WO2019194499A1

WO2019194499A1 - Inter prediction mode-based image processing method and device therefor

Info

Publication number: WO2019194499A1
Application number: PCT/KR2019/003805
Authority: WO
Inventors: 장형문; 남정학; 박내리
Original assignee: 엘지전자 주식회사
Priority date: 2018-04-01
Filing date: 2019-04-01
Publication date: 2019-10-10

Abstract

Disclosed are a method for performing decoding of a video signal and a device therefor. Particularly, a method for processing an image on the basis of an inter prediction mode may comprise the steps of: determining whether a spatial neighboring block of a current block is available; when the spatial neighboring block is available as a result of the determination, adding motion information of the available spatial neighboring block to a motion information candidate list; determining whether a temporal neighboring block of the current block is available; when the temporal neighboring block is available as a result of the determination, adding motion information of the available temporal neighboring block to the motion information candidate list; selecting a candidate used for intra prediction of the current block from the motion information candidate list; and generating a prediction block of the current block by using the selected candidate.

Description

[Specifications

[Name of invention]

Inter prediction mode based image processing method and apparatus therefor

Technical Field

The present invention relates to a still image or moving image processing method, and more particularly, to a method for encoding / decoding a still image or moving image based on an inter prediction mode, and an apparatus supporting the same.

Background Art

Compression coding refers to a series of signal processing techniques for transmitting digitized information through a communication line or for storing in a form suitable for a storage medium. Media such as an image, an image, an audio, and the like may be a target of compression encoding. In particular, a technique of performing compression encoding on an image is called video image compression. Next-generation video content will be characterized by high spatial resolution, high frame rate and high dimensionality of scene representation. Processing such content will result in a tremendous increase in terms of memory storage, memory access rate, and processing power.

Therefore, there is a need to design a coding framework for more efficiently processing next generation video content.

[Detailed Description of the Invention]

[Technical problem] An object of the present invention is to propose a method for constructing a spatial candidate list in order to use motion information of neighboring blocks of a current block for prediction.

It is also an object of the present invention to propose a method of constructing temporal candidates in order to use motion information of neighboring blocks of a current block for prediction.

It is also an object of the present invention to propose a method of saving signaling bits by rearranging the order of candidate lists.

It is also an object of the present invention to propose a method for selecting candidates based on a reordered candidate list without additional syntax signaling.

It is also an object of the present invention to use particular candidates in a reordered candidate list

We propose a method for deriving ATMVP.

It is also an object of the present invention to propose a method of constructing a candidate list by filling in the number of allowed candidates based on rearranged candidates.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

Technical Solution

An aspect of the present invention provides a method of processing an image based on an inter prediction mode, the method comprising: checking whether a spatial neighboring block of a current block is available; If the spatial neighboring block is available as a result of the checking, motion information of the available spatial neighboring block is added to the motion information candidate list. Adding step; Checking whether a time (61 0 31) neighboring block of the current block is available; Adding the motion information of the available time neighboring block to the motion information candidate list if the time neighboring block is available as a result of the checking; Selecting a candidate used for intra prediction of the current block from the motion information candidate list; And generating a prediction block of the current block by using the selected candidate.

Preferably, adding the motion information of the temporal neighboring block to the motion information candidate list further comprises: adding a subblock-based temporal candidate to the motion information candidate list, The sub-block based temporal candidate uses a sub-block using motion information of a reference block specified by a first candidate of a motion information candidate list to which motion information of the spatial neighboring block is added in a reference picture of the current block. Can be derived in units.

Preferably, adding the motion information of the temporal neighboring block to the motion information candidate list includes rearranging the motion information candidate list to which the motion information of the spatial neighboring block is added based on a cost value of each candidate. reordering; And stocking a sub-block based temporal candidate to the motion information candidate list, wherein the sub-block based temporal candidate is within the reference picture of the current block, the reordered The motion information of the reference block specified by the first candidate of the motion information candidate list may be derived in sub-block units. 0 2019/194499 1 »（: 1/10 公 019/003805

4 preferably, reordering the motion information candidate list to which the motion information of the spatial neighboring block and the temporal neighboring block is added based on a cost value of each candidate; And stocking a sub-block based temporal candidate to the motion information candidate list, wherein the sub-block based temporal candidate is the reordered motion within a reference picture of the current block. The motion information of the reference block specified by the first candidate of the information candidate list may be derived in sub-block units.

Preferably, the motion information candidate list may be rearranged based on the cost value of the candidate included in the motion information candidate list whenever each candidate is added.

Preferably, reordering the motion information candidate list to which the motion information of the spatial neighboring block and the temporal neighboring block is added based on the cost value of each candidate; And generating a final motion information candidate list by using the maximum number of candidates and candidates based on priority in the rearranged motion information candidate list, and selecting a candidate used for intra prediction of the current block. May be performed by selecting a candidate used for intra prediction of the current block from the final motion information candidate list.

According to another aspect of the present invention, in an apparatus for processing an image based on an inter prediction mode, confirming whether a spatial neighboring block of a current block is available, and if the spatial neighboring block is available as a result of the checking, Use of the above A spatial candidate inserter that adds motion information of possible spatial neighboring blocks to a motion information candidate list; A time candidate for checking whether a temporal neighboring block of the current block is available and adding the motion information of the available time-out block to the motion information candidate list if the temporal neighboring block is available as a result of the checking; Insert; A candidate selector for selecting a candidate used for intra. Prediction of the current block from the motion information candidate list; And a prediction block generator for generating a prediction block of the current block by using the selected candidate.

Preferably, the temporal candidate inserter adds a subblock-based temporal candidate to the motion information candidate list, wherein the sub-block based temporal candidate is within a reference picture of the current block. The motion information of the spatial neighboring block may be derived in units of sub-blocks using motion information of the reference block specified by the first candidate of the motion information candidate list to which the motion information is added.

Preferably, the temporal candidate inserter reorders the motion information candidate list to which motion information of the spatial neighboring block is added based on a cost value of each candidate, and sub-block based time candidates. add a subblock-based temporal candidate to the motion information candidate list, and the sub-block based temporal candidate is specified by a first candidate of the rearranged motion information candidate list within a reference picture of the current block. It may be derived in sub-block units using motion information of the reference block. Preferably, the rearrangement unit for reordering the motion information candidate list to which the motion information of the spatial neighboring block and the temporal neighboring block is added based on the cost value of each candidate; And a sub-block-based temporal candidate inserter for adding a sub-block-based temporal candidate to the motion information candidate list, wherein the sub-block-based temporal candidate is a reference picture of the current block. The motion information of the reference block specified by the first candidate of the rearranged motion information candidate list may be derived in sub-block units.

Preferably, the rearrangement unit for reordering the motion information candidate list to which the motion information of the spatial neighboring block and the temporal neighboring block is added based on the cost value of each candidate; And a final candidate list generator configured to generate a final motion information candidate list by using the maximum number of candidates based on priority in the rearranged motion information candidate list, wherein the candidate selector comprises: the final motion information. In the candidate list, a candidate used for intra prediction of the current block may be selected.

Advantageous Effects

According to the embodiment of the present invention, by rearranging the candidates based on similarity, a relatively small baht can be allocated to a candidate having a higher selection probability, thereby increasing compression efficiency. In addition, according to an embodiment of the present invention, motion information with high similarity may be derived by deriving an advanced temporal motion vector prediction (ATMVP) candidate based on the rearranged candidate list, thereby increasing the accuracy of prediction.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. .

[Brief Description of Drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical features of the present invention.

1 is a schematic block diagram of an encoding apparatus in which an encoding of a video / image signal is performed, according to an embodiment to which the present invention is applied.

2 is a schematic block diagram of a decoding apparatus in which decoding of a video / image signal is performed according to an embodiment to which the present invention is applied.

3 is a diagram illustrating an example of a multi-type tree structure as an embodiment to which the present invention can be applied.

FIG. 4 is a diagram illustrating a signaling mechanism of partition partitioning information of a quadtree with nested mult-type tree structure with a multitype tree according to an embodiment to which the present invention may be applied.

FIG. 5 is an embodiment to which the present invention can be applied, based on a quadtree and a accompanying multi-type tree structure Is a diagram illustrating a method of dividing 11 into multiple 0's.

FIG. 6 is a diagram illustrating a method of limiting ternary-tree partitioning as an embodiment to which the present invention may be applied.

FIG. 7 is a diagram illustrating redundant division patterns that may occur in binary tree division and ternary tree division as an embodiment to which the present invention may be applied.

8 ^and, 9 is a diagram illustrating inter-prediction unit in the encoding device according to the way inter-prediction-based video / image encoding according to an embodiment of the present invention and embodiments of the invention.

10 and 11 illustrate an inter prediction based video / image decoding method and an inter prediction unit in a decoding apparatus according to an embodiment of the present invention.

FIG. 12 is a diagram for describing a neighboring block used in a merge mode or a skip mode as an embodiment to which the present invention is applied.

13 is a flowchart illustrating a merge candidate list construction method according to an embodiment to which the present invention is applied.

14 is a flowchart illustrating a merge candidate list construction method according to an embodiment to which the present invention is applied.

15 and 16 are diagrams for explaining a method of deriving an Advanced Temporal Motion Vector Prediction (ATMVP) candidate according to an embodiment to which the present invention is applied.

FIG. 17 illustrates an ATMVP (Advanced Temporal) according to an embodiment to which the present invention is applied. A diagram illustrating a method of deriving a motion vector prediction candidate. 18 and 19 are diagrams illustrating a method of compressing temporal motion vector data and positions of spatial candidates used therein according to an embodiment to which the present invention is applied.

20 is a flowchart illustrating a method of constructing a candidate list using motion information of spatial neighboring blocks according to an embodiment to which the present invention is applied.

21 is a flowchart illustrating a method of constructing a candidate list using motion information of a temporal neighboring block according to an embodiment to which the present invention is applied.

FIG. 22 is a flowchart illustrating a method of deriving motion information used for motion compensation in a candidate list based on a syntax element transmitted through a bit stream as an embodiment to which the present invention is applied.

FIG. 23 is a flowchart illustrating a method of deriving motion information used for motion compensation in a candidate list without a syntax element transmitted through a bit stream as an embodiment to which the present invention is applied.

24 is a flowchart illustrating a method of constructing a motion information candidate list using a spatial candidate and a temporal candidate and reordering candidates of the configured candidate list according to an embodiment to which the present invention is applied. .

FIG. 25 is a flowchart illustrating a method of constructing a motion information candidate list using a spatial candidate and a temporal candidate and rearranging candidates of the configured candidate list according to an embodiment to which the present invention is applied.

FIG. 26 illustrates a method for rearranging candidates in a candidate list constructed using a spatial candidate and a temporal candidate as an embodiment to which the present invention is applied. 2019/194499 1 »（： 1 ^ 1 {2019/003805

10 flow chart.

FIG. 27 is a flowchart illustrating a method of rearranging candidates in a candidate list constructed using a spatial candidate and a temporal candidate as an embodiment to which the present invention is applied.

FIG. 28 is a diagram to illustrate a method of constructing a candidate list in consideration of the maximum allowable number of candidates according to an embodiment to which the present invention can be applied.

29 is a diagram illustrating a candidate list generation method according to an embodiment to which the present invention is applied.

30 is a diagram illustrating a candidate list generation method according to an embodiment to which the present invention is applied.

31 is a diagram illustrating a method of performing motion compensation based on a candidate list configured according to an inter prediction mode according to an embodiment to which the present invention is applied.

32 is a flowchart illustrating a method of generating an inter prediction block according to an embodiment to which the present invention is applied.

33 is a diagram illustrating an inter prediction apparatus according to an embodiment to which the present invention is applied.

34 shows a video coding system to which the present invention is applied.

35 is a diagram illustrating the structure of a content streaming system according to an embodiment to which the present invention is applied.

[Form for implementation of invention]

Hereinafter, with reference to the accompanying drawings, preferred embodiments according to the present invention. 2019/194499 1 »（： 1 ^ 1 {2019/003805

11 Details. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

In addition, the terminology used in the present invention was selected as a general term widely used as possible now, in a specific case will be described using terms arbitrarily selected by the applicant. In such a case, since the meaning is clearly described in the detailed description of the part, it should not be interpreted simply by the name of the term used in the description of the present invention, and it should be understood that the meaning of the term should be understood and interpreted. .

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention. For example, signals, data, samples, pictures, frames, blocks, etc. may be appropriately replaced and interpreted in each coding process.

Hereinafter, in the present specification, ^one processing unit ¹ refers to a unit in which a processing of encoding / decoding such as prediction, transformation, and / or quantization is performed. Hereinafter, for convenience of description, the processing unit is ^| May be referred to as a processing block or block. The processing unit may be interpreted to include a unit for the luma component and a unit for the chroma component. For example, the processing unit may correspond to a Coding Tree Unit (CTU), a Coding Unit (CU), that is, a Prediction Unit (PU) or a Transform Unit (TU).

In addition, the processing unit may be interpreted as a unit for the luma component or a unit for the chroma component. For example, the processing unit may be a Coding Tree Block (CTB), Coding Block (CB), Prediction Block (PU) or Transform Block (TB) for a luma component. May correspond to. Or, it may correspond to a coding tree block (CTB), a coding block (CB), a prediction block (PU), or a transform block (TB) for a chroma component. In addition, the present invention is not limited thereto, and the processing unit may be interpreted to include a unit for a luma component and a unit for a chroma component.

In addition, the processing unit is not necessarily limited to square blocks,

It may be configured in the form of a polygon having three or more vertices.

