WO2020209478A1 - Method and device for partitioning picture into plurality of tiles - Google Patents

Abstract

A method by which a decoding device decodes an image, according to the present disclosure, comprises the steps of: receiving a bitstream including partitioning information about a current picture and prediction information about a current block included in the current picture; deriving a first partitioning structure, of the current picture, based on a plurality of tiles, on the basis of the partitioning information about the current picture, which includes information about the number of width parsing rows, information about a last width, information about the number of height parsing columns, and information about a last height; deriving prediction samples for the current block on the basis of the prediction information about the current block included in one of the plurality of tiles; and reconstructing the current picture on the basis of the prediction samples.

Description

Method and apparatus for dividing a picture into a plurality of tiles

The present disclosure relates to image coding technology, and more particularly, to a method and apparatus for dividing a picture into a plurality of tiles in an image coding system.

Recently, demand for high-resolution, high-quality video/video such as 4K or 8K or higher UHD (Ultra High Definition) video/video is increasing in various fields. As the video/video data becomes high-resolution and high-quality, the amount of information or bits to be transmitted increases relatively compared to the existing video/video data. When video/video data is stored by using it, the transmission cost and storage cost increase.

In addition, interest and demand for immersive media such as VR (Virtual Reality) and AR (Artificial Realtiy) contents or holograms are increasing in recent years, and videos/videos having different image characteristics from real images such as game images. Broadcasting about is increasing.

Accordingly, high-efficiency video/video compression technology is required in order to effectively compress, transmit, store, and reproduce information of high-resolution, high-quality video/video having various characteristics as described above.

It is an object of the present disclosure to provide a method and apparatus for increasing image coding efficiency.

Another technical problem of the present disclosure is to provide a method and apparatus for signaling partitioning information.

Another technical problem of the present disclosure is to provide a picture partitioning method and apparatus based on signaled information.

Another technical problem of the present disclosure is to provide a method and an apparatus for dividing a current picture based on dividing information for the current picture.

Another technical problem of the present disclosure is the width of each of length parsing skip tiles in which information about a width and a height is not parsed among a plurality of tiles constituting a current picture ( Or height), based on the last width (or height) of the signaled widths (or heights).

According to an embodiment of the present disclosure, a method of decoding an image performed by a decoding apparatus is provided. The method includes receiving a bitstream including partition information for a current picture and prediction information for a current block included in the current picture, a plurality of tiles The number of width parsing columns in which information about a width is parsed among a plurality of columns for deriving the first partitioning structure based on the first partitioning structure of the current picture based on) Information, information on the last width indicating the last parsed width among the widths of the width parsing columns, and the height among a plurality of rows for deriving the first split structure The above including information on the number of height parsing rows for which information is parsed, and information on a last height indicating a height parsed last among heights of the height parsing rows. Deriving based on the split information for a current picture, deriving prediction samples for the current block based on the prediction information for the current block included in one of the plurality of tiles, and Including the step of restoring the current picture based on the prediction samples, wherein the width of each of width parsing skip columns in which information about the width is not parsed among the plurality of columns is the last width The height of each of height parsing skip rows in which information about the height is not parsed among the plurality of rows is determined to be the last height.

According to another embodiment of the present disclosure, a decoding apparatus for performing image decoding is provided. The decoding apparatus receives a bitstream including split information on a current picture and prediction information on a current block included in the current picture, and generates a first split structure of the current picture based on a plurality of tiles, the Information on the number of width parsing columns from which information about the width is parsed among a plurality of columns for deriving the first partition structure, and the last parsed among the widths of the width parsing columns Information on the last width indicating the width, information on the number of height parsing rows from which height information among a plurality of rows for deriving the first partition structure is parsed And an entropy decoding unit for deriving based on the division information for the current picture including information on a last height indicating a height parsed last among heights of the height parsing rows, the plurality of A prediction unit for deriving prediction samples for the current block based on the prediction information for the current block included in one of tiles of, and an adder for reconstructing the current picture based on the prediction samples However, the width of each of the width parsing skip columns in which the information on the width is not parsed among the plurality of columns is determined as the last with write, and the information on the height among the plurality of rows is The height of each of height parsing skip rows that are not parsed is characterized in that all heights are determined as the last height.

According to another embodiment of the present disclosure, a video encoding method performed by an encoding device is provided. The method includes the steps of dividing a current picture into a plurality of tiles, width parsing columns in which information about a width among a plurality of columns for deriving the plurality of tiles is parsed based on the plurality of tiles ( information on the number of width parsing columns), information on the last width indicating the width parsed last among the widths of the width parsing columns, among a plurality of rows for deriving the plurality of tiles Information on the number of height parsing rows for which information about height is parsed, and a last height indicating the height parsed last among the heights of the height parsing rows. Generating split information for the current picture including information, deriving prediction samples for a current block included in one tile among the plurality of tiles, and for the current block based on the prediction samples Generating prediction information and encoding image information including split information on the current picture and prediction information on the current block, wherein information on the width among the plurality of columns is not parsed The width of each of the width parsing skip columns is the same as the last with write, and the height of each of the height parsing skip rows in which information about the height is not parsed among the plurality of rows is all the above. It features the same thing as the last height.

According to still another embodiment of the present disclosure, an encoding apparatus for performing image encoding is provided. The encoding apparatus may divide a current picture into a plurality of tiles, and based on the plurality of tiles, width parsing columns in which information about a width among a plurality of columns for deriving the plurality of tiles is parsed ( information on the number of width parsing columns), information on the last width indicating the width parsed last among the widths of the width parsing columns, among a plurality of rows for deriving the plurality of tiles Information on the number of height parsing rows for which information about height is parsed, and a last height indicating the height parsed last among the heights of the height parsing rows. An image segmentation unit that generates split information for the current picture including information, derives prediction samples for a current block included in one tile among the plurality of tiles, and calculates prediction samples for the current block based on the prediction samples. A prediction unit that generates prediction information for the current picture, and an entropy encoding unit that encodes image information including split information on the current picture and prediction information on the current block, wherein information on the width among the plurality of columns is parsed. The width of each of the width parsing skip columns is the same as the last width, and the height parsing skip rows from which information about the height is not parsed among the plurality of rows. All the heights are the same as the last height.

According to another embodiment of the present disclosure, there is provided a storage medium readable by a decoder that stores information on instructions that cause a video decoding apparatus to perform decoding methods according to some embodiments.

According to another embodiment of the present disclosure, there is provided a storage medium readable by a decoder that stores information on instructions that cause a video decoding apparatus to perform the decoding method according to the embodiment. The decoding method according to the embodiment includes: receiving a bitstream including partition information on a current picture and prediction information on a current block included in the current picture, a plurality of tiles Width parsing columns in which information about a width among a plurality of columns for deriving the first partitioning structure is parsed from a first partitioning structure of the current picture based on a plurality of tiles ( information on the number of width parsing columns), information on a last width representing the last parsed width among the widths of the width parsing columns, a plurality of rows for deriving the first split structure In the information on the number of height parsing rows in which information about the height is parsed, and the last height indicating the height parsed last among the heights of the height parsing rows Deriving based on the split information for the current picture including information about the current picture, based on the prediction information for the current block included in one of the plurality of tiles, predicting the current block A step of deriving samples and restoring the current picture based on the predicted samples, wherein the width of each of width parsing skip columns from among the plurality of columns in which information about the width is not parsed Is determined as the last with write, and height parsing skip rows in which information about the height is not parsed among the plurality of rows are all determined as the last height.

According to the present disclosure, it is possible to increase overall image/video compression efficiency.

According to the present disclosure, it is possible to increase the efficiency of picture partitioning.

According to the present disclosure, it is possible to increase the efficiency of picture partitioning based on segmentation information for a current picture.

According to the present disclosure, a width (or height) of each of length parsing skip tiles in which information about a width and a height is not parsed among a plurality of tiles constituting a current picture is signaled. By determining based on the last width (or height) of the set widths (or heights), it is possible to increase the efficiency of signaling for picture partitioning.

1 schematically shows an example of a video/video coding system to which the present disclosure can be applied.

2 is a diagram schematically illustrating a configuration of a video/video encoding apparatus to which the present disclosure can be applied.

3 is a diagram schematically illustrating a configuration of a video/video decoding apparatus to which the present disclosure can be applied.

4 is a flowchart illustrating a picture encoding procedure based on a tile and/or a tile group according to an embodiment.

5 is a flowchart illustrating a picture decoding procedure based on a tile and/or a tile group according to an embodiment.

6 is a diagram illustrating an example of dividing a picture into tiles.

7 is a block diagram illustrating a configuration of an encoding device according to an embodiment.

8 is a flowchart illustrating a configuration of a decoding apparatus according to an embodiment.

9 is a diagram illustrating an example of a tile and a tile group unit constituting a current picture.

10 is a diagram schematically illustrating an example of a signaling structure of tile group information.

11 is a flowchart illustrating an operation of an encoding device according to an embodiment.

12 is a block diagram illustrating a configuration of an encoding device according to another embodiment.

13 is a flowchart illustrating an operation of a decoding apparatus according to an embodiment.

14 is a block diagram illustrating a configuration of a decoding apparatus according to another embodiment.

15 shows an example of a content streaming system to which the disclosure of this document can be applied.

According to an embodiment of the present disclosure, a method of decoding an image performed by a decoding apparatus is provided. The method includes receiving a bitstream including partition information for a current picture and prediction information for a current block included in the current picture, a plurality of tiles The number of width parsing columns in which information about a width is parsed among a plurality of columns for deriving the first partitioning structure based on the first partitioning structure of the current picture based on) Information, information on the last width indicating the last parsed width among the widths of the width parsing columns, and the height among a plurality of rows for deriving the first split structure The above including information on the number of height parsing rows for which information is parsed, and information on a last height indicating a height parsed last among heights of the height parsing rows. Deriving based on the split information for a current picture, deriving prediction samples for the current block based on the prediction information for the current block included in one of the plurality of tiles, and Including the step of restoring the current picture based on the prediction samples, wherein the width of each of width parsing skip columns in which information about the width is not parsed among the plurality of columns is the last width The height of each of height parsing skip rows in which information about the height is not parsed among the plurality of rows is determined to be the last height.

In the present disclosure, various changes may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments. Terms commonly used in the present specification are used only to describe specific embodiments, and are not intended to limit the technical idea of the present disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other features or It is to be understood that the presence or addition of numbers, steps, actions, components, parts or combinations thereof does not preclude the possibility of preliminary exclusion.

Meanwhile, each of the components in the drawings described in the present disclosure is independently illustrated for convenience of description of different characteristic functions, and does not mean that each component is implemented as separate hardware or separate software. For example, two or more of the configurations may be combined to form one configuration, or one configuration may be divided into a plurality of configurations. Embodiments in which each configuration is integrated and/or separated are also included in the scope of the present disclosure unless departing from the essence of the disclosure.

This document is about video/image coding. For example, the method/embodiment disclosed in this document is a versatile video coding (VVC) standard, an essential video coding (EVC) standard, an AOMedia Video 1 (AV1) standard, a 2nd generation of audio video coding standard (AVS2), or a next-generation video/ It can be applied to a method disclosed in an image coding standard (ex. H.267 or H.268, etc.).

In this document, various embodiments related to video/image coding are presented, and the embodiments may be performed in combination with each other unless otherwise stated.

In this document, video may mean a set of images over time. A picture generally refers to a unit representing one image in a specific time period, and a slice/tile is a unit constituting a part of a picture in coding. A slice/tile may include one or more coding tree units (CTU). One picture may be composed of one or more slices/tiles. One picture may consist of one or more tile groups. One tile group may include one or more tiles. A brick may represent a rectangular region of CTU rows within a tile in a picture. A tile may be partitioned into multiple bricks, each of which consisting of one or more CTU rows within the tile. ). A tile that is not partitioned into multiple bricks may be also referred to as a brick. A brick scan may represent a specific sequential ordering of CTUs partitioning a picture, the CTUs may be arranged in a CTU raster scan within a brick, and bricks in a tile may be sequentially arranged in a raster scan of the bricks of the tile. And, tiles in a picture may be sequentially aligned by raster scan of the tiles of the picture (A brick scan is a specific sequential ordering of CTUs partitioning a picture in which the CTUs are ordered consecutively in CTU raster scan in a brick. , bricks within a tile are ordered consecutively in a raster scan of the bricks of the tile, and tiles in a picture are ordered consecutively in a raster scan of the tiles of the picture). A tile is a rectangular region of CTUs within a particular tile column and a particular tile row in a picture. The tile column is a rectangular region of CTUs, the rectangular region has a height equal to the height of the picture, and the width may be specified by syntax elements in a picture parameter set (The tile column is a rectangular region of CTUs having a height equal to the height of the picture and a width specified by syntax elements in the picture parameter set). The tile row is a rectangular region of CTUs, the rectangular region has a width specified by syntax elements in a picture parameter set, and a height may be the same as the height of the picture (The tile row is a rectangular region of CTUs having a height specified by syntax elements in the picture parameter set and a width equal to the width of the picture). A tile scan may represent a specific sequential ordering of CTUs that partition a picture, the CTUs may be sequentially arranged in a CTU raster scan in a tile, and tiles in a picture may be sequentially arranged in a raster scan of the tiles of the picture. (A tile scan is a specific sequential ordering of CTUs partitioning a picture in which the CTUs are ordered consecutively in CTU raster scan in a tile whereas tiles in a picture are ordered consecutively in a raster scan of the tiles of the picture). A slice may include an integer number of bricks of a picture, and the integer number of bricks may be included in one NAL unit (A slice includes an integer number of bricks of a picture that may be exclusively contained in a single NAL unit). A slice may consist of either a number of complete tiles or only a consecutive sequence of complete bricks of one tile. ). Tile groups and slices can be used interchangeably in this document. For example, in this document, the tile group/tile group header may be referred to as a slice/slice header.

