WO2020004931A1 - Procédé et dispositif pour traiter une image selon un mode d'inter-prédiction dans un système de codage d'image - Google Patents

Procédé et dispositif pour traiter une image selon un mode d'inter-prédiction dans un système de codage d'image Download PDF

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WO2020004931A1
WO2020004931A1 PCT/KR2019/007719 KR2019007719W WO2020004931A1 WO 2020004931 A1 WO2020004931 A1 WO 2020004931A1 KR 2019007719 W KR2019007719 W KR 2019007719W WO 2020004931 A1 WO2020004931 A1 WO 2020004931A1
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candidate
merge
candidate list
current block
prediction
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PCT/KR2019/007719
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English (en)
Korean (ko)
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박내리
남정학
이재호
장형문
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엘지전자 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/44—Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/50—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding
    • H04N19/503—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction
    • H04N19/51—Motion estimation or motion compensation
    • H04N19/513—Processing of motion vectors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/70—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards

Definitions

  • the present invention relates to an image coding technology, and more particularly, to an image processing method and apparatus according to inter prediction in an image coding system.
  • the demand for high resolution and high quality images such as high definition (HD) images and ultra high definition (UHD) images is increasing in various fields.
  • the higher the resolution and the higher quality of the image data the more information or bit rate is transmitted than the existing image data. Therefore, the image data can be transmitted by using a medium such as a conventional wired / wireless broadband line or by using a conventional storage medium. In the case of storage, the transmission cost and the storage cost are increased.
  • a high efficiency image compression technique is required to effectively transmit, store, and reproduce high resolution, high quality image information.
  • An object of the present invention is to provide a method and apparatus for improving image coding efficiency.
  • Another object of the present invention is to provide an image decoding method and apparatus for reducing complexity in a process of refining a motion vector during decoding.
  • an image decoding method performed by a decoding apparatus.
  • the method may include: deriving a merge index of a current block, constructing a merge candidate list of the current block, deriving a specific candidate from the merge candidate list based on whether the merge candidate list is rearranged, and the merge Performing refinement on the specific candidate based on an index, adding the refined candidate to the merge candidate list, and predicting the current block based on the merge candidate list Generating a decoded block.
  • a decoding apparatus for performing image decoding.
  • the decoding apparatus derives an entropy decoding unit for obtaining prediction information on a current block and a merge index of the current block, constructs a merge candidate list of the current block, and merges the merge based on the merge candidate list.
  • Deriving a specific candidate from the candidate list, performing refinement on the specific candidate based on the merge index, adding the specific candidate performing the refinement to the merge candidate list, and the merge candidate list It characterized in that it comprises a prediction unit for generating a predicted block for the current block based on.
  • a video encoding method performed by an encoding apparatus includes constructing a merge candidate list of a current block, deriving a specific candidate from the merge candidate list based on whether the merge candidate list is rearranged, and performing refinement on the specific candidate. Adding a specific candidate that performed the refinement to the merge candidate list, generating a predicted block for the current block based on the merge candidate list, and deriving a merge index of the current block And generating, encoding, and outputting prediction information about the current block.
  • a video encoding apparatus constructs a merge candidate list of the current block, derives a specific candidate from the merge candidate list based on whether the merge candidate list is rearranged, performs refinement on the specific candidate, A prediction unit and a current unit configured to add a specific candidate that has performed the refinement to the merge candidate list, generate a predicted block for the current block based on the merge candidate list, and derive a merge index of the current block; And an entropy encoding unit for generating, encoding, and outputting prediction information about the block.
  • motion information may be derived from a neighboring block, and the derived motion information may be refined to increase accuracy of motion prediction.
  • the complexity of the decoder can be reduced while reordering and refinement can be performed, thereby improving coding efficiency.
  • FIG. 1 is a diagram schematically illustrating a configuration of a video encoding apparatus to which the present invention may be applied.
  • FIG. 2 is a diagram schematically illustrating a configuration of a video decoding apparatus to which the present invention may be applied.
  • FIG 3 schematically illustrates the rearrangement and refinement process of the MVP candidate list.
  • FIG. 4 schematically illustrates a first method of determining whether to apply a refinement process according to a merge index.
  • FIG. 5 schematically illustrates a second method of determining whether to apply a refinement process according to a merge index.
  • FIG. 6 schematically illustrates a third method of determining whether to apply a refinement process according to a merge index.
  • FIG. 8 schematically illustrates an image encoding method by an encoding apparatus according to the present invention.
  • FIG. 9 schematically illustrates an image decoding method by a decoding apparatus according to the present invention.
  • each configuration in the drawings described in the present invention are shown independently for the convenience of description of the different characteristic functions, it does not mean that each configuration is implemented by separate hardware or separate software.
  • two or more of each configuration may be combined to form one configuration, or one configuration may be divided into a plurality of configurations.
  • Embodiments in which each configuration is integrated and / or separated are also included in the scope of the present invention without departing from the spirit of the present invention.
  • the video / picture coding system can include a source device and a receiving device.
  • the source device may deliver the encoded video / image information or data to the receiving device via a digital storage medium or network in the form of a file or streaming.
  • the source device may include a video source, an encoding apparatus, and a transmitter.
  • the receiving device may include a receiving unit, a decoding apparatus, and a renderer.
  • the encoding device may be called a video / image encoding device, and the decoding device may be called a video / image decoding device.
  • the transmitter may be included in the encoding device.
  • the receiver may be included in the decoding device.
  • the renderer may include a display unit, and the display unit may be configured as a separate device or an external component.
  • the video source may acquire the video / image through a process of capturing, synthesizing, or generating the video / image.
  • the video source may comprise a video / image capture device and / or a video / image generation device.
  • the video / image capture device may include, for example, one or more cameras, video / image archives including previously captured video / images, and the like.
  • Video / image generation devices may include, for example, computers, tablets and smartphones, and may (electronically) generate video / images.
  • a virtual video / image may be generated through a computer or the like. In this case, the video / image capturing process may be replaced by a process of generating related data.
  • the encoding device may encode the input video / image.
  • the encoding apparatus may perform a series of procedures such as prediction, transform, and quantization for compression and coding efficiency.
  • the encoded data (encoded video / image information) may be output in the form of a bitstream.
  • the transmitter may transmit the encoded video / video information or data output in the form of a bitstream to the receiver of the receiving device through a digital storage medium or a network in the form of a file or streaming.
  • the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, and the like.
  • the transmission unit may include an element for generating a media file through a predetermined file format, and may include an element for transmission through a broadcast / communication network.
  • the receiver may receive / extract the bitstream and transmit the received bitstream to the decoding apparatus.
  • the decoding apparatus may decode the video / image by performing a series of procedures such as inverse quantization, inverse transformation, and prediction corresponding to the operation of the encoding apparatus.
  • the renderer may render the decoded video / image.
  • the rendered video / image may be displayed through the display unit.
  • the present invention relates to video / picture coding.
  • the methods / embodiments disclosed in the present invention may include a versatile video coding (VVC) standard, an essential video coding (EVC) standard, an AOMedia Video 1 (AV1) standard, a second generation of audio video coding standard (AVS2) or a next generation video / It can be applied to the method disclosed in the image coding standard (eg H.267 or H.268, etc.).
  • VVC versatile video coding
  • EVC essential video coding
  • AV1 AOMedia Video 1
  • AVS2 second generation of audio video coding standard
  • next generation video / It can be applied to the method disclosed in the image coding standard (eg H.267 or H.268, etc.).
  • video may refer to a series of images over time.
  • a picture generally refers to a unit representing one image in a specific time zone, and a slice / tile is a unit constituting part of a picture in coding.
  • the slice / tile may comprise one or more coding tree units (CTUs).
  • CTUs coding tree units
  • One picture may consist of one or more slices / tiles.
  • One picture may consist of one or more tile groups.
  • One tile group may include one or more tiles.
  • the brick may represent a rectangular region of CTU rows within a tile in the picture.
  • tile groups and slices may be used interchangeably.
  • tile group / tile group header may be called slice / slice header.
