust the resolution of the entropy decoded MVD using the resolution information of the MVD.

[00213] Meanwhile, the encoding apparatus 100 calculates a motion vector difference (MVD) between a motion vector and a motion vector candidate in the current block based on the affine model, and performs entropy encoding on the MVD. The decoder 200 derives a motion vector for each subblock by deriving the affine control motion vector of the decoding target block through the sum of the entropy decoded MVD and the affine control motion vector candidate.

[00214] The bitstream may include a reference picture index indicating the reference picture. The reference picture index may be entropy encoded by the encoder 100 and then signaled as a bit stream to the decoder 200 . The decoding apparatus 200 may generate a prediction block from a decoding target block based on the derived motion vector and the reference picture index information.

[00215] Another example of a method for deriving current motion information may be a merge mode. Merging mode may mean a way to merge the movement of a plurality of blocks. The merge mode may mean a mode of deriving the motion information of the current block from the motion information of neighboring blocks. When the merge mode is applied, the merge candidate list may be generated using motion information of reconstructed neighboring blocks and/or motion information of aligned blocks. The motion information may include at least one of a motion vector, a reference picture index, and an inter prediction indicator. The prediction indicator may indicate unidirectional prediction (L0 prediction or L1 prediction) or bidirectional prediction (L0 prediction and L1 prediction).

[00216] The merge candidate list may be a list of stored motion information. The motion information included in the merge candidate list may be at least one of motion information (spatial merge candidate) of an adjacent block adjacent to the current block, motion information (temporal merge candidate) of a merged block of the current block in the reference picture, new motion information, generated by a combination of the motion information coming out of the merge candidate list, the motion information (history-based merge candidate) of the block that is coded/decoded before the current block, and the null merge candidate.

[00217] Encoder 100 may generate a bitstream by performing entropy encoding on at least one of the merge flag and merge index, and may signal the bitstream to decoder 200. The merge flag may be information indicating whether the merge mode should be performed for each block, and the merge index may be information indicating which neighboring block among the neighboring blocks of the current block is the target block of the merge. For example, the adjacent blocks of the current block may include a left adjacent block on the left side of the current block, an upper adjacent block located above the current block, and a temporal adjacent block temporally adjacent to the current block.

[00218] Meanwhile, the encoder 100 performs entropy encoding on the correction information to correct the motion vector among the motion information of the merge candidate, and signals this to the decoder 200. The decoder 200 may correct the merge candidate motion vector selected by the merge index based on the correction information. Here, the correction information may include at least one of whether or not to perform correction, correction direction information, and correction size information. As described above, a prediction mode that corrects a motion vector of a merge candidate based on signaled correction information may be referred to as a merge mode having a motion vector difference.

[00219] The skip mode may be a mode in which motion information of a neighboring block is applied to the current block as is. When the skip mode is applied, the encoder 100 may entropy encode information that the motion information of a particular block is to be used as the current block's motion information to generate a bitstream, and may signal the bitstream to the decoder 200. Encoder 100 may not signal a syntax element regarding at least any one of motion vector difference information, encoder block flag, and transform coefficient level to decoder 200.

[00220] The sub-block merge mode may mean a mode that outputs motion information in units of coding unit (CU) sub-blocks. When the sub-block merge mode is applied, the sub-block merge candidate list may be generated using the motion information (sub-block-based temporal merge candidate) of the sub-block aligned with the current sub-block in the reference picture and/or the affine control point motion vector merge candidate.

[00221] The triangular split mode may mean a mode that outputs motion information by splitting the current block into diagonal directions, outputs each prediction sample using each derived motion information, and extracts a prediction sample of the current block by weighting each of the output prediction samples.

[00222] The combined inter-intra prediction mode may mean a mode that outputs a prediction sample of the current block by weighting the prediction sample generated by inter-prediction and the prediction sample generated by intra-prediction.

[00223] The decoding device 200 can independently correct the output motion information. The decoding apparatus 200 may search in a predetermined area based on a reference block indicated by the outputted motion information, and output motion information having a minimum SAD as corrected motion information.

[00224] The decoding apparatus 200 may compensate for the prediction sample output by inter-prediction using the optical stream.

[00225] FIG. 6 is a diagram illustrating the conversion and quantization process.

[00226] As shown in FIG. 6, a transformation and/or quantization process is performed on the residual signal to generate a quantized level signal. The residual signal is the difference between the original block and the prediction block (ie, intra-prediction block or inter-prediction block). A prediction block is a block generated by intra-prediction or inter-prediction. The transformation can be a primary transformation, a secondary transformation, or both. Primary transform of the residual signal results in transform coefficients, and secondary transform of the transform coefficients results in secondary transform coefficients.

[00227] At least one scheme selected from various conversion schemes that are predefined is used to perform the primary conversion. For example, examples of predefined transform schemes include discrete cosine transform (DCT), discrete sine transform (DST), and Karhunen-Loeve transform (KLT). The transform coefficients generated by the primary transform may be subjected to a secondary transform. The transform schemes used for the primary transform and/or the secondary transform may be determined according to the coding parameters of the current block and/or neighboring blocks of the current block. Alternatively, conversion information indicating a conversion scheme may be signaled. The DCT-based transform may include, for example, DCT-2, DCT-8, and the like. The DST-based transform may include, for example, DST-7.

[00228]

[00229] A quantized level signal (quantization coefficients) may be generated by performing quantization of a residual signal or the result of performing a primary transform and/or a secondary transform. The quantized level signal may be scanned according to at least one of up-right diagonal scan, vertical scan, and horizontal scan, depending on the block intra-prediction mode or block size/shape. For example, when the coefficients are scanned in an up-right diagonal scan, the block-form coefficients are converted to a one-dimensional vector form. In addition to the up-right diagonal scan, a horizontal scan of a horizontal scan of a 2D coefficient block shape or a vertical scan of a vertical scan of a 2D coefficient block shape may be used depending on the intra-prediction mode and/or transform block size. The scanned quantized-level coefficients may be entropy encoded for insertion into a bitstream.

[00230] The decoder performs entropy decoding of the bitstream to obtain quantized-level coefficients. The quantized level coefficients can be arranged in a two-dimensional block form by inverse scanning. For reverse scanning, at least one of upward-right diagonal scanning, vertical scanning, and horizontal scanning may be used.

[00231] The quantized level coefficients may then be dequantized, then subjected to a second inverse transform if necessary, and finally a primary inverse transform if necessary to generate a reconstructed residual signal.

[00232] Dynamic range demapping may be performed on the luma component recovered by intra-prediction or inter-prediction before in-loop filtering. The dynamic range can be divided into 16 equal parts, and the display function for each part can be signaled. The display function can be signaled at the slice level or the tile group level. A reverse mapping function for performing reverse mapping may be derived based on the mapping function. Peak filtering, reference picture storage, and motion compensation are performed on the inverse mapping area, and the prediction block generated by inter-prediction is converted to a displayable area by mapping using a mapping function, and then used to generate a reconstructed block. However, since intra-prediction is performed in the mapped area, a prediction block generated by intra-prediction can be used to generate a reconstructed block without mapping/demapping.

[00233] When the current block is a residual block of a color component, the residual block can be converted to an inverse display area by performing scaling of the chrominance component of the displayed area. Zoom availability can be signaled at the slice level or the tile group level. Scaling can only be applied when mapping is available for the luminance component and both the luma component split and the chroma component split follow the same tree structure. The scaling may be performed based on the average value of the samples of the luminance prediction block corresponding to the color difference block. In this case, when the current block uses inter-prediction, the luminance prediction block may mean a mapped luminance prediction block. The value needed for scaling can be obtained by referring to a lookup table using the index of the chunk to which the mean value of the samples of the luminance predictor belongs. Finally, by scaling the residual block using the inferred value, the residual block can be switched to the inverse display area. Then, chrominance component block reconstruction, intra-prediction, inter-prediction, contour filtering, and reference picture storage may be performed in the inverse mapping area.