A pixel or pel may mean a minimum unit constituting one picture (or image). In addition,'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.

A 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. One unit may include one luma block and two chroma (ex. cb, cr) blocks. The unit may be used interchangeably with terms such as a block or an area depending on the case. In general, the MxN block may include samples (or sample arrays) consisting of M columns and N rows, or a set (or array) of transform coefficients.

Hereinafter, preferred embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Hereinafter, the same reference numerals are used for the same constituent elements in the drawings, and duplicate descriptions for the same constituent elements may be omitted.

1 schematically shows an example of a video/video coding system to which the present disclosure can be applied.

Referring to FIG. 1, a video/image coding system may include a first device (a source device) and a second device (a receiving device). The source device may transmit the encoded video/image information or data in a file or streaming form to the receiving device through a digital storage medium or a network.

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

The video source may acquire a video/image through a process of capturing, synthesizing, or generating a video/image. The video source 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. For example, 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 encoding device may encode the input video/video. The encoding apparatus may perform a series of procedures such as prediction, transformation, and quantization for compression and coding efficiency. The encoded data (encoded video/video information) may be output in the form of a bitstream.

The transmission unit may transmit the encoded video/video information or data output in the form of a bitstream to the reception unit of the receiving device 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 may include an element for generating a media file through a predetermined file format, and may include an element for transmission through a broadcast/communication network. The receiver may receive/extract the bitstream and transmit it to the decoding device.

The decoding device may decode the video/image by performing a series of procedures such as inverse quantization, inverse transformation, and prediction corresponding to the operation of the encoding device.

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

2 is a diagram schematically illustrating a configuration of a video/video encoding apparatus to which the present disclosure can be applied. Hereinafter, the video encoding device may include an image encoding device.

2, the encoding device 200 includes an image partitioner 210, a predictor 220, a residual processor 230, an entropy encoder 240, and It may be configured to include an adder 250, a filter 260, and a memory 270. The prediction unit 220 may include an inter prediction unit 221 and an intra prediction unit 222. The residual processing unit 230 may include a transform unit 232, a quantizer 233, an inverse quantizer 234, and an inverse transformer 235. The residual processing unit 230 may further include a subtractor 231. The addition unit 250 may be referred to as a reconstructor or a recontructged block generator. The image segmentation unit 210, the prediction unit 220, the residual processing unit 230, the entropy encoding unit 240, the addition unit 250, and the filtering unit 260 described above may include one or more hardware components ( For example, it may be configured by an encoder chipset or a processor). In addition, the memory 270 may include a decoded picture buffer (DPB), and may be configured by a digital storage medium. The hardware component may further include the memory 270 as an internal/external component.

The image segmentation unit 210 may divide an input image (or picture, frame) input to the encoding apparatus 200 into one or more processing units. For example, the processing unit may be referred to as a coding unit (CU). In this case, the coding unit is recursively divided according to the QTBTTT (Quad-tree binary-tree ternary-tree) structure from a coding tree unit (CTU) or a largest coding unit (LCU). I can. For example, one coding unit may be divided into a plurality of coding units of a deeper depth based on a quad tree structure, a binary tree structure, and/or a ternary structure. In this case, for example, a quad tree structure may be applied first, and a binary tree structure and/or a ternary structure may be applied later. Alternatively, the binary tree structure may be applied first. The coding procedure according to the present disclosure may be performed based on the final coding unit that is no longer divided. In this case, based on the coding efficiency according to the image characteristics, the maximum coding unit can be directly used as the final coding unit, or if necessary, the coding unit is recursively divided into coding units of lower depth to be optimal. A coding unit of the size of may be used as the final coding unit. Here, the coding procedure may include a procedure such as prediction, transformation, and restoration described later. As another example, the processing unit may further include a prediction unit (PU) or a transform unit (TU). In this case, the prediction unit and the transform unit may be divided or partitioned from the above-described final coding unit, respectively. The prediction unit may be a unit of sample prediction, and 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 unit may be used interchangeably with terms such as a block or an area depending on the case. In general, the MxN block may represent a set of samples or transform coefficients consisting of M columns and N rows. In general, a sample may represent a pixel or a value of a pixel, may represent only a pixel/pixel value of a luminance component, or may represent only a pixel/pixel value of a saturation component. A sample may be used as a term corresponding to one picture (or image) as a pixel or pel.

The encoding apparatus 200 subtracts the prediction signal (predicted block, prediction sample array) output from the inter prediction unit 221 or the intra prediction unit 222 from the input video signal (original block, original sample array) to make a residual. A signal (residual signal, residual block, residual sample array) may be generated, and the generated residual signal is transmitted to the converter 232. In this case, as illustrated, a unit that subtracts the prediction signal (prediction block, prediction sample array) from the input image signal (original block, original sample array) in the encoder 200 may be referred to as a subtraction unit 231. The prediction unit may perform prediction on a block to be processed (hereinafter, referred to as a current block) and generate a predicted block including prediction samples for the current block. The prediction unit may determine whether intra prediction or inter prediction is applied in units of the current block or CU. The prediction unit may generate various information related to prediction, such as prediction mode information, as described later in the description of each prediction mode, and transmit it to the entropy encoding unit 240. The information on prediction may be encoded by the entropy encoding unit 240 and output in the form of a bitstream.

The intra prediction unit 222 may predict the current block by referring to samples in the current picture. The referenced samples may be located in the vicinity of the current block or may be located apart according to the prediction mode. In intra prediction, prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The 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 according to a detailed degree 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 222 may determine a prediction mode applied to the current block by using the prediction mode applied to the neighboring block.

The inter prediction unit 221 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. In this case, in order to reduce the amount of motion information transmitted in the inter prediction mode, 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. In the case of inter prediction, the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block 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. The temporal neighboring block may be called a collocated reference block, a co-located CU (colCU), and the like, and a reference picture including the temporal neighboring block may be referred to as a collocated picture (colPic). May be. For example, the inter prediction unit 221 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. For example, in the case of a skip mode and a merge mode, the inter prediction unit 221 may use motion information of a neighboring block as motion information of a current block. In the case of the skip mode, unlike the merge mode, a residual signal may not be transmitted. In the case of motion vector prediction (MVP) mode, the motion vector of the current block is calculated by using the motion vector of the neighboring block as a motion vector predictor and signaling a motion vector difference. I can instruct.

The prediction unit 220 may generate a prediction signal based on various prediction methods to be described later. For example, the prediction unit may apply intra prediction or inter prediction for prediction of one block, as well as simultaneously apply intra prediction and inter prediction. This can be called combined inter and intra prediction (CIIP). In addition, the prediction unit may be based on an intra block copy (IBC) prediction mode or a palette mode to predict a block. The IBC prediction mode or the palette mode may be used for content image/video coding such as a game, for example, screen content coding (SCC). IBC basically performs prediction in the current picture, but can be performed similarly to inter prediction in that it derives a reference block in the current picture. That is, the IBC may use at least one of the inter prediction techniques described in this document. The palette mode can be viewed as an example of intra coding or intra prediction. When the palette mode is applied, a sample value in a picture may be signaled based on information about a palette table and a palette index.

The prediction signal generated through the prediction unit (including the inter prediction unit 221 and/or the intra prediction unit 222) may be used to generate a reconstructed signal or may be used to generate a residual signal. The transform unit 232 may generate transform coefficients by applying a transform technique to the residual signal. For example, 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). Can include. Here, 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. In addition, the conversion process may be applied to a pixel block having the same size of a square, or may be applied to a block of variable size other than a square.

The quantization unit 233 quantizes the transform coefficients and transmits it to the entropy encoding unit 240, and the entropy encoding unit 240 encodes the quantized signal (information on quantized transform coefficients) and outputs it as a bitstream. have. The information on the quantized transform coefficients may be called residual information. The quantization unit 233 may rearrange the quantized transform coefficients in the form of blocks 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 240 may perform various encoding methods such as exponential Golomb, context-adaptive variable length coding (CAVLC), and context-adaptive binary arithmetic coding (CABAC). The entropy encoding unit 240 may encode together or separately information necessary for video/image reconstruction (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 format 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). In addition, the video/video information may further include general constraint information. In this document, information and/or syntax elements transmitted/signaled from the encoding device to the decoding device may be included in the video/video information. The video/video information 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. Here, the network may include a broadcasting network and/or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD. For the signal output from the entropy encoding unit 240, a transmission unit (not shown) for transmitting and/or a storage unit (not shown) for storing may be configured as an internal/external element of the encoding apparatus 200, or the transmission unit It may be included in the entropy encoding unit 240.

The quantized transform coefficients output from the quantization unit 233 may be used to generate a prediction signal. For example, a residual signal (residual block or residual samples) may be restored by applying inverse quantization and inverse transform to the quantized transform coefficients through the inverse quantization unit 234 and the inverse transform unit 235. The addition unit 155 adds the reconstructed residual signal to the prediction signal output from the inter prediction unit 221 or the intra prediction unit 222 to obtain a reconstructed signal (restored picture, reconstructed block, reconstructed sample array). Can be created. When there is no residual for a block to be processed, such as when the skip mode is applied, the predicted block may be used as a reconstructed block. The addition unit 250 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.

Meanwhile, luma mapping with chroma scaling (LMCS) may be applied during picture encoding and/or reconstruction.

The filtering unit 260 may improve subjective/objective image quality by applying filtering to the reconstructed signal. For example, the filtering unit 260 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 270, specifically, the DPB of the memory 270. 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 260 may generate a variety of filtering information and transmit it to the entropy encoding unit 240 as described later in the description of each filtering method. The filtering information may be encoded by the entropy encoding unit 240 and output in the form of a bitstream.

The modified reconstructed picture transmitted to the memory 270 may be used as a reference picture in the inter prediction unit 221. When inter prediction is applied through this, the encoding device may avoid prediction mismatch between the encoding device 100 and the decoding device, and may improve encoding efficiency.

The memory 270 DPB may store the modified reconstructed picture for use as a reference picture in the inter prediction unit 221. The memory 270 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 transferred to the inter prediction unit 221 in order to be used as motion information of spatial neighboring blocks or motion information of temporal neighboring blocks. The memory 270 may store reconstructed samples of reconstructed blocks in the current picture, and may be transmitted to the intra prediction unit 222.

3 is a diagram schematically illustrating a configuration of a video/video decoding apparatus to which the present disclosure can be applied.

Referring to FIG. 3, the decoding apparatus 300 includes an entropy decoder 310, a residual processor 320, a predictor 330, an adder 340, and a filtering unit. It may be configured to include (filter, 350) and memory (memoery) 360. The prediction unit 330 may include an inter prediction unit 331 and an intra prediction unit 332. The residual processing unit 320 may include a dequantizer 321 and an inverse transformer 321. The entropy decoding unit 310, the residual processing unit 320, the prediction unit 330, the addition unit 340, and the filtering unit 350 described above are one hardware component (for example, a decoder chipset or a processor). ) Can be configured. In addition, the memory 360 may include a decoded picture buffer (DPB), and may be configured by a digital storage medium. The hardware component may further include the memory 360 as an internal/external component.

When a bitstream including video/image information is input, the decoding apparatus 300 may reconstruct an image in response to a process in which the video/image information is processed by the encoding device of FIG. 3. For example, the decoding apparatus 300 may derive units/blocks based on block division related information obtained from the bitstream. The decoding device 300 may perform decoding using a processing unit applied in the encoding device. Thus, the processing unit of decoding may be, for example, a coding unit, and the coding unit may be divided from a coding tree unit or a maximum coding unit along a quad tree structure, a binary tree structure and/or a ternary tree structure. One or more transform units may be derived from the coding unit. In addition, the reconstructed image signal decoded and output through the decoding device 300 may be reproduced through the playback device.

