WO2019045538A1 - Encoding method and apparatus therefor, and decoding method and apparatus therefor - Google Patents

Abstract

Provided is a video decoding method comprising the steps of: receiving a bitstream including a zone flag, a sub zone flag, and transform coefficient information of a current block; dividing the current block into a plurality of zones; determining which zone a last significant transform coefficient of the current block is included in among the plurality of zones, according to zone flags for the plurality of zones of the current block; dividing a zone in which at least one significant transform coefficient can be included, among the plurality of zones, into a plurality of sub zones; determining whether at least one significant transform coefficient is included in each of the plurality of sub zones, according to sub zone flags for the plurality of sub zones of the current block; determining a coefficient coding scheme for a sub zone including at least one significant transform coefficient, among the plurality of sub zones, on the basis of the zone flag and the sub zone flag; and acquiring an arrangement of transform coefficients of the current block by parsing the transform coefficient information of the current block according to the coefficient coding scheme.

Description

Coding method and apparatus, decoding method and apparatus thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present disclosure relates to a video encoding method and a video decoding method, and more particularly, to a method of efficiently encoding and decoding a transform coefficient.

High quality video requires a large amount of data when encoding. However, the bandwidth allowed for delivering video data is limited, so that the data rate applied when transmitting video data may be limited. Therefore, in order to efficiently transmit video data, a method of encoding and decoding video data with an increased compression ratio while minimizing deterioration of image quality is needed.

Video data can be compressed by eliminating spatial redundancy and temporal redundancy between pixels. Since it is common to have a common feature among adjacent pixels, encoding information is transmitted in units of data consisting of pixels in order to eliminate redundancy between adjacent pixels.

The pixel values of the pixels included in the data unit are not transmitted directly, but the necessary method to obtain the pixel value is transmitted. A prediction method for predicting the pixel value similar to the original value is determined for each data unit and the encoding information for the prediction method is transmitted from the encoder to the decoder. Also, since the predicted value is not exactly the same as the original value, the residual data of the difference between the original value and the predicted value is transmitted to the decoder in the encoder.

As the prediction becomes more accurate, the coding information required to specify the prediction method increases, but the size of the residual data decreases. Therefore, the prediction method is determined in consideration of the size of the encoding information and the residual data. In particular, data units divided in pictures have various sizes. The larger the size of a data unit, the more likely the prediction accuracy decreases, and the coding information decreases. Therefore, the size of the block is determined according to the characteristics of the picture.

The prediction methods include intra prediction and inter prediction. Intra prediction is a method of predicting pixels of a block from surrounding pixels of the block. Inter prediction is a method of predicting pixels with reference to pixels of another picture referenced by a picture including a block. Therefore, spatial redundancy is removed by intra prediction, and temporal redundancy is eliminated by inter prediction.

As the number of prediction methods increases, the amount of coding information to represent the prediction method increases. Therefore, the encoding information applied to the block can also be predicted from other blocks, thereby reducing the size of the encoded information.

 Since the loss of video data is allowed to the extent that the human vision can not recognize, the amount of residual data can be reduced by lossy compression of the residual data according to the transformation and quantization process.

A video encoding method and a video encoding apparatus for encoding a transform coefficient by dividing a current block into one or more regions and dividing the region into one or more sub-regions. Also disclosed are a video decoding method and a video decoding apparatus for decoding a transform coefficient by dividing a current block into one or more regions and dividing the region into one or more sub-regions. In addition, a computer-readable recording medium on which a program for causing a computer to execute a video encoding method and a video decoding method according to an embodiment of the present disclosure is disclosed.

Comprising the steps of: receiving a bitstream including a zone flag of a current block, a sub-zone flag, and transform coefficient information; dividing the current block into a plurality of zones; Determining which of the plurality of zones includes the last effective transform coefficient of the current block, determining a zone in which at least one effective transform coefficient of the plurality of zones may be included in a plurality of sub zones ), Determining, according to a sub-zone flag for a plurality of sub-zones of the current block, that at least one valid conversion coefficient is included for each of the plurality of sub-zones, Based on the at least one of the plurality of sub-zones, Determining a coefficient coding scheme for the current block, and acquiring a transform coefficient array of the current block by parsing the transform coefficient information of the current block according to the coefficient coding scheme, Method is provided.

The method comprising the steps of: receiving a bitstream including a zone flag of a current block, a subspace flag, and transform coefficient information, dividing the current block into a plurality of zones, and, in accordance with zone flags for a plurality of zones of the current block, Determining a zone in which the last effective conversion coefficient of the current block is included in the plurality of zones, dividing a zone into which the effective conversion coefficient of at least one of the plurality of zones may be included into a plurality of subareas, Determining, based on the sub-zone flag for the sub-zone of the plurality of sub-zones, at least one valid conversion coefficient for each of the plurality of sub-zones, and based on the zone flag and the sub- Determine the coefficient coding scheme for the subareas containing one effective transform coefficient And a processor for obtaining transform coefficient arrays of the current block by parsing transform coefficient information of the current block according to the coefficient coding scheme.

Determining a zone flag for a plurality of zones of the current block according to whether or not the last valid coefficient of the current block is included in a zone among the plurality of zones of the current block; Dividing a region into which the effective transform coefficients of at least one of the plurality of regions may be included into a plurality of sub-regions, determining whether at least one effective transform coefficient is included in each of the plurality of sub- Determining a sub-zone flag for a plurality of sub-zones of the current block, determining, based on the zone flag and the sub-zone flag, a coefficient for a sub-zone comprising at least one effective transform coefficient of the plurality of sub- Determining a coding scheme, determining a coding scheme of the current block according to the coefficient coding scheme, Determining a transform coefficient information of the current block from a transform coefficient array, and outputting a bit stream including the zone flag, the sub zone flag, and the transform coefficient information of the current block do.

Determining a zone flag for a plurality of zones of the current block according to whether one of a plurality of zones of the current block includes the last valid conversion coefficient of the current block, , Dividing a region into which at least one effective transform coefficient of the plurality of regions may be included into a plurality of sub-regions, and determining whether or not at least one effective transform coefficient is included in each of the plurality of sub- Determining a sub-zone flag for a plurality of sub-zones of the plurality of sub-zones based on the zone flag and the sub-zone flag, and determining a coefficient coding scheme for the sub- And transforming the transform coefficient array of the current block into a transform coefficient array according to the coefficient coding scheme, Determining a transform coefficient information of a current block, the video encoding apparatus including the current block of the flag area, the sub-area flag, and a processor for outputting a bit stream including the transform coefficient information is provided.

There is provided a computer-readable recording medium on which a program for performing the video coding method and the video decoding method is recorded.

The technical problem to be solved by this embodiment is not limited to the above-mentioned technical problems, and other technical problems can be deduced from the following embodiments.

The encoding and decoding efficiency of video coding and decoding is increased by encoding and decoding the transform coefficients of the current block according to various methods.

FIG. 1A shows a block diagram of an image encoding apparatus based on an encoding unit according to a tree structure according to an embodiment of the present disclosure.

FIG. 1B shows a block diagram of a video decoding method based on a coding unit according to a tree structure according to an embodiment.

FIG. 2 illustrates a process in which an image decoding apparatus determines at least one encoding unit by dividing a current encoding unit according to an embodiment.

FIG. 3 illustrates a process in which an image decoding apparatus determines at least one encoding unit by dividing a non-square encoding unit according to an embodiment.

FIG. 4 illustrates a process in which an image decoding apparatus divides an encoding unit based on at least one of division type mode information according to an embodiment.

FIG. 5 illustrates a method for an image decoding apparatus to determine a predetermined encoding unit among an odd number of encoding units according to an embodiment.