[00234] Information indicating whether display/inverse display of the luminance component and the chrominance component is available may be signaled via a set of sequence parameters.

[00235] A prediction block of the current block may be generated based on a block vector indicating an offset between the current block and a reference block in the current picture. Thus, the prediction mode for generating a prediction block with reference to the current picture is called an intra-block copy (IBC) mode. The IBC mode may be applied to MxN (M<=64, N<=64) coding units. The IBC mode may include a skip mode, a merge mode, an AMVP mode, and the like. In the case of a skip mode or a merge mode, a list of merge candidates is generated and the merge index is signaled so that one merge candidate can be specified. The block vector of the specified merge candidate may be used as the block vector of the current block. The merge candidate list may include at least one of a spatial candidate, a history based candidate, a candidate based on an average of two candidates, and a null merge candidate. In the case of the AMVP mode, the delta block vector may be signaled. In addition, the prediction block vector can be derived from the left neighbor block and the top neighbor block of the current block. The index for the adjacent block to be used can be signaled. The IBC mode prediction block is included in the current CTU or left CTU and limited to a block in the already recovered area. For example, the value of the block vector may be constrained such that the prediction block of the current block is located in a region of three 64x64 blocks preceding the 64x64 block to which the current block belongs, in coding/decoding order. By limiting the value of the block vector in this way, memory consumption and device complexity according to the implementation of the IBC mode can be reduced.

[00236]

[00237] Next, a method for generating a motion information list according to an embodiment of the present invention will be described.

[00238] Further, the motion information list may refer to a list that stores motion information generated when encoding or decoding an image.

[00239] According to an embodiment of the present invention, motion information generated in inter prediction may be stored in a motion information list, and motion information may be generated using the motion information list in inter prediction of the next encoding/decoding target block.

[00240] Here, the motion information may mean at least one of a motion vector, a reference picture index, an inter prediction indicator as described above, and a prediction list use flag, reference picture list information, a reference picture, a motion vector candidate, an index a motion vector candidate, a merge candidate, a merge index, and the like.

[00241] The motion information list may store motion information generated in a predetermined area.

[00242] As an example, the motion information list may be initialized by deleting the motion information from the motion information list or generating a new motion information list when encoding/decoding is completed in a predetermined area so that the area changes.

[00243] That is, the motion information list may be generated based on a predefined area (or a predefined section, a predefined unit). Here, the predetermined area related to the motion information list may be a unit larger than the unit in which inter prediction is performed.

[00244] As an example, the predefined area related to the motion information list may be any one of a block consisting of one or more CUs, a CTU, a block consisting of one or more CTUs (e.g., a CTU string), a bar ( brick), tile, slice, picture, frame, and group of pictures (GOP).

[00245] A predefined area associated with the motion information list may be called an upper prediction unit (UPU) or an initialization area.

[00246] Meanwhile, the motion information list may be called an adaptive motion vector occurrence list (AMVOL) or a history-based motion vector predictor list (HMVP list) according to an embodiment.

[00247] Meanwhile, the motion information list can only be used when the encoder/decoder operates in the inter prediction mode or the IBC mode.

[00248] FIG. 8 and 9 are diagrams illustrating an encoder and a decoder using a motion information list.

[00249] With reference to FIG. 8 and 9, the encoder and the decoder can improve the prediction performance using the motion information stored in the motion information list in the inter-prediction process or the IBC prediction process.

[00250]

[00251] Meanwhile, the motion information list may be initialized or generated when encoding/decoding of a new UPU starts. Therefore, when encoding/decoding of a new UPU starts, the motion information list may not have motion information because inter-prediction is not performed in the new UPU. Since the motion information list has no motion information, the motion information list may not be used in inter prediction. In addition, when the amount of motion information stored in the motion information list is small, it is difficult to expect efficient coding because there is little information used for inter prediction.

[00252] In the present invention, when performing inter-prediction (or IBC prediction) when there is little or no motion information stored in the motion information list, a method is provided for further storing the predicted motion information in the motion information list to generate a motion information list .

[00253] Through the above method, it is possible to improve coding efficiency by more accurately performing inter prediction using a motion information list.

[00254]

[00255] The motion information list according to the present invention may store motion information generated in the current UPU.

[00256] FIG. 10 is a flowchart illustrating an inter prediction method using a motion information list according to the present invention.

[00257] With reference to FIG. 10, when the encoding/decoding of the new UPU starts, the step of initializing the motion information list is the step of deleting all information in the motion information list or returning it to a default value.

[00258] The motion information list prediction step is a step of predicting the motion information to be entered into the motion information list and adding it to the motion information list.

[00259] Here, the motion information list prediction step may add a plurality of predicted motion information to the motion information list.

[00260] The inter-prediction step includes a motion information prediction step, and is a step of predicting the current block via the reference picture.

[00261] The step of adding motion information is the step of adding motion information obtained as a result of inter prediction to the motion information list. According to an embodiment, the step of adding motion information may be omitted or changed. For example, when the ternary split mode is executed, the step of adding motion information may be omitted. That is, when the blocks resulting from splitting in the diagonal direction share the same list of motion information in the ternary split mode, the step of adding motion information may be omitted.

[00262] The inter prediction step and the motion information adding step may be performed in units of blocks, and may be performed for all blocks in the corresponding UPU.

[00263] After checking whether execution is completed for all blocks in the UPU, when execution is not completed, the process proceeds to the next block so that inter-prediction can be performed.

[00264] When inter-prediction is performed on all blocks in the UPU and the UPU motion information list is no longer used, the motion information list may be initialized.

[00265] FIG. 11 is a flowchart illustrating an inter prediction method using a motion information list. Description of each step illustrated in the flowchart of FIG. 11 may be the same as the description of FIG. ten.

[00266] However, the point in time at which the motion information list prediction step of FIG. 11 may be different from the time of FIG. ten.

[00267] FIG. 10, the motion information list prediction step may be performed after the motion information list initialization step is performed. That is, the motion information list prediction step may be performed together with the motion information list initialization step, and thus the motion information list prediction step may be performed when the UPU changes.

[00268] FIG. 11, the motion information list prediction step may be performed after the motion information adding step is performed. That is, motion information list prediction may be performed whenever motion information is added to the motion information list.

[00269] FIG. 11 is different from FIG. 10 in that the additional motion information can be predicted using the motion information stored in the current motion information list.

[00270] In addition, in the case of FIG. 11, the predicted motion information may also be continuously updated or added to the motion information list by predicting more efficient candidates, but motion information list prediction is performed on each block, so that the amount of system computation may increase.

[00271] In the flowcharts of the examples of FIG. 10 and 11, the order of each step may vary. When encoding/decoding a block of another UPU in a situation where encoding/decoding of the current UPU is not completed, each step in FIG. 10 and 11 may be applied or omitted in a different order.

[00272] When there is no spatial reference relationship between blocks on a UPU boundary, as in the case where the UPU is a picture unit, a slice unit, or a tile unit, the encoding/decoding order cannot pass between UPUs different from each other. In this case, when encoding/decoding of the current UPU is not completed, encoding can be performed in the same UPU even after moving to the next block.