The decoding apparatus 300 may receive a signal output from the encoding apparatus of FIG. 3 in the form of a bitstream, and the received signal may be decoded through the entropy decoding unit 310. For example, the entropy decoding unit 310 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). In addition, the video/video information may further include general constraint information. The decoding apparatus may further decode the picture based on the information on the parameter set and/or the general restriction information. Signaled/received information and/or syntax elements described later in this document may be decoded through the decoding procedure and obtained from the bitstream. For example, the entropy decoding unit 310 decodes information in the 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. In more detail, 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 and decoding information on a block to be decoded and a neighbor or a symbol/bin decoded in a previous step. A context model is determined using the context model, and a symbol corresponding to the value of each syntax element can be generated by performing arithmetic decoding of the bin by predicting the probability of occurrence of a bin according to the determined context model. have. In this case, 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. Among the information decoded by the entropy decoding unit 310, information about prediction is provided to a prediction unit (inter prediction unit 332 and intra prediction unit 331), and entropy decoding is performed by the entropy decoding unit 310. The dual value, that is, quantized transform coefficients and related parameter information may be input to the residual processing unit 320. The residual processing unit 320 may derive a residual signal (a residual block, residual samples, and a residual sample array). In addition, information about filtering among information decoded by the entropy decoding unit 310 may be provided to the filtering unit 350. Meanwhile, a receiver (not shown) for receiving a signal output from the encoding device may be further configured as an inner/outer element of the decoding device 300, or the receiver may be a component of the entropy decoding unit 310. Meanwhile, the decoding apparatus according to this document may be called a video/video/picture decoding apparatus, and the decoding apparatus can be divided into an information decoder (video/video/picture information decoder) and a sample decoder (video/video/picture sample decoder). May be. The information decoder may include the entropy decoding unit 310, and the sample decoder includes the inverse quantization unit 321, an inverse transform unit 322, an addition unit 340, a filtering unit 350, and a memory 360. ), an inter prediction unit 332 and an intra prediction unit 331 may be included.

The inverse quantization unit 321 may inverse quantize the quantized transform coefficients and output transform coefficients. The inverse quantization unit 321 may rearrange the quantized transform coefficients in a two-dimensional block shape. In this case, the rearrangement may be performed based on the coefficient scan order performed by the encoding device. The inverse quantization unit 321 may perform inverse quantization on quantized transform coefficients by using a quantization parameter (for example, quantization step size information) and obtain transform coefficients.

The inverse transform unit 322 obtains a residual signal (residual block, residual sample array) by inverse transforming the transform coefficients.

The prediction unit may perform prediction on the current block and generate a predicted block including prediction samples for the current block. The prediction unit may determine whether intra prediction or inter prediction is applied to the current block based on the information about the prediction output from the entropy decoding unit 310, and may determine a specific intra/inter prediction mode.

The prediction unit 320 may generate a prediction signal based on various prediction methods to be described later. For example, the prediction unit may apply intra prediction or inter prediction for prediction of one block, as well as simultaneously apply intra prediction and inter prediction. This can be called combined inter and intra prediction (CIIP). In addition, the prediction unit may be based on an intra block copy (IBC) prediction mode or a palette mode to predict a block. The IBC prediction mode or the palette mode may be used for content image/video coding such as a game, for example, screen content coding (SCC). IBC basically performs prediction in the current picture, but can be performed similarly to inter prediction in that it derives a reference block in the current picture. That is, the IBC may use at least one of the inter prediction techniques described in this document. The palette mode can be viewed as an example of intra coding or intra prediction. When the palette mode is applied, information about a palette table and a palette index may be included in the video/video information and signaled.

The intra prediction unit 331 may predict the current block by referring to samples in the current picture. The referenced samples may be located in the vicinity of the current block or may be located apart according to the prediction mode. In intra prediction, prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The intra prediction unit 331 may determine a prediction mode applied to the current block by using the prediction mode applied to the neighboring block.

The inter prediction unit 332 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. In this case, in order to reduce the amount of motion information transmitted in the inter prediction mode, 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. In the case of inter prediction, the neighboring block may include a spatial neighboring block existing in the current picture and a temporal neighboring block existing in the reference picture. For example, the inter prediction unit 332 may construct a motion information candidate list based on neighboring blocks, and derive a motion vector and/or a reference picture index of the current block based on the received candidate selection information. Inter prediction may be performed based on various prediction modes, and the information about the prediction may include information indicating a mode of inter prediction for the current block.

The addition unit 340 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 332 and/or the intra prediction unit 331). Signals (restored pictures, reconstructed blocks, reconstructed sample arrays) can be generated. When there is no residual for a block to be processed, such as when the skip mode is applied, the predicted block may be used as a reconstructed block.

The addition unit 340 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, may be output through filtering as described later, or may be used for inter prediction of the next picture.

Meanwhile, luma mapping with chroma scaling (LMCS) may be applied in the picture decoding process.

The filtering unit 350 may improve subjective/objective image quality by applying filtering to the reconstructed signal. For example, the filtering unit 350 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and the modified reconstructed picture may be converted to the memory 360, specifically, the DPB of the memory 360. Can be transferred to. The various filtering methods may include, for example, deblocking filtering, sample adaptive offset, adaptive loop filter, bilateral filter, and the like.

The (modified) reconstructed picture stored in the DPB of the memory 360 may be used as a reference picture in the inter prediction unit 332. The memory 360 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 360 may store reconstructed samples of reconstructed blocks in the current picture, and may be transmitted to the intra prediction unit 331.

In this specification, the embodiments described in the filtering unit 260, the inter prediction unit 221, and the intra prediction unit 222 of the encoding apparatus 100 are respectively the filtering unit 350 and the inter prediction of the decoding apparatus 300. The same or corresponding to the unit 332 and the intra prediction unit 331 may be applied.

As described above, prediction is performed to increase compression efficiency in performing video coding. Through this, a predicted block including prediction samples for a current block as a coding target block may be generated. Here, the predicted block includes prediction samples in the spatial domain (or pixel domain). The predicted block is derived equally from the encoding device and the decoding device, and the encoding device decodes information (residual information) about the residual between the original block and the predicted block, not the original sample value of the original block itself. Video coding efficiency can be improved by signaling to the device. The decoding apparatus may derive a residual block including residual samples based on the residual information, and generate a reconstructed block including reconstructed samples by summing the residual block and the predicted block. A reconstructed picture to be included can be generated.

The residual information may be generated through transformation and quantization procedures. For example, the encoding apparatus derives a residual block between the original block and the predicted block, and derives transform coefficients by performing a transformation procedure on residual samples (residual sample array) included in the residual block. And, by performing a quantization procedure on the transform coefficients, quantized transform coefficients may be derived, and related residual information may be signaled to a decoding apparatus (via a bitstream). Here, the residual information may include information such as value information of the quantized transform coefficients, position information, a transform technique, a transform kernel, and a quantization parameter. The decoding apparatus may perform an inverse quantization/inverse transform procedure based on the residual information and derive residual samples (or residual blocks). The decoding apparatus may generate a reconstructed picture based on the predicted block and the residual block. The encoding apparatus may also inverse quantize/inverse transform quantized transform coefficients for reference for inter prediction of a picture to derive a residual block, and generate a reconstructed picture based on this.

4 is a flowchart illustrating a picture encoding procedure based on a tile and/or a tile group according to an embodiment.

In the present specification, "tile" may mean a set of CTUs in a specific tile column and a rectangular region in a specific tile row in a picture. In one example, the tile may represent a set of bricks or a set of slices.

In the present specification, "slice" may mean a set of an integer number of bricks in a picture included in a single NAL unit. In one example, a slice may represent a set of tiles.

In the present specification, "brick" may represent CTU rows of a rectangular area included in a tile or slice in a picture.

However, in some embodiments, the meanings of the tile, slice, and brick may be used interchangeably. For those skilled in the art, the tiles, slices, and bricks are only for distinguishing units that divide the current picture, such as a first division unit, a second division unit, and a third division unit. It will be readily understood that there is no need to be interpreted strictly as limiting by definition.

In one embodiment, picture partitioning (S400) and generation of information on a tile/tile group (S410) may be performed by the image segmentation unit 210 of the encoding device, and a video including information on a tile/tile group /Encoding of image information (S420) may be performed by the entropy encoding unit 240 of the encoding device.

The encoding apparatus according to an embodiment may perform picture partitioning to encode an input picture (S400). The picture may include one or more tiles/tile groups. The encoding device may partition a picture into various types in consideration of the image characteristics and coding efficiency of the picture, and may generate information indicating a partitioning type having an optimal coding efficiency and signal the information to the decoding device.

The encoding apparatus according to an embodiment may determine a tile/tile group applied to the picture and generate information on the tile/tile group (S410). The information on the tile/tile group may include information indicating the structure of the tile/tile group for the picture. The information on the tile/tile group may be signaled through various parameter sets and/or tile group headers, as described later. A specific example will be described later.

The encoding apparatus according to an embodiment may encode video/video information including information on the tile/tile group and output it in the form of a bitstream (S420). The bitstream may be delivered to a decoding device through a digital storage medium or a network. The video/video information may include HLS and/or tile group header syntax described in this document. In addition, the video/video information may further include the above-described prediction information, residual information, (in-loop) filtering information, and the like. For example, the encoding apparatus may reconstruct the current picture, apply in-loop filtering, encode the parameter related to the in-loop filtering, and output a bitstream format.

Also, the information on the tile/tile group may further include information on a brick, as described later.

5 is a flowchart illustrating a picture decoding procedure based on a tile and/or a tile group according to an embodiment.

In one embodiment, obtaining information on a tile/tile group from a bitstream (S500), deriving a tile/tile group within a picture (S510), and performing picture decoding based on a tile/tile group ( S520) may be performed by the entropy decoding unit 310 of the decoding device, and the step of encoding video/video information including information on a tile/tile group (S530) may be performed by a sample decoder of the decoding device. I can.

The decoding apparatus according to an embodiment may obtain information on a tile/tile group from the received bitstream (S500). Information on the tile/tile group may be obtained through various parameter sets and/or tile group headers, as described later. A specific example will be described later. Also, the information on the tile/tile group may further include information on a brick, as described later.

The decoding apparatus according to an embodiment may derive a tile/tile group in a current picture based on the information on the tile/tile group (S510). In addition, the decoding apparatus may derive the brick.

The decoding apparatus according to an embodiment may decode the current picture based on the tile/tile group (S520). For example, the decoding apparatus may derive a brick/CTU/CU located in the tile, and based on this, perform inter/intra prediction, residual processing, reconstruction block (picture) generation, and/or in-loop filtering procedure. have. In addition, in this case, for example, the decoding device may initialize the context model/information on a tile/tile group basis. In addition, the decoding apparatus may process the neighboring block or the neighboring sample as not available when the neighboring block or neighboring sample referenced during inter/intra prediction is located in a tile different from the current tile in which the current block is located.

6 is a diagram illustrating an example of dividing a picture into tiles.

In this specification, specific terms or sentences are used to define specific information or concepts. For example, information on the number of height parsing rows from which height information is parsed among a plurality of rows for deriving a specific partition structure that divides the current picture into a plurality of tiles is represented as "num_tile_rows_minus1". , Information on the number of width parsing columns in which information about width is parsed among a plurality of columns for deriving a specific split structure for dividing the current picture into a plurality of tiles is indicated as "num_tile_columns_minus1", and the width The last parsed width among the widths of parsing columns is indicated as "last width", and the last parsed height among the heights of the height parsing rows is indicated as "last height".

However, "num_tile_rows_minus1" may be replaced with various terms such as num_exp_tile_rows_minus1, and "num_tile_columns_minus1" may be replaced with various terms such as num_exp_tile_columns_minus1, and the "last withth" may be replaced with last_width, LastWidth, etc. "" can be replaced with various terms such as last_height, LastHeight, etc., in interpreting a specific term or sentence used to define specific information or concept in this specification throughout the specification, the interpretation should not be limited to the name, and the above The term needs to be interpreted by paying attention to various actions, functions, and effects according to the content to be expressed.

In one embodiment, tiles may mean areas within a picture defined by a set of vertical and/or horizontal boundaries that divide the picture into a plurality of rectangles. FIG. 6 illustrates an example in which one picture 600 is divided into a plurality of tiles based on a plurality of column boundaries 610 and row boundaries 620. In FIG. 6, the first 32 maximum coding units (or Coding Tree Units (CTUs)) are numbered and shown.

In one embodiment, each tile may include an integer number of CTUs processed in a raster scan order within each tile. In this case, a plurality of tiles in a picture, including each tile, may also be processed in a raster scan order in the picture. The tiles may be grouped to form tile groups, and tiles within a single tile group may be raster scanned. Dividing a picture into tiles may be defined based on a syntax and semantics of a picture parameter set (PPS).

In one embodiment, the information derived from the PPS about the tiles may be used to check (or read) the following. First, it may be checked whether one tile exists or one or more tiles exist in a picture, and if one or more tiles are present, it may be checked whether the one or more tiles are uniformly distributed, and the tiles The dimension can be checked, and it can be checked whether the loop filter is enabled.

In an embodiment, the PPS may first signal the syntax element single_tile_in_pic_flag. The single_tile_in_pic_flag may indicate whether only one tile in a picture exists or whether there are a plurality of tiles in a picture. When there are a plurality of tiles in a picture, the decoding apparatus may parse information on the number of tile rows and tile columns using syntax elements num_tile_columns_minus1 and num_tile_rows_minus1. The syntax elements num_tile_columns_minus1 and num_tile_rows_minus1 may specify a process of dividing a picture into tile rows and columns. The heights of tile rows and widths of tile columns can be represented in terms of CTBs (ie, in CTB units).

In one embodiment, an additional flag may be parsed to check whether tiles within a picture are uniformly spaced. When the tiles in the picture are not uniformly spaced, the number of CTBs per tile may be explicitly signaled for the boundaries of each tile row and column (that is, the number of CTBs in each tile row and in each tile column). The number of CTBs can be signaled). If the tiles are uniformly spaced, the tiles may have the same width and height.