In the following specification, a pixel, a pixel, and the like are referred to collectively as a sample. In addition, using a sample may mean using a pixel value or a pixel value.

Referring to FIG. 1, the encoding apparatus 100 may include an image splitter 110, a subtractor 115, Transformer 120, Quantizer 130, Inverse Quantizer 140, Inverse Transformer 150, Adder 155, Filter 160, Memory 170, Inter Predictor 180, Intra And a predictor 18eng and an entropy encoding unit 190. The inter predictor 180 and the intra predictor 18 引 may be collectively referred to as a predictor. 180 and an intra predictor 185. The transformer 120, the quantizer 130, the inverse quantizer 140, and the inverse transformer 150 may be included in the residual processing unit. The residual processing unit may further include a subtracting unit 115. As an example, the above-described image segmentation unit 110, subtraction unit 11, conversion unit 120, quantization unit 130, and inverse The quantizer 140, the inverse transformer 150, the adder 155, the filter 160, the inter predictor 180, the intra predictor 18 ¼, and the entropy encoder 190 are provided as one hardware component ( Example For example, the encoder 17 may include a decoded picture buffer (DPB) or a digital storage medium.

The image divider 110 may divide an input image (or a picture or a frame) input to the encoding apparatus 100 into one or more processing units. For example, the processing unit may be called a coding unit (CU). In this case, the coding unit may be recursively divided according to a quad-tree binary-tree (QTBT) structure from a coding tree unit (CTU) or a largest coding unit (LCU). For example, one coding unit may be divided into a plurality of coding units of a deeper map based on a quad tree structure and / or a binary tree structure. in this case For example, the quad tree structure can be applied first and the binary tree structure can be applied later. Alternatively, the binary tree structure may be applied first. The coding procedure according to the present invention may be performed based on the final coding unit that is no longer split. In this case, based on the coding efficiency according to the image characteristic, the maximum coding unit may be used as the final coding unit, or if necessary, the coding unit is recursively divided into coding units of lower maps, rather than optimally. A coding unit of size may be used as the final coding unit. Here, the coding procedure may include a procedure of prediction, transform, and reconstruction, which will be described later. As another example, the processing unit may further include a Prediction Unit (PU) or a Transform Unit (TU). In this case, the prediction unit and the transform unit may be partitioned or partitioned from the aforementioned final coding unit, respectively. The prediction unit may be a unit of sample prediction, and the transformation unit may be a unit for deriving a transform coefficient and / or a unit for deriving a residual signal from the transform coefficient.

The unit may be used interchangeably with terms such as block or area as the case may be. In a general case, an MXN block may represent a set of samples or transform coefficients composed of M columns and N rows. A sample may generally represent a pixel or a value of a pixel, and may only represent pixel / pixel values of the luma component or only pixel / pixel values of the chroma component. A sample may be used as a term corresponding to one picture (or image) for a pixel or pel.

The encoding device (100) is used for input video signal (original block, original sample array) A residual signal (residual block, residual sample array) may be generated by subtracting a prediction signal (a predicted block, ie, a sample array) output from the inter predictor 180 or the intra predictor 185, The generated residual signal is transmitted to a transform unit 12. In this case, as illustrated, the prediction signal (prediction block, prediction sample array) is subtracted from the input video signal (original block, original sample array) in the encoder 100. The unit to perform may be referred to as a subtractor 115. The predictor performs a prediction on a block to be processed (hereinafter, referred to as a current block), and includes a predicted block including examples, that is, samples for the current block. The prediction unit may determine whether intra prediction or inter prediction is applied on a current block or CU basis. As described below, various kinds of information about prediction, such as prediction mode information, may be generated and transmitted to the entropy encoding unit 190. The information about prediction may be encoded in the entropy encoding unit 190 and output in a bitstream form. .

The intra predictor 185 may predict the current block by referring to the samples in the current picture. The referenced samples may be located in the neighborhood of the current block or may be located apart according to the prediction mode. In intra prediction, prediction modes may include a plurality of non-directional modes and a plurality of directional modes. Non-directional mode may include, for example, DC mode and planner mode (Planar mode). The directional mode may include, for example, 33 directional prediction modes or 65 directional prediction modes according to the degree of detail of the prediction direction. However, as an example, more or less directional prediction modes may be used depending on the setting. The intra predictor 185 predicts the neighboring block. Using the mode: It is also possible to determine the prediction mode applied to the current block.

The inter prediction unit 180 may derive the predicted block for the current block based on the reference block (reference sample array) specified by the motion vector on the reference picture. In this case, to reduce the amount of motion information transmitted in the inter prediction mode, the motion information may be predicted in units of blocks, sub-blocks, or samples based on the correlation of the motion information between the neighboring block and the current block. The motion information may include a motion vector and a reference picture index. The motion information may further include inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.) information. In the case of inter prediction, the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block present in the reference picture. The reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different. The temporal neighboring block may be called a co-located reference block, a co-located CU (colCU), etc., and a reference picture including the temporal neighboring block may be called a collocated picture (colPic). It may be. For example, the inter prediction unit 180 constructs a motion information candidate list based on neighboring blocks, and provides information indicating which candidates are used to derive a motion vector and / or a reference picture index of the current block. Can be generated. Inter prediction may be performed based on various examples. For example, in the case of the skip mode and the merge mode, the inter prediction unit 180 may use the motion information of the neighboring block as the motion information of the current block. In skip mode, residual signals are not transmitted unlike merge mode. 2019/194499 1 »（： 1 ^ 1 {2019/003805

17 may not. In the case of motion information prediction (MVP) mode, the motion vector of the current block is used by using the motion vector of the neighboring block as a motion vector predictor and signaling a motion vector difference. You can instruct.

The prediction signal generated through the inter predictor 180 or the intra predictor 18 may be used to generate a reconstruction signal or to generate a residual signal.

The transform unit 120 may generate transform coefficients by applying a transform technique to the residual signal. For example, _/, transformation techniques are DCT (Discrete Cosine Transform), DST (Discrete Sine Transform), KLT (Karhunen-Loeve Transform), GBT (Graph-Based Transform), 2. ^ · (Conditionally Non-linear Transform) CNT It may include at least one of the. Here, GBT means a conversion obtained from this graph when the relationship information between pixels is represented by a graph. CNT means a transform that is generated using and based on all previously reconstructed pixels, i.e., a signal. In addition, the conversion process may be applied to a pixel block having the same size as a square, or may be applied to a block having a variable size rather than a square.

The quantization unit 130 quantizes the transform coefficients and transmits the quantized transform coefficients to the entropy encoding unit 190. The entropy encoding unit 190 encodes the quantized signal (information about the quantized transform coefficients) and outputs the bitstream. have. The information about the quantized transform coefficients may be referred to as residual information. Quantizer 130 is a coefficient Based on a scan order, the quantized transform coefficients in the form of blocks may be rearranged into an i-dimensional vector form, and information about the quantized transform coefficients may be obtained based on the quantized transform coefficients in the form of the one-dimensional vector. You can also create The entropy encoding unit 190 may perform various encoding methods such as exponential Golomb, context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), and the like. The entropy encoding unit 190 may encode information necessary for video / image reconstruction other than quantized transform coefficients (eg, a value of syntax elements, etc.) together or separately. The encoded information (eg, encoded video / picture information) may be transmitted or stored in units of NALs (network abstraction layer) in the form of a bitstream. The bitstream may be transmitted through a network or stored in a digital storage medium. The network may include a broadcasting network and / or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, and the like. The signal output from the entropy encoding unit 190 may include a transmitting unit (not shown) for transmitting and / or a storing unit (not shown) for storing as an internal / external element of the encoding apparatus 100, or the transmitting unit The entropy encoding section 19 may be a component.

The quantized transform coefficients output from the quantization unit 130 may be used to generate a prediction signal. For example, the quantized transform coefficients may be reconstructed in the residual signal by applying inverse quantization and inverse transform through inverse quantization unit 140 and inverse transform unit 150 in a loop. The adder 155 intersects the restored residual signal. A reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array) can be generated by adding to the predictor 18 or the predicted signal output from the intra predictor 185. Processing as if the skip mode is applied If there is no residual for the target block, the predicted block may be used as the reconstructed block, and the adder 155 may be called a reconstructor or a reconstructed block generator The generated reconstruction signal may be the next processing target in the current picture. It may be used for intra prediction of a block, and may be used for inter prediction of a next picture through filtering as described below.

The filtering unit 160 may apply filtering to the reconstruction signal to improve subjective / objective picture quality. For example, the filtering unit 160 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and the modified reconstructed picture is stored in the memory 170, specifically, the DPB of the memory 170. Can be stored in The various filtering methods may include, for example, deblocking filtering, a sample adaptive offset, an adaptive loop filter, a bilateral filter, and the like. As described later in the description of each filtering method, the filtering unit 160 may generate various information about the filtering and transmit the generated information to the entropy encoding unit 190. The filtering information may be encoded in the entropy encoding unit 190 and output in the form of a bitstream.

The modified reconstructed picture transmitted to the memory 170 may be used as the reference picture in the inter predictor 180. When the inter prediction is applied through the encoding apparatus, the encoding apparatus may avoid prediction mismatch between the encoding apparatus 100 and the decoding apparatus. Efficiency can also be improved.

The memory 170 DPB may store the modified reconstructed picture for use as a reference picture in the inter predictor 180. The memory 17 may store motion information of a block from which the motion information in the current picture is derived (or encoded) and / or motion information of blocks in a picture that is already reconstructed. The stored motion information may be motion information of a spatial neighboring block. Alternatively, the memory 170 may store reconstructed samples of the reconstructed blocks in the current picture, and transmit the same to the inter predictor 180 to use the motion information of the temporal neighboring block. have.

2 is a schematic block diagram of a decoding apparatus in which an embodiment of the present invention is applied and decoding of a video / image signal is performed.

Referring to FIG. 2, the decoding apparatus 200 includes an entropy decoding unit 21, an inverse quantization unit 220, an inverse transform unit 230, an adder 23 23, a filter 240, a memory 250, and an interleaver. The prediction unit 260 and the intra prediction unit 265 may be configured to include the inter prediction unit 260 and the intra prediction unit 265, which may be called a prediction unit. 180) and an intra prediction unit 185. The inverse quantization unit 220 and the inverse transform unit 230 may be collectively referred to as a residual processing unit, that is, the residual processing unit 220, The inverse transform unit 230 may include the entropy decoding unit 210, the inverse quantization unit 220, the inverse transform unit 230, an adder 23, a filter 24, and an inter predictor 260. ) And the intra prediction unit 26 ¼ may be configured by one hardware component (for example, a decoder or a processor) according to an embodiment. Memory 170 is DPB (decoded picture buffer) and may be configured by a digital storage medium. When a bitstream including video / image information is input, the decoding apparatus 200 may reconstruct an image corresponding to a process in which video / image information is processed in the encoding apparatus of FIG. 1. For example, the decoding device 2 may perform decoding using a processing unit applied in the encoding device. Thus, the processing unit of decoding may be, for example, a coding unit, and the coding unit may be a coding tree unit or a maximum coding. The reconstructed video signal decoded and output through the decoding apparatus 200 may be reproduced through the reproducing apparatus.

The decoding apparatus 200 may receive a signal output from the encoding apparatus of FIG. 1 in the form of a bitstream, and the received signal may be decoded through the entropy decoding unit 21. For example, the entropy decoding unit 210 ) May parse the bitstream to derive information (eg, video / picture information) necessary for image reconstruction (or picture reconstruction), for example, the entropy decoding unit 210 may use exponential Golomb coding, CAVLC, or CABAC. The information in the bitstream may be decoded based on a coding method, and the quantized values of the syntax elements required for image reconstruction and the transform coefficients related to the residual may be output. Receives the bin corresponding to each syntax element, and decodes the syntax element information and the decoding information of the neighboring and decoding target blocks or the previous step. The context model is determined using the decoded symbol / bin information, and the probability of occurrence of the bin is determined according to the determined context model, i.e., the arithmetic decoding of the bin is performed to determine the value of each syntax element. A symbol corresponding to can be generated. In this case, the CABAC entropy decoding method may update the context model by using the information of the decoded symbol / bin for the context model of the next symbol / bean after determining the context model. The information related to the prediction among the information decoded by the entropy decoding unit 2110 is provided to the prediction unit (the inter prediction unit 260 and the intra prediction unit 26), and the entropy decoding unit 210 performs entropy decoding. Dual values, that is, quantized transform coefficients and related parameter information, may be input to the inverse quantization unit 220. Also, information about filtering among information decoded by the entropy decoding unit 210 may be transmitted to the filtering unit 240. Meanwhile, a receiver (not shown) for receiving a signal output from the encoding apparatus may be further configured as an internal / external element of the decoding apparatus 200, or the receiver may be configured of the entropy decoding unit 210. It may be an element.

The inverse quantization unit 220 may dequantize the quantized transform coefficients and output the transform coefficients. The inverse quantization unit 220 may rearrange the quantized transform coefficients in the form of a two-dimensional block. In this case, the reordering may be performed based on the coefficient scan order performed by the encoding apparatus. The inverse quantization unit 220 may perform inverse quantization on quantized transform coefficients using a quantization parameter (for example, quantization step size information), and may obtain transform coefficients.

The inverse transformer 230 inversely transforms the transform coefficients to obtain a residual signal (a residual block, a residual sample array).