[00273] However, when a UPU is divided into multiple units within the same picture, slice, or tile, a case in which the next encoding/decoding unit belongs to another UPU may occur even when encoding/decoding is not completed in the current UPU according to the encoding/decoding sequence. In this case, different UPUs may have different motion information lists, and the coding information of the current block may be stored in the motion information list of the UPU to which the current block belongs. In this case, the motion information list may also be predicted from the motion information list stored in the other UPU up to now.

[00274] Meanwhile, the motion information list prediction step may be performed at both the motion information list initialization time and the motion information addition time.

[00275] FIG. 12 is a flowchart illustrating an inter-prediction method in which motion information list prediction is performed at a motion information list initialization time and a motion information addition time. Description of each step illustrated in the flowchart of FIG. 12 may be the same as in FIG. ten.

[00276] An inter prediction method using a motion information list has been described in FIG. 10-12. The inter-prediction step in FIG. 10-12 may be replaced with the IBC prediction step, and the block vector generated by the IBC prediction step may be included in the motion information list. In the following description, it is meant that inter-prediction includes IBC prediction.

[00277] Meanwhile, when using the shared merge list in IBC prediction, the step of adding motion information may be omitted.

[00278]

[00279] FIG. 13 and 14 illustrate an encoder and a decoder including a motion information list predictor.

[00280] With reference to FIG. 13 and 14, the inter-prediction module performs inter-prediction on the current block by means of the reference picture. Here, the inter prediction module may perform inter prediction by referring to the motion information list.

[00281] The motion information list adding unit may add motion information generated as a result of inter prediction to the motion information list.

[00282] The motion information list initialization module may initialize the information stored in the motion information list according to the change of the UPU or the creation of a new motion information list.

[00283] The motion information list prediction module can predict the motion information and store the motion information in the motion information list. Here, it is possible to refer to various types of information according to the motion information list prediction method performed by the motion information list prediction unit.

[00284] Connection (A) shows a connection between modules in case the motion information list prediction module uses information of the current block, such as the spatial and temporal position of the current block; connection (B) shows a connection between modules in case that the motion information list prediction module uses information of blocks spatially and temporally adjacent to the current block, or reference picture information with different types of information that the current block can access; and the connection (C) shows the connection between the modules in case the motion information list prediction module uses the information stored in the current motion information list. Therefore, at least one of the connections (A), (B) and (C) can be omitted according to the prediction method performed by the motion information list prediction unit.

[00285] Also, as shown in FIG. 10, the motion information list prediction unit may be executed when the motion information list is initialized. In this case, the motion information list prediction unit may operate by receiving a signal from the motion information list initialization unit via a connection (D). As shown in FIG. 11, when the motion information list prediction unit is operated, regardless of the initialization of the motion information list, the connection (D) may be omitted.

[00286] Meanwhile, the motion information encoding unit in FIG. 13 may encode motion information generated as a result of inter prediction. The motion information decoding unit shown in FIG. 14 decodes the signal encoded by the motion information encoding unit of FIG. 13 and allows inter-prediction to be performed in the same way as the encoder on the decoded signal.

[00287]

[00288] A pointer indicating whether to apply the motion information list during inter prediction may be transmitted in a parameter set such as a sequence parameter set or a picture parameter set, a tile header, a slice header, and the like.

[00289] FIG. 15 is a diagram illustrating an embodiment that performs signaling including a pointer indicating whether to apply a motion information list to sequence parameter set (SPS) syntax.

[00290] FIG. 16 is a diagram illustrating an embodiment that performs signaling including a pointer indicating whether to apply a motion information list to a picture parameter set (PPS) syntax.

[00291] FIG. 17 is a diagram illustrating an embodiment that performs signaling including a pointer indicating whether to apply the motion information list to the slice header syntax.

[00292] FIG. 15-17, amvol_enable_flag is information indicating whether inter prediction is enabled using the motion information list. When amvol_enable_flag is true, it indicates that inter-prediction using the motion information list is enabled, and when it is false, it indicates that inter-prediction using the motion information list is not enabled.

[00293] In addition, amvol_prediction_flag is information indicating whether motion information list prediction is performed. That is, the amvol_prediction_flag may indicate whether the motion information list prediction step of FIG. 10-12. amvol_prediction_flag can only be signaled when amvol_enable_flag is true.

[00294] Meanwhile, when amvol_enable_flag and amvol_prediction_flag are signaled in the slice header, as in the example of FIG. 17, signaling is performed when the slice type is not an I-slice. This is because the I-slice type slice does not perform inter prediction, so inter prediction using the motion information list is not performed. However, when an IBC is executed in an I-slice type slice and a motion information list is available in the IBC, the amvol_enable_flag may be signaled. In addition, when IBC is performed on an I-slice type slice and motion information list prediction is available, amvol_prediction_flag may be signaled.

[00295]

[00296] Next, the motion information list prediction method according to the present invention will be described.

[00297] In the present specification, the current UPU may mean the UPU to which the current block belongs, and the current motion information list may mean the motion information list of the current block.

[00298] In addition, motion information list prediction means motion information prediction to be included in the initialized or newly generated motion information list.

[00299] The motion information of the current motion information list can be predicted using an area in which encoding/decoding is completed earlier than the current UPU (ie, a pre-recovered area).

[00300] Because the image motion information tends to be similar to the spatially and temporally contiguous region, the current UPU may have motion information similar to other spatially and temporally contiguous regions. Therefore, by referring to the motion information in the previously reconstructed area, it is possible to predict the motion information of the motion information list of the current UPU.

[00301] For example, there may be a method for predicting the motion information of the motion information list from an area contiguous in space and time for the current block, and a method for predicting the motion information of the motion information list of the current UPU from the motion information list of the previously recovered UPU.

[00302]

[00303] 1. A method for predicting motion information of a motion information list from a region adjacent in space and time to the current block

[00304]

[00305] It is possible to predict motion information of the current motion information list from areas contiguous in space and time and belonging to UPUs other than the current UPU including the current block.

[00306] FIG. 18 is an example of motion information prediction of the current motion information list from an area adjacent in time to the current block.

[00307] FIG. 18 assumes that the UPU is a picture unit. Therefore, when the picture changes, the motion information list can also be initialized.

[00308] FIG. 18 illustrates a method for predicting motion information of a motion information list (AMOVL) from a reference picture referenced by the current picture. Here, the reference picture is a previously reconstructed picture and may contain motion information used to reconstruct the picture.

[00309] With reference to FIG. 18, motion information can be predicted from a corresponding block (hereinafter referred to as “temporal neighbor block”) of a reference picture that is spatially identical but different in time from the current coding block (e.g., CU, PU, macroblock, CTU, etc.). ) to be encoded/decoded in the current picture and may be added to the current motion information list.

[00310] Since the motion information list is initialized at the point in time when the first coding block of the current picture is restored, there should be no information stored in the motion information list. However, in the example of FIG. 18 to which the present invention is applied, it can be seen that the motion information A', B' and C' outputted from the temporal neighboring blocks of the reference picture is added to the motion information list.

[00311] FIG. 19 is a diagram illustrating an example of motion information prediction of the current motion information list from an area spatially adjacent to the current coding block.

[00312] FIG. 19, the UPU is assumed to be a slice unit. Therefore, there may be multiple UPUs in one picture.

[00313] FIG. 19 shows a motion information prediction method of a motion information list (AMOVL) of a block spatially adjacent to the current coding block (hereinafter referred to as “spatial neighboring block”).

[00314] With reference to FIG. 19, UPU 0 is composed of three blocks, and corresponds to a previously restored area that has already been restored.

