WO2020009375A1 - Procédé et dispositif de prédiction intra dans un système de codage d'image - Google Patents

Procédé et dispositif de prédiction intra dans un système de codage d'image Download PDF

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WO2020009375A1
WO2020009375A1 PCT/KR2019/007825 KR2019007825W WO2020009375A1 WO 2020009375 A1 WO2020009375 A1 WO 2020009375A1 KR 2019007825 W KR2019007825 W KR 2019007825W WO 2020009375 A1 WO2020009375 A1 WO 2020009375A1
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intra prediction
prediction mode
block
mode
current block
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English (en)
Korean (ko)
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이령
임재현
허진
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LG Electronics Inc
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LG Electronics Inc
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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
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/103—Selection of coding mode or of prediction mode
    • H04N19/11—Selection of coding mode or of prediction mode among a plurality of spatial predictive coding modes
    • 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
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/119—Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
    • 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
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/132—Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
    • 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
    • H04N19/593—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving spatial prediction techniques

Definitions

  • the present invention relates to image coding technology, and more particularly, to an intra prediction method and apparatus 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 technical problem of the present invention is to provide an efficient intra prediction method and apparatus.
  • Another object of the present invention is to provide a method and apparatus for determining an order of constructing an MPM list of a current block based on intra prediction modes of neighboring blocks.
  • an image decoding method performed by a decoding apparatus.
  • the method may include obtaining a Most Probable Mode (MPM) index of a current block, constructing an MPM list based on neighboring blocks of the current block, intra prediction of the current block based on the MPM list and the MPM index. Deriving a mode and generating a predicted block for the current block based on the intra prediction mode, wherein the MPM list is organized in a specific order, wherein the specific order is 2 of the neighboring blocks. And derived based on intra prediction modes of the specific neighboring blocks.
  • MCM Most Probable Mode
  • a decoding apparatus for performing image decoding.
  • the decoding apparatus obtains an entropy decoding unit for obtaining prediction information on a current block and a Most Probable Mode (MPM) index of the current block, forms an MPM list based on neighboring blocks of the current block, and generates the MPM list.
  • a predictor configured to derive an intra prediction mode of the current block based on the MPM index, and generate a predicted block for the current block based on the intra prediction mode, wherein the MPM list is configured in a specific order.
  • the specific order may be derived based on intra prediction modes of two specific neighboring blocks of the neighboring blocks.
  • a video encoding method performed by an encoding apparatus includes constructing a Most Probable Mode (MPM) list based on neighboring blocks of the current block, deriving an intra prediction mode of the current block based on the MPM list, and deriving an MPM index of the current block. Generating a predicted block for the current block based on the intra prediction mode, and generating, encoding and outputting prediction information for the current block including the MPM index, wherein the MPM list Is configured according to a specific order, and the specific order is derived based on intra prediction modes of two specific neighboring blocks of the neighboring blocks.
  • MPM Most Probable Mode
  • a video encoding apparatus constructs a Most Probable Mode (MPM) list based on neighboring blocks of the current block, derives an intra prediction mode of the current block based on the MPM list, derives an MPM index of the current block, A prediction unit for generating a predicted block for the current block based on the intra prediction mode, and an entropy encoding unit for generating, encoding and outputting prediction information for the current block including the MPM index, wherein the MPM list Is configured according to a specific order, and the specific order is derived based on intra prediction modes of two specific neighboring blocks of the neighboring blocks.
  • MPM Most Probable Mode
  • image compression efficiency can be improved.
  • the intra prediction mode can be efficiently derived while reducing the computational complexity.
  • 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. 5 schematically illustrates an image encoding method by an encoding apparatus according to the present invention.
  • FIG. 6 schematically illustrates an image decoding method by a decoding apparatus according to the present invention.
  • FIG. 7 schematically shows the structure of a content streaming system.
  • 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 (ex. 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 tree structure.
  • the quad tree structure may be applied first and the binary tree structure and / or ternary tree 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.
  • Intra prediction may refer to prediction that generates prediction samples for the current block based on reference samples in a picture to which the current block belongs (hereinafter, referred to as a current picture).
  • peripheral reference samples to be used for intra prediction of the current block may be derived.
