WO2021060940A1 - Bdpcm이 적용되는 부호화 블록에 이용되는 레지듀얼 코딩 방법을 시그널링하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 - Google Patents
Bdpcm이 적용되는 부호화 블록에 이용되는 레지듀얼 코딩 방법을 시그널링하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 Download PDFInfo
- Publication number
- WO2021060940A1 WO2021060940A1 PCT/KR2020/013150 KR2020013150W WO2021060940A1 WO 2021060940 A1 WO2021060940 A1 WO 2021060940A1 KR 2020013150 W KR2020013150 W KR 2020013150W WO 2021060940 A1 WO2021060940 A1 WO 2021060940A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- block
- transform
- residual
- current
- coding
- Prior art date
Links
Images
Classifications
-
- 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
- H04N19/46—Embedding additional information in the video signal during the compression process
-
- 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
- H04N19/103—Selection of coding mode or of prediction mode
- H04N19/105—Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
-
- 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
- H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
- H04N19/136—Incoming video signal characteristics or properties
- H04N19/137—Motion inside a coding unit, e.g. average field, frame or block difference
-
- 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
- H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
- H04N19/167—Position within a video image, e.g. region of interest [ROI]
-
- 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
- H04N19/10—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
- H04N19/18—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 a set of transform coefficients
-
- 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
- H04N19/184—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 bits, e.g. of the compressed video stream
-
- 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
- H04N19/507—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using predictive coding involving temporal prediction using conditional replenishment
-
- 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
-
- 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
- H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
-
- 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
-
- 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
- H04N19/124—Quantisation
-
- 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
- H04N19/13—Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
Definitions
- the present disclosure relates to an image encoding/decoding method and apparatus, and more particularly, an image encoding/decoding method and apparatus for encoding a residual block, and a bitstream generated by the image encoding method/apparatus of the present disclosure is transmitted. It's about how to do it.
- An object of the present disclosure is to provide a video encoding/decoding method and apparatus with improved encoding/decoding efficiency.
- an object of the present disclosure is to provide a video encoding/decoding method and apparatus for improving encoding/decoding efficiency by signaling a residual coding method used in a coding block to which BDPCM is applied.
- an object of the present disclosure is to provide a method for transmitting a bitstream generated by an image encoding method or apparatus according to the present disclosure.
- an object of the present disclosure is to provide a recording medium storing a bitstream generated by an image encoding method or apparatus according to the present disclosure.
- an object of the present disclosure is to provide a recording medium storing a bitstream that is received and decoded by an image decoding apparatus according to the present disclosure and used for restoring an image.
- An image decoding method performed by an image decoding apparatus includes: determining a residual coding method of a current transform block corresponding to a current coding block; Restoring residual information of the transform block based on the determined residual coding scheme; And restoring the current transform block based on the residual information.
- the residual coding scheme of the transform block may be determined based on whether transform skip residual coding can be performed on the current transform block. .
- an image decoding apparatus including a memory and at least one processor, wherein the at least one processor determines a residual coding method of a current transform block corresponding to a current coding block, and , The residual information of the current transform block may be restored based on the determined residual coding scheme, and the current transform block may be restored based on the residual information.
- BDPCM block based delta pulse code modulation
- the residual coding scheme of the current transform block may be determined based on whether transform skip residual coding can be performed on the current transform block. have.
- an image encoding method performed by an image encoding apparatus includes: determining a residual coding method of a current transform block corresponding to a current encoding block; Determining residual information of the current transform block based on the determined residual coding scheme; And encoding the current transform block based on the residual information.
- the residual coding scheme of the current transform block may be determined based on whether transform skip residual coding is possible to perform the transform block. .
- the transmission method according to an aspect of the present disclosure may transmit a bitstream generated by the image encoding apparatus or the image encoding method of the present disclosure.
- a computer-readable recording medium may store a bitstream generated by the image encoding method or the image encoding apparatus of the present disclosure.
- an image encoding/decoding method and apparatus with improved encoding/decoding efficiency may be provided.
- a video encoding/decoding method and apparatus capable of improving encoding/decoding efficiency by signaling a residual coding method used for a coding block to which BDPCM is applied may be provided.
- a method for transmitting a bitstream generated by an image encoding method or an apparatus according to the present disclosure may be provided.
- a recording medium storing a bitstream generated by an image encoding method or apparatus according to the present disclosure may be provided.
- a recording medium may be provided that stores a bitstream that is received and decoded by the image decoding apparatus according to the present disclosure and used for image restoration.
- FIG. 1 is a diagram schematically illustrating a video coding system to which an embodiment according to the present disclosure can be applied.
- FIG. 2 is a diagram schematically illustrating an image encoding apparatus to which an embodiment according to the present disclosure can be applied.
- FIG. 3 is a schematic diagram of an image decoding apparatus to which an embodiment according to the present disclosure can be applied.
- FIG. 4 is a diagram illustrating an image segmentation structure according to an exemplary embodiment.
- FIG. 5 is a diagram illustrating an embodiment of a block division type according to a multi-type tree structure.
- FIG. 6 is a diagram illustrating a signaling mechanism of block division information in a quadtree with nested multi-type tree structure according to the present disclosure.
- FIG. 7 is a diagram illustrating an embodiment in which a CTU is divided into multiple CUs.
- FIG. 8 is a diagram illustrating a block diagram of CABAC according to an embodiment for encoding one syntax element.
- 9 to 12 are diagrams illustrating entropy encoding and decoding according to an embodiment.
- FIG. 13 and 14 are diagrams illustrating an example of a picture decoding and encoding procedure according to an embodiment.
- 15 is a diagram illustrating a hierarchical structure of a coded image according to an embodiment.
- 16 is a diagram illustrating a peripheral reference sample according to an exemplary embodiment.
- 17 to 18 are diagrams for explaining intra prediction according to an embodiment.
- 19 to 20 are diagrams illustrating a residual processing method according to an exemplary embodiment.
- 21 to 27 are diagrams for continuously expressing residual_coding syntax.
- 29 to 31 are diagrams for continuously expressing residual_ts_coding syntax.
- 32 is a diagram for describing a method of encoding a residual sample of BDPCM, according to an embodiment.
- 33 illustrates a modified quantized residual block generated by performing BDPCM according to an embodiment.
- 34 is a flowchart illustrating a procedure for encoding a current block by applying BDPCM in an image encoding apparatus according to an embodiment.
- 35 is a flowchart illustrating a procedure for restoring a current block by applying BDPCM in an image decoding apparatus according to an embodiment.
- 36 to 38 are diagrams schematically showing syntax for signaling information about BDPCM.
- 39 to 40 are diagrams showing syntax of a TU for signaling a residual coding scheme selected for residual coding a luma component block
- 41 is a diagram illustrating an image decoding method according to an embodiment.
- FIG. 42 is a diagram illustrating an image encoding method according to an exemplary embodiment.
- FIG. 43 is a diagram illustrating a content streaming system to which an embodiment of the present disclosure can be applied.
- a component when a component is said to be “connected”, “coupled” or “connected” with another component, it is not only a direct connection relationship, but also an indirect connection relationship in which another component exists in the middle. It can also include.
- a certain component when a certain component “includes” or “have” another component, it means that other components may be further included rather than excluding other components unless otherwise stated. .
- first and second are used only for the purpose of distinguishing one component from other components, and do not limit the order or importance of the components unless otherwise noted. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment is referred to as a first component in another embodiment. It can also be called.
- components that are distinguished from each other are intended to clearly describe each feature, and do not necessarily mean that the components are separated. That is, a plurality of components may be integrated into one hardware or software unit, or one component may be distributed to form a plurality of hardware or software units. Therefore, even if not stated otherwise, such integrated or distributed embodiments are also included in the scope of the present disclosure.
- components described in various embodiments do not necessarily mean essential components, and some may be optional components. Accordingly, an embodiment consisting of a subset of components described in an embodiment is also included in the scope of the present disclosure. In addition, embodiments including other elements in addition to the elements described in the various embodiments are included in the scope of the present disclosure.
- the present disclosure relates to encoding and decoding of an image, and terms used in the present disclosure may have a common meaning commonly used in the technical field to which the present disclosure belongs unless newly defined in the present disclosure.
- a “picture” generally refers to a unit representing one image in a specific time period
- a slice/tile is a coding unit constituting a part of a picture
- one picture is one It may be composed of more than one slice/tile.
- a slice/tile may include one or more coding tree units (CTU).
- CTU coding tree units
- one tile may include one or more bricks. The brick may represent a rectangular area of CTU rows in a tile.
- One tile may be divided into a plurality of bricks, and each brick may include one or more CTU rows belonging to the tile.
- pixel or “pel” may mean a minimum unit constituting one picture (or image).
- sample may be used as a term corresponding to a pixel.
- a sample may generally represent a pixel or a value of a pixel, may represent only a pixel/pixel value of a luma component, or may represent only a pixel/pixel value of a chroma component.
- unit may represent a basic unit of image processing.
- the unit may include at least one of a specific area of a picture and information related to the corresponding area.
- the unit may be used interchangeably with terms such as “sample array”, “block”, or “area” depending on the case.
- the MxN block may include samples (or sample arrays) consisting of M columns and N rows, or a set (or array) of transform coefficients.
- current block may mean one of “current coding block”, “current coding unit”, “coding object block”, “decoding object block”, or “processing object block”.
- current block may mean “current prediction block” or “prediction target block”.
- transformation inverse transformation
- quantization inverse quantization
- current block may mean “current transform block” or “transform target block”.
- filtering is performed, “current block” may mean “block to be filtered”.
- current block may mean “a luma block of the current block” unless explicitly stated as a chroma block.
- the “chroma block of the current block” may be expressed by including an explicit description of a chroma block, such as “chroma block” or “current chroma block”.
- FIG. 1 shows a video coding system according to this disclosure.
- a video coding system may include an encoding device 10 and a decoding device 20.
- the encoding device 10 may transmit the encoded video and/or image information or data in a file or streaming format to the decoding device 20 through a digital storage medium or a network.
- the encoding apparatus 10 may include a video source generation unit 11, an encoding unit 12, and a transmission unit 13.
- the decoding apparatus 20 may include a receiving unit 21, a decoding unit 22, and a rendering unit 23.
- the encoder 12 may be referred to as a video/image encoder, and the decoder 22 may be referred to as a video/image decoder.
- the transmission unit 13 may be included in the encoding unit 12.
- the receiving unit 21 may be included in the decoding unit 22.
- the rendering unit 23 may include a display unit, and the display unit may be configured as a separate device or an external component.
- the video source generator 11 may acquire a video/image through a process of capturing, synthesizing, or generating a video/image.
- the video source generator 11 may include a video/image capturing device and/or a video/image generating device.
- the video/image capture device may include, for example, one or more cameras, a video/image archive including previously captured video/images, and the like.
- the video/image generating device may include, for example, a computer, a tablet and a smartphone, and may (electronically) generate a video/image.
- a virtual video/image may be generated through a computer or the like, and in this case, a video/image capturing process may be substituted as a process of generating related data.
- the encoder 12 may encode an input video/image.
- the encoder 12 may perform a series of procedures such as prediction, transformation, and quantization for compression and encoding efficiency.
- the encoder 12 may output encoded data (coded video/image information) in the form of a bitstream.
- the transmission unit 13 may transmit the encoded video/image information or data output in the form of a bitstream to the reception unit 21 of the decoding apparatus 20 through a digital storage medium or a network in a file or streaming form.
- Digital storage media may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD.
- the transmission unit 13 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 receiving unit 21 may extract/receive the bitstream from the storage medium or network and transmit it to the decoding unit 22.
- the decoder 22 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 encoder 12.
- the rendering unit 23 may render the decoded video/image.
- the rendered video/image may be displayed through the display unit.
- FIG. 2 is a diagram schematically illustrating an image encoding apparatus to which an embodiment according to the present disclosure can be applied.
- the image encoding apparatus 100 includes an image segmentation unit 110, a subtraction unit 115, a transformation unit 120, a quantization unit 130, an inverse quantization unit 140, and an inverse transformation unit ( 150), an addition unit 155, a filtering unit 160, a memory 170, an inter prediction unit 180, an intra prediction unit 185, and an entropy encoding unit 190.
- the inter prediction unit 180 and the intra prediction unit 185 may be collectively referred to as a “prediction unit”.
- the transform unit 120, the quantization unit 130, the inverse quantization unit 140, and the inverse transform unit 150 may be included in a residual processing unit.
- the residual processing unit may further include a subtraction unit 115.
- All or at least some of the plurality of constituent units constituting the image encoding apparatus 100 may be implemented as one hardware component (eg, an encoder or a processor) according to embodiments.
- the memory 170 may include a decoded picture buffer (DPB), and may be implemented by a digital storage medium.
- DPB decoded picture buffer
- the image segmentation unit 110 may divide an input image (or picture, frame) input to the image encoding apparatus 100 into one or more processing units.
- the processing unit may be referred to as a coding unit (CU).
- the coding unit is a coding tree unit (CTU) or a largest coding unit (LCU) recursively according to a QT/BT/TT (Quad-tree/binary-tree/ternary-tree) structure ( It can be obtained by dividing recursively.
- 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.
- a quad tree structure may be applied first, and a binary tree structure and/or a ternary tree structure may be applied later.
- the coding procedure according to the present disclosure may be performed based on the final coding unit that is no longer divided.
- the largest coding unit may be directly used as the final coding unit, or a coding unit of a lower depth obtained by dividing the largest coding unit may be used as the final cornet unit.
- the coding procedure may include a procedure such as prediction, transformation, and/or restoration, which will be described later.
- the processing unit of the coding procedure may be a prediction unit (PU) or a transform unit (TU).
- the prediction unit and the transform unit may be divided or partitioned from the final coding unit, respectively.
- the prediction unit may be a unit of sample prediction
- the transform unit may be a unit for inducing a transform coefficient and/or a unit for inducing a residual signal from the transform coefficient.
- the prediction unit (inter prediction unit 180 or intra prediction unit 185) performs prediction on a block to be processed (current block), and generates a predicted block including prediction samples for the current block. Can be generated.
- the prediction unit may determine whether intra prediction or inter prediction is applied in units of a current block or CU.
- the prediction unit may generate various information on prediction of the current block and transmit it to the entropy encoding unit 190.
- the information on prediction may be encoded by the entropy encoding unit 190 and output in the form of a bitstream.
- the intra prediction unit 185 may predict the current block by referring to samples in the current picture.
- the referenced samples may be located in a neighborhood of the current block or may be located away from each other according to an intra prediction mode and/or an intra prediction technique.
- the intra prediction modes may include a plurality of non-directional modes and a plurality of directional modes.
- the non-directional mode may include, for example, a DC mode and a planar mode (Planar mode).
- the directional mode may include, for example, 33 directional prediction modes or 65 directional prediction modes, depending on the degree of detail of the prediction direction. However, this is an example, and more or less directional prediction modes may be used depending on the setting.
- the intra prediction unit 185 may determine a prediction mode applied to the current block by using the prediction mode applied to the neighboring block.
- the inter prediction unit 180 may derive a predicted block for the current block based on a reference block (reference sample array) specified by a motion vector on the reference picture.
- motion information may be predicted in units of blocks, subblocks, or samples based on correlation between motion information between neighboring blocks 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 existing 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 from each other.
- the temporal neighboring block may be referred to by a name such as a collocated reference block and a collocated CU (colCU).
- a reference picture including the temporal neighboring block may be referred to as a collocated picture (colPic).
- the inter prediction unit 180 constructs a motion information candidate list based on neighboring blocks, and provides information indicating which candidate is 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.
- a residual signal may not be transmitted.
- MVP motion vector prediction
- a motion vector of a neighboring block is used as a motion vector predictor, and an indicator for a motion vector difference and a motion vector predictor ( indicator) to signal the motion vector of the current block.
- the motion vector difference may mean a difference between a motion vector of a current block and a motion vector predictor.
- the prediction unit may generate a prediction signal based on various prediction methods and/or prediction techniques to be described later.
- the prediction unit may apply intra prediction or inter prediction for prediction of the current block, and may simultaneously apply intra prediction and inter prediction.
- a prediction method in which intra prediction and inter prediction are applied simultaneously for prediction of the current block may be referred to as combined inter and intra prediction (CIIP).
- the prediction unit may perform intra block copy (IBC) for prediction of the current block.
- the intra block copy may be used for content image/movie coding such as games, such as, for example, screen content coding (SCC).
- IBC is a method of predicting a current block by using a reference block in a current picture at a distance from the current block by a predetermined distance.
- the position of the reference block in the current picture may be encoded as a vector (block vector) corresponding to the predetermined distance.
- IBC basically performs prediction in the current picture, but in that it derives a reference block in the current picture, it may be performed similarly to inter prediction. That is, the IBC may use at least one of the inter prediction techniques described in this disclosure.
- the prediction signal generated through the prediction unit may be used to generate a reconstructed signal or may be used to generate a residual signal.
- the subtraction unit 115 subtracts the prediction signal (predicted block, prediction sample array) output from the prediction unit from the input image signal (original block, original sample array), and subtracts a residual signal (remaining block, residual sample array). ) Can be created.
- the generated residual signal may be transmitted to the converter 120.
- the transform unit 120 may generate transform coefficients by applying a transform technique to the residual signal.
- the transformation technique uses at least one of DCT (Discrete Cosine Transform), DST (Discrete Sine Transform), KLT (Karhunen-Loeve Transform), GBT (Graph-Based Transform), or CNT (Conditionally Non-linear Transform).
- DCT Discrete Cosine Transform
- DST Discrete Sine Transform
- KLT Kerhunen-Loeve Transform
- GBT Graph-Based Transform
- CNT Conditionally Non-linear Transform
- GBT refers to the transformation obtained from this graph when the relationship information between pixels is expressed in a graph.
- CNT refers to a transformation obtained based on generating a prediction signal using all previously reconstructed pixels.
- the conversion process may be applied to a block of pixels having the same size of a square, or may be applied to a block of a variable size other than a square.
- the quantization unit 130 may quantize the transform coefficients and transmit the quantization to the entropy encoding unit 190.
- the entropy encoding unit 190 may encode a quantized signal (information on quantized transform coefficients) and output it as a bitstream. Information about the quantized transform coefficients may be called residual information.
- the quantization unit 130 may rearrange the quantized transform coefficients in a block form into a one-dimensional vector form based on a coefficient scan order, and the quantized transform coefficients in the form of the one-dimensional vector It is also possible to generate information about transform coefficients.
