RU2789452C2 - Method and equipment for processing of video data - Google Patents

Abstract

FIELD: video encoding/decoding.

SUBSTANCE: invention relates to the field of encoding/decoding of a video signal by means of the use of mutual prediction. A method for decoding of video data is proposed, which contains: configuration of a list of possible options of a block vectors of the current block, to which a prediction mode based on inter-block copying (hereinafter – IBC) is applied, wherein IBC mode refers to another block in the current frame, and formation of a prediction sample of the current block based on the block vector included in the list of possible options of block vectors. Configuration of the list of possible options of block vectors contains: configuration of a list of possible options of block vectors from a spatial neighboring block, to which IBC prediction mode is applied, and modification of the list of possible options of block vectors based on a possible option of history-based motion vector prediction (HVMP), to which IBC prediction mode is applied, when a number of current possible options of the list of possible options of block vectors is less than the maximum number of possible options.

EFFECT: provision of processing of video data for creation of a list of possible combination options or an option of motion vector prediction in a prediction mode based on a link to current frames (CPR) or based on IBC.

7 cl, 30 dwg

Description

The technical field to which the invention belongs

[1] The present disclosure relates to a method and apparatus for processing a video signal, and more specifically, to a method and apparatus for encoding or decoding a video signal by using inter prediction.

State of the art

[2] Compression encoding means a series of signal processing technologies for transmitting digitized information over a communication line, or technologies for storing information in a form that is suitable for a storage medium. Media including video, image, audio, and the like may be a target for compression encoding, and specifically, a technique for performing compression encoding intended for video is referred to as "video image compression".

[3] Next-generation video content is expected to have the characteristics of high spatial resolution, high frame rate, and a large number of scene representation dimensions. In order to process such content, a radical increase in storage space, storage access rate, and processing power is caused as a result.

[4] Accordingly, it is required to design an encoding tool for efficient processing of next generation video content. In particular, post-High Efficiency Video Coding (HEVC) video codec standards require more efficient prediction technologies.

The essence of the invention

Technical task

[5] The purpose of the embodiments of the disclosure is to provide a video data processing method and equipment for constructing a combination candidate list or motion vector prediction candidate in a prediction (prediction) mode based on current frame reference (CPR) or on an intra-block copy basis. (IBC) that performs inter-prediction using the current frame as the reference frame.

[6] The objectives of the disclosure are not limited to the above, and other purposes not mentioned should become apparent to those skilled in the art from the description below.

Technical solution

[7] In an aspect of an embodiment of the disclosure, a method for processing video data may comprise: configuring a list of potentially suitable options (possibilities) of the block vectors of the current block to which the intra-block copy (IBC) prediction mode is applied, and the IBC mode refers to another block in the current frame; and generating a prediction sample of the current block based on a block vector included in the block vector candidate list, wherein configuring the block vector candidate list comprises: configuring the block vector candidate list from a spatial neighboring block to which the IBC prediction mode is applied; and modifying the block vector candidate list based on the historical motion vector prediction (HVMP) candidate to which the IBC prediction mode is applied when the number of current candidates in the block vector candidate list is less than the maximum number of candidates.

[8] In an embodiment, configuring the block vector candidate list may further comprise adding a null vector to the modified block vector candidate list when the number of current candidates in the modified block vector candidate list is less than the maximum number of candidate vectors.

[9] In an embodiment, adding a null vector to the modified block vector candidate list may comprise adding a null vector to the modified block vector candidate list until the number of current candidates from the modified block vector candidate list becomes the maximum number of possible vectors. options.

[10] In an embodiment, a spatial neighbor may include at least one of a left side neighbor, a left bottom neighbor, a top side neighbor, or a right top neighbor.

[11] In an embodiment, configuring the block vector candidate list may further comprise adding to the modified block vector candidate list a pairwise candidate generated based on the combination of the block vectors included in the modified block vector candidate list.

[12] In an embodiment, the method may further comprise adding a null vector to the block vector candidate list when the number of current candidates from the vector candidate list of the block to which the pairwise opportunity is added is less than the maximum number of possibilities.

[13] In another aspect of the embodiment, the video encoding method may comprise: configuring a list of possible block vectors of the current block to which the intra-block copy (IBC) prediction mode is applied, the IBC mode referring to another block in the current frame; generating a predictive sample of the current block based on the block vector included in the list of candidate block vectors; and encoding information related to prediction of the current block, wherein configuring the block vector candidate list comprises: configuring the block vector candidate list from the spatial neighboring block to which the IBC prediction mode is applied; and modifying the block vector candidate list based on the historical motion vector prediction (HVMP) candidate to which the IBC prediction mode is applied when the number of current candidates in the block vector candidate list is less than the maximum number of candidates.

[14] In another aspect of the embodiment, the equipment for decoding video data may comprise: a storage device for storing video data; and a processor coupled to the storage device and configured to process the video data, wherein the processor is configured to: configure a list of possible block vectors of the current block to which the intra-block copy (IBC) prediction mode is applied, the IBC mode referring to another block in the current frame; and generate a prediction sample of the current block based on the block vector included in the block vector candidate list, wherein, in order to configure the block vector candidate list, the processor is configured to: configure the block vector candidate list from the spatial neighboring block to which the IBC forecasting mode is applied; and modifying the block vector candidate list based on the Historical Motion Vector Prediction (HVMP) candidate to which the IBC prediction mode is applied when the number of current candidates in the block vector candidate list is less than the maximum number of candidates.

[15] In yet another aspect of the embodiment, the video encoding equipment may comprise: a storage device for storing video data; and a processor coupled to the storage device and configured to process the video data, wherein the processor is configured to: configure a list of possible block vectors of the current block to which an intra-block copy (IBC) prediction mode is applied, the IBC mode referring to another block in the current frame; generate a predictive sample of the current block based on the block vector included in the list of candidate block vectors; and encode information related to prediction of the current block, wherein, in order to configure a block vector candidate list, the processor is configured to: configure a block vector candidate list from a spatial neighboring block to which the IBC prediction mode is applied; and modifying the block vector candidate list based on the Historical Motion Vector Prediction (HVMP) candidate to which the IBC prediction mode is applied when the number of current candidates in the block vector candidate list is less than the maximum number of candidates.

Benefits of the Invention

[16] According to an embodiment of the disclosure, when a prediction mode based on CPR (current frame reference) or IBC (intra-block copy) is applied to the current block by constructing a prediction candidate list while excluding temporal neighboring blocks relative to the current block, the combining candidate list or prediction of motion vectors can be efficiently constructed.

[17] The advantages of the disclosure are not limited to the above, and other unmentioned advantages should become apparent to those skilled in the art from the description below.

Brief description of the drawings

[18] The accompanying drawings, which are included as part of the detailed description to assist in understanding the disclosure, provide embodiments of the disclosure and describe the specifications of the disclosure along with the detailed description.

[19] FIG. 1 illustrates an example of a video coding system according to an embodiment of the disclosure.

[20] FIG. 2 is an embodiment to which the disclosure applies, and is a schematic block diagram of an encoding equipment for encoding a video signal/image signal.

[21] FIG. 3 is an embodiment to which the disclosure applies, and is a schematic block diagram of a decoding equipment for decoding a video/image signal.

[22] FIG. 4 shows an example of a block diagram of a content streaming system according to an embodiment of the disclosure.

[23] FIG. 5 shows an example block diagram of video signal processing equipment according to an embodiment of the disclosure.

[24] FIG. 6A-6D respectively illustrate examples of block partition structures according to quadtree (QT), binary tree (BT), ternary tree (TT), and asymmetric tree (AT).

[25] FIG. 7 and 8, respectively, are an inter-prediction-based video/image coding procedure and an inter-prediction unit in the coding equipment according to an embodiment of the disclosure.

[26] FIG. 9 and 10, respectively, are an inter-prediction-based video/image decoding procedure and an inter-prediction unit in the decoding equipment according to an embodiment of the disclosure.

[27] FIG. 11 illustrates an example of constructing spatial merge options for the current block.

[28] FIG. 12 is a flowchart illustrating a method for configuring a combination candidate list according to an embodiment to which the disclosure applies.

[29] FIG. 13 is a flowchart illustrating a method for configuring a prediction candidate list (MVP candidate list) according to the embodiment to which the disclosure applies.

[30] FIG. 14 and 15 show examples of a prediction unit in a coding method and video/image coding equipment based on IBC prediction according to an embodiment of the present disclosure.

[31] FIG. 16 and 17 show examples of a prediction unit in a decoding method and video/image decoding equipment based on IBC prediction according to an embodiment of the present disclosure.

[32] FIG. 18-21 show flowcharts illustrating methods for configuring an IBC join candidate list according to embodiments of the present specification.

[33] FIG. 24 and 25 show flowcharts illustrating methods for configuring a list of possible IBC joins according to embodiments of the present specification.

[34] FIG. 26 is an example of a flowchart for encoding video data according to an embodiment of the present specification.

[35] FIG. 27 is an example of a flowchart for decoding video data according to an embodiment of the present specification.

Optimal Mode for Carrying Out the Invention

[32] The following describes preferred embodiments of the disclosure with reference to the accompanying drawings. The description that follows in conjunction with the accompanying drawings is to describe exemplary embodiments of the disclosure and is not intended to describe a single embodiment in which the disclosure may be implemented. The following description includes specific details in order to provide an ideal understanding of the disclosure. However, it should be understood that the disclosure may be made without specific details to those skilled in the art. In some cases, to avoid obscuring the technical idea of the disclosure, structures or devices that are well known may be omitted or may be illustrated as a block diagram oriented to the basic functions of the structures or devices.

[33] In some cases, to avoid obscuring the technical idea of the disclosure, structures or devices that are well known may be omitted or may be illustrated as a block diagram oriented to the basic functions of the structures or devices.

[34] Additionally, although general terms currently in common use are chosen as terms in the disclosure to the greatest extent possible, a term that is arbitrarily chosen by the Applicant is used on a case-by-case basis. Since the meaning of the term is clearly described in the relevant part of the description in such a case, it should be understood that the disclosure should not simply be interpreted in terms of terms used only in the description of the disclosure, but the meaning of the terms should be ascertained.

[35] Specific terminology used in the description below may be provided to aid understanding of the disclosure. Moreover, the specific terminology may be modified into other forms within the technical scope of the disclosure. For example, signal, data, sample, frame, slice, tile, frame, block, etc. may be appropriately replaced and interpreted in each encoding process.

[36] Hereinafter, in this detailed description, "processing unit" means a unit in which an encoding/decoding processing such as prediction, transformation, and/or quantization is performed. A processing unit can be interpreted as having a meaning including a unit for the luminance signal component and a unit for the chrominance signal component. For example, a processing unit may correspond to a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), or a transformation unit (TU).

[37] In addition, the processing unit can be interpreted as a unit for the luminance signal component or a unit for the chrominance signal component. For example, a processing unit may correspond to a coding tree block (CTB), a coding block (CB), a prediction block (PU), or a transform block (TB) for the luma component. Alternatively, the processing unit may correspond to a coding tree block (CTB), a coding block (CB), a prediction block (PB), or a transform block (TB) for the chroma component. In addition, the disclosure is not limited to this, and a processing unit can be interpreted as a meaning including a unit for the luminance signal component and a unit for the chrominance signal component.

[38] In addition, the processing unit is essentially not limited to a square block and can be designed in the shape of a polygon having three or more vertices.

[39] In addition, hereinafter, in this detailed description, a pixel, a frame element, a factor (a transform factor or a transform factor after first-order transform), etc., is generally referred to as a "sample" ("discrete countdown"). In addition, the use of sampling may mean the use of a pixel value, a frame element value, a transform factor, and the like.

[40] FIG. 1 illustrates an example of a video coding system according to an embodiment of the disclosure.