In one embodiment, another flag (eg, the syntax element loop_filter_across_tiles_enabled_flag) may be parsed to determine whether a loop filter is enabled for the tile boundaries. Table 1 below summarizes and shows examples of main information about tiles that can be derived by parsing the PPS. Table 1 may indicate the PPS RBSP syntax.

pic_parameter_set_rbsp(　) {	Descriptor
...
single_tile_in_pic_flag	u(1)
entropy_coding_sync_enabled_flag	u(1)
if( !single_tile_in_pic_flag) {
num_tile_columns_minus1	ue(v)
num_tile_rows_minus1	ue(v)
uniform_spacing_flag	u(1)
if( !uniform_spacing_flag) {
for( i = 0; i <num_tile_columns_minus1; i++)
column_width_minus1[　i　]	ue(v)
for( i = 0; i <num_tile_rows_minus1; i++)
row_height_minus1[　i　]	ue(v)
}
loop_filter_across_tiles_enabled_flag	u(1)
}
...	u(1)

Examples of semantics for syntax elements described in Table 1 may be, for example, as Table 2 below.

single_tile_in_pic_flag equal to 1 specifies that there is only one tile in each picture referring to the PPS. single_tile_in_pic_flag equal to 0 specifies that there is more than one tile in each picture referring to the PPS. It is a requirement of bitstream conformance that the value of single_tile_in_pic_flag shall be the same for all PPSs that are activated within a CVS.

num_tile_columns_minus1 plus 1 specifies the number of tile columns partitioning the picture. num_tile_columns_minus1 shall be in the range of 0 to PicWidthInCtbsY-1, inclusive. When not present, the value of num_tile_columns_minus1 is inferred to be equal to 0.

num_tile_rows_minus1 plus 1 specifies the number of tile rows partitioning the picture. num_tile_rows_minus1 shall be in the range of 0 to PicHeightInCtbsY-1, inclusive. When not present, the value of num_tile_rows_minus1 is inferred to be equal to 0.

The variable NumTilesInPic is set equal to (　num_tile_columns_minus1　+　1　)　*　(　num_tile_rows_minus1　+　1　).When single_tile_in_pic_flag is equal to 0, NumTilesInPic shall be greater than 1.

uniform_tile_spacing_flag equal to 1 specifies that tile column boundaries and likewise tile row boundaries are distributed uniformly across the picture. uniform_tile_spacing_flag equal to 0 specifies that tile column boundaries and likewise tile row boundaries are not distributed uniformly across the picture but signalled explicitly using the syntax elements tile_column_width_minus1[　i　] and tile_row_height_minus1[　i　]. When not present, the value of uniform_tile_spacing_flag is inferred to be equal to 1.

tile_column_width_minus1[　i　] plus 1 specifies the width of the i-th tile column in units of CTBs.

tile_row_height_minus1[　i　] plus 1 specifies the height of the i-th tile row in units of CTBs.

loop_filter_across_tiles_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across tile boundaries in pictures referring to the PPS. loop_filter_across_tiles_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across tile boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_tiles_enabled_flag is inferred to be equal to 1.

7 is a block diagram illustrating a configuration of an encoding device according to an embodiment, and FIG. 8 is a flowchart illustrating a configuration of a decoding device according to an embodiment.

7 shows an example of a block diagram of an encoding device. The encoding apparatus 700 illustrated in FIG. 7 includes a partitioning module 710 and an encoding module 720. The partitioning module 710 may perform the same and/or similar operations as the image segmentation unit 210 of the encoding apparatus shown in FIG. 2, and the encoding module 720 may perform the entropy of the encoding apparatus shown in FIG. 2. The same and/or similar operations as the encoding unit 240 may be performed. The input video may be segmented in the partitioning module 710 and then encoded in the encoding module 720. After being encoded, the encoded video may be output from the encoding device 700.

8 illustrates an example of a block diagram of a decoding device. The decoding apparatus 800 illustrated in FIG. 8 includes a decoding module 810 and a deblocking filter 820. The decoding module 810 may perform the same and/or similar operations as the entropy decoding unit 310 of the decoding apparatus shown in FIG. 3, and the deblocking filter 820 The same and/or similar operations as the filtering unit 350 may be performed. The decoding module 810 may derive information on tiles by decoding the input received from the encoding device 700. A processing unit may be determined based on the decoded information, and the deblocking filter 820 may process the processing unit by applying an in-loop deblocking filter. In-loop filtering can be applied to remove coding artifacts generated during the partitioning process. The in-loop filtering operation may include an adaptive loop filter (ALF), a deblocking filter (DF), a sample adaptive offset (SAO), and the like. Thereafter, the decoded picture may be output.

An example of a descriptor specifying the parsing process of each syntax element is disclosed in Table 3 below.

ae(v): context-adaptive arithmetic entropy-coded syntax element.

b(8): byte having any pattern of bit string (8　bits). The parsing process for this descriptor is specified by the return value of the function read_bits(　8　).

f(n): fixed-pattern bit string using n bits written (from left to right) with the left bit first. The parsing process for this descriptor is specified by the return value of the function read_bits(　n　).

i(n): signed integer using n bits. When n is "v" in the syntax table, the number of bits varies in a manner dependent on the value of other syntax elements. The parsing process for this descriptor is specified by the return value of the function read_bits(　n　) interpreted as a two's complement integer representation with most significant bit written first.

se(v): signed integer 0-th order Exp-Golomb-coded syntax element with the left bit first. The parsing process for this descriptor is specified with the order k equal to 0.

st(v): null-terminated string encoded as universal coded character set (UCS) transmission format-8 (UTF-8) characters as specified in ISO/IEC 10646.The parsing process is specified as follows: st(v) begins at a byte-aligned position in the bitstream and reads and returns a series of bytes from the bitstream, beginning at the current position and continuing up to but not including the next byte-aligned byte that is equal to 0x00, and advances the bitstream pointer by (　StringLength　+　1　)　*　8 bit positions, where stringLength is equal to the number of bytes returned.NOTE　-　The st(v) syntax descriptor is only used in this Specification when the current position in the bitstream is a byte-aligned position. tb(v): truncated binary using up to maxVal bits with maxVal defined in the semantics of the symtax element.

tu(v): truncated unary using up to maxVal bits with maxVal defined in the semantics of the symtax element.

u(n): unsigned integer using n bits. When n is "v" in the syntax table, the number of bits varies in a manner dependent on the value of other syntax elements. The parsing process for this descriptor is specified by the return value of the function read_bits(　n　) interpreted as a binary representation of an unsigned integer with most significant bit written first.

ue(v): unsigned integer 0-th order Exp-Golomb-coded syntax element with the left bit first. The parsing process for this descriptor is specified with the order k equal to 0.

uek(v): unsigned integer k-th order Exp-Golomb-coded syntax element with the left bit first. The parsing process for this descriptor is specified with the order k defined in the semantics of the symtax element.

9 is a diagram illustrating an example of a tile and a tile group unit constituting a current picture.

As described above, tiles can be grouped to form tile groups. 9 illustrates an example in which one picture is divided into tiles and tile groups. In FIG. 9, the picture includes 9 tiles and 3 tile groups. Each tile group can be independently coded.

10 is a diagram schematically illustrating an example of a signaling structure of tile group information.

Each tile group in the Coded Video Sequence (CVS) may include a tile group header. Tile groups may have a similar meaning to a slice group. Each tile group can be independently coded. A tile group may include one or more tiles. The tile group header may refer to the PPS, and the PPS may sequentially refer to a Sequence Parameter Set (SPS).

In FIG. 10, a tile group header may have a PPS index of a PPS referenced by the tile group header. The PPS may sequentially refer to the SPS.

In addition to the PPS index, the tile group header according to an embodiment may be determined for the following information. First, if there are more than one tile per picture, the tile group address and the number of tiles in the tile group may be determined. Next, a tile group type may be determined such as intra/predictive/bi-directional. Next, a picture order count (POC) of Lease Significant Bits (LSB) may be determined. Next, when more than one tile exists in one picture, an offset length and an entry point to the tile may be determined.

Table 4 below shows an example of the syntax of the tile group header.

tile_group_header(　) {	Descriptor
tile_group_pic_parameter_set_id	ue(v)
if( NumTilesInPic> 1) {
tile_group_address	u(v)
num_tiles_in_tile_group_minus1	ue(v)
}
tile_group_type	ue(v)
tile_group_pic_order_cnt_lsb	u(v)
if( partition_constraints_override_enabled_flag) {
partition_constraints_override_flag	ue(v)
...
if( num_tiles_in_tile_group_minus1> 0) {
offset_len_minus1	ue(v)
for( i = 0; i <num_tiles_in_tile_group_minus1; i++)
entry_point_offset_minus1[　i　]	u(v)
}
byte_alignment(　)
}

The following shows an example of English semantics for the syntax of the tile group header.

<English semantics for the syntax of tile group headers>

When present, the value of the tile group header syntax element tile_group_pic_parameter_set_id and tile_group_pic_order_cnt_lsb shall be the same in all tile group headers of a coded picture.

tile_group_pic_parameter_set_id specifies the value of pps_pic_parameter_set_id for the PPS in use. The value of tile_group_pic_parameter_set_id shall be in the range of 0 to 63, inclusive.

It is a requirement of bitstream conformance that the value of TemporalId of the current picture shall be greater than or equal to the value of TemporalId of the PPS that has pps_pic_parameter_set_id equal to tile_group_pic_parameter_set_id.

tile_group_address specifies the tile address of the first tile in the tile group, where tile address is the tile ID. The length of tile_group_address is Ceil( Log2 (NumTilesInPic)) bits. The value of tile_group_address shall be in the range of 0 to NumTilesInPic-1, inclusive, and the value of tile_group_address shall not be equal to the value of tile_group_address of any other coded tile group NAL unit of the same coded picture. When tile_group_address is not present it is inferred to be equal to 0.

num_tiles_in_tile_group_minus1 plus 1 specifies the number of tiles in the tile group. The value of num_tiles_in_tile_group_minus1 shall be in the range of 0 to NumTilesInPic-1, inclusive. When not present, the value of num_tiles_in_tile_group_minus1 is inferred to be equal to 0.

tile_group_type specifies the coding type of the tile group according to Table 5.

tile_group_type	Name of tile_group_type
0	B (B tile group)
One	P (P tile group)
2	I (I tile group)

When nal_unit_type is equal to IRAP_NUT, i.e., the picture is an IRAP picture, tile_group_type shall be equal to 2.

tile_group_pic_order_cnt_lsb specifies the picture order count modulo MaxPicOrderCntLsb for the current picture. The length of the tile_group_pic_order_cnt_lsb syntax element is log2_max_pic_order_cnt_lsb_minus4 + 4 bits. The value of the tile_group_pic_order_cnt_lsb shall be in the range of 0 to MaxPicOrderCntLsb-1, inclusive.

offset_len_minus1 plus 1 specifies the length, in bits, of the entry_point_offset_minus1[ i] syntax elements. The value of offset_len_minus1 shall be in the range of 0 to 31, inclusive.

entry_point_offset_minus1[ i] plus 1 specifies the i-th entry point offset in bytes, and is represented by offset_len_minus1 plus 1 bits. The tile group data that follow the tile group header consists of num_tiles_in_tile_group_minus1 +1 subsets, with subset index values ranging from 0 to num_tiles_in_tile_group_minus1, inclusive. The first byte of the tile group data is considered byte 0.When present, emulation prevention bytes that appear in the tile group data portion of the coded tile group NAL unit are counted as part of the tile group data for purposes of subset identification. Subset 0 consists of bytes 0 to entry_point_offset_minus1[ 0 ], inclusive, of the coded tile group data, subset k, with k in the range of 1 to num_tiles_in_tile_group_minus1-1, inclusive, consists of bytes firstByte[ k] to lastByte[ k] , inclusive, of the coded tile group data with firstByte[ k] and lastByte[ k] defined as:

The last subset (with subset index equal to num_tiles_in_tile_group_minus1) consists of the remaining bytes of the coded tile group data.

Each subset shall consist of all coded bits of all CTUs in the tile group that are within the same tile.

In one embodiment, the tile group may include a tile group header and tile group data. When the tile group address is known, individual positions of each CTU in the tile group may be mapped and decoded. Table 6 below shows an example of the syntax of tile group data.

tile_group_data(　) {	Descriptor
tileIdx = tile_group_address
for( i = 0; i <= num_tiles_in_tile_group_minus1; i++, tileIdx++) {
ctbAddrInTs = FirstCtbAddrTs[　tileIdx　]
for( j = 0; j <NumCtusInTile[　tileIdx　]; j++, ctbAddrInTs++) {
CtbAddrInRs = CtbAddrTsToRs[　ctbAddrInTs　]
coding_tree_unit(　)
}
end_of_tile_one_bit /* equal to 1 */	ae(v)
if( i <num_tiles_in_tile_group_minus1)
byte_alignment(　)
}
}

The following shows an example of English semantics for the syntax of the tile group data.