The prediction unit may perform prediction on the current block and generate a predicted block including prediction samples for the current block. The prediction unit may determine whether intra prediction or inter prediction is applied to the current block based on the information about the prediction output from the entropy decoding unit 210, and may determine a specific intra / inter prediction mode. The intra predictor 265 may predict the current block by referring to the samples in the current picture. The referenced samples may be located in the neighborhood of the current block or may be located apart according to the prediction mode. In intra prediction, prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The intra predictor 265 may determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring block.

The inter prediction unit 26 may derive a predicted block for the current block based on a reference block (reference sample array) specified by a motion vector on the reference picture, wherein the motion information transmitted in the inter prediction mode may be derived. In order to reduce the amount, the motion information may be predicted in units of blocks, subblocks, or samples based on the correlation of the motion information between the neighboring block and the current block, and the motion information may include a motion vector and a reference picture index. The information may further include information on inter prediction directions (L0 prediction, L1 prediction, Bi prediction, etc.) In the case of inter prediction, neighboring blocks are added to spatial neighboring blocks and reference pictures existing in the current picture. It may include a temporal neighboring block that exists, for example, inter, i.e., 260 may include neighboring blocks. Configure the motion information candidate list is based on, and wherein, based on the received candidate selection information can be derived for the current block in the motion vector and / or the reference picture indexes can be an inter-prediction performed based on different prediction modes, The information about the prediction may include information indicating a mode of inter prediction for the current block.

The adder 235 adds the obtained residual signal to the predictive signal (predicted block, predictive sample array) output from the inter predictor 26 or the intra predictor 265 to restore the reconstructed signal (restored picture, reconstructed block). If there is no residual for the block to be processed, such as when the skip mode is applied, the predicted block may be used as the reconstructed block.

The adder 235 may be called a restoration unit or a restoration block generation unit. The generated reconstruction signal may be used for intra prediction of a next processing target block in a current picture, and may be used for inter prediction of a next picture through filtering as described below.

The filtering unit 240 may improve subjective / objective picture quality by applying filtering to the reconstruction signal. For example, the filtering unit 240 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and the modified reconstructed picture is stored in the memory 250, specifically, the DPB of the memory 250. Can be sent to. The various filtering methods may include, for example, deblocking filtering, a sample adaptive offset, an adaptive loop filter, a bilateral filter, and the like.

The (modified) reconstructed picture stored in the DPB of the memory 250 may be used as the reference picture in the inter predictor 260. The memory 250 may store the motion information of the block from which the motion information in the current picture is derived (or decoded) and / or the motion information of the blocks in the picture that have already been reconstructed. The stored motion information is The inter prediction unit 260 may transmit the motion information of the spatial neighboring block or the motion information of the temporal neighboring block to the inter predictor 260. The memory 170 may store reconstructed samples of reconstructed blocks in the current picture, and may transfer the intra prediction unit 265.

In the present specification, the embodiments described by the filtering unit 160-the inter prediction unit 180 and the intra prediction unit 185 of the encoding apparatus 100 are respectively the filtering unit 240 and the inter prediction of the decoding apparatus 200. The same may also apply to the unit 260 and the intra predictor 265. Block Partitioning

The video / image coding method according to this document may be performed based on various detailed techniques, and each detailed technique will be described as follows. Techniques described below include prediction, residual processing ((inverse) transformation, (inverse) quantization, etc.), syntax element coding, filtering, partitioning / division, etc., in the video / image encoding / decoding procedures described above and / or below. It will be apparent to those skilled in the art that they may be involved in related procedures. The block partitioning procedure according to this document may be performed by the image splitter 110 of the encoding apparatus described above, and the partitioning related information may be processed (encoded) by the entropy encoding unit 190 and transmitted to the decoding apparatus in the form of a bitstream. . The entropy decoding unit 210 of the decoding apparatus derives a block partitioning structure of a current picture based on the partitioning related information obtained from the bitstream, and based on this, a series of procedures (eg, prediction and residual) for image decoding. Processing, block restoration, in-loop filtering, etc.). 2019/194499 1 »（： 1/10 公 019/003805

26

Partitioning of picture into CTUs

Pictures can be divided into a sequence of coding tree units (CTUs). A CTU may correspond to a coding tree block (US) or a CTU may include a coding tree block of luma samples and two coding tree blocks of corresponding chroma samples. In other words, a picture containing three sample arrays may be used. For CTU, the CTU may include NxN blocks of luma samples and two corresponding blocks of chroma samples.

The maximum allowable size of for coding, prediction, etc. may be different from the maximum allowable size of CTU for transform. For example, the maximum allowable size of the luma block in the CTU may be 128x128.

Partitioniq of the CTUs using a tree structure

The CTU may be divided into bands based on a quad-tree (QT) structure. The quadtree structure may be called a quaternary tree structure. This is to reflect various local characteristics. Meanwhile, in this document, the CTU may be divided based on a multitype tree structure partition including a binary tree (BT) and a ternary tree (TT) as well as a quad tree. Hereinafter, the QTBT structure may include a quadtree and binary tree based partition structure, and the QTBTTT may include a quadtree, binary tree, and ternary tree based partition structure. Alternatively, the QTBT structure may include a quadtree, binary tree and ternary tree based partitioning structure. In a coding tree structure, a CU may have a square or rectangular shape. The CTU may first be divided into quadtree structures. Quad leaf tree leaf Nodes can be further partitioned by a multitype tree structure. 3 is a diagram illustrating an example of a multi-type tree structure as an embodiment to which the present invention can be applied.

In one embodiment of the present invention, the multitype tree structure may include four partition types as shown in FIG. The four split types include vertical binary splitting (SPLIT_BT_VER), horizontal binary splitting (SPLIT_BT_HOR), vertical ternary splitting (SPLIT_TT_VER), and horizontal ternary splitting (SPLIT_TT_HOR). ) May be included. Leaf nodes of the multitype tree structure may be called CUs. These CUs can be used for prediction and transform procedures. In general, CU, PU, in the present document may have the same block size. However, when the maximum supported transform length is smaller than the width or height of the CU-³1 color component, the CU and the TU may have different block sizes.

FIG. 4 is a diagram illustrating a signaling mechanism of partition partition information of a quadtree with nested multi-type tree structure according to an embodiment to which the present invention may be applied.

Here, the CTU is treated as the root of the quadtree and partitioned for the first time into a quadtree structure. Each quadtree leaf node may then be further partitioned into a multitype tree structure. In a multitype tree structure, a first flag (ex. Mtt_split_cu_flag) indicates whether the node is additionally partitioned. 2019/194499 1 »（： 1/10 公 019/003805

28 is signaled for. If the corresponding node is additionally partitioned, a second flag (ex. Mtt_split_cu__verticla_flag) may be signaled to indicate the splitting direction. Thereafter, a third flag (ex. Mtt_split_cu__binary_flag) may be signaled to indicate whether the partition type is binary partition or ternary partition. For example, based on the mtt__split_cu_vertical__flag and the mtt_split_cu_binary_flag, a multitype tree splitting mode (MttSpl_tMode) of a CU 7].

Can be derived as S.1.

Table 1

FIG. 5 is a diagram illustrating a method of dividing () into multiple CUs based on a quadtree and a accompanying multi-type tree structure according to an embodiment to which the present invention may be applied.

Here, bold block edges represent quadtree partitioning, and the remaining edges represent multitype tree partitioning. A quadtree partition with a multitype tree may provide a content-adapted coding tree structure. Is 2019/194499 1 »（： 1/10 公 019/003805

29 coded block can be ^matched, Mie. Or 0 may include a coding block of luma samples and two coding blocks of corresponding chroma samples. The size of 0 ：

Or 4 × 4 in luma sample units. For example, in 4: 2: 0 color format ((chroma format), the maximum chroma 03 size is

The size may be 2 × 2.

For example, the maximum allowable in this article

Size is 64x64, maximum allowed

The size may be 32x32. If the width or height divided according to the tree structure is larger than the maximum conversion width or height, the corresponding horizontal and vertical directions are automatically

May be partitioned until the size limit is satisfied.

Meanwhile, for a quadtree coding tree scheme involving a multitype tree, the following parameters may be defined and identified as a smoke syntax element.

-CTU size: the root node size of a quaternary tree

MinQTSize: the minimum allowed quaternary tree leaf node size

MaxBtSize: the maximum allowed binary tree root node size ᅳ MaxTtSze: the maximum allowed ternary tree root node size

-MaxMttDepth: the max 丄 mum allowed hierarchy depth of multi-type tree splitting from a quadtree leaf

MinBtSzeze the minimum allowed binary tree leaf node size

MinTtSize: the minimum allowed ternary tree leaf node size

As an example of a quadtree coding tree structure involving a multitype tree, the CTU size may be set to 64x64 blocks of 128x128 luma samples and two corresponding chroma samples (in 4: 2: 0 chroma format). In this case, MinOTSize is set to 16x16, MaxBtSize is set to 128x128, and MaxTtSzie is

It can be set to 64x64, MinBtSize and MinTtSize (for both width and height) to 4x4, and MaxMttDepth to 4. Quarttree partitioning may be applied to the CTU to generate quadtree leaf nodes. The quadtree leaf node may be called a leaf QT node. Quadtree leaf nodes may have a size of 16x16 (ie the MinOTSize) from 128x128 (i.e. the CTU size). If the leaf QT node is 128x128, it may not be additionally divided into a binary tree / a ternary tree. This is because in this case even if split, it exceeds MaxBtsize and MaxTtszie (ie 64x64). In other cases, the leaf QT node may be further divided into a multi-tap tree. Therefore, the leaf QT node is the root node for the multitype tree, and the leaf QT node may have a multitype tree depth (mttDepth) 0 value. If the multitype tree depth reaches MaxMttdepth (ex. 4), the stock price split may no longer be considered. If the width of the multitype tree node is equal to MinBtSize and less than or equal to 2xMinTtSize, then no further horizontal split may be considered. If the height of the multitype tree node is equal to MinBtSize and less than or equal to 2xMinTtSize, no further vertical split may be considered. FIG. 6 is a diagram illustrating a method of limiting ternary-tree partitioning as an embodiment to which the present invention may be applied.

With reference to FIG. 6, to allow for 64x64 luma blocks and 32x32 chroma pipeline designs in a hardware decoder, TT partitioning may be limited in certain cases. For example, when the width or height of the luma coding block is greater than a predetermined specific value (eg, 32, 64), TT partitioning may be limited as shown in FIG. 6.

In this document, the coding tree scheme may support that the luma and chroma blocks have separate block tree structures. For P and B slices, luma and chroma (in one CTU may be limited to have the same coding tree structure. However, for I slices, luma and chroma blocks may have separate block tree structures from each other. If an individual block tree mode is applied, the luma CTB can be split into chunks based on a particular coding tree structure, and the chroma CTB can be split into chroma CUs based on another coding tree structure. My CU may be composed of a coding block of a luma component or coding blocks of two chroma components, and a CU of a P or B slice may be composed of blocks of three color components.

In the above-described "Partitonig of the CTUs using a tree structure", a quadtree coding tree structure involving a multitype tree has been described, but a structure in which a CU is divided is not limited thereto. For example, the BT structure and the TT structure may be interpreted as a concept included in a multiple partitioning tree (MPT) structure, and the CU may be interpreted to be divided through the QT structure and the MPT structure. In one example where a subtree is split through a QT structure and an MPT structure, a syntax element (eg, MPT_split_type) that contains information about how many blocks the leaf node of the QT structure is divided into, and the leaf node of the QT structure The partition structure may be determined by signaling a syntax element (eg, MPT_split_mode) that includes information about which direction of the horizontal direction to split.

In another example, the CU may be partitioned in a different way than the QT structure, BT structure or TT structure. That is, according to the QT structure, the CUs of the child maps are divided into one-fourth the size of the CUs of the parent map, or the CUs of the child maps are divided into one-half size of (of the parent maps) according to the BT structure, or according to the TT structure. In contrast to subdivided into 1/4 or 1/2 sizes of CU7> upper depth of the lower map, the CU of the lower depth is sometimes 1/5, 1/3, 3/8, 3 of the upper map's ⑶. It can be divided into / 5, 2/3 or 5/8 size, the way in which the CU is divided is not limited thereto.

If a portion of a tree node block exceeds the bottom or right picture boundary, the tree node block restricts all coded its samples to be placed within the picture boundaries. Can be. In this case, for example, the following division rule may be applied.

-If a portion of a tree node block exceeds both the bottom and the right picture boundaries,

-If the block is a QT node and the size of the block is larger than the minimum QT size, the block is forced to be split with QT split mode.

-Otherwise, the block is forced to be split with SPLIT_BT_HOR mode

-Otherwise if a portion of a tree node block exceeds the bottom picture boundaries,

-If the block is a QT node, and the size of the block is larger than the minimum QT size, and the size of the block is larger than the maximum BT size, the block is forced to be split with QT split mode.

-Otherwise, if the block is a QT node, and the size of the block is larger than the minimum QT size and the size of the block is smaller than or equal to the maximum BT size, the block is forced to be split with QT split mode or SPLIT_BT_HOR mode.

-Otherwise (the block is a BTT node or the size of the block is smaller than or equal to the minimum QT size), the block is forced to be split with SPLIT_BT_HOR mode.

-Otherwise if a portion of a tree node block exceeds the right picture boundaries,

-Otherwise, if the block is a QT node, and the size of the 2019/194499 1 »（： 1/10 公 019/003805

34 block is larger than the minimum QT size and the size of the block is smaller than or equal to the maximum BT size, the block is forced to be split with QT split mode or SPLIT_BT_VER mode,

-Otherwise (the block is a BTT node or the size of the block is smaller than or equal to the minimum QT size), the block is forced to be split with SPLIT_JBT_VER mode.