[41] The video coding system may include a source device 10 and a receiver 20. The source device 10 may transmit the encoded information or video/image data to the receiver 20 in file format or streaming via storage media or a network.

[42] Source device 10 may include video source 11, encoding equipment 12, and transmitter 13. Receiver device 20 may include receiver 21, decoding equipment 22, and renderer 23. The source device may be referred to as "video/image coding equipment", and the receiving device may be referred to as "video/image decoding equipment". The transmitter 13 may be included in the coding equipment 12. The receiver 21 may be included in the equipment 22 decoding. The renderer may include a display, and the display may be configured as a separate device or an external component.

[43] The video source 11 can acquire video/image data through a video/image capturing, synthesis, or forming process. The video source may include 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, a video/image archive including previously captured videos/images, and the like. The video/image generating apparatus may include, for example, a computer, a tablet computer, and a smartphone, and may electronically generate video/image data. For example, virtual video/image data may be generated via a computer or the like, in which case, the video/image capturing process may be replaced by a linked data generation process.

[44] The encoding equipment 12 may encode the input video/image. The encoding equipment 12 may perform a series of procedures such as prediction, transformation, and quantization for compression and encoding efficiency. Encoded data (coded video/video information) may be output in the form of a bit stream.

[45] The transmitter 13 may transmit the encoded information or video/video data output in the form of a bit stream to the receiver of the receiving device via a digital storage medium or a network in a file or streaming format. Digital storage media may include various storage media such as Universal Serial Bus (USB), Secure Digital (SD), Compact Disc (CD), Digital Video Disc (DVD), BluRay Disc, hard disk drive (HDD) and solid state drive (SSD). The transmitter 13 may include an element for generating a media file via a predetermined file format, and may include an element for transmission via a broadcast/communications network. The receiver 21 may extract the bit stream and transmit it to the decoding equipment 22 .

[46] The decoding equipment 22 can decode the video/image data by performing a series of procedures such as dequantization, inverse transform, and prediction corresponding to the operations of the encoding equipment 12.

[47] The rendering unit 23 may generate a decoded video/image. The generated video/image can be displayed through the display.

[48] FIG. 2 is an embodiment to which the disclosure applies, and is a schematic block diagram of an encoding equipment for encoding a video signal/image signal.

[49] Referring to FIG. 2, the encoding equipment 100 may be configured to include an image separation unit 110, a subtractor 115, a transformer 120, a quantizer 130, a dequantizer 140, an inverse transformer 150, an adder 155, a filter 160, a memory 170, inter prediction unit 180, intra prediction unit 185, and entropy encoder 190. Inter prediction unit 180 and intra prediction unit 185 may typically be referred to as a "prediction unit". In other words, the prediction module may include an inter prediction module 180 and an intra prediction module 185 . Transformer 120, quantizer 130, dequantizer 140, and inverse transform 150 may be included in the residual processor. The residual processor may further include subtractor 115. In one embodiment, image separation module 110, subtractor 115, transform 120, quantizer 130, dequantizer 140, inverse transform 150, adder 155, filter 160, inter prediction module 180, internal prediction and entropy encoder 190 may be configured as a single hardware component (eg, encoder or processor). In addition, the storage device 170 may be configured with a hardware component (eg, a storage device or a digital storage medium) in the embodiment. In addition, memory 170 may include a decoded frame buffer (DPB).

[50] The image separating unit 110 may separate an input image (either a frame or a picture) input to the encoding equipment 100 into one or more processing units. For example, a processing unit may be referred to as a "coding unit (CU)". In this case, a coding unit may be recursively split from a coding tree unit (CTU) or a largest coding unit (LCU) based on a quadtree binary tree (QTBT) structure. For example, one coding unit may be split into multiple coding units of greater depth based on a quadtree structure and/or a binary tree structure. In this case, for example, a quadtree structure may be applied first, and then a binary tree structure may be applied. Alternatively, a binary tree structure may be applied first. The encoding procedure according to the disclosure may be performed based on a final coding unit that is no longer split. In this case, the largest coding unit may be directly used as the final coding unit based on the coding efficiency according to the image characteristic, or the coding unit may be recursively split into larger depth coding units as needed. Accordingly, a coding unit having an optimal size can be used as a final coding unit. In this case, the encoding procedure may include a procedure such as prediction, transformation, or restoration, which is described below. In another example, the processing unit may further include a prediction unit (PU) or a transformation unit (TU). In this case, each of the prediction unit and the transformation unit may be partitioned or segmented from each final coding unit. The prediction unit may be a unit for selective prediction, and the transform unit may be the unit from which the transform coefficient is extracted and/or the unit in which the residual signal is extracted from the transform coefficient.

[51] The unit can be used interchangeably with a block or zone according to the circumstances. In general, the MxN block may indicate a set of samples configured with M columns and N rows or a set of transform coefficients. In general, a sample may indicate a pixel or a pixel value, and may indicate only a pixel/pixel value of a luma component, or only a pixel/pixel value of a chroma component. In a sample, one frame (or image) can be used as a term corresponding to a pixel or pel.

[52] The encoding equipment 100 can generate a residual signal (residual block or residual sample array) by subtracting the prediction signal (predicted block or predictive sample array) output by the inter prediction unit 180 or intra prediction unit 185 from the input image signal (original block or an array of initial samples). The generated residual signal is transmitted to the converter 120. In this case, as illustrated, a unit in which a prediction signal (a prediction block or an array of predictive samples) is subtracted from an input image signal (a source block or an array of original samples) in the encoding equipment 100 may be called " subtractor 115". The prediction module may perform prediction on a target processing block (hereinafter, the current block), and may generate a prediction block including prediction samples for the current block. The prediction module may determine whether intra prediction is applied or inter prediction is applied in the current block or CU. The prediction module may generate various pieces of prediction information such as prediction mode information as described below in the description of each prediction mode, and may transmit the information to the entropy encoder 190. The prediction information may be encoded in the entropy encoder 190 and may be output in the form of a bitstream. .

[53] Intra prediction module 185 may predict the current block with reference to samples within the current frame. The reference samples may be located such that they are adjacent to the current block, or may be spaced apart from the current block, depending on the prediction mode. In intra prediction, the prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The non-directional mode may include, for example, a DC mode and a planar mode. The angle mode may include 33 angle prediction modes or 65 angle prediction modes, for example, depending on the precise prediction direction degree. In this case, angle prediction modes greater than or less than 33 angle prediction modes or 65 angle prediction modes, for example, may be used depending on the configuration. The intra prediction unit 185 may determine the prediction mode applied to the current block using the prediction mode applied to the adjacent block.

[54] The inter prediction unit 180 may derive a predicted block for the current block based on a reference block (reference sample array) indicated by a motion vector for the reference frame. In this case, in order to reduce the amount of motion information transmitted in the inter-prediction mode, the motion information may be predicted as a block, sub-block, or unit of samples based on the correlation of the motion information between the adjacent block and the current block. The motion information may include a motion vector and a reference frame index. The motion information may further include inter-prediction direction information (L0 prediction, L1 prediction, or bi-prediction). In the case of inter prediction, the neighbor block may include a spatial neighbor present in the current picture and a temporal neighbor present in the reference picture. The reference frame including the reference block and the reference frame including the temporal neighbor block may be the same or different. The temporary neighbor block may be called a "collocated reference block" or "collocated CU (colCU)". A reference frame including a temporal adjacent block may be referred to as a "collocated frame (colPic)". For example, inter-prediction module 180 may configure a list of motion information candidates based on neighboring blocks, and generate information indicating which candidate is used to derive the motion vector and/or the reference frame index of the current block. Inter prediction may be performed based on various prediction modes. For example, in the case of the skip mode and the merge mode, the inter prediction unit 180 may use the neighboring block motion information as the current block motion information. In the case of the skip mode, unlike the combine mode, the residual signal may not be transmitted. In the case of a motion vector prediction (MVP) mode, a neighboring block's motion vector may be used as a motion vector predictor. The motion vector of the current block may be indicated by signaling the motion vector difference.

[55] The predictive signal generated through the inter prediction module 180 or the intra prediction module 185 may be used to generate a recovered signal or a residual signal.

[56] Converter 120 may generate transform coefficients by applying a transform circuit to the residual signal. For example, the transform circuit may include at least one of discrete cosine transform (DCT), discrete sine transform (DST), Karhunen-Loeve transform (KLT), graph-based transform (GBT), or conditionally non-linear transform (CNT). ). In this case, GBT means a transformation obtained from a graph if the relationship information between pixels is represented as a graph. CNT means the transformation obtained based on the predictive signal generated using all previously reconstructed pixels. In addition, the transformation process may be applied to pixel blocks having the same size of a square shape, or may be applied to blocks having variable sizes of a non-square shape.

[57] The quantizer 130 may quantize the transform coefficients and pass them to the entropy encoder 190. The entropy encoder 190 may encode the quantized signal (information regarding the quantized transform coefficients) and output it in the form of a bitstream. The information regarding the quantized transform coefficients may be referred to as "residual information". The quantizer 130 may repackage the quantized transform coefficients of the block form into a one-dimensional vector form based on the coefficient scan sequence, and may generate information on the quantized transform coefficients based on the quantized transform coefficients of the one-dimensional vector form. Entropy encoder 190 may perform various coding techniques such as exponential Golomb coding, context adaptive variable length coding (CAVLC), and context adaptive binary arithmetic coding (CABAC). Entropy encoder 190 may encode information (eg, syntax element values) needed to reconstruct video/images, in addition to quantized transform coefficients together or separately. Encoded information (eg, encoded video/image information) may be transmitted or stored in a network abstraction layer (NAL) unit in the form of a bitstream. The bit stream may be transmitted over a network or may be stored on a digital storage medium. In this case, the network may include a broadcast network and/or a communication network. The digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD. A transmitter (not illustrated) that transmits the signal output by the entropy encoder 190 and/or a store (not illustrated) for storing the signal may be configured as an internal/external element of the encoding equipment 100, or the transmitter may be an element of the entropy encoder 190.

[58] The quantized transform coefficients output by quantizer 130 may be used to generate a predictive signal. For example, the residual signal may be recovered by applying dequantization and inverse transform to the quantized transform coefficients via dequantizer 140 and inverse transform 150 in the loop. The summer 155 may add the recovered residual signal to the prediction signal output by the inter prediction unit 180 or the intra prediction unit 185, so that a recovered signal (frame recovered, block recovered, or recovered sample array) may be generated. The predicted block may be used as the reconstructed block if there is no remainder for the target processing block, as is the case when the skip mode is applied. The adder 155 may be referred to as a "recovery module" or "recovery block generator". The generated recovered signal may be used to intra-predict the next target processing unit within the current frame, and may be used to inter-predict the next frame through filtering as described below.

[59] Filter 160 may improve subjective/objective frame quality by applying filtering to the reconstructed signal. For example, filter 160 may generate a modified reconstructed frame by applying various filtering techniques to the reconstructed frame. The modified reconstructed frame may be stored in DPB 170. Various filtering techniques may include, for example, deblocking filtering, sampled adaptive offset, adaptive loop filter, and bilateral filter. The filter 160 may generate various pieces of information for filtering, as described below in the description of each filtering method, and may pass them to the entropy encoder 190. The filtering information may be encoded by the entropy encoder 190 and output in the form of a bit stream.

[60] The modified reconstructed frame transmitted to the DPB 170 may be used as a reference frame in the inter prediction module 180. The encoding equipment can eliminate the prediction mismatch in the encoding equipment 100 and the decoding equipment, and improve encoding efficiency if inter prediction is applied.

[61] The DPB 170 may store the modified reconstructed frame to use the modified reconstructed frame as a reference frame in the inter prediction module 180.

[62] FIG. 3 is an embodiment to which the disclosure applies, and is a schematic block diagram of a decoding equipment for decoding a video/image signal.