<English semantics for the syntax of tile group data>

Where the semantics are:

The list ColWidth[ i] for i ranging from 0 to num_tile_columns_minus1, inclusive, specifying the width of the i-th tile column in units of CTBs, is derived as follows:

if( uniform_tile_spacing_flag)

for( i = 0; i <= num_tile_columns_minus1; i++)

ColWidth[ i] = ((i + 1) * PicWidthInCtbsY) / (num_tile_columns_minus1 + 1)-

(i * PicWidthInCtbsY) / (num_tile_columns_minus1 + 1)

else {

ColWidth[ num_tile_columns_minus1] = PicWidthInCtbsY

for( i = 0; i <num_tile_columns_minus1; i++) {

ColWidth[ i] = tile_column_width_minus1[ i] + 1

ColWidth[ num_tile_columns_minus1] -= ColWidth[ i]

}

}

The list RowHeight[ j] for j ranging from 0 to num_tile_rows_minus1, inclusive, specifying the height of the j-th tile row in units of CTBs, is derived as follows:

if( uniform_tile_spacing_flag)

for( j = 0; j <= num_tile_rows_minus1; j++)

RowHeight[ j] = ((j + 1) * PicHeightInCtbsY) / (num_tile_rows_minus1 + 1)-

(j * PicHeightInCtbsY) / (num_tile_rows_minus1 + 1)

else {

RowHeight[ num_tile_rows_minus1] = PicHeightInCtbsY

for( j = 0; j <num_tile_rows_minus1; j++) {

RowHeight[ j] = tile_row_height_minus1[ j] + 1

RowHeight[ num_tile_rows_minus1] -= RowHeight[ j]

}

}

The list ColBd[ i] for i ranging from 0 to num_tile_columns_minus1 + 1, inclusive, specifying the location of the i-th tile column boundary in units of CTBs, is derived as follows:

for( ColBd[ 0] = 0, i = 0; i <= num_tile_columns_minus1; i++)

ColBd[ i + 1] = ColBd[ i] + ColWidth[ i]

The list RowBd[ j] for j ranging from 0 to num_tile_rows_minus1 + 1, inclusive, specifying the location of the j-th tile row boundary in units of CTBs, is derived as follows:

for( RowBd[ 0] = 0, j = 0; j <= num_tile_rows_minus1; j++)

RowBd[ j + 1] = RowBd[ j] + RowHeight[ j]

The list CtbAddrRsToTs[ ctbAddrRs] for ctbAddrRs ranging from 0 to PicSizeInCtbsY-1, inclusive, specifying the conversion from a CTB address in CTB raster scan of a picture to a CTB address in tile scan, is derived as follows:

for( ctbAddrRs = 0; ctbAddrRs <PicSizeInCtbsY; ctbAddrRs++) {

tbX = ctbAddrRs% PicWidthInCtbsY

tbY = ctbAddrRs / PicWidthInCtbsY

for( i = 0; i <= num_tile_columns_minus1; i++)

if( tbX >= ColBd[ i])

tileX = i

for( j = 0; j <= num_tile_rows_minus1; j++)

if( tbY >= RowBd[ j])

tileY = j

CtbAddrRsToTs[ ctbAddrRs] = 0

for( i = 0; i <tileX; i++)

CtbAddrRsToTs[ ctbAddrRs] += RowHeight[ tileY] * ColWidth[ i]

for( j = 0; j <tileY; j++)

CtbAddrRsToTs[ ctbAddrRs] += PicWidthInCtbsY * RowHeight[ j]

CtbAddrRsToTs[ ctbAddrRs] += (tbY-RowBd[ tileY]) * ColWidth[ tileX] + tbX-ColBd[ tileX]

}

The list CtbAddrTsToRs[ ctbAddrTs] for ctbAddrTs ranging from 0 to PicSizeInCtbsY-1, inclusive, specifying the conversion from a CTB address in tile scan to a CTB address in CTB raster scan of a picture, is derived as follows:

for( ctbAddrRs = 0; ctbAddrRs <PicSizeInCtbsY; ctbAddrRs++)

CtbAddrTsToRs[ CtbAddrRsToTs[ ctbAddrRs]] = ctbAddrRs

The list TileId[ ctbAddrTs] for ctbAddrTs ranging from 0 to PicSizeInCtbsY-1, inclusive, specifying the conversion from a CTB address in tile scan to a tile ID, is derived as follows:

for( j = 0, tileIdx = 0; j <= num_tile_rows_minus1; j++)

for( i = 0; i <= num_tile_columns_minus1; i++, tileIdx++)

for( y = RowBd[ j ]; y <RowBd[ j + 1 ]; y++)

for( x = ColBd[ i ]; x <ColBd[ i + 1 ]; x++)

TileId[ CtbAddrRsToTs[ y * PicWidthInCtbsY+ x]] = tileIdx

The list NumCtusInTile[ tileIdx] for tileIdx ranging from 0 to PicSizeInCtbsY-1, inclusive, specifying the conversion from a tile index to the number of CTUs in the tile, is derived as follows:

for( j = 0, tileIdx = 0; j <= num_tile_rows_minus1; j++)

for( i = 0; i <= num_tile_columns_minus1; i++, tileIdx++)

NumCtusInTile[ tileIdx] = ColWidth[ i] * RowHeight[ j]

The list FirstCtbAddrTs[ tileIdx] for tileIdx ranging from 0 to NumTilesInPic-1, inclusive, specifying the conversion from a tile ID to the CTB address in tile scan of the first CTB in the tile are derived as follows:

for( ctbAddrTs = 0, tileIdx = 0, tileStartFlag = 1; ctbAddrTs <PicSizeInCtbsY; ctbAddrTs++) {

if( tileStartFlag) {

FirstCtbAddrTs[ tileIdx] = ctbAddrTs

tileStartFlag = 0

}

tileEndFlag = ctbAddrTs = = PicSizeInCtbsY-1 | | TileId[ ctbAddrTs + 1] != TileId[ ctbAddrTs]

if( tileEndFlag) {

tileIdx++

tileStartFlag = 1

}

}

The values of ColumnWidthInLumaSamples[ i ], specifying the width of the i-th tile column in units of luma samples, are set equal to ColWidth[ i] << CtbLog2SizeY for i ranging from 0 to num_tile_columns_minus1, inclusive.

The values of RowHeightInLumaSamples[ j ], specifying the height of the j-th tile row in units of luma samples, are set equal to RowHeight[ j] << CtbLog2SizeY for j ranging from 0 to num_tile_rows_minus1, inclusive.

In one embodiment, in relation to the use case and application of tiles, there may be various application examples requiring picture division.

In one example, let's look at parallel processing. Implementations running on multi-core CPUs may require that the source picture be divided into tiles and tile groups. Each tile group can be processed in parallel on a separate core. The parallel processing can be beneficial for high resolution real-time encoding of videos. Additionally, the parallel processing may reduce information sharing between tile groups, thereby reducing memory constraints. Since tiles can be distributed to different threads during parallel processing, parallel architectures can benefit from this partitioning mechanism.

In another example, a maximum transmission unit (MTU) size matching will be examined. Coded pictures transmitted through a network may be subject to fragmentation when the coded pictures are larger than the MTU size. Similarly, when the coded segments are small, an Internet Protocol (IP) header may become important. Packet fragmentation may lead to loss of error resiliency. Dividing the picture into tiles and packing each tile/tile group into separate packets to mitigate the effects of packet fragmentation can give confidence that the packet is smaller than the MTU size.

In another example, let's look at error resilience. Error resilience may be motivated by the requirements of some applications that apply Unequal Error Protection (UEP) to coded tile groups.

In one embodiment, explicit uniform signaling for picture partitioning may be proposed. In other words, explicit signaling of information on tile columns and tile rows may be proposed for uniform spacing. Table 7 below shows an example of partially extracted syntax of the PPS level, and Table 8 below shows an example of semantics for the partially extracted syntax.

pic_parameter_set_rbsp(　) {	Descriptor
...
single_tile_in_pic_flag	u(1)
if( !single_tile_in_pic_flag) {
uniform_tile_spacing_flag	u(1)
if( uniform_tile_spacing_flag) {
tile_cols_width_minus1	ue(v)
tile_rows_height_minus1	ue(v)
} else {
num_tile_columns_minus1	ue(v)
num_tile_rows_minus1	ue(v)
for( i = 0; i <num_tile_columns_minus1; i++)
tile_column_width_minus1[　i　]	ue(v)
for( i = 0; i <num_tile_rows_minus1; i++)
tile_row_height_minus1[　i　]	ue(v)
}
...

single_tile_in_pic_flag equal to 1 specifies that there is only one tile in each picture referring to the PPS. single_tile_in_pic_flag equal to 0 specifies that there is more than one tile in each picture referring to the PPS.NOTE　-　In absence of further brick splitting within a tile, the whole tile is referred to as a brick. When a picture contains only a single tile without further brick splitting, it is referred to as a single brick.It is a requirement of bitstream conformance that the value of single_tile_in_pic_flag shall be the same for all PPSs that are activated within a CVS.

uniform_tile_spacing_flag equal to 1 specifies that tile column boundaries and likewise tile row boundaries are distributed uniformly across the picture and signalled using the syntax elements tile_cols_width_minus1 and tile_rows_height_minus1. uniform_tile_spacing_flag equal to 0 specifies that tile column boundaries and likewise tile row boundaries may or may not be distributed uniformly across the picture and signalled using the syntax elements num_tile_columns_minus1 and num_tile_rows_minus1 and a list of syntax element pairs tile_column_width_minus1[　i　1] and tile_row_minus1. When not present, the value of uniform_tile_spacing_flag is inferred to be equal to 1.

tile_cols_width_minus1 plus 1 specifies the width of the tile columns excluding the right-most tile column of the picture in units of CTBs when uniform_tile_spacing_flag is equal to 1.The value of tile_cols_width_minus1 shall be in the range of 0 to PicWidthInCtbsY-1, inclusive.

tile_rows_height_minus1 plus 1 specifies the height of the tile rows excluding the bottom tile row of the picture in units of CTBs when uniform_tile_spacing_flag is equal to 1.The value of tile_rows_height_minus1 shall be in the range of 0 to PicHeightInCtbsY-1, inclusive.

num_tile_columns_minus1 plus 1 specifies the number of tile columns partitioning the picture when uniform_tile_spacing_flag is equal to 0.The value of num_tile_columns_minus1 shall be in the range of 0 to PicWidthInCtbsY-1, inclusive. If single_tile_in_pic_flag is equal to 1, the value of num_tile_columns_minus1 is inferred to be equal to 0.Otherwise, when uniform_tile_spacing_flag is equal to 1, the value of num_tile_columns_minus1 is inferred.

num_tile_rows_minus1 plus 1 specifies the number of tile rows partitioning the picture when uniform_tile_spacing_flag is equal to 0.The value of num_tile_rows_minus1 shall be in the range of 0 to PicHeightInCtbsY-1, inclusive. If single_tile_in_pic_flag is equal to 1, the value of num_tile_rows_minus1 is inferred to be equal to 0.Otherwise, when uniform_tile_spacing_flag is equal to 1, the value of num_tile_rows_minus1 is inferred.The variable NumTilesInPic is inferred.The variable NumTilesInPic is inferred.The variable NumTilesInPic is inferred. +　1　).When single_tile_in_pic_flag is equal to 0, NumTilesInPic shall be greater than 1.

tile_column_width_minus1[　i　] plus 1 specifies the width of the i-th tile column in units of CTBs.

tile_row_height_minus1[　i　] plus 1 specifies the height of the i-th tile row in units of CTBs.

In an embodiment, when there are a plurality of tiles in a picture, a syntax element uniform_tile_spacing_flag indicating whether tiles having the same width and height are derived by uniformly dividing the picture may be parsed. The syntax element uniform_tile_spacing_flag may be used to indicate whether tiles within a picture are uniformly divided. When the syntax element uniform_tile_spacing_flag is enabled, the width of the tile column and the height of the tile row may be explicitly parsed. That is, the syntax element tile_cols_width_minus1 indicating the width of the tile column and the syntax element tile_rows_height_minus1 indicating the height of the tile row may be explicitly signaled and/or parsed.

In addition, syntax elements num_tile_columns_minus1 and num_tile_rows_minus1 may be signaled and/or parsed. The syntax element num_tile_columns_minus1 may indicate the number of explicitly signaled tile columns when dividing a picture into a plurality of tiles based on widths of explicitly signaled tile columns. Alternatively, the syntax element num_tile_columns_minus1 determines the number of explicitly signaled tile columns in dividing a partial region in a picture into a plurality of tiles based on the widths of tile columns for the explicitly signaled partial region. It can also be indicated. When the syntax element num_tile_columns_minus1 represents the number of tile columns whose width is signaled to divide a partial region in a picture into a plurality of tiles, the syntax element num_tile_columns_minus1 may be expressed as a syntax element num_exp_tile_columns_minus1.

Likewise, the syntax element num_tile_rows_minus1 may indicate the number of explicitly signaled tile rows when dividing a picture into a plurality of tiles based on the heights of explicitly signaled tile rows. Alternatively, the syntax element num_tile_rows_minus1 determines the number of explicitly signaled tile rows in dividing a partial region in a picture into a plurality of tiles based on the heights of tile rows for the explicitly signaled partial region. It can also be indicated. When the syntax element num_tile_rows_minus1 represents the number of tile columns whose height is signaled in order to divide a partial region in a picture into a plurality of tiles, the syntax element num_tile_rows_minus1 may be expressed as a syntax element num_exp_tile_rows_minus1.