  • a pixel or a pel may refer to a minimum unit constituting one picture (or image). Also, 'sample' may be used as a term corresponding to a pixel.
  • a sample may generally represent a pixel or a value of a pixel, and may represent only a pixel / pixel value of a luma component or only a pixel / pixel value of a chroma component.
  • a unit may represent a basic unit of image processing.
  • the unit may include at least one of a specific region of the picture and information related to the region.
  • One unit may include one luma block and two chroma (ex. Cb, cr) blocks.
  • the unit may be used interchangeably with terms such as block or area in some cases.
  • an M ⁇ N block may comprise a sample (or sample array) or a set (or array) of transform coefficients of M columns and N rows.
  • FIG. 1 is a diagram schematically illustrating a configuration of a video encoding apparatus to which the present invention may be applied.
  • the encoding apparatus 100 may include an image splitter 110, a subtractor 115, a transformer 120, a quantizer 130, an inverse quantizer 140, an inverse transformer 150,
  • the adder 155, the filter 160, the memory 170, the inter predictor 180, the intra predictor 185, and the entropy encoder 190 may be configured.
  • the inter predictor 180 and the intra predictor 185 may be collectively called a predictor. That is, the predictor may include an inter predictor 180 and an intra predictor 185.
  • the transform unit 120, the quantization unit 130, the inverse quantization unit 140, and the inverse transform unit 150 may be included in the residual processing unit.
  • the residual processing unit may further include a subtracting unit 115.
  • the image divider 110, the subtractor 115, the transformer 120, the quantizer 130, the inverse quantizer 140, the inverse transformer 150, the adder 155, and the filter 160 are described above.
  • the inter predictor 180, the intra predictor 185, and the entropy encoder 190 may be configured by one hardware component (eg, an encoder chipset or a processor) according to an embodiment.
  • the memory 170 may include a decoded picture buffer (DPB) or may be configured by a digital storage medium.
  • the hardware component may further include the memory 170 as an internal / external component.
  • the image divider 110 may divide the input image (or picture or frame) input to the encoding apparatus 100 into one or more processing units.
  • the processing unit may be called a coding unit (CU).
  • the coding unit may be recursively divided according to a quad-tree binary-tree ternary-tree (QTBTTT) structure from a coding tree unit (CTU) or a largest coding unit (LCU).
  • QTBTTT quad-tree binary-tree ternary-tree
  • CTU coding tree unit
  • LCU largest coding unit
  • one coding unit may be divided into a plurality of coding units of a deeper depth based on a quad tree structure, a binary tree structure, and / or a ternary structure.
  • the quad tree structure may be applied first and the binary tree structure and / or ternary structure may be applied later.
  • the binary tree structure may be applied first.
  • the coding procedure according to the present invention may be performed based on the final coding unit that is no longer split.
  • the maximum coding unit may be used as the final coding unit immediately based on coding efficiency according to the image characteristic, or if necessary, the coding unit is recursively divided into coding units of lower depths and optimized.
  • a coding unit of size may be used as the final coding unit.
  • the coding procedure may include a procedure of prediction, transform, and reconstruction, which will be described later.
  • the processing unit may further include a prediction unit (PU) or a transform unit (TU).
  • the prediction unit and the transform unit may be partitioned or partitioned from the aforementioned final coding unit, respectively.
  • the prediction unit may be a unit of sample prediction
  • the transformation unit may be a unit for deriving a transform coefficient and / or a unit for deriving a residual signal from the transform coefficient.
  • an M ⁇ N block may represent a set of samples or transform coefficients composed of M columns and N rows.
  • a sample may generally represent a pixel or a value of a pixel, and may only represent pixel / pixel values of the luma component, or only pixel / pixel values of the chroma component.
  • a sample may be used as a term corresponding to one picture (or image) for a pixel or a pel.
  • the encoding apparatus 100 subtracts the prediction signal (predicted block, prediction sample array) output from the inter prediction unit 180 or the intra prediction unit 185 from the input image signal (original block, original sample array).
  • a signal may be generated (residual signal, residual block, residual sample array), and the generated residual signal is transmitted to the converter 120.
  • a unit that subtracts a prediction signal (prediction block, prediction sample array) from an input image signal (original block, original sample array) in the encoder 100 may be called a subtraction unit 115.
  • the prediction unit may perform a prediction on a block to be processed (hereinafter, referred to as a current block) and generate a predicted block including prediction samples for the current block.
  • the prediction unit may determine whether intra prediction or inter prediction is applied on a current block or CU basis. As described later in the description of each prediction mode, the prediction unit may generate various information related to prediction, such as prediction mode information, and transmit the generated information to the entropy encoding unit 190. The information about the prediction may be encoded in the entropy encoding unit 190 and output in the form of a bitstream.
  • the intra predictor 185 may predict the current block by referring to the samples in the current picture.
  • the referenced samples may be located in the neighborhood of the current block or may be located apart according to the prediction mode.
  • prediction modes may include a plurality of non-directional modes and a plurality of directional modes.
  • Non-directional mode may include, for example, DC mode and planner mode (Planar mode).
  • the directional mode may include, for example, 33 directional prediction modes or 65 directional prediction modes according to the degree of detail of the prediction direction. However, as an example, more or less directional prediction modes may be used depending on the setting.
  • the intra predictor 185 may determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring block.
  • the inter predictor 180 may derive the predicted block with respect to the current block based on the reference block (reference sample array) specified by the motion vector on the reference picture.
  • the motion information may be predicted in units of blocks, subblocks, or samples based on the correlation of the motion information between the neighboring block and the current block.
  • the motion information may include a motion vector and a reference picture index.
  • the motion information may further include inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.) information.
  • the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block present in the reference picture.
  • the reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different.
  • the temporal neighboring block may be referred to as a collocated reference block, a collocated CU (colCU), and the like, and a reference picture including the temporal neighboring block is called a collocated picture (colPic). It may be.
  • the inter prediction unit 180 constructs a motion information candidate list based on neighboring blocks and provides information indicating which candidates are used to derive a motion vector and / or a reference picture index of the current block. Can be generated. Inter prediction may be performed based on various prediction modes.
  • the inter prediction unit 180 may use motion information of a neighboring block as motion information of a current block.
  • the residual signal may not be transmitted.
  • the motion vector of the neighboring block is used as a motion vector predictor and the motion vector difference is signaled by signaling a motion vector difference. Can be directed.
  • the prediction unit may generate a prediction signal based on various prediction methods described below. For example, the prediction unit may not only apply intra prediction or inter prediction to predict one block but also simultaneously apply intra prediction and inter prediction. This may be called combined inter and intra prediction (CIIP).
  • the prediction unit may perform intra block copy (IBC) to predict a block.
  • the intra block copy may be used for content video / video coding of a game or the like, for example, screen content coding (SCC).
  • SCC screen content coding
  • the IBC basically performs prediction in the current picture but may be performed similarly to inter prediction in that a reference block is derived in the current picture. That is, the IBC can use at least one of the inter prediction techniques described in this document.
  • the prediction signal generated by the prediction unit may be used to generate a reconstruction signal or to generate a residual signal.
  • the transformer 120 may apply transform techniques to the residual signal to generate transform coefficients.
  • the transformation technique may be a discrete cosine transform (DCT), a discrete sine transform (DST), a karhunen-lo *? * Ve transform (KLT), a graph-based transform (GBT), or a conditionally non-linear transform (CNT). It may include at least one of.
  • GBT means a conversion obtained from this graph when the relationship information between pixels is represented by a graph.
  • CNT refers to a transform that is generated based on and generates a prediction signal using all previously reconstructed pixels.
  • the conversion process may be applied to pixel blocks having the same size as the square, or may be applied to blocks of variable size rather than square.
  • the quantization unit 130 quantizes the transform coefficients and transmits them to the entropy encoding unit 190.
  • the entropy encoding unit 190 encodes the quantized signal (information about the quantized transform coefficients) and outputs the bitstream. have.
  • the information about the quantized transform coefficients may be referred to as residual information.