[63] Referring to FIG. 3, the decoding equipment 200 may be configured including an entropy decoder 210, a dequantizer 220, an inverse transform 230, an adder 235, a filter 240, a memory 250, an inter prediction unit 260, and an intra prediction unit 265. The inter prediction module 260 and the intra prediction module 265 may be collectively referred to as a "prediction module". Thus, the prediction module may include an inter prediction module 180 and an intra prediction module 185 . Dequantizer 220 and inverse converter 230 may be collectively referred to as a "residual processor". Thus, the residual processor may include a dequantizer 220 and an inverse transform 230. Entropy decoder 210, dequantizer 220, inverse transform 230, adder 235, filter 240, inter prediction unit 260, and intra prediction unit 265 may be configured as a single hardware component ( eg, decoder or processor) according to an embodiment. Moreover, the decoded frame buffer 250 may be configured with a hardware component (eg, memory or digital storage medium) in the embodiment. The storage device 250 may include a DPB 175 and may be configured with a digital storage medium.

[64] When a bitstream including video/image information is input, the decoding equipment 200 may reconstruct the image according to the video/image information processing process in the encoding equipment of FIG. 2. For example, the decoding equipment 200 may perform decoding using the processing unit used in the encoding equipment. Accordingly, the processing unit for decoding, for example, may be a coding unit. The coding unit may be partitioned from the coding tree unit or the largest coding unit depending on the quadtree structure and/or the binary tree structure. In addition, the reconstructed image signal decoded and output via the decoding equipment 200 can be reproduced via the playback device.

[65] The decoding equipment 200 may receive a signal output by the encoding equipment of FIG. 1 in the form of a bit stream. The received signal may be decoded via entropy decoder 210. For example, entropy decoder 210 may extract information (eg, video/image information) for image recovery (or frame recovery) by parsing the bit stream. For example, entropy decoder 210 may decode information in the bitstream based on an encoding method such as Exponential Golomb, CAVLC, or CABAC coding and may output a syntax element value for restoring images or quantized values of transform coefficients relative to the remainder. More specifically, in the CABAC entropy decoding method, a bin corresponding to each syntax element may be received from a bit stream, a context model may be determined using decoding target syntax element information and decoding information of a neighboring and target decoding block, or symbol/grant element information, decoded in the previous step, the probability that a bin occurs may be predicted based on a certain context model, and a character corresponding to the value of each syntax element may be generated by performing arithmetic decoding on the bin. In this case, in the CABAC entropy decoding method, after the context model is determined, the context model may be updated using the character/bin information decoded for the context model of the next character/bin. Information regarding prediction from the information decoded in the entropy decoder 2110 may be provided to a prediction module (inter prediction module 260 and intra prediction module 265). Parameter information associated with the residual value for which entropy decoding is performed in the entropy decoder 210, i. e. with quantized transform coefficients may be input to the dequantizer 220. In addition, information regarding filtering from the information decoded in the entropy decoder 210 may be provided to the filter 240. Meanwhile, a receiver (not illustrated) that receives a signal output by the encoding equipment, may be further configured as an internal/external element of the decoding equipment 200, or the receiver may be an element of the entropy decoder 210.

[66] The dequantizer 220 may dequantize the quantized transform coefficients and output the transform coefficients. The dequantizer 220 may recompose the quantized transform coefficients into a two-dimensional block form. In this case, the reassembly may be performed based on the coefficient scan sequence performed in the encoding equipment. The dequantizer 220 may perform dequantization on the quantized transform coefficients using a quantization parameter (eg, quantization step size information) and may obtain the transform coefficients.

[67] The inverse transform 230 may output a residual signal (residual block or array of residual samples) by applying an inverse transform to the transform coefficients.

[68] The prediction module may perform prediction for the current block and may generate a predicted block including prediction samples for the current block. The prediction module may determine whether intra prediction is applied or inter prediction is applied to the current block based on the prediction regarding information output by the entropy decoder 210, and may determine the detailed intra/inter prediction mode.

[69] The intra prediction module 265 may predict the current block with reference to samples within the current frame. The reference samples may be located such that they are adjacent to the current block or may be spaced apart from the current block depending on the prediction mode. In intra prediction, the prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The intra prediction unit 265 may determine the prediction mode applied to the current block by using the prediction mode applied to the adjacent block.

[70] The inter prediction unit 260 may derive a predicted block for the current block based on a reference block (reference sample array) indicated by a motion vector for the reference frame. In this case, in order to reduce the amount of motion information transmitted in the inter-prediction mode, the motion information may be predicted as a block, sub-block, or unit of samples based on the correlation of the motion information between the adjacent block and the current block. The motion information may include a motion vector and a reference frame index. The motion information may further include inter-prediction direction information (L0 prediction, L1 prediction, or bi-prediction). In the case of inter prediction, the neighbor block may include a spatial neighbor present in the current picture and a temporal neighbor present in the reference picture. For example, inter-prediction module 260 may configure a motion information candidate list based on neighboring blocks, and derive the current block's motion vector and/or reference frame index based on the received candidate selection information. Inter prediction may be performed based on various prediction modes. The prediction-related information may include information indicating the inter-prediction mode for the current block.

[71] The adder 235 may generate a reconstructed signal (recovered frame, reconstructed block, or array of reconstructed samples) by summing the obtained residual signal with a predictive signal (predicted block or array of predictive samples) output by inter prediction module 260 or intra prediction module 265. The predicted block may be used as the reconstructed block if there is no remainder for the target processing block, as is the case when the skip mode is applied.

[72] The adder 235 may be referred to as a "recovery module" or "recovery block generator". The generated recovered signal may be used to intra-predict the next target processing unit within the current frame, and may be used to inter-predict the next frame through filtering as described below.

[73] Filter 240 may improve subjective/objective frame quality by applying filtering to the reconstructed signal. For example, filter 240 may generate a modified reconstructed frame by applying various filtering methods to the reconstructed frame, and may pass the modified reconstructed frame to DPB 250. Various filtering methods, for example, may include deblocking filtering, sampled adaptive offset (SAO), adaptive loop filter (ALF) and bilateral filter.

[74] The reconstructed frame transmitted (modified) to the decoded frame buffer 250 may be used as a reference frame in the inter prediction module 260 .

[75] In the disclosure, the embodiments described in the filter 160, the inter prediction unit 180, and the intra prediction unit 185 of the encoding equipment 100 may be applied to the filter 240, the inter prediction unit 260, and the intra prediction unit 265 of the decoding equipment 200, respectively, identically or based on matching.

[76] [77] FIG. 4 shows a block diagram of a content streaming system according to an embodiment of the disclosure.

[78] The content streaming system to which the disclosure applies may include an encoding server 410, a streaming server 420, a web server 430, a media storage 440, a user device 450, and a media input device 460.

[79] The encoding server 410 may compress content input from media input devices such as a smartphone, camera, camcorder, etc. into digital data so as to form a bitstream and transmit it to the streaming server 420. As for another example, when media input devices 460 such as a smartphone, camera, and camcorder directly generate a bitstream, the encoding server 410 may be omitted.

[80] The bit stream may be generated by the encoding method or the bit stream generation method to which the disclosure applies, and the stream server 420 may temporarily store the bit stream in the process of transmitting or receiving the bit stream.

[81] The streaming server 420 transmits media data to the user device 450 based on the user's request through the web server 430, and the web server 430 serves as an intermediary to inform the user as to which service is present. When a user requests a desired service via the web server 430, the web server 430 delivers it to the streaming server 420, and the streaming server 420 transmits the media data to the user. At this time, the content streaming system may include a separate control server, in which case the control server serves to manage commands/responses between devices in the content streaming system.

[82] The streaming server 420 may receive content from the media store 440 and/or the encoding server 410 . For example, streaming server 420 may receive, in real time, content from encoding server 410. In this case, in order to transparently provide the service, the stream server 420 may store the bitstream for a predetermined time.

[83] For example, the user device 450 may include a mobile phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable media player (PMP), a navigation terminal, a stylus tablet PC, a tablet PC, ultrabook, wearable device (e.g. smart watch, smart glasses, head-mounted display (HMD), digital TV, desktop computer and digital signage system.

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

[85] FIG. 5 shows an example block diagram of video signal processing equipment according to an embodiment of the disclosure. The video signal processing equipment may correspond to the encoding equipment 100 of FIG. 2 or the decoding equipment 200 of FIG. 3.

[86] The video signal processing equipment 500 according to an embodiment of the disclosure may include a video memory 520 and a video signal processor 510 when combined with the memory 520.

[87] The processor 510 according to an embodiment of the disclosure may be configured with at least one processing circuit for processing a video signal, and may process the video signal by executing instructions for encoding or decoding the video signal. Thus, processor 510 may encode the original video signal or decode the encoded video signal by performing the encoding or decoding methods described below.

[88] The video/image coding method according to this document may be performed based on various detailed technologies, and each detailed technology is given as follows. It should be apparent to those skilled in the art that the techniques described below may be associated with procedures such as prediction, residual processing (transformation, quantization, etc.), syntax encoding, filtering, segmentation/segmentation, and etc. in the video/image encoding/decoding procedure described above and/or below.

[89] FIG. 6 shows embodiments to which the disclosure applies. Fig. 6A-6D respectively illustrate examples of block partition structures according to quadtree (QT), binary tree (BT), ternary tree (TT), and asymmetric tree (AT).

[90] When encoding video, one block may be split based on QT. In addition, one subblock split using QT can be further split recursively using QT. A blocklist that is no longer QT-partitioned may be partitioned by at least one of BT, TT, or AT. BT can have two types of partitioning: horizontal BT (2NxN, 2NxN) and vertical BT (Nx2N, Nx2N). TT can have two types of partitioning: horizontal TT (2Nx1/2N, 2NxN, 2Nx1/2N) and vertical TT (1/2Nx2N, Nx2N, 1/2Nx2N). AT can have four split types: AT horizontal up (2Nx1/2N, 2Nx3/2N), AT horizontal down (2Nx3/2N, 2Nx1/2N), AT vertical left (1/2Nx2N, 3/2Nx2N), AT right vertically (3/2Nx2N, 1/2Nx2N). Each BT, TT, AT can additionally be split recursively using BT, TT, AT.

[91] FIG. 6A shows an example of QT segmentation. Block A can be split into four sub-blocks A0, A1, A2 and A3 by means of QT. Subblock A1 can be split into four subblocks B0, B1, B2 and B3 again by QT.

[92] FIG. 6B shows an example of BT segmentation. Block B3, which is no longer partitioned by QT, can be partitioned into vertical BT (C0, C1) or horizontal BT (D0, D1). As a C0 block, each subblock can further be split recursively in the form of a horizontal BT (E0, E1) or a vertical BT (F0, F1).

[93] FIG. 6C shows an example of TT segmentation. Block B3, which is no longer split by QT, can be split into vertical TT (C0, C1, C2) or horizontal TT (D0, D1, D2). As a block C1, each sub-block can further be recursively split in the form of a horizontal TT (E0, E1, E2) or a vertical TT (F0, F1, F2).

[94] FIG. 6D shows an example of AT segmentation. Block B3, which is no longer partitioned by QT, can be partitioned into vertical AT (C0, C1) or horizontal AT (D0, D1). As a block C1, each sub-block can optionally be split recursively in the form of horizontal AT (E0, E1) or vertical TT (F0, F1).

[95] Meanwhile, BT-, TT-, and AT-segments can be used together to segment a block. For example, a subblock split by BT may be split by TT or AT. In addition, a subblock split by TT may be split by BT or AT. A subblock split by AT may be split by BT or TT. For example, after a horizontal BT split, each sub-block may be split into a vertical BT, or after a vertical BT split, each sub-block may be split into a horizontal BT. The cases have different partitioning order, but the final partitioning forms are identical.