- the entropy encoding unit 190 may perform various encoding methods such as exponential Golomb, context-adaptive variable length coding (CAVLC), context-adaptive binary arithmetic coding (CABAC), and the like.
- the entropy encoding unit 190 may encode together or separately information necessary for video/image restoration (eg, values of syntax elements) in addition to quantized transform coefficients.
- the encoded information (eg, encoded video/video information) may be transmitted or stored in a bitstream form in units of network abstraction layer (NAL) units.
- the video/video information may further include information on 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/video information may further include general constraint information.
- the signaling information, transmitted information, and/or syntax elements mentioned in the present disclosure may be encoded through the above-described encoding procedure and included in the bitstream.
- the bitstream may be transmitted through 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, and SSD.
- a transmission unit (not shown) for transmitting the signal output from the entropy encoding unit 190 and/or a storage unit (not shown) for storing may be provided as an internal/external element of the image encoding apparatus 100, or transmission The unit may be provided as a component of the entropy encoding unit 190.
- the quantized transform coefficients output from the quantization unit 130 may be used to generate a residual signal.
- a residual signal residual block or residual samples
- inverse quantization and inverse transform residual transforms
- the addition unit 155 adds the reconstructed residual signal to the prediction signal output from the inter prediction unit 180 or the intra prediction unit 185 to obtain a reconstructed signal (a reconstructed picture, a reconstructed block, and a reconstructed sample array). Can be generated.
- a reconstructed signal (a reconstructed picture, a reconstructed block, and a reconstructed sample array).
- the predicted block may be used as a reconstructed block.
- the addition unit 155 may be referred to as a restoration unit or a restoration block generation unit.
- the generated reconstructed signal may be used for intra prediction of the next processing target block in the current picture, and may be used for inter prediction of the next picture through filtering as described later.
- the filtering unit 160 may improve subjective/objective image quality by applying filtering to the reconstructed signal.
- the filtering unit 160 may apply various filtering methods to the reconstructed picture to generate a modified reconstructed picture, and the modified reconstructed picture may be converted to the memory 170, specifically, the DPB of the memory 170. Can be saved on.
- the various filtering methods may include, for example, deblocking filtering, sample adaptive offset, adaptive loop filter, bilateral filter, and the like.
- the filtering unit 160 may generate various information about filtering and transmit it to the entropy encoding unit 190 as described later in the description of each filtering method. Information about filtering may be encoded by 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 a reference picture in the inter prediction unit 180.
- the image encoding apparatus 100 may avoid prediction mismatch between the image encoding apparatus 100 and the image decoding apparatus, and may improve encoding efficiency.
- the DPB in the memory 170 may store a reconstructed picture modified to be used as a reference picture in the inter prediction unit 180.
- the memory 170 may store motion information of a block from which motion information in a current picture is derived (or encoded) and/or motion information of blocks in a picture that have already been reconstructed.
- the stored motion information may be transmitted to the inter prediction unit 180 in order to be used as motion information of a spatial neighboring block or motion information of a temporal neighboring block.
- the memory 170 may store reconstructed samples of reconstructed blocks in the current picture, and may be transmitted to the intra prediction unit 185.
- FIG. 3 is a schematic diagram of an image decoding apparatus to which an embodiment according to the present disclosure can be applied.
- the image decoding apparatus 200 includes an entropy decoding unit 210, an inverse quantization unit 220, an inverse transform unit 230, an addition unit 235, a filtering unit 240, and a memory 250. ), an inter prediction unit 260 and an intra prediction unit 265.
- the inter prediction unit 260 and the intra prediction unit 265 may be collectively referred to as a “prediction unit”.
- the inverse quantization unit 220 and the inverse transform unit 230 may be included in the residual processing unit.
- All or at least some of the plurality of constituent units constituting the image decoding apparatus 200 may be implemented as one hardware component (eg, a decoder or a processor) according to embodiments.
- the memory 170 may include a DPB, and may be implemented by a digital storage medium.
- the image decoding apparatus 200 receiving a bitstream including video/image information may reconstruct an image by performing a process corresponding to the process performed by the image encoding apparatus 100 of FIG. 2.
- the image decoding apparatus 200 may perform decoding using a processing unit applied by the image encoding apparatus.
- the processing unit of decoding may be, for example, a coding unit.
- the coding unit may be a coding tree unit or may be obtained by dividing the largest coding unit.
- the reconstructed image signal decoded and output through the image decoding apparatus 200 may be reproduced through a reproducing apparatus (not shown).
- the image decoding apparatus 200 may receive a signal output from the image encoding apparatus of FIG. 2 in the form of a bitstream.
- 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/video information) necessary for image restoration (or picture restoration).
- the video/video information may further include information on 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/video information may further include general constraint information.
- the image decoding apparatus may additionally use information on the parameter set and/or the general restriction information to decode an image.
- the signaling information, received information, and/or syntax elements mentioned in the present disclosure may be obtained from the bitstream by decoding through the decoding procedure.
- the entropy decoding unit 210 decodes information in a bitstream based on a coding method such as exponential Golomb coding, CAVLC, or CABAC, and a value of a syntax element required for image restoration, a quantized value of a transform coefficient related to a residual. Can be printed.
- the CABAC entropy decoding method receives a bin corresponding to each syntax element in a bitstream, and includes information on a syntax element to be decoded, information on a neighboring block and decoding information on a block to be decoded, or information on a symbol/bin decoded in a previous step.
- the context model is determined using the context model, and the probability of occurrence of the bin is predicted according to the determined context model, and arithmetic decoding of the bin is performed to generate a symbol corresponding to the value of each syntax element.
- the CABAC entropy decoding method may update the context model using information of the decoded symbol/bin for the context model of the next symbol/bin after the context model is determined.
- information about prediction is provided to the prediction unit (inter prediction unit 260 and intra prediction unit 265), and the register on which entropy decoding is performed by the entropy decoding unit 210
- the dual value that is, quantized transform coefficients and related parameter information may be input to the inverse quantization unit 220.
- information about filtering among information decoded by the entropy decoding unit 210 may be provided to the filtering unit 240.
- a receiving unit for receiving a signal output from the image encoding device may be additionally provided as an inner/outer element of the image decoding device 200, or the receiving unit is provided as a component of the entropy decoding unit 210 It could be.
- the video decoding apparatus may include an information decoder (video/video/picture information decoder) and/or a sample decoder (video/video/picture sample decoder).
- the information decoder may include an entropy decoding unit 210, and the sample decoder includes an inverse quantization unit 220, an inverse transform unit 230, an addition unit 235, a filtering unit 240, a memory 250, It may include at least one of the inter prediction unit 260 and the intra prediction unit 265.
- the inverse quantization unit 220 may inverse quantize the quantized transform coefficients and output transform coefficients.
- the inverse quantization unit 220 may rearrange the quantized transform coefficients in a two-dimensional block shape. In this case, the rearrangement may be performed based on a coefficient scan order performed by the image encoding apparatus.
- the inverse quantization unit 220 may perform inverse quantization on quantized transform coefficients using a quantization parameter (eg, quantization step size information) and obtain transform coefficients.
- a quantization parameter eg, quantization step size information
- the inverse transform unit 230 may inverse transform 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 prediction information output from the entropy decoding unit 210, and determine a specific intra/inter prediction mode (prediction technique). I can.
- the prediction unit can generate the prediction signal based on various prediction methods (techniques) described later.
- the intra prediction unit 265 may predict the current block by referring to samples in the current picture.
- the description of the intra prediction unit 185 may be equally applied to the intra prediction unit 265.
- the inter prediction unit 260 may derive a predicted block for the current block based on a reference block (reference sample array) specified by a motion vector on the reference picture.
- motion information may be predicted in units of blocks, subblocks, or samples based on correlation between motion information between neighboring blocks 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 existing 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 (techniques), and the information on prediction may include information indicating a mode (technique) of inter prediction for the current block.
- the addition unit 235 is reconstructed by adding the obtained residual signal to the prediction signal (predicted block, prediction sample array) output from the prediction unit (including the inter prediction unit 260 and/or the intra prediction unit 265).
- a signal (restored picture, reconstructed block, reconstructed sample array) can be generated.
- the predicted block may be used as a reconstructed block.
- the description of the addition unit 155 may be equally applied to the addition unit 235.
- the addition unit 235 may be referred to as a restoration unit or a restoration block generation unit.
- the generated reconstructed signal may be used for intra prediction of the next processing target block in the current picture, and may be used for inter prediction of the next picture through filtering as described later.
- the filtering unit 240 may improve subjective/objective image quality by applying filtering to the reconstructed signal.
- the filtering unit 240 may apply various filtering methods to the reconstructed picture to generate a modified reconstructed picture, and the modified reconstructed picture may be converted to the memory 250, specifically, the DPB of the memory 250. Can be saved on.
- the various filtering methods may include, for example, deblocking filtering, sample adaptive offset, adaptive loop filter, bilateral filter, and the like.
- the reconstructed picture (modified) stored in the DPB of the memory 250 may be used as a reference picture in the inter prediction unit 260.
- the memory 250 may store motion information of a block from which motion information in a current picture is derived (or decoded) and/or motion information of blocks in a picture that have already been reconstructed.
- the stored motion information may be transmitted to the inter prediction unit 260 to be used as motion information of a spatial neighboring block or motion information of a temporal neighboring block.
- the memory 250 may store reconstructed samples of reconstructed blocks in the current picture, and may be transmitted to the intra prediction unit 265.
- embodiments described in the filtering unit 160, the inter prediction unit 180, and the intra prediction unit 185 of the image encoding apparatus 100 are respectively the filtering unit 240 of the image decoding apparatus 200, The same or corresponding to the inter prediction unit 260 and the intra prediction unit 265 may be applied.
- the video/image coding method according to the present disclosure may be performed based on the following image segmentation structure. Specifically, procedures such as prediction, residual processing ((inverse) transformation, (inverse) quantization, etc.), syntax element coding, filtering, etc., which will be described later, are CTU, CU (and/or TU, PU) can be performed.
- the image may be divided in block units, and the block division procedure may be performed by the image dividing unit 110 of the above-described encoding apparatus.
- Split-related information may be encoded by the entropy encoding unit 190 and transmitted to a decoding apparatus in the form of a bitstream.
- the entropy decoding unit 210 of the decoding apparatus derives a block division structure of the current picture based on the division-related information obtained from the bitstream, and based on this, a series of procedures for decoding an image (ex. prediction, residual). Processing, block/picture restoration, in-loop filtering, etc.) can be performed.
- Pictures can be divided into a sequence of coding tree units (CTUs). 4 shows an example in which a picture is divided into CTUs.
- the CTU may correspond to a coding tree block (CTB).
- CTB coding tree block
- the CTU may include a coding tree block of luma samples and two coding tree blocks of corresponding chroma samples.
- the CTU may include an NxN block of luma samples and two corresponding blocks of chroma samples.
- the coding unit is obtained by recursively dividing a coding tree unit (CTU) or a maximum coding unit (LCU) according to a QT/BT/TT (Quad-tree/binary-tree/ternary-tree) structure.
- CTU coding tree unit
- LCU maximum coding unit
- QT/BT/TT Quad-tree/binary-tree/ternary-tree
- the CTU may be first divided into a quadtree structure. Thereafter, leaf nodes of a quadtree structure may be further divided by a multitype tree structure.
- the division according to the quadtree means division in which the current CU (or CTU) is divided into four. By partitioning according to the quadtree, the current CU can be divided into four CUs having the same width and the same height.
- the current CU corresponds to a leaf node of the quadtree structure.
- the CU corresponding to the leaf node of the quadtree structure is no longer divided and may be used as the above-described final coding unit.
- a CU corresponding to a leaf node of a quadtree structure may be further divided by a multitype tree structure.
- the division according to the multi-type tree structure may include two divisions according to the binary tree structure and two divisions according to the ternary tree structure.
- the two divisions according to the binary tree structure may include vertical binary splitting (SPLIT_BT_VER) and horizontal binary splitting (SPLIT_BT_HOR).
- the vertical binary division (SPLIT_BT_VER) means division in which the current CU is divided into two in the vertical direction. As shown in FIG. 4, two CUs having a height equal to the height of the current CU and a width of half the width of the current CU may be generated by vertical binary division.
- the horizontal binary division means division in which the current CU is divided into two in the horizontal direction. As shown in FIG. 5, two CUs having a height of half the height of the current CU and a width equal to the width of the current CU may be generated by horizontal binary division.
- the two divisions according to the ternary tree structure may include vertical ternary splitting (SPLIT_TT_VER) and horizontal ternary splitting (hotizontal ternary splitting, SPLIT_TT_HOR).
- the vertical ternary division (SPLIT_TT_VER) divides the current CU in the vertical direction at a ratio of 1:2:1. As shown in FIG. 5, by vertical ternary division, two CUs having a height equal to the height of the current CU and a width of 1/4 of the width of the current CU, and a current CU having a height equal to the height of the current CU A CU with a width of half the width of can be created.
- the horizontal ternary division divides the current CU in the horizontal direction at a ratio of 1:2:1. As shown in FIG. 4, by horizontal ternary division, two CUs having a height of 1/4 of the height of the current CU and having the same width as the width of the current CU, and a height of half the height of the current CU, and the current One CU can be created with a width equal to the width of the CU.
- FIG. 6 is a diagram illustrating a signaling mechanism of block division information in a quadtree with nested multi-type tree structure according to the present disclosure.
- the CTU is treated as a root node of a quadtree, and the CTU is first divided into a quadtree structure.
- Information eg, qt_split_flag
- qt_split_flag a first value (eg, “1”)
- the current CU may be quadtree split.
- qt_split_flag is a second value (eg, "0")
- the current CU is not divided into a quadtree, but becomes a leaf node (QT_leaf_node) of the quadtree.
- the leaf nodes of each quadtree can then be further divided into a multi-type tree structure. That is, a leaf node of a quad tree may be a node (MTT_node) of a multi-type tree.
- a first flag (ex. mtt_split_cu_flag) may be signaled to indicate whether the current node is additionally divided.
- a second flag (e.g. mtt_split_cu_verticla_flag) may be signaled to indicate the splitting direction.
- the division direction may be a vertical direction
- the second flag is 0, the division direction may be a horizontal direction.
- a third flag (eg, mtt_split_cu_binary_flag) may be signaled to indicate whether the division type is a binary division type or a ternary division type.
- the division type may be a binary division type
- the third flag when the third flag is 0, the division type may be a ternary division type.
- Nodes of a multitype tree obtained by binary division or ternary division may be further partitioned into a multitype tree structure.
- nodes of a multitype tree cannot be partitioned into a quadtree structure.
- the first flag is 0, the corresponding node of the multi-type tree is no longer divided and becomes a leaf node (MTT_leaf_node) of the multi-type tree.
- the CU corresponding to the leaf node of the multitype tree may be used as the above-described final coding unit.
- a multi-type tree splitting mode (MttSplitMode) of the CU may be derived as shown in Table 1.
- the multitree partitioning mode may be abbreviated as a multitree partitioning type or a partitioning type.
- a bold block edge 710 represents a quadtree division
- the remaining edges 720 represent a multi-type tree division.
- the CU may correspond to a coding block (CB).
- a CU may include a coding block of luma samples and two coding blocks of chroma samples corresponding to the luma samples.
- the chroma component (sample) CB or TB size is determined by the luma component (sample) according to the component ratio according to the color format (chroma format, ex.
- the chroma component CB/TB size may be set equal to the luma component CB/TB size.
- the width of the chroma component CB/TB may be set to half the width of the luma component CB/TB, and the height of the chroma component CB/TB may be set to the height of the luma component CB/TB.
- the width of the chroma component CB/TB may be set to half the width of the luma component CB/TB, and the height of the chroma component CB/TB may be set to half the height of the luma component CB/TB.
- the size of the CU when the size of the CTU is 128 based on the luma sample unit, the size of the CU may have a size ranging from 128 x 128 to 4 x 4, which is the same size as the CTU.
- the chroma CB size in the case of a 4:2:0 color format (or chroma format), the chroma CB size may have a size ranging from 64x64 to 2x2.
- the CU size and the TU size may be the same.
- a plurality of TUs may exist in the CU region.
- the TU size may generally represent a luma component (sample) TB (Transform Block) size.
- the TU size may be derived based on a preset maximum allowable TB size (maxTbSize). For example, when the CU size is larger than the maxTbSize, a plurality of TUs (TB) having the maxTbSize may be derived from the CU, and transformation/inverse transformation may be performed in units of the TU (TB). For example, the maximum allowable luma TB size may be 64x64, and the maximum allowable chroma TB size may be 32x32. If the width or height of the CB divided according to the tree structure is larger than the maximum transform width or height, the CB may be automatically (or implicitly) divided until the TB size limit in the horizontal and vertical directions is satisfied.
- the intra prediction mode/type is derived in units of the CU (or CB), and procedures for deriving neighboring reference samples and generating prediction samples may be performed in units of TU (or TB).
- the intra prediction mode/type is derived in units of the CU (or CB)
- procedures for deriving neighboring reference samples and generating prediction samples may be performed in units of TU (or TB).
- one or a plurality of TUs (or TBs) may exist in one CU (or CB) region, and in this case, the plurality of TUs (or TBs) may share the same intra prediction mode/type.
- the following parameters may be signaled from the encoding device to the decoding device as SPS syntax elements.
- CTU size a parameter indicating the size of the root node of a quadtree tree
- MinQTSize a parameter indicating the minimum usable size of a quadtree leaf node
- MaxBTSize a parameter indicating the maximum usable size of a binary tree root node
- maximum of a ternary tree root node a parameter indicating the maximum usable size of a binary tree root node.
- MaxTTSize a parameter representing the usable size
- MaxMttDepth a parameter representing the maximum allowed hierarchy depth of a multitype tree divided from a quadtree leaf node
- MinBtSize a parameter representing the minimum usable leaf node size of a binary tree
- At least one of MinTtSize which is a parameter indicating the minimum available leaf node size of the retree, may be signaled.
- the CTU size may be set to a 128x128 luma block and two 64x64 chroma blocks corresponding to the luma block.
- MinQTSize is set to 16x16
- MaxBtSize is set to 128x1208
- MaxTtSzie is set to 64x64
- MinBtSize and MinTtSize are set to 4x4
- MaxMttDepth may be set to 4.
- Quart tree partitioning can be applied to CTU to create quadtree leaf nodes.
- the quadtree leaf node may be referred to as a leaf QT node.