[00315] Since the motion information list is initialized at the point in time when the first coding unit UPU 1 is restored, there should be no information stored in the motion information list. However, in the example of FIG. 18 to which the present invention is applied, the motion information of the motion information list can be predicted by referring to the motion information of an area spatially adjacent to the current coding block from the previously recovered UPU 0. Therefore, it can be seen that motion information A and B are added to the list traffic information UPU 1.

[00316] Meanwhile, the description above has been given based on the coding block of FIG. 18 and 19, but may be described in terms of a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), a transform unit (TU), a macroblock, or a predetermined size block.

[00317]

[00318] An encoding block may store motion information in units of subblocks. Accordingly, different motion information can be provided in units of sub-blocks, and the motion information can be accessed regardless of the partition type of the coding block.

[00319] Even in the case of predicting a list of motion information from an area contiguous in space and time, it is possible to refer to a sub-block of the contiguous in space and time of the coding block. Here, since referring to all sub-blocks requires a lot of calculation, motion information list prediction can be performed by referring to a sub-block having a predetermined range or position. A representative value of n sub-blocks may be used instead of the minimum one, so that motion information of all sub-blocks is not stored.

[00320] As an example, when the subblock size is 4×4, four subblocks belong to an 8×8 area. By selecting a representative value from four sub-blocks and storing only one motion information in an 8×8 area, the memory usage for storing sub-block motion information can be reduced. Here, the motion information list prediction may refer to the motion information indicated as representative in the 8×8 region.

[00321] The range for selecting a representative value of the sub-blocks may be set in various sizes such as 4x4, 8x8, 16x16, and the like. The method for selecting a representative value from the sub-blocks may include a method for using a fixed position in the selection range of the representative value, a method for considering the frequency of occurrence, a method for using an average value, and the like. In addition, a representative value may be determined using at least one of a weighted sum, a weighted average, a median, a minimum value, and a maximum value, in addition to the average value.

[00322]

[00323] When predicting a list of motion information from a time-contiguous area, since the picture of the temporal neighbor block is different from the current picture, and the reference picture of the temporal neighbor block is different from the reference picture of the current block, the temporal distance indicated by the motion information may vary.

[00324] For example, in the case where the current picture is POC 4, the temporal neighbor picture referred to for motion information list prediction is POC 8, the reference picture of the current block is POC 8, and the temporal neighbor picture is POC 1 , the temporal distance between the current picture and the current block reference picture has a difference of four with respect to the POC, and the temporal distance between the temporal neighbor picture and the temporal neighbor block reference picture has a difference of seven with respect to the POC. In addition, since the current block refers to the future picture, and the temporal neighbor block refers to the past picture, it can be seen that the temporal directions of reference are also opposite to each other.

[00325] Therefore, it is necessary to predict and correct the change in motion information in time intervals. This is called motion information scaling.

[00326] When motion information list prediction is performed from a time-contiguous area, motion information scaling may also be applied to motion information that is referred to for motion information list prediction.

[00327] Even in the case of predicting a motion information list from a temporal neighbor block, an increase in coding efficiency by scaling the motion information can be expected.

[00328] However, scaling the motion information may be computationally intensive. Therefore, when motion information list prediction is performed, motion information scaling may be omitted, or motion information requiring motion information scaling may not be used for prediction.

[00329] When there is little movement of the temporary neighboring block, scaling of the movement information may not be required.

[00330] Alternatively, motion information scaling may be omitted when the time interval between the current picture and the reference picture of the current block is equal to the time interval between the temporal neighbor block picture and the temporal neighbor block reference picture, or less than a predetermined range.

[00331] As such, only motion information that does not require motion information scaling is used for prediction, and accordingly, an increase in the amount of computation due to motion information scaling can be avoided.

[00332] Meanwhile, motion information requiring motion information scaling may be assigned a lower priority than motion information that does not require motion information scaling in prediction.

[00333]

[00334] 2. A method for predicting motion information of a motion information list from a motion information list of a pre-recovered UPU

[00335]

[00336] The present method is a method for performing motion information list prediction of a current UPU using a motion information list of a previously recovered UPU.

[00337] UPUs may have motion information lists that are different from each other, and spatially and temporally adjacent UPUs may have motion information lists that are similar to each other. Therefore, the current UPU can predict the motion information of the current motion information list by referring to the motion information list of the spatially and temporally adjacent UPU that has been previously recovered.

[00338]

[00339] FIG. 20 is a diagram illustrating an example of a method for performing prediction of the current motion information list with reference to the motion information list of the pre-recovered UPU.

[00340] FIG. 20 shows the point in time when the first coding unit UPU 1 is recovered and the motion information list can be initialized at this point in time so that the motion information generated from the current UPU (UPU 1) cannot be added.

[00341] In the example of FIG. 20 to which the present invention is applied, with reference to the motion information list of the previously recovered UPU 0, motion information list prediction is performed by adding the motion information of the UPU 0 motion information list to the motion information list of the UPU 1.

[00342] After inter-prediction of the first block of the current picture is completed, motion information of the first block may be added to the motion information list. Here, the corresponding motion information may be set to have the lowest index value in the motion information list. The index values of the motion information existing in the existing motion information list may be incremented by one and thus stored.

[00343] Alternatively, the motion information of the first block may be set to have a predetermined index value in the motion information list. The index value of the motion information existing in the existing motion information list may be kept when incremented by one.

[00344]

[00345] Meanwhile, when the entire picture is a UPU, the last block of the previously reconstructed picture is encoded/decoded, and then the final motion information list in which the motion information of the block is stored is used to predict the motion information list of the first block of the current picture.

[00346] That is, all or part of the motion information stored in the final UPU motion information list of the previously recovered picture is used to predict or initialize the motion information list of the current UPU, which is the current picture. Here, the UPU of the previously restored picture may be referred to as the reference UPU.

[00347] The motion information list may not store motion information from the current picture before inter-prediction of the first block of the current picture is performed. This is because there is no motion information in the current picture. Here, the motion information list may be predicted or initialized by storing some or all of the motion information stored in the final motion information list of the reference UPU in the current motion information list. The motion information stored in the current motion information list through prediction or initialization of the motion information list can be used for inter-prediction of the first block of the current picture.

[00348]

[00349] When the current motion information list is predicted from the motion information list of the previously restored area, it is possible to refer to the intermediately configured motion information list instead of the finally configured motion information list in the previously restored area.

[00350] The motion information list may accumulate and store motion information generated in the corresponding UPU, and may also delete the stored motion information. Therefore, as encoding/decoding is performed, the stored information may change. When predicting or initializing the current motion information list, in the case where the location of the coding block to perform prediction by the current motion information list is far from the generation location of the motion information finally stored by the motion information list in the previously reconstructed area referred to by the current motion information list, efficiency motion information list prediction may be reduced.

[00351] For example, when the UPU is a picture unit, the motion information finally stored in the motion information list may be the motion information generated from the bottom right coding block of the picture. Here, when the amount of motion information stored in the motion information list is limited, the motion information generated near the upper left end, which is the initial part of the picture from the finally stored motion information, is removed from the motion information list, and the motion information near the lower right end , which is the end part of the picture, can be stored in the motion information list. Since the first coding block of the current UPU corresponds to the top left picture area, the motion information generated from the bottom right area of the reference picture has a low correlation, and the prediction efficiency is not high. When predicting or initializing the motion information list, coding efficiency may be higher when referring to the motion information list at the time of storing information near the upper left area, instead of the previously restored motion information list that is finally created, than when referring to the final motion information list.