  • the peripheral reference samples of the current block are samples adjacent to the left boundary of the current block of size nWxnH and a total of 2xnH samples neighboring the bottom-left, and samples adjacent to the top boundary of the current block. And a total of 2xnW samples neighboring the top-right and one sample neighboring the top-left of the current block.
  • the peripheral reference samples of the current block may include a plurality of upper peripheral samples and a plurality of left peripheral samples.
  • peripheral reference samples of the current block are a total of nH samples adjacent to the right boundary of the current block of size nWxnH, a total of nW samples adjacent to the bottom boundary of the current block and the lower right side of the current block. It may include one sample neighboring (bottom-right).
  • peripheral reference samples of the current block may not be decoded yet or available.
  • the decoder may construct the surrounding reference samples to use for prediction by substituting the samples that are not available with the available samples.
  • peripheral reference samples to be used for prediction may be configured through interpolation of the available samples.
  • the prediction sample can be derived based on the average or interpolation of neighboring reference samples of the current block, and (ii) the neighbor reference samples of the current block.
  • the prediction sample may be derived based on a reference sample present in a specific (prediction) direction with respect to the prediction sample. In case of (i), it may be called non-directional mode or non-angle mode, and in case of (ii), it may be called directional mode or angular mode.
  • the interpolation between the second neighboring sample and the first neighboring sample located in a direction opposite to the prediction direction of the intra prediction mode of the current block based on the prediction sample of the current block among the neighboring reference samples may be performed.
  • Prediction samples may be generated.
  • LIP linear interpolation intra prediction
  • chroma prediction samples may be generated based on luma samples using a linear model. In this case, it may be called LM mode.
  • a temporary prediction sample of the current block is derived based on filtered neighbor reference samples, and at least one of the existing neighbor reference samples, that is, unfiltered neighbor reference samples, derived according to the intra prediction mode.
  • a weighted sum of a reference sample and the temporary prediction sample may be used to derive the prediction sample of the current block.
  • the above case may be referred to as position dependent intra prediction (PDPC).
  • a reference sample line having the highest prediction accuracy among the neighboring multi-reference sample lines of the current block is selected to derive the prediction sample by using the reference sample located in the prediction direction on the corresponding line, and then decode the used reference sample line.
  • Intra-prediction encoding may be performed by instructing (signaling) the device. The above case may be referred to as multi-reference line (MRL) intra prediction or MRL based intra prediction.
  • MRL multi-reference line
  • intra prediction may be performed based on the same intra prediction mode by dividing the current block into vertical or horizontal subpartitions, and peripheral reference samples may be derived and used in units of the subpartition. That is, in this case, the intra prediction mode for the current block is equally applied to the subpartitions, and the intra prediction performance may be improved in some cases by deriving and using the peripheral reference samples in the subpartition unit.
  • Such a prediction method may be called intra sub-partitions (ISP) or ISP based intra prediction.
  • the above-described intra prediction methods may be called an intra prediction type separately from the intra prediction mode.
  • the intra prediction type may be called in various terms such as an intra prediction technique or an additional intra prediction mode.
  • the intra prediction type (or additional intra prediction mode) may include at least one of the above-described LIP, PDPC, MRL, and ISP.
  • a general intra prediction method except for a specific intra prediction type such as LIP, PDPC, MRL, or ISP may be called a normal intra prediction type.
  • the normal intra prediction type may be generally applied when the specific intra prediction type is not applied, and prediction may be performed based on the intra prediction mode described above. Meanwhile, post-processing filtering may be performed on the predicted sample derived as needed.
  • the intra prediction procedure may include an intra prediction mode / type determination step, a peripheral reference sample derivation step, and an intra prediction mode / type based prediction sample derivation step.
  • a post-filtering step may be performed on the predicted sample derived as needed.
  • affine linear weighted intra prediction may be used.
  • the ALWIP may be referred to as linear weighted intra prediction (LWIP) or matrix weighted intra prediction or matrix based intra prediction (MIP). If the MIP is applied to the current block, i) perform ii) matrix-vector-multiplication procedure using peripheral reference samples on which an averaging procedure has been performed, and iii) if necessary. Accordingly, a horizontal / vertical interpolation procedure may be further performed to derive prediction samples for the current block.
  • the intra prediction modes used for the MIP may be configured differently from the intra prediction modes used in the LIP, PDPC, MRL, ISP intra prediction, or normal intra prediction.