On the other hand, the quadtree coded block structure with the multi-type tree described above can provide a very flexible block partitioning structure. Because of the partition types supported in a multitype tree, different partition patterns can sometimes lead to potentially identical coding block structure results. By limiting the occurrence of such redundant partition patterns, the data amount of partitioning information can be reduced. It demonstrates with reference to the following drawings.

FIG. 7 is a diagram illustrating redundant division patterns that may occur in binary tree division and ternary tree division, as an embodiment to which the present invention may be applied.

As shown in Fig. 7, continuous in one direction of two levels

W] inary §: ¾ (two levels of consecutive binary splits in one direction) has the same coding block structure as the binary split for the center partition after the ternary split. In this case, the binary tree split in the given direction for the center partition of the ternary tree split may be limited. This restriction can be applied to the sons of all pictures. This particular split If limited, the signaling of corresponding syntax elements may be modified to reflect this limited case, thereby reducing the number of bits signaled for partitioning. For example, as shown in FIG. 7, when the binary tree split for the center partition of the CU is restricted, the mtt_split_cu_binary_flag syntax element indicating whether the split is a binary split or a tenary split is not signaled, and its value is Can be inferred by the decoder to zero. Prediction

The decoded portion of the current picture or other pictures in which the current processing unit is included may be used to reconstruct the current processing unit in which decoding is performed.

An intra picture or I picture (slice) that uses only the current picture for reconstruction, that is, performs only intra-picture prediction, and a picture (slice) that uses a maximum of one motion vector and a reference index to predict each unit. A picture (slice) using a picture (predictive picture) or a P picture (slice), up to two motion vectors, and a reference index can be referred to as a bi-predictive picture or a B picture (slice).

Intra prediction means a prediction method that derives the current processing block from data elements (eg, sample values, etc.) of the same decoded picture (or slice). That is, a method of predicting pixel values of the current processing block by referring to reconstructed regions in the current picture.

Hereinafter, the inter prediction will be described in more detail. Inter-example (111 七 6 1 ^ 6 mountains: 1。1 ：: 10) 1) (or inter-screen example)

Inter prediction means a prediction method of deriving a current processing block based on data elements (eg, sample values or motion vectors, etc.) of pictures other than the current picture. That is, a method of predicting pixel values of the current processing block by referring to reconstructed regions in other reconstructed pictures other than the current picture.

Inter prediction (or inter picture prediction) is a technique for removing redundancy existing between pictures. Mostly, motion estimation and motion compensation are performed.

The present invention describes a detailed description of the inter prediction method described above with reference to FIGS. 1 and 2. The decoder may be represented by the inter prediction-based video / video decoding method of FIG. 1 ◦ described later and the inter prediction unit in the decoding apparatus of FIG. 11. have. In addition, the encoder may be represented by the inter prediction based video / video encoding method of FIG. 8 and the inter prediction unit in the encoding apparatus of FIG. 9. In addition, the data encoded by FIGS. 8 and 9 may be stored in the form of a bitstream.

The prediction unit of the encoding apparatus / decoding apparatus may derive the prediction sample by performing inter prediction on a block basis. Inter-prediction may represent an example that is derived in a manner dependent on data elements (eg sample values, motion information, etc.) of the picture (s) other than the current picture. If an inter-example is applied to the current block, the predicted block (prediction sample array) for the current block is derived based on the reference block (reference sample array) specified by the motion vector on the reference picture indicated by the reference picture index. Can be. In this case, in order to reduce the amount of motion information transmitted in the inter prediction mode, the motion information of the current block may be predicted in units of blocks, subblocks, or samples based on the correlation of the motion information between the neighboring block and the current block. The motion information may include a motion vector and a reference picture index. The motion information may further include? Information such as inter prediction type (L0 prediction, L1 prediction, Bi prediction).

When inter prediction is applied, the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block present in the reference picture. The reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different. The temporal neighboring block may be called a colocated reference block, a co-located CU (colCU), or the like, and a reference picture including the temporal neighboring block may be called a collocated picture (eg, a collocated picture). For example, a motion information candidate list may be constructed based on neighboring blocks of the current block, and indicates which candidates are selected (used) to derive the motion vector and / or reference picture index of the current block. Flag or index information may be signaled.

Inter prediction may be performed based on various prediction modes. For example, in the case of the skip mode and the merge mode, the motion information of the current block may be the same as the motion information of the selected neighboring block. In the skip mode, unlike the merge mode, the residual signal may not be transmitted. In the case of motion information prediction (MVP) mode, the motion vector of the selected neighboring block is moved. Using as a motion vector predictor, the motion vector difference can be signaled. In this case, the motion vector of the current block may be derived using the sum of the motion vector predictor and the motion vector difference.

8 and 9 illustrate an inter prediction based video / image encoding method and an inter prediction unit in an encoding apparatus according to an embodiment of the present invention.

8 and 9, S801 may be performed by the inter prediction unit 180 of the encoding apparatus, and S802 may be performed by the residual processing unit of the encoding apparatus. In detail, S802 may be performed by the subtracting unit 115 of the encoding apparatus. In S803, prediction information may be derived by the inter prediction unit 180 and encoded by the entropy encoding unit 190. In S803, the residual information may be derived by the residual processing unit and encoded by the entropy encoding unit 190. The residual information is information about the residual samples. The residual information may include information about quantized transform coefficients for the residual samples.

As described above, the residual samples may be derived as transform coefficients through the transform unit 120 of the encoding apparatus, and the transform coefficients may be derived as transform coefficients quantized through the quantization unit 13. Information about the transform coefficients may be encoded in the entropy encoding unit 190 through the residual coding procedure.

The encoding apparatus performs inter prediction on the current block (S801). Encoding The apparatus may derive inter prediction mode and motion information of the current block and generate prediction samples of the current block. In this case, the inter prediction mode determination, the motion information derivation, and the prediction samples generation procedure may be performed simultaneously, or one procedure may be performed before the other. For example, the inter prediction unit 18 of the encoder device may include a prediction mode determination unit 181, a motion information derivation unit 182, and a prediction sample derivation unit 183, and the prediction mode determination unit 181. In FIG. 2, a prediction mode for the current block is determined, motion information derivation unit 182 derives motion information of the current block, and prediction sample derivation unit 183 may derive motion samples of the current block.

For example, the inter prediction unit 180 of the encoding apparatus searches for a block similar to the current block in a predetermined area (search area) of reference pictures through motion estimation, and a difference from the current block is determined. Reference blocks that are minimum or below a certain criterion may be derived. Based on this, a reference picture index indicating a reference picture in which the reference block is located may be derived, and a motion vector may be derived based on a position difference between the reference block and the current block. The encoding apparatus may determine a mode applied to the current block among various prediction modes. The encoding apparatus may compare RD costs for the various prediction modes and determine an optimal prediction mode for the current block.

For example, when a skip mode or a merge mode is applied to the current block, the encoding apparatus constructs a merge candidate list to be described later, and among the reference blocks indicated by merge candidates included in the merge candidate list. It is possible to derive a reference block whose difference from the current block is a minimum or a predetermined criterion. have. In this case, a merge candidate associated with the derived reference block is selected, and merge index information indicating the selected merge candidate may be generated and signaled to the decoding apparatus. The motion information of the current block may be derived using the motion information of the selected merge candidate.

As another example, when the (A) MVP mode is applied to the current block, the encoding apparatus constructs a (A) MVP candidate list to be described later, and among the mvp (motion vector predictor) candidates included in the (A) MVP candidate list. The motion vector of the selected mvp candidate may be used as mvp of the current block. In this case, for example, a motion vector indicating a reference block derived by the above-described motion estimation may be used as the motion vector of the current block, and the difference with the motion vector of the current block is smallest among the mvp candidates. An mvp candidate with a motion vector may be the selected mvp candidate. A motion vector difference (MVD), which is a difference obtained by subtracting the mvp from the motion vector of the current block, may be plotted. In this case, the information about the MVD may be signaled to the decoding apparatus. In addition, when the (A) MVP mode is applied, the value of the reference picture index may be configured with reference picture index information and separately signaled to the decoding apparatus.

The encoding apparatus may derive residual samples based on the prediction samples (S802). The encoding apparatus may derive the residual samples by comparing the original samples of the current block with the prediction samples.

The encoding apparatus encodes image information including prediction information and residual information (S803). The encoding apparatus may output the encoded image information in the form of a bitstream. The prediction information is information related to the prediction procedure. Information (eg, skip flag, merge flag or mode index, etc.) and motion information. The information about the motion information is candidate selection information (ex. merge index, mvp flag or mvp index). In addition, the information on the motion information may include the information on the above-described MVD and / or reference picture index information.

The information about the motion information may include information indicating whether L0 prediction, L1 prediction, or bi prediction is applied. The residual information is information about the residual samples. The residual information may include information about quantized transform coefficients for the residual samples. The output bitstream may be stored in a (digital) storage medium and delivered to the decoding device, or may be delivered to the decoding device via a network.

Meanwhile, as described above, the encoding apparatus may generate a reconstructed picture (including the reconstructed samples and the reconstructed block) based on the reference samples and the residual samples. This is because the encoding apparatus derives the same prediction result as that performed in the decoding apparatus, and thus the coding efficiency can be increased. Accordingly, the encoding apparatus may store a reconstructed picture (or reconstructed samples, reconstructed block) in a memory and use the reference picture for inter prediction. As described above, an in-loop filtering procedure may be further applied to the reconstructed picture.

10 and 11, a decoding apparatus is performed in the encoding apparatus. 2019/194499 1 »（： 1 ^ 1 {2019/003805

An operation corresponding to operation 42 may be performed. The decoding apparatus may perform prediction on the current block and derive prediction samples based on the received prediction information.

31001 to 31003 may be performed by the inter prediction unit 260 of the decoding apparatus, and residual information of 004 may be obtained from the bitstream by the entropy decoding unit 210 of the decoding apparatus. The residual processor of the decoding apparatus may derive residual samples for the current block based on the residual information. In detail, the inverse quantization unit of the residual processing unit 22 performs dequantization based on the quantized transform coefficients derived based on the residual information to derive transform coefficients, and the inverse transform unit 230 of the residual processing unit. ) May derive residual samples for the current block by performing an inverse transform on the transform coefficients 005 may be performed by an adder 235 or a reconstruction unit of a decoding apparatus.

In detail, the decoding apparatus may determine a prediction mode for the current block based on the received prediction information (001). The decoding apparatus may determine which inter prediction mode is applied to the current block based on prediction mode information in the prediction information.

Can be. The inter prediction mode candidates may include a skip mode, a merge mode, and / or a (¥) mode, or may include various inter prediction modes described below. The decoding apparatus derives the motion information of the current block based on the determined inter prediction mode (S1002). For example, when a skip mode or a merge mode is applied to the current block, the decoding apparatus may configure a merge candidate list to be described later, and select one merge candidate among merge candidates included in the merge candidate list. The selection may be performed based on the above merge information. The motion information of the current block may be derived using the motion information of the selected merge candidate. The motion information of the selected merge candidate may be used as motion information of the current block.

As another example, when the (A) MVP mode is applied to the current block, the decoding apparatus constructs the (A) MVP candidate list to be described later, and (A) among the mvp (motion vector predictor) candidates included in the MVP candidate list. The motion vector of the selected mvp candidate may be used as mvp of the current block. The selection may be performed based on the above-described selection information (mvp flag or mvp index). In this case, the MVD of the current block may be derived based on the information on the MVD, and the motion vector of the current block may be derived based on mvp and the MVD of the current block. In addition, the reference picture index of the current block may be derived based on the reference picture index information. The picture indicated by the reference picture index in the reference picture list for the current block may be derived as a reference picture referred for inter prediction of the current block.

Meanwhile, as described below, motion information of the current block may be derived without constructing a candidate list, and in this case, motion information of the current block may be derived according to a procedure disclosed in a prediction mode described later. In this case, 2019/194499 1 »（： 1 ^ 1 {2019/003805

44 Candidate list construction can be omitted.

The decoding apparatus may generate prediction samples for the current block based on the motion information of the current block (31003). In this case, the reference picture may be derived based on the reference picture index of the current block, and the prediction samples of the current block may be derived using the samples of the reference block indicated by the motion vector of the current block on the reference picture. In this case, as described below, a prediction sample filtering procedure for all or some of the prediction samples of the current block may be further performed.

For example, the inter prediction unit 260 of the decoding apparatus may include a prediction mode determination unit 261, a motion information derivation unit 262, and a prediction sample derivation unit 263, and the prediction mode determination unit 261 may be used. Determining a prediction mode for the current block based on the prediction mode information received in the step, and based on the information on the motion information received from the motion information derivation unit 262, motion information (motion vector and / or A reference picture index, etc.), and the predictive sample derivation unit 263 may derive the predictive samples of the current block.

The decoding apparatus generates residual samples for the current block based on the received residual information (31004). The decoding apparatus may generate reconstructed samples for the current block based on the prediction samples and the residual samples, and generate a reconstructed picture based thereon (31005). After that, the in-loop filtering procedure may be further applied to the reconstructed picture as described above.