- Quadtree leaf nodes may have a size of 128x128 (e.g.
- the leaf QT node is 128x128, it may not be additionally divided into a binary tree/ternary tree. This is because in this case, even if it is divided, it exceeds MaxBtsize and MaxTtszie (i.e. 64x64). In other cases, the leaf QT node can be further divided into a multi-type tree. Therefore, the leaf QT node is a root node for a multi-type tree, and the leaf QT node may have a multi-type tree depth (mttDepth) of 0. If the multi-type tree depth reaches MaxMttdepth (ex. 4), additional partitioning may not be considered any more.
- mttDepth multi-type tree depth
- the encoding apparatus may omit signaling of the division information. In this case, the decoding apparatus may derive the segmentation information with a predetermined value.
- one CTU may include a coding block of luma samples (hereinafter, referred to as a “luma block”) and two coding blocks of chroma samples corresponding thereto (hereinafter, referred to as a “chroma block”).
- the above-described coding tree scheme may be applied equally to the luma block and the chroma block of the current CU, or may be applied separately.
- a luma block and a chroma block in one CTU may be divided into the same block tree structure, and the tree structure in this case may be represented as a single tree (SINGLE_TREE).
- a luma block and a chroma block in one CTU may be divided into individual block tree structures, and the tree structure in this case may be represented as a dual tree (DUAL_TREE). That is, when the CTU is divided into a dual tree, a block tree structure for a luma block and a block tree structure for a chroma block may exist separately.
- the block tree structure for the luma block may be referred to as a dual tree luma (DUAL_TREE_LUMA)
- the block tree structure for the chroma block may be referred to as a dual tree chroma (DUAL_TREE_CHROMA).
- luma blocks and chroma blocks in one CTU may be limited to have the same coding tree structure.
- luma blocks and chroma blocks may have separate block tree structures from each other. If an individual block tree structure is applied, a luma coding tree block (CTB) may be divided into CUs based on a specific coding tree structure, and the chroma CTB may be divided into chroma CUs based on a different coding tree structure.
- CTB luma coding tree block
- a CU in an I slice/tile group to which an individual block tree structure is applied is composed of a coding block of a luma component or a coding block of two chroma components, and a CU of a P or B slice/tile group has three color components (luma component And two chroma components).
- the structure in which the CU is divided is not limited thereto.
- the BT structure and the TT structure can be interpreted as a concept included in the Multiple Partitioning Tree (MPT) structure, and the CU can be interpreted as being divided through the QT structure and the MPT structure.
- MPT Multiple Partitioning Tree
- a syntax element e.g., MPT_split_type
- MPT_split_mode a syntax element including information on which direction of splitting between horizontal and horizontal.
- the CU may be divided in a different way from the QT structure, the BT structure, or the TT structure. That is, according to the QT structure, the CU of the lower depth is divided into 1/4 size of the CU of the upper depth, or the CU of the lower depth is divided into 1/2 of the CU of the upper depth according to the BT structure, or according to the TT structure. Unlike CUs of lower depth are divided into 1/4 or 1/2 of CUs of higher depth, CUs of lower depth are 1/5, 1/3, 3/8, 3 of CUs of higher depth depending on the case. It may be divided into /5, 2/3, or 5/8 size, and the method of partitioning the CU is not limited thereto.
- the quadtree coding block structure accompanying the multi-type tree can provide a very flexible block division structure.
- different partitioning patterns may potentially lead to the same coding block structure result in some cases.
- the encoding device and the decoding device can reduce the amount of data of the split information by limiting the occurrence of such redundant split patterns.
- an image processing unit may have a hierarchical structure.
- One picture may be divided into one or more tiles, bricks, slices, and/or tile groups.
- One slice may include one or more bricks.
- One brick may contain one or more CTU rows in a tile.
- a slice may include an integer number of bricks of a picture.
- One tile group may include one or more tiles.
- One tile may contain more than one CTU.
- the CTU may be divided into one or more CUs.
- a tile may be a rectangular area composed of a specific tile row and a specific tile column composed of a plurality of CTUs in a picture.
- the tile group may include an integer number of tiles according to a tile raster scan in a picture.
- the slice header may carry information/parameters applicable to the corresponding slice (blocks in the slice).
- the encoding/decoding procedure for the tile, slice, brick, and/or tile group may be processed in parallel.
- the names or concepts of slices or tile groups may be used interchangeably. That is, the tile group header may be referred to as a slice header.
- the slice may have one of slice types including intra (I) slice, predictive (P) slice, and bi-predictive (B) slice.
- I slice intra (I) slice, predictive (P) slice, and bi-predictive (B) slice.
- I slice intra (I) slice, predictive (P) slice, and bi-predictive (B) slice.
- I slice intra (I) slice
- P slice predictive slice
- B slice bi-predictive
- intra prediction or inter prediction may be used, and when inter prediction is used, only uni prediction may be used.
- intra prediction or inter prediction may be used, and when inter prediction is used, up to bi prediction may be used.
- the encoding apparatus may determine a tile/tile group, a brick, a slice, and a maximum and minimum coding unit size according to a characteristic (eg, resolution) of a video image or in consideration of coding efficiency or parallel processing. In addition, information about this or information that can induce it may be included in the bitstream.
- a characteristic eg, resolution
- information about this or information that can induce it may be included in the bitstream.
- the decoding apparatus may obtain information indicating whether a tile/tile group, a brick, a slice, and a CTU within a tile of the current picture is divided into a plurality of coding units.
- the encoding device and the decoding device may increase encoding efficiency by signaling such information only under specific conditions.
- the slice header may include information/parameters commonly applicable to the slice.
- APS APS syntax
- PPS PPS syntax
- SPS SPS syntax
- VPS VPS syntax
- DPS DPS syntax
- CVS coded video sequence
- information on the division and configuration of the tile/tile group/brick/slice may be configured at the encoding stage through the higher level syntax and transmitted to the decoding apparatus in the form of a bitstream.
- the quantization unit of the encoding device can derive quantized transform coefficients by applying quantization to the transform coefficients, and the inverse quantization unit of the encoding device or the inverse quantization unit of the decoding device applies inverse quantization to the quantized transform coefficients.
- transform coefficients can be derived.
- the quantization rate can be changed, and the compression rate can be adjusted using the changed quantization rate.
- a quantization parameter can be used instead of using a quantization rate directly in consideration of complexity.
- quantization parameters of integer values from 0 to 63 may be used, and each quantization parameter value may correspond to an actual quantization rate.
- the quantization parameter QP Y for the luma component (luma sample) and the quantization parameter QP C for the chroma component (chroma sample) may be set differently.
- the quantization process takes a transform coefficient C as an input, divides it by a quantization rate Qstep, and obtains a quantized transform coefficient C ⁇ based on this.
- a quantization rate is multiplied by a scale in consideration of computational complexity to form an integer, and a shift operation may be performed by a value corresponding to the scale value.
- a quantization scale may be derived based on the product of the quantization rate and the scale value. That is, the quantization scale may be derived according to the QP.
- a quantized transform coefficient C′ may be derived based on the quantization scale.
- the inverse quantization process is an inverse process of the quantization process.
- a reconstructed transform coefficient (C ⁇ ) By multiplying the quantized transform coefficient (C ⁇ ) by the quantization rate (Qstep), a reconstructed transform coefficient (C ⁇ ) can be obtained based on this.
- a level scale may be derived according to the quantization parameter, and a reconstructed transform coefficient (C ⁇ ) is derived based on the level scale applied to the quantized transform coefficient (C ⁇ ). can do.
- the restored transform coefficient C ⁇ may be slightly different from the original transform coefficient C due to a loss in the transform and/or quantization process. Accordingly, in the encoding device, inverse quantization can be performed in the same manner as in the decoding device.
- an adaptive frequency weighting quantization technique that adjusts the quantization intensity according to the frequency may be applied.
- the adaptive frequency-weighted quantization technique is a method of applying different quantization strengths for each frequency.
- a quantization intensity for each frequency may be differently applied using a predefined quantization scaling matrix. That is, the above-described quantization/dequantization process may be further performed based on the quantization scaling matrix. For example, in order to generate the size of the current block and/or the residual signal of the current block, different quantization scaling metrics may be used depending on whether the prediction mode applied to the current block is inter prediction or intra prediction.
- the quantization scaling matrix may be referred to as a quantization matrix or a scaling matrix.
- the quantization scaling matrix may be predefined.
- quantization scale information for each frequency of the quantization scaling matrix may be configured/coded by an encoding device and signaled to a decoding device.
- the quantization scale information for each frequency may be referred to as quantization scaling information.
- the quantization scale information for each frequency may include scaling list data (scaling_list_data).
- scaling_list_data The (modified) quantization scaling matrix may be derived based on the scaling list data.
- the quantization scale information for each frequency may include present flag information indicating whether the scaling list data is present or not.
- the scaling list data is signaled at a higher level (ex. SPS)
- information indicating whether the scaling list data is modified at a lower level eg PPS or tile group header, etc.
- the encoding apparatus may derive a residual block (residual samples) based on a block (prediction samples) predicted through intra/inter/IBC prediction, etc., and the derived residual samples It is possible to derive quantized transform coefficients by applying transform and quantization.
- Information on the quantized transform coefficients may be included in the residual coding syntax, encoded, and then output in the form of a bitstream.
- the decoding apparatus may obtain information (residual information) on the quantized transform coefficients from the bitstream, and decode the quantized transform coefficients to derive the quantized transform coefficients.
- the decoding apparatus may derive residual samples through inverse quantization/inverse transformation based on the quantized transform coefficients.
- the transform coefficient may be referred to as a coefficient or a residual coefficient, or may still be referred to as a transform coefficient for uniformity of expression. Whether the transform/inverse transform is omitted may be signaled based on a transform skip flag (e.g. transform_skip_flag).
- a transform skip flag e.g. transform_skip_flag
- the transform/inverse transform may be performed based on transform kernel(s). For example, a multiple transform selection (MTS) scheme for performing transform/inverse transform may be applied. In this case, some of a plurality of transform kernel sets may be selected and applied to the current block.
- the transformation kernel can be referred to in various terms such as transformation matrix and transformation type.
- the transform kernel set may represent a combination of a vertical transform kernel (vertical transform kernel) and a horizontal transform kernel (horizontal transform kernel).
- the transformation/inverse transformation may be performed in units of CU or TU. That is, the transform/inverse transform may be applied to residual samples in a CU or residual samples in a TU.
- the CU size and the TU size may be the same, or a plurality of TUs may exist in the CU region.
- the CU size may generally indicate the luma component (sample) CB size.
- the TU size may generally refer to the luma component (sample) TB size.
- the chroma component (sample) CB or TB size is the luma component (sample) CB or TB according to the component ratio according to the color format (chroma format, ex.
- the TU size may be derived based on maxTbSize. For example, when the CU size is larger than the maxTbSize, a plurality of TUs (TB) of the maxTbSize may be derived from the CU, and transformation/inverse transformation may be performed in units of the TU (TB).
- the maxTbSize may be considered to determine whether to apply various intra prediction types such as ISP.
- the information on the maxTbSize may be determined in advance, or may be generated and encoded by an encoding device and signaled to an encoding device.
- some or all of the video/video information may be entropy-encoded by the entropy encoding unit 190, and some or all of the video/video information described with reference to FIG. 3 is an entropy decoding unit. It can be entropy decoded by (310).
- the video/video information may be encoded/decoded in units of syntax elements.
- that information is encoded/decoded may include encoding/decoding by the method described in this paragraph.
- each binary number 0 or 1 constituting the binary value may be referred to as a bin.
- each of 1, 1, and 0 may be referred to as one bin.
- the bin(s) for one syntax element may represent a value of a corresponding syntax element.
- the binarized bins can be input into a regular coding engine or a bypass coding engine.
- the regular coding engine may allocate a context model that reflects a probability value to the corresponding bin, and encode the corresponding bin based on the allocated context model.
- the probability model for the corresponding bin can be updated. Bins coded in this way may be referred to as context-coded bins.
- the bypass coding engine may omit a procedure for estimating a probability for an input bin and a procedure for updating a probability model applied to a corresponding bin after coding.
- the coding speed can be improved by coding the input bin by applying a uniform probability distribution (ex.
- Bins coded in this way may be referred to as bypass bins.
- the context model may be allocated and updated for each bin to be context coded (regularly coded), and the context model may be indicated based on ctxidx or ctxInc.
- ctxidx can be derived based on ctxInc.
- a context index (ctxidx) indicating a context model for each of the regularly coded bins may be derived as a sum of a context index increment (ctxInc) and a context index offset (ctxIdxOffset).
- the ctxInc may be derived differently for each bin.
- the ctxIdxOffset may be expressed as the lowest value of the ctxIdx.
- the minimum value of ctxIdx may be referred to as an initial value (initValue) of ctxIdx.
- the ctxIdxOffset is a value generally used to distinguish context models for other syntax elements, and a context model for one syntax element may be classified/derived based on ctxinc.
- Entropy decoding may perform the same process as entropy encoding in reverse order.
- the entropy coding described above may be performed, for example, as shown in FIGS. 9 and 10.
- an encoding apparatus entropy encoding unit
- the image/video information may include partitioning related information, prediction related information (eg inter/intra prediction classification information, intra prediction mode information, inter prediction mode information, etc.), residual information, in-loop filtering related information, and the like, Or it may include various syntax elements related thereto.
- the entropy coding may be performed in units of syntax elements. Steps S910 to S920 of FIG. 9 may be performed by the entropy encoding unit 190 of the encoding apparatus of FIG. 2 described above.
- the encoding apparatus may perform binarization on the target syntax element (S910).
- the binarization may be based on various binarization methods such as a Truncated Rice binarization process and a fixed-length binarization process, and a binarization method for a target syntax element may be predefined.
- the binarization procedure may be performed by the binarization unit 191 in the entropy encoding unit 190.
- the encoding apparatus may perform entropy encoding on the target syntax element (S920).
- the encoding apparatus may encode the empty string of the target syntax element based on regular coding (context based) or bypass coding based on entropy coding techniques such as context-adaptive arithmetic coding (CABAC) or context-adaptive variable length coding (CAVLC).
- CABAC context-adaptive arithmetic coding
- CAVLC context-adaptive variable length coding
- the entropy encoding procedure may be performed by the entropy encoding processing unit 192 in the entropy encoding unit 190.
- the bitstream can be delivered to a decoding device through a (digital) storage medium or a network.
- a decoding apparatus may decode encoded image/video information.
- the image/video information may include partitioning-related information, prediction-related information (ex.inter/intra prediction classification information, intra prediction mode information, inter prediction mode information, etc.), residual information, in-loop filtering-related information, and the like. , Or various syntax elements related thereto.
- the entropy coding may be performed in units of syntax elements. S1110 to S1120 may be performed by the entropy decoding unit 210 of the decoding apparatus of FIG. 3 described above.
- the decoding apparatus may perform binarization on the target syntax element (S1110).
- the binarization may be based on various binarization methods such as a Truncated Rice binarization process and a fixed-length binarization process, and a binarization method for a target syntax element may be predefined.
- the decoding apparatus may derive available empty strings (empty string candidates) for available values of a target syntax element through the binarization procedure.
- the binarization procedure may be performed by the binarization unit 211 in the entropy decoding unit 210.
- the decoding apparatus may perform entropy decoding on the target syntax element (S1120).
- the decoding apparatus may sequentially decode and parse each bin for the target syntax element from the input bit(s) in the bitstream, and compare the derived bin string with the available bin strings for the corresponding syntax element. If the derived empty string is the same as one of the available empty strings, a value corresponding to the corresponding empty string may be derived as a value of the corresponding syntax element. If not, it is possible to perform the above-described procedure again after further parsing the next bit in the bitstream. Through this process, the corresponding information can be signaled using variable length bits without using a start bit or an end bit for specific information (specific syntax element) in the bitstream. Through this, relatively fewer bits can be allocated to a low value, and overall coding efficiency can be improved.
- the decoding apparatus may perform context-based or bypass-based decoding of each bin in the bin string from a bitstream based on an entropy coding technique such as CABAC or CAVLC.
- the entropy decoding procedure may be performed by the entropy decoding processing unit 212 in the entropy decoding unit 210.
- the bitstream may include various information for video/video decoding.
- the bitstream can be delivered to a decoding device through a (digital) storage medium or a network.
- a table including syntax elements may be used to indicate signaling of information from an encoding device to a decoding device.
- the order of syntax elements in a table including the syntax elements used in this document may indicate a parsing order of syntax elements from a bitstream.
- the encoding apparatus may construct and encode a syntax table so that the syntax elements can be parsed by the decoding apparatus in a parsing order, and the decoding apparatus parses and decodes the syntax elements of the corresponding syntax table from the bitstream according to the parsing order, You can get the value.
- Video/video coding procedure general
- pictures constituting the video/video may be encoded/decoded according to a series of decoding orders.
- a picture order corresponding to an output order of a decoded picture may be set differently from the decoding order, and based on this, not only forward prediction but also backward prediction may be performed during inter prediction.
- S1310 may be performed by the entropy decoding unit 210 of the decoding apparatus described above in FIG. 3, and S1320 may be performed by a prediction unit including the intra prediction unit 265 and the inter prediction unit 260.
- S1330 may be performed in the residual processing unit including the inverse quantization unit 220 and the inverse transform unit 230
- S1340 may be performed in the addition unit 235
- S1350 is performed in the filtering unit 240.
- I can.
- S1310 may include the information decoding procedure described in this document
- S1320 may include the inter/intra prediction procedure described in this document
- S1330 may include the residual processing procedure described in this document
- S1340 may include the block/picture restoration procedure described in this document
- S1350 may include the in-loop filtering procedure described in this document.
- the picture decoding procedure is schematically a procedure for obtaining image/video information (through decoding) from a bitstream (S1310), a picture restoration procedure (S1320 to S1340), and reconstructed as shown in the description of FIG.
- An in-loop filtering procedure for a picture (S1350) may be included.
- the picture restoration procedure is based on prediction samples and residual samples obtained through the process of inter/intra prediction (S1320) and residual processing (S1330, inverse quantization and inverse transformation of quantized transform coefficients) described in this document. Can be done.
- a modified reconstructed picture may be generated through an in-loop filtering procedure for a reconstructed picture generated through the picture restoration procedure, and the modified reconstructed picture may be output as a decoded picture. It may be stored in the decoded picture buffer or memory 250 and used as a reference picture in an inter prediction procedure when decoding a picture later. In some cases, the in-loop filtering procedure may be omitted, and in this case, the reconstructed picture may be output as a decoded picture, and is also stored in the decoded picture buffer or memory 250 of the decoding apparatus, It can be used as a reference picture in the prediction procedure.