  • the intra prediction mode for the MIP may be called a MIP intra prediction mode, a MIP prediction mode or a MIP mode.
  • the matrix and offset used in the matrix vector multiplication may be set differently according to the intra prediction mode for the MIP.
  • the matrix may be called a (MIP) weighting matrix
  • the offset may be called a (MIP) offset vector or a (MIP) bias vector.
  • the intra prediction mode applied to the current block may be determined using the intra prediction mode of the neighboring block.
  • the decoding apparatus receives one of the MPM candidates in the most probable mode (MPM) list derived based on the intra prediction mode and additional candidate modes of the neighboring block (eg, left and / or upper neighboring block) of the current block.
  • the selected MPM index may be selected or one of the remaining intra prediction modes not included in the MPM candidates (and planner mode) may be selected based on the remaining intra prediction mode information.
  • the MPM list may be configured to include or not include a planner mode as a candidate. For example, when the MPM list includes a planner mode as a candidate, the MPM list may have six candidates.
  • the MPM list may have three or five candidates. You can have a candidate.
  • a not planner flag eg, intra_luma_not_planar_flag
  • the MPM flag is signaled first, and the MPM index and not planner flag may be signaled when the value of the MPM flag is one.
  • the MPM index may be signaled when the value of the not planner flag is 1.
  • the configuration of the MPM list not to include a planner mode as a candidate is not that the planner mode is not an MPM, but rather a signal that is not a planar flag first because a planner mode is always considered as an MPM. To check whether the mode is first.
  • the intra prediction mode applied to the current block is in MPM candidates (and planner mode) or in remaining mode may be indicated based on the MPM flag (ex. Intra_luma_mpm_flag).
  • a value of 1 of the MPM flag may indicate that the intra prediction mode for the current block is within MPM candidates (and planner mode), and a value of 0 of the MPM flag indicates that the intra prediction mode for the current block is the MPM candidates (and planner mode). ) May be absent.
  • the not planar flag (ex. Intra_luma_not_planar_flag) value 0 may indicate that the intra prediction mode for the current block is planner mode, and the not planar flag value 1 indicates that the intra prediction mode for the current block is not planner mode. Can be.
  • the MPM index may be signaled in the form of an mpm_idx or intra_luma_mpm_idx syntax element, and the remaining intra prediction mode information may be signaled in the form of a rem_intra_luma_pred_mode or intra_luma_mpm_remainder syntax element.
  • the remaining intra prediction mode information may index remaining intra prediction modes not included in the MPM candidates (and planner mode) among all intra prediction modes in order of prediction mode number to indicate one of them.
  • the intra prediction mode may be an intra prediction mode for a luma component (sample).
  • intra prediction mode information includes the MPM flag (ex. Intra_luma_mpm_flag), the not planar flag (ex.
  • Intra_luma_not_planar_flag the MPM index (ex. Mpm_idx or intra_luma_mpm_idx), and the remaining intra prediction mode information (rem_intra_luma_prem_mode). It may include at least one.
  • the MPM list may be referred to in various terms such as MPM candidate list and candModeList.
  • the encoder can use the intra prediction mode of the neighboring block to encode the intra prediction mode of the current block.
  • the encoder / decoder may construct a list of most probable modes (MPM) for the current block.
  • the MPM list may also be referred to as an MPM candidate list.
  • the MPM may refer to a mode used to improve coding efficiency in consideration of similarity between the current block and neighboring blocks in intra prediction mode coding.
  • the MPM list may be configured to include a planner mode, or may be configured to exclude a planner mode. For example, when the MPM list includes a planner mode, the number of candidates in the MPM list may be six. And, if the MPM list does not include the planner mode, the number of candidates in the MPM list may be five.
  • the encoder / decoder may construct an MPM list including six MPMs.
  • Default intra modes Three kinds of modes can be considered to construct the MPM list: Default intra modes, Neighbor intra modes, and Derived intra modes.
  • two peripheral blocks i.e., a left peripheral block and an upper peripheral block, may be considered.
  • the MPM list is configured not to include the planner mode, the planar mode is excluded from the list, and the number of the MPM list candidates may be set to five.
  • the directional mode or the angular mode among the intra modes has a vertical directionality and an intra prediction mode having a horizontal directionality around the intra prediction mode 34 having a left upward diagonal prediction direction.