[00352] However, the memory usage is significantly higher when the list of motion information is stored in all stages. Accordingly, after copying and storing a predetermined motion information list at a specific point in time so that memory usage can be reduced, it is possible to separately use a motion information reference list buffer that can be used to predict or initialize the motion information list.

[00353] For example, the motion information lists of the upper left and lower right regions of the UPU may be stored in the reference motion information list buffer.

[00354]

[00355] In addition, when the motion information list of the previously restored picture is used to predict the motion information list, the current picture is different from the previously restored picture, and the reference picture of the current block is different from the reference picture referred to by the motion information in the motion information list of the previously restored picture . Here, since the prediction performance may decrease due to the time distance difference between the previously reconstructed picture and the reference picture referred to by the motion information, correction such as motion information scaling and the like can be used.

[00356]

[00357] In addition, the above-described method may assign a UPU for the call. As a method for assigning a UPU for access, there is a method for allowing an encoder and a decoder to access the same UPU by transmitting and receiving an encoded signal, and a method for skipping additional transmission and receiving a signal by selecting the UPU in a predetermined manner.

[00358] Although in FIG. 20 describes a method of copying the entire motion information list of the reference UPU as a method of predicting the current motion information list, a method of copying only a portion of the motion information from the motion information list to the current motion information list may be applied.

[00359] As an example, only motion information below a predetermined index from the reference UPU's motion information list may be added to the current motion information list.

[00360]

[00361] 3. A method for predicting motion information of the current motion information list from motion information previously included in the current motion information list

[00362]

[00363] When the amount of motion information stored in the motion information list is insufficient, an insufficient amount of the motion information list can be predicted and added from the current motion information list.

[00364] Further prediction of the motion information of the current motion information list from the motion information previously included in the current motion information list may be performed at at least one of the time after the motion information is added to the motion information list, the time that is added, and the time the time at which the motion information is generated in the coding block before the motion information is added to the motion information list.

[00365]

[00366] FIG. 21 is a diagram illustrating a method for performing motion information list prediction from motion information stored in the current motion information list.

[00367] With reference to FIG. 21, it can be seen that the motion information A generated by the inter-prediction of the first coding block is added to the motion information list (AMVOL update). This means a state in which only one motion information is stored in the motion information list. Therefore, when inter-prediction is performed by the motion information list, coding performance may be degraded.

[00368] FIG. 21, it can be seen that motion information list prediction is performed before inter-prediction of the next coding block is performed (or after the motion information list is updated). The amount of motion information stored in the motion information list can be increased by predicting the motion information A' and A'' from the motion information A stored in the current motion information list and storing it in the motion information list. By increasing the amount of motion information in the current motion information list, the performance of inter-prediction using the motion information list can be improved.

[00369]

[00370] Hereinafter, motion information existing in the current motion information list is referred to as existing motion information, and newly predicted motion information is referred to as predicted motion information.

[00371] The following methods 1)-3) are examples of a method for deriving predicted motion information using existing motion information.

[00372]

[00373] 1) Method for transforming motion vector of existing motion information and deriving predicted motion information

[00374]

[00375] The motion vector represents, as motion, the spatial distance between the block using the corresponding motion information and the area to be addressed. Therefore, when the motion vector is converted, the area to be addressed changes.

[00376] For example, there is a method for modifying a motion vector of existing motion information using a predetermined method.

[00377] The motion vector modification method may be at least one of adding offset, scaling, and mirroring.

[00378] Adding an offset is a method of modifying a motion vector by adding a predetermined offset to the motion vector.

[00379] As an example, a motion vector can be expressed as MV(x, y) having an x-axis offset and a y-axis offset, and by adding a predefined offset dx, dy to MV(x, y), a modified vector can be generated movements MV'(x+dx, y+dy). Here, dx and dy can be integers, and dx and dy can be different values.

[00380] Scaling is a method of modifying a motion vector by multiplying a predetermined magnification factor sx and sy by a motion vector MV(x, y). An MV'(sx*x, sy*y) may be generated, which is a motion vector modified by scaling. By using different magnification factors, various modified motion vectors can be generated. Here, sx and sy can be integers, and sx and sy can be different values.

[00381] Mirroring is a method of modifying a motion vector by reversing the direction while maintaining the size of the motion vector. For example, when mirroring the x-axis and y-axis is applied to the motion vector MV(x, y), you can generate MV'(-x, -y) which is the modified motion vector. By specifying the applied axis, various modified motion vectors can be generated.

[00382]

[00383] 2) Method for converting reference information of existing motion information and deriving predicted motion information

[00384]

[00385] The reference information is information about a reference picture including an area that is referred to in inter-prediction. By changing the reference information included in the motion information, the reference picture is changed so that the referenced area can be changed. Even in the case of the same motion vector, when the reference picture changes, the referenced pixel information may change, and thus the inter-prediction result may change. Here, the motion vector is corrected using the distance on the time axis between the current picture and the reference picture of the existing motion information and the distance on the time axis between the current picture and the changed reference picture, thereby improving the motion information prediction accuracy.

[00386] FIG. 22 is an example illustrating the process of deriving the predicted motion information by changing the reference picture of the existing motion information and adjusting the motion vector accordingly.

[00387] With reference to FIG. 22, the current picture is located at point t on the time axis, and the reference picture that can be accessed by the current picture is located at points t-k, t-m, and t+n on the time axis. The current motion information list has motion vector A referring to L0 reference picture 0, which is the reference picture at time t-m with index zero.

[00388] Motion information A can be corrected for the distance (counter picture, POC) on the time axis between the current picture and each reference picture, assuming that the movement of the object is close to linear within a short period of time.

[00389] When the reference information is changed to L0 reference picture 1, which is the reference picture at time t-k, and L1 reference picture 0, which is the reference picture at time t+n, motion information A can be corrected in A' and A '', respectively, taking into account the distance on the time axis between the picture and the reference picture. The predicted motion information outputted in the above manner may be added to the motion information list.

[00390]

[00391] 3) Method for deriving predicted motion information using a plurality of existing motion information

[00392]

[00393] When two or more motion information is present in the motion information list, the predicted motion information may be derived by partially using each of the existing motion information or using the average of the two or more motion information.

[00394] In addition, at least one of statistical values such as weighted sum, weighted average, median, minimum value, maximum value, and the like can be used, in addition to the average.

[00395] Meanwhile, the reference information of any one of the existing motion information may be used as the reference information of the predicted motion information.

[00396] Alternatively, the predicted motion information having reference information different from the reference information of the existing motion information may be output.

[00397] As an example, the reference information may be signaled in the upper parameter set, slice header, or the like, and the picture indicated by the first index of the reference picture list may be used as the reference information of the predicted motion information.

[00398]

[00399] 4. Method for predicting predetermined motion information as motion information of the current motion information list

[00400]

[00401] This method is a method for predicting predetermined motion information as motion information of the current motion information list. Specifically, motion information defined similarly in the encoder and decoder may be added to the current motion information list.

[00402] The predetermined motion information may include motion vector information having a specific motion value in the x and y directions such as (0, 0), (0, 1), (0, -1), (1, 0) , (-1, 0) and the like.

[00403] In addition, the reference information of the predetermined motion information may be determined in advance, for example, the “0”th picture of the reference picture list L0 or the “0”th picture of the reference picture list L1.

[00404] On the other hand, the encoder may generate a flag indicating whether or not to use the predefined motion information and deliver it to the decoder.

[00405] When there is a plurality of predefined motion information, the encoder may generate an identifier (or index, etc.) indicating which motion information should be applied and transmit it to the decoder.