[96] In addition, when a block is split, the order in which the block is searched can be specified in various ways. In general, the search operation is performed from left to right and from top to bottom. Performing a search in a block may mean the order of determining whether or not to further split each sub-block of the split, or the encoding order of the corresponding sub-blocks when the block is no longer split, or the search order when the sub-blocks refer to information of other adjacent blocks.

[97] Transformation may be performed for each processing unit (or transformation unit) divided by a segmentation structure as shown in FIG. 6A-6D, and in particular, the transformation matrix may be applied separately to each row direction and column direction. According to an embodiment of the disclosure, different types of transformations may be used depending on the length in the row direction or in the column direction of the processing unit (or transformation unit).

[98] FIG. 7 and 8, respectively, are an inter-prediction-based video/image coding procedure and an inter-prediction unit in the coding equipment according to an embodiment of the disclosure.

[99] The encoding equipment 100 performs inter prediction for the current block (S710). The encoding equipment 100 may extract the inter-prediction mode and motion information of the current block, and may generate prediction samples of the current block. In this case, the procedure for determining the inter-prediction mode, extracting the motion information, and generating the prediction samples may be performed simultaneously, and any procedure may be performed before the other procedure. For example, the inter-prediction unit 180 of the encoding equipment 100 may include a prediction mode determination unit 181, a motion information extraction unit 182, and a prediction sample extraction unit 183. The prediction mode determination module 181 may determine the prediction mode for the current block. The motion information extractor 182 may extract the motion information of the current block. Predictive sample extractor 183 may extract predictive samples of the current block. For example, the inter-prediction unit 180 of the encoding equipment 100 may search a given area (search area) for reference frames for a block similar to the current block through motion estimation, and may extract a reference block having a minimum difference or a difference of a given reference value or less relative to the current block. The inter prediction unit 180 may derive a reference frame index indicating a reference frame in which the reference block is located based on the reference block, and may derive a motion vector based on a position difference between the reference block and the current block. The encoding equipment 100 can determine the mode applied to the current block from various prediction modes. The encoding equipment 100 can compare RD costs for different prediction modes and can determine the optimal prediction mode for the current block.

[100] For example, if the skip mode or merge mode is applied to the current block, the encoding equipment 100 may configure a merge candidate list, which is described below, and may extract a reference block having a minimum difference or a difference of a given reference value or less relative to the current block , from the reference blocks indicated by the join candidates included in the join candidate list. In this case, the merge candidate associated with the extracted reference case block may be selected. Combining index information indicating the selected combining candidate may be generated and signaled to the decoding equipment 200 . The motion information of the current block may be extracted using the motion information of the selected join candidate.

[101] As another example, if the (A)MVP mode is applied to the current block, the encoding equipment may configure the (A)MVP candidate list, which is described below, and may use the motion vector of the Motion Vector Predictor (MVP) candidate. selected from the possible MVPs included in the list of possible (A)MVPs as the MVP of the current block. In this case, for example, a motion vector indicating a reference block retrieved by motion estimation may be used as the motion vector of the current block. The MVP candidate including the motion vector having the smallest difference relative to the motion vector of the current block, among the MVP candidates, may become the selected MVP candidate. Motion vector difference (MVD), i.e. the difference obtained by subtracting the MVP from the motion vector of the current block can be extracted. In this case, information regarding the MVD may be signaled to the decoding equipment 200 . In addition, when the (A)MVP mode is applied, the index value of the reference frame may be configured as reference frame index information and may be separately signaled to the decoding equipment.

[102] The encoding equipment 100 may extract residual samples based on the predictive samples (S720). Encoding equipment 100 can extract residual samples through a comparison between the original samples of the current block and the predictive samples.

[103] The encoding equipment 100 encodes image information including prediction information and residual information (S730). The encoding equipment may output the encoded image information in the form of a bit stream. The prediction information may include information regarding prediction mode information (eg, a skip flag, a union flag, or a mode index) and motion information as information associated with a prediction procedure. The information associated with the motion information may include candidate selection information (eg, merge index, MVP flag, or MVP index), i. e. information to extract the motion vector. In addition, the information associated with the motion information may include information regarding MVD and/or reference frame index information. In addition, the information associated with the motion information may include information indicating whether or not L0 prediction, L1 prediction, or bi-prediction is applied. The residual information is information about the residual samples. The residual information may include information regarding quantized transform coefficients for the residual samples.

[104] The output bit stream may be stored on a (digital) storage medium and transmitted to the decoding equipment, or may be transmitted to the decoding equipment via a network.

[105] Meanwhile, as described above, the encoding equipment can generate a reconstructed frame (including the reconstructed samples and the reconstructed block) based on the reference samples and the residual samples. This serves to extract, in the encoding equipment 100, prediction results identical to the prediction results performed in the decoding equipment 200 . Accordingly, the coding efficiency can be improved. Accordingly, the encoding equipment 100 may store the reconstructed frame (or the reconstructed samples and the reconstructed block) in a memory, and may use the reconstructed frame as a reference frame for inter prediction. As described above, the in-loop filtering procedure may additionally be applied to the reconstructed frame.

[106] FIG. 9 and 10, respectively, are an inter-prediction-based video/image decoding procedure and an inter-prediction unit in the decoding equipment according to an embodiment of the disclosure.

[107] The decoding equipment 200 can perform an operation corresponding to the operation performed by the encoding equipment 100. The decoding equipment 200 may perform prediction on the current block based on the received prediction information and extract prediction samples.

[108] In particular, the decoding equipment 200 may determine the prediction mode for the current block based on the received prediction information (S910). The decoding equipment 200 can determine which inter prediction mode is applied to the current block based on the prediction mode information in the prediction information.

[109] For example, the decoding equipment 200 may determine whether the combining mode or (A)MVP mode is applied to the current block based on the combining flag. Alternatively, the decoding equipment 200 may select one of various inter-prediction mode options based on the mode index. Possible options for the inter prediction mode may include skip mode, merge mode, and/or (A)MVP mode, or may include various inter prediction modes, which are described below.

[110] The decoding equipment 200 extracts motion information of the current block based on the determined inter-prediction mode (S920). For example, if a skip mode or a merge mode is applied to the current block, the decoding equipment 200 may configure a merge candidate list, which is described below, and select one of the merge candidates included in the merge candidate list. The selection of a candidate join may be performed based on the join index. The motion information of the current block may be derived from the motion information of the selected join candidate. The motion information of the selected join candidate may be used as the motion information of the current block.

[111] As another example, if the (A)MVP mode is applied to the current block, the decoding equipment 200 may configure the (A)MVP candidate list, which is described below, and may use the Motion Vector Predictor (MVP) candidate motion vector ) selected from the possible MVPs included in the list of possible (A)MVPs as the MVP of the current block. The selection may be made based on the selection information (MVP flag or MVP index). In this case, the decoding equipment 200 can extract the MVD of the current block based on the information regarding the MVD. The decoding equipment may derive a motion vector of the current block based on the MVP of the current block and the MVD. In addition, the decoding equipment can derive the index of the key frame of the current block based on the information of the index of the key frame. The frame indicated by the reference frame index in the reference frame list relative to the current block may be retrieved as the reference frame referenced for inter-prediction of the current block.

[112] Meanwhile, as described below, the motion information of the current block can be retrieved without configuring the candidate list. In this case, the motion information of the current block may be extracted according to the procedure disclosed in the prediction mode, which is described below. In this case, the option list configuration such as the configuration described above may be omitted.

[113] The decoding equipment 200 may generate prediction samples for the current block based on motion information of the current block (S930). In this case, the decoding equipment 200 may extract the reference frame based on the index of the reference frame of the current block, and may extract the prediction samples of the current block indicated in the reference frame by the motion vector of the current block. In this case, as described below, the prediction sample filtering procedure may further be performed on a part or all of the prediction samples of the current block according to the circumstances.

[114] For example, the inter-prediction unit 260 of the decoding equipment 200 may include a prediction mode determination unit 261, a motion information extraction unit 262, and a prediction sample extraction unit 263. The decoding equipment 200 may determine the prediction mode of the current block based on the prediction mode information received from the prediction mode determination unit 261, may extract motion information (motion vector and/or reference frame index) of the current block based on information related to the motion information received from a motion information extractor 262 . The predictive sample extractor 263 may extract the predictive samples of the current block.

[115] The decoding equipment 200 generates residual samples for the current block based on the received residual information (S940). The decoding equipment 200 may generate reconstructed samples for the current block based on the predictive samples and residual samples, and may generate a reconstructed frame based on the reconstructed samples (S950). Thereafter, as described above, the in-loop filtering procedure may further be applied to the reconstructed frame.

[116] As described above, the inter-prediction procedure may include a step of determining an inter-prediction mode, a step of extracting motion information according to the determined prediction mode, and a step of performing prediction (predictive sampling) based on the extracted motion information.

[117] Various inter-prediction modes may be used to predict the current block in a frame. For example, different modes may be used, such as pool mode, skip mode, MVP mode, and affine mode. The decoder-side motion vector detail (DMVR) mode and the adaptive motion vector resolution (AMVR) mode can additionally be used as additional modes. The affine mode may be referred to as "affine motion prediction mode". The MVP mode may be referred to as "Advanced Motion Vector Prediction (AMVP) mode".

[118] Prediction mode information indicating the inter-prediction mode of the current block may be signaled from the encoding equipment to the decoding equipment. The prediction mode information may be included in the bitstream and received by the decoding equipment. The prediction mode information may include index information indicating one of several possible modes. Alternatively, the inter-prediction mode may be indicated via hierarchical flag information signaling. In this case, the prediction mode information may include one or more flags. For example, the flag may further be signaled to indicate whether or not a skip mode is applied by signaling a skip flag, to indicate whether or not a join mode is applied by signaling a join flag if the skip mode is not applied, and indicating that the MVP is the mode is applied if the merge mode is not applied, or for additional identification. The affine mode may be signaled as an independent mode, or may be signaled as a mode dependent on the join mode or MVP mode. For example, the affine mode may be configured as one of a join candidate list or an MVP candidate list, as described below.

[119] The encoding equipment 100 or the decoding equipment 200 may perform inter prediction using the motion information of the current block. The encoding equipment 100 can extract the optimal motion information for the current block according to the motion estimation procedure. For example, encoding equipment 100 may search for a reference block having a similar correlation using a source block in a source frame for the current block in fractional pixels within a certain search range in the reference frame. Accordingly, the encoding equipment can extract motion information. Block similarity may be derived based on the difference between phase-based sample values. For example, block similarity may be calculated based on the sum of absolute differences (SAD) between the current block (or current block reference) and a reference block (or reference block reference). In this case, the motion information may be extracted based on the reference block having the lowest SAD in the search area. The extracted motion information may be reported to the decoding equipment using several methods based on the inter-prediction mode.

[120] If the combining mode is applied, the motion information of the current prediction block is not directly transmitted, and the motion information of the current prediction block is extracted using the motion information of the adjacent prediction block. Accordingly, the encoding equipment 100 can indicate motion information of the current prediction block by transmitting flag information to notify that the combining mode has been used and a combining index to notify which adjacent prediction block has been used.

[121] The coding equipment 100 needs to search for a join block candidate used to extract motion information of the current prediction block to perform the join mode. For example, up to a maximum of 5 possible merge block options may be used, but the disclosure is not limited to this. In addition, the maximum number of possible merge block options may be conveyed in the slice header, and the disclosure is not limited to this. After performing a merge candidate search, the encoding equipment 100 may generate a merge candidate list and may select the least cost merge candidate from the merge candidate as the final merge candidate.

[122] An embodiment of the disclosure provides various embodiments of candidate merge blocks constructing a list of merge candidates.

[123] The merge candidate list, for example, may use 5 merge block candidates. For example, 4 spatial pooling opportunities and 1 temporal pooling opportunity may be used.

[124] FIG. 11 illustrates an example of constructing spatial merge options for the current block.