In one embodiment, the num_exp_tile_columns_minus1 (or num_tile_columns_minus1) is information on the number of width parsing columns in which information about a width is parsed among a plurality of tile columns for deriving a tile division structure in a current picture. May represent an example of, and num_exp_tile_rows_minus1 (or num_tile_rows_minus1) is based on the number of height parsing rows in which information about height is parsed among a plurality of rows for deriving a tile division structure in the current picture. It may represent an example of information about. Information on the last width indicating the last parsed width among the widths of the width parsing columns may be expressed as tile_column_width_minus1 [num_exp_tile_columns_minus1] + 1 or tile_column_width_minus1 [num_tile_columns_minus1] + 1 based on Table 6. Information on the last height indicating the last parsed height among the heights of the height parsed rows may be expressed as tile_row_height_minus1 [num_exp_tile_rows_minus1] + 1 or tile_row_height_minus1 [num_tile_rows_minus1] + 1 based on Table 6.

In one example, the width of each of the width parsing skip columns in which the information on the width is not parsed among the plurality of columns is the last width (for example, the tile_column_width_minus1 [num_exp_tile_columns_minus1] + 1) or It is determined as tile_column_width_minus1 [num_tile_columns_minus1] + 1), and the height of each of height parsing skip rows in which information about the height is not parsed among the plurality of rows is the last height (for example, the tile_row_height_minus1 [ It may be determined as num_exp_tile_rows_minus1] + 1 or tile_row_height_minus1 [num_tile_rows_minus1] + 1). More specifically, uniform spacing may be applied to the widths of the width parsing skip columns and the heights of the height parsing skip rows. In other words, without parsing the uniform_tile_spacing_flag to determine whether to set the tile spacing uniformly, a tile splitting structure may be derived based on uniform spacing in some or all of the regions in the current picture. A person skilled in the art can easily derive the following Table 9, Equation 1, and Equation 2 from Table 7 based on this example.

pic_parameter_set_rbsp(　) {	Descriptor
...
no_pic_partition_flag	u(1)
if( !no_pic_partition_flag) {
pps_log2_ctu_size_minus5	u(2)
num_exp_tile_columns_minus1	ue(v)
num_exp_tile_rows_minus1	ue(v)
for( i = 0; i <= num_exp_tile_columns_minus1; i++)
tile_column_width_minus1[　i　]	ue(v)
for( i = 0; i <= num_exp_tile_rows_minus1; i++)
tile_row_height_minus1[　i　]	ue(v)

[Equation 1]

[Equation 2]

Referring to Table 9, num_exp_tile_columns_minus1 representing the number of width parsing columns and num_exp_tile_rows_minus1 representing the number of height parsing rows are parsed at the PPS level. You can see that this is parsed. Referring to Equation 1, it can be seen that tile_column_width_minus1[num_exp_tile_columns_minus1] representing the last withth represents the width of the uniform tile column (uniformTileColWidth). You can see that (uniformTileRowHeight) is displayed.

In an embodiment, after the process of dividing the picture into tiles is performed, the process of dividing the picture into bricks may be performed. First, a brick splitting process may be started based on brick_splitting_present_flag indicating whether one or more tiles of pictures referring to the PPS can be split into two or more bricks. Next, for each tile in the picture, a flag indicating whether the tile can be divided into bricks may be parsed. If the tile can be divided into bricks, it can be determined whether the tile can be uniformly divided. The uniform_brick_spacking_flag can be parsed, and when the uniform_brick_spacking_flag is enabled, the height of the brick row can be explicitly parsed. If the tiles are not uniformly divided, the height of each brick row may be parsed for each brick.

In addition, single_brick_per_slice_flag may be parsed. single_brick_per_slice_flag may indicate whether each slice referring to the PPS includes one brick. If each slice does not include one brick, the rectangular slice flag may be parsed. If the value of rect_slice_flag is 1 (or true) and a plurality of bricks exist in one slice, num_slices_in_pic_minus1 indicating the number of slices in a picture may be parsed. Next, for each slice in the picture, a difference between the index of the upper left brick and the index number and a delta corresponding to the difference may be parsed.

An example of the syntax representing the brick structure may be shown in Table 10 below, and an example of the semantics for the syntax representing the brick structure may be shown in Table 11 below.

pic_parameter_set_rbsp(　) {	Descriptor
pps_pic_parameter_set_id	ue(v)
pps_seq_parameter_set_id	ue(v)
single_tile_in_pic_flag	u(1)
if( !single_tile_in_pic_flag) {
uniform_tile_spacing_flag	u(1)
if( uniform_tile_spacing_flag) {
tile_cols_width_minus1	ue(v)
tile_rows_height_minus1	ue(v)
} else {
num_tile_columns_minus1	ue(v)
num_tile_rows_minus1	ue(v)
for( i = 0; i <num_tile_columns_minus1; i++)
tile_column_width_minus1[　i　]	ue(v)
for( i = 0; i <num_tile_rows_minus1; i++)
tile_row_height_minus1[　i　]	ue(v)
}
brick_splitting_present_flag	u(1)
for( i = 0; brick_present_flag && i <NumTilesInPic; i++) {
brick_split_flag[　i　]	u(1)
if( brick_split_flag[　i　]) {
uniform_brick_spacing_flag[　i　]	u(1)
if( uniform_brick_spacing_flag[　i　])
brick_rows_height_minus1[　i　]	ue(v)
else {
num_brick_rows_minus1[　i　]	ue(v)
for( j = 0; j <num_brick_rows_minus1[　i　]; j++)
brick_row_height_minus1[　i　][　j　]	ue(v)
}
}
}
single_brick_per_slice_flag	u(1)
if( !single_brick_per_slice_flag)
rect_slice_flag	u(1)
if( rect_slice_flag && !single_brick_per_slice_flag) {
num_slices_in_pic_minus1	ue(v)
for( i = 0; i <= num_slices_in_pic_minus1; i++) {
if( i> 0)
top_left_brick_idx[　i　]	u(v)
bottom_right_brick_idx_delta[　i　]	u(v)
}
}
loop_filter_across_bricks_enabled_flag	u(1)
if( loop_filter_across_bricks_enabled_flag)
loop_filter_across_slices_enabled_flag	u(1)
}
if( rect_slice_flag) {
signalled_slice_id_flag	u(1)
if( signalled_slice_id_flag) {
signalled_slice_id_length_minus1	ue(v)
for( i = 0; i <= num_slices_in_pic_minus1; i++)
slice_id[　i　]	u(v)
}
}
...
}

brick_splitting_present_flag equal to 1 specifies that one or more tiles of pictures referring to the PPS may be divided into two or more bricks. brick_splitting_present_flag equal to 0 specifies that no tiles of pictures referring to the PPS are divided into two or more bricks.

brick_split_flag[　i　] equal to 1 specifies that the i-th tile is divided into two or more bricks. brick_split_flag[　i　] equal to 0 specifies that the i-th tile is not divided into two or more bricks. When not present, the value of brick_split_flag[　i　] is inferred to be equal to 0.

uniform_brick_spacing_flag[　i　] equal to 1 specifies that brick row boundaries are distributed uniformly across the i-th tile and signalled using the syntax element brick_rows_height_minus1[　i　]. uniform_brick_spacing_flag[　i　] equal to 0 specifies that brick row boundaries may or may not be distributed uniformly across i-th tile and signalled using the syntax element num_brick_rows_minus1[　i　] and a list of syntax elements brick_row_height_minus1[　ji　][　i　]. When not present, the value of uniform_brick_spacing_flag[　i　] is inferred to be equal to 1.

brick_rows_height_minus1[　i　] plus 1 specifies the height of the brick rows excluding the bottom brick row in the i-th tile in units of CTBs when uniform_brick_spacing_flag[　i　] is equal to 1. When present, the value of brick_rows_height_minus1 shall be in the range of 0 to RowHeight[　i　]-2, inclusive.

num_brick_rows_minus1[　i　] plus 1 specifies the number of brick rows partitioning the i-th tile when uniform_brick_spacing_flag[　i　] is equal to 0. When present, the value of num_brick_rows_minus1[　i　] shall be in the range of 1 -1, inclusive. If brick_split_flag[　i　] is equal to 0, the value of num_brick_rows_minus1[　i　] is inferred to be equal to 0. Otherwise, when uniform_brick_spacing_flag[　i　] is equal to 1, the value of num_brick_rows_minus1[　i　] is inferi_rows.

brick_row_height_minus1[　i　][　j　] plus 1 specifies the height of the j-th brick row in the i-th tile in units of CTBs when uniform_tile_spacing_flag is equal to 0.The following variables are derived, and, when uniform_tile_spacing_flag is equal to 1, the values of num_tile_columns_minus1 and num_tile_rows_minus1 are inferred, and, for each i ranging from 0 to NumTilesInPic　-　1, inclusive, when uniform_brick_spacing_flag[　i　] is equal to 1, the value of the value of num_brick is equal to 1, the value of num_brick by num_brick raster and brick scanning conversion process:- the list RowHeight[　j　] for j ranging from 0 to num_tile_rows_minus1, inclusive, specifying the height of the j-th tile row in units of CTBs,- the list CtbAddrRsToBs[　ctbAddrRs　] for ctbAddrRs ranging from 0 to PicSizeInCtbsY　-　1, inclusive, specifying the conversion from a CTB address in the CTB raster scan of a picture to a CTB address in the brick scan,- the list CtbAddrBsToRs[　ctbAddrBs　] for ctbAddrBs ranging from 0 to PicS izeInCtbsY　-1, inclusive, specifying the conversion from a CTB address in the brick scan to a CTB address in the CTB raster scan of a picture,- the list BrickId[　ctbAddrBs　] for ctbAddrBs ranging from 0 to PicSizeInCtbsY　-1, inclusive, specifying the conversion from a CTB address in brick scan to a brick ID,- the list NumCtusInBrick[brickIdx　] for brickIdx ranging from 0 to NumBricksInPic　-　1, inclusive, specifying the conversion from a brick index to the number of CTUs in the brick,- the list FirstCtbAddrBs[　brickIdx　] for brickIdx ranging from 0 to NumBricksInPic　-1, inclusive, specifying the conversion from a brick ID to the CTB address in brick scan of the first CTB in the brick.

single_brick_per_slice_flag equal to 1 specifies that each slice that refers to this PPS includes one brick. single_brick_per_slice_flag equal to 0 specifies that a slice that refers to this PPS may include more than one brick. When not present, the value of single_brick_per_slice_flag is inferred to be equal to 1.

rect_slice_flag equal to 0 specifies that bricks within each slice are in raster scan order and the slice information is not signalled in PPS. rect_slice_flag equal to 1 specifies that bricks within each slice cover a rectangular region of the picture and the slice information is signalled in the PPS. When single_brick_per_slice_flag is equal to 1 rect_slice_flag is inferred to be equal to 1.

num_slices_in_pic_minus1 plus 1 specifies the number of slices in each picture referring to the PPS. The value of num_slices_in_pic_minus1 shall be in the range of 0 to NumBricksInPic　-　1, inclusive. When not present and single_brick_per_slice_flag is equal to 1, the value of num_slices_in_pic_minus1 is inferred to be equal to NumBricksInPic　-　1.

top_left_brick_idx[　i　] specifies the brick index of the brick located at the top-left corner of the i-th slice. The value of top_left_brick_idx[　i　] shall not be equal to the value of top_left_brick_idx[　j　] for any i not equal to j. When not present, the value of top_left_brick_idx[　i　] is inferred to be equal to i. The length of the top_left_brick_idx[　i　] syntax element is Ceil(　Log2(　NumBricksInPic　) bits.

bottom_right_brick_idx_delta[　i　] specifies the difference between the brick index of the brick located at the bottom-right corner of the i-th slice and top_left_brick_idx[　i　]. When single_brick_per_slice_flag is equal to 1, the value of bottom_right_brick_idx_delta[　i　] is inferred to be equal to 0. The length of the bottom_right_brick_idx_delta[　i　] syntax element is Ceil(　Log2(　　　) is inferred to be equal to 0. requirement of bitstream conformance that a slice shall include either a number of complete tiles or only a subset of one tile.The variable NumBricksInSlice[　i　] and BricksToSliceMap[　j　], which specify the number of bricks in the i-th slice and the mapping of bricks to slices, are derived as follows: NumBricksInSlice[　i　] = 0botRightBkIdx = top_left_brick_idx[　i　] + bottom_right_brick_idx_delta[　i　]for( j = 0; j <NumBricks[　d Bricks[　_Brick(LejBrick) {if_Colbrick(　) [i]] && BrickColBd [j] <= BrickColBd [botRightBkIdx] && BrickRowBd [j]> = BrickRowlBd [top_left_brick_idx [i]] && BrickRowBd [j] <= BrickColBd [botRightBkIdx]) {NumBricksInSlice [i] ++ BricksToSliceMap [ j　] = i }}

loop_filter_across_bricks_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across brick boundaries in pictures referring to the PPS. loop_filter_across_bricks_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across brick boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_bricks_enabled_flag is inferred to be equal to 1.

loop_filter_across_slices_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across slice boundaries in pictures referring to the PPS. loop_filter_across_slice_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across slice boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_slices_enabled_flag is inferred to be equal to 0.

signalled_slice_id_flag equal to 1 specifies that the slice ID for each slice is signalled. signalled_slice_id_flag equal to 0 specifies that slice IDs are not signalled. When rect_slice_flag is equal to 0, the value of signalled_slice_id_flag is inferred to be equal to 0.

signalled_slice_id_length_minus1 plus 1 specifies the number of bits used to represent the syntax element slice_id[　i　] when present, and the syntax element slice_address in slice headers. The value of signalled_slice_id_length_minus1 shall be in the range of 0 to 15, inclusive. When not present, the value of signalled_slice_id_length_minus1 is inferred to be equal to Ceil(　Log2(　num_slices_in_pic_minus1　+　1　)　)　-　1.

slice_id[　i　] specifies the slice ID of the i-th slice. The length of the slice_id[　i　] syntax element is signalled_slice_id_length_minus1　+　1 bits. When not present, the value of slice_id[　i　] is inferred to be equal to i, for each i in the range of 0 to num_slices_in_pic_minus1, inclusive.