  • the quantization unit 130 may rearrange block quantized transform coefficients into a one-dimensional vector form based on a coefficient scan order, and quantize the quantized transform coefficients based on the quantized transform coefficients in the one-dimensional vector form. Information about transform coefficients may be generated.
  • the entropy encoding unit 190 may perform various encoding methods such as, for example, exponential Golomb, context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), and the like.
  • the entropy encoding unit 190 may encode information necessary for video / image reconstruction other than quantized transform coefficients (for example, values of syntax elements) together or separately.
  • Encoded information eg, encoded video / image information
  • NALs network abstraction layer
  • the video / image information may further include information about various parameter sets such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS).
  • the video / image information may further include general constraint information.
  • Signaling / transmitted information and / or syntax elements described later in this document may be encoded and included in the bitstream through the above-described encoding procedure.
  • the bitstream may be transmitted over a network or may be stored in a digital storage medium.
  • the network may include a broadcasting network and / or a communication network
  • the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, SSD, and the like.
  • the signal output from the entropy encoding unit 190 may include a transmitting unit (not shown) for transmitting and / or a storing unit (not shown) for storing as an internal / external element of the encoding apparatus 100, or the transmitting unit It may be included in the entropy encoding unit 190.
  • the quantized transform coefficients output from the quantization unit 130 may be used to generate a prediction signal.
  • the inverse quantization and inverse transform may be applied to the quantized transform coefficients through the inverse quantization unit 140 and the inverse transform unit 150 to restore the residual signal (residual block or residual samples).
  • the adder 155 adds the reconstructed residual signal to the predicted signal output from the inter predictor 180 or the intra predictor 185 so that a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array) is added. Can be generated. If there is no residual for the block to be processed, such as when the skip mode is applied, the predicted block may be used as the reconstructed block.
  • the adder 155 may be called a restoration unit or a restoration block generation unit.
  • the generated reconstruction signal may be used for intra prediction of a next processing target block in a current picture, and may be used for inter prediction of a next picture through filtering as described below.
  • LMCS luma mapping with chroma scaling
  • the filtering unit 160 may improve subjective / objective image quality by applying filtering to the reconstruction signal.
  • the filtering unit 160 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and the modified reconstructed picture is stored in the memory 170, specifically, the DPB of the memory 170.
  • the various filtering methods may include, for example, deblocking filtering, a sample adaptive offset, an adaptive loop filter, a bilateral filter, and the like.
  • the filtering unit 160 may generate various information about the filtering and transmit the generated information to the entropy encoding unit 190.
  • the filtering information may be encoded in the entropy encoding unit 190 and output in the form of a bitstream.
  • the modified reconstructed picture transmitted to the memory 170 may be used as the reference picture in the inter predictor 180.
  • the encoding apparatus may avoid prediction mismatch between the encoding apparatus 100 and the decoding apparatus, and may improve encoding efficiency.
  • the memory 170 DPB may store the modified reconstructed picture for use as a reference picture in the inter predictor 180.
  • the memory 170 may store the motion information of the block from which the motion information in the current picture is derived (or encoded) and / or the motion information of the blocks in the picture that have already been reconstructed.
  • the stored motion information may be transmitted to the inter predictor 180 to use the motion information of the spatial neighboring block or the motion information of the temporal neighboring block.
  • the memory 170 may store reconstructed samples of reconstructed blocks in the current picture, and transfer the reconstructed samples to the intra predictor 185.
  • FIG. 2 is a diagram schematically illustrating a configuration of a video decoding apparatus to which the present invention may be applied.
  • the decoding apparatus 200 includes an entropy decoding unit 210, an inverse quantizer 220, an inverse transform unit 230, an adder 235, a filter 240, a memory 250, and an inter
  • the prediction unit 260 and the intra prediction unit 265 may be configured.
  • the inter predictor 260 and the intra predictor 265 may be collectively called a predictor. That is, the predictor may include an inter predictor 180 and an intra predictor 185.
  • the inverse quantization unit 220 and the inverse transform unit 230 may be collectively called a residual processing unit. That is, the residual processing unit may include an inverse quantization unit 220 and an inverse transformation unit 230.
  • the entropy decoder 210, the inverse quantizer 220, the inverse transformer 230, the adder 235, the filter 240, the inter predictor 260, and the intra predictor 265 are described in the embodiment. It may be configured by one hardware component (for example, decoder chipset or processor).
  • the memory 250 may include a decoded picture buffer (DPB) or may be configured by a digital storage medium.
  • the hardware component may further include the memory 250 as an internal / external component.
  • the decoding apparatus 200 may reconstruct an image corresponding to a process in which video / image information is processed in the encoding apparatus of FIG. 1.
  • the decoding apparatus 200 may derive units / blocks based on block division related information obtained from the bitstream.
  • the decoding apparatus 200 may perform decoding using a processing unit applied in the encoding apparatus.
  • the processing unit of decoding may be a coding unit, for example, and the coding unit may be divided along the quad tree structure, binary tree structure and / or ternary tree structure from the coding tree unit or the largest coding unit.
  • One or more transform units may be derived from the coding unit.
  • the reconstructed video signal decoded and output through the decoding apparatus 200 may be reproduced through the reproducing apparatus.
  • the decoding apparatus 200 may receive a signal output from the encoding apparatus of FIG. 1 in the form of a bitstream, and the received signal may be decoded through the entropy decoding unit 210.
  • the entropy decoding unit 210 may parse the bitstream to derive information (eg, video / image information) necessary for image reconstruction (or picture reconstruction).
  • the video / image information may further include information about various parameter sets such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS).
  • the video / image information may further include general constraint information.
  • the decoding apparatus may further decode the picture based on the information about the parameter set and / or the general restriction information.
  • Signaling / received information and / or syntax elements described later in this document may be decoded through the decoding procedure and obtained from the bitstream.
  • the entropy decoding unit 210 decodes information in a bitstream based on a coding method such as exponential Golomb coding, CAVLC, or CABAC, quantized values of syntax elements required for image reconstruction, and transform coefficients for residuals. Can be output. More specifically, the CABAC entropy decoding method receives a bin corresponding to each syntax element in a bitstream, and decodes syntax element information and decoding information of neighboring and decoding target blocks or information of symbols / bins decoded in a previous step.
  • the context model may be determined using the context model, the probability of occurrence of a bin may be predicted according to the determined context model, and arithmetic decoding of the bin may be performed to generate a symbol corresponding to the value of each syntax element. have.
  • the CABAC entropy decoding method may update the context model by using the information of the decoded symbol / bin for the context model of the next symbol / bean after determining the context model.
  • the information related to the prediction among the information decoded by the entropy decoding unit 210 is provided to a predictor (the inter predictor 260 and the intra predictor 265), and the entropy decoding performed by the entropy decoder 210 is performed.
  • Dual values that is, quantized transform coefficients and related parameter information, may be input to the inverse quantizer 220.
  • information on filtering among information decoded by the entropy decoding unit 210 may be provided to the filtering unit 240.
  • a receiver (not shown) that receives a signal output from the encoding apparatus may be further configured as an internal / external element of the decoding apparatus 200, or the receiver may be a component of the entropy decoding unit 210.
  • the decoding apparatus may be referred to as a video / image / picture decoding apparatus, and the decoding apparatus may be divided into an information decoder (video / image / picture information decoder) and a sample decoder (video / image / picture sample decoder). It may be.
  • the information decoder may include the entropy decoding unit 210, and the sample decoder may include the inverse quantization unit 220, an inverse transformer 230, an adder 235, a filter 240, and a memory 250. ),
  • the inverse quantization unit 220 may dequantize the quantized transform coefficients and output the transform coefficients.
  • the inverse quantization unit 220 may rearrange the quantized transform coefficients in the form of a two-dimensional block. In this case, the reordering may be performed based on the coefficient scan order performed by the encoding apparatus.
  • the inverse quantization unit 220 may perform inverse quantization on quantized transform coefficients using a quantization parameter (for example, quantization step size information), and may obtain transform coefficients.