FIG. 6 illustrates a sequence in which a plurality of encoding units are processed when an image decoding apparatus determines a plurality of encoding units by dividing a current encoding unit according to an exemplary embodiment.

FIG. 7 illustrates a process for determining that the current encoding unit is divided into odd number of encoding units when the image decoding apparatus can not process the encoding units in a predetermined order according to an exemplary embodiment.

FIG. 8 illustrates a process in which an image decoding apparatus determines at least one encoding unit by dividing a first encoding unit according to an embodiment.

9 is a diagram illustrating a case where the second encoding unit is limited in the case where the second encoding unit of the non-square type determined by dividing the first encoding unit satisfies a predetermined condition according to an embodiment of the present invention Lt; / RTI >

FIG. 10 illustrates a process in which an image decoding apparatus divides a square-shaped encoding unit when the division mode mode information can not be divided into four square-shaped encoding units according to an embodiment.

FIG. 11 illustrates that the processing order among a plurality of coding units may be changed according to a division process of coding units according to an embodiment.

FIG. 12 illustrates a process of determining the depth of an encoding unit according to a change in type and size of an encoding unit when a plurality of encoding units are determined by recursively dividing an encoding unit according to an exemplary embodiment.

FIG. 13 illustrates a depth index (hereinafter referred to as PID) for coding unit classification and depth that can be determined according to the type and size of coding units according to an exemplary embodiment.

FIG. 14 shows that a plurality of coding units are determined according to a plurality of predetermined data units included in a picture according to an embodiment.

FIG. 15 illustrates a processing block serving as a reference for determining a determination order of a reference encoding unit included in a picture according to an embodiment.

16 shows a block diagram of a video decoding apparatus for obtaining a transform coefficient array of a current block based on a plurality of regions and a plurality of sub regions in which a current block is divided.

Fig. 17 shows a first embodiment for dividing a square current block having a size of N 占 N N into a plurality of zones and sub-zones, and parsing the transform coefficient information of the current block.

Fig. 18 shows a second embodiment for dividing a square current block having a size of N 占 N N into a plurality of zones and sub-zones, and parsing the transform coefficient information of the current block.

19 shows a third embodiment of dividing a square current block having a size of N 占 N N into a plurality of zones and sub-zones, and parsing the transform coefficient information of the current block.

Fig. 20 shows a fourth embodiment for dividing a rectangular current block having a size of M 占 N into a plurality of zones and sub-zones, and parsing the transform coefficient information of the current block.

Fig. 21 shows a fifth embodiment for dividing a rectangular current block having a size of M 占 N into a plurality of zones and sub-zones, and parsing the transform coefficient information of the current block.

FIG. 22 illustrates a method of dividing a current block of Mx8 size according to the dividing method of the fourth embodiment of FIG.

FIG. 23 illustrates a method of dividing a current block of Mx4 size according to the dividing method of the fourth embodiment of FIG.

FIG. 24 illustrates a method of dividing a current block of Mx2 size according to the dividing method of the fourth embodiment of FIG.

25 is a flowchart illustrating a process of entropy decoding based on a last location-based coefficient coding scheme according to an embodiment of the present invention.

FIG. 26 is a flowchart illustrating a process of entropy decoding based on an entire location-based coefficient coding scheme according to an embodiment of the present invention.

FIG. 27 is a flowchart illustrating a process of entropy decoding based on a scan area-based coefficient coding scheme according to an embodiment of the present invention.

28 is a flowchart illustrating an entropy decoding process based on an effective group-based coefficient coding scheme according to an embodiment of the present invention.

FIG. 29 is a flowchart illustrating a process of entropy decoding based on a last position and an effective group-based coefficient coding scheme according to an embodiment of the present invention.

30 is a flowchart illustrating a process of entropy decoding based on effective group and last position-based coefficient coding schemes according to an embodiment of the present invention.

31 is a view for explaining a process of entropy decoding based on a valid group and a lastRun-based coefficient coding scheme according to an embodiment of the present invention.

32 is a view for explaining a process of entropy decoding based on a first run-level-based coefficient coding scheme according to an embodiment of the present invention.

33 is a view for explaining a process of entropy decoding based on a second run-level-based coefficient coding scheme according to an embodiment of the present invention.

FIG. 34 shows a method of determining a scan area in the form of a rectangle according to an embodiment.

FIG. 35 shows a method of determining a scan area in the form of a square according to an embodiment.

Figure 36 shows the current block divided into nine sub-zones.

FIG. 37 shows a flowchart of a video decoding method for obtaining a transform coefficient array of a current block based on a plurality of zones and a plurality of sub zones in which a current block is divided.

FIG. 38 shows a block diagram of a video encoding apparatus for encoding an array of transform coefficients of a current block based on a plurality of regions and a plurality of sub regions in which the current block is divided.

FIG. 39 shows a flowchart of a video coding method for coding a transform coefficient array of a current block based on a plurality of zones and a plurality of sub zones in which the current block is divided.

Comprising the steps of: receiving a bitstream including a zone flag of a current block, a sub-zone flag, and transform coefficient information; dividing the current block into a plurality of zones; Determining which of the plurality of zones includes the last effective transform coefficient of the current block, determining a zone in which at least one effective transform coefficient of the plurality of zones may be included in a plurality of sub zones ), Determining, according to a sub-zone flag for a plurality of sub-zones of the current block, that at least one valid conversion coefficient is included for each of the plurality of sub-zones, Based on the at least one of the plurality of sub-zones, Determining a coefficient coding scheme for the current block, and acquiring a transform coefficient array of the current block by parsing the transform coefficient information of the current block according to the coefficient coding scheme, Method is provided.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the disclosed embodiments, and how to accomplish them, will become apparent with reference to the embodiments described below with reference to the accompanying drawings. It should be understood, however, that the present disclosure is not limited to the embodiments disclosed herein but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, But only to give the person who possessed the invention the full scope of the invention.

The terms used in this specification will be briefly described, and the disclosed embodiments will be described in detail.

As used herein, terms used in the present specification are taken to be those of ordinary skill in the art and are not intended to limit the scope of the present invention. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Accordingly, the terms used in this disclosure should be defined based on the meaning of the term rather than on the name of the term, and throughout the present disclosure.

The singular expressions herein include plural referents unless the context clearly dictates otherwise.

When an element is referred to as " including " an element throughout the specification, it is to be understood that the element may include other elements as well, without departing from the spirit or scope of the present invention. Also, as used herein, the term " part " refers to a hardware component such as software, FPGA or ASIC, and " part " However, " part " is not meant to be limited to software or hardware. &Quot; Part " may be configured to reside on an addressable storage medium and may be configured to play back one or more processors. Thus, by way of example, and not limitation, " part (s) " refers to components such as software components, object oriented software components, class components and task components, and processes, Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. The functions provided in the components and " parts " may be combined into a smaller number of components and " parts " or further separated into additional components and " parts ".

The " current block " means one of a coding unit, a prediction unit and a conversion unit which are currently encoded or decoded. For convenience of explanation, when it is necessary to distinguish other types of blocks such as a prediction unit, a conversion unit, a "current encoding block", a "current prediction block", and a "current conversion block" may be used. "Sub-block" means a data unit divided from "current block". And " upper block " means a data unit including " current block ".

Hereinafter, " sample " means data to be processed as data assigned to a sampling position of an image. For example, pixel values in the image of the spatial domain, and transform coefficients on the transform domain may be samples. A unit including at least one of these samples may be defined as a block.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. In order to clearly explain the present disclosure in the drawings, portions not related to the description will be omitted.

A method and apparatus for adaptively selecting a context model based on various types of encoding units in accordance with one embodiment of the present disclosure will be described below with reference to FIGS. 1A and 1B.

FIG. 1A shows a schematic block diagram of an image decoding apparatus 100 according to an embodiment.