The encoding device and/or the decoding device according to an embodiment may provide the current picture based on split information (eg, PPS information in Table 10), based on a plurality of tiles. A first partitioning structure of a picture can be derived.

The encoding device and/or the decoding device according to an embodiment may derive a second partition structure of the current picture based on a plurality of first partition units based on the partition information for the current picture. The third partition structure of the current picture may be derived based on the partition information of the current picture and based on a plurality of second partition units. In this case, one of the plurality of first divided units may be included in the one tile, may include the one tile, or be the same as the one tile. One of the plurality of second dividing units may be included in the one tile, the one tile, the first dividing unit, or the first dividing unit , It may be the same as the one tile.

In an embodiment, the partition information for the current picture may include a rectangular partition unit flag indicating whether the plurality of first partition units have a rectangular shape. The rectangular division unit flag may include rect_slice_flag of Table 9 above. The one first dividing unit may include at least one second dividing unit among the plurality of second dividing units. In one example, the first partitioning unit may be a slice, and the second partitioning unit may be a brick.

The encoding apparatus and/or the decoding apparatus according to an embodiment parses information on the total number of the plurality of first division units in the current picture based on a determination that the value of the rectangular first division unit flag is 1 The information on the index delta value of the at least one second partitioning unit included in the one first partitioning unit may be parsed. In one example, the index delta value may be bottom_right_brick_idx_delta in Table 9 above.

In an embodiment, the first partitioning unit may represent the same unit as a slice, and the second partitioning unit may represent the same unit as a tile. In another embodiment, the first partitioning unit may represent the same unit as a slice, and the second partitioning unit may represent the same unit as a brick. In another embodiment, the first division unit may represent the same unit as a tile, and the second division unit may represent the same unit as a brick.

11 is a flowchart illustrating an operation of an encoding device according to an embodiment, and FIG. 12 is a block diagram illustrating a configuration of an encoding device according to an embodiment.

The encoding apparatus according to FIGS. 11 and 12 may perform operations corresponding to the decoding apparatus according to FIGS. 13 and 14. Accordingly, operations of the decoding apparatus to be described later in FIGS. 13 and 14 may be similarly applied to the encoding apparatus according to FIGS. 11 and 12.

Each step disclosed in FIG. 11 may be performed by the encoding apparatus 200 disclosed in FIG. 2. More specifically, S1100 and S1110 may be performed by the image segmentation unit 210 disclosed in FIG. 2, S1120 and S1130 may be performed by the prediction unit 220 disclosed in FIG. 2, and S1140 is shown in FIG. 2. It may be performed by the disclosed entropy encoding unit 240. In addition, operations according to S1100 to S1140 are based on some of the contents described above in FIGS. 4 to 10. Accordingly, detailed descriptions overlapping with those described above in FIGS. 2 and 4 to 10 will be omitted or simplified.

As shown in FIG. 12, the encoding apparatus according to an embodiment may include an image segmentation unit 210, a prediction unit 220, and an entropy encoding unit 240. However, in some cases, not all of the components shown in FIG. 12 may be essential components of the encoding device, and the encoding device may be implemented by more or less components than the components shown in FIG. 12.

In the encoding apparatus according to an embodiment, the image segmentation unit 210, the prediction unit 220, and the entropy encoding unit 240 are each implemented as a separate chip, or at least two or more components are implemented through a single chip. It can also be implemented.

The encoding apparatus according to an embodiment may divide the current picture into a plurality of tiles (S1100). More specifically, the image dividing unit 210 of the encoding device may divide the current picture into a plurality of tiles.

The encoding apparatus according to an embodiment, based on the plurality of tiles, determines the number of width parsing columns in which information about a width is parsed among a plurality of columns for deriving the plurality of tiles. Information, information on a last width indicating a width to be parsed last among widths of the width parsing columns, information on a height among a plurality of rows for deriving the plurality of tiles The current picture including information on the number of height parsing rows to be parsed and a last height indicating a height parsed last among the heights of the height parsing rows Split information for may be generated (S1110). More specifically, the image segmentation unit 210 of the encoding apparatus includes information on the number of width parsing columns from which width information is parsed among a plurality of columns for deriving the plurality of tiles, based on the plurality of tiles, Information on the last withth representing the last parsed width among the widths of the width parsing columns, information on the number of height parsing rows from which height information among a plurality of rows for deriving the plurality of tiles is parsed, and the Split information for the current picture including information on the last height indicating the height parsed last among the heights of the height parsing rows may be generated.

The encoding apparatus according to an embodiment may derive prediction samples for a current block included in one of the plurality of tiles (S1120). More specifically, the prediction unit 220 of the encoding apparatus may derive prediction samples for a current block included in one of the plurality of tiles.

The encoding apparatus according to an embodiment may generate prediction information for the current block based on the prediction samples (S1130). More specifically, the prediction unit 220 of the encoding device may generate prediction information for the current block based on the prediction samples.

The encoding apparatus according to an embodiment may encode image information including segmentation information on the current picture and prediction information on the current block (S1140). More specifically, image information including split information on the current picture and prediction information on the current block may be encoded.

In one embodiment, the width of each of the width parsing skip columns in which the information about the width is not parsed among the plurality of columns is the same as the last with write, and the height of the plurality of rows is The height of each of height parsing skip rows for which information is not parsed may be the same as the last height.

In one embodiment, the total number of the width parsing skip columns and the height parsing skip rows is a sum of the columns of the width parsing columns, the sum of the heights of the height parsing rows, and the last It can be derived based on withth and the last height.

The encoding apparatus according to an embodiment may divide the current picture into a plurality of first segmentation units, and may divide the current picture into a plurality of second segmentation units.

In one embodiment, one of the plurality of first split units is included in the one tile, includes the one tile, is the same as the one tile, and is the plurality of second split units. One of the dividing units, one second dividing unit, is included in the one tile, included in the one tile, included in the first dividing unit, included in the first dividing unit, or included in the one tile Can be the same as

In an embodiment, the one first division unit may include at least one second division unit among the plurality of second division units.

The encoding apparatus according to an embodiment may encode information on the total number of the plurality of first partition units in the current picture, based on a determination that the plurality of first partition units are rectangular, and the one Information on the index delta value of the at least one second partitioning unit included in the first partitioning unit of may be encoded.

In an embodiment, the first split unit may represent the same unit as a slice, and the second split unit may represent the same unit as the one tile.

In one embodiment, the split information for the current picture may be encoded at the PPS level.

According to the encoding device of FIGS. 11 and 12 and the operating method of the encoding device, the encoding device divides a current picture into a plurality of tiles (S1100), and derives the plurality of tiles based on the plurality of tiles. Information on the number of width parsing columns in which information about the width is parsed among a plurality of columns, information on the last withth representing the last parsed width among the widths of the width parsing columns, and a plurality for deriving the plurality of tiles Split information for the current picture including information on the number of height parsed rows for which height information is parsed among the rows of and information on a last height indicating a height parsed last among the heights of the height parsed rows Generate (S1110), derive prediction samples for a current block included in one of the plurality of tiles (S1120), generate prediction information for the current block based on the prediction samples (S1130) , In step S1140, image information including split information for the current picture and prediction information for the current block may be encoded (S1140), and at this time, width parsing skip columns in which the information about the width is not parsed among the plurality of columns ( width parsing skip columns) Each width is the same as the last width, and the height of each of the height parsing skip rows in which information about the height is not parsed among the plurality of rows is the same as the last height. It can be characterized.

That is, according to the present disclosure, it is possible to increase the efficiency of picture partitioning. Also, according to the present disclosure, it is possible to increase the efficiency of picture partitioning based on split information for a current picture. In addition, according to the present disclosure, the width (or height) of each of length parsing skip tiles in which information about a width and a height is not parsed among a plurality of tiles constituting a current picture Is determined based on the last width (or height) of the signaled widths (or heights), it is possible to increase the efficiency of signaling for picture partitioning.

13 is a flowchart illustrating an operation of a decoding apparatus according to an embodiment, and FIG. 14 is a block diagram showing a configuration of a decoding apparatus according to an embodiment.

Each step disclosed in FIG. 13 may be performed by the decoding apparatus 300 disclosed in FIG. 3. More specifically, S1300 and S1310 may be performed by the entropy decoding unit 310 disclosed in FIG. 3, S1320 may be performed by the prediction unit 330 disclosed in FIG. 3, and S1330 is the addition disclosed in FIG. 3. It may be performed by the unit 340. In addition, operations according to S1300 to S1330 are based on some of the contents described above in FIGS. 4 to 10. Accordingly, detailed descriptions overlapping with those described above in FIGS. 3 to 10 will be omitted or simplified.

As shown in FIG. 14, the decoding apparatus according to an embodiment may include an entropy decoding unit 310, a prediction unit 330, and an addition unit 340. However, in some cases, not all of the components shown in FIG. 14 may be essential components of the decoding apparatus, and the decoding apparatus may be implemented by more or less components than those shown in FIG. 14.

In the decoding apparatus according to an embodiment, the entropy decoding unit 310, the prediction unit 330, and the addition unit 340 are each implemented as a separate chip, or at least two or more components are implemented through a single chip. It could be.

The decoding apparatus according to an embodiment may receive a bitstream including partition information on a current picture and prediction information on a current block included in the current picture (S1300). More specifically, the entropy decoding unit 310 of the decoding apparatus may receive a bitstream including split information on a current picture and prediction information on a current block included in the current picture. In one example, the splitting information includes information for splitting the current picture into a plurality of tiles, information for splitting the current picture into a plurality of slices, or information for splitting the current picture into a plurality of bricks. It may include at least one. The prediction information may include at least one of information on intra prediction for the current block, information on inter prediction, or information on Combined Inter Intra Prediction (CIIP).

The decoding apparatus according to an embodiment may determine a first partitioning structure of the current picture based on a plurality of tiles, and a width of a plurality of columns for deriving the first partitioning structure ( information on the number of width parsing columns for which information on width) is parsed, information on the last width indicating the last parsed width among the widths of the width parsing columns, At the end of the information on the number of height parsing rows from which information about the height is parsed among the plurality of rows for deriving the first partition structure, and heights of the height parsing rows It may be derived based on the segmentation information for the current picture including information on a last height indicating the height to be parsed (S1310). More specifically, the entropy decoding unit 310 of the decoding apparatus parses a first partition structure of the current picture based on a plurality of tiles, and information about a width among a plurality of columns for deriving the first partition structure. Information on the number of width parsing columns, information on the last width representing the last parsed width among the widths of the width parsing columns, information on the height of a plurality of rows for deriving the first partition structure are parsed It may be derived based on the segmentation information for the current picture including information on the number of height parsed rows and information on a last height indicating a height parsed last among the heights of the height parsed rows.

In one example, the information on the number of width parsing columns may be expressed as num_tile_columns_minus1 or num_exp_tile_columns_minus1, and the information on the last withth may be indicated by tile_column_width_minus1[num_tile_columns_minus1] or tile_column_width_minus1[num_tile_columns_minus1] or tile_column_width_minus1] for the height parsing rows. The information may be represented as num_tile_rows_minus1 or num_exp_tile_rows_minus1, and the information on the last withth may be represented as tile_row_height_minus1[num_tile_columns_minus1] or tile_row_height_minus1[num_exp_tile_columns_minus1].

The decoding apparatus according to an embodiment may derive prediction samples for the current block based on the prediction information for the current block included in one of the plurality of tiles (S1320). More specifically, the prediction unit 330 of the decoding apparatus may derive prediction samples for the current block based on the prediction information for the current block included in one of the plurality of tiles.

The decoding apparatus according to an embodiment may restore the current picture based on the predicted block (S1330). More specifically, the adder 340 of the decoding apparatus may restore the current picture based on the predicted block.