- the in-loop filtering procedure includes a deblocking filtering procedure, a sample adaptive offset (SAO) procedure, an adaptive loop filter (ALF) procedure, and/or a bi-lateral filter procedure, as described above. May be, and some or all of them may be omitted.
- one or some of the deblocking filtering procedure, sample adaptive offset (SAO) procedure, adaptive loop filter (ALF) procedure, and bi-lateral filter procedure may be sequentially applied, or all of them may be sequentially applied. It can also be applied as.
- the SAO procedure may be performed.
- the ALF procedure may be performed. This can be similarly performed in the encoding device.
- S1410 may be performed by a prediction unit including the intra prediction unit 185 or the inter prediction unit 180 of the encoding apparatus described above in FIG. 2, and S1420 is the transform unit 120 and/or the quantization unit ( 130), and S1430 may be performed by the entropy encoding unit 190.
- S1410 may include the inter/intra prediction procedure described in this document
- S1420 may include the residual processing procedure described in this document
- S1430 may include the information encoding procedure described in this document. .
- the picture encoding procedure is a procedure of encoding information (ex. prediction information, residual information, partitioning information, etc.) for picture restoration and outputting it in the form of a bitstream, as shown in the description of FIG. 2.
- a procedure for generating a reconstructed picture for the current picture and a procedure for applying in-loop filtering to the reconstructed picture may be included.
- the encoding apparatus may derive (modified) residual samples from the quantized transform coefficients through the inverse quantization unit 140 and the inverse transform unit 150, and predictive samples that are outputs of S1410 and the (modified) residual samples.
- a reconstructed picture may be generated based on samples.
- the reconstructed picture generated in this way may be the same as the reconstructed picture generated by the above-described decoding apparatus.
- a modified reconstructed picture may be generated through an in-loop filtering procedure for the reconstructed picture, which may be stored in a decoded picture buffer or memory 170. It can be used as a reference picture in the prediction procedure. As described above, in some cases, some or all of the in-loop filtering procedure may be omitted.
- (in-loop) filtering-related information may be encoded by the entropy encoding unit 190 and output in the form of a bitstream, and the decoding apparatus encodes based on the filtering-related information.
- the in-loop filtering procedure can be performed in the same way as the device.
- the encoding device and the decoding device can derive the same prediction result, increase the reliability of picture coding, and reduce the amount of data to be transmitted for picture coding. Can be reduced.
- a reconstructed block may be generated based on intra prediction/inter prediction for each block, and a reconstructed picture including the reconstructed blocks may be generated.
- the current picture/slice/tile group is an I picture/slice/tile group
- blocks included in the current picture/slice/tile group may be reconstructed based only on intra prediction.
- the current picture/slice/tile group is a P or B picture/slice/tile group
- blocks included in the current picture/slice/tile group may be reconstructed based on intra prediction or inter prediction.
- inter prediction may be applied to some blocks in the current picture/slice/tile group, and intra prediction may be applied to the remaining some blocks.
- the color component of a picture may include a luma component and a chroma component, and unless explicitly limited in this document, the methods and embodiments proposed in this document may be applied to the luma component and the chroma component.
- the coded video/image according to this document may be processed according to, for example, a coding layer and structure to be described later.
- the coded image is a video coding layer (VCL) that deals with the decoding process of the image and itself, a subsystem that transmits and stores encoded information, and exists between the VCL and the subsystem and is responsible for network adaptation. It can be classified into a network abstraction layer (NAL).
- VCL video coding layer
- NAL network abstraction layer
- VCL data including compressed video data is generated, or a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (Video Parameter Set: A parameter set including information such as VPS) or a Supplemental Enhancement Information (SEI) message additionally required for a video decoding process may be generated.
- PPS picture parameter set
- SPS sequence parameter set
- SEI Supplemental Enhancement Information
- a NAL unit may be generated by adding header information (NAL unit header) to a Raw Byte Sequence Payload (RBSP) generated in VCL.
- RBSP refers to slice data, parameter set, SEI message, etc. generated in the VCL.
- the NAL unit header may include NAL unit type information specified according to RBSP data included in the corresponding NAL unit.
- the NAL unit may be divided into a VCL NAL unit and a Non-VCL NAL unit according to the RBSP generated from the VCL.
- the VCL NAL unit may mean a NAL unit including information (slice data) on an image
- the Non-VCL NAL unit is a NAL unit including information (parameter set or SEI message) necessary for decoding an image.
- VCL NAL unit and Non-VCL NAL unit may be transmitted through a network by attaching header information according to the data standard of the sub-system.
- the NAL unit may be transformed into a data format of a predetermined standard such as an H.266/VVC file format, Real-time Transport Protocol (RTP), Transport Stream (TS), and the like and transmitted through various networks.
- RTP Real-time Transport Protocol
- TS Transport Stream
- the NAL unit type may be specified according to the RBSP data structure included in the NAL unit, and information on the NAL unit type may be stored in the NAL unit header and signaled.
- the NAL unit may be largely classified into a VCL NAL unit type and a Non-VCL NAL unit type.
- the VCL NAL unit type may be classified according to the nature and type of a picture included in the VCL NAL unit, and the non-VCL NAL unit type may be classified according to the type of a parameter set.
- NAL unit type specified according to the type of a parameter set included in the Non-VCL NAL unit type, etc. is listed.
- NAL unit Type for NAL unit including APS
- NAL unit A type for a NAL unit including DPS
- NAL unit Type for NAL unit including VPS
- NAL unit Type for NAL unit including SPS
- NAL unit Type for NAL unit including PPS
- NAL unit types have syntax information for the NAL unit type, and the syntax information may be stored in the NAL unit header and signaled.
- the syntax information may be nal_unit_type, and NAL unit types may be specified as nal_unit_type values.
- the slice header may include information/parameters commonly applicable to the slice.
- the APS APS syntax
- PPS PPS syntax
- the SPS SPS syntax
- the VPS VPS syntax
- the DPS DPS syntax
- the DPS may include information/parameters commonly applicable to the entire video.
- the DPS may include information/parameters related to concatenation of a coded video sequence (CVS).
- a high level syntax may include at least one of the APS syntax, PPS syntax, SPS syntax, VPS syntax, DPS syntax, and slice header syntax.
- the image/video information encoded by the encoding device to the decoding device and signaled in the form of a bitstream not only includes intra-picture partitioning information, intra/inter prediction information, residual information, in-loop filtering information, etc. It may include information included in the slice header, information included in the APS, information included in the PPS, information included in the SPS, and/or information included in the VPS.
- Intra prediction may represent prediction of generating prediction samples for a current block based on reference samples in a picture (hereinafter, referred to as a current picture) to which the current block belongs.
- surrounding reference samples to be used for intra prediction of the current block 1601 may be derived.
- the neighboring reference samples of the current block are a total of 2xnH samples including samples 1611 adjacent to the left boundary of the current block of size nWxnH and samples 1612 adjacent to the bottom-left side.
- the peripheral reference samples of the current block may include a plurality of columns of upper peripheral samples and a plurality of rows of left peripheral samples.
- the neighboring reference samples of the current block are a total of nH samples 1641 adjacent to the right boundary of the current block of size nWxnH, and a total of nW samples 1651 adjacent to the bottom boundary of the current block. And one sample 1642 neighboring the bottom-right side of the current block.
- the decoding apparatus may construct neighboring reference samples to be used for prediction by substituting samples that are not available with available samples.
- neighboring reference samples to be used for prediction may be configured through interpolation of available samples.
- a prediction sample can be derived based on an average or interpolation of neighboring reference samples of the current block, and (ii) neighboring reference samples of the current block Among them, the prediction sample may be derived based on a reference sample existing in a specific (prediction) direction with respect to the prediction sample.
- it may be called a non-directional mode or a non-angular mode
- it may be called a directional mode or an angular mode.
- a prediction sample may be generated.
- LIP linear interpolation intra prediction
- chroma prediction samples may be generated based on luma samples using a linear model. This case may be called LM mode.
- a temporary prediction sample of the current block is derived based on the filtered surrounding reference samples, and at least one derived according to the intra prediction mode among the existing surrounding reference samples, that is, unfiltered surrounding reference samples.
- a prediction sample of the current block may be derived by weighted summation of a reference sample and the temporary prediction sample.
- the above-described case may be referred to as PDPC (Position dependent intra prediction).
- a reference sample line with the highest prediction accuracy is selected among the neighboring multi-reference sample lines of the current block, and a prediction sample is derived from the reference sample located in the prediction direction, and at this time, the used reference sample line is decoded.
- Intra prediction encoding can be performed by instructing (signaling) the device.
- the above-described case may be referred to as multi-reference line (MRL) intra prediction or MRL-based intra prediction.
- MRL multi-reference line
- the current block is divided into vertical or horizontal subpartitions, and intra prediction is performed based on the same intra prediction mode, but neighboring 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, but by deriving and using neighboring reference samples in units of the subpartitions, intra prediction performance may be improved in some cases.
- This prediction method may be called intra sub-partitions (ISP) or ISP-based intra prediction.
- ISP intra sub-partitions
- These intra prediction methods may be referred to as intra prediction types in distinction from intra prediction modes (e.g. DC mode, planar mode, and directional mode).
- the intra prediction type may be referred to as various terms such as an intra prediction technique or an additional intra prediction mode.
- the intra prediction type may include at least one of the aforementioned LIP, PDPC, MRL, and ISP.
- a general intra prediction method excluding a specific intra prediction type such as LIP, PDPC, MRL, and ISP may be referred to as a normal intra prediction type.
- the normal intra prediction type may refer to a case in which the specific intra prediction type as described above is not applied, and prediction may be performed based on the aforementioned intra prediction mode. Meanwhile, post-processing filtering may be performed on the derived prediction samples as necessary.
- the intra prediction procedure may include an intra prediction mode/type determination step, a neighbor reference sample derivation step, and an intra prediction mode/type-based prediction sample derivation step. Also, if necessary, a post-filtering step may be performed on the derived prediction samples.
- ALWIP affiliate linear weighted intra prediction
- the ALWIP may be called linear weighted intra prediction (LWIP) or matrix weighted intra prediction or matrix based intra prediction (MIP).
- LWIP linear weighted intra prediction
- MIP matrix based intra prediction
- prediction samples for the current block may be derived by further performing a horizontal/vertical interpolation procedure.
- the intra prediction modes used for the MIP may be configured differently from the intra prediction modes used in the LIP, PDPC, MRL, and ISP intra prediction described above, or normal intra prediction.
- the intra prediction mode for the MIP may be referred to as a MIP intra prediction mode, a MIP prediction mode, or a MIP mode.
- a matrix and an offset used in the matrix vector multiplication may be set differently according to the intra prediction mode for the MIP.
- the matrix may be referred to as a (MIP) weight matrix
- the offset may be referred to as a (MIP) offset vector or a (MIP) bias vector.
- the block reconstruction procedure based on intra prediction and the intra prediction unit in the encoding apparatus may schematically include, for example, the following.
- S1710 may be performed by the intra prediction unit 185 of the encoding apparatus
- S1720 is the subtraction unit 115, the transform unit 120, the quantization unit 130, the inverse quantization unit 140, and the inverse transform unit ( 150) may be performed by the residual processing unit including at least one.
- S1720 may be performed by the subtraction unit 115 of the encoding apparatus.
- the prediction information may be derived by the intra prediction unit 185 and encoded by the entropy encoding unit 190.
- the residual information may be derived by the residual processing unit and may be encoded by the entropy encoding unit 190.
- the residual information is information on the residual samples.
- the residual information may include information on quantized transform coefficients for the residual samples.
- the residual samples may be derived as transform coefficients through the transform unit 120 of the encoding apparatus, and the transform coefficients may be derived as quantized transform coefficients through the quantization unit 130.
- Information on the quantized transform coefficients may be encoded by the entropy encoding unit 190 through a residual coding procedure.
- the encoding apparatus may perform intra prediction on the current block (S1710).
- the encoding apparatus may derive an intra prediction mode/type for the current block, derive neighboring reference samples of the current block, and generate prediction samples in the current block based on the intra prediction mode/type and the neighboring reference samples. do.
- the procedure of determining the intra prediction mode/type, deriving neighboring reference samples, and generating prediction samples may be performed simultaneously, or one procedure may be performed before the other procedure.
- the intra prediction unit 185 of the encoding apparatus may include an intra prediction mode/type determination unit, a reference sample derivation unit, and a prediction sample derivation unit.
- An intra prediction mode/type for the current block may be determined, a reference sample derivation unit may derive neighboring reference samples of the current block, and a prediction sample derivation unit may derive prediction samples of the current block. Meanwhile, when a prediction sample filtering procedure described later is performed, the intra prediction unit 185 may further include a prediction sample filter.
- the encoding apparatus may determine a mode/type applied to the current block from among a plurality of intra prediction modes/types. The encoding apparatus may compare RD costs for the intra prediction modes/types and determine an optimal intra prediction mode/type for the current block.
- the encoding apparatus may perform a prediction sample filtering procedure.
- Predictive sample filtering may be referred to as post filtering. Some or all of the prediction samples may be filtered by the prediction sample filtering procedure. In some cases, the prediction sample filtering procedure may be omitted.
- the encoding apparatus may generate residual samples for the current block based on the (filtered) prediction samples (S1720).
- the encoding apparatus may compare the prediction samples from the original samples of the current block based on a phase, and derive the residual samples.
- the encoding apparatus may encode image information including information about the intra prediction (prediction information) and residual information about the residual samples (S1730).
- the prediction information may include the intra prediction mode information and the intra prediction type information.
- the encoding apparatus may output the encoded image information in the form of a bitstream.
- the output bitstream may be delivered to a decoding device through a storage medium or a network.
- the residual information may include a residual coding syntax to be described later.
- the encoding apparatus may transform/quantize the residual samples to derive quantized transform coefficients.
- the residual information may include information on the quantized transform coefficients.
- the encoding apparatus may generate a reconstructed picture (including reconstructed samples and a reconstructed block). To this end, the encoding apparatus may perform inverse quantization/inverse transformation on the quantized transform coefficients again to derive (modified) residual samples. The reason for performing inverse quantization/inverse transformation after transforming/quantizing the residual samples in this way is to derive residual samples identical to the residual samples derived from the decoding apparatus as described above.
- the encoding apparatus may generate a reconstructed block including reconstructed samples for the current block based on the prediction samples and the (modified) residual samples. A reconstructed picture for the current picture may be generated based on the reconstructed block. As described above, an in-loop filtering procedure or the like may be further applied to the reconstructed picture.
- a video/image decoding procedure based on intra prediction and an intra prediction unit in the decoding apparatus may schematically include, for example, the following.
- the decoding apparatus may perform an operation corresponding to an operation performed by the encoding apparatus.
- S1810 to S1830 may be performed by the intra prediction unit 265 of the decoding apparatus, and the prediction information of S1810 and the residual information of S1840 may be obtained from the bitstream by the entropy decoding unit 210 of the decoding apparatus.
- the residual processing unit including at least one of the inverse quantization unit 220 and the inverse transform unit 230 of the decoding apparatus may derive residual samples for the current block based on the residual information.
- the inverse quantization unit 220 of the residual processing unit derives transform coefficients by performing inverse quantization based on the quantized transform coefficients derived based on the residual information
- the inverse transform unit of the residual processing unit ( 230) may derive residual samples for the current block by performing inverse transform on the transform coefficients.
- S1850 may be performed by the addition unit 235 or the restoration unit of the decoding apparatus.
- the decoding apparatus may derive an intra prediction mode/type for the current block based on the received prediction information (intra prediction mode/type information) (S1810).
- the decoding apparatus may derive neighboring reference samples of the current block (S1820).
- the decoding apparatus may generate prediction samples in the current block based on the intra prediction mode/type and the neighboring reference samples (S1830).
- the decoding apparatus may perform a prediction sample filtering procedure. Predictive sample filtering may be referred to as post filtering. Some or all of the prediction samples may be filtered by the prediction sample filtering procedure. In some cases, the prediction sample filtering procedure may be omitted.
- the decoding apparatus may generate residual samples for the current block based on the received residual information.
- the decoding apparatus may generate reconstructed samples for the current block based on the prediction samples and the residual samples, and derive a reconstructed block including the reconstructed samples (S1840).
- a reconstructed picture for the current picture may be generated based on the reconstructed block.
- an in-loop filtering procedure or the like may be further applied to the reconstructed picture.
- the intra prediction unit 265 of the decoding apparatus may include an intra prediction mode/type determination unit, a reference sample derivation unit, and a prediction sample derivation unit, and the intra prediction mode/type determination unit is entropy decoding. Based on the intra prediction mode/type information obtained by the unit 210, an intra prediction mode/type for the current block is determined, a reference sample derivation unit derives neighboring reference samples of the current block, and a prediction sample derivation unit Predictive samples of the current block can be derived. Meanwhile, when the above-described prediction sample filtering procedure is performed, the intra prediction unit 265 may further include a prediction sample filter unit.
- the intra prediction mode information may include flag information (ex. intra_luma_mpm_flag) indicating whether, for example, most probable mode (MPM) is applied to the current block or a remaining mode is applied, and the When MPM is applied to the current block, the prediction mode information may further include index information (ex. intra_luma_mpm_idx) indicating one of the intra prediction mode candidates (MPM candidates).
- the intra prediction mode candidates (MPM candidates) may be composed of an MPM candidate list or an MPM list.
- the intra prediction mode information includes remaining mode information (ex. intra_luma_mpm_remainder) indicating one of the remaining intra prediction modes excluding the intra prediction mode candidates (MPM candidates). It may contain more.
- the decoding apparatus may determine an intra prediction mode of the current block based on the intra prediction mode information.
- a separate MPM list may be configured for the above-described MIP.
- the intra prediction type information may be implemented in various forms.
- the intra prediction type information may include intra prediction type index information indicating one of the intra prediction types.
- the intra prediction type information includes reference sample line information (ex. intra_luma_ref_idx) indicating whether the MRL is applied to the current block and, if applied, a reference sample line (eg, intra_luma_ref_idx), and the ISP is the current block.
- ISP flag information indicating whether it is applied to (ex. intra_subpartitions_mode_flag), ISP type information indicating the split type of subpartitions when the ISP is applied (ex.