[125] Referring to FIG. 11, at least one of left neighbor block A1, left lower neighbor block A2, right upper neighbor block B0, upper neighbor block B1, and left upper neighbor block B2 can be used to predict the current block. The list of join options for the current block may be configured based on the procedure shown in FIG. 12.

[126] FIG. 12 is a flowchart illustrating a method for configuring a combination candidate list according to an embodiment to which the disclosure applies.

[127] The encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatial neighboring blocks with respect to the current block, and inserts the retrieved spatial join opportunities into the join candidate list (S1210). For example, spatial neighbors may include a left bottom corner neighbor, a left neighbor, a right top corner neighbor, a top neighbor, and a left top corner neighbor of the current block. In this case, this is an example, and additional neighbor blocks such as a right neighbor block, a bottom neighbor block, and a right bottom neighbor block, in addition to the spatial neighbor blocks, may further be used as the spatial neighbor blocks. The coding equipment may detect available blocks by performing a search for spatial neighbor blocks based on priority, and may extract the motion information of the detected blocks as spatial join candidates. For example, encoding equipment 100 or decoding equipment 200 may search for the 5 blocks illustrated in FIG. 11 in sequence A1, B1, B0, A0, and B2, and can configure a list of join candidates by sequentially indexing the available candidates.

[128] The encoding equipment searches for a temporal neighboring block relative to the current block, and inserts the extracted temporal merge candidate into the merge candidate list (S1220). The temporal neighbor block may be located in a reference frame, i. e. in a frame other than the current frame in which the current block is located. The reference frame in which the temporal neighbor block is located may be referred to as a "co-located frame" or "co-located frame". You can search for a temporary neighbor block in the sequence of the right bottom corner neighbor block and the right bottom center block relative to the collocation block for the current block in the collocation. frame. Meanwhile, if motion data compression is applied, specific motion information can be stored in the colocation. frame as motion characteristic information for each given storage unit. In this case, it is not necessary to store motion information for all blocks in a given storage unit, and thus, an advantage of motion data compression can be obtained. In this case, a given storage unit may be predetermined as a 16×16 sample unit or an 8×8 sample unit, for example, or size information for a given storage unit may be signaled from the encoding equipment 100 to the decoding equipment 200. If motion data compression is applied, the motion information of the temporal neighbor block may be replaced with the characteristic motion information of the given storage unit in which the temporal neighbor block is located. Thus, in this case, in the implementation aspect, after the arithmetic right shift is performed by the given value based on the coordinates (upper left sample position) of the temporal neighbor block, and not the prediction block in which the coordinates of the temporal neighbor block are located, the temporal possible the merging case may be derived based on motion information of the prediction block that covers the location with an arithmetic shift to the left. For example, if this storage unit is a 2nx2n sample unit, assuming that the coordinates of the temporal neighbor block are (xTnb, yTnb), motion information of the prediction block located at ((xTnb>>n)<<n), (yTnb> >n)<<n)), i.e. in a modified location, may be used for a temporary merge option. Specifically, for example, if the storage unit is a 16×16 sample unit, assuming that the coordinates of the temporal neighboring block are (xTnb, yTnb), motion information of the prediction block located at ((xTnb>>4)<<4 ), (yTnb>>4)<<4)), i.e. in a modified location, may be used for a temporary merge option. Alternatively, for example, if the given storage unit is an 8×8 sample unit, assuming that the coordinates of the temporal neighboring block are (xTnb, yTnb), motion information of the prediction block located at ((xTnb>>3)<<3) , (yTnb>>3)<<3)), i.e. in a modified location, may be used for a temporary merge option.

[129] The encoding equipment may check whether or not the current number of combination possibilities is less than the maximum number of combination possibilities (S1230). The maximum number of possible combinations may be predetermined or may be signaled from the encoding equipment 100 to the decoding equipment 200 . For example, the encoding equipment 100 may generate information regarding the maximum number of possible combinations, may encode the information, and may transmit the information to the decoding equipment 200 in the form of a bitstream. If the maximum number of merge candidates fills up, the process of adding a candidate may not be performed.

[130] If, as a result of checking, the current number of combining possibilities is less than the maximum number of combining possibilities, the encoding equipment inserts the added combining candidate into the combining candidate list (S1240). The added join candidate, for example, may include ATMVP (adaptive temporal motion vector prediction), a combined bi-predictive join candidate (if the slice type for the current slice is B-type), and/or a null vector-based join candidate.

[131] FIG. 13 is a flowchart illustrating a method for configuring a prediction candidate list (MVP candidate list) according to the embodiment to which the disclosure applies.

[132] If a motion vector prediction (MVP) mode is applied, a motion vector predictor (MVP) candidate list may be generated based on the motion vector of the reconstructed spatial neighbor block (e.g., the neighbor block described in FIG. 11) and/or the motion vector, corresponding to the temporary adjacent block (or Col block). Thus, the motion vector of the reconstructed spatial neighbor block and/or the motion vector of the temporal neighbor block can be used as a motion vector predictor candidate. The prediction information may include selection information (eg, MVP flag or MVP index) indicating the best candidate motion vector predictor selected from among the motion vector predictor candidates included in the list. In this case, the prediction module may select a motion vector predictor of the current block from motion vector predictor candidates included in the motion vector candidate list using the selection information. The prediction unit of the encoding equipment 100 may calculate a motion vector difference (MVD) between the motion vector of the current block and the motion vector predictor, may encode the MVD, and may output the encoded MVD in the form of a bitstream. Thus, MVD can be obtained by subtracting the motion vector predictor from the motion vector of the current block. In this case, the decoding equipment prediction unit may obtain the motion vector difference included in the prediction information, and may extract the motion vector of the current block by summing the motion vector difference and the motion vector predictor. The decoding equipment predictor may obtain or extract a reference frame index indicating the reference frame from the prediction information. For example, the motion vector predictor candidate list may be configured as illustrated in FIG. 13.

[133] Referring to FIG. 13, the encoding equipment searches for a spatial block candidate for motion vector prediction and inserts it into the prediction candidate list (S1310). For example, the encoding equipment may search for neighboring blocks according to a predetermined search order, and add information of a neighboring block satisfying a condition for a spatial block candidate to a prediction candidate list (MVP candidate list).

[134] After constructing the block spatial candidate list, the encoding equipment compares the number of spatial possibilities included in the prediction candidate list with a preset reference number (eg, 2) (S1320). If the number of spatial candidates included in the prediction candidate list is greater than or equal to a reference number (eg, 2), the encoding equipment may complete construction of the prediction candidate list.

[135] But, if the number of spatial candidate lists included in the prediction candidate list is less than the reference number (eg, 2), the encoding equipment searches for a temporal block candidate and inserts it into the prediction candidate list (S1330), and when the temporal the block candidate is unavailable adds a motion vector zero to the prediction candidate list (S1340).

[136] A predicted block for the current block may be derived based on motion information retrieved according to the prediction mode. The prediction block may include the prediction samples (array of prediction samples) of the current block. When the motion vector of the current block indicates a fractional unit of samples, an interpolation procedure may be performed, and through it, the prediction samples of the current block may be derived based on the reference samples in the fractional unit of samples in the reference frame. When affine inter prediction is applied to the current block, predictive samples may be generated based on a motion vector in a unit of samples/subblocks. When bidirectional prediction is applied, the final predictive samples may be derived through the weighted (according to phase) sums of the predictive samples derived from the first directional prediction (eg, L0 prediction) and the predictive samples derived from the second directional prediction. Reconstruction samples and reconstruction frames may be generated based on the extracted predictive samples and, as described above, procedures such as in-loop filtering may subsequently be performed.

[137] Hereinafter in this document, prediction based on IBC (intra-block copy) is described as an example of inter-prediction. IBC can be used, for example, to encode video content for games such as SCC (Screen Content Coding). IBC essentially performs prediction within the current frame, but may be performed similar to inter-prediction in which a reference block is retrieved within the current frame. Thus, the IBC may use at least one of the inter-prediction technologies described in this document. For example, the IBC may use at least one of the methods described above to extract motion information (motion vector). The IBC may refer to the current frame and may therefore be referred to as "Current Frame Reference (CPR)". In this regard, a prediction technique using another block as a reference block in the current frame including the current block (i.e., using the current frame as the reference frame) may be referred to as "IBC" or "CPR", but embodiments of this document are not limited to specific terms and may be replaced by other appropriate terms.

[138] For IBC, encoding equipment 100 may perform block matching (BM) to extract the optimal block vector (or motion vector) for the current block (eg, CU). The extracted block vector (or motion vector) may be signaled to the decoding equipment 200 via the bit stream using a method similar to the block information (motion vector) signaling in inter prediction described above. The decoding equipment 200 may derive a reference block for the current block in the current frame via a signaled block vector (motion vector), and may derive a prediction signal (predicted block or prediction samples) for the current block through it. Here, the block vector (or motion vector) may indicate an offset from the current block to a reference block located in an already reconstructed area in the current frame. Accordingly, the block vector (or motion vector) may be referred to as a "displacement vector". Later in this document, in IBC, the motion vector may correspond to a block vector or a displacement vector. The motion vector of the current block may include a motion vector for a luminance signal component (luminance motion vector) or a motion vector for a chrominance signal component (chroma motion vector). For example, the luminance motion vector for an IBC-coded CU may be an integer unit of samples (ie, integer precision). The chrominance motion vector may also be truncated in units of integer samples. As described above, the IBC may use at least one of the inter-prediction technologies. For example, when IBC is applied in conjunction with AMVR, 1-bar and 4-bar motion vector accuracies can be switched between each other.

[139] In order to reduce storage usage and decoding complexity, a reconstructed portion of a preset area including the current CTU may be used. This limitation may allow the implementation of the IBC mode using the actual on-chip memory for hardware implementation.

[140] On the encoder side, hash-based motion prediction is performed for IBC. The encoder performs an RD check for blocks with a width not greater than 16 luma samples. For the non-merge mode, the block vector search is preferably performed using a hash-based search. If the hash does not return a valid candidate, block matching based on local lookup is performed.

[141] In a hash-based search, the hash key agreement (32-bit CRC) between the current block and the reference block is extended to all allowed block sizes. The hash key calculation for all positions in the current frame is based on 4x4 subblocks. If all the hash keys of the 4×4 sub-blocks match the hash keys at the respective reference positions for the current large size block, it is determined that the hash key matches the hash key of the reference block. If the hash keys of the set of reference blocks match the hash key of the current block, the block vector of each of the matching reference blocks is computed and one of them is selected at minimal cost.

[142] In block-by-block matching search, the search range is set to N samples left and up relative to the current block in the current CTU. At the beginning of the CTU, if there is no temporal reference frame, the value of N is initialized to 128, and if there is at least one temporal reference frame, the value of N is initialized to 64. The cache hit percentage is given as a percentage of the samples in the CTU, which demonstrates matching using a hash-based lookup. When encoding the current CTU, if the cache hit percentage is less than 5%, N is divided by two.

[143] At the CU level, the IBC mode is signaled using a flag, and may be signaled as the IBC AMVP mode or the IBC pass/merge mode as follows.

[144] IBC Skip/Merge Mode: A merge candidate index is used to indicate block vectors in a list of adjacent IBC-coded block candidates used to predict the current block.

[145] IBC AMVP mode: block vector difference is encoded similarly to motion vector difference. The block vector prediction method uses two options as predictors, and one is for the left neighbor block and the other is for the top neighbor block (in the case of IBC encoding). If both neighboring blocks are not available, the default block vector is used as a predictor. The flag is signaled to indicate the predictor index of the block vector.

[146] FIG. 14 and 15 show examples of a prediction unit in a coding method and video/image coding equipment based on IBC prediction according to an embodiment of the present disclosure.