  • a quantization parameter for example, quantization step size information
  • the inverse transformer 230 inversely transforms the transform coefficients to obtain a residual signal (residual block, residual sample array).
  • the prediction unit may perform prediction on the current block and generate a predicted block including prediction samples for the current block.
  • the prediction unit may determine whether intra prediction or inter prediction is applied to the current block based on the information about the prediction output from the entropy decoding unit 210, and may determine a specific intra / inter prediction mode.
  • the prediction unit may generate a prediction signal based on various prediction methods described below. For example, the prediction unit may not only apply intra prediction or inter prediction to predict one block but also simultaneously apply intra prediction and inter prediction. This may be called combined inter and intra prediction (CIIP).
  • the prediction unit may perform intra block copy (IBC) to predict a block.
  • the intra block copy may be used for content video / video coding of a game or the like, for example, screen content coding (SCC).
  • SCC screen content coding
  • the IBC basically performs prediction in the current picture but may be performed similarly to inter prediction in that a reference block is derived in the current picture. That is, the IBC can use at least one of the inter prediction techniques described in this document.
  • the intra predictor 265 may predict the current block by referring to samples in the current picture.
  • the referenced samples may be located in the neighborhood of the current block or may be located apart according to the prediction mode.
  • prediction modes may include a plurality of non-directional modes and a plurality of directional modes.
  • the intra predictor 265 may determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring block.
  • the inter prediction unit 260 may derive the predicted block for the current block based on the reference block (reference sample array) specified by the motion vector on the reference picture.
  • the motion information may be predicted in units of blocks, subblocks, or samples based on the correlation of the motion information between the neighboring block and the current block.
  • the motion information may include a motion vector and a reference picture index.
  • the motion information may further include inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.) information.
  • the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block present in the reference picture.
  • the inter prediction unit 260 may construct a motion information candidate list based on neighboring blocks and derive a motion vector and / or a reference picture index of the current block based on the received candidate selection information. Inter prediction may be performed based on various prediction modes, and the information about the prediction may include information indicating a mode of inter prediction for the current block.
  • the adder 235 reconstructs the obtained residual signal by adding the obtained residual signal to a predictive signal (predicted block, predictive sample array) output from the predictor (including the inter predictor 260 and / or the intra predictor 265).
  • a signal (restored picture, reconstructed block, reconstructed sample array) can be generated. If there is no residual for the block to be processed, such as when the skip mode is applied, the predicted block may be used as the reconstructed block.
  • the adder 235 may be called a restoration unit or a restoration block generation unit.
  • the generated reconstruction signal may be used for intra prediction of the next block to be processed in the current picture, may be output through filtering as described below, or may be used for inter prediction of the next picture.
  • LMCS luma mapping with chroma scaling
  • the filtering unit 240 may improve subjective / objective image quality by applying filtering to the reconstruction signal.
  • the filtering unit 240 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and the modified reconstructed picture may be stored in the memory 250, specifically, the DPB of the memory 250. Can be sent to.
  • the various filtering methods may include, for example, deblocking filtering, a sample adaptive offset, an adaptive loop filter, a bilateral filter, and the like.
  • the (modified) reconstructed picture stored in the DPB of the memory 250 may be used as the reference picture in the inter predictor 260.
  • the memory 250 may store the motion information of the block from which the motion information in the current picture is derived (or decoded) and / or the motion information of the blocks in the picture that have already been reconstructed.
  • the stored motion information may be transmitted to the inter predictor 260 to use the motion information of the spatial neighboring block or the motion information of the temporal neighboring block.
  • the memory 250 may store reconstructed samples of reconstructed blocks in the current picture, and transfer the reconstructed samples to the intra predictor 265.
  • the embodiments described by the filtering unit 160, the inter prediction unit 180, and the intra prediction unit 185 of the encoding apparatus 100 are respectively the filtering unit 240 and the inter prediction of the decoding apparatus 200. The same may also apply to the unit 260 and the intra predictor 265.
  • the prediction unit of the encoding apparatus / decoding apparatus may derive the prediction sample by performing inter prediction on a block basis.
  • Inter prediction may represent prediction derived in a manner dependent on data elements (e.g. sample values, motion information, etc.) of the picture (s) other than the current picture.
  • data elements e.g. sample values, motion information, etc.
  • a predicted block (prediction sample array) for the current block is derived based on a reference block (reference sample array) specified by a motion vector on the reference picture indicated by the reference picture index.
  • the motion information of the current block may be predicted in units of blocks, subblocks, or samples based on the correlation of the motion information between the neighboring block and the current block.
  • the motion information may include a motion vector and a reference picture index.
  • the motion information may further include inter prediction type (L0 prediction, L1 prediction, Bi prediction, etc.) information.
  • the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block present in the reference picture.
  • the reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different.
  • the temporal neighboring block may be referred to as a collocated reference block, a collocated CU (colCU), and the like, and a reference picture including the temporal neighboring block is called a collocated picture (colPic). It may be.
  • a motion information candidate list may be constructed based on neighboring blocks of the current block, and a flag indicating which candidate is selected (used) to derive a motion vector and / or a reference picture index of the current block. Or index information may be signaled.
  • Inter prediction may be performed based on various prediction modes. For example, in the case of the skip mode and the merge mode, the motion information of the current block may be the same as the motion information of the selected neighboring block. In the skip mode, unlike the merge mode, the residual signal may not be transmitted.
  • a motion vector prediction (MVP) mode a motion vector of a selected neighboring block is used as a motion vector predictor, and a motion vector difference may be signaled. In this case, the motion vector of the current block may be derived using the sum of the motion vector predictor and the motion vector difference.
  • MVP motion vector prediction
  • the motion information may include L0 motion information and / or L1 motion information according to an inter prediction type (L0 prediction, L1 prediction, Bi prediction, etc.).
  • the motion vector in the L0 direction may be referred to as an L0 motion vector or MVL0
  • the motion vector in the L1 direction may be referred to as an L1 motion vector or MVL1.
  • the prediction based on the L0 motion vector may be called L0 prediction
  • the prediction based on the L1 motion vector may be called L1 prediction
  • the prediction based on both the L0 motion vector and the L1 motion vector may be called pair (Bi) prediction. Can be.
  • the L0 motion vector may indicate a motion vector associated with the reference picture list L0 (L0), and the L1 motion vector may indicate a motion vector associated with the reference picture list L1 (L1).
  • the reference picture list L0 may include pictures that are earlier in the output order than the current picture as reference pictures, and the reference picture list L1 may include pictures that are later in the output order than the current picture.
  • the previous pictures may be called forward (reference) pictures, and the subsequent pictures may be called reverse (reference) pictures.
  • the reference picture list L0 may further include pictures that are later in the output order than the current picture as reference pictures. In this case, the previous pictures may be indexed first in the reference picture list L0 and the subsequent pictures may be indexed next.
  • the reference picture list L1 may further include previous pictures as reference pictures in output order than the current picture.
  • the subsequent pictures may be indexed first in the reference picture list 1 and the previous pictures may be indexed next.
  • the output order may correspond to a picture order count (POC) order.
  • POC picture order count
  • Inter prediction may be performed using motion information of the current block.
  • the encoding apparatus may derive optimal motion information for the current block through a motion estimation procedure. For example, the encoding apparatus may search for a similar reference block having a high correlation using the original block in the original picture for the current block in fractional pixel units within a predetermined search range in the reference picture, thereby deriving motion information. Can be. Similarity of blocks can be derived based on the difference of phase based sample values. For example, the similarity of the blocks may be calculated based on the SAD between the current block (or template of the current block) and the reference block (or template of the reference block). In this case, motion information may be derived based on a reference block having the smallest SAD in the search area. The derived motion information may be signaled to the decoding apparatus according to various methods based on the inter prediction mode.
  • An embodiment of the present invention relates to inter prediction, and may propose a method for reducing complexity when refinement of a motion vector in a decoding process.
  • an embodiment of the present invention provides a method for reordering and refining a motion vector list, a method for improving complexity in a process of refining a motion vector, a method for improving complexity in a process for realigning and refining a motion vector, and a map in a motion vector list.