As described above, the inter prediction procedure includes an inter prediction mode determining step, a motion information deriving step according to the determined prediction mode, and a prediction based on the derived motion information. It may include performing (predicting sample generation) step. Determination of inter prediction mode Various inter prediction modes may be used for prediction of a current block in a picture. For example, various modes such as merge mode, skip mode, MVP mode, and affine mode may be used. Decoder side motion vector refinement (DMVR) mode, adaptive motion vector resolution (AMVR) mode, and the like may be further used as a secondary mode. The affine mode may be called an affine motion prediction mode. MVP mode may be referred to as advanced motion vector prediction (AMVP) mode. Prediction mode information indicating the inter prediction mode of the current block may be signaled from the encoding device to the decoding device. The prediction mode information may be included in the bitstream and received by the decoding apparatus. The prediction mode information may include index information indicating one of a plurality of candidate modes. Alternatively, the inter prediction mode may be indicated through hierarchical signaling of flag information. In this case, the prediction mode information may include one or more flags.

For example, a skip flag is signaled to indicate whether a skip mode is applied, and if a skip mode is not applied, a merge flag is signaled to indicate whether a merge mode is applied, and if a merge mode is not applied, an MVP mode is applied. Or further signal a flag for further classification. The affine mode may be signaled in an independent mode, or may be signaled in a mode dependent on a merge mode or an MVP mode. For example, the affine mode As described later, one candidate of the merge candidate list or the MVP candidate list may be configured.

Derivation of motion information according to inter prediction mode

Inter prediction may be performed using motion information of the current block. The encoding apparatus may derive optimal motion information for the current block through a motion estimation procedure. For example, the encoding apparatus may search for a highly correlated similar reference block in units of fractional pixels within a predetermined search range in the reference picture by using the original block in the original picture for the current block, thereby deriving motion information. can do. Similarity of blocks can be derived based on the difference of phase based sample values. For example, the similarity of a block may be calculated based on the SAD ^: between the current block (or template of the current block) and the reference block (or template of the reference block). In this case, motion information may be derived based on a reference block having the smallest SAD in the search area. The derived motion information may be signaled to the decoding apparatus according to various methods based on the inter prediction mode. Merge mode and skip mode

:

When the merge mode is applied, the motion information of the current prediction block is not directly transmitted, but using the motion information of the neighboring prediction block. The motion information of the current prediction block is derived. Accordingly, the motion information of the current prediction block can be indicated by transmitting flag information indicating that the merge mode is used and a merge index indicating which neighboring prediction blocks have been used.

The encoder can search the merge candidate block used to derive motion information of the current prediction block to perform the merge mode. For example, up to five merge candidate blocks may be used, but the present invention is not limited thereto. The maximum number of merge candidate blocks may be transmitted in a slice header (or tile group header), but the present invention is not limited thereto. After finding the merge candidate blocks, the encoder may generate a merge candidate list, and select the merge candidate block having the smallest cost among them as the final merge candidate block.

The present invention provides various embodiments of a merge candidate block forming the merge candidate list.

The merge candidate list may use, for example, five merge candidate blocks. For example, four spatial merge candidates

One temporal merge candidate can be used. As a specific example, in the case of the spatial merge candidate, the blocks shown in FIG. 12 may be used as the spatial merge candidate.

Referring to FIG. 13, the coding device (encoder / decoder) is a spatial neighbor of the current block. The spatial merge candidates derived by searching for blocks are inserted into the merge candidate list (S1301). For example, the spatially close to the current block are the lower left corner of the block or a neighboring block, the left neighboring _block. The upper right corner corner block, the upper upper corner block, the upper left corner corner blocks may be included. However, as an example, in addition to the above-described spatial peripheral blocks, additional peripheral blocks such as a right peripheral block, a lower peripheral block, and a lower right peripheral block may be further used as the spatial peripheral blocks. The coding apparatus may search for the spatial neighboring blocks based on priority, detect available blocks, and derive motion information of the detected blocks as the spatial merge candidates. For example, the encoder and decoder can be indexed to sequentially composed of the remaining candidate lists the ^five blocks of Al, Bl, BO, the candidates by searching in the order of the AO, B2, available shown in Fig.

The coding apparatus inserts the temporal merge candidate derived by searching the temporal neighboring block of the current block into the merge candidate list (S1302). The temporal neighboring block may be located on a reference picture that is a picture different from the current picture in which the current block is located. The reference picture in which the temporal neighboring block is located may be called a collocated picture or a col picture. The temporal neighboring block may be searched in the order of the lower right corner peripheral block and the lower right center block of the co-located block with respect to the current block on the col picture.

On the other hand, when motion data compression is applied, specific motion information may be stored as representative motion information for each predetermined storage unit in the col picture. In this case, it is not necessary to store the motion information for all the blocks in the predetermined storage unit, thereby obtaining a motion data compression effect. this In this case, the constant storage unit may be predetermined, for example, 16x16 sample units, 8x8 sample units, or the like, or size information about the constant storage unit may be signaled from the encoder to the decoder. When the motion data compression is applied, the motion information of the temporal neighboring block may be replaced with the constant storage unit and the representative motion information in which the temporal neighboring block is located.

That is, in this case, in terms of implementation, the arithmetic left shifted position after arithmetic right shifted by a predetermined value based on the coordinates (upper left sample position) of the temporal neighboring block, not the prediction block located at the coordinates of the temporal neighboring block. The temporal merge candidate may be derived based on the motion information of the covering prediction block. For example, when the constant storage unit is 2nx2n sample units, and the coordinates of the temporal neighboring block are (xTnb, yTnb), the modified positions ((xTnb >> n) << n), (yTnb> ñn (e.g., motion information of a block located at < n >) may be used for the temporal merge candidate.

Specifically, for example, when the constant storage unit is a 16x16 sample unit, if the coordinate of the temporal neighboring block is (xTnb, yTnb), it is a modified position.

The motion information of the prediction block located at ((xTnb »4)« 4), (yTnb ñ> 4) << 4)) may be used for the temporal merge candidate. Or, for example, when the constant storage unit is 8x8 sample units, when the coordinates of the temporal neighboring block are (xTnb, yTnb), the modified position ((xTnb >> 3) << 3), (yTnb ñ Motion information of the prediction block located at < 3 >)<<3) can be used for the temporal merge candidate. The coding apparatus may check whether the number of current merge candidates is smaller than the number of maximum merge candidates (S1303). The maximum number of merge candidates may be predefined or signaled at the encoder to the decoder. For example, the encoder may generate information about the maximum number of merge candidates, encode the information, and transmit the encoded information to the decoder in the form of a bitstream. If the maximum number of merge candidates is filled, the subsequent candidate addition process may not proceed.

If the number of the current merge candidates is smaller than the maximum merge candidates as a result of the checking, the coding apparatus inserts an additional merge candidate into the merge candidate list (S1304). The additional merge candidate may include, for example, ATMVP, combined bi-predictive merge candidate (when the slice type of the current slice is B type) and / or zero vector merge candidate.

As a result of the checking, when the number of the current merge candidates is not smaller than the number of the maximum merge candidates, the coding apparatus may terminate the construction of the merge candidate list. In this case, the encoder may select an optimal merge candidate among merge candidates constituting the merge candidate list based on a rate-distortion (RD) cost, and signal selection information (ex. Merge index) indicating the selected merge candidate to the decoder. can do. The decoder may select the optimal merge candidate based on the merge candidate list and the selection information.

As described above, the motion information of the selected merge candidate may be used as the motion information of the current block, and the prediction samples of the current block may be derived based on the motion information of the current block. An encoder can derive residual samples of the current block based on the prediction samples, 2019/194499 1 »（： 1/10 公 019/003805

Residual information about the 51 residual samples may be signaled to the decoder. The decoder may generate reconstructed samples based on the residual samples derived from the residual information and the prediction samples, and generate a reconstructed picture based on the same.

When the skip mode is applied, the motion information of the current block can be derived in the same manner as when the merge mode is applied. However, when the skip mode is applied, the residual_signal for the corresponding block is omitted, and thus the prediction samples may be used as reconstructed samples. MVP mode

When the Motion Vector Prediction (MVP) mode is applied, the motion vector and / or the temporal neighboring block (or col block) of the reconstructed spatial neighboring block (which may be, for example, the neighboring block described above with reference to FIG. 12). Using the motion vector, a motion vector predictor (mvp) candidate list may be generated. That is, the motion vector of the reconstructed spatial neighboring block and / or the motion vector corresponding to the temporal neighboring block may be used as a motion vector predictor candidate.

The information about the prediction may include selection information (ex. MVP flag or MVP index) indicating an optimal motion vector predictor candidate selected from the motion vector predictor candidates included in the list. In this case, the prediction unit may determine the selection information. 2019/194499 1 »（： 1/10 公 019/003805

52, a motion vector predictor of the current block may be selected from among motion vector predictor candidates included in the motion vector candidate list. The prediction unit of the encoding apparatus may obtain a motion vector difference between the motion vector and the motion vector predictor of the current block, and may encode the same and output the result in a bitstream form.

It may be obtained by subtracting the motion vector predictor from the motion vector of the current block. In this case, the prediction unit of the decoding apparatus may obtain a motion vector difference included in the information about the prediction, and derive the motion vector of the current block by adding the motion vector difference and the motion vector predictor. The prediction unit of the decoding apparatus may obtain or derive a reference picture index or the like indicating the reference picture from the information about the prediction. For example, the motion vector predictor candidate list may be configured as shown in FIG. 14.

ATMVP (Advanced Temporal Motion Vector Prediction)

15 and 16 are diagrams for describing a method of deriving an Advanced Temporal Motion Vector Prediction (ATMVP) candidate as an embodiment to which the present invention is applied.

Referring to FIG. 15, an ATMVP is a method of deriving motion information for subblocks of a coding unit based on motion information of collocated blocks of a neighboring picture in time. This can improve the performance of Temporal Motion Vector Prediction (TMVP) and reduce the complexity of common or worst case. In the present invention, ATMVP is a subblock-based temporal merging candidate, It may also be referred to as SbTMVP.

In one embodiment of the present invention, ATMVP may be derived by the following process.

First, the encoder / decoder may add motion vectors from spatial neighboring coding units if a neighboring coding unit is available and the motion vector of the available coding unit is different from the motion vector in the current candidate list. For example, referring to FIG. 16, the above-described process may be performed in the order of Al, Bl, BO, AO, and B2. As another example, in order to improve the complexity, the above-described process may derive ATMVP using only the motion vector of the fixed position (eg, A1 position) block.

The encoder / decoder may be used to determine a position from which the first motion vector candidate among the available No spatial candidates is derived from the collocated picture and each sub-block. Where No represents the number of space candidates available. If No is 0, a collocated picture and a collocated position of motion 0 may be used to derive motion information of each subblock.

When multiple reference pictures are used, collocated pictures of different coding units may not be the same in ATMVP. For different coding units in the current picture, having different collocated pictures for ATMVP derivation means that motion information fields of multiple reference pictures must be derived, which is undesirable because it increases memory bandwidth. not. Thus, the present invention provides a more simplified design that uses the same collocated picture when inducing ATMVP. For example, a method of using the same collocated picture may be defined in a slice (or tile group) header, but the present invention is not limited thereto. For example, at the block level, if the reference picture of the neighboring block A is different from the collocated picture, the motion vector of the neighboring block A may be scaled based on a temporal motion vector scaling method. And, the scaled motion vector of the neighboring block A can be used in ATMVP. FIG. 17 is a diagram illustrating a method of deriving an Advanced Temporal Motion Vector Prediction (ATMVP) candidate according to an embodiment to which the present invention is applied. Referring to FIG. 17, in one embodiment of the present invention, a TMVP using a right-bottom block of a current block or a temporal neighboring block (or already a motion vector) at a center position of the current block Since it does not reflect the motion in the picture, the encoder / decoder can use the motion vector of this drawing at the location indicated by the motion vector of the neighboring block as the MVP.

For example, the encoder / decoder may find the motion vector of the first available spatial neighbor block while checking as in the merge candidate construction order shown in FIG. 17. The position indicated by the motion vector in the reference picture may be derived as col-PB (ie, an ATMVP candidate).

The motion vector may be used as a motion vector of a corresponding block in each subblock unit. In this case, when a motion vector does not exist in a specific subblock, the subvector in which the motion vector of the center block located in the center of the corresponding block is not available is available. 2019/194499 1 »（： 1/10 公 019/003805

It can be used as a motion vector for 55 blocks, and it can be stored as a representative motion vector.

Temporal motion vector data storage reduct

In one embodiment of the present invention, a method of reducing temporal motion vector storage based on motion vector data of spatial candidates is proposed for temporal motion vector data compression.

18 and 19 are diagrams illustrating a method of compressing temporal motion vector data and positions of spatial candidates used therein according to an embodiment to which the present invention is applied.

Referring to FIG. 18, in the embodiment of the present invention, if a spatial candidate is predicted by inter prediction, a motion vector of the spatial candidate may be set as a basic motion vector for compression. For example, up to five spatial candidates may be used as reference temporal motion information for deriving a fundamental temporal motion vector. In one embodiment, the five spatial candidates may be set as shown in FIG. 19.

In addition, temporal motion vector data may be compressed based on the motion vectors of the spatial candidates. The order of searching for spatial candidates may be as shown in FIG. 18. The spatial candidates may be identified in the order of the center block C, the upper left block TL, the upper right block TR, the lower left block BL, and the lower right block BR. This is just one embodiment, and the present invention is not limited thereto, and the other possible combination order is Can be applied.

First, the encoder / decoder may check whether the center block is inter-predicted. If the center block is inter-predicted, the encoder / decoder may set the center block (its motion vector as a default for motion vector prediction). have.

If the center block is not inter predicted, the encoder / decoder may check whether the upper left block TL is inter predicted. If the upper left block TL is inter predicted, the encoder / decoder encodes the encoder. TL) may be set as a default for motion vector prediction.