[147] The encoding equipment 100 performs IBC prediction (IBC based prediction) for the current block (S1410). The encoding equipment 100 may extract the prediction mode and motion vector of the current block, and generate prediction samples of the current block. The prediction mode may include at least one of the above-described inter-prediction modes. Here, the prediction mode determination, motion vector extraction, and prediction sampling procedures may be performed simultaneously, or one procedure may be performed before another procedure. For example, the prediction module of the encoding equipment 100 may include a prediction mode determination module, a motion vector extraction module, and a prediction sample extraction module. Also, the prediction mode determining module may determine the prediction mode for the current block, the motion vector extractor may extract the motion vector of the current block, and the prediction sample extractor may extract the prediction samples of the current block. For example, the prediction module of the encoding equipment 100 may search for a block similar to the current block in the reconstructed area of the current frame (or in a specific area (search area) of the recovered area) by block-by-block matching (BM), and extract a reference block having a difference with respect to the current block. , equal to or less than a minimum or a certain criterion. The motion vector may be derived based on the offset difference between the reference block and the current block. The encoding equipment 100 can determine the mode applied to the current block from various prediction modes. The encoding equipment 100 can compare the RD costs of different prediction modes with each other and determine the optimal prediction mode for the current block.

[148] For example, when the skip mode or merge mode is applied to the current block, the encoding equipment 100 configures the above-described merge candidate list and extracts a reference block having a difference with respect to the current block equal to or less than a minimum or a predetermined criterion from the reference blocks specified through the possible join options included in the list of possible join options. In this case, the combining candidate associated with the extracted reference block may be selected, and combining index information indicating the selected combining candidate may be generated and signaled to the decoding equipment 200. The motion vector of the current block may be extracted by using the motion vector of the selected join candidate.

[149] As another example, when the (A)MVP mode is applied to the current block, the encoding equipment 100 constructs the above-described list of (A)MVP candidates, and uses the motion vector of the MVP candidate selected from among the motion vector predictor candidates. (MVP) included in the list of possible (A)MVP options as the 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 MVP candidate having the motion vector with the smallest difference with respect to the motion vector of the current block among the candidate MVP candidates , may represent 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, can be extracted ₀ . In this case, information regarding the MVD may be signaled to the decoding equipment 200 .

[150] The encoding equipment 100 may extract residual samples based on the predictive samples (S1420). The coding equipment 100 can extract residual samples by comparing the original samples and the predictive samples of the current block.

[151] The encoding equipment 100 encodes image information including prediction information and residual information (S1430). The encoding equipment 100 may output encoded image information in the form of a bitstream. The prediction information is information related to the prediction procedure and may include prediction mode information (eg, skip flag, merge flag, or mode index) and motion vector information. The motion vector information may include candidate selection information (eg, merge index, MVP flag, or MVP index), which is information for extracting the motion vector. In addition, the motion vector information may include the above-described MVD information. Further, the motion vector information may include information indicating whether or not L0 prediction, L1 prediction, or pairwise (bi) prediction is applied. The residual information is information about the residual samples. The residual information may include information regarding quantized transform coefficients for the residual samples.

[152] The output bit stream may be stored on a (digital) storage medium and delivered to the decoder, or may be delivered to the decoder via a network.

[153] Meanwhile, as described above, the encoding equipment 100 can generate a reconstructed frame (including reconstructed samples and reconstructed blocks) based on the reference samples and the residual samples. This serves to extract a prediction result identical to the prediction result performed by the decoding equipment 200 in the encoding equipment 100, and through it, encoding efficiency can be increased. Accordingly, the encoding equipment 100 may store the reconstructed frame (either the reconstructed samples or the reconstructed block) in a memory and use it as a reference frame for inter prediction. As described above, the in-loop filtering procedure may additionally be applied to the reconstructed frame.

[154] The IBC-based video/image decoding procedure and the prediction unit in the decoding equipment 200 may schematically include, for example, the following.

[155] FIG. 16 and 17 show examples of a prediction unit in a decoding method and video/image decoding equipment based on IBC prediction according to an embodiment of the present disclosure.

[156] The decoding equipment 200 may perform an operation corresponding to the operation performed by the encoding equipment 100. The decoding equipment 200 may perform IBC prediction for the current block based on the received prediction information and extract prediction samples.

[157] In particular, the decoding equipment 200 may determine the prediction mode for the current block based on the received prediction information (S1610). The decoding equipment 200 can determine which inter prediction mode is applied to the current block based on the prediction mode information in the prediction information.

[158] For example, the decoding equipment 200 may determine whether or not the combining mode is applied to the current block, or whether or not the (A)MVP mode is determined based on the combining flag. Or, the decoding equipment 200 may select one of various inter-prediction mode options based on the mode index. Possible options for the inter prediction mode may include skip mode, merge mode, and/or (A)MVP mode, or may include various inter prediction modes, which are described below.

[159] The decoding equipment 200 extracts the motion vector of the current block based on the determined prediction mode (S1620). For example, when the skip mode or merge mode is applied to the current block, the decoding equipment 200 may construct the above-described merge candidate list and select one merge candidate from among the merge candidates included in the merge candidate list. The selection may be performed based on the selection information (combination index) described above. The motion vector of the current block may be extracted using the motion vector of the selected join candidate. The motion vector of the selected join candidate may be used as the motion vector of the current block.

[160] As another example, when the (A)MVP mode is applied to the current block, the decoding equipment 200 may construct the above-described list of (A)MVP candidates and use the motion vector of the MVP candidate selected from the candidates included in a list of possible (A)MVP options, as the MVP of the current block. The selection may be made based on the selection information (MVP flag or MVP index) described above. In this case, the MVD of the current block may be derived based on information regarding the MVD, and the motion vector of the current block may be derived based on the MVP and MVD of the current block. In addition, the index of the key frame of the current block may be derived based on the information of the index of the key frame. The frame indicated by the reference frame index in the reference frame list for the current block may be retrieved as the reference frame referenced for inter-prediction of the current block.

[161] Meanwhile, as described above, the motion information of the current block can be extracted without configuring the candidate list, in which case, the motion vector of the current block can be extracted according to the procedure disclosed in the corresponding prediction mode. In this case, the option list configuration as described above may be omitted.

[162] The decoding equipment 200 may generate predictive samples for the current block based on the motion vector for the current block (S1630). The prediction samples of the current block may be derived using the reference block samples indicated by the motion vector of the current block in the current frame. In this case, the filtering procedure of the prediction samples for all or some of the prediction samples of the current block may further be performed.

[163] For example, the prediction module of the decoding equipment 200 may include a prediction mode determination module, a motion vector extraction module, and a prediction sample extraction module. The prediction mode determining unit determines the prediction mode for the current block based on the received prediction mode information, the motion vector extractor extracts the motion vector of the current block based on the received motion vector information, and the prediction sample extractor extracts the current block prediction samples.

[164] The decoding equipment 200 generates residual samples for the current block based on the received residual information (S940). The decoding equipment 200 may generate reconstructed samples for the current block based on the predictive samples and residual samples, and generate a reconstructed frame based on them (S1650). As described above, the in-loop filtering procedure may additionally be applied to the reconstructed frame.

[165] Hereinafter, an embodiment of the present disclosure provides a method for constructing a join candidate list (AMVP candidate list) for predicting a block to which the IBC prediction mode is applied (or to which the IBC prediction mode is not applied) . More specifically, when the IBC prediction mode is activated, a method for configuring prediction candidates for an IBC block and a non-IBC block is provided. In the following embodiment, when IBC prediction is available in a still picture or moving frame compression process, a method for constructing a prediction candidate for a block encoded/decoded in an IBC prediction mode and a prediction candidate for a block encoded/decoded in a mode other than from the IBC prediction mode is provided, and through the method, compression performance can be improved.

[166] FIG. 18-23 show examples of a flowchart for configuring IBC merge candidates and IBC AMVP candidates according to embodiments of the present specification.

[167] An embodiment of the present specification provides a method for configuring IBC association candidates and AVMP IBC candidates for a block to which the IBC mode is applied. According to this embodiment, when the IBC prediction mode is applied to the current block, a prediction candidate list is constructed using the IBC candidates to which the IBC prediction is applied. In addition, if the required number of IBC candidates is not configured, a default candidate (eg, null vector) is added to the pooling candidate/AVMP candidate list.

[168] According to an embodiment of the present specification, it is checked whether or not a candidate to be added in the IBC prediction mode is encoded when constructing a prediction candidate list for the current block to which the IBC prediction mode is applied, and when the corresponding candidate is encoded in IBC prediction mode, the corresponding candidate is added to the prediction candidate list.

[169] FIG. 18 is similar to constructing a conventional mutual predictive combining candidate list, but the temporal combining candidate is eliminated because the current frame is referred to due to IBC characteristics. Thus, a method of constructing an existing list of join candidate except for a temporary join candidate is used, and a process of checking whether or not the IBC prediction mode is applied to each candidate is added.

[170] Referring to FIG. 18, to construct a spatial opportunity, the encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatial neighboring blocks and checks whether or not the IBC mode is applied to the opportunity (corresponding to the opportunity), and adds the corresponding candidate to the join candidate list if the IBC prediction mode is applied.

[171] If the current number of possible options in the merge candidate list is less than the maximum number, the encoding equipment may search for HMVP candidates. The encoding equipment searches for candidates in a history-based motion vector prediction (HMVP) candidate list (HMVP buffer) to add an HMVP candidate, and adds the candidate to which the IBC prediction is applied to the combining candidate list. In this document, HMVP presents a method of using prediction information (motion vector, reference frame index) of another block that has already been decoded (recovered) in the current frame as information for prediction of the current block.

[172] If the current number of possibilities in the pooling candidate list is less than the maximum number, the encoding equipment may search for pairwise prediction candidates. The pairwise prediction candidates are prediction candidates generated by combining the candidates preconfigured in the prediction candidate list. For example, by combining the L0 direction block vector (motion vector) of the first candidate and the L1 direction block vector of the second candidate, a pairwise prediction opportunity can be generated. Here, the encoding equipment can check whether or not the IBC prediction is applied to the pairwise prediction candidate, and when the IBC prediction is applied, add the pairwise prediction opportunity to the join candidate list. When the IBC prediction is applied to both possibilities used to construct the pairwise prediction candidate, the IBC prediction can be said to be applied to the pairwise prediction possibility. If the current number of possible combinations in the list of possible combinations is less than the maximum number, the encoding equipment adds a null vector to the list of possible combinations.

[173] FIG. 19 is similar to configuring the existing mutual predictive join candidate list, but excludes the temporal join candidate and the HMVP candidate. The reason why HMVP possibles are excluded is because since the existing HMVP stores a certain number of possibles, when HMVP possibles are used for IBC prediction, it is necessary to store all IBC/non-IBC possibles for a limited number of possibles. options, and as a result, prediction performance or storage efficiency may be degraded during the construction of non-IBC candidate cases.

[174] Referring to FIG. 19, to construct spatial opportunities, the encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatial neighboring blocks, checks whether or not the IBC mode is applied to the opportunities, and adds the corresponding opportunity, to which the IBC forecasting mode is applied, into the list of possible combinations.

[175] If the current number of candidates in the list of combining candidates is less than the maximum number, the encoding equipment may search for a pairwise prediction candidate. The pairwise prediction candidate is a prediction candidate generated by combining the candidates preconfigured in the prediction candidate list. For example, the pairwise prediction candidate may be generated by combining the L0 direction block vector (motion vector) of the first candidate and the L1 direction block vector of the second candidate. Here, the encoding equipment can check whether or not the IBC prediction is applied to the pairwise prediction candidate, and when the IBC prediction is applied, add the corresponding pairwise prediction opportunity to the combination candidate list. When the IBC prediction is applied to both possibilities used to construct the pairwise prediction candidate, the IBC prediction can be said to be applied to the pairwise prediction possibility. If the current number of possible combinations in the list of possible combinations is less than the maximum number, the encoding equipment adds a null vector to the list of possible combinations.