[00406] The decoder may determine whether the predetermined motion information should be applied and which motion information should be applied based on the transmitted information.

[00407]

[00408] There may be a case where there is no pre-restored area that can be accessed by the current UPU, or a case where the amount of motion information that can be predicted from the pre-recovered area that is accessed is sufficient. In such cases, the above methods 3 and 4 can be used to predict the motion information list.

[00409]

[00410] 5. Method for eliminating candidates overlapped by other motion prediction methods

[00411]

[00412] A plurality of inter prediction methods may be used in encoding and decoding, and motion information included in the motion information list may be used to predict motion information in various inter prediction methods. Here, the motion prediction candidate used by the inter-prediction method may be overlapped by the predicted motion information of the motion information list.

[00413] As an example, the motion information of the temporary merge candidate in the merge mode and the motion information predicted for the motion information list are identical and thus overlap with each other.

[00414] In the above case, when using the same motion information for inter-prediction, the prediction performance may deteriorate. Therefore, considering the motion prediction method (eg, merge mode merge candidate, AMVP mode motion vector candidate, etc.) used for inter prediction, the motion information can be set to have more diverse predictive information without overlap.

[00415]

[00416] When the candidates of the motion prediction method and the predicted motion information of the motion information list overlap each other, it can be determined whether to use the predicted motion information of the motion information list according to priority.

[00417] When the priority of motion prediction method candidates is high, the predicted motion information of the motion information list may not be used. That is, the predicted motion information may not be included in the motion information list.

[00418] In contrast, when the priority of the motion prediction method candidates is low, the predicted motion information of the motion information list can be used. That is, the predicted motion information may be included in the motion information list. The motion prediction method candidate may not be included in the motion information list.

[00419] Further, when the priority of the motion prediction method candidates and the priority of the motion information list predicted motion information are the same, the motion information list predicted motion information may be used or may be replaced with predetermined motion information.

[00420]

[00421] In order to prevent the motion prediction information of the motion prediction list and the motion prediction method candidate from overlapping, the predicted motion information list of the motion information list can be set to be output at a predetermined position that does not overlap with the position of the motion prediction method candidate block at the time when encoding/decoding starts.

[00422] For example, a co-located CTU may be assigned and traffic information may be output from a predetermined position in the CTU.

[00423]

[00424] FIG. 23 is a diagram illustrating a motion information list prediction method that does not overlap with a motion prediction method candidate. In FIG. 23, C and H positions indicated by a diagonal pattern (a diagonal pattern from the upper right end to the lower left end) may refer to positions of temporary candidates that may be used in inter-prediction of the current coding block.

[00425] With reference to FIG. 23, the previously reconstructed area used for motion information list prediction may be set to an area at a position different from the positions C and H.

[00426] As shown in FIG. 23, the motion information of the motion information list can be set to be output at positions a, b, c, d, and e except for positions C and H.

[00427] In addition, when motion information is added to the motion information list, the same motion information as the motion information of positions C or H cannot be added to the motion information list.

[00428] FIG. 24 is a diagram illustrating an embodiment of setting a position referenced for motion information list prediction in CTUs when the positions of the temporal candidates of the motion prediction method are the same as the positions C and H in FIG. 23.

[00429] When configuring the reference position in CTU units in the same manner as in FIG. 24, it is possible to simplify the motion information list prediction structure using a fixed position while improving coding efficiency by referring to an area not predicted by the existing motion prediction method.

[00430] FIG. 24, the diagonal pattern block (diagonal pattern block from top right to bottom left) and the reverse diagonal pattern block (diagonal pattern block from top left to bottom right) may indicate the positions of motion information that is referred to for predicting the current motion information list in the co-located CTU. A diagonal pattern block means a reference area having a higher priority than a reverse diagonal pattern block.

[00431]

[00432] Meanwhile, when the motion prediction candidate used by the inter-prediction method is overlapped by the motion information list prediction motion information, the overlapped motion information cannot be used for inter-prediction.

[00433]

[00434] 6. Method for using predicted motion information separately from general motion information

[00435]

[00436] In the present specification, the general motion information may mean motion information added to the motion information list as motion information generated by inter prediction and motion information added to the motion information list in the motion information adding step of FIG. 10 and 11. The predicted motion information may mean motion information generated by motion information list prediction as described above, and may be motion information added to the motion information list in the motion information list prediction steps of FIG. 10 and 11.

[00437]

[00438] The predicted motion information may have a lower motion information prediction performance than the general motion information. Therefore, when the predicted motion information has a higher priority than the general motion information, the coding efficiency may be lowered. Therefore, the predicted motion information may be generated separately from the general motion information, so that the priority of the predicted motion information may be reduced or corrected.

[00439] In addition, in case general motion information is added when the motion information list already had a limited maximum amount of motion information, the predicted motion information may be removed first.

[00440]

[00441] FIG. 25 and 26 are diagrams illustrating an embodiment of a method for separately using predicted motion information and common motion information. The motion information may be added to the motion information list in FIG. 25 and 26 on a first-come-first-served (FIFO) basis, and the size of the motion information list is limited to five. Here, the size of the motion information list also includes the size of the motion sub-list.

[00442] With reference to FIG. 25, there may be a motion information list (AMVOL) storing general motion information and a motion information sub-list (sub-AMVOL) storing a list of predicted motion information.

[00443] Prior to performing inter-prediction of the first coding block, no information is stored in the motion information list, and motion information A', B', and C' predicted from the reference picture may be stored in the motion information sub-list.

[00444] Then, motion information may be added to the motion information list as inter-prediction of each coding block is performed.

[00445] Here, when the maximum size of the motion information list is reached, the motion information is first removed from the motion information sub-list in which the predicted motion information is stored, and new motion information may be added to the motion information list.

[00446] Meanwhile, information indicating whether the motion information sub-list, motion information list size information, or motion information sub-list size information is used may be information preset in the encoder/decoder.

[00447] Alternatively, information indicating whether the motion information sub-list, motion information list size information, or motion information sub-list size information is used may be information signaled from an encoder to a decoder.

[00448] Here, the size of the motion information list may be limited to a predetermined range. For example, the preset range could be 0 to 5.

[00449] In addition, the size of the motion information list may be limited by the information signaled from the encoder to the decoder. Information indicating the size of the motion information list may be signaled at a higher bitstream level such as a sequence parameter set, a picture parameter set, a slice header, a tile header, a tile group header, and the like.

[00450]

[00451] FIG. 26 is a diagram illustrating an embodiment in which one motion information list is used without using a motion information sub-list, unlike FIG. 25.

[00452] In the example of FIG. 26, the motion information list may be controlled in a FIFO manner. That is, the motion information list uses a method of adding the generated motion information to the last part of the motion information list and deleting first the preceding motion information which is inputted first when the maximum size of the motion information list is exceeded.

[00453] In other words, when the amount of motion information stored in the motion information list reaches the maximum value, the motion information specified in the last index of the motion information list is deleted, and the newly derived motion information is added to the motion information list. Here, the index of the motion information included in the motion information list may be incremented by one. The newly added motion information may be added to the motion information list so as to be indicated by index 0.

[00454]

[00455] In addition, the motion information stored in the motion information list may be given higher priority as the index is lower.

[00456] Here, the motion information stored by the motion information list prediction may be processed separately from the general motion information of the motion information list generated and stored in the current UPU.

[00457] Because the predicted motion information has a low priority, when the general motion information is added again, an index lower than in the case of the motion information in the predicted motion information list may be assigned.