  • Intra prediction mode can be distinguished.
  • H and V in FIG. 3 mean horizontal directionality and vertical directionality, respectively, and numbers of -32 to 32 represent a displacement of 1/32 on a sample grid position.
  • Intra prediction modes 2 to 33 have horizontal orientation, and intra prediction modes 34 to 66 have vertical orientation.
  • Intra prediction mode 18 and intra prediction mode 50 indicate a horizontal intra prediction mode and a vertical intra prediction mode, respectively, and an intra prediction mode 2 indicates a left downward diagonal intra prediction mode,
  • the 34th intra prediction mode may be referred to as a left upward diagonal intra prediction mode, and the 66th intra prediction mode may be referred to as a right upward diagonal intra prediction mode.
  • non-directional mode or the non-angle mode may include an average based DC mode or an interpolation based planar mode of neighboring reference samples of the current block.
  • an intra prediction mode applied to the current block may be derived based on the intra prediction mode of the neighboring block of the current block.
  • the decoding apparatus may derive the most probable mode (MPM) list based on the intra prediction mode and additional candidate modes of the neighboring block (eg, the left neighboring block and / or the upper neighboring block) of the current block.
  • MPM most probable mode
  • One of the MPM candidates in the derived MPM list may be selected based on the received MPM index, or one of the remaining intra prediction modes not included in the MPM candidates is based on intra prediction mode information. Can be selected.
  • Whether an intra prediction mode of the current block exists in the MPM list may be indicated based on an MPM flag.
  • the MPM list may be referred to as an intra prediction mode candidate list or may be referred to as candModeList.
  • the MPM list may include three, five, or six MPM candidates.
  • the MPM list may include candidates derived based on an intra prediction mode, a derived intra prediction mode, and / or a default intra prediction mode of a neighboring block.
  • the encoding device / decoding device may search the neighboring blocks of the current block in a specific order and derive the intra prediction mode of the neighboring block as the MPM candidate in the derived order.
  • the neighboring blocks may include a left neighboring block, an upper neighboring block, a lower left neighboring block, a right upper neighboring block, and an upper left neighboring block
  • the encoding device / decoding device is an intra prediction mode of the left neighboring block.
  • Intra prediction mode of the upper neighboring block may be derived and the MPM list of the current block may be constructed. Meanwhile, if six MPM candidates are not derived after the search, an MPM candidate may be derived based on an intra prediction mode derived as the MPM candidate. For example, when the intra prediction mode derived as the MPM candidate is N intra prediction mode, the encoding device / decoding device selects the N + 1 intra prediction mode and / or the N-1 intra prediction mode from the current block. Can be derived as an MPM candidate. A detailed description of the neighboring blocks will be described later.
  • an intra prediction mode applied to the current block is included in the MPM candidates or the remaining intra prediction modes may be derived based on an MPM flag.
  • the MPM flag may indicate that the intra prediction mode of the current block is included in MPM candidates (MPM list)
  • MPM list when the value of the MPM flag is 0, the MPM The flag may indicate that the intra prediction mode for the current block is included in the remaining intra prediction modes rather than included in MPM candidates (MPM list).
  • the encoding apparatus may derive an MPM list for the current block based on the intra prediction mode and additional candidate modes of the neighboring block of the current block, determine the intra prediction mode of the current block, and determine the current block.
  • Intra prediction mode information for may be encoded and stored and / or transmitted.
  • Cur represents a block to be currently coded, that is, a current block.
  • A, B, C, D and E represent neighboring blocks of the current block.
  • the initial MPM list may be configured with intra modes, planner mode, and DC mode of five neighboring blocks, and a pruning process may be performed to remove the overlapping modes in the MPM list. .
  • five neighboring blocks may be searched, and the left neighboring block (A), the upper neighboring block (B), the lower left neighboring block (D), the upper right neighboring block (C), and The neighboring blocks may be searched in the order of the upper left neighboring block E to derive the intra prediction mode around the current block.
  • the position of the neighboring block to be searched and the search order of the neighboring block may be predetermined or arbitrarily determined.
  • the initial MPM list includes the intra prediction mode of the left neighboring block A, the intra prediction mode of the upper neighboring block B, the planar mode, the DC mode, the intra prediction mode of the lower left neighboring block D, and the upper right corner.