The image decoding apparatus 100 may include a receiving unit 110 and a decoding unit 120. The receiving unit 110 and the decoding unit 120 may include at least one processor. Also, the receiving unit 110 and the decoding unit 120 may include a memory for storing instructions to be executed by at least one processor.

The receiving unit 110 may receive the bit stream. The bitstream includes information obtained by encoding an image by a video encoding apparatus 3800, which will be described later. Further, the bit stream can be transmitted from the image encoding apparatus 3800. [ The image encoding apparatus 3800 and the image decoding apparatus 100 may be connected by wire or wirelessly, and the receiving unit 110 may receive a bit stream by wire or wireless. The receiving unit 110 may receive a bit stream from a storage medium such as an optical medium, a hard disk, or the like. The decoding unit 120 may restore the image based on the information obtained from the received bitstream. The decoding unit 120 may obtain a syntax element for reconstructing an image from a bitstream. The decoding unit 120 can restore an image based on the syntax element.

The operation of the video decoding apparatus 100 will be described in detail with reference to FIG. 1B.

FIG. 1B shows a flow diagram of a video decoding method according to one embodiment.

According to one embodiment of the present disclosure, the receiving unit 110 receives a bit stream.

The video decoding apparatus 100 performs a step 150 of obtaining an empty string corresponding to the division type mode of the encoding unit from the bit stream. The video decoding apparatus 100 performs a step 160 of determining a division rule of an encoding unit. The image decoding apparatus 100 also performs a step 170 of dividing the encoding unit into a plurality of encoding units based on at least one of the bin string corresponding to the division mode mode and the division rule. The image decoding apparatus 100 may determine an allowable first range of the size of the encoding unit according to the ratio of the width and the height of the encoding unit in order to determine the segmentation rule. The video decoding apparatus 100 may determine an allowable second range of the size of the coding unit according to the division mode of coding unit in order to determine the division rule.

Hereinafter, the division of encoding units will be described in detail according to an embodiment of the present disclosure.

First, one picture may be divided into one or more slices. One slice may be a sequence of one or more Coding Tree Units (CTUs). There is a maximum coding block (CTB) as a concept to be compared with the maximum coding unit (CTU).

The maximum coding block (CTB) means an NxN block including NxN samples (N is an integer). Each color component may be divided into one or more maximum encoding blocks.

When a picture has three sample arrays (sample arrays for Y, Cr, and Cb components), the maximum encoding unit (CTU) is the maximum encoding block of the luma sample and the two maximum encoding blocks of the chroma samples corresponding thereto, Samples, and chroma samples. When the picture is a monochrome picture, the maximum encoding unit is a unit including syntax structures used for encoding the maximum encoded block and monochrome samples of the monochrome sample. When a picture is a picture encoded with a color plane separated by color components, the maximum encoding unit is a unit including syntax structures used for encoding the pictures and the samples of the picture.

One maximum coding block (CTB) may be divided into MxN coding blocks (M, N is an integer) including MxN samples.

When a picture has a sample array of Y, Cr, and Cb components, a coding unit (CU) is a coding unit that encodes two coding blocks of a luma sample coding block and corresponding chroma samples and luma samples and chroma samples Is a unit that includes syntax structures used for decoding. When the picture is a monochrome picture, the encoding unit is a unit including syntax blocks used for encoding the mono chrome samples and the encoded block of the monochrome sample. In the case where a picture is a picture encoded with a color plane separated by color components, an encoding unit is a unit including syntax structures used for encoding the pictures and the samples of the picture.

As described above, the maximum encoding block and the maximum encoding unit are concepts that are distinguished from each other, and the encoding block and the encoding unit are conceptually distinguished from each other. That is, the (maximum) coding unit means a data structure including a (maximum) coding block including a corresponding sample and a corresponding syntax structure. However, it will be understood by those skilled in the art that a (maximum) encoding unit or a (maximum) encoding block refers to a predetermined size block including a predetermined number of samples. Hence, in the following description, a maximum encoding block and a maximum encoding unit, Unless otherwise specified.

The image can be divided into a maximum coding unit (CTU). The size of the maximum encoding unit may be determined based on information obtained from the bitstream. The shape of the largest encoding unit may have a square of the same size. However, the present invention is not limited thereto.

For example, information on the maximum size of the luma encoded block from the bitstream can be obtained. For example, the maximum size of a luma encoding block indicated by information on the maximum size of a luma encoding block may be one of 16x16, 32x32, 64x64, 128x128, and 256x256.

For example, information on the maximum size and luma block size difference of a luma coding block that can be divided into two from the bitstream can be obtained. The information on the luma block size difference may indicate the size difference between the luma maximum encoding unit and the maximum luma encoding block that can be divided into two. Therefore, when the information on the maximum size of the luma coding block obtained from the bitstream and capable of being divided into two pieces is combined with information on the luma block size difference, the size of the luma maximum coding unit can be determined. Using the size of the luma maximum encoding unit, the size of the chroma maximum encoding unit can also be determined. For example, if the Y: Cb: Cr ratio is 4: 2: 0 according to the color format, the size of the chroma block may be half the size of the luma block, and the size of the chroma maximum encoding unit may be the size of the luma maximum encoding unit It can be half the size.

According to one embodiment, since the information on the maximum size of the luma coding block capable of binary division is obtained from the bitstream, the maximum size of the luma coding block capable of binary division can be variably determined. Alternatively, the maximum size of a luma coding block capable of ternary splitting can be fixed. For example, the maximum size of a luma coding block capable of ternary partitioning on an I slice is 32x32, and the maximum size of a luma coding block capable of ternary partitioning on a P slice or B slice can be 64x64.

Also, the maximum encoding unit may be hierarchically divided in units of encoding based on division mode information obtained from the bitstream. As the division type mode information, at least one of information indicating whether a quad split is performed, information indicating whether or not the division is multi-division, division direction information, and division type information may be obtained from the bitstream.

For example, information indicating whether a quad split is present may indicate whether the current encoding unit is quad-split (QUAD_SPLIT) or not quad-split.

Unless the current encoding unit is a quadrant, the information indicating whether the current encoding unit is multi-divided may indicate whether the current encoding unit is no longer divided (NO_SPLIT) or binary / ternary divided.

If the current encoding unit is binary-split or ternary-split, the division direction information indicates that the current encoding unit is divided into either the horizontal direction or the vertical direction.

If the current encoding unit is divided horizontally or vertically, the division type information indicates that the current encoding unit is divided into binary division) or ternary division.

The division mode of the current encoding unit can be determined according to the division direction information and the division type information. The division mode when the current coding unit is divided into the horizontal direction is divided into binary horizontal division (SPLIT_BT_HOR), ternary horizontal division (SPLIT_TT_HOR) when tiled in the horizontal direction, and division mode in the case of binary division in the vertical direction The binary vertical division (SPLIT_BT_VER) and the division mode in the case of ternary division in the vertical direction can be determined to be the ternary vertical division (SPLIT_BT_VER).

The image decoding apparatus 100 can obtain the split mode mode information from the bit stream in one bin string. The form of the bit stream received by the video decoding apparatus 100 may include a fixed length binary code, a unary code, a truncated unary code, and a predetermined binary code. An empty string is a binary sequence of information. The empty string may consist of at least one bit. The image decoding apparatus 100 can obtain the split mode mode information corresponding to the bin string based on the split rule. The video decoding apparatus 100 can determine whether or not to divide the encoding unit into quad, division, or division direction and division type based on one bin string.