If the upper left block TL is not inter predicted, the encoder / decoder may check whether the upper right block TR is inter predicted. If the upper right block TR is inter predicted, the encoder / decoder may set the motion vector of the upper right block TR as a default for motion vector prediction. If the right upper block TR is not inter predicted, the encoder / decoder may check whether the lower left block BL is inter predicted. If the lower left block BL is inter predicted, the encoder / decoder may set a motion vector of the lower left block beauty as a default for motion vector prediction. If the lower left block BL is not inter predicted, the encoder / decoder may check whether the lower right block BR is inter predicted. If the lower right block rate is inter predicted, the encoder / decoder may set the motion vector of the lower right block BR as a default value for motion vector prediction. If the lower right block Ri inter inter prediction is not, the encoder / decoder You can set the intra mode to default.

Through the above process, the encoder / decoder can compress a default motion vector into motion information. Embodiment of Performing ATMVP Based on Adaptive Subblock Size

In one embodiment of the present invention, a method for performing ATMVP based on an adaptive subblock size is proposed. For example, the sub block size used for ATMVP derivation may be adaptively applied at the slice level.

On the other hand, if ATMVP motion information is derived in 4x4 block units, there may be a problem that motion derivation and motion compensation are performed in every 4x4 subblock unit in one ATMVP coding unit.

To solve this problem, the encoder can signal one default sub-block size used for ATMVP motion derivation to the decoder at the sequence level.

As another example, when a default sub-block size is used in the current slice, a flag may be signaled at the picture or slice level. If the flag is false, the ATMVP subblock size may be additionally signaled in the slice header. Example of Restricting an Area for Collocated Block Induction

In the present invention, the area of the collocated block for ATMVP is currently

Will contain one column of NxN blocks within the CTU and collocated picture Can be. For example, the NxN block may be a 4x4 block, but the present invention is not limited thereto.

If the ATMVP collocated block identified by the motion vector of the merge candidate is located outside the restricted area, it may be moved to be located within the restricted area. For example, it may be moved to be located at the nearest boundary within the restricted area.

Embodiment of Deriving Subblock-based Temporal Merging Candidate In an embodiment of the present invention, the encoder / decoder is configured to obtain motion information of a collocated block (or collocated subblock) in a collocated picture specified based on motion information of a spatially neighboring block. As a subblock-based temporal merging candidate, we can share in a subblock merging candidate list. In the present invention, motion information of a spatially neighboring block may be referred to as a temporal motion vector. As an embodiment, the encoder / decoder may derive a sub block based time merge candidate when the width and height of the current coding block are greater than or equal to a predetermined specific size. For example, the predetermined specific size may be eight.

As an embodiment, the encoder / decoder may set the motion information of the first spatial candidate among the available spatial candidates as a temporal motion vector. As an example, the encoder / decoder may search for available spatial candidates in the order of Al, Bl, BO, and A0. In this case, the encoder / decoder has a reference picture among the available spatial candidates. 2019/194499 1 »(： 1/10 公 019/003805

A spatial candidate identical to a collocated picture may be set as a temporal motion vector.

Also, the encoder / decoder may specify the position of a collocated block in a collocated picture using the temporal motion vector. For example, the following Equation 1 may be used.

[Equation 1]

xColCb = Clip3 (xCtb, Min (CurPicWidthlnSamplesY-1, xCtb + (1 «CtbLog2SizeY) + 3), xColCtrCb + (tempMv (this» 4))

yColCb = Clip3 (yCtb, Min (CurPicHeightlnSamplesY 一 1, yCtb + (1 «CtbLog2SizeY)-1), yColCtrCb + (tempMv [l]» 4))

Here, (xColCtrCb, yColCtrCb) represents the top-left sample position of the collocated coding block including the right porridge sample of the central position, and tempMv represents the time movement vector.

In addition, the encoder / decoder may determine a position for deriving motion information of each subblock in the current coding block on a subblock basis. In one embodiment, the location of the collocated subblock in the collocated picture may be derived using Equation 2 below.

[Equation 2]

xColSb == Clip3 (xCtb, Min (CurPicWidthlnSamplesY-1 ， xCtb + (1 «

CtbLog2SizeY) + 3), xSb + (tempMv (this> ñ 4))

yColSb = Clip3 (yCtb, Min (CurPicHeightlnSamplesY-1 ， yCtb + (1 «

2019/194499 1 »（： 1/10 公 019/003805

60, (xSb, ySb) represents the position of the current subblock.

In an embodiment, when the current collocated subblock is not available, the encoder / decoder may use the motion information of the collocated block specified using a temporal motion vector. In the present invention, it is effective to redefine candidates in the candidate list.

We propose a method for deriving an advanced temporal motion vector prediction (ATMVP) candidate. Conventional ATMVP refers to the first spatial candidate to derive a Temporal Motion Vector (TMV). In an embodiment of the present invention, the TMV may be derived by referring to the spatial candidates of the rearranged candidate list in order to obtain better compression efficiency. As described above, in the present invention, ATMVP may be referred to as a subblock-based temporal merging candidate, SbTMVP. In the present invention, the candidate list represents a motion information candidate list and may include a merge candidate list, an MVP (or AMVP) candidate list, a sub-block merge candidate list, an affine merge candidate list, and the like.

An object of the present invention is to propose a method for constructing a spatial candidate list in order to use motion information of neighboring blocks of a current block for prediction.

In addition, an object of the present invention is to signal by rearranging the order of candidate lists. Suggest ways to save bits.

It is also an object of the present invention to propose a method for deriving ATMVP-fi- using specific candidates in a reordered candidate list.

It is also an object of the present invention to propose a method of constructing a candidate list by filling in the number of allowed candidates based on rearranged candidates. 20 is a flowchart illustrating a method of constructing a candidate list using motion information of spatial neighboring blocks according to an embodiment to which the present invention is applied.

Referring to FIG. 2 ◦, in an embodiment of the present invention, the encoder / decoder may construct a spatial candidate list in order to use motion information of neighboring blocks for prediction. That is, the encoder / decoder may use motion information of neighboring blocks around the current block to derive an ATMVP candidate, and may construct a candidate list using motion information of the spatial neighboring block.

In detail, the encoder / decoder checks whether the neighboring block is an available block and, if available, adds the block as a spatial candidate to the candidate list. In this case, the encoder / decoder may check availability of the left, top, right top, bottom left, and top left spatial candidates and add them to the candidate list. For example, the positions of the left, upper, right upper, lower left and upper left spatial candidates may be the same as in FIG. 16. Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 20 is an example, and the present invention is not limited thereto. Therefore, other steps may be added in addition to each step of the flowchart illustrated in FIG. 20, and some steps may be omitted. In addition to the candidates illustrated in FIG. 20, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted.

Referring to FIG. 21, in an embodiment of the present invention, the encoder / decoder may construct a temporal candidate list to use motion information of neighboring blocks for prediction.

One . First, the encoder / decoder checks whether there is a space candidate available for ATMVP, and derives ATMVP using the motion information of the available space candidate. The encoder / decoder then adds the derived ATMVP to the candidate list. For example, the encoder / decoder may derive ATMVP with reference to the first report among the available spatial candidates.

2 . The encoder / decoder verifies that Spatial-Temporal Motion Vector Prediction (STMVP) is available and adds STMVP to the candidate list, if available. STMVP represents a sub-block unit motion vector candidate combining a spatial candidate motion vector and a temporal candidate motion vector.

3. The encoder / decoder is a combined bi-predictive 2019/194499 1 »（： 1 ^ 1 {2019/003805

63 Verify that candidates are available, and if available, add them to the candidate list.

4 . Finally, the encoder / decoder adds a zero motion vector to the candidate list.

2 and 21 described above may be performed independently, or the two embodiments may be performed in combination. For example, the encoder / decoder may add a spatial candidate to the candidate list as described with reference to FIG. 20, and then add a time candidate to the candidate list as described with reference to FIG. 21.

Hereinafter, a method of rearranging the order of candidates included in the configured candidate list will be described.

Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 21 is an example, and the present invention is not limited thereto. Accordingly, other steps may be added in addition to each step of the flowchart illustrated in FIG. 21, and some steps may be omitted. In addition to the candidates illustrated in FIG. 21, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted.

FIG. 22 is a flowchart illustrating a method of deriving motion information used for motion compensation from a candidate list based on a syntax element transmitted through a bit stream according to an embodiment to which the present invention is applied.

Referring to FIG. 22, a decoder constructs a candidate list and parses a syntax element transmitted through a bit stream. The syntax element may be a candidate index indicating motion information used for motion compensation of a current block in the candidate list. The decoder uses the candidate index signaled from the encoder to The candidate used for motion compensation is selected.

The decoder generates inter-predicted block of the current block by performing inter prediction using motion information of the selected candidate.

In this case, the configured candidates are represented by the number of different bits according to the candidate order and transmitted in the bit stream. For example, as shown in Table 2 below, assuming that the maximum number of candidates is seven, one bit for the first candidate, two bits for the second candidate, and three bits for the third candidate may be allocated.

Table 2

That is, bits allocated according to the order of the selected candidates may be different, and thus different compression efficiencies may be exhibited according to the selected candidates. For this reason, conventional candidate configurations employ a fixed order based on experimentally (or statistically) determined selection probabilities. However, in either case it is not considered a fixed probability, and in many cases it is a different choice than fixed probability. 2019/194499 1 »（： 1 ^ 1 {2019/003805

You can have 65 chance.

Accordingly, an embodiment of the present invention proposes a method of rearranging the order of candidates in a candidate list in order to remedy this problem and to achieve better compression efficiency. As an embodiment, the encoder / decoder may calculate similarity (or cost) based on the template and rearrange the candidate list based on the calculated similarity. The higher the similarity, the less cost value can be calculated.

The encoder / decoder may sort the order of the candidates by comparison (or by reference) the similarity of each candidate and allocate fewer bits in the sorted order. As another example, when the prediction is bidirectional, the encoder / decoder may rearrange the candidate list by comparing the similarities of the bidirectional reference blocks.

According to an embodiment of the present invention, by reordering candidates based on similarity, relatively few bits may be allocated to candidates having a higher selection probability, thereby increasing compression efficiency.

Referring to FIG. 23, a decoder may construct a candidate list and select an optimal candidate from a bit stream without separate syntax parsing. For example, assuming that the maximum number of candidates is seven, since the first candidate in the candidate list has the highest probability, the encoder / decoder may perform an example with reference to the first candidate.

The encoder / decoder uses the motion information of the selected candidate to perform inter prediction. 2019/194499 1 »（： 1 ^ 1 {2019/003805

66, generate an inter predicted block of the current block.

For this reason, conventional candidate configurations employ a fixed order based on experimentally (or statistically) determined selection probabilities. In either case, however, it cannot be seen as following a fixed probability, and in many cases may have a different selection probability than the fixed probability.

Accordingly, an embodiment of the present invention proposes a method of rearranging candidate order in a candidate list in order to improve this problem and to achieve better compression efficiency. In an embodiment, the encoder / decoder may calculate similarity based on the template and rearrange the candidate list based on the calculated similarity. The encoder / decoder may sort the order of the candidates by comparison (or by reference) the similarity of each candidate and allocate fewer bits in the sorted order. As another example, when the prediction is bidirectional, the encoder / decoder may rearrange the candidate list by comparing the similarity of bidirectional reference blocks.

Added in FIG. 21 described above

A candidate is a method of using motion information of a reference block indicated by motion information of a corresponding candidate with reference to a first candidate in a spatial candidate list as time motion information in units of subblocks of a current block. Because of the statistical and experimental results that the first candidate has a high probability of selection,

(Or derivation) refer to the first spatial candidate.

However, in some cases it is different from the selection probabilities derived from existing experimental results. 2019/194499 1 »（： 1 ^ 1 {2019/003805

67 may have a probability of selection. In such a case, if the spatial candidates to be referred to in selecting the candidates are selected in consideration of the selection probability, the accuracy of prediction may be further increased.

Therefore, you can rearrange the order of candidates based on a specific method and then use the first of the rearranged candidates.

Suggest a way to organize. As an embodiment, an example of a specific method may be a method of using similarity as a comparison value based on a template. Alternatively, as an example, when prediction is bidirectional, there may be a method of using similarity of bidirectional reference blocks as a comparison value. By reordering the candidates in the order of similarity based on the similarity used as the comparison value, relatively few bits can be allocated to candidates having a higher selection probability, thereby improving compression efficiency.

Through the above method, the encoder / decoder refers to the candidate having the highest similarity in the reordering list.

Candidates can be derived. It demonstrates with reference to the following drawings.

24 is a flowchart illustrating a method of constructing a motion information candidate list using a spatial candidate and a temporal candidate and reordering candidates of the configured candidate list according to an embodiment to which the present invention is applied.

Referring to FIG. 24, the encoder / decoder adds available spatial neighboring blocks (or spatial candidates) (e.g., left, upper right upper, lower left, upper left spatial neighboring blocks) to the candidate list. In this case, the method described above with reference to FIG. 20 may be applied. Duplicate explanations will be omitted.

An encoder / decoder is a candidate constructed (or generated) using spatial candidates. Reorder candidates in the list. In an embodiment, the encoder / decoder may calculate similarity based on the template and rearrange the candidate list based on the calculated similarity. The encoder / decoder may sort the order of the candidates by comparison (or by reference) with the similarity of each candidate and allocate fewer bits in the sorted order. As another example, when the prediction is bidirectional, the encoder / decoder may rearrange the candidate list by comparing the similarity of bidirectional reference blocks.