- intra_subpartitions_split_flag flag information indicating whether PDCP is applied, or LIP application It may include at least one of flag information indicating whether or not.
- the intra prediction type information may include a MIP flag indicating whether MIP is applied to the current block.
- the intra prediction mode information and/or the intra prediction type information may be encoded/decoded through the coding method described in this document.
- the intra prediction mode information and/or the intra prediction type information may be encoded/decoded through entropy coding (ex. CABAC, CAVLC) coding based on a truncated (rice) binary code.
- the residual processing procedure performed by the encoding apparatus may include a procedure of generating and/or encoding (encoding) residual information from residual samples for the derived current block.
- the residual processing procedure may further include a procedure of deriving the residual samples based on prediction samples.
- the residual processing procedure performed by the decoding apparatus may include a procedure of deriving residual samples from residual information of a bitstream received from the encoding apparatus.
- the residual processing procedure may include a (inverse) transformation and/or (inverse) quantization procedure.
- the residual processing procedure may include an encoding/decoding (encoding/decoding) procedure of residual information.
- the residual information may include residual data and/or a transformation/quantization related parameter.
- the encoded information may be output in the form of a bitstream.
- (quantized) transform coefficients or (quantized) residual coefficients in a block are derived from residual information (or residual information for transform skip) included in the bitstream, and inverse quantized (if necessary).
- residual information or residual information for transform skip
- inverse quantized if necessary.
- FIG. 19 and 20 are diagrams illustrating a residual processing method according to an exemplary embodiment. Each step shown in FIG. 19 may be performed by an encoding device.
- S1910 may be performed by the inter prediction unit 180 or the intra prediction unit 185 of the encoding apparatus 100
- S1920, S1930, S1940, and S1950 are each subtractor ( 115), the transform unit 120, the quantization unit 130, and the entropy encoding unit 190.
- the encoding apparatus may derive prediction samples through prediction of the current block (S1910).
- the encoding apparatus may determine whether to perform inter prediction or intra prediction on the current block, and may determine a specific inter prediction mode or a specific intra prediction mode based on RD cost. According to the determined mode, the encoding apparatus may derive prediction samples for the current block.
- the encoding apparatus may generate residual samples for the current block based on the prediction sample (S1920). For example, the encoding apparatus may derive residual samples by comparing original samples for the current block with the prediction samples.
- Quantized transform coefficients may be derived by quantizing the derived transform coefficients (S1940).
- quantization may be performed based on a quantization parameter.
- the conversion procedure and/or the quantization procedure may be omitted.
- (quantized) (residual) coefficients for residual samples may be coded according to a residual coding technique to be described later.
- the (quantized) (residual) coefficient may also be called a (quantized) transform coefficient for unification of terms.
- the encoding apparatus may encode image information including prediction information and residual information, and output the encoded image information in the form of a bitstream (S1950).
- the prediction information is information related to the prediction procedure and may include prediction mode information and information about motion information (eg, when inter prediction is applied).
- the residual information includes information on the (quantized) transform coefficients, for example, information disclosed in a residual coding syntax (residual_coding()) to be described later or a transform skip residual coding syntax (residual_ts_coding()). It may also include disclosed information.
- the output bitstream may be delivered to an encoding device through a storage medium or a network.
- each step shown in FIG. 20 may be performed by the decoding apparatus.
- S2010 may be performed by the inter prediction unit 260 or the intra prediction unit 265 of the encoding apparatus 200.
- a procedure for deriving values of related syntax elements by decoding prediction information included in the bitstream in S2010 may be performed by the entropy decoding unit 210 of the encoding apparatus 200.
- S2020, S2030, S2040, and S2050 may be performed by the entropy decoding unit 210, the inverse quantization unit 220, the inverse transform unit 230, and the adder 235 of the encoding apparatus 200, respectively.
- the encoding device may perform an operation corresponding to an operation performed by the encoding device.
- the encoding apparatus may perform inter prediction or intra prediction on the current block based on the received prediction information and derive prediction samples (S2010).
- the encoding apparatus may derive quantized transform coefficients for the current block based on the received residual information (S2020).
- the encoding apparatus may derive the quantized transform coefficients from the residual information through entropy decoding.
- the inverse quantization may be performed based on a quantization parameter.
- the encoding apparatus may inverse quantize the quantized transform coefficients to derive transform coefficients (S2030).
- the encoding apparatus may derive residual samples through an inverse transform procedure for the transform coefficients (S2040).
- the inverse transformation procedure and/or the inverse quantization procedure may be omitted.
- (quantized) (residual) coefficients may be derived from the residual information, and residual samples may be derived based on the (quantized) (residual) coefficients.
- the decoding apparatus may generate a reconstructed picture based on the prediction samples and the residual samples (S2050). For example, the encoding apparatus may generate reconstructed samples for the current block based on the prediction samples and the residual samples, and generate a reconstructed picture based on this. Thereafter, as described above, an in-loop filtering procedure may be further applied to the reconstructed picture.
- residual samples may be derived into quantized transform coefficients through a transform and quantization process.
- the quantized transform coefficients may also be called transform coefficients.
- the transform coefficients within the block may be signaled in the form of residual information.
- the residual information may include residual coding syntax. That is, the encoding apparatus may construct a residual coding syntax with residual information, encode it, and output it in a bitstream form, and the encoding apparatus decodes the residual coding syntax from the bitstream to obtain residual (quantized) transform coefficients.
- the residual coding syntax is a syntax element indicating where the position of the last effective transform coefficient in the corresponding block is, whether there is an effective transform coefficient in the subblock, and the size/code of the effective transform coefficient. ) Can be included.
- the transform coefficients of the VVC is last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix, last_sig_coeff_y_suffix, coded_sub_block_flag, sig_coeff_flag, abs_level_gtX_flag [n] [0], par_level_flag, abs_level_gtX_flag [n] [1], abs_remainder, dec_abs_level, coeff_sign_flag syntax element (syntax element) It can be coded using This may be referred to as residual (data) coding or (transform) coefficient coding.
- the residual coding process that undergoes the transformation and quantization process as described above may be referred to as a regular residual coding pass, which may be specified as the residual_coiding() syntax of FIGS. 21 to 27.
- the conversion/quantization process may be omitted.
- values of the residual samples may be coded and signaled according to a predetermined method.
- the residual coding process in which the transform and/or quantization process is omitted may be referred to as a transform skip residual coding pass, which may be specified as the residual_ts_coding() syntax of FIGS. 29 to 31.
- FIGS. 21 to 27 show syntax elements related to the residual data coding.
- syntax elements described in the syntax of FIGS. 21 to 27 will be briefly described.
- the name of the syntax element described below is an example, and the scope of the present disclosure is not limited by the name of the syntax element.
- the array AbsLevel[xC][yC] may represent an array consisting of absolute values of transform coefficient levels for the current transform block.
- the array AbsLevelPass1[xC][yC] may represent an array consisting of values representing a part of the absolute value of the transform coefficient level for the current transform block.
- the array indices xC and yC may represent transform coefficient positions (xC, yC) in the current transform block.
- AbsLevel[xC][yC] When the value of AbsLevel[xC][yC] is not provided through the syntax of FIGS. 21 to 27, the value of AbsLevel[xC][yC] may be derived as 0. In addition, even when the value of AbsLevelPass1[xC][yC] is not provided through the syntax of FIGS. 21 to 27, the value of AbsLevelPass1[xC][yC] may be derived as 0.
- variable CoeffMin representing the minimum conversion coefficient value
- variable CoeffMax representing the maximum conversion coefficient value
- the array QStateTransTable[][] can be defined as follows.
- the syntax elements last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix, and last_sig_coeff_y_suffix may represent the position of the last significant coefficient identified according to the scan order of samples in the transform block among coefficients in the transform block.
- the effective coefficient may be a coefficient having a non-zero value.
- last_sig_coeff_x_prefix may indicate a prefix of the column position of the last significant coefficient.
- last_sig_coeff_x_prefix may have a value from 0 to (log2ZoTbWidth ⁇ 1) -1.
- the value of log2ZoTbWidth may be determined according to the syntax of FIG. 21.
- last_sig_coeff_y_prefix may represent a prefix of the row position of the last significant coefficient.
- last_sig_coeff_y_prefix can have a value from 0 to (log2ZoTbHeight ⁇ 1) -1.
- log2ZoTbHeight may be determined according to the syntax of FIG. 21.
- last_sig_coeff_x_suffix may represent the suffix of the column position of the last significant coefficient.
- last_sig_coeff_x_suffix can have a value from 0 to (1 ⁇ ((last_sig_coeff_x_prefix >> 1)-1))-1.
- variable LastSignificantCoeffX indicating the column position of the last significant coefficient according to the scan order in the transform block can be derived as follows.
- LastSignificantCoeffX may be determined as shown in the following equation.
- LastSignificantCoeffX last_sig_coeff_x_prefix
- LastSignificantCoeffX may be determined as shown in the following equation.
- LastSignificantCoeffX (1 ⁇ ((last_sig_coeff_x_prefix >> 1)-1)) * (2 + (last_sig_coeff_x_prefix & 1)) + last_sig_coeff_x_suffix
- last_sig_coeff_y_suffix may represent the suffix of the row position of the last significant coefficient.
- last_sig_coeff_y_suffix can have a value from 0 to (1 ⁇ ((last_sig_coeff_y_prefix >> 1)-1))-1.
- variable LastSignificantCoeffY representing the behavior value of the last significant coefficient according to the scan order in the transform block can be derived as follows.
- LastSignificantCoeffY may be determined as shown in the following equation.
- LastSignificantCoeffY last_sig_coeff_y_prefix
- LastSignificantCoeffY may be determined as shown in the following equation.
- LastSignificantCoeffY (1 ⁇ ((last_sig_coeff_y_prefix >> 1)-1)) * (2 + (last_sig_coeff_y_prefix & 1)) + last_sig_coeff_y_suffix
- the scan order may be one of an upward-right diagonal scan order, a left-down diagonal scan order, a horizontal scan order, and a vertical scan order.
- the horizontal scan order may mean a scan order from left to right
- the vertical scan order may mean a scan order from top to bottom.
- the scan order may be determined based on whether intra/inter prediction is applied to the target block and/or a specific intra/inter prediction mode.
- the syntax element coded_sub_block_flag[xS, yS] may indicate the following information for a subblock existing at the (xS, yS) position in the current transform block.
- the sub-block may be a 4x4 array consisting of 16 transform coefficient levels.
- the first value (e.g. 0) of the coded_sub_block_flag may indicate that 16 transform coefficient levels of the sub-block at the (xS, yS) position are derived to be 0.
- the second value (e.g. 1) of coded_sub_block_flag may indicate information according to the following conditions. For example, if (xS, yS) is (0, 0) and (LastSignificantCoeffX, LastSignificantCoeffY) is not (0, 0 ), the second value (eg 1) of coded_sub_block_flag is the subblock at the (xS, yS) position. It may indicate that at least one syntax element among 16 sig_coeff_flag syntax elements is provided for. Otherwise, the second value (e.g. 1) of the coded_sub_block_flag may indicate that at least one of the 16 sig_coeff_flag for the subblock at the (xS, yS) position has a non-zero value.
- coded_sub_block_flag[xS, yS] when the value of coded_sub_block_flag[xS, yS] is not provided from the bitstream, the value thereof may be derived as a second value (e.g. 1).
- the syntax element sig_coeff_flag[xC, yC] may indicate whether the transform coefficient level corresponding to the position (xC, yC) is non-zero with respect to the transform coefficient position (xC, yC) in the current transform block.
- the first value (e.g. 0) of sig_coeff_flag[xC][yC] may indicate that the transform coefficient level at the position (xC, yC) is 0.
- the corresponding transform coefficient level may be set to 0.
- the second value (e.g. 1) of sig_coeff_flag[xC][yC] may indicate that the transform coefficient level at the position (xC, yC) is a non-zero value.
- sig_coeff_flag[xC, yC] is not provided in the bitstream, it can be derived as follows.
- the position (xC, yC) is the last significant count position (eg LastSignificantCoeffX, LastSignificantCoeffY) in the scan order, or when all of the following conditions 1 to 3 are true, the value of sig_coeff_flag[xC, yX] is the second value (eg 1 ) Can be derived. Otherwise, the value of sig_coeff_flag[xC, yX] may be derived as a first value (e.g. 0).
- abs_level_gtx_flag[ n ][ j] may indicate whether the absolute value of the transform coefficient level at the scan position n is greater than (j ⁇ 1) + 1.
- the first value (e.g. 0) of abs_level_gtx_flag[ n ][ j] may indicate that the absolute value of the transform coefficient level at scan position n is not greater than (j ⁇ 1) + 1.
- the second value (e.g. 1) of abs_level_gtx_flag[ n ][ j] may indicate that the absolute value of the transform coefficient level at the scan position n is greater than (j ⁇ 1) + 1.
- abs_level_gtx_flag[ n ][ j] is not provided in the bitstream, it may be derived as a first value (e.g. 0).
- par_level_flag[n] may indicate the parity of the transform coefficient level at the scan position n.
- par_level_flag[n] When par_level_flag[n] is not provided in the bitstream, its value may be derived as 0.
- abs_remainder[n] may represent a residual absolute value of a transform coefficient level encoded with a Golomb-Rice code at scan position n. If abs_remainder[n] is not provided in the bitstream, its value may be derived as 0.
- the value of abs_remainder[n] may be limited to a value such that the corresponding TransCoeffLevel[x0][y0][cIdx][xC][yC] has a value between CoeffMin and CoeffMax. have.
- the syntax element dec_abs_level[n] may represent an intermediate value encoded with a Golomb-Rice code at scan position n.
- the absolute value AbsLevel[xC][yC] of the transform coefficient level at the (xC, yC) position can be derived as follows. For example, when the value of dec_abs_level[n] is equal to ZeroPos[n], the value of AbsLevel[xC][yC] may be set to 0. Meanwhile, when the value of dec_abs_level[n] is less than ZeroPos[n], the value of AbsLevel[xC][yC] may be set to dec_abs_level[n]+1.
- the value of dec_abs_level[n] is greater than ZeroPos[n]
- the value of AbsLevel[xC][yC] may be set to dec_abs_level[n].
- ZeroPos[n] may be determined during the encoding process, and may be signaled through a bitstream.
- AbsLevelPass1[xC][yC] can be derived as shown in the following equation.
- AbsLevelPass1[ xC ][ yC] Min( 4 + (AbsLevel[ xC ][ yC] & 1 ), AbsLevel[ xC ][ yC])
- dec_abs_level[n] may be limited to a value such that the corresponding TransCoeffLevel[x0][y0][cIdx][xC][yC] has a value between CoeffMin and CoeffMax. .
- the syntax element coeff_sign_flag[n] may represent the sign of the transform coefficient level at the scan position n as follows. For example, if the value of coeff_sign_flag[n] is a first value (e.g. 0), the corresponding transform coefficient level may have a positive sign.
- the sign of the corresponding transform coefficient level may have a negative sign.
- the value of coeff_sign_flag[n] may be derived as a first value (e.g. 0).
- the value of CoeffSignLevel[xC][yC] indicating the sign of the transform coefficient level at the position (xC, yC) can be derived as follows. For example, if the value of CoeffSignLevel[xC][yC] is 0, the corresponding transform coefficient level may be set to 0.
- the corresponding transform coefficient level may be set to a positive value.
- the corresponding transform coefficient level may be set to a negative value.
- the syntax elements last_sig_coeff_x_prefix, last_sig_coeff_y_prefix, last_sig_coeff_x_suffix, and last_sig_coeff_y_suffix are syntax elements that encode (x, y) position information of the last non-zero coefficient in the associated block.
- the associated block may be a coding block (CB) or a transform block (TB).
- CB and TB may be used interchangeably.
- residual samples are derived for CB, and (quantized) transform coefficients can be derived through transform and quantization of the residual samples.
- Information or syntax elements
- Quantized transform coefficients can be simply called transform coefficients.
- the size of the CB may be the same as the size of the TB.
- the target block to be transformed (and quantized) and residual coded may be referred to as CB and may be referred to as TB.
- the target block to be transformed (and quantized) and residual coded may be referred to as TB.
- syntax elements related to residual coding are described as being signaled in units of a transform block (TB), but this is an example, as described above, that the TB can be mixed with a coding block (CB).
- last_sig_coeff_x_prefix indicates the prefix of the column position of the last significant coefficient in the scanning order in the transform block
- last_sig_coeff_y_prefix is the scan in the transform block
- the prefix of the row position of the last significant coefficient in the sequence can be indicated.
- last_sig_coeff_x_suffix indicates the suffix of the column position of the last significant coefficient in the scan order in the transform block
- last_sig_coeff_y_suffix indicates the suffix of the row position of the last significant coefficient in the scan order in the transform block.
- the effective coefficient may mean a non-zero coefficient.
- the scan order may be an upward-right diagonal scan order.
- the scan order may be one of a left-to-down diagonal scan order, a horizontal scan order, and a vertical scan order.
- the horizontal scan order may mean a scan order from left to right
- the vertical scan order may mean a scan order from top to bottom.
- the scan order may be determined based on whether intra/inter prediction is applied to a target block (CB or CB including TB) and/or a specific intra/inter prediction mode. Using this, the encoding apparatus may encode the position of the last significant coefficient.
- the encoding apparatus may indicate whether a non-zero coefficient exists in the current sub-block by using a 1-bit syntax element coded_sub_block_flag for each 4x4 sub-block.
- the sub-block may also be referred to as a coefficient group (CG).
- coded_sub_block_flag If the value of coded_sub_block_flag is 0, since there is no more information to be transmitted, the encoding process for the subblock may be terminated. Conversely, if the value of coded_sub_block_flag is 1, the sig_coeff_flag encoding process may be performed. When the scan order is followed, coding for coded_sub_block_flag may not be performed for a subblock including a coefficient other than 0 last. In addition, since a subblock including DC information of the transform block has a high probability of including a coefficient other than 0, coded_sub_block_flag is not encoded, and its value may be set to 1.
- sig_coeff_flag having a binary value may be encoded according to the reverse scan order.
- a 1-bit syntax element sig_coeff_flag[n] may be encoded for each coefficient of the corresponding scan position n according to the scan order. If the value of the coefficient at the current scan position is not 0, the value of sig_coeff_flag[n] may be 1.
- the encoding process may be omitted.
- Level information encoding may be performed only when sig_coeff_flag[n] is 1.