The encoding unit may be less than or equal to the maximum encoding unit. For example, the maximum encoding unit is also one of the encoding units since it is the encoding unit having the maximum size. When the division type mode information for the maximum encoding unit indicates that the information is not divided, the encoding unit determined in the maximum encoding unit has the same size as the maximum encoding unit. If the division type mode information for the maximum encoding unit indicates division, the maximum encoding unit may be divided into encoding units. In addition, if division type mode information for an encoding unit indicates division, encoding units can be divided into smaller-sized encoding units. However, the division of the image is not limited to this, and the maximum encoding unit and the encoding unit may not be distinguished. The division of the encoding unit will be described in more detail with reference to FIG. 2 to FIG.

Also, one or more prediction blocks for prediction from the encoding unit can be determined. The prediction block may be equal to or smaller than the encoding unit. Also, one or more conversion blocks for conversion from an encoding unit may be determined. The conversion block may be equal to or smaller than the encoding unit.

The shape and size of the conversion unit and the conversion block and the prediction block may not be related to each other.

In another embodiment, prediction can be performed using an encoding unit as an encoding unit as a prediction block. Also, the conversion can be performed using the encoding unit as a conversion block as a conversion block.

The division of the encoding unit will be described in more detail with reference to FIG. 2 to FIG. The current block and the neighboring blocks of the present disclosure may represent one of a maximum encoding unit, an encoding unit, a prediction block, and a transform block. In addition, the current block or the current encoding unit is a block in which decoding or encoding is currently proceeding, or a block in which the current segmentation is proceeding. The neighboring block may be a block restored before the current block. The neighboring blocks may be spatially or temporally contiguous from the current block. The neighboring block may be located at one of the left lower side, the left side, the upper left side, the upper side, the upper right side, the right side, and the lower right side of the current block.

FIG. 2 illustrates a process in which the image decoding apparatus 100 determines at least one encoding unit by dividing a current encoding unit according to an embodiment.

The block shape may include 4Nx4N, 4Nx2N, 2Nx4N, 4NxN, or Nx4N. Where N may be a positive integer. The block type information is information indicating at least one of a ratio, or a size, of a shape, direction, width, and height of an encoding unit.

The shape of the encoding unit may include a square and a non-square. If the width and height of the encoding unit are the same (i.e., the block type of the encoding unit is 4Nx4N), the image decoding apparatus 100 can determine the block type information of the encoding unit as a square. The image decoding apparatus 100 can determine the shape of the encoding unit as a non-square.

If the width and height of the encoding unit are different (i.e., the block type of the encoding unit is 4Nx2N, 2Nx4N, 4NxN, or Nx4N), the image decoding apparatus 100 determines the block type information of the encoding unit as a non- . When the shape of the coding unit is a non-square shape, the image decoding apparatus 100 sets the width and height ratio of the block type information of the coding unit to 1: 2, 2: 1, 1: 4, 4: Or 8: 1. Further, based on the length of the width of the coding unit and the length of the height, the video decoding apparatus 100 can determine whether the coding unit is the horizontal direction or the vertical direction. Further, the image decoding apparatus 100 can determine the size of the encoding unit based on at least one of the width of the encoding unit, the length of the height, and the width.

According to an exemplary embodiment, the image decoding apparatus 100 may determine the type of the encoding unit using the block type information, and may determine the type of the encoding unit to be divided using the division type mode information. That is, the division method of the coding unit indicated by the division type mode information can be determined according to which block type the block type information used by the video decoding apparatus 100 represents.

The image decoding apparatus 100 can obtain the split mode information from the bit stream. However, the present invention is not limited thereto, and the image decoding apparatus 100 and the image encoding apparatus 3800 can determine the promised divided mode information based on the block type information. The video decoding apparatus 100 can determine the promised divided mode mode information for the maximum encoding unit or the minimum encoding unit. For example, the image decoding apparatus 100 may determine the division type mode information as a quad split with respect to the maximum encoding unit. Also, the video decoding apparatus 100 can determine the division type mode information to be " not divided " for the minimum encoding unit. Specifically, the image decoding apparatus 100 can determine the size of the maximum encoding unit to be 256x256. The video decoding apparatus 100 can determine the promised division mode information in advance by quad division. Quad partitioning is a split mode mode that bisects both the width and the height of the encoding unit. The image decoding apparatus 100 can obtain a 128x128 encoding unit from the 256x256 maximum encoding unit based on the division type mode information. Also, the image decoding apparatus 100 can determine the size of the minimum encoding unit to be 4x4. The image decoding apparatus 100 can obtain the division type mode information indicating " not divided " for the minimum encoding unit.

According to one embodiment, the image decoding apparatus 100 may use block type information indicating that the current encoding unit is a square type. For example, the image decoding apparatus 100 can determine whether to divide a square encoding unit according to division type mode information, vertically or horizontally, four encoding units, or the like. 2, if the block type information of the current encoding unit 200 indicates a square shape, the decoding unit 120 decodes the same size as the current encoding unit 200 according to the split mode mode information indicating that the current block is not divided (210b), 210c (210d), etc.) based on the division type mode information indicating the predetermined division method.

Referring to FIG. 2, the image decoding apparatus 100 includes two encoding units 210b, which are obtained by dividing the current encoding unit 200 in the vertical direction, based on the division mode information indicating that the image is divided vertically according to an embodiment You can decide. The image decoding apparatus 100 may determine two encoding units 210c that are obtained by dividing the current encoding unit 200 in the horizontal direction based on the split mode mode information indicating that the image is divided in the horizontal direction. The image decoding apparatus 100 may determine the four coding units 210d obtained by dividing the current coding unit 200 in the vertical direction and the horizontal direction based on the division type mode information indicating that the image is divided in the vertical direction and the horizontal direction. However, a division type in which a square coding unit can be divided should not be limited to the above-described type, and various types of division mode information can be included. The predetermined divisional form in which the square encoding unit is divided will be described in detail by way of various embodiments below.

FIG. 3 illustrates a process in which the image decoding apparatus 100 determines at least one encoding unit by dividing a non-square encoding unit according to an embodiment.

According to an embodiment, the image decoding apparatus 100 may use block type information indicating that the current encoding unit is a non-square format. The image decoding apparatus 100 may determine whether to divide the non-square current encoding unit according to the division mode mode information or not in a predetermined method. 3, when the block type information of the current encoding unit 300 or 350 indicates a non-square shape, the image decoding apparatus 100 determines whether the current encoding unit 320b, 330a, 330b, 330c, and 370a (320a, 320b, 330a, 330b, 330c, and 350d) that are divided based on division mode mode information indicating a predetermined division method, , 370b, 380a, 380b, and 380c. The predetermined division method in which the non-square coding unit is divided will be described in detail through various embodiments.

According to an exemplary embodiment, the image decoding apparatus 100 may determine the type in which the encoding unit is divided using the division type mode information. In this case, the division type mode information may include at least one of the encoding units Can be expressed. 3, when the division type mode information indicates that the current encoding unit 300 or 350 is divided into two encoding units, the image decoding apparatus 100 determines whether the current encoding unit 300 or 350 is divided based on the division type mode information, 350) to determine two encoding units 320a, 320b, or 370a, 370b included in the current encoding unit.

When the video decoding apparatus 100 divides the current coding unit 300 or 350 in the form of non-square based on the division type mode information, the video decoding apparatus 100 divides the current coding unit 300 or 350 into non- The current encoding unit can be divided in consideration of the long side position of the encoding unit 300 or 350. [ For example, the image decoding apparatus 100 divides the current encoding unit 300 or 350 in the direction of dividing the long side of the current encoding unit 300 or 350 in consideration of the type of the current encoding unit 300 or 350 So that a plurality of encoding units can be determined.