  • the intra prediction mode of the side neighboring block C and the intra prediction mode of the upper left neighboring block E may be configured in this order.
  • a pruning process may be performed on the initial MPM list configured as described above, and duplicate duplicate MPM candidates may be removed. Accordingly, the number of MPM candidates in the MPM list may be less than six, and in this case, the derived intra mode may be added to the MPM list.
  • This intra mode may be derived as a mode that is -1 or +1 with respect to the angle mode included in the MPM list.
  • the MPM candidate mode determination method ends.
  • a default intra mode may be further added.
  • the order in which the default intra mode is added may be a vertical intra prediction mode, a horizontal intra prediction mode, and a diagonal intra prediction mode.
  • the diagonal intra prediction mode may indicate the 34th intra prediction mode.
  • the MPM list may consist of six MPM candidates or six modes that are not unique or redundant.
  • the number in the MPM list may be six when the planner mode is included in the MPM list, or five when the planner mode is not included, but is not limited thereto.
  • the order of configuring the above-described MPM list may be changed as follows according to a condition.
  • the order of constructing the MPM list is determined by the upper neighboring block of the current block ( Intra prediction mode of B), intra prediction mode of left peripheral block A, planner mode, DC mode, intra prediction mode of right upper peripheral block C, intra prediction mode of upper left peripheral block E, and lower left side It may be an intra prediction mode of the neighboring block D.
  • the order of constructing the MPM list is determined by the left neighboring block of the current block ( Intra prediction mode of A), intra prediction mode of upper peripheral block (B), planner mode, DC mode, intra prediction mode of lower left peripheral block (D), intra prediction mode of upper right peripheral block (C) and upper left side It may be an intra prediction mode of the neighboring block E.
  • the intra prediction mode of the upper left neighboring block E of the current block is not similar to the intra prediction mode of the left neighboring block A of the current block, and also similar to the intra prediction mode of the upper neighboring block B.
  • the order of constructing the MPM list includes the intra prediction mode of the left neighboring block A of the current block, the intra prediction mode of the upper neighboring block B, the planar mode, the DC mode, and the lower left neighboring block D of the current block. It may be an intra prediction mode, an intra prediction mode of the upper left peripheral block E, and an intra prediction mode of the right upper peripheral block C.
  • the order of configuring the above-described MPM list may be changed as follows according to a condition.
  • the order of constructing the MPM list is the upper side of the current block.
  • an intra prediction mode of the lower left neighboring block D That is, the order may be B-> A-> planar-> C-> E-> DC-> D.
  • the similarity between the intra prediction mode of the first neighboring block and the second neighboring block of the current block means that the difference between the number of the intra prediction mode of the first neighboring block and the number of the intra prediction modes of the second neighboring block is equal to or less than a specific value. It may mean less than.
  • the specific value may be 2, and when the difference is less than 2, it may be considered that the intra prediction modes of the first neighboring block and the second neighboring block are similar.
  • the intra prediction mode of each neighboring block may be a directional mode or an angular mode, and similarity or similarity may not be considered when the intra prediction mode of each neighboring block is the non-directional mode or the non-angle mode.
  • the intra prediction mode of the upper left neighboring block E of the current block Cur described above is similar to the intra prediction mode of the left neighboring block A of the current block
  • the intra prediction mode of the upper left neighboring block E is similar.
  • the intra prediction modes of the left neighboring block A are both directional or angular mode, and the difference between the number of the intra prediction mode of the upper left neighboring block E and the number of the intra prediction modes of the left neighboring block A is 2 It can mean something smaller.
  • the B BD rate rate that is, the Bj ⁇ ntegaard Distortion rate of luminance
  • the Bj ⁇ ntegaard Distortion rate of luminance may be different from that of changing the order of constructing the MPM list according to an embodiment. Can be reduced, and coding efficiency can be improved.
  • FIG. 5 schematically illustrates an image encoding method by an encoding apparatus according to the present invention.
  • the method disclosed in FIG. 5 may be performed by the encoding apparatus disclosed in FIG. 1. Specifically, for example, S500 to S530 of FIG. 5 may be performed by the prediction unit of the encoding apparatus, and S540 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 an MPM list based on neighboring blocks of the current block (S500).