- the level information encoding/decoding process may be performed using at least one of the above-described syntax elements.
- the syntax element sig_coeff_flag[xC][yC] may indicate whether the level (value) of the corresponding transform coefficient at each transform coefficient position (xC, yC) in the current TB is 0.
- the level value remaining after sig_coeff_flag[n] encoding may be derived according to the following equation.
- the syntax element remAbsLevel[n] may indicate a level value to be encoded at the scan position n.
- coeff[n] may mean an actual transform coefficient value.
- abs_level_gtX_flag[n][0] may indicate whether remAbsLevel[n] at the scan position n is greater than 1.
- the absolute value of the corresponding position coefficient may be 1.
- remAbsLevel[n] can be derived according to the following equation.
- par_level_flag[n] may represent the parity of the transform coefficient level (value) at the scan position n.
- level value remAbsLevel[n] to be encoded may be updated according to the following equation.
- par_level_flag[n] remAbsLevel[n] & 1
- abs_level_gtX_flag[n][1] may indicate whether remAbsLevel[n] at the scan position n is greater than 3.
- abs_remainder[n] can be encoded only when abs_level_gtX_flag[n][1] is 1.
- the relationship between coeff[n] and each syntax element may be as follows. At this time,
- coeff_sign_flag[n] may indicate a transform coefficient sign at a corresponding scan position n.
- abs_level_gtx_flag[n][i] may be a syntax element indicating whether the absolute value of the transform coefficient is greater than any one of 1 or 3.
- coeff_sign_flag[n] may represent the sign of the transform coefficient level at the corresponding scan position n.
- CABAC provides high performance, but has a disadvantage of poor throughput performance. This may be due to the above-described regular encoding engine of CABAC. Since the regular encoding engine uses the updated probability state and range through encoding of the previous bin, it shows high data dependence, and it takes a lot of time to read the probability interval and determine the current state. In this case, if the number of context encoding bins is limited, the throughput problem of CABAC can be solved.
- the sum of bins used to represent sig_coeff_flag[n], abs_level_gtX_flag[n][0], par_level_flag[n], and abs_level_gtx_flag[n][1] may be limited according to the size of the transform block. Specifically, the sum of bins may be limited to a value of ((1 ⁇ (log2TbWidth+log2TbHeight))*7)>>2. As such, the sum of bins may be limited to a number of 1.75 times the size of the transform block including the current CG, which may mean that 1.75 context encoding bins may be used per one pixel position on average.
- bypass encoding may be performed without CABAC being applied to the remaining coefficients. That is, when the number of encoded text encoding bins becomes TU width * TU height * 1.75 in the TU, sig_coeff_flag[n], abs_level_gtX_flag[n][0], par_level_flag[n], abs_level_gtX_flag[n] are no longer encoded as context encoding bins. ][1] may not be additionally encoded. In this case,
- FIGS. 28 to 31 shows syntax in a transform unit indicating signaling of a transform skip flag (transform_skip_flag), and FIGS. 29 to 31 show syntax in a transform skip residual coding pass.
- the transform unit 120 of the image encoding apparatus may generate transform coefficients by performing transform on the residual signal.
- the transform coefficients may be signaled to the image decoding apparatus through quantization and entropy encoding, and the inverse transform unit 230 of the image decoding apparatus may restore the transform coefficients by performing inverse transform on the transform coefficient.
- the image encoding apparatus may perform entropy encoding without performing transformation on a residual signal, and this operation of the image encoding apparatus may be defined as a transformation skip process or application of a transformation skip mode.
- the inverse transform unit 230 of the image decoding apparatus may not perform inverse transform with respect to the residual signal from which the transform is omitted.
- the image encoding apparatus may transmit information indicating whether the transform skip mode is applied to the current block.
- the apparatus for encoding an image may signal whether the transform skip mode is applied to the current block through the syntax element transform_skip_flag.
- transform_skip_flag[x0][y0] may indicate whether or not transform is applied to the luma transform block.
- x0 and y0 may represent positions (x0, y0) of the upper left luma sample of the current transform block with respect to the upper left sample position of the current picture.
- the first value (e.g. 0) of transform_skip_flag[x0][y0] may indicate that whether or not the transform is applied to the luma transform block is determined based on values of other syntax elements.
- the second value (e.g. 1) of transform_skip_flag[x0][y0] may indicate that no transform is applied to the luma transform block.
- the value of transform_skip_flag[x0][y0] is not provided from the bitstream, the value thereof can be derived as follows. For example, when the value of BdpcmFlag[x0][y0] is the first value (e.g. 0), the value of transform_skip_flag[x0][y0] may be determined as the first value (e.g. 0). Otherwise, when the value of BdpcmFlag[x0][y0] is the second value (e.g. 1), the value of transform_skip_flag[x0][y0] may be determined as the second value (e.g. 1). BdpcmFlag will be described later.
- transform_skip_flag may be signaled based on at least one of the height, width, and maximum transform size of the current block. For example, whether to encode/decode transform_skip_flag of the current block may be determined according to the condition of the following equation.
- transform_skip_enabled_flag may be a syntax element indicating whether the transform skip mode is applicable, and may be signaled at at least one of a sequence level, a picture level, a tile level, a tile group level, and a slice level.
- transform_skip_enabled_flag when transform_skip_enabled_flag is signaled at the sequence level, transform_skip_enabled_flag may be named sps_transform_skip_enabled_flag as shown in FIG. 28.
- FIGS. 29 to 31 illustrate an embodiment of a residual coding pass (residual_ts_coding()) for signaling a transform coefficient when a transform skip mode is applied to a current block.
- encoding/decoding of the above-described residual signal may be performed according to the following characteristics compared to the case where the transform is applied.
- the transform skip mode since the residual signal reflects the spatial residual after prediction and energy compression by transform is not performed, invalid levels or consecutive zero values at the lower right corner of the transform block The probability of this appearing is not high. Accordingly, signaling for the last valid scan position may not be required. Accordingly, when transform skip is applied, signaling for the last significant scanning position may be omitted. Instead, a subblock located at the bottom right of the transform block may be selected as the first subblock on which encoding or decoding is performed.
- coded_sub_block_flag As the last valid scan position is not signaled, when transformation is skipped, signaling whether a subblock is encoded using coded_sub_block_flag may be modified. For example, the last valid scan position can be removed.
- coded_block_flag may be encoded for all sub-blocks. Accordingly, if the values of all coded_sub_block_flag are not 0, coded_sub_block_flag of the DC subblock may also be signaled.
- context modeling for coded_sub_block_flag may also be modified.
- the context model index may be calculated as the sum or OR of coded_sub_block_flag of the right and lower neighboring blocks of the current sub-block.
- the local template in sig_coeff_flag may be modified to include only the right neighboring block NB 0 and the lower neighboring block NB 1 of the current scan position.
- the context model offset may be determined by the number of significant neighboring positions, and may be calculated as sig_coeff_flag[NB 0 ] + sig_coeff_flag[NB 1 ].
- abs_remainder[] encoding since the empirical distribution of transform-skipped residual absolute values generally corresponds to Laplacian or geometric distribution, it is shown to have greater instability than the absolute value of the transformed coefficient,
- abs_remainder syntax binarization and context modeling can be modified as follows.
- a high cutoff value may be used for binarization. For example, a transition point in encoding using sig_coeff_flag, abs_level_gtX_flag, and par_level_flag for Rice code of Abs_remainder, and dedicated context models for each bin position allow higher compression efficiency to be calculated. By increasing the cutoff, you can use a higher “greater than X” flag. For example, abs_level_gtX_flag[][2], abs_level_gtX_flag[][3],... , abs_level_gtX_flag[][n] may be used as a “greater than X” flag, where n may be 9 or an integer greater than 9.
- n may be 5.
- the value of abs_level_gtX_flag[][n] may be determined as (n ⁇ 1) + 1.
- abs_level_gtX_flag[][2] may be determined as 5
- abs_level_gtX_flag[][3] may be determined as 7
- abs_level_gtX_flag[][4] may be determined as 9
- abs_level_gtX_flag[][n] may be determined as 2n+1. have.
- the template for deriving the Rice parameter may be modified. For example, like the sig_coeff_flag context modeling described above, only the left and lower neighbors of the current scan position can be referenced.
- the sign can be encoded using a context model.
- a single dedicated context model can be used to encode the code, and the code can be parsed after sig_coeff_flag to collect the context encoding bins together.
- the transformation is skipped.
- the context encoding bins in the case may be limited to two per pixel at the TU level.
- a context coded bins (CCB) counter, MaxCcbs may be decreased. When the number of CCBs reaches the maximum bin, or when the CCB counter reaches 0 (e.g. TU width * TU height * 2), all syntax elements can be encoded like EP.
- the scan order of the subblocks and the coefficients of the subblocks may be directed from the upper left coefficient to the lower right position according to the diagonal scan order.
- absCoeffLevel which is an absolute coefficient level (value)
- a modified level value
- quantized residual samples located at the left and top of the current residual sample are It can be encoded in the following way based on the value. For example, if X0 means the absolute coefficient level (value) located to the left of the current coefficient and X1 means the absolute coefficient level (value) located at the top, the coefficient with the absolute coefficient level (value) absCoeff is expressed. To do this, the mapped absCoeffMod may be encoded in the following manner.
- absCoeffMod (absCoeff ⁇ pred)? absCoeff + 1: absCoeff;
- the context derivation for abs_level_gt1_flag may be performed by using the information of the upper neighbor coefficient and the left neighbor coefficient described above.
- a context offset eg ctxOffset
- a context offset 1 may be used when only one of X0 and X1 is a non-zero value.
- context offset 2 may be used.
- 3 may be used as the context offset.
- BDPCM Block Difference Pulse Code Modulation
- the image encoding apparatus and the image decoding apparatus may perform differential encoding of a residual signal.
- the image encoding apparatus may encode the residual signal by subtracting the prediction signal from the residual signal of the current block, and the image decoding apparatus adds the prediction signal to the residual signal of the current block to obtain the residual signal. It can be decrypted.
- An image encoding apparatus and an image decoding apparatus according to an embodiment may perform differential encoding of a residual signal by applying a BDPCM to be described later.
- the quantized residual domain may include a quantized residual signal (or a quantized residual coefficient), and when BDPCM is applied, transformation of the quantized residual signal may be skipped. For example, when BDPCM is applied, transformation may be skipped and quantization may be applied to the residual signal.
- the quantized residual domain may include quantized transform coefficients.
- the apparatus for encoding an image may derive a residual block of the current block predicted in the intra prediction mode, and quantize the residual block to derive the residual block.
- the image encoding apparatus may derive the modified residual block by performing differential encoding on the residual block.
- the image encoding apparatus may generate a bitstream by encoding differential encoding mode information indicating a differential encoding mode of a residual signal and the modified residual block.
- a predicted block (prediction block) including predicted samples of the current block may be generated by intra prediction.
- an intra prediction mode for performing intra prediction may be signaled through a bitstream, or may be derived based on a prediction direction of BDPCM, which will be described later.
- the intra prediction mode may be determined as one of a vertical prediction direction mode or a horizontal prediction direction mode. For example, when the prediction direction of the BDPCM is the horizontal direction, the intra prediction mode is determined as the horizontal prediction direction mode, and the prediction block of the current block may be generated by intra prediction in the horizontal direction.
- the intra prediction mode is determined as the vertical prediction direction mode, and the prediction block of the current block may be generated by intra prediction in the vertical direction.
- intra prediction in the horizontal direction a value of a pixel adjacent to the left of the current block may be determined as a predicted sample value of samples included in a corresponding row of the current block.
- intra prediction in the vertical direction a value of a pixel adjacent to the top of the current block may be determined as a predicted sample value of samples included in a corresponding column of the current block.
- a method of generating a prediction block of the current block may be performed in the same manner in an image encoding apparatus and an image decoding apparatus.
- the apparatus for encoding an image may generate a residual block including residual samples of the current block by subtracting the prediction block from the current block.
- the image encoding apparatus may encode a difference (or delta) between the quantized residual sample and a predictor of the quantized residual sample.
- the image decoding apparatus may generate a quantized residual block of the current block by obtaining a quantized residual sample of the current block based on a predictor and a difference value reconstructed from the bitstream. Thereafter, the image decoding apparatus may reconstruct the current block by inverse quantizing the quantized residual block and adding it to the prediction block.
- the residual block of FIG. 32 may be generated by the image encoding apparatus subtracting the prediction block from the current block.
- the quantized residual block of FIG. 32 may be generated by an image encoding apparatus quantizing the residual block.
- r i and j denote values of residual samples of (i, j) coordinates in the current block.
- the size of the current block is MxN
- the value i may be 0 or more and M-1 or less.
- the j value may be 0 or more and N-1 or less.
- the residual may represent the difference between the original block and the predicted block.
- r i, j can be derived by subtracting the value of the predicted sample from the value of the original sample of the (i, j) coordinate in the current block.
- r i, j is a horizontal intra prediction that copies the value of a left neighboring pixel along a line crossing the prediction block, using an unfiltered sample from the top or left boundary sample, or a prediction block It may be a prediction residual after performing vertical intra prediction that is copied to individual lines of.
- Q(r i, j ) represents a value of a quantized residual sample of (i, j) coordinates in the current block.
- Q(r i, j ) may represent quantized values of r i and j.
- the prediction of BDPCM is performed on the quantized residual samples of FIG. 32, and a modified quantized residual block of MxN size including modified quantized residual samples r' A residual block) R'may be generated.
- the values (r' i, j ) of the modified quantized residual sample of the coordinates (i, j) in the current block may be calculated as shown in the following equation.
- Equation 15 when the prediction direction of BDPCM one horizontal direction, r '0, j the value of the coordinates (0, j) is the value Q (r 0, j) of the quantized residual samples it is directly assigned.
- Other values of r'i, j of (i, j) coordinates are quantized residual values of Q(r i, j ) and (i-1, j) coordinates of quantized residual samples of (i, j) coordinates. It is derived as the difference value of the value Q(r i-1, j) of the dual sample.
- the quantized residual sample value Q(r i, j ) of the (i, j) coordinate instead of encoding the quantized residual sample value Q(r i, j ) of the (i, j) coordinate, the quantized residual sample value Q(r i-1) of the (i-1, j) coordinate.
- the difference value calculated using, j ) as a predicted value is derived as the modified quantized residual sample values (r' i, j ), and then the values of r'i and j are encoded.
- the values (r' i, j ) of the modified quantized residual sample of the coordinates (i, j) in the current block can be calculated as shown in the following equation.
- BDPCM prediction a process of modifying a current quantized residual sample value by using an adjacent quantized residual sample value as a prediction value.
- the image encoding apparatus may encode the modified quantized residual block including the modified quantized residual samples, and transmit the coded to the image decoding apparatus.
- transformation is not performed on the modified quantized residual block.
- 33 shows a modified quantized residual block generated by performing BDPCM of the present disclosure.
- horizontal BDPCM represents a modified quantized residual block generated according to Equation 15 when the prediction direction of the BDPCM is in the horizontal direction.
- vertical BDPCM represents a modified quantized residual block generated according to Equation 16 when the prediction direction of the BDPCM is a vertical direction.
- 34 is a flowchart illustrating a procedure for encoding a current block by applying BDPCM in an image encoding apparatus.
- a current block which is an encoding target block
- prediction may be performed on the current block to generate a prediction block (S3420).
- the prediction block of step S3420 may be an intra prediction block, and the intra prediction mode may be determined as described above.
- a residual block of the current block may be generated based on the prediction block generated in step S3420 (S3430).
- the apparatus for encoding an image may generate a residual block (the value of the residual sample) by subtracting the prediction block (the value of the predicted sample) from the current block (the value of the original sample).
- the residual block of FIG. 32 may be generated.
- Quantization is performed on the residual block generated in step S3430 (S3440), a quantized residual block is generated, and BDPCM prediction may be performed on the quantized residual block (S3450).
- the quantized residual block generated as a result of performing step S3440 may be a quantized residual block of FIG. 32, and a modified quantized residual block of FIG. 33 may be generated according to a BDPCM prediction result of step S3450 and a prediction direction. have. Since the BDPCM prediction in step S3450 has been described with reference to FIGS. 32 to 33, detailed descriptions are omitted.
- the apparatus for encoding an image may generate a bitstream by encoding the modified quantized residual block (S3460). In this case, the transform for the modified quantized residual block may be skipped.
- the BDPCM operation in the image encoding apparatus described with reference to FIGS. 32 to 34 may be performed in reverse by the image decoding apparatus.
- 35 is a flowchart illustrating a procedure for restoring a current block by applying BDPCM in an image decoding apparatus.
- the image decoding apparatus may obtain information (image information) necessary for reconstructing the current block from the bitstream (S3510).
- Information necessary for reconstructing the current block may include information about prediction of the current block (prediction information), information about a residual of the current block (residual information), and the like.
- the image decoding apparatus may perform prediction on the current block based on information on the current block and generate a prediction block (S3520).
- the prediction for the current block may be intra prediction, and a detailed description is the same as described with reference to FIG. 34.
- the step of generating a prediction block for the current block (S3520) is shown to be performed prior to steps S3530 to S3550 of generating a residual block of the current block.
- the present invention is not limited thereto, and a prediction block of the current block may be generated after the residual block of the current block is generated.
- the residual block of the current block and the prediction block of the current block may be generated at the same time.
- the image decoding apparatus may generate a residual block of the current block by parsing the residual information of the current block from the bitstream (S3530).
- the residual block generated in step S3530 may be a modified quantized residual block shown in FIG. 33.
- the image decoding apparatus may generate the quantized residual block of FIG. 32 by performing BDPCM prediction on the modified quantized residual block of FIG. 33 (S3540 ). Since the BDPCM prediction in step S3540 is a procedure of generating the quantized residual block in FIG. 32 from the modified quantized residual block in FIG. 33, it may correspond to the reverse process of step S3450 performed in the image encoding apparatus. For example, if the difference encoding mode information (eg bdpcm_flag) obtained from the bitstream indicates a differential encoding mode in which differential encoding of residual coefficients is performed as BDPCM is applied, differential encoding is performed on the residual block. To derive a modified residual block.
- the difference encoding mode information eg bdpcm_flag
- the image decoding apparatus may modify at least one residual coefficient to be modified among residual coefficients in the residual block by using the residual coefficient to be modified and the predicted residual coefficient.
- the prediction residual coefficient may be determined based on a prediction direction indicated by differential encoding direction information (e.g. bdpcm_dir_flag) obtained from the bitstream.