According to one embodiment, when the division type mode information indicates that an encoding unit is divided into an odd number of blocks (ternary division), the video decoding apparatus 100 performs an odd number of encodings included in the current encoding unit 300 or 350 The unit can be determined. For example, when the division type mode information indicates that the current encoding unit 300 or 350 is divided into three encoding units, the video decoding apparatus 100 converts the current encoding unit 300 or 350 into three encoding units 330a, 330b, 330c, 380a, 380b, and 380c.

According to one embodiment, the ratio of the width and height of the current encoding unit 300 or 350 may be 4: 1 or 1: 4. If the ratio of width to height is 4: 1, the length of the width is longer than the length of the height, so the block type information may be horizontal. If the ratio of width to height is 1: 4, the block type information may be vertical because the length of the width is shorter than the length of the height. The image decoding apparatus 100 may determine to divide the current encoding unit into odd number blocks based on the division type mode information. Also, the image decoding apparatus 100 can determine the dividing direction of the current encoding unit 300 or 350 based on the block type information of the current encoding unit 300 or 350. [ For example, if the current encoding unit 300 is the vertical direction, the image decoding apparatus 100 may determine the encoding units 330a, 330b, and 330c by dividing the current encoding unit 300 in the horizontal direction. If the current encoding unit 350 is the horizontal direction, the image decoding apparatus 100 can determine the encoding units 380a, 380b, and 380c by dividing the current encoding unit 350 in the vertical direction.

According to an exemplary embodiment, the image decoding apparatus 100 may determine an odd number of encoding units included in the current encoding unit 300 or 350, and the sizes of the determined encoding units may not be the same. For example, the size of the predetermined encoding unit 330b or 380b among the determined odd number of encoding units 330a, 330b, 330c, 380a, 380b, and 380c is different from the size of the other encoding units 330a, 330c, 380a, and 380c . That is, an encoding unit that can be determined by dividing the current encoding unit 300 or 350 may have a plurality of types of sizes, and in some cases, an odd number of encoding units 330a, 330b, 330c, 380a, 380b, May have different sizes.

According to one embodiment, when the division type mode information indicates that an encoding unit is divided into an odd number of blocks, the image decoding apparatus 100 can determine an odd number of encoding units included in the current encoding unit 300 or 350, Furthermore, the image decoding apparatus 100 may set a predetermined restriction on at least one of the odd number of encoding units generated by division. Referring to FIG. 3, the image decoding apparatus 100 includes a coding unit 330a, 330b, 330c, 380a, 380b, and 380c generated by dividing a current coding unit 300 or 350, (330b, 380b) may be different from the other encoding units (330a, 330c, 380a, 380c). For example, in the video decoding apparatus 100, unlike the other encoding units 330a, 330c, 380a, and 380c, the encoding units 330b and 380b positioned at the center are restricted so as not to be further divided, It can be limited to be divided.

FIG. 4 illustrates a process in which the image decoding apparatus 100 divides an encoding unit based on at least one of divided mode information according to an embodiment.

According to an exemplary embodiment, the image decoding apparatus 100 may determine to divide or not divide the first encoding unit 400 of a rectangular shape into encoding units based on at least one of the division type mode information. According to one embodiment, when the division type mode information indicates that the first encoding unit 400 is divided in the horizontal direction, the image decoding apparatus 100 divides the first encoding unit 400 in the horizontal direction, The unit 410 can be determined. The first encoding unit, the second encoding unit, and the third encoding unit used according to an embodiment are terms used to understand the relation before and after the division between encoding units. For example, if the first encoding unit is divided, the second encoding unit can be determined, and if the second encoding unit is divided, the third encoding unit can be determined. Hereinafter, the relationship between the first coding unit, the second coding unit and the third coding unit used can be understood to be in accordance with the above-mentioned characteristic.

According to an exemplary embodiment, the image decoding apparatus 100 may determine that the determined second encoding unit 410 is divided or not divided into encoding units based on the division mode information. Referring to FIG. 4, the image decoding apparatus 100 divides a second encoding unit 410 of a non-square shape determined by dividing a first encoding unit 400 based on division mode information into at least one third encoding 420a, 420b, 420c, 420d, etc., or the second encoding unit 410 may not be divided. The image decoding apparatus 100 can obtain the division type mode information and the image decoding apparatus 100 divides the first encoding unit 400 based on the obtained division type mode information to generate a plurality of second encoding The second encoding unit 410 may be divided according to the manner in which the first encoding unit 400 is divided based on the division mode mode information. According to one embodiment, when the first encoding unit 400 is divided into the second encoding units 410 based on the division type mode information for the first encoding unit 400, the second encoding units 410 (E.g., 420a, 420b, 420c, 420d, etc.) on the basis of the division type mode information for the second encoding unit 410. [ That is, the encoding unit may be recursively divided based on the division mode information associated with each encoding unit. Therefore, a square encoding unit may be determined in a non-square encoding unit, and a non-square encoding unit may be determined by dividing the square encoding unit recursively.

Referring to FIG. 4, among the odd third encoding units 420b, 420c and 420d in which the non-square second encoding unit 410 is divided and determined, predetermined encoding units (for example, An encoding unit or a square-shaped encoding unit) can be recursively divided. In an exemplary embodiment, the third encoding unit 420b, which is one of the odd-numbered third encoding units 420b, 420c, and 420d, may be divided in the horizontal direction and divided into a plurality of fourth encoding units. The non-square fourth encoding unit 430b or 430d, which is one of the plurality of fourth encoding units 430a, 430b, 430c, and 430d, may be divided into a plurality of encoding units. For example, the non-square-shaped fourth encoding unit 430b or 430d may be divided again into odd-numbered encoding units. A method which can be used for recursive division of an encoding unit will be described later in various embodiments.

According to an embodiment, the image decoding apparatus 100 may divide each of the third encoding units 420a, 420b, 420c, and 420d into encoding units based on the division type mode information. Also, the image decoding apparatus 100 may determine that the second encoding unit 410 is not divided based on the division type mode information. The image decoding apparatus 100 may divide the second encoding unit 410 in the non-square form into an odd number of third encoding units 420b, 420c and 420d according to an embodiment. The image decoding apparatus 100 may set a predetermined restriction on a predetermined third encoding unit among the odd number of third encoding units 420b, 420c, and 420d. For example, the image decoding apparatus 100 may restrict the encoding unit 420c located in the middle among the odd-numbered third encoding units 420b, 420c, and 420d to no longer be divided or be divided into a set number of times .

Referring to FIG. 4, the image decoding apparatus 100 includes an encoding unit (not shown) positioned in the middle of an odd number of third encoding units 420b, 420c, and 420d included in a second encoding unit 410 of a non- 420c are not further divided or are limited to being divided into a predetermined division form (for example, divided into four coding units or divided into a form corresponding to a form in which the second coding units 410 are divided) (For example, dividing only n times, n > 0). The above restriction on the encoding unit 420c positioned at the center is merely an example and should not be construed to be limited to the above embodiments and the encoding unit 420c positioned at the center is not limited to the other encoding units 420b and 420d Quot;), < / RTI > which can be decoded differently.

According to an exemplary embodiment, the image decoding apparatus 100 may acquire division mode information used for dividing a current encoding unit at a predetermined position in a current encoding unit.

FIG. 5 illustrates a method by which the image decoding apparatus 100 determines an encoding unit of a predetermined position among odd number of encoding units according to an embodiment.

Referring to FIG. 5, the division type mode information of the current encoding units 500 and 550 is a sample of a predetermined position among a plurality of samples included in the current encoding units 500 and 550 (for example, 540, 590). However, the predetermined position in the current coding unit 500 in which at least one of the division mode information can be obtained should not be limited to the middle position shown in FIG. 5, and the predetermined position should be included in the current coding unit 500 (E.g., top, bottom, left, right, top left, bottom left, top right or bottom right, etc.) The image decoding apparatus 100 may determine division mode mode information obtained from a predetermined position and divide the current encoding unit into the encoding units of various types and sizes.