[00458] In addition, when the maximum size of the motion information list is reached, the predicted motion information may be preferably deleted, and new motion information may be added to the motion information list.

[00459]

[00460] In this case, the lower the index, the higher the priority, as described earlier. On the contrary, the higher the index, the lower the priority.

[00461] Therefore, the FIFO method for the motion information list may also be performed as described later. That is, when the amount of motion information stored in the motion information list reaches the maximum value, motion information indicated by index 0 of the motion information list may be deleted, and newly outputted motion information may be added to the motion information list. Here, the index of the motion information included in the motion information list may decrease by one. The newly added motion information may be added to the motion information list so as to be indicated by the largest index among the motion information included in the motion information list.

[00462] Meanwhile, when the newly added motion information is stored in the motion information list, the previously stored motion information that overlaps is removed from the motion information list, and the newly derived motion information can be included in the motion information list. Here, the motion information indexes of the motion information list having an index value greater than the deleted motion information may decrease by one. The newly added motion information may be added to the motion list so as to be indicated by the largest index among the motion information included in the motion information list.

[00463]

[00464] Motion information included in the motion information list may be prioritized when used to predict motion information. The motion information may be implicitly expressed according to the order in which the motion information is stored in the motion information list, the priority is explicitly set as candidates when performing inter-prediction using the motion information list, or selective use by priority is possible.

[00465] In addition, since the motion information list may have a limited size, when the limited size is reached, motion information stored in the motion information list may be deleted and new motion information may be added according to priority.

[00466]

[00467] Meanwhile, the predicted motion information may have a prediction performance lower than the prediction performance of the normal motion information. However, since this is not the case in all cases, the priority of the predicted motion information can be reset.

[00468]

[00469] Additional information may be used to re-prioritize the predicted motion information.

[00470] The motion information list may include additional information in addition to the motion information. Here, the side information may mean information indicating the inter-prediction performance of the motion information included in the motion information list, and may also be referred to as potential prediction information. For example, the additional information may be information derived based on the number of occurrences of the same motion information in the UPU.

[00471] The side information may represent the relative variability in coding efficiency when using a list of motion information for inter-prediction.

[00472] As a method for determining the additional information, there may be a determination method based on the occurrence frequency of the motion information, a determination method based on the prediction performance using the motion information, a determination method based on the location where the motion information is output, and a determination method based on whether whether to use motion information.

[00473] The determination method based on the frequency of occurrence of motion information is a method for determining additional information based on the number of times the same motion information as the motion information stored in the motion information list is generated in the UPU.

[00474] The determination method based on the prediction efficiency using motion information is a method for determining side information based on the residual signal energy distribution or the average value of the residual signal energy in a coding block using motion information stored in the motion information list.

[00475] The determination method based on the location from which motion information is derived is a method for determining additional information based on the spatial and temporal distance between the current coding block and the coding block in which the motion information stored in the motion information list is derived.

[00476] At the same time, the priority of the predicted motion information may be reset based on whether the predicted motion information is used for inter-prediction. The reason is that the corresponding predicted motion information is likely to be used in the future when it is used for inter-prediction.

[00477] The information necessary to reset the priority of the predicted motion information may be information that is preset in the encoder/decoder or signaled from the encoder to the decoder.

[00478]

[00479] FIG. 27 is a flowchart illustrating an image decoding method according to an embodiment of the present invention.

[00480] With reference to FIG. 27, the image decoding apparatus may generate a candidate list including motion information derived from the spatial neighbor block and the temporal neighbor block adjacent to the current block (S2710).

[00481] Here, the candidate list can be any one of the merge mode merge candidate list, the AMVP mode motion vector candidate list, the IBC mode merge candidate list, the IBC mode block vector candidate list, and the shared IBC mode merge list .

[00482] In addition, the image decoding apparatus may output motion information of the current block using the candidate list (S2720).

[00483] The image decoding apparatus may generate a prediction block of the current block using the derived motion information (S2730). In detail, the image decoding apparatus may generate a prediction block of the current block by performing inter-prediction or IBC prediction.

[00484] In addition, the image decoding apparatus may update the outputted motion information in the motion information list (S2740). Step S2740 may be the same as the step of adding motion information in FIG. 10 and 11 described above.

[00485] This may generate a candidate list including at least one of the motion information included in the motion information list updated in the block decoded before the current block. Here, the motion information list may be the above-described AMVOL or HMVP list.

[00486] Meanwhile, when the decoding of the predetermined area is completed so that the area in the motion information list is changed, the image decoding apparatus may initialize the motion information list. Here, the predefined area may be any one of a block consisting of one or more CUs, or a block consisting of one or more CTUs. The above-described initialization may be the same as the motion information initialization step in FIG. 10 and 11.

[00487] Meanwhile, the motion information list may have a predetermined size limit. Here, the predetermined size may be six.

[00488] Meanwhile, when there is a plurality of motion information in the motion information list updated in the block decoded before the current block, the picture decoding apparatus may include an average of at least two or more motion information from the plurality of motion information in the candidate list.

[00489] Meanwhile, when the motion information of the motion information list updated in the block decoded before the current block is the same as the motion information previously included in the candidate list, the picture decoding apparatus may allow not to include the motion information of the motion information list to the list of candidates.

[00490] In addition, when the current block is the IBC prediction mode and the candidate list is a shared merge list, the method of updating the outputted motion information in the motion information list may be omitted.

[00491] Meanwhile, when the amount of motion information stored in the motion information list is a preset value, the image decoding apparatus may delete the motion information stored first in the motion information list and store the motion information outputted in step S2720.

[00492] The image decoding method has been described above with reference to FIG. 27. Since the image encoding method of the present invention can be described similarly to the image decoding method described with reference to FIG. 27, the redundant description is omitted.

[00493] The bit stream generated by the image encoding method of the present invention may be temporarily stored in a computer-readable durable recording medium, and may be decoded by the image decoding method described above.

[00494]

[00495] The above embodiments may be performed in the same manner in the encoder and decoder.

[00496] At least one or a combination of the above embodiments may be used for video encoding/decoding.

[00497] The sequence applied to the above embodiment may be different for the encoder and decoder, or the sequence applied to the above embodiment may be the same in the encoder and decoder.

[00498] The above embodiment may be performed for each luminance signal and chrominance signal, or the above embodiment may be identically performed for luminance and chrominance signals.

[00499] The shape of the block to which the above embodiments of the present invention apply may be square or non-square.

[00500] The above embodiment of the present invention may be applied depending on the size of at least one of a coding block, a prediction block, a transform block, a block, a current block, a coding unit, a prediction unit, a transform unit, a unit, and a current unit. Here, the size may be defined as a minimum size or a maximum size, or both, to apply the above embodiments, or may be defined as a fixed size to which the above embodiment is applied. In addition, in the above embodiments, the first embodiment may be applied to the first dimension, and the second embodiment may be applied to the second dimension. In other words, the above embodiments may be applied in combination depending on the size. In addition, the above embodiments can be applied when the size is equal to or greater than the minimum size and equal to or less than the maximum size. In other words, the above embodiments can be applied when the block size falls within a certain range.

[005001] For example, the embodiments described above may be applied when the current block size is 8×8 or larger. For example, the above embodiments may be applied when the current block size is 4×4 or larger. For example, the embodiments described above may be applied when the current block size is 16×16 or larger. For example, the above embodiments may be applied when the size of the current block is equal to or greater than 16×16 and equal to or less than 64×64.