  • the MPM list may be referred to in various terms such as the MPM candidate list and the candModeList.
  • the MPM list may be configured to include or not include a planner mode as a candidate. For example, when the MPM list includes a planner mode as a candidate, the MPM list may have six candidates. When the MPM list does not include a planner mode as a candidate, the MPM list may have three or five candidates. You can have a candidate. When the MPM list does not include a planner mode as a candidate, a not planner flag (eg, intra_luma_not_planar_flag) indicating whether an intra prediction mode of the current block is not a planner mode may be signaled.
  • intra_luma_not_planar_flag indicating whether an intra prediction mode of the current block is not a planner mode
  • three kinds of modes can be considered to construct an MPM list: Default intra modes, Neighbor intra modes, and Derived intra modes. And may be configured in the order of peripheral intra modes, derived intra modes, and default intra modes.
  • the MPM list may be configured according to a specific order, and the specific order may be derived based on intra prediction modes of two specific neighboring blocks of the neighboring blocks.
  • the specific order may indicate the order in the case of configuring the MPM list based on the intra intra modes, that is, the intra prediction modes of the neighbor blocks of the current block.
  • the specific order may be derived based on a difference value between numbers of intra prediction modes of the two specific neighboring blocks.
  • the difference between the numbers of the intra prediction modes of the two specific neighboring blocks may indicate the similarity or similarity of the intra prediction modes of the two specific neighboring blocks.
  • the two specific blocks may include an upper left neighboring block of the current block and a left neighboring block of the current block.
  • the upper left peripheral block and the left peripheral block may be adjacent to the current block.
  • the intra prediction mode of the upper left neighboring block and the intra prediction mode of the left neighboring block may be a directional mode or an angular mode.
  • the specific order may include intra prediction mode of the upper neighboring block of the current block, intra prediction mode of the left neighboring block, planar mode, and intra of the right upper neighboring block when the difference value is smaller than a specific value.
  • the order of the prediction mode, the intra prediction mode of the upper left neighboring block, the DC mode, and the intra prediction mode of the lower left neighboring block may be included. That is, referring to FIG. 4, B-> A-> planar-> C-> E-> DC-> D order.
  • the specific order may include intra prediction mode of the left neighboring block of the current block, intra prediction mode of the upper neighboring block, planar mode, and intra prediction of the lower left neighboring block when the difference value is not smaller than a specific value.
  • the intra prediction mode of the upper left neighboring block the DC mode, and the intra prediction mode of the upper right neighboring block. That is, referring to FIG. 4, A-> B-> planar-> D-> E-> DC-> C order.
  • the specific value may be 2, but is not limited thereto.
  • the specific order is that the intra prediction mode of the upper left neighboring block of the current block is similar to the intra prediction mode of the left neighboring block of the current block, the intra prediction mode of the upper neighboring block of the current block, the intra of the left neighboring block.
  • the intra prediction mode of the upper left neighboring block of the current block is similar to the intra prediction mode of the upper neighboring block of the current block, the intra prediction mode of the left neighboring block of the current block, the intra prediction mode of the upper neighboring block, the planner mode, DC Mode, the intra prediction mode of the lower left neighboring block, the intra prediction mode of the upper right neighboring block, and the intra prediction mode of the upper left neighboring block.
  • the intra prediction mode of the upper left neighboring block of the current block is not similar to the intra prediction mode of the left neighboring block of the current block, and is not similar to the intra prediction mode of the upper neighboring block, the intra of the left neighboring block of the current block.
  • the MPM list may be configured based on neighboring intra modes, and then may be subjected to pruning to remove duplicate candidates, and the number of candidates in the MPM list may be maximized by removing duplicate candidates. If the number is less than three, five, or six, the MPM list may be further configured based on the derived intra modes. That is, candidates may be further added to the MPM list. Thereafter, pruning may be performed. In addition, if the number of candidates in the MPM list is still less than the maximum number, a default intra mode may be further added. Accordingly, the MPM list may consist of the maximum number of MPM candidates or modes that are unique or not duplicated.
  • the encoding apparatus derives the intra prediction mode of the current block based on the MPM list (S510). That is, an intra prediction mode for prediction of the current block among candidates in the MPM list may be derived. Alternatively, a candidate for prediction of the current block among the candidates in the MPM list may be selected, and an intra prediction mode of the selected candidate may be derived.