According to an exemplary embodiment, when the current encoding unit is divided into a predetermined number of encoding units, the image decoding apparatus 100 may select one of the encoding units. The method for selecting one of the plurality of encoding units may be various, and description of these methods will be described later in various embodiments.

According to an exemplary embodiment, the image decoding apparatus 100 may divide the current encoding unit into a plurality of encoding units and determine a predetermined encoding unit.

According to an exemplary embodiment, the image decoding apparatus 100 may use information indicating the positions of odd-numbered encoding units in order to determine an encoding unit located in the middle among odd-numbered encoding units. 5, the image decoding apparatus 100 divides the current encoding unit 500 or the current encoding unit 550 into odd number of encoding units 520a, 520b, 520c or odd number of encoding units 560a, 560b, and 560c. The image decoding apparatus 100 may use the information on the positions of the odd number of coding units 520a, 520b and 520c or the odd number of coding units 560a, 560b and 560c to generate the middle coding unit 520b or the middle coding unit 520b, (560b). For example, the image decoding apparatus 100 determines the positions of the encoding units 520a, 520b, and 520c based on information indicating the positions of predetermined samples included in the encoding units 520a, 520b, and 520c, The encoding unit 520b located in the encoding unit 520 can be determined. Specifically, the video decoding apparatus 100 encodes the encoding units 520a, 520b, and 520c based on information indicating the positions of the upper left samples 530a, 530b, and 530c of the encoding units 520a, The coding unit 520b located in the center can be determined.

Information indicating the positions of the upper left samples 530a, 530b, and 530c included in the coding units 520a, 520b, and 520c according to one embodiment is stored in the pictures of the coding units 520a, 520b, and 520c Or information about the position or coordinates of the object. Information indicating the positions of the upper left samples 530a, 530b, and 530c included in the coding units 520a, 520b, and 520c according to one embodiment is stored in the coding units 520a 520b, and 520c, and the width or height may correspond to information indicating a difference between coordinates in the pictures of the encoding units 520a, 520b, and 520c. That is, the image decoding apparatus 100 directly uses the information on the position or the coordinates in the pictures of the coding units 520a, 520b, and 520c or the information on the width or height of the coding unit corresponding to the difference value between the coordinates The encoding unit 520b located in the center can be determined.

The information indicating the position of the upper left sample 530a of the upper coding unit 520a may indicate the coordinates of (xa, ya) and the upper left sample 530b of the middle coding unit 520b May indicate the coordinates of (xb, yb), and information indicating the position of the upper left sample 530c of the lower coding unit 520c may indicate (xc, yc) coordinates. The video decoding apparatus 100 can determine the center encoding unit 520b using the coordinates of the upper left samples 530a, 530b, and 530c included in the encoding units 520a, 520b, and 520c. For example, when the coordinates of the upper left samples 530a, 530b, and 530c are arranged in ascending or descending order, the coding unit 520b including (xb, yb) coordinates of the sample 530b positioned at the center, 520b, and 520c determined by dividing the current encoding unit 500 as the encoding units located in the middle of the encoding units 520a, 520b, and 520c. However, the coordinates indicating the positions of the upper left samples 530a, 530b, and 530c may indicate the coordinates indicating the absolute position in the picture, and the position of the upper left sample unit 530a of the upper coding unit 520a may be (Dxb, dyb), which is information indicating the relative position of the upper left sample 530b of the middle coding unit 520b, and the relative position of the upper left sample 530c of the lower coding unit 520c Information dyn (dxc, dyc) coordinates may also be used. Also, the method of determining the coding unit at a predetermined position by using the coordinates of the sample as information indicating the position of the sample included in the coding unit should not be limited to the above-described method, and various arithmetic Should be interpreted as a method.

According to an embodiment, the image decoding apparatus 100 may divide the current encoding unit 500 into a plurality of encoding units 520a, 520b, and 520c, and may encode a predetermined one of the encoding units 520a, 520b, and 520c The encoding unit can be selected according to the criterion. For example, the image decoding apparatus 100 can select an encoding unit 520b having a different size from among the encoding units 520a, 520b, and 520c.

According to an embodiment, the image decoding apparatus 100 may include (xa, ya) coordinates which are information indicating the position of a sample 530a at the upper left of the upper encoding unit 520a, a sample at the upper left of the middle encoding unit 520b (Xc, yc), which is information indicating the position of the lower-stage coding unit 530b and the position of the upper-left sample 530c of the lower-stage coding unit 520c, , 520b, and 520c, respectively. The image decoding apparatus 100 encodes the encoded units 520a, 520b, and 520c using coordinates (xa, ya), (xb, yb), (xc, yc) indicating the positions of the encoding units 520a, , And 520c, respectively. According to an embodiment, the video decoding apparatus 100 may determine the width of the upper encoding unit 520a as the width of the current encoding unit 500. [ The image decoding apparatus 100 can determine the height of the upper encoding unit 520a as yb-ya. The image decoding apparatus 100 may determine the width of the middle encoding unit 520b as the width of the current encoding unit 500 according to an embodiment. The image decoding apparatus 100 can determine the height of the center encoding unit 520b as yc-yb. The image decoding apparatus 100 may determine the width or height of the lower encoding unit using the width or height of the current encoding unit and the width and height of the upper encoding unit 520a and the middle encoding unit 520b . The image decoding apparatus 100 may determine an encoding unit having a different size from the other encoding units based on the widths and heights of the determined encoding units 520a, 520b and 520c. Referring to FIG. 5, the image decoding apparatus 100 may determine a coding unit 520b as a coding unit at a predetermined position while having a size different from that of the upper coding unit 520a and the lower coding unit 520c. However, the process of determining the encoding unit having a size different from that of the other encoding units by the video decoding apparatus 100 may be the same as that of the first embodiment in which the encoding unit of a predetermined position is determined using the size of the encoding unit determined based on the sample coordinates , Various processes may be used for determining the encoding unit at a predetermined position by comparing the sizes of the encoding units determined according to predetermined sample coordinates.

The image decoding apparatus 100 calculates the position (xd, yd) indicating the position of the upper left sample 570a of the left encoding unit 560a and the position (xd, yd) of the upper left sample 570b of the middle encoding unit 560b 560b and 560c using the (xf, yf) coordinates which are information indicating the (xe, ye) coordinates which are the information indicating the position of the right upper coding unit 560c and the position of the upper left sample 570c of the right coding unit 560c, Each width or height can be determined. The image decoding apparatus 100 encodes the encoded data in the encoding units 560a and 560b using the coordinates (xd, yd), (xe, ye), (xf, yf) indicating the positions of the encoding units 560a, 560b and 560c , 560c can be determined.

According to one embodiment, the image decoding apparatus 100 can determine the width of the left encoding unit 560a as xe-xd. The image decoding apparatus 100 can determine the height of the left encoding unit 560a as the height of the current encoding unit 550. [ According to an embodiment, the image decoding apparatus 100 can determine the width of the middle encoding unit 560b as xf-xe. The image decoding apparatus 100 can determine the height of the middle encoding unit 560b as the height of the current encoding unit 500. [ The width or height of the right encoding unit 560c may be determined by the width or height of the current encoding unit 550 and the width and height of the left encoding unit 560a and the middle encoding unit 560b . ≪ / RTI > The image decoding apparatus 100 may determine an encoding unit having a different size from the other encoding units based on the widths and heights of the determined encoding units 560a, 560b, and 560c. Referring to FIG. 5, the image decoding apparatus 100 may determine a coding unit 560b as a coding unit at a predetermined position while having a size different from that of the left coding unit 560a and the right coding unit 560c. However, the process of determining the encoding unit having a size different from that of the other encoding units by the video decoding apparatus 100 may be the same as that of the first embodiment in which the encoding unit of a predetermined position is determined using the size of the encoding unit determined based on the sample coordinates , Various processes may be used for determining the encoding unit at a predetermined position by comparing the sizes of the encoding units determined according to predetermined sample coordinates.