The encoder / decoder checks whether there is a space candidate available for ATMVP, and derives ATMVP using the motion information of the available space candidates. The encoder / decoder then adds the derived ATMVP to the candidate list. In this embodiment, the encoder / decoder may derive an ATMVP with reference to the first candidate among the available spatial candidates in the reordered candidate list.

The encoder / decoder verifies that Spatial-Temporal Motion Vector Prediction (STMVP) is available and adds STMVP to the candidate list, if available. The encoder / decoder checks whether a combined bi-predictive candidate is available and adds it to the candidate list if it is available. Finally, the encoder / decoder adds zero motion vectors to the candidate list.

In one embodiment, the encoder / decoder may rearrange the added candidate list through the above steps to generate the final candidate list. As an embodiment, the encoder / decoder may calculate similarity based on the template and rearrange the candidate list based on the calculated similarity. The encoder / decoder sorts each candidate's similarity by comparison (or by reference) and compares the candidates in the sorted order. 2019/194499 1 »（： 1 ^ 1 {2019/003805

69 bits can be allocated. As another example, when the prediction is bidirectional, the encoder / decoder may rearrange the candidate list by comparing the similarities of the bidirectional reference blocks.

According to an embodiment of the invention, the table? In deriving candidates, by referring to the first candidate in the reordered candidate list by considering the probability of selection

The accuracy of prediction of the candidate can be increased.

Meanwhile, each step or candidates inserted in the flowchart shown in FIG. 24 is an example, and the present invention is not limited thereto. Therefore, other steps may be added in addition to each step of the flowchart illustrated in FIG. 24, and some steps may be omitted. In addition to the candidates illustrated in FIG. 24, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted.

FIG. 25 is a flowchart illustrating a method of constructing a motion information candidate list using a spatial candidate and a temporal candidate and reordering candidates of the configured candidate list according to an embodiment to which the present invention is applied.

Referring to FIG. 25, the encoder / decoder lists a list of available spatial neighboring blocks (or spatial candidates) (eg, left, upper right upper, lower left, upper left spatial neighboring blocks) and temporal neighboring blocks (or temporal candidates). Add to In this case, ^first, before FIG. 20, you may be applied a method described in FIGS. 21 and 24. Duplicate explanations will be omitted.

The encoder / decoder may reorder candidates in a candidate list constructed (or generated) using spatial candidates, temporal candidates, combination candidates, and zero motion vectors. 2019/194499 1 »（： 1 ^ 1 {2019/003805

In an embodiment 70, the encoder / decoder may calculate similarity based on the template and rearrange the candidate list based on the calculated similarity. The encoder / decoder may sort the order of the candidates by comparison (or by reference) the similarity of each candidate and allocate fewer bits in the sorted order. As another example, when the prediction is bidirectional, the encoder / decoder may rearrange the candidate list as a comparison value of the similarity of the bidirectional reference blocks.

Then, the encoder / decoder checks whether there is a candidate available for ATMVP and uses motion information of the available candidate.

Can be induced. And the encoder / decoder is derived

Add to candidate list. In this embodiment, the encoder / decoder refers to the first candidate among the available candidates in the reordered candidate list.

Can be induced.

Also, in one embodiment, the encoder / decoder may rearrange the candidate list added through the above steps to generate the final candidate list.

In other words, in this embodiment, the encoder / decoder

In constructing a candidate, a candidate having the highest similarity may be referred to considering not only the spatial candidate but also all candidates added to the conventional candidate list (eg, FIGS. 20 and 21). Meanwhile, each step or candidates inserted in the flowchart illustrated in FIG. 25 is an example, and the present invention is not limited thereto. Accordingly, other steps may be added in addition to each step of the flowchart illustrated in FIG. 25, and some steps may be omitted. In addition to the candidates illustrated in FIG. 25, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted. FIG. 26 is a flowchart illustrating a method of rearranging candidates in a candidate list constructed using a spatial candidate and a temporal candidate as an embodiment to which the present invention is applied.

The candidate reordering technique according to an embodiment of the present invention does not require a large amount of computation as a method of simply sorting candidates in a candidate list based on a reference value, that is, similarity. Thus, the encoder / decoder may apply a candidate reordering process for the candidate list when inserting each candidate into the candidate list. In the present embodiment, the description overlapping with the above-described FIGS. 24 and 25 will be omitted. Referring to FIG. 26, the encoder / decoder may check whether spatial candidates (eg, left, upper right upper side, lower left and upper left spatial neighboring blocks) are available, and insert the available spatial candidates into the candidate list. In this case, after inserting each candidate, the encoder / decoder may rearrange the candidates in the candidate list.

Thereafter, the encoder / decoder may check whether there is a space candidate available for ATMVP and derive the ATMVP using the motion information of the available space candidate. The encoder / decoder then adds the derived ATMVP to the candidate list. In this embodiment, the encoder / decoder may derive ATMVP with reference to the first candidate among the available candidates in the reordered candidate list. The encoder / decoder may then rearrange the candidates in the candidate list.

The encoder / decoder verifies that Spatial-Temporal Motion Vector Prediction (STMVP) is available and adds STMVP to the candidate list, if available. The encoder / decoder checks if a combined bi-predictive candidate is available and uses it. 2019/194499 1 »（： 1 ^ 1 {2019/003805

72 If possible, add to the candidate list. Finally, the encoder / decoder adds a zero motion vector to the candidate list. In this case, after inserting each candidate, the encoder / decoder may rearrange the candidates in the candidate list.

In addition, in one embodiment, if a candidate can be included in the list, the candidate may be implemented based on the similarity calculated for the candidate so that the candidates may not be rearranged every time a candidate is formed. . Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 26 is an example, and the present invention is not limited thereto. Accordingly, other steps may be added in addition to each step of the flowchart illustrated in FIG. 2, and some steps may be omitted. In addition to the candidates illustrated in FIG. 26, another candidate may be inserted into the candidate last, and an insertion process for some candidates may be omitted.

Referring to FIG. 27, the encoder / decoder may add candidates to the candidate list in the order described with reference to FIG. 25. In other words, the encoder / decoder adds available spatial neighboring blocks (or spatial candidates) (eg, left, top right, bottom left, top left spatial neighboring blocks) and temporal neighboring blocks (or temporal candidates) to the candidate list. . The encoder / decoder refers to the first candidate among the available candidates in the finally reordered candidate list.

Candidates can be derived and added to the candidate list. 2019/194499 1 »（： 1 ^ 1 {2019/003805

73 In an embodiment of the present invention, the encoder / decoder may apply a candidate reordering process for the candidate list when inserting each candidate into the candidate list. In this case, the method described above with reference to FIG. 26 may be applied, and a redundant description thereof will be omitted.

Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 27 is an example, and the present invention is not limited thereto. Therefore, other steps may be added in addition to each step of the flowchart illustrated in FIG. 27, and some steps may be omitted. In addition to the candidates illustrated in FIG. 27, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted.

FIG. 28 is a diagram to illustrate a method for constructing a candidate list in consideration of the maximum allowable number of conventional candidates in an embodiment to which the present invention may be applied.

In the conventional candidate list construction method, as shown in FIG. 28, when candidates are inserted into the candidate list in the order of spatial candidates, temporal candidates, combination candidates, and zero motion vectors, configurable candidates are sequentially inserted into the list. If a certain number of allowances was exceeded, the remaining candidates were not considered in the candidate list construction. However, if the candidate list is rearranged according to the method proposed by the present invention, more candidates may be considered, and the accuracy of prediction may be increased by configuring candidates arranged based on similarity as the number of allowed candidates.

Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 28 is an example, and the present invention is not limited thereto. Accordingly, other steps may be added in addition to each step of the flowchart shown in FIG. 28, and some steps may be omitted. 2019/194499 1 »（： 1 ^ 1 {2019/003805

74 may be. In addition to the candidates illustrated in FIG. 28, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted.

Referring to FIG. 29, the encoder / decoder applies a method described above with reference to FIGS. 20 and 21 to apply spatial candidates (ie, left, upper right upper, lower left, upper left spatial neighboring blocks) and temporal candidates (that is,

Candidates can be added to the candidate list in the combination candidate and zero motion vector order. 20 and 21 duplicated description will be omitted.

In an embodiment of the present invention, the encoder / decoder constructs the final candidate list by using the maximum number of candidates based on the priority among the candidate lists (which may be referred to as temporary candidate lists) constructed by applying the above-described steps. can do. As an example, the encoder / decoder may reorder candidates in the candidate list before determining the maximum candidate number of candidates as the final candidate list. In this case, the encoder / decoder may construct the final candidate list using the maximum number of candidates based on the priority among the rearranged candidate lists.

Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 29 is an example, and the present invention is not limited thereto. Therefore, other steps may be added in addition to each step of the flowchart illustrated in FIG. 29, and some steps may be omitted. In addition to the candidates illustrated in FIG. 29, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted. have.

Referring to FIG. 30, the encoder / decoder applies the method described above with reference to FIG. 26 to apply spatial candidates (i.e., left, upper right upper, lower left, upper left spatial neighboring blocks) and temporal candidates (i.e., ATMVP, STMVP, TMVP). Candidates can be added to the candidate list in order of combination candidates and zero motion vectors. 26 and redundant descriptions are omitted.

The encoder / decoder may apply a candidate reordering process for the candidate list when inserting each candidate into the candidate list.

In an embodiment of the present invention, the encoder / decoder constructs the final candidate list by using the maximum number of candidates based on the priority among the candidate lists (which may be referred to as temporary candidate lists) constructed by applying the above-described steps. can do. Meanwhile, each step or candidate inserted in the flowchart shown in FIG. 3 is an example, and the present invention is not limited thereto. Therefore, other steps may be added in addition to each step of the flowchart illustrated in FIG. 30, and some steps may be omitted. In addition to the candidates illustrated in FIG. 30, another candidate may be inserted into the candidate list, and an insertion process for some candidates may be omitted.

Referring to FIG. 31, FRUC (Frame-rate up) as an inter-ie mode. Suppose that conversion, affine merge, affine AMVP, intermerging, and parent mode are used. The present invention is not limited thereto, and other inter prediction modes may be added, and one or more inter prediction modes may be omitted.

In applying the inter prediction mode, the encoder / decoder may construct a candidate list for each inter prediction mode. In this case, the method described above with reference to FIGS. 20 to 30 may be applied.

The encoder / decoder may select a motion information candidate used for intra prediction of the current block from the configured candidate list. In this case, as described above with reference to FIG. 22, index information indicating a specific candidate may be signaled in the candidate list or a specific candidate may be derived at the decoder side without signaling.

The encoder / decoder may generate an inter prediction block of the current block by using the selected motion information candidate.

Embodiments of the present invention described above have been described separately for the convenience of description, but the present invention is not limited thereto. In other words, the embodiments described above with reference to FIGS. 20 to 3 may be performed independently, or one or more embodiments may be combined and performed.

Referring to FIG. 32, a decoder is mainly described for convenience of description, but the present invention is not limited thereto. The method of generating an inter prediction block according to an embodiment of the present invention may be performed in the same manner in the encoder and the decoder. The decoder checks whether the spatial neighboring block of the current block is available (S3201).

When the spatial neighboring block is available as a result of the checking, the decoder adds motion information of the available spatial neighboring block to the motion information candidate list (S3202).

The decoder checks whether a temporal neighboring block of the current block is available (S3203).

The decoder adds motion information of the available time neighboring block to the motion information candidate list when the time neighboring block is available (S32CM).

The decoder selects a candidate used for intra prediction of the current block from the motion information candidate list (S3205).

The decoder generates an example of the current block, that is, a block, using the selected candidate (S3206).

In an embodiment, adding the motion information of the temporal neighboring block to the motion information candidate list may further include adding a subblock-based temporal candidate to the motion information candidate list. The motion information of the reference block specified by the first candidate of the motion information candidate list to which the motion information of the spatial neighboring block is dominated is included in the sub-block-based temporal candidate in the reference picture (or collocated picture) of the current block. Can be derived in units of sub-blocks.

In an embodiment, motion information candidates of the temporal neighboring block are received from the motion information candidate. The adding to the list may include: reordering a motion information candidate list to which motion information of the spatial neighboring block is added based on a cost value of each candidate; And stocking a sub-block based temporal candidate to the motion information candidate list, wherein the sub-block based temporal candidate is within the reference picture of the current block, the reordered The motion information of the reference block specified by the first candidate of the motion information candidate list may be derived in sub-block units.

In an embodiment, the cost value for each candidate may be calculated based on a difference value between the template of the current block and the template of the reference block identified by the motion vector of the candidate. Alternatively, as an example, the cost value for each candidate may be calculated based on the bidirectional reference block differential value. The method may further include reordering a motion information candidate list including motion information of the spatial neighboring block and the temporal neighboring block based on a cost value of each candidate; And stocking a subblock-based temporal candidate to the motion information candidate list, wherein the sub-block based temporal candidate is the rearranged motion within a reference picture of the current block. The motion information of the reference block specified by the first candidate of the information candidate list may be derived in sub-block units.

In an embodiment, the motion information candidate list is based on a cost value of a candidate included in the motion information candidate list whenever each candidate is added. Reordering may be performed.

The method may further include reordering a motion information candidate list to which motion information of the spatial neighboring block and the temporal neighboring block is added based on a cost value of each candidate; And generating a final motion information candidate list by using the maximum number of candidates based on priority in the rearranged motion information candidate list, and selecting a candidate used for intra prediction of the current block. The step may be performed by selecting a candidate used for intra prediction of the current block from the final motion information candidate list.

In FIG. 33, for convenience of description, the inter prediction unit is illustrated as one block, but the inter prediction unit may be implemented in a configuration included in the encoder and / or the decoder.