  • the process of predicting motion information in inter prediction may be essentially applied to reduce motion information and residual signals.
  • a merge mode in which motion information is derived from neighboring blocks to save information on a motion vector and a reference block is an example of the process, and the accuracy of motion prediction can be improved by refining motion information derived from limited information.
  • DMVD decoder-side motion derivation
  • an embodiment of the present invention can propose a method for reducing the complexity in the rearrangement and refinement process used in the DMVD process.
  • FIG 3 schematically illustrates the rearrangement and refinement process of the MVP candidate list.
  • an embodiment may configure an MVP candidate list in the AMVP mode (S300) and may rearrange the candidate list (S310).
  • a template matching method may be used for reordering candidate lists.
  • refinement may be performed on a specific candidate from the rearranged candidate list (S320). In one embodiment, this can find a motion vector with high motion accuracy.
  • an embodiment may determine whether to update a specific candidate from a candidate list based on the result of refinement for a specific candidate (S330), and when updating, select a specific candidate as an MVP candidate list based on the result of refinement. It may be added to (S340), and it is possible to perform a duplicate check whether there are no candidates in the MVP candidate list (S350).
  • an embodiment may perform a duplicate check to see if there are no duplicate candidates in the MVP candidate list immediately (S350).
  • the duplicate check may be referred to as a pruning check.
  • a zero vector, a modified candidate and / or other various candidates described later with reference to FIG. 7 may be further added (S360), and finally, the MVP candidates The list may be updated (S370).
  • steps S360 and S370 may be omitted.
  • the maximum number of candidates in the MVP candidate list may be omitted.
  • the candidate list may be rearranged, and refinement may be performed on a specific candidate of the candidate list. Subsequently, a duplicate check may be performed to determine whether the same motion information exists on the candidate list based on the refinement result of the specific candidate. If not, the candidate list may be updated.
  • the template matching method may also be used to perform refinement (S320), and although not illustrated in FIG. 3, refinement may be performed depending on whether or not the candidate list rearrangement stage (S310) exists or does not exist. Target candidates of the mention may be determined.
  • a candidate having a smallest template matching cost among the rearranged candidates may be determined as a candidate for refinement.
  • the cost may be generally determined based on a sum of absolute difference (SAD) value. That is, the SAD value can be used.
  • SAD value can be used.
  • pixel values of the neighboring block of the current block and the neighboring block of the reference block indicated by the candidate motion vector may be used.
  • the adjacent block may refer to a block in the template or template region. That is, the SAD value may be calculated based on the pixel values of the block in the template area of the reference block indicated by the block and the candidate motion vector in the template area of the current block.
  • the candidate located first after constructing the MVP candidate list may be determined as the candidate to be refined.
  • a candidate for storing an MVP in sub-block units exists in the candidate list, and when the candidate is determined as a target candidate, the neighboring block of the current block and the reference block indicated by the motion vector of each sub-block
  • the cost may be calculated for neighboring blocks, resulting in inaccurate motion vectors.
  • an adjacent area of each subblock in the current block may not be reconstructed.
  • One embodiment may not perform the refinement process to prevent the induction of the inaccurate motion vector described above, or may determine a candidate candidate located next to the next among the rearranged candidates as a target candidate. That is, when the candidate list reordering step is performed, the candidate having the second smallest template matching cost value may be determined as a candidate for refining. In addition, when the candidate list reordering step is not performed, a candidate located next to the MVP candidate list may be determined as a candidate for refinement.
  • a candidate list may be configured. That is, the candidate list may refer to a motion information candidate list, and the aforementioned candidate list may represent a merge candidate list or an MVP candidate list.
  • the merge mode will be described as an example in FIGS. 4 to 7, but the AMVP mode may be applied in the same manner.
  • FIG. 4 schematically illustrates a first method of determining whether to apply a refinement process according to a merge index.
  • MVP accuracy may be increased through refinement, but the process of calculating a template matching cost for an adjacent block of the current block may affect an increase in decoder complexity. have. Therefore, hereinafter, a method for reducing the influence of the decoder complexity increase may be proposed.
  • whether to apply refinement may be determined based on a merge index obtained through a parsing process.
  • the MERGE_INDEX may be an index for indicating a candidate selected in the merge candidate list. As the MERGE_INDEX value is smaller, the encoding information is reduced, and thus compression efficiency may be improved. Therefore, the merge candidate may occur most frequently when MERGE_INDEX is 0, and it may be considered that the merge candidate has the highest accuracy. Accordingly, one embodiment may perform refinement only when MERGE_INDEX is 0, and may not perform refinement when it is larger than zero.
  • an embodiment may acquire MERGE_INDEX (S400) and construct a merge candidate list (S410).
  • one embodiment may determine whether the MERGE_INDEX value is 0 (S420), and if it is 0, refinement may be performed on the target candidate (S430). Thereafter, it may be determined whether to update based on the result of refinement (S440), and when updating, it may be added to the candidate list (S450). However, if the MERGE_INDEX value is not 0 and no update is made, the relevant step can be immediately terminated.
  • refinement may be performed on candidates having relatively high accuracy, the accuracy of candidates having refined may be further increased, and the complexity of the decoder may be reduced at the same time by reducing the number of refinements. .
  • FIG. 5 schematically illustrates a second method of determining whether to apply a refinement process according to a merge index.
  • the target candidate for refinement may be determined as a motion vector located first in the construction order after merging candidate list construction. In this case, when the first candidate is a subblock, refinement may not be performed, and a next motion vector may not be considered for refinement.
  • the refined candidate may be stored in the candidate list in place of the target candidate.
  • the target candidate may be replaced with a refined candidate, and the refined candidate may be added to the candidate list.
  • an embodiment may acquire MERGE_INDEX (S500) and construct a merge candidate list (S510).
  • one embodiment may determine whether the MERGE_INDEX value is 0 (S520), and if it is 0, it may be determined whether the target candidate is not a subblock type (S530).
  • refinement may be performed on the target candidate (S540), it may be determined whether to update based on the result of the refinement (S550), and when updating, the candidate list Can be added to (S560).
  • the relevant step may be immediately terminated if the target candidate is a subblock type and if the update is not performed.
  • FIG. 6 schematically illustrates a third method of determining whether to apply a refinement process according to a merge index.
  • One embodiment may propose the following method for reducing decoder complexity, as described above. That is, after rearranging the candidate list, a method applicable to the refinement may be proposed.
  • the candidate with the smallest template matching cost may be refined.
  • whether to apply refinement may be determined based on the merge index obtained through the parsing process. For example, refinement may be performed only when MERGE_INDEX is 0, and refinement may not be performed when greater than zero. In this case, the number of refinements is reduced, so that the complexity of the decoder may be simultaneously reduced.
  • the refined candidate may be stored in the candidate list in place of the target candidate as described above. Alternatively, the target candidate may be replaced with a refined candidate, and the refined candidate may be added to the candidate list.
  • an embodiment may obtain MERGE_INDEX (S600), construct a merge candidate list (S610), and rearrange the candidate list (S620).
  • one embodiment may determine whether the MERGE_INDEX value is 0 (S630), if 0, refinement may be performed on the target candidate (S640), and it may be determined whether to update based on the result of the refinement. If updated (S650), it can be added to the candidate list (S660). Thereafter, an embodiment may perform a duplicate check process (S670), a candidate addition process (S680), and a candidate list update process (S690).
  • a duplicate check process (S670), a candidate addition process (S680), and a candidate list update process (S690) may be performed immediately.
  • the candidate adding process (S680) may mean a process of adding a zero vector, a modified candidate and / or various other candidates described later with reference to FIG. 7.
  • the candidate list updating process S690 may mean a process of finally updating the candidate list after further adding candidates, but steps S680 and S690 may be omitted. Alternatively, the maximum number of candidates in the candidate list may be omitted.
  • the tradeoff relationship between performance and complexity may be changed and applied as follows.
  • a new candidate may be added to use various motion information as a candidate, and the following candidate may be considered.