  • the encoding apparatus derives the MPM index of the current block (S520).
  • the MPM index may mean information indicating one of the MPM candidates included in the MPM list. That is, the MPM index may be information indicating a candidate having an intra prediction mode derived for prediction of the current block among candidates in the MPM list.
  • the MPM index may be referred to as an index, and the MPM index may be signaled in the form of an mpm_idx or intra_luma_mpm_idx syntax element.
  • the encoding apparatus generates a predicted block for the current block based on the intra prediction mode (S530).
  • the derived intra prediction mode may be a directional mode or a non-directional mode.
  • the encoding apparatus may generate a prediction sample based on the intra prediction mode, and may use the prediction sample directly as a reconstruction sample according to the prediction mode.
  • 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.
  • 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 generates, encodes, and outputs prediction information about the current block including the MPM index (S540).
  • 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 about the MPM index 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. 6 schematically illustrates an image decoding method by a decoding apparatus according to the present invention.
  • the method disclosed in FIG. 6 may be performed by the decoding apparatus disclosed in FIG. 2. Specifically, for example, S600 to S630 of FIG. 6 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 obtains an MPM index of the current block (S600).
  • the MPM index may mean information indicating one of the MPM candidates included in the MPM list. That is, intra prediction may be performed based on the MPM candidate indicated by the MPM index.
  • the MPM index may be referred to as an index, and the MPM index may be signaled in the form of an mpm_idx or intra_luma_mpm_idx syntax element.
  • the decoding apparatus configures an MPM list based on neighboring blocks of the current block (S610).
  • the MPM list may be referred to in various terms such as the MPM candidate list and the candModeList.
  • the MPM list may be configured to include or not include a planner mode as a candidate. For example, when the MPM list includes a planner mode as a candidate, the MPM list may have six candidates. When the MPM list does not include a planner mode as a candidate, the MPM list may have three or five candidates. You can have a candidate. When the MPM list does not include a planner mode as a candidate, a not planner flag (eg, intra_luma_not_planar_flag) indicating whether an intra prediction mode of the current block is not a planner mode may be signaled.
  • intra_luma_not_planar_flag indicating whether an intra prediction mode of the current block is not a planner mode
  • three kinds of modes can be considered to construct an MPM list: Default intra modes, Neighbor intra modes, and Derived intra modes. And may be configured in the order of peripheral intra modes, derived intra modes, and default intra modes.
  • the MPM list may be configured according to a specific order, and the specific order may be derived based on intra prediction modes of two specific neighboring blocks of the neighboring blocks.
  • the specific order may indicate the order in the case of configuring the MPM list based on the intra intra modes, that is, the intra prediction modes of the neighbor blocks of the current block.
  • the specific order may be derived based on a difference value between numbers of intra prediction modes of the two specific neighboring blocks.
  • the difference between the numbers of the intra prediction modes of the two specific neighboring blocks may indicate the similarity or similarity of the intra prediction modes of the two specific neighboring blocks.
  • the two specific blocks may include an upper left neighboring block of the current block and a left neighboring block of the current block.
  • the upper left peripheral block and the left peripheral block may be adjacent to the current block.
  • the intra prediction mode of the upper left neighboring block and the intra prediction mode of the left neighboring block may be a directional mode or an angular mode.
  • the specific order may include intra prediction mode of the upper neighboring block of the current block, intra prediction mode of the left neighboring block, planar mode, and intra of the right upper neighboring block when the difference value is smaller than a specific value.
  • the order of the prediction mode, the intra prediction mode of the upper left peripheral block, the DC mode, and the intra prediction mode of the lower left peripheral block D may be included. That is, referring to FIG. 4, B-> A-> planar-> C-> E-> DC-> D order.
  • the specific order may include intra prediction mode of the left neighboring block of the current block, intra prediction mode of the upper neighboring block, planar mode, and intra prediction of the lower left neighboring block when the difference value is not smaller than a specific value.
  • the intra prediction mode of the upper left neighboring block the DC mode, and the intra prediction mode of the upper right neighboring block. That is, referring to FIG. 4, A-> B-> planar-> D-> E-> DC-> C order.
  • the specific value may be 2, but is not limited thereto.