However, the position of the sample to be considered for determining the position of the coding unit should not be interpreted as being limited to the left upper end, and information about the position of any sample included in the coding unit can be interpreted as being available.

According to one embodiment, the image decoding apparatus 100 can select a coding unit at a predetermined position among the odd number of coding units determined by dividing the current coding unit considering the type of the current coding unit. For example, if the current coding unit is a non-square shape having a width greater than the height, the image decoding apparatus 100 can determine a coding unit at a predetermined position along the horizontal direction. That is, the image decoding apparatus 100 may determine one of the encoding units which are located in the horizontal direction and limit the encoding unit. If the current coding unit is a non-square shape having a height greater than the width, the image decoding apparatus 100 can determine a coding unit at a predetermined position in the vertical direction. That is, the image decoding apparatus 100 may determine one of the encoding units having different positions in the vertical direction and set a restriction on the encoding unit.

According to an exemplary embodiment, the image decoding apparatus 100 may use information indicating positions of even-numbered encoding units in order to determine an encoding unit at a predetermined position among the even-numbered encoding units. The image decoding apparatus 100 can determine an even number of encoding units by dividing the current encoding unit (binary division) and determine a predetermined encoding unit using information on the positions of the even number of encoding units. A concrete procedure for this is omitted because it may be a process corresponding to a process of determining a coding unit of a predetermined position (for example, the middle position) among the above-mentioned odd number of coding units.

According to one embodiment, when a non-square current encoding unit is divided into a plurality of encoding units, in order to determine an encoding unit at a predetermined position among a plurality of encoding units, Can be used. For example, in order to determine a coding unit located in the middle of coding units in which the current coding unit is divided into a plurality of coding units, the video decoding apparatus 100 selects at least one of the divided mode information stored in the samples included in the middle coding unit One can be used.

Referring to FIG. 5, the image decoding apparatus 100 may divide the current encoding unit 500 into a plurality of encoding units 520a, 520b, and 520c based on the division type mode information, 520a, 520b, and 520c, among the encoding units 520a, 520b, 520c, and 520c. Furthermore, the image decoding apparatus 100 can determine the coding unit 520b positioned at the center in consideration of the position at which the split mode information is obtained. That is, the division type mode information of the current encoding unit 500 can be obtained in the sample 540 located in the center of the current encoding unit 500, and the current encoding unit 500 can be obtained based on the division mode information When the encoding unit 520 is divided into a plurality of encoding units 520a, 520b, and 520c, the encoding unit 520b including the sample 540 may be determined as an encoding unit located at the center. However, the information used for determining the coding unit located in the middle should not be limited to the division type mode information, and various kinds of information can be used in the process of determining the coding unit located in the middle.

According to an embodiment, predetermined information for identifying a coding unit at a predetermined position may be obtained from a predetermined sample included in a coding unit to be determined. Referring to FIG. 5, the image decoding apparatus 100 includes a plurality of encoding units 520a, 520b, and 520c that are determined by dividing the current encoding unit 500, Obtained from a sample at a predetermined position in the current encoding unit 500 (for example, a sample located in the middle of the current encoding unit 500) in order to determine an encoding mode unit Can be used. That is, the image decoding apparatus 100 can determine a sample of the predetermined position in consideration of the block form of the current encoding unit 500, and the image decoding apparatus 100 can decode a plurality of It is possible to determine a coding unit 520b including a sample from which predetermined information (for example, divided mode information) can be obtained, among the number of coding units 520a, 520b and 520c . Referring to FIG. 5, the image decoding apparatus 100 may determine a sample 540 located in the center of the current encoding unit 500 as a sample from which predetermined information can be obtained, The encoding unit 520 may limit the encoding unit 520b including the sample 540 to a predetermined limit in the decoding process. However, the position of the sample from which the predetermined information can be obtained should not be construed to be limited to the above-mentioned position, but may be interpreted as samples at arbitrary positions included in the encoding unit 520b to be determined for limiting.

The position of a sample from which predetermined information can be obtained may be determined according to the type of the current encoding unit 500 according to an embodiment. According to one embodiment, the block type information can determine whether the current encoding unit is a square or a non-square, and determine the position of a sample from which predetermined information can be obtained according to the shape. For example, the video decoding apparatus 100 may use at least one of the information on the width of the current coding unit and the information on the height to position at least one of the width and the height of the current coding unit in half The sample can be determined as a sample from which predetermined information can be obtained. For example, when the block type information related to the current encoding unit is a non-square type, the image decoding apparatus 100 selects one of the samples adjacent to the boundary dividing the longer side of the current encoding unit into halves by a predetermined Can be determined as a sample from which the information of < / RTI >

According to an exemplary embodiment, when the current encoding unit is divided into a plurality of encoding units, the image decoding apparatus 100 may use the division mode information to determine a predetermined unit of the plurality of encoding units. According to an embodiment, the image decoding apparatus 100 may acquire division type mode information from a sample at a predetermined position included in an encoding unit, and the image decoding apparatus 100 may include a plurality of encoding units The units may be divided using the division mode information obtained from the sample at a predetermined position included in each of the plurality of encoding units. That is, the coding unit can be recursively divided using the division type mode information obtained in the sample at the predetermined position contained in each of the coding units. Since the recursive division process of the encoding unit has been described with reference to FIG. 5, a detailed description thereof will be omitted.

According to an embodiment, the image decoding apparatus 100 can determine at least one encoding unit by dividing the current encoding unit, and the order in which the at least one encoding unit is decoded is determined as a predetermined block (for example, ). ≪ / RTI >

FIG. 6 illustrates a sequence in which a plurality of encoding units are processed when the image decoding apparatus 100 determines a plurality of encoding units by dividing the current encoding unit according to an exemplary embodiment.

The image decoding apparatus 100 may determine the second encoding units 610a and 610b by dividing the first encoding unit 600 in the vertical direction according to the split mode information, The second encoding units 650a, 650b, 650c, and 650d may be determined by dividing the first encoding units 600 in the vertical direction and the horizontal direction by determining the second encoding units 630a and 630b in the horizontal direction have.

Referring to FIG. 6, the image decoding apparatus 100 may determine the order in which the second encoding units 610a and 610b determined by dividing the first encoding unit 600 in the vertical direction are processed in the horizontal direction 610c . The image decoding apparatus 100 may determine the processing order of the second encoding units 630a and 630b determined by dividing the first encoding unit 600 in the horizontal direction as the vertical direction 630c. The image decoding apparatus 100 processes the encoding units located in one row of the second encoding units 650a, 650b, 650c, and 650d determined by dividing the first encoding unit 600 in the vertical direction and the horizontal direction (For example, a raster scan order or a z scan order 650e) in which the encoding units located in the next row are processed.

According to an embodiment, the image decoding apparatus 100 may recursively divide encoding units. 6, the image decoding apparatus 100 may determine a plurality of encoding units 610a, 610b, 630a, 630b, 650a, 650b, 650c, and 650d by dividing the first encoding unit 600, The determined plurality of encoding units 610a, 610b, 630a, 630b, 650a, 650b, 650c and 650d may be recursively divided. The method of dividing the plurality of encoding units 610a, 610b, 630a, 630b, 650a, 650b, 650c, and 650d may be a method corresponding to the method of dividing the first encoding unit 600. [ Accordingly, the plurality of encoding units 610a, 610b, 630a, 630b, 650a, 650b, 650c, and 650d may be independently divided into a plurality of encoding units. Referring to FIG. 6, the image decoding apparatus 100 may determine the second encoding units 610a and 610b by dividing the first encoding unit 600 in the vertical direction, and may further determine the second encoding units 610a and 610b Can be determined not to divide or separate independently.