In one embodiment, the width of each of the width parsing skip columns in which information about the width is not parsed among the plurality of columns is determined as the last with write, and the height of the plurality of rows is The height of each of height parsing skip rows for which information about information is not parsed may be determined as the last height. In one example, the number of width parsing skip columns may be derived by subtracting the number of width parsing columns from the total number of other column columns, and the number of height parsing skip rows is the height from the total number of tile rows. It can be derived by subtracting the number of parsed rows.

In one embodiment, the total number of the width parsing skip columns and the height parsing skip rows is a sum of the columns of the width parsing columns, the sum of the heights of the height parsing rows, and the last It can be derived based on withth and the last height.

The decoding apparatus according to an embodiment may derive a second partition structure of the current picture based on a plurality of first partition units based on the partition information for the current picture, and the current picture A third partition structure of the current picture may be derived based on a plurality of second partition units based on the partition information for the picture. In this case, one of the plurality of first division units may be included in the one tile, the one tile, or the same as the one tile, and the plurality of second division units One of the units, the second division unit is included in the one tile, the one tile, the first division unit, the first division unit, or the one tile and Can be the same In one example, the first partitioning unit may be a slice, and the second partitioning unit may be a brick.

In an embodiment, the partition information for the current picture includes a rectangular first partition unit flag indicating whether the plurality of first partition units have a rectangular shape, The one first dividing unit may include at least one second dividing unit among the plurality of second dividing units. The decoding apparatus according to an embodiment may parse information on the total number of the plurality of first partition units in the current picture, based on a determination that the value of the rectangular first partition unit flag is 1, and the Information on the index delta value of the at least one second partitioning unit included in one first partitioning unit may be parsed. In one example, the index delta value may represent bottom_right_brick_idx_delta in Table 9 above.

In an example, when the first split unit represents the same unit as a slice, the rectangular first split unit flag may be represented by rect_slice_flag, and the total number of the plurality of first split units in the current picture The information may be represented by num_slices_in_pic_minus1.

In one embodiment, the first split unit may represent the same unit as a slice, and the second split unit may represent the same unit as the one tile. In another embodiment, the first partitioning unit may represent the same unit as a slice, and the second partitioning unit may represent the same unit as a brick. In another embodiment, the first division unit may represent the same unit as a tile, and the second division unit may represent the same unit as a brick.

In an embodiment, the split information for the current picture may be parsed at a picture parameter set (PPS) level.

According to the decoding apparatus and the operating method of the decoding apparatus disclosed in FIGS. 13 and 14, the decoding apparatus includes partition information on a current picture and prediction information on a current block included in the current picture. A first partitioning structure of the current picture based on a plurality of tiles is received (S1300) and a width among a plurality of columns for deriving the first partitioning structure Information on the number of width parsing columns for which information about (width) is parsed, information on the last width indicating the width parsed last among the widths of the width parsing columns , Information on the number of height parsing rows from which information on height is parsed among a plurality of rows for deriving the first partition structure, and the last of the heights of the height parsing rows The current block is derived based on the split information for the current picture including information on the last height indicating the height parsed in (S1310), and included in one tile among the plurality of tiles Based on the prediction information for, prediction samples for the current block may be derived (S1320), and the current picture may be reconstructed (S1330) based on the prediction samples, and at this time, the width of the plurality of columns Width parsing skip columns for which information about the width is not parsed are all determined as the last with write, and height parsing skip rows in which information about the height is not parsed among the plurality of rows Each height of skip rows) may be determined as the last height.

That is, according to the present disclosure, it is possible to increase the efficiency of picture partitioning. Also, according to the present disclosure, it is possible to increase the efficiency of picture partitioning based on split information for a current picture. In addition, according to the present disclosure, the width (or height) of each of length parsing skip tiles in which information about a width and a height is not parsed among a plurality of tiles constituting a current picture Is determined based on the last width (or height) of the signaled widths (or heights), it is possible to increase the efficiency of signaling for picture partitioning.

In the above-described embodiment, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present disclosure is not limited to the order of steps, and certain steps may occur in a different order or concurrently with the steps described above. have. In addition, those skilled in the art will appreciate that the steps shown in the flowchart are not exclusive, other steps are included, or one or more steps in the flowchart may be deleted without affecting the scope of the present disclosure.

In this document, "/" and "," are interpreted as "and/or". For example, "A/B" is interpreted as "A and/or B", and "A, B" is interpreted as "A and/or B". Additionally, “A/B/C” means “at least one of A, B and/or C”. In addition, "A, B, C" also means "at least one of A, B and/or C". (In this document, the term "/" and "," should be interpreted to indicate "and/or." For instance, the expression "A/B" may mean "A and/or B." Further, "A, B" may mean "A and/or B." Further, "A/B/C" may mean "at least one of A, B, and/or C." Also, "A/B/C" may mean " at least one of A, B, and/or C.")

Additionally, in this document "or" is interpreted as "and/or". For example, "A or B" may mean only 1) "A", 2) only "B", or 3) "A and B". In other words, "or" in this document may mean "additionally or alternatively". (Further, in the document, the term "or" should be interpreted to indicate "and/or." For instance, the expression "A or B" may comprise 1) only A, 2) only B, and/or 3) both A and B. In other words, the term "or" in this document should be interpreted to indicate "additionally or alternatively.")

The method according to the present disclosure described above may be implemented in the form of software, and the encoding device and/or the decoding device according to the present disclosure perform image processing such as a TV, a computer, a smart phone, a set-top box, a display device, etc. Can be included in the device.

In the present disclosure, when the embodiments are implemented as software, the above-described method may be implemented as a module (process, function, etc.) performing the above-described function. The modules are stored in memory and can be executed by the processor. The memory may be inside or outside the processor, and may be connected to the processor by various well-known means. The processor may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and/or a data processing device. The memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and/or other storage device. That is, the embodiments described in the present disclosure may be implemented and performed on a processor, microprocessor, controller, or chip. For example, the functional units illustrated in each drawing may be implemented and executed on a computer, processor, microprocessor, controller, or chip. In this case, information for implementation (ex. information on instructions) or an algorithm may be stored in a digital storage medium.

In addition, the decoding device and encoding device to which the present disclosure is applied include a multimedia broadcast transmission/reception device, a mobile communication terminal, a home cinema video device, a digital cinema video device, a surveillance camera, a video chat device, a real-time communication device such as video communication, and mobile streaming. 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, virtual reality (VR) devices, AR (argumente) reality) devices, video telephony video devices, transportation means terminals (ex.vehicle (including autonomous vehicles) terminals, airplane terminals, ship terminals, etc.) and medical video devices, and can be used to process video signals or data signals. I can. For example, 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).

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

In addition, an embodiment of the present disclosure may be implemented as a computer program product using a program code, and the program code may be executed in a computer by an embodiment of the present disclosure. The program code may be stored on a carrier readable by a computer.

15 shows an example of a content streaming system to which the disclosure of this document can be applied.

Referring to FIG. 15, a content streaming system to which 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 smartphones, cameras, camcorders, etc. into digital data, and transmits it to the streaming server. As another example, when multimedia input devices such as smartphones, cameras, camcorders, etc. directly generate bitstreams, the encoding server may be omitted.

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

The streaming server transmits multimedia data to a user device based on a user request through a web server, and the web server serves as an intermediary for notifying the user of a service. When a user requests a desired service from the web server, the web server transmits it to the streaming server, and the streaming server transmits multimedia data to the user. In this case, the content streaming system may include a separate control server, and in this case, the control server serves to control commands/responses 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, for example, smartwatch, smart glass, head mounted display (HMD)), digital TV, 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.

Claims (15)

1. In the video decoding method performed by the decoding device,

   Receiving a bitstream including partition information for a current picture and prediction information for a current block included in the current picture;

   A width at which information about a width among a plurality of columns for deriving the first partitioning structure is parsed from the first partitioning structure of the current picture based on a plurality of tiles Information on the number of width parsing columns, information on the last width indicating the last parsed width among the widths of the width parsing columns, and for deriving the first split structure A last height indicating information on the number of height parsing rows from which information about height among a plurality of rows is parsed, and a height that is parsed last among heights of the height parsing rows. deriving based on the segmentation information for the current picture including information on height);

   Deriving prediction samples for the current block based on the prediction information for the current block included in one of the plurality of tiles; And

   Including the step of restoring the current picture based on the prediction samples,

   The width of each of the width parsing skip columns in which the information about the width is not parsed among the plurality of columns is determined as the last with write, and the information about the height among the plurality of rows is not parsed. The height of each of height parsing skip rows, characterized in that all of the heights of the height parsing skip rows are determined as the last height.
2. The method of claim 1,

   The total number of the width parsing skip columns and the height parsing skip rows is the sum of the columns of the width parsing columns, the sum of the heights of the height parsing rows, the last withth and the last Characterized in that derived based on the height, video decoding method.
3. The method of claim 1,

   Deriving a second partition structure of the current picture based on a plurality of first partition units based on the partition information for the current picture; And

   Including the step of deriving a third partition structure of the current picture based on a plurality of second partition units (second partition units) based on the partition information on the current picture,

   One of the plurality of first split units is included in the one tile, includes the one tile, or is the same as the one tile,

   One of the plurality of second dividing units may be included in the one tile, the one tile, the first dividing unit, or the first dividing unit , The image decoding method, characterized in that the same as the one tile.
4. The method of claim 3,

   The partition information for the current picture includes a rectangular first partition unit flag indicating whether the plurality of first partition units have a rectangular shape,

   The one first dividing unit includes at least one second dividing unit among the plurality of second dividing units,

   The video decoding method,

   Parsing information on the total number of the plurality of first division units in the current picture based on a determination that the value of the rectangular first division unit flag is 1; And

   And parsing information on an index delta value of the at least one second partitioning unit included in the one first partitioning unit.
5. The method of claim 4,

   The first division unit represents the same unit as a slice,

   The second division unit, characterized in that representing the same unit as the one tile, video decoding method.
6. The method of claim 1,

   The split information on the current picture is parsed at a PPS (Picture Parameter Set) level.
7. The method of claim 1,

   The prediction information on the current block is parsed at a coding unit level.
8. In the video encoding method performed by the encoding device,

   Dividing the current picture into a plurality of tiles;

   Based on the plurality of tiles, information on the number of width parsing columns in which information about a width is parsed among a plurality of columns for deriving the plurality of tiles, and widths of the width parsing columns Information on the last width representing the width to be parsed at the end of (widths), height parsing in which information on the height among a plurality of rows for deriving the plurality of tiles is parsed generating segmentation information for the current picture including information on the number of rows) and information on a last height representing a height parsed last among heights of the height parsing rows;

   Deriving prediction samples for a current block included in one of the plurality of tiles;

   Generating prediction information for the current block based on the prediction samples; And

   Including the step of encoding image information including split information for the current picture and prediction information for the current block,

   The width of each of the width parsing skip columns in which the information on the width is not parsed among the plurality of columns is the same as the last width, and the information on the height among the plurality of rows is not parsed. The image encoding method, wherein the height of each of height parsing skip rows is the same as the last height.
9. The method of claim 8,

   The total number of the width parsing skip columns and the height parsing skip rows is the sum of the columns of the width parsing columns, the sum of the heights of the height parsing rows, the last withth and the last Characterized in that derived based on the height, video encoding method.
10. The method of claim 8,

    Dividing the current picture into a plurality of first division units; And

    Dividing the current picture into a plurality of second division units,

    One of the plurality of first split units is included in the one tile, includes the one tile, or is the same as the one tile,

    One of the plurality of second dividing units may be included in the one tile, the one tile, the first dividing unit, or the first dividing unit , The video encoding method, characterized in that the same as the one tile.
11. The method of claim 10,

    The one first dividing unit includes at least one second dividing unit among the plurality of second dividing units,

    The video encoding method,

    Encoding information on the total number of the plurality of first division units in the current picture, based on a determination that the plurality of first division units have a rectangular shape; And

    And encoding information on an index delta value of the at least one second partitioning unit included in the one first partitioning unit.
12. The method of claim 11,

    The first division unit represents the same unit as a slice,

    The second partitioning unit, characterized in that representing the same unit as the one tile.
13. The method of claim 8,

    The image encoding method, characterized in that the split information for the current picture is encoded at a PPS level.
14. The method of claim 8,

    The prediction information on the current block is encoded at a coding unit level.
15. In the decoding apparatus for performing video decoding,

    Receiving a bitstream including split information on a current picture and prediction information on a current block included in the current picture, and a first split structure of the current picture based on a plurality of tiles, and the first split structure Information on the number of width parsing columns from which information on width is parsed among a plurality of columns for derivation, and last with indicating the last parsed width among widths of the width parsing columns Information on the last width, information on the number of height parsing rows from which height information is parsed among a plurality of rows for deriving the first split structure, and the height parsing row An entropy decoding unit for deriving based on the split information for the current picture including information on a last height indicating a height parsed last among heights of the images;

    A prediction unit that derives prediction samples for the current block based on the prediction information for the current block included in one of the plurality of tiles; And

    Including an adder for reconstructing the current picture based on the prediction samples,

    The width of each of the width parsing skip columns in which the information about the width is not parsed among the plurality of columns is determined as the last with write, and the information about the height among the plurality of rows is not parsed. The decoding apparatus, characterized in that the height of each of height parsing skip rows is determined to be the last height.

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