[00502] The above embodiments of the present invention may be applied depending on the temporal level. In order to identify the temporal layer to which the above embodiments may apply, a corresponding identifier may be signaled, and the above embodiments may apply to the indicated temporal layer identified by the corresponding identifier. Here, the identifier may be defined as the lowest level or the highest level, or both, to which the above embodiment may apply, or may be defined to indicate the specific level to which this embodiment applies. In addition, a fixed time level to which the embodiment applies can be determined.

[00503] For example, the embodiments described above may be applied when the temporal level of the current image is the lowest level. For example, the above embodiments can be applied when the temporal level identifier of the current picture is equal to or greater than 1. For example, the above embodiments can be applied when the temporal level of the current picture is the highest level.

[00504] The slice type or tile group type to which the above embodiments of the present invention apply can be determined, and the above embodiments can be applied depending on the corresponding slice type or tile group type.

[00505] In the above embodiments, the methods are described based on flowcharts with a sequence of steps or modules, but the present invention is not limited to the order of the steps, and rather, some steps may be performed simultaneously or in a different order with other steps. In addition, one skilled in the art will appreciate that the steps in the flowcharts are not mutually exclusive and that other steps may be added to the flowcharts, or some of the steps may be removed from the flowcharts. operations without affecting the scope of the present invention.

[00506] Embodiments include various aspects of the examples. All possible combinations for various aspects may not be described, but those skilled in the art will recognize various combinations. Accordingly, the present invention may include all substitutions, modifications and changes within the scope of the claims.

[00507] Embodiments of the present invention may be implemented in the form of program instructions that are executed by various computer components and recorded on a computer-readable recording medium. The computer-readable recording medium may include, individually or in combination, program instructions, data files, data structures, and so on. The program instructions recorded on a computer-readable recording medium may be specially designed and constructed for the present invention, or well known to those skilled in the art of computer program technology. Examples of computer-readable recording media include magnetic recording media such as hard disks, floppy disks, and magnetic tapes; optical storage media such as CD-ROM or DVD-ROM; magneto-optical media such as floppy disks; and hardware devices such as read only memory (ROM), random access memory (RAM), flash memory, etc., which are specifically structured to store and implement a program instruction. Examples of program instructions include not only mechanical language code formatted by a compiler, but high-level language code that can be implemented by a computer using an interpreter. The hardware devices may be configured to operate with one or more software modules or, conversely, to perform processes in accordance with the present invention.

[00508] Although the present invention has been described in terms of specific subjects such as detailed elements as well as limited embodiments and drawings, they are provided only to facilitate a more general understanding of the invention, and the present invention is not limited to the above embodiments. Those skilled in the art to which the present invention pertains will appreciate that various modifications and changes may be made based on the above description.

[00509] Therefore, the scope of the present invention should not be limited to the embodiments described above, and the entire scope of the appended claims and their equivalents will be within the scope and spirit of the invention.

Industrial Applicability

[00510] The present invention can be used to encode or decode an image.

Claims (42)

1. A method for generating a candidate list of motion information generated during image decoding, comprising: generating a candidate list including motion information generated using neighboring block information adjacent to the current block; outputting movement information of the current block using the candidate list; generating a prediction block of the current block using the derived second motion information of the current block; and updating the motion information list to store the derived motion information of the current block, wherein the candidate list includes at least one of the motion information included in the motion information list used for the block being decoded before decoding for the current block. 2. The method of claim 1, wherein the motion information list is initialized when decoding of the predetermined area is completed, so that the area is changed. 3. The method of claim 2, wherein the predefined region is any one of a one or more coding tree unit (CU) or a one or more coding tree unit (CTU). 4. The method of claim 1, wherein when there is a plurality of motion information in the motion information list used for a block being decoded before decoding for the current block, generating the candidate list is performed to include an average of at least two or more motion information from set of motion information in the list of candidates. 5. The method of claim 1, wherein when the motion information of the motion information list used for the block being decoded before decoding for the current block is the same as the motion information previously included in the candidate list, generation of the candidate list is performed as follows not to include this traffic information list traffic information in the list of candidates. 6. The method of claim 1, wherein when the prediction mode for the current block is intra-block copy (IBC) mode and the candidate list is a shared merge list, updating the motion information list is omitted. 7. The method according to claim 1, wherein the outputted motion information for the current block is stored in the motion information list for use for the intra-block copy (IBC) mode when the size of the current block is greater than or equal to the first predetermined size and this size is less than or equal to the second predetermined size. 8. The method of claim 1, wherein when the amount of motion information stored in the motion information list is a predetermined value, updating the outputted motion information in the motion information list includes deleting the motion information stored first in the motion information list and storing the outputted movement information. 9. A method for generating a candidate list of motion information generated when encoding an image, comprising: generating a candidate list including motion information generated using neighboring block information adjacent to the current block; outputting movement information of the current block using the candidate list; generating a prediction block of the current block using the derived motion information of the current block; and updating the motion information list to store the derived motion information of the current block, wherein the candidate list includes at least one information from the motion information included in the motion information list used for the block being encoded before encoding for the current block. 10. The method of claim 9, wherein the motion information list is initialized when encoding of the predetermined area is completed so that the area is changed. 11. The method of claim 10, wherein the predefined region is any one of a one or more coding tree unit (CU) or a one or more coding tree unit (CTU). 12. The method of claim 9, wherein when there is a plurality of motion information in the motion information list used for the block being encoded before encoding for the current block, generating the candidate list is performed to include an average of at least two or more motion information from set of motion information in the list of candidates. 13. The method of claim 9, wherein when the motion information of the motion information list used for the block being encoded before encoding for the current block is the same as the motion information previously included in the candidate list, generation of the candidate list is performed as follows not to include this traffic information list traffic information in the list of candidates. 14. The method of claim 9, wherein when the prediction mode for the current block is intra-block copy (IBC) mode and the candidate list is a shared merge list, updating the motion information list is omitted. 15. The method of claim 9, wherein the outputted motion information for the current block is stored in a motion information list for use for intra-block copy (IBC) mode when the size of the current block is greater than or equal to the first predetermined size and that size is less than or equal to the second predetermined size. 16. The method of claim 9, wherein when the amount of motion information stored in the motion information list is a predetermined value, updating the outputted motion information in the motion information list includes deleting the motion information stored first in the motion information list and storing the outputted movement information. 17. A computer-readable recording medium comprising a bitstream decoded by an image decoding method, the image decoding method comprising: generating a candidate list including motion information generated using neighboring block information adjacent to the current block; outputting movement information of the current block using the candidate list; generating a prediction block of the current block using the derived motion information of the current block; and updating the motion information list to store the derived motion information of the current block, wherein the candidate list includes at least one information from the motion information included in the motion information list used for the block being decoded before decoding for the current block. 18. The computer-readable recording medium of claim 17, wherein the derived motion information for the current block is stored in the motion information list to be used for the intra-block copy (IBC) mode when the size of the current block is greater than or equal to the first predetermined size. 19. A computer-readable recording medium containing a bitstream, and the bitstream contains: information for the prediction mode, while prediction for the current block is performed using the information for the prediction mode, a candidate list including motion information generated using neighboring block information adjacent to the current block is generated; the movement information of the current block is output using the list of candidates, a prediction block of the current block is generated using the derived motion information of the current block, the motion information list is updated to store the output motion information of the current block, and wherein the candidate list includes at least one information from the motion information included in the motion information list used for the block being decoded before decoding for the current block. 20. The computer-readable recording medium of claim 19, wherein the derived motion information for the current block is stored in the motion information list to be used for the intra-block copy (IBC) mode when the size of the current block is greater than or equal to the first predetermined size.

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