- the differential encoding direction information may indicate either a vertical direction or a horizontal direction.
- the image decoding apparatus may allocate a value obtained by adding the residual coefficient to be corrected and the predicted residual coefficient to the position of the residual coefficient to be corrected.
- the prediction residual coefficient may be a coefficient immediately before the residual coefficient to be corrected in an order according to the prediction direction.
- the decoding apparatus may calculate the quantized residual sample Q(r i, j ) by inversely performing the calculation previously performed by the encoding apparatus. For example, when the prediction direction of the BDPCM is the horizontal direction, the image decoding apparatus may generate a quantized residual block from the modified quantized residual block using Equation 17.
- the value Q(r i, j ) of the quantized residual sample of the (i, j) coordinate is modified quantized from the (0, j) coordinate to the (i, j) coordinate. It can be calculated by summing the values of the residual samples.
- the value Q(r i, j ) of the quantized residual sample of the (i, j) coordinate may be calculated using Equation 18 instead of Equation 17.
- Equation 18 is a reverse process corresponding to Equation 15.
- the value Q (r 0, j) of the quantized residual samples of the coordinate is (0, j)
- the Q(r i, j ) of the other (i, j) coordinates is the value of the modified quantized residual sample of the (i, j) coordinates r'i , j and the quantized of the (i-1, j) coordinates. It is derived as the sum of the residual samples Q(r i-1, j ).
- (i-1, j) coordinates quantized by the sum of the value of Q of the quantized residual samples (r i-1, j) by using the predicted value difference value r 'i, j residual sample values of the Q ( r i, j ) can be derived.
- the image decoding apparatus may generate a quantized residual block from the modified quantized residual block using Equation 19.
- the value Q(r i, j ) of the quantized residual sample of the (i, j) coordinate is modified quantized from the (i, 0) coordinate to the (i, j) coordinate. It can be calculated by summing the values of the residual samples.
- the value Q(r i, j ) of the quantized residual sample of the (i, j) coordinate may be calculated using Equation 20 instead of Equation 19.
- Equation 20 is a reverse process corresponding to Equation 16.
- (i, 0) a value Q of the quantized residual samples of the coordinate (r i, 0) is (i, 0) value of the modified quantized residual samples of coordinates r 'i, 0 Is guided by.
- the Q(r i, j ) of the other (i, j) coordinates is the value of the modified quantized residual sample of the (i, j) coordinates r'i , j and the quantized of the (i, j-1) coordinates. It is derived as the sum of the residual samples Q(r i, j-1 ).
- (i, j-1) quantized by summing up by using the value Q of the quantized residual samples (r i, j-1) as the predictive value difference value r 'i, j residual sample values of the coordinates Q ( r i, j ) can be derived.
- the image decoding apparatus When a quantized residual block composed of quantized residual samples is generated by performing step S3540 by the above-described method, the image decoding apparatus performs inverse quantization on the quantized residual block (S3550), You can create a residual block.
- BDPCM is applied, as described above, since the transform for the current block is skipped, the inverse transform for the inverse quantized residual block may be skipped.
- the image decoding apparatus may reconstruct the current block based on the prediction block generated in step S3520 and the residual block generated in step S3550 (S3560). For example, the image decoding apparatus may reconstruct the current block (the value of the restored sample) by adding the prediction block (the value of the predicted sample) and the residual block (the value of the residual sample). For example, a reconstructed sample value may be generated by adding the dequantized quantized sample Q -1 (Q(r i,j )) to the intra block prediction value. It indicates whether BDPCM is applied to the current block. Differential encoding mode information to be transmitted may be signaled through a bitstream.
- differential encoding direction information indicating the prediction direction of the BDPCM may be signaled through a bitstream.
- BDPCM is not applied to the current block, the differential encoding direction information may not be signaled.
- 36 to 38 are diagrams schematically showing syntax for signaling information about BDPCM.
- FIG. 36 is a diagram illustrating syntax of a sequence parameter set according to an embodiment for signaling BDPCM information.
- all SPS RBSPs included in at least one access unit (AU) having 0 as a temporal ID or provided through an external means can be used before they are referenced in the decoding process. Can be set.
- the SPS NAL unit including the SPS RBSP may be configured to have the same nuh_layer_id as the nuh_layer_id of the PPS NAL unit referring thereto.
- CVS all SPS NAL units having a specific sps_seq_parameter_set_id value may be set to have the same content.
- seq_parameter_set_rbsp() syntax of FIG. 36 sps_transform_skip_enable_flag described above and sps_bdpcm_enabled_flag described later are disclosed.
- the syntax element sps_bdpcm_enabled_flag may indicate whether intra_bdpcm_flag is provided in CU syntax for an intra coding unit.
- a first value (e.g. 0) of sps_bdpcm_enabled_flag may indicate that intra_bdpcm_flag is not provided in CU syntax for an intra coding unit.
- the second value (e.g. 1) of sps_bdpcm_enabled_flag may indicate that intra_bdpcm_flag may be provided in CU syntax for an intra coding unit.
- the value of sps_bdpcm_enabled_flag may be set to a first value (e.g. 0).
- a predetermined constraint condition in the encoding/decoding process may be signaled using the general_constraint_info() syntax.
- a syntax element no_bdpcm_constraint_flag indicating whether the value of sps_bdpcm_enabled_flag should be set to 0 may be signaled.
- a first value (e.g. 0) of no_bdpcm_constraint_flag may indicate that this limitation is not applied.
- the value of no_bdpcm_constraint_flag is the second value (e.g. 1)
- the value of sps_bdpcm_enabled_flag may be forced to the first value (e.g. 0).
- FIG. 38 is a diagram illustrating an embodiment of a coding unit() syntax for signaling information on BDPCM to a coding unit.
- the syntax elements intra_bdpcm_flag and intra_bdpcm_dir_flag may be signaled using the coding_unit() syntax.
- the syntax element intra_bdpcm_flag indicates whether BDPCM is applied to the current luma coding block located at (x0, y0). Can be indicated.
- a first value (e.g. 0) of intra_bdpcm_flag may indicate that BDPCM is not applied to the current luma coding block.
- the second value (e.g. 1) of intra_bdpcm_flag may indicate that BDPCM is applied to the current luma coding block.
- the intra_bdpcm_flag indicates that BDPCM is applied, and thus may indicate whether the transform is skipped and whether the intra luma prediction mode is performed by the intra_bdpcm_dir_flag described later.
- the syntax element intra_bdpcm_dir_flag may indicate the prediction direction of BDPCM.
- a first value (e.g. 0) of intra_bdpcm_dir_flag may indicate that the BDPCM prediction direction is a horizontal direction.
- the second value (e.g. 1) of intra_bdpcm_dir_flag may indicate that the BDPCM prediction direction is a vertical direction.
- a BDPCM residual coding method for lossless coding is disclosed.
- the value of transform_skip_flag may be derived as a second value (e.g. 1).
- the normal residual coding not the transform skip residual coding, may be applied to the chroma block of the current CU.
- the encoding device and the decoding device may set a value of transform_skip_flag to a second value (e.g. 1). Accordingly, residuals for performing transform skip residual coding on the luma component block of the current CU are signaled through the bitstream.
- a value of transform_skip_flag e.g. 1
- encoding using transform skip residual coding is not performed for the chroma component block, and encoding using normal residual coding is performed. Accordingly, different residual coding passes may be applied to the luma component block and the chroma component block belonging to the same CU, and thus, the coding rate may decrease.
- This problem can be solved by applying an integrated residual coding scheme to the luma component block and the chroma component block.
- an integrated residual coding scheme For example, in order to increase the coding rate for the BDPCM block, for a coding block to which BDPCM is applied, normal residual coding instead of transform skip residual coding may be used for both the luma component block and the chroma component block. This processing may be helpful to increase encoding efficiency, particularly when the lossless mode is applied as described above.
- the encoding apparatus needs to signal that normal residual coding is used for residual coding of a luma component block for a coding block to which BDPCM is applied.
- 39 is a diagram illustrating syntax of a TU for signaling a residual coding scheme selected for residual coding a luma component block.
- the syntax of FIG. 39 is changed to a condition 3910 for parsing transform_skip_flag compared to the TU syntax of FIG. 28.
- condition 3910 for parsing transform_skip_flag may further include a syntax element cu_transquant_bypass_flag to indicate whether a regular residual coding pass is applied for residual coding of a corresponding coding block.
- cu_transquant_bypass_flag may be referred to as a regular residual coding pass activation flag or a transform skip residual coding pass restriction flag (e.g. ts_residual_coding_disabled_flag) in that it indicates whether a regular residual coding pass is applied to the current coding block.
- the first value (e.g. 0) of cu_transquant_bypass_flag may indicate that transform skip residual coding can be applied for residual coding of a corresponding coding block.
- the second value (e.g. 1) of cu_transquant_bypass_flag may indicate that transform skip residual coding is not applied and regular residual coding is applied for residual coding of the corresponding coding block.
- the first value (e.g. 0) of cu_transquant_bypass_flag may indicate that quantization, transformation, and in-loop filter processes can be applied to the corresponding coding block.
- the second value (e.g. 1) of cu_transquant_bypass_flag may indicate that quantization, transform, and in-loop filter processes are bypassed for the corresponding coding block.
- the transform_skip_flag syntax element may be obtained from the bitstream. Accordingly, when BDPCM is applied to the current coding block or regular residual coding is applied for residual coding of the current coding block, the transform_skip_flag syntax element may not be obtained from the bitstream.
- the derivation of the transform_skip_flag value may be determined based on the value of cu_transquant_bypass_flag. For example, if the value of BdpcmFlag[x0][y0] described above is the second value (eg 1), and the value of cu_transquant_bypass_flag[x0][y0] is the first value (eg 0), transform_skip_flag[x0][ The value of y0] may be derived as a second value (eg 1). Accordingly, the residual coding of the luma component block of the current coding block may be performed according to a transform skip residual coding pass. For example, a syntax element for this may be a residual_ts_coding() syntax 3930 according to the syntax of FIG. 39 It can be obtained from the bitstream by
- the value of BdpcmFlag[x0][y0] is the first value (eg 0) or the value of cu_transquant_bypass_flag[x0][y0] is the second value (eg 1)
- the value of transform_skip_flag[x0][y0] is It can be derived as a first value (eg 0). Accordingly, residual coding of the luma component block of the current coding block may be performed according to a normal residual coding pass rather than a transform skip residual coding pass. For example, the syntax element for this may be obtained from the bitstream by the residual_coding() syntax 3920 according to the syntax of FIG. 39.
- transform_skip_flag in the syntax of FIG. 40 may be determined according to the following equation as described above with reference to FIG. 28, and only when the following equation is true, the transform_skip_flag syntax element can be obtained in the bitstream. have.
- transform_skip_flag when transform_skip_flag is not parsed in the bit stream, the value of transform_skip_flag is a value indicating transformation skip when BDPCM is applied, and when BDPCM is not applied, it is a value indicating whether or not transformation is applied is determined by another syntax element. Can be determined. For example, when the value of BdpcmFlag[x0][y0] is the second value (e.g. 1), the value of transform_skip_flag[x0][y0] may be derived as the second value (e.g. 1). Accordingly, transformation may not be applied to the corresponding coding block.
- the value of transform_skip_flag[x0][y0] may be derived as the first value (e.g. 0).
- the residual coding path determination condition 4020 of the luma component block of the current coding block may be determined based on values of transform_skip_flag[x0][y0] and cu_transquant_bypass_flag[x0][y0]. have. For example, if the value of transform_skip_flag[x0][y0] is the first value (eg 0) or the value of cu_transquant_bypass_flag[x0][y0] is the second value (eg 1), the normal residual coding path is the current coding block.
- a syntax element for performing a regular residual coding pass can be obtained from the bitstream using the residual_coding() syntax 4030.
- the transform skip residual coding pass is currently encoded. It can be applied to the block's luma component block.
- a syntax element for performing a transform skip residual coding pass may be obtained from the bitstream using the residual_ts_coding() syntax 4040.
- An image decoding apparatus includes a memory and a processor, and the decoding apparatus may perform decoding by an operation of the processor. For example, as illustrated in FIG. 41, the decoding apparatus may determine a residual coding method of a current transform block corresponding to the current coding block (S4110). Next, the decoding apparatus may restore residual information of the transform block based on the determined residual coding scheme (S4120). Next, the decoding apparatus may restore the current transform block based on the residual information (S4130). When block based delta pulse code modulation (BDPCM) is applied to the current coding block, the decoding apparatus may determine a residual coding scheme of the transform block based on whether transform skip residual coding can be performed on the current transform block.
- BDPCM block based delta pulse code modulation
- the decoding apparatus includes a flag indicating whether BDPCM is applied to the current coding block (eg BdpcmFlag) and a flag indicating whether normal residual coding is applied to the residual coding of the current coding block (eg cu_transquant_bypass_flag), the residual coding pass of the current coding block may be determined as either a normal residual coding pass or a transform skip residual coding pass.
- a flag indicating whether BDPCM is applied to the current coding block eg BdpcmFlag
- a flag indicating whether normal residual coding is applied to the residual coding of the current coding block eg cu_transquant_bypass_flag
- the decoding apparatus may determine a residual coding pass by determining a value of a transform skip flag (e.g. transform_skip_flag) indicating whether or not transformation is applied in the decoding process of the current coding block.
- a transform skip flag e.g. transform_skip_flag
- whether BDPCM is applied to the current coding block is signaled by a first flag (eg intra_bdpcm_flag)
- transform skip residual coding can be performed on the current transform block may be signaled by a second flag (eg cu_transquant_bypass_flag).
- the residual coding method of the transform block may be determined based on whether or not to skip the transform for the current transform block.
- whether or not the transform skip for the current transform block may be signaled by a transform skip flag (e.g. transform_skip_flag).
- the residual coding method of the current transform block may be determined as a regular residual coding method.
- the residual coding method of the current transform block is transform skip residual. It can be determined by a coding scheme.
- the residual coding method of the current transform block is a normal residual coding method. It can be determined by a coding scheme.
- the residual coding method of the current transform block may be determined as a regular residual coding method.
- the first flag indicates that BDPCM is not applied to the current coding block
- the transform for the current transform block is skipped
- the second flag indicates that the transform skip residual coding is not possible to perform in the current transform block
- the residual coding method of the current transform block may be determined as a regular residual coding method.
- the residual coding method is determined based on a transform skip flag indicating whether or not the transform skip of the current transform block, and the transform skip flag is obtained from the bitstream based on whether BDPCM is applied to the current coding block. Can be.
- the transform skip flag is not obtained from the bitstream, the value of the transform skip flag may be derived based on whether BDPCM is applied to the current coding block.
- the transform skip flag value may be derived by further considering whether transform skip residual coding can be performed in the current transform block. For example, if the value of the transform skip flag is derived, BDPCM is applied to the current coding block, and if transform skip residual coding is not possible to perform on the current transform block, the value of the transform skip flag is converted to the current transform block. It may be determined as a value indicating that it is not skipped. On the other hand, when the value of the transform skip flag is derived, if BDPCM is not applied to the current coding block or if transform skip residual coding can be performed on the current transform block, the value of the transform skip flag indicates that the transform is skipped in the current transform block. Can be determined by value.
- An image encoding apparatus includes a memory and a processor, and the encoding apparatus may perform encoding in a manner corresponding to decoding of the decoding apparatus by an operation of the processor. For example, as illustrated in FIG. 42, the encoding apparatus may determine a residual coding method of a current transform block corresponding to the current coding block (S4210). Next, the encoding apparatus may determine residual information of the current transform block based on the determined residual coding scheme (S4220). Next, the encoding apparatus may encode the current transform block based on the residual information (S4230). Here, when block based delta pulse code modulation (BDPCM) is applied to the current coding block, the coding apparatus may determine the residual coding method of the current transform block based on whether transform skip residual coding can be performed on the transform block. .
- BDPCM block based delta pulse code modulation
- the encoding apparatus may determine the residual coding pass of the current coding block as any one of a normal residual coding pass and a transform skip residual coding pass.
- the encoding apparatus performs a flag indicating whether BDPCM is applied to the current coding block (eg BdpcmFlag) and regular residual coding for the residual coding of the current coding block.
- a value of a flag indicating whether to be applied eg cu_transquant_bypass_flag
- a bitstream may be generated by encoding it.
- the encoding apparatus may encode a value of a transform skip flag (eg transform_skip_flag) indicating whether transformation is not applied in the decoding process of the current encoding block in order to signal the residual coding path applied to the current encoding block.
- the transform skip flag may be encoded based on BdpcmFlag and cu_transquant_bypass_flag as described above.
- whether BDPCM is applied to the current coding block is signaled by a first flag (eg intra_bdpcm_flag), and whether transform skip residual coding can be performed on the current transform block may be signaled by a second flag (eg cu_transquant_bypass_flag).
- the exemplary methods of the present disclosure are expressed as a series of operations for clarity of description, this is not intended to limit the order in which steps are performed, and each step may be performed simultaneously or in a different order if necessary.
- the exemplary steps may include additional steps, other steps may be included excluding some steps, or may include additional other steps excluding some steps.
- an image encoding apparatus or an image decoding apparatus performing a predetermined operation may perform an operation (step) of confirming an execution condition or situation of a corresponding operation (step). For example, when it is described that a predetermined operation is performed when a predetermined condition is satisfied, the video encoding apparatus or the video decoding apparatus performs an operation to check whether the predetermined condition is satisfied, and then performs the predetermined operation. I can.
- various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof.
- one or more ASICs Application Specific Integrated Circuits
- DSPs Digital Signal Processors
- DSPDs Digital Signal Processing Devices
- PLDs Programmable Logic Devices
- FPGAs Field Programmable Gate Arrays
- general purpose It may be implemented by a processor (general processor), a controller, a microcontroller, a microprocessor, or the like.
- the image decoding device and the image encoding device to which the embodiment of the present disclosure is applied include a multimedia broadcasting transmission/reception device, a mobile communication terminal, a home cinema video device, a digital cinema video device, a surveillance camera, a video chat device, and a real-time communication device such as video communication , Mobile streaming devices, storage media, camcorders, video-on-demand (VoD) service providers, OTT video (Over the top video) devices, Internet streaming service providers, three-dimensional (3D) video devices, video telephony video devices, and medical use. It may be included in a video device or the like, and may be used to process a video signal or a data signal.