  • a modified candidate based on the refined candidate may be added.
  • the modified candidate MV may be calculated as the sum of RefinedMV and DeltaMV as shown in Equation 1.
  • DeltaMV may indicate a position of +1 or -1 in units of integer pels based on the RefinedMV, and may be scaled.
  • RefinedMV may be referred to as refined motion vector
  • DeltaMV may be referred to as delta motion vector.
  • the L0 and L1 pairs may be configured in opposite directions of the respective X and Y coordinates as shown in Table 1. To this end, it may be possible to determine the L0 and L1 pair by whether True-Bi.
  • True-Bi may refer to a case in which reference pictures of L0 and L1 are in opposite directions with respect to the current picture.
  • the scale value may be changed as shown in FIG. 7.
  • the deformation of the integral fel unit is referred to as STEP 1
  • the deformation of the 2 * integral pel unit may be referred to as STEP 2.
  • STEP 1 to N deformation of a sub-pel unit, or deformation of a quarter-pel unit may be possible.
  • the subpel may mean 1/2 pel.
  • a diamond-shaped deformation may be included, but a deformation into any shape may be possible. Or may be included.
  • the above-described method may be an example of applying DeltaMV based on refinement, but may also apply DeltaMV to a candidate that is not a refined candidate. This is because, when applying refinement only in limited conditions to reduce the complexity of the decoder, applying DeltaMV based on the refined candidate may cause mismatch between encoders / decoders.
  • the process of refining the target candidate may be applied within a predetermined search range.
  • a predetermined search range since there is a high probability that the difference between the first candidate or the motion information with the first candidate MVP overlaps with a small candidate or a candidate with a lower accuracy, such a candidate may be eliminated in the duplicate check process to add a new candidate. have.
  • the merge mode is described as an example, but a candidate list may be configured even when the AMVP mode is applied to the current block. That is, the candidate list may refer to a motion information candidate list, and the aforementioned candidate list may represent a merge candidate list or an MVP candidate list.
  • FIG. 8 schematically illustrates an image encoding method by an encoding apparatus according to the present invention.
  • the method disclosed in FIG. 8 may be performed by the encoding apparatus disclosed in FIG. 1. Specifically, for example, S800 to S850 of FIG. 8 may be performed by the prediction unit of the encoding apparatus, and S860 may be performed by the entropy encoding unit of the encoding apparatus.
  • a process of deriving a residual sample for the current block based on the original sample and the prediction sample for the current block may be performed by a subtractor of the encoding apparatus,
  • the generating of the information about the residual on the basis of the current block may be performed by a converter of the encoding apparatus.
  • the encoding of the information on the residual and the prediction of the current block may be performed. It may be performed by the entropy encoding unit of the encoding device.
  • the encoding apparatus constructs a merge candidate list of the current block (S800).
  • the encoding apparatus may derive neighboring blocks for the motion information candidate list of the current block among neighboring blocks of the current block.
  • the prediction mode of the current block may be determined. For example, the encoding apparatus may apply inter prediction to the current block.
  • the encoding apparatus may select neighboring blocks for the motion information candidate list of the current block among the neighboring blocks of the current block.
  • the encoding apparatus may construct the motion information candidate list based on the derived or selected neighboring blocks.
  • the encoding apparatus may derive motion information of the selected neighboring blocks as motion information candidates of the current block, and construct the motion information candidate list including the motion information candidates.
  • the encoding apparatus may derive the motion information derived by combining the motion information of the selected neighboring blocks as the motion information candidate of the current block, and configure the motion information candidate list including the motion information candidate.
  • the motion information candidate list may indicate a merge candidate list as the current block is a merge mode, but an MVP candidate list may be used when the current block is an AMVP mode.
  • the encoding apparatus derives a specific candidate from the merge candidate list based on whether the merge candidate list is rearranged (S810). That is, a specific candidate derived from the merge candidate list may vary depending on whether or not the merge candidate list is rearranged. However, it is not necessarily different and may be derived in the same way.
  • the template matching method may be used to rearrange the merge candidate list.
  • the specific candidate derived may be a target candidate for refinement.
  • the specific candidate may include a candidate having a smallest template matching cost among the merge candidate lists.
  • the template matching cost may be determined based on a sum of absolute difference (SAD) value, and pixel values of the neighboring block of the current block and the neighboring block of the reference block indicated by the candidate motion vector may be used for the SAD calculation.
  • the adjacent block may refer to a block in the template or template region.
  • the template matching cost has two template matching costs.
  • the second smallest candidate may be included. This is because an incorrect motion vector may be derived when a cost or template matching cost is calculated for the neighboring block of the current block and the neighboring block of the reference block indicated by the motion vector of each subblock. Or, for example, when the candidate having the smallest template matching cost is a subblock unit, the refinement process may not be performed.
  • the specific candidate may include a candidate located first of the merge candidate list. That is, when the reordering does not change the order among the candidates in the merge candidate list, since the first candidate in the merge candidate list may have the highest accuracy in prediction, the first candidate is selected as the target candidate of the refinement. Can be determined.
  • the specific candidate may include the second candidate of the merge candidate list. This is because an incorrect motion vector may be derived when the candidate is in subblock units as described above. A more detailed description has been given above with reference to FIG. 3.
  • the encoding apparatus performs refinement on the specific candidate (S820). That is, the specific candidate may be a candidate for refinement, and in this regard, the decoding apparatus may determine whether refinement is performed based on a merge index or a MERGE_INDEX.
  • refinement may be performed on the specific candidate only when the merge index is zero.
  • the specific candidate may be referred to as a merge candidate or may be a candidate indicating when the merge index is zero. Since the merge candidate having the merge index of 0 has the highest prediction accuracy among the candidates in the candidate list, refinement is performed only on these candidates, and refinement may be performed to expect higher accuracy. In addition, the number of refinements is also reduced, so that the complexity of the decoder can be simultaneously reduced.
  • refinement when the above-described candidate is a subblock unit, refinement may not be performed, and for this, it may be determined whether the above-described candidate is a subblock unit. In addition, when the above-described candidate is a subblock unit, refinement may be performed on the next-order candidate, and the refinement may not be performed on the next-order candidate.
  • refinement may be performed on the specific candidate only when the merge index is less than or equal to a specific value. This is because if the refinement is applied only when the merge index is 0, the complexity of the decoder is reduced, but the compression efficiency may decrease as the target of the refinement decreases.
  • the specific value may be represented by N, and N may have a value ranging from 0 to the maximum number of merge candidates in consideration of complexity. For example, when N is 1, refinement may be performed on up to two candidates.
  • the encoding apparatus adds the specific candidate that performed the refinement to the merge candidate list (S830).
  • the refined candidate may be stored in the candidate list in place of a specific candidate or target candidate. That is, the target candidate may be replaced with a refined candidate. Alternatively, the refined candidate may be added to the candidate list.
  • the merge candidate list may add modified candidates.
  • the modified candidate may include candidates scaled by integer pels based on a motion vector of a specific candidate.
  • the modified candidate can be calculated based on RefinedMV and DeltaMV.
  • RefinedMV may be referred to as a motion vector or refined motion vector of a candidate on which refinement is performed
  • DeltaMV may be referred to as a delta motion vector.
  • DeltaMV may indicate a position of +1 or -1 in integer pel units based on RefinedMV and may be scaled.
  • it is not limited to the purified water pel, sub-pel or quarter-pel unit may be used. A more detailed description has been given above with reference to FIG. 7.
  • the encoding apparatus generates a predicted block for the current block based on the merge candidate list (S840). That is, the prediction of the current block may be performed based on the motion information.
  • a predicted block of the current block may be derived based on the motion information, and a reconstructed block may be derived based on the predicted block.
  • the encoding apparatus may derive a reference block within a reference picture based on the motion information.
  • the motion information may include a motion vector and a reference picture index.
  • the encoding apparatus may derive the reference picture indicated by the reference picture index among the reference pictures of the reference picture list as the reference picture of the current block, and convert the block indicated by the motion vector in the reference picture into the reference block of the current block. Can be derived.