  • the specific order is that the intra prediction mode of the upper left neighboring block of the current block is similar to the intra prediction mode of the left neighboring block of the current block, the intra prediction mode of the upper neighboring block of the current block, the intra of the left neighboring block.
  • the intra prediction mode of the upper left neighboring block of the current block is similar to the intra prediction mode of the upper neighboring block of the current block, the intra prediction mode of the left neighboring block of the current block, the intra prediction mode of the upper neighboring block, the planner mode, DC Mode, the intra prediction mode of the lower left neighboring block, the intra prediction mode of the upper right neighboring block, and the intra prediction mode of the upper left neighboring block.
  • the intra prediction mode of the upper left neighboring block of the current block is not similar to the intra prediction mode of the left neighboring block of the current block, and is not similar to the intra prediction mode of the upper neighboring block, the intra of the left neighboring block of the current block.
  • the MPM list may be configured based on neighboring intra modes, and then may be subjected to pruning to remove duplicate candidates, and the number of candidates in the MPM list may be maximized by removing duplicate candidates. If the number is less than three, five, or six, the MPM list may be further configured based on the derived intra modes. That is, candidates may be further added to the MPM list. Thereafter, pruning may be performed. In addition, if the number of candidates in the MPM list is still less than the maximum number, a default intra mode may be further added. Accordingly, the MPM list may consist of the maximum number of MPM candidates or modes that are unique or not duplicated.
  • the decoding apparatus derives the intra prediction mode of the current block based on the MPM index and the MPM list (S620). That is, the intra prediction mode indicated by the MPM index among the candidates in the MPM list can be derived. Alternatively, a candidate indicated or indicated by the MPM index among the candidates in the MPM list may be selected, and an intra prediction mode of the selected candidate may be derived.
  • the decoding apparatus generates a predicted block for the current block based on the intra prediction mode (S630).
  • the derived intra prediction mode may be a directional mode or a non-directional mode.
  • the decoding apparatus may generate a prediction sample based on an intra prediction mode, and may directly use the prediction sample as a reconstruction sample according to the 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 and / or SAO procedure
  • 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. 7 schematically shows 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 (eg, 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.
  • embodiments of the present invention may be implemented as a computer program product by a program code, the program code 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 smartphone, 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'image mis en œuvre par un dispositif de décodage consistant : à acquérir un indice de mode le plus probable (MPM) d'un bloc en cours ; à configurer une liste MPM en fonction de blocs voisins du bloc en cours ; à déduire un mode de prédiction intra du bloc en cours en fonction de la liste MPM et de l'indice MPM ; et à générer un bloc prédit du bloc en cours en fonction du mode de prédiction intra, la liste MPM étant configurée selon un ordre spécifique, l'ordre spécifique étant déduit en fonction de modes de prédiction intra de deux blocs voisins spécifiques parmi les blocs voisins.
PCT/KR2019/007825 2018-07-02 2019-06-27 Procédé et dispositif de prédiction intra dans un système de codage d'image Ceased WO2020009375A1 (fr)

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US11406778B2 (en) 2011-06-15 2022-08-09 Koninklijke Philips N.V. Unlocking a respiratory mode

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JP2015092721A (ja) * 2011-05-30 2015-05-14 株式会社Ｊｖｃケンウッド 画像復号装置、画像復号方法、及び画像復号プログラム、並びに、受信装置、受信方法、及び受信プログラム
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KR20180046876A (ko) * 2016-10-28 2018-05-09 한국전자통신연구원 영상 부호화/복호화 방법, 장치 및 비트스트림을 저장한 기록 매체

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KR20180008797A (ko) * 2015-06-15 2018-01-24 엘지전자 주식회사 인트라 예측 모드 기반 영상 처리 방법 및 이를 위한 장치
KR20180043149A (ko) * 2016-10-19 2018-04-27 에스케이텔레콤 주식회사 영상 부호화 또는 복호화하기 위한 장치 및 방법
KR20180046876A (ko) * 2016-10-28 2018-05-09 한국전자통신연구원 영상 부호화/복호화 방법, 장치 및 비트스트림을 저장한 기록 매체

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11406778B2 (en) 2011-06-15 2022-08-09 Koninklijke Philips N.V. Unlocking a respiratory mode

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