[176] FIG. 20 is similar to the existing method for constructing a mutual predictive join candidate list, but is a case in which the temporal join candidate and the pairwise prediction candidate are eliminated.

[177] Referring to FIG. 20, to construct a spatial opportunity, the encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatially neighboring blocks, checks whether or not IBC mode is applied to the opportunities, and adds the corresponding opportunity, to which IBC mode is applied to the list of possible combinations.

[178] If the number of current candidates in the merge candidate list is less than the maximum number, the encoding equipment may search for HMVP candidates. The encoding equipment searches for candidates in the HMVP candidate list (HMVP buffer) to construct a history-based motion vector prediction (HMVP) candidate, and adds the candidate to which the IBC prediction is applied to the pooling candidate list. If the current number of possible combinations in the list of possible combinations is less than the maximum number, the encoding equipment adds a null vector to the list of possible combinations.

[179] FIG. 21 eliminates the pairwise prediction candidates, the HMVP candidates, and the temporal join candidate in the existing mutual predictive join candidate list construction process.

[180] Referring to FIG. 21, to construct spatial opportunities, the encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatially adjacent blocks, checks whether or not the IBC mode is applied to the opportunity, and adds the corresponding opportunity, to which IBC mode is applied to the list of possible combinations. If the current number of possible combinations in the list of possible combinations is less than the maximum number, the encoding equipment adds a null vector to the list of possible combinations.

[181] FIG. 22 eliminates the temporal merge candidate and HMVP candidates in the existing inter prediction AMVP candidate list construction process.

[182] Referring to FIG. 22, to construct spatial opportunities, the encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatially adjacent blocks, checks whether or not the IBC mode is applied to the opportunity, and adds the corresponding opportunity, to which IBC mode is applied to the list of possible AMVP options. If the current number of possibilities in the AMVP candidate list is less than the maximum number, the encoding equipment adds a null vector to the AMVP candidate list.

[183] FIG. 23 eliminates the temporal join opportunity in the existing AMVP inter prediction candidate list construction process.

[184] Referring to FIG. 23, in order to construct spatial opportunities, the encoding equipment (encoding equipment 100 or decoding equipment 200) searches for spatially adjacent blocks, checks whether or not the IBC mode is applied to the opportunity, and adds the corresponding opportunity, to which IBC mode is applied to the list of possible AMVP options.

[185] If the number of current candidates in the merge candidate list is less than the maximum number, the encoding equipment may search for HMVP candidates. The encoding equipment searches for candidates in the HMVP candidate list (HMVP buffer) to construct a history-based motion vector prediction (HMVP) candidate, and adds the candidate to which the IBC prediction is applied to the AMVP candidate list. If the current number of possible options in the merge candidate list is less than the maximum number, the encoding equipment adds a null vector to the AMVP candidate list.

[186] In addition, an embodiment of the present specification provides a method for configuring fusion/AVMP candidates for a non-IBC inter-prediction mode. It is a method for constructing a candidate list using only non-IBC candidates in a prediction candidate construction process when an inter-prediction mode (MODE_INTER) other than IBC is applied to the current block. If the required number of non-IBC candidates is not configured, it is configured as a default candidate (eg, null vector).

[187] FIG. 24 and 25 are examples of flowcharts for constructing a prediction candidate list for a block to which inter prediction is applied, according to an embodiment of the present specification.

[188] More specifically, the encoding equipment adds a candidate to the prediction candidate list only when the candidate to be added in the process of constructing the prediction candidate list is encoded with inter-prediction (non-IBC). Thus, when a candidate to be added to the prediction candidate list is encoded in IBC mode, it is not added to the candidate candidate list.

[189] FIG. 24 shows that it is checked whether the prediction mode of the candidate to be added is the IBC prediction mode in the process of constructing the join candidate list, and when the IBC prediction mode is not applied to the corresponding candidate (when inter-prediction is applied), the matching candidate is added to the join candidate list. When the candidate prediction mode to be added is the IBC prediction mode, the corresponding candidate is not added to the join candidate list.

[190] Referring to FIG. 24, to construct a spatial merging candidate, the encoding equipment searches for spatially neighboring blocks, checks whether the inter prediction mode is applied to the corresponding candidate (is the prediction mode of the corresponding spatial candidate an inter prediction mode or not) , and adds the corresponding candidate to the pooling candidate list when the inter-prediction mode is applied (when the IBC prediction mode is not applied). A candidate that has IBC prediction mode applied to it is not added to the join candidate list.

[191] If the current number of possibilities in the combination candidate list is less than the maximum number, the encoding equipment may search for a temporary prediction candidate. The temporal (TMVP) candidate represents motion information of a block co-located in a frame different from the current block. The coding equipment searches for co-located blocks (temporally adjacent blocks) in another frame to construct a temporal opportunity, and adds a temporal opportunity to which inter prediction is applied (to which no IBC prediction is applied) to the pooling candidate list.

[192] If the number of current candidates in the merge candidate list is less than the maximum number, the encoding equipment may search for HMVP candidates. The encoding equipment searches for candidates in the HMVP candidate list (HMVP buffer) to construct an HMVP candidate, and adds the candidate to which inter prediction is applied (to which IBC prediction is not applied) to the pooling candidate list. .

[193] If the current number of possibilities in the combination candidate list is less than the maximum number, the encoding equipment may search for pairwise prediction candidates. The pairwise prediction candidates are prediction candidates generated by combining the candidates preconfigured in the prediction candidate list. For example, by combining the L0 direction block vector (motion vector) of the first candidate and the L1 direction block vector of the second candidate, a pairwise prediction opportunity can be generated. Here, the encoding equipment can check whether or not inter prediction is applied (IBC prediction is not applied), and when inter prediction is applied (when IBC prediction is not applied), add the pairwise prediction candidate to the join candidate list. When inter prediction is applied to both possibilities used to construct a pairwise prediction candidate (when IBC prediction is not applied to both possibilities), it can be said that inter prediction is applied to the pairwise prediction opportunity. If the current number of possible combinations in the list of possible combinations is less than the maximum number, the encoding equipment adds a null vector to the list of possible combinations.

[194] FIG. 25 shows that it is checked whether the prediction mode of the candidate to be added is the IBC prediction mode in the process of constructing the AMVP candidate list, and when the IBC prediction mode is not applied to the corresponding candidate (when inter prediction is applied), the corresponding candidate is added to the AMVP merge candidate list. When the candidate prediction mode to be added is the IBC prediction mode, the corresponding candidate is not added to the AMVP candidate list.

[195] Referring to FIG. 25, in order to construct an AMVP spatial opportunity, the encoding equipment searches for spatially neighboring blocks, checks whether or not the inter prediction mode is applied to the corresponding candidate (is the prediction mode of the corresponding spatial opportunity or not the mutual prediction mode). prediction) and adds the corresponding candidate to the AMVP candidate list when the inter-prediction mode is applied (when the IBC prediction mode is not applied). An opportunity to which the IBC prediction mode is applied is not added to the AMVP candidate list.

[196] If the current number of possibilities in the AMVP candidate list is less than the maximum number, the encoding equipment may search for a temporary prediction opportunity. The temporal (TMVP) candidate represents motion information of a block co-located in a frame different from the current block. The encoding equipment searches for co-located blocks (temporally adjacent blocks) in another frame to construct a temporal opportunity, and adds a temporal opportunity to which inter prediction is applied (to which no IBC prediction is applied) to the AMVP candidate list.

[197] If the number of current candidates in the list of AMVP candidates is less than the maximum number, the encoding equipment may search for HMVP candidates. The encoding equipment searches for candidates in the HMVP candidate list (HMVP buffer) to construct an HMVP candidate, and adds the candidate to which inter prediction is applied (to which no IBC prediction is applied) to the AMVP candidate list. options.

[198] If the current number of candidates in the AMVP candidate list is less than the maximum number, the encoding equipment may search for pairwise prediction candidates. The pairwise prediction candidates are prediction candidates generated by combining the candidates preconfigured in the prediction candidate list. For example, by combining the L0 direction block vector (motion vector) of the first candidate and the L1 direction block vector of the second candidate, a pairwise prediction opportunity can be generated. Here, the encoding equipment can check whether or not inter prediction is applied (IBC prediction is not applied), and when inter prediction is applied (when IBC prediction is not applied), add the pairwise prediction candidate to the AMVP candidate list. When inter prediction is applied to both possibilities used to construct a pairwise prediction candidate (when IBC prediction is not applied to both possibilities), it can be said that inter prediction is applied to the pairwise prediction opportunity. If the current number of possible options in the merge candidate list is less than the maximum number, the encoding equipment adds a null vector to the AMVP candidate list.

[199] Similar to the previous embodiments, in the process of constructing a list of prediction candidate lists for a non-IBC block, of course, one can omit searching for any type of the various types of candidate candidate (spatial candidate, temporal candidate, HMVP candidate, and pairwise candidate). prediction options).

[200] FIG. 26 is an example of a flowchart for encoding video data according to an embodiment of the present specification. The operation of FIG. 26 may be performed by the inter-prediction module 180 of the encoding equipment 100 .

[201] Referring to FIG. 26, the encoding equipment 100 constructs a block vector candidate list for the current block to which the IBC prediction mode is applied referring to another block in the current frame (S2610). Here, the encoding equipment 100 may add the corresponding candidate to the block vector candidate list only when the prediction mode of the corresponding candidate to be added is the IBC prediction mode in the process of constructing the block vector candidate list (combination candidate list/ list of possible AMVP options). Thus, encoding equipment 100 can add a candidate (spatial candidate, temporal candidate, HMVP candidate, or pairwise prediction candidate) to which the IBC prediction mode is applied to the block vector candidate list.

[202] In an embodiment, to construct a block vector candidate list, encoding equipment 100 may construct a block vector candidate list from spatial neighboring blocks to which the IBC prediction mode is applied, and modify the block vector candidate list based on the HMVP candidates. options to which the IBC prediction mode is applied when the current number of options in the block vectors list of options is less than the maximum number of options.

[203] In an embodiment, if the current number of possibilities in the modified block vector candidate list is less than the maximum number of possibilities, encoding equipment 100 may add a null vector to the modified block vector candidate list. In an embodiment, encoding equipment 100 may add a null vector to the modified block vector candidate list as long as the current number of candidates is not equal to the maximum number of candidates.

[204] In an embodiment, the spatial neighbor blocks may include at least one of a left neighbor, bottom left neighbor, top neighbor, right neighbor, or right neighbor relative to the current block.

[205] In an embodiment, encoding equipment 100 may add a pairwise opportunity generated based on a combination of block vectors included in the modified block vector candidate list to the block vector candidate list.

[206] In an embodiment, if the current number of possibilities in the block vector candidate list to which the pairwise possibilities are added is less than the maximum number of possibilities, a null vector may be added to the block vector candidate list.

[207] The encoding equipment 100 generates a predictive sample for the current block based on a block vector candidate list constructed similarly to the embodiments of the present specification (S2620). For example, the encoding equipment 100 can generate a predictive sample by using a block vector (motion vector) of a candidate indicated by a union index in the block vector candidate list (combination candidate list). In particular, the predictive sample may be generated using a sample value indicated by a block vector in the current frame including the current block.

[208] In addition, with respect to a block to which an inter-prediction mode other than the IBC prediction mode is applied, the encoding equipment 100 can determine whether a candidate prediction mode is to be added to construct a block vector candidate list, a mode identical to the prediction mode for the current block (inter prediction mode), and add the corresponding candidate to the block vector candidate list in case the prediction modes are identical (are the inter prediction mode).

[209] The encoding equipment 100 encodes information related to prediction of the current block (S2630).

[210] FIG. 27 is an example of a flowchart for decoding video data according to an embodiment of the present specification. The operations of FIG. 27 may be performed by the inter-prediction module 260 of the decoding equipment 200.