  • the encoding apparatus may generate a prediction sample based on the reference block.
  • the encoding apparatus may generate a residual sample based on the original sample and the generated prediction sample.
  • the encoding apparatus may generate information about the residual based on the residual sample.
  • the information about the residual may include transform coefficients related to the residual sample.
  • the encoding apparatus may derive the reconstructed sample based on the prediction sample and the residual sample. That is, the encoding apparatus may derive the reconstructed sample by adding the prediction sample and the residual sample.
  • the encoding apparatus may generate a residual block based on the original block and the predicted block, and may generate information about the residual based on this.
  • the encoding apparatus may encode the information about the residual and output the bitstream.
  • the bitstream may be transmitted to a decoding apparatus via a network or a storage medium.
  • the encoding apparatus derives the merge index of the current block (S850).
  • the encoding apparatus may select a specific motion information candidate from the motion information candidates of the motion information candidate list, and derive the selected motion information candidate as motion information for the current block.
  • the encoding apparatus may generate and encode index information indicating the selected motion information candidate among the motion information candidates of the motion information candidate list. Meanwhile, the index information may indicate a merge index, and the merge index may indicate MERGE_INDEX.
  • the encoding apparatus may derive a merge index indicating a candidate used to generate the predicted block of the current block among the merge candidate list.
  • the encoding apparatus generates, encodes, and outputs prediction information about the current block (S860).
  • the encoding apparatus may encode and output the video information including the information on the prediction of the current block in the form of a bitstream.
  • the encoding apparatus may determine the prediction mode of the current block, and generate information indicating the prediction mode.
  • information on the merge candidate list structure of the current block and information on the merge index may be generated.
  • reordering related information and / or refinement related information about the current block may be generated.
  • information about the residual may be generated.
  • the above-described information about prediction of the current block may include all of the above-described information or may include only a part of the information.
  • the bitstream may be transmitted to a decoding apparatus via a network or a storage medium.
  • FIG. 9 schematically illustrates an image decoding method by a decoding apparatus according to the present invention.
  • the method disclosed in FIG. 9 may be performed by the decoding apparatus disclosed in FIG. 2. Specifically, for example, S900 to S950 of FIG. 9 may be performed by the prediction unit of the decoding apparatus.
  • a process of acquiring image information including information on prediction of a current block and information on residual through a bitstream may be performed by an entropy decoding unit of the decoding apparatus.
  • the process of deriving the residual sample for the current block based on the dual information may be performed by an inverse transform unit of the decoding apparatus, and the process of generating a reconstructed picture based on the prediction sample and the residual sample may be performed. It may be performed by an adder of the decoding apparatus.
  • the decoding apparatus derives the merge index of the current block (S900).
  • the decoding apparatus may select a specific motion information candidate from among motion information candidates of the motion information candidate list based on a merge index, and derive the selected motion information candidate as motion information for the current block.
  • the merge index may indicate index information and may indicate MERGE_INDEX.
  • the decoding apparatus configures a merge candidate list of the current block (S910).
  • the decoding apparatus may derive neighboring blocks for the motion information candidate list of the current block among neighboring blocks of the current block.
  • the prediction mode of the current block may be determined. For example, the decoding apparatus may apply inter prediction to the current block.
  • the decoding apparatus may select neighboring blocks for the motion information candidate list of the current block among the neighboring blocks of the current block.
  • the decoding apparatus may construct the motion information candidate list based on the derived or selected neighboring blocks.
  • the decoding apparatus may derive the motion information of the selected neighboring blocks as motion information candidates of the current block, and construct the motion information candidate list including the motion information candidates.
  • the decoding apparatus may derive the motion information derived by combining the motion information of the selected neighboring blocks as the motion information candidate of the current block, and configure the motion information candidate list including the motion information candidate.
  • the motion information candidate list may indicate a merge candidate list as the current block is a merge mode, but an MVP candidate list may be used when the current block is an AMVP mode.
  • the decoding apparatus derives a specific candidate from the merge candidate list based on whether the merge candidate list is rearranged (S920). That is, a specific candidate derived from the merge candidate list may vary depending on whether or not the merge candidate list is rearranged. However, it is not necessarily different and may be derived in the same way.
  • the template matching method may be used to rearrange the merge candidate list.
  • the specific candidate derived may be a target candidate for refinement.
  • the specific candidate may include a candidate having a smallest template matching cost among the merge candidate lists.
  • the template matching cost may be determined based on a sum of absolute difference (SAD) value, and pixel values of the neighboring block of the current block and the neighboring block of the reference block indicated by the candidate motion vector may be used for the SAD calculation.
  • the adjacent block may refer to a block in the template or template region.
  • the template matching cost has two template matching costs.
  • the second smallest candidate may be included. This is because an incorrect motion vector may be derived when a cost or template matching cost is calculated for the neighboring block of the current block and the neighboring block of the reference block indicated by the motion vector of each subblock. Or, for example, when the candidate having the smallest template matching cost is a subblock unit, the refinement process may not be performed.
  • the specific candidate may include a candidate located first of the merge candidate list. That is, when the reordering does not change the order among the candidates in the merge candidate list, since the first candidate in the merge candidate list may have the highest accuracy in prediction, the first candidate is selected as the target candidate of the refinement. Can be determined.
  • the specific candidate may include the second candidate of the merge candidate list. This is because an incorrect motion vector may be derived when the candidate is in subblock units as described above. A more detailed description has been given above with reference to FIG. 3.
  • the decoding apparatus performs refinement on a specific candidate based on the merge index in operation S930. That is, the specific candidate may be a target candidate of refinement, and it may be determined whether refinement is performed based on the merge index or the MERGE_INDEX.
  • refinement may be performed on the specific candidate only when the merge index is zero.
  • the specific candidate may be referred to as a merge candidate or may be a candidate indicating when the merge index is zero. Since the merge candidate having the merge index of 0 has the highest prediction accuracy among the candidates in the candidate list, refinement is performed only on these candidates, and refinement may be performed to expect higher accuracy. In addition, the number of refinements is also reduced, so that the complexity of the decoder can be simultaneously reduced.
  • refinement when the above-described candidate is a subblock unit, refinement may not be performed, and for this, it may be determined whether the above-described candidate is a subblock unit. In addition, when the above-described candidate is a subblock unit, refinement may be performed on the next-order candidate, and the refinement may not be performed on the next-order candidate.
  • refinement may be performed on the specific candidate only when the merge index is less than or equal to a specific value. This is because if the refinement is applied only when the merge index is 0, the complexity of the decoder is reduced, but the compression efficiency may decrease as the target of the refinement decreases.
  • the specific value may be represented by N, and N may have a value ranging from 0 to the maximum number of merge candidates in consideration of complexity. For example, when N is 1, refinement may be performed on up to two candidates.
  • the decoding apparatus adds the specific candidate that performed the refinement to the merge candidate list (S940).
  • the refined candidate may be stored in the candidate list in place of a specific candidate or target candidate. That is, the target candidate may be replaced with a refined candidate. Alternatively, the refined candidate may be added to the candidate list.
  • the merge candidate list may add modified candidates.
  • the modified candidate may include candidates scaled by integer pels based on a motion vector of a specific candidate.
  • the modified candidate can be calculated based on RefinedMV and DeltaMV.
  • RefinedMV may be referred to as a motion vector or refined motion vector of a candidate on which refinement is performed
  • DeltaMV may be referred to as a delta motion vector.
  • DeltaMV may indicate a position of +1 or -1 in integer pel units based on RefinedMV and may be scaled.
  • it is not limited to the purified water pel, sub-pel or quarter-pel unit may be used. A more detailed description has been given above with reference to FIG. 7.
  • the decoding apparatus generates a predicted block for the current block based on the merge candidate list (S950). That is, the prediction of the current block may be performed based on the motion information.
  • a prediction block of the current block may be derived based on the motion information, and a reconstruction block may be derived based on the prediction block.
  • the decoding apparatus may derive a reference block within a reference picture based on the motion information.