Referring to FIG. 33, the inter prediction unit implements the functions, processes, and / or methods proposed in FIGS. 8 to 32. In detail, the inter predictor may include a spatial candidate inserter 3301, a temporal candidate inserter 3302, a candidate selector 3303, and a predictive block generator 3304.

The spatial report inserting unit 3301 checks whether a spatial neighboring block of the current block is available, and if the spatial neighboring block is available as a result of the checking, the spatial information inserting unit 3301 determines motion information of the available spatial neighboring block. Add to list The time candidate inserter 3302 checks whether a temporal neighboring block of the current block is available, and if the temporal neighboring block is available as a result of the checking, the motion candidate inserter 3302 moves the motion information of the available temporal neighboring block. To the information candidate list,

The candidate selector 3303 selects a candidate used for intra prediction of the current block from the motion information candidate list.

For example, the block generator 3304 generates a prediction block of the current block by using the selected candidate.

In an embodiment, the time candidate inserter 3302 adds a subblock-based temporal candidate to the motion information candidate list, wherein the sub-block based time candidate is a reference to the current block. Within a picture, motion information of the spatial neighboring block may be derived in sub-block units using motion information of a reference block specified by the first candidate of the motion information candidate list to which the motion information is added.

In an embodiment, the temporal candidate inserter 3302 may reorder the motion information candidate list to which motion information of the spatial neighboring block is added based on a cost value of each candidate, and then Add a subblock-based temporal candidate to the motion information candidate list, wherein the sub-block-based temporal candidate is the first of the reordered motion information candidate list within a reference picture of the current block; The motion information of the reference block specified by the candidate may be derived in units of sub-blocks. In an embodiment, the cost value for each candidate may be calculated based on a difference value between the template of the current block and the template of the reference block identified by the motion vector of the candidate. Alternatively, as an example, the cost value for each candidate may be calculated based on a difference value between bidirectional reference blocks. The reordering unit may further include reordering a motion information candidate list including motion information of the spatial neighboring block and the temporal neighboring block based on a cost value of each candidate; And a sub-block-based temporal candidate inserter for adding a sub-block-based temporal candidate to the motion information candidate list, wherein the sub-block-based temporal candidate is a reference picture of the current block. The motion information of the reference block specified by the first candidate of the rearranged motion information candidate list may be derived in sub-block units.

In an embodiment, the motion information candidate list may be rearranged based on a cost value of the candidate included in the motion information candidate list whenever each candidate is added.

The rearrangement unit may further include reordering a motion information candidate list to which motion information of the spatial neighboring block and the temporal neighboring block is added based on a cost value of each candidate; And a final candidate list generator configured to generate a final motion information candidate list by using the maximum number of candidates based on priority in the rearranged motion information report list, wherein the candidate selector comprises: the final motion information candidate. In the list, a candidate used for intra prediction of the current block may be selected. 34 shows a video coding system to which the present invention is applied. The video coding system can include a source device and a receiving device. The source device may transmit the encoded video / image information or data to a receiving device through a digital storage medium or a network in the form of a file or streaming.

The source device may include a video source, an encoding apparatus, and a transmitter. The receiving device may include a receiver, a decoding apparatus, and a renderer. The encoding device may be called a video / image encoding device, and the decoding device may be called a video / image decoding device. The transmitter may be included in the encoding device. The receiver may be included in the decoding device. The renderer may include a display unit, and the display unit may be configured as a separate device or an external component.

The video source may acquire the video / image through a process of capturing, synthesizing, or generating the video / image. The video source may comprise a video / image capture device and / or a video / image generation device. The video / image capture device may include, for example, one or more cameras, video / image archives including previously captured video / images, and the like. Video / image generation devices may include, for example, computers, tablets and smartphones, and may (electronically) generate video / images. For example, a virtual video / image may be generated through a computer or the like. In this case, the video / image capturing process may be replaced by a process of generating related data. The encoding device may encode the input video / picture. The encoding apparatus may perform a series of procedures such as prediction, transform, and quantization for compression and coding efficiency. The encoded data (encoded video / image information) may be output in the form of a bitstream.

The transmitter may transmit the encoded video / video information or data output in the form of a bitstream to the receiver of the receiving device through a digital storage medium or a network in the form of a file or streaming. The digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, and the like. The transmission unit may include an element for generating a media file through a predetermined file format, and may include an element for transmission through a broadcast / communication network. The receiver may extract the bitstream and transmit the extracted bitstream to the decoding apparatus. The decoding apparatus may decode the video / image by performing a series of procedures such as inverse quantization, inverse transformation, and prediction corresponding to the operation of the encoding apparatus.

The renderer may render the decoded video / image. The rendered video / image may be displayed through the display unit.

Referring to FIG. 35, a content streaming system to which the present invention is applied may largely include an encoding server, a streaming server, a web server, a media storage, a user device, and a multimedia input device.

The encoding server generates a bitstream by compressing content input from multimedia input devices such as a smartphone, a camera, a camcorder, etc. into digital data. It serves to transmit this to the streaming server. As another example, when multimedia input devices such as smart phones, cameras, camcorders, etc. directly generate a bitstream, the encoding server may be omitted.

The bitstream may be generated by an encoding method or a bitstream generation method to which the present invention is applied, and the streaming server may temporarily store the bitstream in the process of transmitting or receiving the bitstream.

The streaming server transmits the multimedia data to the user device based on the user's request through the web server, and the web server serves as a medium for informing the user of what service. When a user requests a desired service from the web server, the web server delivers it to a streaming server, and the streaming server transmits multimedia data to the user. In this case, the content streaming system may include a separate control server, in which case the control server serves to control the command / response between each device in the content streaming system.

The streaming server may receive content from a media store and / or an encoding server. For example, when the content is received from the encoding server, the content may be received in real time. In this case, in order to provide a smooth streaming service, the streaming server may store the bitstream for a predetermined time.

Examples of the user device include a cell phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant, a portable multimedia player, a navigation, and a slate. PC (slate PC), tablet PC (tablet PC), .ultrabook, wearable device (e.g., smartwatch, smart glass, HMD (head mounted display) )), Digital television, desktop computers, digital signage, and so on.

Each server in the content streaming system may operate as a distributed server, in which case data received from each server may be distributed.

As described above, the embodiments described herein may be implemented and performed on a processor, microprocessor, controller, or chip. For example, the functional units shown in each drawing may be implemented and performed on a computer, processor, microprocessor, controller, or chip.

In addition, the decoder and encoder to which the present invention is applied include a multimedia broadcasting transmitting and receiving device, a mobile communication terminal, a home cinema video device, a digital cinema video device, a surveillance camera, a video chat device, a real time communication device such as video communication, a mobile streaming device, Storage media, camcorders, video on demand (VoD) service providers, OTT video (Over the top video) devices, Internet streaming service providers, 3D (3D) video devices, video telephony video devices, and medical video devices. It can be used to process video signals or data signals. For example, OTT video (Over the top video) devices may include game consoles, Blu-ray players, Internet-connected TVs, home theater systems, smartphones, tablet PCs, and digital video recorders (DVRs).

In addition, the processing method to which the present invention is applied can be produced in the form of a program executed by a computer, and can be stored in a computer-readable recording medium. Multimedia data having a data structure according to the present invention can also be stored in a computer-readable recording medium. The computer readable recording medium includes all kinds of storage devices and distributed storage devices in which computer readable data is stored. The computer-readable recording medium may include, for example, a Blu-ray Disc (BD), a Universal Serial Bus (USB), a ROM, a PROM, an EPROM, an EEPROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, and an optical disc. It may include a data storage device. The computer-readable recording medium also includes media embodied in the form of a carrier wave (for example, transmission over the Internet). In addition, the bitstream generated by the encoding method may be stored in a computer-readable recording medium or transmitted through a wired or wireless communication network.

In addition, an embodiment of the present invention may be implemented as a computer program product by program code, which may be performed on a computer by an embodiment of the present invention. The program code may be stored on a carrier readable by a computer.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. There's an explicit citation in the claims. It is obvious that the claims can be combined to form embodiments or to be incorporated into new claims by post-application correction.

Embodiments according to the present invention can be implemented by various means, for example, hardware, firmware, software, or a combination thereof. For implementation in hardware, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in memory and driven by the processor. The memory may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Industrial Applicability

Above, preferred embodiments of the present invention described above are disclosed for purposes of illustration. 2019/194499 1 »（： 1/10 公 019/003805

88, those skilled in the art will be able to improve, change, replace or add various other embodiments within the spirit and scope of the present invention disclosed in the appended claims.

Claims

2019/194499 1 »（： 1 ^ 1 {2019/003805 89 【Scope of claim】

[Claim 1]

In the method for processing an image based on the inter prediction mode,

Of the current block

Checking whether a neighboring block is available;

Adding the motion information of the available spatial neighboring block to the motion information candidate list if the spatial neighboring block is available as a result of the checking;

Checking whether a time (61 0 to 1) neighboring block of the current block is available;

Adding the motion information of the available time neighboring block to the motion information candidate list if the time neighboring block is available as a result of the checking;

Selecting a candidate used for intra prediction of the current block from the motion information candidate list; And

And generating a prediction block of the current block by using the selected candidate.

[Claim 2]

The method of claim 1,

Adding the motion information of the temporal neighboring block to the motion information candidate list, Adding a subblock-based temporal candidate to the motion information candidate list,

The sub-block based temporal candidate is a sub-block using motion information of a reference block specified by a first candidate of a motion information candidate list to which motion information of the spatial neighboring block is added in a reference picture of the current block. Inter prediction mode based image processing method derived in units.

[Claim 3]

The method of claim 1,

Quoted the motion information of the temporal neighboring block to the motion information candidate list,

Reordering a motion information candidate list to which motion information of the spatial neighboring block is added based on a cost value of each candidate; and moving a subblock-based temporal candidate to the motion Adding to the information candidate list,

The sub-block based temporal merge candidate is an inter prediction derived in sub-block units using motion information of a reference block specified by a first candidate of the rearranged motion information candidate list within a reference picture of the current block. Mode based image processing method.

[Claim 4]

The method of claim 1,

A motion information candidate list to which motion information of the spatial neighboring block and the temporal neighboring block is added is based on a cost value of each candidate. Reordering 0 0: (16: 1: 丄 11 ₁ 3); And

Adding a subblock-based temporal candidate to the motion information candidate list,

The sub-block based temporal merge candidate is derived in sub-block units using motion information of a reference block specified by a first candidate of the rearranged motion information candidate list in a reference picture of the current block. Based image processing method.

[Claim 5]

The method of claim 1,

And reordering the motion information candidate list based on the cost value of the candidate included in the motion information candidate list whenever each candidate is added.

[Claim 6]

The method of claim 1,

Reordering a motion information candidate list to which motion information of the spatial neighboring block and the temporal neighboring block is added based on a cost value of each candidate; And

Generating a final motion information candidate list by using the maximum number of candidates based on priority in the rearranged motion information candidate list;

The selecting of the candidate used for intra prediction of the current block may include selecting the candidate for intra prediction of the current block from the final motion information candidate list. An inter prediction mode based image processing method performed by selecting a candidate to be used.

[Claim 7]

An apparatus for processing an image based on an inter prediction mode,

A spatial candidate inserter which checks whether a spatial neighboring block of the current block is available and adds motion information of the available spatial neighboring block to a motion information candidate list when the spatial neighboring block is available as a result of the checking ;

A time candidate for checking whether a temporal neighboring block of the current block is available and adding motion information of the available temporal neighboring block to the motion information candidate list when the temporal neighboring block is available as a result of the checking; Insert;

A candidate selecting unit for selecting a candidate used for intra prediction of the current block from the motion information candidate list; And

And a prediction block generator configured to generate a prediction block of the current block by using the selected candidate.

[Claim 8]

The method of claim 7, wherein

The time candidate insertion unit,

Add a subblock-based temporal canddate to the motion information candidate list,

The sub-block based temporal candidate is the first of a motion information candidate list to which motion information of the spatial neighboring block is added in a reference picture of the current block. An inter prediction mode based image processing apparatus derived by sub-block units using motion information of a reference block specified by a first candidate.

[Claim 9]

The method of claim 7, wherein

The time candidate insertion unit,

Reordering the motion information candidate list to which the motion information of the spatial neighboring block is added based on the cost value of each report, and subblock-based temporal candidates. To the motion information candidate list,

The sub-block based temporal merge candidate is inter prediction derived in sub-block units using motion information of a reference block specified by a first candidate of the rearranged motion information candidate list in a reference picture of the current block. Mode-based image processing device.

[Claim 10]

The method of claim 7, wherein

A reordering unit for reordering the motion information candidate list to which the motion information of the spatial neighboring block and the temporal neighboring block is added based on a cost value of each candidate; And

A sub-block based time candidate inserter for adding a subblock-based temporal candidate to the motion information candidate list,

The sub-block based time merge candidate is within a reference picture of the current block. And an inter prediction mode-based image processing apparatus derived from sub-block units using motion information of a reference block specified by a first candidate of the rearranged motion information candidate list.

[Claim 11]

The method of claim 7, wherein

And the motion information candidate list is rearranged based on a cost value of a candidate included in the motion information candidate list whenever each candidate is added.

[Claim 12]

The method of claim 7, wherein

And a final candidate list generator configured to generate a final motion information candidate list by using the maximum number of candidates based on priority in the rearranged motion information candidate list.

And the candidate selecting unit selects a candidate used for intra prediction of the current block from the final motion information candidate list.