[211] The decoding equipment 200 constructs a block vector candidate list for the current block to which the IBC prediction mode is applied referring to another block in the current frame (S2710).

[212] The decoding equipment 200 generates a predictive sample for the current block based on a list of possible block vectors (S2720). Here, the decoding equipment 100 may add a candidate to the block vector candidate list only when the prediction mode of the candidate to be added is the IBC prediction mode in the block vector candidate list (join candidate list/possible list) construction process. AMVP variants). Thus, the decoding equipment 200 can add a candidate (spatial candidate, temporal candidate, HMVP candidate, or pairwise prediction opportunity) to which the IBC prediction mode is applied to the block vector candidate list.

[213] In an embodiment, to construct a block vector candidate list, decoding equipment 200 may construct a block vector candidate list from the spatial neighbor blocks to which the IBC prediction mode is applied, and modify the block vector candidate list based on the HMVP candidates. options to which the IBC prediction mode is applied when the current number of options in the block vectors list of options is less than the maximum number of options.

[214] In an embodiment, if the current number of possibilities in the modified block vector candidate list is less than the maximum number of possibilities, decoding equipment 200 may add a null vector to the modified block vector candidate list. In an embodiment, encoding equipment 100 may add a null vector to the modified block vector candidate list as long as the current number of candidates is not equal to the maximum number of candidates.

[215] In an embodiment, spatial neighbor blocks may include at least one of left neighbor, bottom left neighbor, top neighbor, right neighbor, or right neighbor relative to the current block.

[216] In an embodiment, decoding equipment 200 may add a pairwise opportunity generated based on a combination of block vectors included in the modified block vector candidate list to the block vector candidate list.

[217] In an embodiment, if the current number of possibilities in the block vector candidate list to which the pairwise possibilities are added is less than the maximum number of possibilities, a null vector may be added to the block vector candidate list.

[218] The decoding equipment 200 can generate a predictive sample by using a block vector (motion vector) of a candidate indicated by a union index in the block vector candidate list (combination candidate list). In particular, the predictive sample may be generated using a sample value indicated by a block vector in the current frame including the current block.

[219] In addition, with respect to a block to which an inter-prediction mode other than the IBC prediction mode is applied, the decoding equipment 200 can determine whether the candidate prediction mode to be added to construct the block vector candidate list is itself or there is no mode identical to the prediction mode for the current block (inter prediction mode), and add the corresponding candidate to the block vector candidate list in case the prediction modes are identical (represent the inter prediction mode).

[220] Bitstream

[221] Encoded information (eg, encoded video/image information) extracted by the encoding apparatus 100 based on the above-described embodiments of the disclosure may be output in the form of a bit stream. The encoded information may be transmitted or stored in NAL units, in the form of a bit stream. The bit stream may be transmitted over a network or may be stored on a non-volatile digital storage medium. Further, as described above, the bitstream is not directly transmitted from the encoder 100 to the decoder 200, but may be streamed/downloaded via an external server (eg, a content streaming server). The network may include, for example, a broadcast network and/or a communications network, and the digital storage medium may include, for example, USB, SD, CD, DVD, Blu-ray, HDD, SSD, or various other storage media.

[222] The processing methods to which the embodiments of the disclosure apply may be created in the form of a program executable on computers and may be stored in computer-readable recording media. Multimedia data with a data structure according to the disclosure may also be stored on computer-readable recording media. Computer-readable recording media includes all kinds of storage devices and distributed storage devices that can store computer-readable data. Computer-readable recording media may include, for example, Blu-ray Discs (BDs), Universal Serial Bus (USB) drives, ROM, PROM, EPROM, EEPROM, RAM, CD-ROM, magnetic tapes, floppy disks, and optical storage device. Computer-readable recording media may include media implemented in the form of carrier waves (eg, as transmissions over the Internet). The bitstreams generated by the encoding method may be stored on computer-readable recording media or transmitted over a wired/wireless communication network.

[223] Embodiments of the disclosure may be implemented as computer programs through program codes that may be executed on computers according to an embodiment of the disclosure. The machine codes may be stored on a computer-readable medium.

[224] The above described embodiments of the disclosure may be implemented by a non-volatile computer-readable medium storing a computer-executable component configured to be executed by one or more processors of a computing device. According to an embodiment of the disclosure, a computer-executable component may be configured to determine whether or not a PCM mode is applied in which a sample value of the current block in the video data is transmitted via a bitstream, to identify a reference index associated with a reference line for intra-prediction of the current block based on not applying the PCM mode, and generating a prediction sample of the current block based on the reference sample included in the reference line associated with the reference index. Additionally, according to an embodiment of the disclosure, the computer-executable component may be configured to perform operations corresponding to the video data processing method described with reference to FIG. 13 and 14.

[225] The decoding device 200 and the encoding device 100 to which the disclosure applies may be included in a digital device. Digital devices encompass all kinds or types of digital devices capable of performing at least one of transmitting, receiving, processing and outputting, for example, data, content or services. The processing of data, content, or services by a digital device includes encoding and/or decoding the data, content, or services. Such a digital device can be paired or connected to another digital device or an external server via a wired/wireless network, data transmission or reception, or data conversion as needed.

[226] Digital devices may include, for example, network TVs, hybrid broadband TVs, smart TVs, Internet Protocol TVs (IPTVs), personal computers or other stationary devices, or mobile or handheld devices such as personal digital devices ( PDA), smartphones, tablet PCs or laptops.

[227] As used herein, "wired/wireless network" collectively means communication networks supporting various communication standards or protocols for data exchange and/or interconnection between digital devices or between a digital device and an external server. Such wired/wireless networks may include communication networks currently supported or to be supported in the future, and communication protocols for such communication networks, and may be formed, for example, by communication standards for wired connection, including USB (Universal serial bus), CVBS (Composite Video Sync Bleeding), Component, S-Video (Analog), DVI (Digital Video Interface), HDMI (High Definition Multimedia Interface), RGB or D-SUB, and communication standards for wireless connection including Bluetooth, RFID (Radio Frequency Identification), IrDA (Infrared Data Association standard), UWB (Ultra-Wideband), ZigBee, DLNA (Digital Home Network Alliance), WLAN (Wireless LAN) (Wi- Fi), WiBro (Wireless Broadband Standard), Wimax (Global Interoperability Standard for Broadband Wireless Access), H SDPA (High Speed Downlink Packet Access), LTE (Long Term Evolution) or Wi-Fi Direct.

[228] Hereinafter, when referred to simply as "digital device" in the disclosure, it may mean one or both of a fixed device and/or a mobile device, depending on the context.

[229] Meanwhile, the digital device is an intelligent device that supports, for example, broadcast reception, computer functions, and at least one external input, and can support, for example, e-mail, web browsing, banking , games or applications via the above wired/wireless network. Additionally, the digital device may include an interface to support at least one input or control means (hereinafter, input means) such as a handwriting device, a touch screen, and a spatial remote control. The digital device may use a standardized general purpose operating system (OS). For example, a digital device can add, remove, modify, and update various applications in a general purpose OS kernel, thereby configuring and providing a more user-friendly environment.

[230] The above embodiments consider predetermined combinations of components and disclosure features. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature can be practiced in such a way that it is not combined with other components or features. Additionally, certain components and/or features may be combined with each other to configure an embodiment of the disclosure. The order of operations described in connection with the embodiments of the disclosure may vary. Some components or features of one embodiment may be included in another embodiment, or may be replaced by corresponding components or features of another embodiment. Obviously, claims may be combined to constitute an embodiment, unless expressly stated otherwise, or such combinations may be added to a new claim by post-filing amendment.

[231] When implemented in firmware or hardware, an embodiment of the disclosure may be implemented as a module, procedure, or function that performs the functions or operations described above. The program code may be stored in a storage device and sent by the processor. The memory device may be positioned inside or outside the processor to communicate with the processor through various known means.

[232] Those skilled in the art should appreciate that the disclosure may take other specific forms without departing from the spirit of the disclosure. Thus, the foregoing description is not to be interpreted as limiting in all respects, but as exemplary. The scope of the disclosure is to be determined by reasonable interpretations of the appended claims, and all equivalents of the disclosure are covered by the scope of the disclosure.

Industrial Applicability

[233] The preferred embodiments of the present disclosure are disclosed above for illustrative purposes, and hereinafter, modifications, alterations, substitutions, or additions to various other embodiments are made within the technical spirit and scope of the present disclosure, as defined by the appended claims for those skilled in the art. the field of technology.

Claims (27)

1. A method for processing video data, comprising the steps of: determining whether the first prediction mode is applied to the current block, wherein the first prediction mode refers to another block in the current frame; configuring a list of candidate block vectors of the current block based on applying the first prediction mode to the current block; And generating a predictive sample of the current block based on the block vector included in the list of possible block vectors, wherein, when configuring the block vector candidate list, the block vector candidate list is configured only based on the spatial neighboring block to which the first prediction mode is applied, the historical motion vector prediction (HMVP) candidate to which the first prediction mode is applied, and the null vector by adding the spatial neighbor block vector, the HMVP candidate, and the null vector to the list of block vector candidates in the order of the spatial neighbor block vector, the HMVP candidate, and the null vector, wherein the null vector is added to the list of possible block vectors until the number of current possibilities from the list of possible block vectors becomes the maximum number of possible options. 2. The method of claim 1, wherein the spatial neighbor includes at least one of a left side neighbor, a left bottom neighbor, a top side neighbor, and a right top neighbor. 3. The method of claim 1, wherein the temporal neighbor opportunity and the pairwise opportunity generated based on the combination of block vectors included in the block vector candidate list are not included in the block vector candidate list. 4. A method for encoding video data, comprising the steps of: determining whether to apply the first prediction mode to the current block, the first mode referring to another block in the current frame; configuring a list of candidate block vectors of the current block based on applying the first prediction mode to the current block; generating a predictive sample of the current block based on the block vector included in the list of candidate block vectors; And encode information related to prediction of the current block, wherein, when configuring the block vector candidate list, the block vector candidate list is configured only based on the spatial neighboring block to which the first prediction mode is applied, the history-based motion vector prediction (HMVP) candidate to which the first prediction mode is applied, and the null vector by adding the spatial neighbor block vector, the HMVP candidate, and the null vector to the list of block vector candidates in the order of the spatial neighbor block vector, the HMVP candidate, and the null vector, wherein the null vector is added to the list of possible block vectors until the number of current possibilities from the list of possible block vectors becomes the maximum number of possible options. 5. The method of claim 4, wherein the spatial neighbor includes at least one of a left side neighbor, a left bottom neighbor, a top side neighbor, and a right top neighbor. 6. The method of claim 4, wherein the temporal neighbor opportunity and the pairwise opportunity generated based on the combination of block vectors included in the block vector candidate list are not included in the block vector candidate list. 7. A method for transmitting data containing a bit stream for an image, the method comprising: obtaining a bit stream for the image; And transmission of data containing a stream of bits, wherein the bit stream is generated by performing steps in which: determining whether to apply the first prediction mode to the current block, the first mode referring to another block in the current frame; configuring a block vector list of the current block based on applying the first prediction mode to the current block; generating a predictive sample of the current block based on the block vector included in the list of candidate block vectors; And encode information related to prediction of the current block, wherein, when configuring the block vector candidate list, the block vector candidate list is configured only based on the spatial neighboring block to which the first prediction mode is applied, the history-based motion vector prediction (HMVP) candidate to which the first prediction mode is applied, and the null vector by adding the spatial neighbor block vector, the HMVP candidate, and the null vector to the list of block vector candidates in the order of the spatial neighbor block vector, the HMVP candidate, and the null vector, wherein the null vector is added to the list of possible block vectors until the number of current possibilities from the list of possible block vectors becomes the maximum number of possible options.

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