  • the motion information may include a motion vector and a reference picture index.
  • the decoding apparatus may derive the reference picture indicated by the reference picture index among the reference pictures of the reference picture list as the reference picture of the current block, and convert the block indicated by the motion vector in the reference picture as the reference block of the current block. Can be derived.
  • the decoding apparatus may generate a prediction sample based on the reference block, and may directly use the prediction sample as a reconstruction sample according to a prediction mode, or generate a reconstruction sample by adding a residual sample to the prediction sample. . If there is a residual sample for the current block, the decoding apparatus may obtain information about the residual for the current block from the bitstream. The information about the residual may include transform coefficients regarding the residual sample. The decoding apparatus may derive the residual sample (or residual sample array) for the current block based on the residual information. The decoding apparatus may generate a reconstructed sample based on the prediction sample and the residual sample, and may derive a reconstructed block or a reconstructed picture based on the reconstructed sample. Thereafter, as described above, the decoding apparatus may apply an in-loop filtering procedure, such as a deblocking filtering and / or SAO procedure, to the reconstructed picture in order to improve subjective / objective picture quality as necessary.
  • an in-loop filtering procedure such as a deblocking filtering
  • the above-described method according to the present invention may be implemented in software, and the encoding device and / or the decoding device according to the present invention may perform image processing of, for example, a TV, a computer, a smartphone, a set-top box, a display device, and the like. It can be included in the device.
  • the above-described method may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in memory and executed by a processor.
  • the memory may be internal or external to the processor and may be coupled to the processor by various well known means.
  • the processor may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices.
  • the memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device.
  • FIG. 10 schematically illustrates the structure of a content streaming system.
  • the embodiments described in the present invention may be implemented and performed on a processor, a microprocessor, a controller or a chip.
  • the functional units shown in each drawing may be implemented and performed on a computer, processor, microprocessor, controller, or chip.
  • the decoding apparatus and encoding apparatus to which the present invention is applied include a multimedia broadcasting transmitting and receiving device, a mobile communication terminal, a home cinema video device, a digital cinema video device, a surveillance camera, a video chat device, a real time communication device such as video communication, and mobile streaming.
  • the OTT video device may include a game console, a Blu-ray player, an internet access TV, a home theater system, a smartphone, a tablet PC, a digital video recorder (DVR), and the like.
  • the processing method to which the present invention is applied can be produced in the form of a program executed by a computer, and can be stored in a computer-readable recording medium.
  • Multimedia data having a data structure according to the present invention can also be stored in a computer-readable recording medium.
  • the computer readable recording medium includes all kinds of storage devices and distributed storage devices in which computer readable data is stored.
  • the computer-readable recording medium may be, for example, a Blu-ray disc (BD), a universal serial bus (USB), a ROM, a PROM, an EPROM, an EEPROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, and an optical disc. It may include a data storage device.
  • the computer-readable recording medium also includes media embodied in the form of a carrier wave (for example, transmission over the Internet).
  • the bitstream generated by the encoding method may be stored in a computer-readable recording medium or transmitted through a wired or wireless communication network.
  • an embodiment of the present invention may be implemented as a computer program product by program code, which may be performed on a computer by an embodiment of the present invention.
  • the program code may be stored on a carrier readable by a computer.
  • the content streaming system to which the present invention is applied may largely include an encoding server, a streaming server, a web server, a media storage, a user device, and a multimedia input device.
  • the encoding server compresses content input from multimedia input devices such as a smart phone, a camera, a camcorder, etc. into digital data to generate a bitstream and transmit the bitstream to the streaming server.
  • multimedia input devices such as smart phones, cameras, camcorders, etc. directly generate a bitstream
  • the encoding server may be omitted.
  • the bitstream may be generated by an encoding method or a bitstream generation method to which the present invention is applied, and the streaming server may temporarily store the bitstream in the process of transmitting or receiving the bitstream.
  • the streaming server transmits the multimedia data to the user device based on the user's request through the web server, and the web server serves as a medium for informing the user of what service.
  • the web server delivers it to a streaming server, and the streaming server transmits multimedia data to the user.
  • the content streaming system may include a separate control server.
  • the control server plays a role of controlling a command / response between devices in the content streaming system.
  • the streaming server may receive content from a media store and / or an encoding server. For example, when the content is received from the encoding server, the content may be received in real time. In this case, in order to provide a smooth streaming service, the streaming server may store the bitstream for a predetermined time.
  • Examples of the user device include a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), navigation, a slate PC, Tablet PCs, ultrabooks, wearable devices, such as smartwatches, glass glasses, head mounted displays, digital TVs, desktops Computer, digital signage, and the like.
  • PDA personal digital assistant
  • PMP portable multimedia player
  • navigation a slate PC
  • Tablet PCs tablet PCs
  • ultrabooks wearable devices, such as smartwatches, glass glasses, head mounted displays, digital TVs, desktops Computer, digital signage, and the like.
  • Each server in the content streaming system may be operated as a distributed server, in which case data received from each server may be distributed.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

La présente invention concerne un procédé de décodage d'une image par un appareil de décodage. Le procédé comprend les étapes consistant à : dériver un indice de fusion d'un bloc actuel ; configurer une liste de candidats de fusion du bloc actuel ; dériver un candidat particulier de la liste de candidats de fusion selon qu'il faut réagencer la liste de candidats de fusion ou non ; affiner le candidat particulier sur la base de l'indice de fusion ; ajouter le candidat particulier affiné à la liste de candidats de fusion ; et générer un bloc prédit du bloc actuel sur la base de la liste de candidats de fusion.
PCT/KR2019/007719 2018-06-27 2019-06-26 Procédé et dispositif pour traiter une image selon un mode d'inter-prédiction dans un système de codage d'image WO2020004931A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023061305A1 (fr) * 2021-10-11 2023-04-20 Beijing Bytedance Network Technology Co., Ltd. Procédé, appareil et support de traitement vidéo
GB2617568A (en) * 2022-04-11 2023-10-18 Canon Kk Video coding and decoding

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160286229A1 (en) * 2015-03-27 2016-09-29 Qualcomm Incorporated Motion vector derivation in video coding
WO2017084512A1 (fr) * 2015-11-20 2017-05-26 Mediatek Inc. Procédé et appareil de prédiction de vecteur de mouvement ou de dérivation de candidat à la fusion lors d'un codage vidéo
KR20180058233A (ko) * 2010-09-02 2018-05-31 엘지전자 주식회사 영상 부호화 및 복호화 방법과 이를 이용한 장치
KR20180061060A (ko) * 2016-11-28 2018-06-07 한국전자통신연구원 영상 부호화/복호화 방법, 장치 및 비트스트림을 저장한 기록 매체

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20180058233A (ko) * 2010-09-02 2018-05-31 엘지전자 주식회사 영상 부호화 및 복호화 방법과 이를 이용한 장치
US20160286229A1 (en) * 2015-03-27 2016-09-29 Qualcomm Incorporated Motion vector derivation in video coding
WO2017084512A1 (fr) * 2015-11-20 2017-05-26 Mediatek Inc. Procédé et appareil de prédiction de vecteur de mouvement ou de dérivation de candidat à la fusion lors d'un codage vidéo
KR20180061060A (ko) * 2016-11-28 2018-06-07 한국전자통신연구원 영상 부호화/복호화 방법, 장치 및 비트스트림을 저장한 기록 매체

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
MOONMO KOO: "Description of SDR video coding technology proposal by LG Electronics", JVET-J0017-VL, JOINT VIDEO EXPERTS TEAM (JVET) OF ITU-T SG 16 WP 3 AND ISO/IEC JTC 1/SC 29/WG 11, 10TH MEETING, 11 April 2018 (2018-04-11), San Diego , CA, XP030151178 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023061305A1 (fr) * 2021-10-11 2023-04-20 Beijing Bytedance Network Technology Co., Ltd. Procédé, appareil et support de traitement vidéo
GB2617568A (en) * 2022-04-11 2023-10-18 Canon Kk Video coding and decoding

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