- an OTT video (Over the top video) device may include a game console, a Blu-ray player, an Internet-connected TV, a home theater system, a smartphone, a tablet PC, and a digital video recorder (DVR).
- FIG. 43 is a diagram illustrating a content streaming system to which an embodiment of the present disclosure can be applied.
- a content streaming system to which an embodiment of the present disclosure is applied may largely include an encoding server, a streaming server, a web server, a media storage device, a user device, and a multimedia input device.
- the encoding server serves to generate a bitstream by compressing content input from multimedia input devices such as a smartphone, a camera, and a camcorder into digital data, and transmits it to the streaming server.
- multimedia input devices such as smart phones, cameras, camcorders, etc. directly generate bitstreams
- the encoding server may be omitted.
- the bitstream may be generated by an image encoding method and/or an image encoding apparatus to which an embodiment of the present disclosure is applied, and the streaming server may temporarily store the bitstream while transmitting or receiving the bitstream.
- the streaming server may transmit multimedia data to a user device based on a user request through a web server, and the web server may serve as an intermediary for notifying the user of a service.
- the web server transmits the request to the streaming server, and the streaming server transmits multimedia data to the user.
- the content streaming system may include a separate control server, and in this case, the control server may play a role of controlling a command/response between devices in the content streaming system.
- the streaming server may receive content from a media storage and/or encoding server. For example, when 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), a navigation system, a slate PC, and Tablet PC, ultrabook, wearable device, e.g., smartwatch, smart glass, head mounted display (HMD), digital TV, desktop There may be computers, digital signage, etc.
- PDA personal digital assistant
- PMP portable multimedia player
- Tablet PC ultrabook
- wearable device e.g., smartwatch, smart glass, head mounted display (HMD), digital TV, desktop
- HMD head mounted display
- digital TV desktop
- desktop There may be computers, digital signage, etc.
- Each server in the content streaming system may be operated as a distributed server, and in this case, data received from each server may be distributedly processed.
- the scope of the present disclosure is software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause an operation according to the method of various embodiments to be executed on a device or computer, and such software or It includes a non-transitory computer-readable medium (non-transitory computer-readable medium) which stores instructions and the like and is executable on a device or a computer.
- a non-transitory computer-readable medium non-transitory computer-readable medium
- An embodiment according to the present disclosure may be used to encode/decode an image.
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Compression Or Coding Systems Of Tv Signals (AREA)
Abstract
Description
MttSplitMode | mtt_split_cu_vertical_flag | mtt_split_cu_binary_flag |
SPLIT_TT_HOR | 0 | 0 |
SPLIT_BT_HOR | 0 | 1 |
SPLIT_TT_VER | 1 | 0 |
SPLIT_BT_VER | 1 | 1 |
Claims (15)
- 영상 복호화 장치에 의해 수행되는 영상 복호화 방법에 있어서,현재 부호화 블록에 대응되는 현재 변환 블록의 레지듀얼 코딩 방식을 결정하는 단계;상기 결정된 레지듀얼 코딩 방식에 기반하여 상기 변환 블록의 레지듀얼 정보를 복원하는 단계; 및상기 레지듀얼 정보에 기반하여 상기 현재 변환 블록을 복원하는 단계;를 포함하고,상기 현재 부호화 블록에 BDPCM(block based delta pulse code modulation)이 적용되는 경우, 상기 변환 블록의 레지듀얼 코딩 방식은 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능한지 여부에 기반하여 결정되는 영상 복호화 방법.
- 제 1 항에 있어서,상기 현재 부호화 블록에 BDPCM이 적용되는지 여부는 제 1 플래그에 의하여 시그널링 되고,상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능한지 여부는 제 2 플래그에 의하여 시그널링 되는 영상 복호화 방법.
- 제 2 항에 있어서,상기 제 1 플래그가 상기 현재 부호화 블록에 BDPCM이 적용되지 않음을 나타내는 경우, 상기 현재 변환 블록에 대한 변환 스킵 여부에 기반하여 상기 변환 블록의 레지듀얼 코딩 방식이 결정되고,상기 현재 변환 블록에 대한 변환 스킵 여부는 변환 스킵 플래그에 의하여 시그널링 되는 영상 복호화 방법.
- 제 2 항에 있어서,상기 제 2 플래그가 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능하지 않음을 나타내는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 정규 레지듀얼 코딩 방식으로 결정되는 영상 복호화 방법.
- 제 2 항에 있어서,상기 제 1 플래그가 상기 현재 부호화 블록에 BDPCM이 적용됨을 나타내고 상기 제 2 플래그가 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능함을 나타내는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 변환 스킵 레지듀얼 코딩 방식으로 결정되는 영상 복호화 방법.
- 제 2 항에 있어서,상기 제 1 플래그가 상기 현재 부호화 블록에 BDPCM이 적용됨을 나타내고, 상기 제 2 플래그가 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능하지 않음을 나타내는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 정규 레지듀얼 코딩 방식으로 결정되는 영상 복호화 방법.
- 제 2 항에 있어서,상기 제 1 플래그가 상기 현재 부호화 블록에 BDPCM이 적용되지 않음을 나타내고 상기 현재 변환 블록에 대한 변환이 스킵되지 않는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 정규 레지듀얼 코딩 방식으로 결정되는 영상 복호화 방법.
- 제 2 항에 있어서,상기 제 1 플래그가 상기 현재 부호화 블록에 BDPCM이 적용되지 않음을 나타내고, 상기 현재 변환 블록에 대한 변환이 스킵되며, 상기 제 2 플래그가 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능하지 않음을 나타내는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 정규 레지듀얼 코딩 방식으로 결정되는 영상 복호화 방법.
- 제 1 항에 있어서,상기 레지듀얼 코딩 방식은 상기 현재 변환 블록의 변환 스킵 여부를 나타내는 변환 스킵 플래그에 기반하여 결정되며,상기 변환 스킵 플래그는 상기 현재 부호화 블록에 BDPCM이 적용되는지 여부에 기반하여 비트스트림으로부터 획득되고,상기 변환 스킵 플래그가 비트스트림으로부터 획득되지 않는 경우, 상기 변환 스킵 플래그의 값은 상기 현재 부호화 블록에 BDPCM이 적용되는지 여부에 기반하여 유도되는 영상 복호화 방법.
- 제 9 항에 있어서,상기 변환 스킵 플래그의 값이 유도되는 경우, 상기 변환 스킵 플래그의 값은 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능한지 여부를 더 고려하여 유도되는 영상 복호화 방법.
- 제 10 항에 있어서,상기 변환 스킵 플래그의 값이 유도되고, 상기 현재 부호화 블록에 BDPCM이 적용되며, 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능하지 않은 경우, 상기 변환 스킵 플래그의 값은 상기 현재 변환 블록에 변환이 스킵되지 않음을 나타내는 값으로 결정되는 영상 복호화 방법.
- 제 10 항에 있어서,상기 변환 스킵 플래그의 값이 유도되고, 상기 현재 부호화 블록에 BDPCM이 적용되지 않거나 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능한 경우, 상기 변환 스킵 플래그의 값은 상기 현재 변환 블록에 변환이 스킵됨을 나타내는 값으로 결정되는 영상 복호화 방법.
- 메모리 및 적어도 하나의 프로세서를 포함하는 영상 복호화 장치로서,상기 적어도 하나의 프로세서는,현재 부호화 블록에 대응되는 현재 변환 블록의 레지듀얼 코딩 방식을 결정하고,상기 결정된 레지듀얼 코딩 방식에 기반하여 상기 현재 변환 블록의 레지듀얼 정보를 복원하며,상기 레지듀얼 정보에 기반하여 상기 현재 변환 블록을 복원하되,상기 현재 부호화 블록에 BDPCM(block based delta pulse code modulation)이 적용되는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 상기 현재 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능한지 여부에 기반하여 결정되는 영상 복호화 장치.
- 영상 부호화 장치에 의해 수행되는 영상 부호화 방법에 있어서,현재 부호화 블록에 대응되는 현재 변환 블록의 레지듀얼 코딩 방식을 결정하는 단계;상기 결정된 레지듀얼 코딩 방식에 기반하여 상기 현재 변환 블록의 레지듀얼 정보를 결정하는 단계; 및상기 레지듀얼 정보에 기반하여 상기 현재 변환 블록을 부호화하는 단계;를 포함하고,상기 현재 부호화 블록에 BDPCM(block based delta pulse code modulation)이 적용되는 경우, 상기 현재 변환 블록의 레지듀얼 코딩 방식은 상기 변환 블록에 변환 스킵 레지듀얼 코딩이 수행 가능한지 여부에 기반하여 결정되는 영상 부호화 방법.
- 제14항의 영상 부호화 방법에 의해 생성된 비트스트림을 전송하는 방법.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202080079782.6A CN114731435A (zh) | 2019-09-25 | 2020-09-25 | 用信号通知用于对应用bdpcm的块进行编码的残差编码方法的图像编码/解码方法和设备及发送比特流的方法 |
AU2020354148A AU2020354148B2 (en) | 2019-09-25 | 2020-09-25 | Image encoding/decoding method and apparatus for signaling residual coding method used for encoding block to which BDPCM is applied, and method for transmitting bitstream |
KR1020227009506A KR20220048478A (ko) | 2019-09-25 | 2020-09-25 | Bdpcm이 적용되는 부호화 블록에 이용되는 레지듀얼 코딩 방법을 시그널링하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 |
CA3156071A CA3156071A1 (en) | 2019-09-25 | 2020-09-25 | METHOD AND APPARATUS FOR CODING/DECODING A SIGNALING IMAGE OF A RESIDUAL ENCODING METHOD USED TO ENCODE A BLOCK TO WHICH A BDPCM IS APPLIED, AND METHOD FOR TRANSMITTING BITSTREAM |
MX2022003650A MX2022003650A (es) | 2019-09-25 | 2020-09-25 | Metodo y aparato de codificacion/decodificacion de imagen para se?alar el metodo de codificacion residual usado para codificar el bloque al cual se aplica bdpcm, y metodo para transmitir el flujo de bits. |
US17/703,696 US11638024B2 (en) | 2019-09-25 | 2022-03-24 | Image encoding/decoding method and apparatus for signaling residual coding method used for encoding block to which BDPCM is applied, and method for transmitting bitstream |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201962905400P | 2019-09-25 | 2019-09-25 | |
US62/905,400 | 2019-09-25 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/703,696 Continuation US11638024B2 (en) | 2019-09-25 | 2022-03-24 | Image encoding/decoding method and apparatus for signaling residual coding method used for encoding block to which BDPCM is applied, and method for transmitting bitstream |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2021060940A1 true WO2021060940A1 (ko) | 2021-04-01 |
Family
ID=75164883
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/KR2020/013150 WO2021060940A1 (ko) | 2019-09-25 | 2020-09-25 | Bdpcm이 적용되는 부호화 블록에 이용되는 레지듀얼 코딩 방법을 시그널링하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 |
Country Status (7)
Country | Link |
---|---|
US (1) | US11638024B2 (ko) |
KR (1) | KR20220048478A (ko) |
CN (1) | CN114731435A (ko) |
AU (1) | AU2020354148B2 (ko) |
CA (1) | CA3156071A1 (ko) |
MX (1) | MX2022003650A (ko) |
WO (1) | WO2021060940A1 (ko) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20180123466A (ko) * | 2010-07-16 | 2018-11-16 | 한국전자통신연구원 | 계층적 가변 블록 변환이 가능한 부호화 방법 및 장치 그리고 복호화 방법 및 장치 |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107820079B9 (zh) * | 2011-10-18 | 2021-09-21 | 株式会社Kt | 视频信号解码方法 |
EP4216546A1 (en) * | 2012-06-29 | 2023-07-26 | Electronics And Telecommunications Research Institute | Method for encoding/decoding images |
US11012701B2 (en) * | 2019-02-22 | 2021-05-18 | Tencent America LLC | Residual coding for transform skip mode and block differential pulse-code modulation |
US11350131B2 (en) * | 2019-06-28 | 2022-05-31 | Hfi Innovation Inc. | Signaling coding of transform-skipped blocks |
EP4000266A4 (en) * | 2019-08-20 | 2022-10-26 | Beijing Bytedance Network Technology Co., Ltd. | RESIDUAL CODING FOR TRANSFORM SKIP BLOCKS |
WO2021061318A1 (en) * | 2019-09-23 | 2021-04-01 | Alibaba Group Holding Limited | Lossless coding of video data |
-
2020
- 2020-09-25 KR KR1020227009506A patent/KR20220048478A/ko unknown
- 2020-09-25 CN CN202080079782.6A patent/CN114731435A/zh not_active Withdrawn
- 2020-09-25 CA CA3156071A patent/CA3156071A1/en active Pending
- 2020-09-25 WO PCT/KR2020/013150 patent/WO2021060940A1/ko active Application Filing
- 2020-09-25 MX MX2022003650A patent/MX2022003650A/es unknown
- 2020-09-25 AU AU2020354148A patent/AU2020354148B2/en active Active
-
2022
- 2022-03-24 US US17/703,696 patent/US11638024B2/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20180123466A (ko) * | 2010-07-16 | 2018-11-16 | 한국전자통신연구원 | 계층적 가변 블록 변환이 가능한 부호화 방법 및 장치 그리고 복호화 방법 및 장치 |
Non-Patent Citations (4)
Title |
---|
BENJAMIN BROSS , JIANLE CHEN , SHAN LIU: "Versatile Video Coding (Draft 6)", 127. MPEG MEETING; 20190708 - 20190712; GOTHENBURG; (MOTION PICTURE EXPERT GROUP OR ISO/IEC JTC1/SC29/WG11), no. JVET-O2001-v1, 13 July 2019 (2019-07-13), pages 1 - 406, XP030208555 * |
J. SOLE; R. JOSHI; M. KARCZEWICZ (QUALCOMM): "RCE2 Test A1: Simplified update of the coefficient level Rice parameter", 15. JCT-VC MEETING; 23-10-2013 - 1-11-2013; GENEVA; (JOINT COLLABORATIVE TEAM ON VIDEO CODING OF ISO/IEC JTC1/SC29/WG11 AND ITU-T SG.16 ); URL: HTTP://WFTP3.ITU.INT/AV-ARCH/JCTVC-SITE/, 15 October 2013 (2013-10-15), XP030115251 * |
M. KARCZEWICZ (QUALCOMM), M. COBAN (QUALCOMM): "CE8-related: Quantized residual BDPCM", 14. JVET MEETING; 20190319 - 20190327; GENEVA; (THE JOINT VIDEO EXPLORATION TEAM OF ISO/IEC JTC1/SC29/WG11 AND ITU-T SG.16 ), 24 March 2019 (2019-03-24), XP030204778 * |
XIN ZHAO , XIANG LI , XIAOZHONG XU , SHAN LIU: "CE7: Modified limitation on context coded bins for residual coding of Transform Skip mode (CE7-3.5 and CE7-3.6)", 15. JVET MEETING; 20190703 - 20190712; GOTHENBURG; (THE JOINT VIDEO EXPLORATION TEAM OF ISO/IEC JTC1/SC29/WG11 AND ITU-T SG.16 ), no. JVET-O0104-v2, 27 June 2019 (2019-06-27), pages 1 - 6, XP030218646 * |
Also Published As
Publication number | Publication date |
---|---|
AU2020354148B2 (en) | 2024-02-15 |
AU2020354148A1 (en) | 2022-04-14 |
CA3156071A1 (en) | 2021-04-01 |
KR20220048478A (ko) | 2022-04-19 |
US11638024B2 (en) | 2023-04-25 |
MX2022003650A (es) | 2022-05-10 |
CN114731435A (zh) | 2022-07-08 |
US20220279200A1 (en) | 2022-09-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2020180102A1 (ko) | 영상 코딩 시스템에서 컨텍스트 코딩된 사인 플래그를 사용하는 영상 디코딩 방법 및 그 장치 | |
WO2020251330A1 (ko) | 단순화된 mpm 리스트 생성 방법을 활용하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2020171592A1 (ko) | 영상 코딩 시스템에서 레지듀얼 정보를 사용하는 영상 디코딩 방법 및 그 장치 | |
WO2021101317A1 (ko) | 무손실 색상 변환을 이용한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2020213931A1 (ko) | 레지듀얼 계수의 차분 부호화를 이용한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021086020A1 (ko) | 색공간 변환을 이용한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2020251329A1 (ko) | Mip 모드 매핑이 단순화된 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2020251328A1 (ko) | 인트라 예측 모드 변환에 기반한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021086055A1 (ko) | 변환에 기반한 영상 코딩 방법 및 그 장치 | |
WO2021096290A1 (ko) | 변환에 기반한 영상 코딩 방법 및 그 장치 | |
WO2021172914A1 (ko) | 레지듀얼 코딩에 대한 영상 디코딩 방법 및 그 장치 | |
WO2021060844A1 (ko) | 팔레트 모드를 이용한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021054807A1 (ko) | 참조 샘플 필터링을 이용하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021060905A1 (ko) | 변환에 기반한 영상 코딩 방법 및 그 장치 | |
WO2020213976A1 (ko) | Bdpcm을 이용한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021172912A1 (ko) | 사인 데이터 하이딩 관련 영상 디코딩 방법 및 그 장치 | |
WO2021086021A1 (ko) | 적응적 변환을 이용한 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021015536A1 (ko) | 팔레트 모드의 적용 여부에 따라 디블로킹 필터링을 수행하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021054787A1 (ko) | 변환에 기반한 영상 코딩 방법 및 그 장치 | |
WO2021054783A1 (ko) | 변환에 기반한 영상 코딩 방법 및 그 장치 | |
WO2021006697A1 (ko) | 레지듀얼 코딩에 대한 영상 디코딩 방법 및 그 장치 | |
WO2021086023A1 (ko) | 적응적 변환을 이용하여 레지듀얼 처리를 수행하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021182816A1 (ko) | 직사각형 슬라이스의 크기 정보를 선택적으로 부호화 하는 영상 부호화/복호화 방법, 장치 및 비트스트림을 전송하는 방법 | |
WO2021201549A1 (ko) | 레지듀얼 코딩에 대한 영상 디코딩 방법 및 그 장치 | |
WO2021172916A1 (ko) | 영상 디코딩 방법 및 그 장치 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 20870029 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 20227009506 Country of ref document: KR Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 3156071 Country of ref document: CA |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 2020354148 Country of ref document: AU Date of ref document: 20200925 Kind code of ref document: A |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 20870029 Country of ref document: EP Kind code of ref document: A1 |