The image decoding apparatus 100 may divide the second encoding unit 610a on the left side in the horizontal direction into the third encoding units 620a and 620b and the second encoding units 610b ) May not be divided.

According to an embodiment, the processing order of the encoding units may be determined based on the division process of the encoding units. In other words, the processing order of the divided coding units can be determined based on the processing order of the coding units immediately before being divided. The image decoding apparatus 100 may determine the order in which the third encoding units 620a and 620b determined by dividing the left second encoding unit 610a are processed independently of the second encoding unit 610b on the right side. The third encoding units 620a and 620b may be processed in the vertical direction 620c since the second encoding units 610a on the left side are divided in the horizontal direction and the third encoding units 620a and 620b are determined. Since the order in which the left second encoding unit 610a and the right second encoding unit 610b are processed corresponds to the horizontal direction 610c, the third encoding unit included in the left second encoding unit 610a The right encoding unit 610b can be processed after the blocks 620a and 620b are processed in the vertical direction 620c. The above description is intended to explain the process sequence in which encoding units are determined according to the encoding units before division. Therefore, it should not be construed to be limited to the above-described embodiments, It should be construed as being used in various ways that can be handled independently in sequence.

7 illustrates a process of determining that the current encoding unit is divided into odd number of encoding units when the image decoding apparatus 100 can not process the encoding units in a predetermined order according to an embodiment.

According to an embodiment, the image decoding apparatus 100 may determine that the current encoding unit is divided into odd number of encoding units based on the obtained division mode mode information. Referring to FIG. 7, the first encoding unit 700 of a square shape can be divided into second non-square encoding units 710a and 710b, and the second encoding units 710a and 710b can be independently 3 encoding units 720a, 720b, 720c, 720d, and 720e. According to an embodiment, the image decoding apparatus 100 may determine a plurality of third encoding units 720a and 720b by dividing the left encoding unit 710a among the second encoding units in the horizontal direction, and the right encoding unit 710b May be divided into an odd number of third encoding units 720c, 720d, and 720e.

According to an embodiment, the image decoding apparatus 100 determines whether or not the third encoding units 720a, 720b, 720c, 720d, and 720e can be processed in a predetermined order and determines whether there are odd-numbered encoding units You can decide. Referring to FIG. 7, the image decoding apparatus 100 may divide the first encoding unit 700 recursively to determine the third encoding units 720a, 720b, 720c, 720d, and 720e. The image decoding apparatus 100 may further include a first encoding unit 700, a second encoding unit 710a and 710b or a third encoding unit 720a, 720b, 720c, 720d, 720e ) Is divided into odd number of coding units among the divided types. For example, an encoding unit located on the right of the second encoding units 710a and 710b may be divided into odd third encoding units 720c, 720d, and 720e. The order in which the plurality of coding units included in the first coding unit 700 are processed may be a predetermined order (for example, a z-scan order 730) 100 can determine whether the third encoding units 720c, 720d, and 720e determined by dividing the right second encoding unit 710b into odd numbers satisfy the condition that the third encoding units 720c, 720d, and 720e can be processed according to the predetermined order.

According to an embodiment, the image decoding apparatus 100 satisfies a condition that the third encoding units 720a, 720b, 720c, 720d, and 720e included in the first encoding unit 700 can be processed in a predetermined order And it is determined whether or not at least one of the widths and heights of the second encoding units 710a and 710b is divided in half according to the boundaries of the third encoding units 720a, 720b, 720c, 720d, and 720e, . For example, the third encoding units 720a and 720b determined by dividing the height of the left second encoding unit 710a in the non-square shape by half are satisfying the condition, but the right second encoding unit 710b is set to 3 Since the boundaries of the third encoding units 720c, 720d, and 720e, which are determined by dividing the first encoding units 720c, 720d, and 720e, can not divide the width or the height of the second right encoding unit 710b by half, 720e may be determined as not satisfying the condition and the image decoding apparatus 100 determines that the scanning order is disconnection in the case of such unsatisfactory condition and the right second encoding unit 710b is determined based on the determination result It can be determined to be divided into odd number of encoding units. According to an embodiment, the image decoding apparatus 100 may limit a coding unit of a predetermined position among the divided coding units when the coding unit is divided into odd number of coding units. Since the embodiment has been described above, a detailed description thereof will be omitted.

FIG. 8 illustrates a process in which the image decoding apparatus 100 determines at least one encoding unit by dividing a first encoding unit 800 according to an embodiment.

According to an exemplary embodiment, the image decoding apparatus 100 may divide the first encoding unit 800 based on the division type mode information acquired through the receiver 160. The first encoding unit 800 in the form of a square may be divided into four encoding units having a square form, or may be divided into a plurality of encoding units of a non-square form. For example, referring to FIG. 8, when the first encoding unit 800 is square and the split mode mode information is divided into non-square encoding units, the image decoding apparatus 100 transmits the first encoding unit 800 And may be divided into a plurality of non-square encoding units. Specifically, when the division type mode information indicates that an odd number of encoding units are determined by dividing the first encoding unit 800 in the horizontal direction or the vertical direction, the video decoding apparatus 100 determines whether the first encoding unit 800 can be divided into the second encoding units 810a, 810b, and 810c divided in the vertical direction as the odd number of encoding units or the second encoding units 820a, 820b, and 820c determined in the horizontal direction.

According to an exemplary embodiment, the image decoding apparatus 100 may be configured such that the second encoding units 810a, 810b, 810c, 820a, 820b, and 820c included in the first encoding unit 800 are processed in a predetermined order And the condition is that at least one of the width and height of the first encoding unit 800 is divided in half according to the boundaries of the second encoding units 810a, 810b, 810c, 820a, 820b, and 820c . 8, the boundaries of the second encoding units 810a, 810b and 810c, which are determined by dividing the first encoding unit 800 in the vertical direction into a square shape, are divided in half by the width of the first encoding unit 800 The first encoding unit 800 can be determined as not satisfying a condition that can be processed in a predetermined order. Also, since the boundaries of the second encoding units 820a, 820b, and 820c determined by dividing the first encoding unit 800 in the horizontal direction into the horizontal direction can not divide the width of the first encoding unit 800 in half, 1 encoding unit 800 may be determined as not satisfying a condition that can be processed in a predetermined order. The image decoding apparatus 100 may determine that the scan order is disconnection in the case of such unsatisfactory condition and determine that the first encoding unit 800 is divided into odd number of encoding units based on the determination result. According to an embodiment, the image decoding apparatus 100 may limit a coding unit of a predetermined position among the divided coding units when the coding unit is divided into odd number of coding units. Since the embodiment has been described above, a detailed description thereof will be omitted.

According to an embodiment, the image decoding apparatus 100 may determine the encoding units of various types by dividing the first encoding unit.

8, the image decoding apparatus 100 may divide a first encoding unit 800 in a square form and a first encoding unit 830 or 850 in a non-square form into various types of encoding units .

9 is a diagram illustrating an example of a case where the second encoding unit is divided if the second encoding unit of the non-square type determined by dividing the first encoding unit 900 by the image decoding apparatus 100 satisfies a predetermined condition Lt; RTI ID = 0.0 > limited. ≪ / RTI >

According to an embodiment, the image decoding apparatus 100 may convert the first encoding unit 900 in the square form into the second encoding units 910a, 910b in the non-square format based on the division mode information obtained through the receiver 160, 910b, 920a, and 920b. The second encoding units 910a, 910b, 920a, and 920b may be independently divided. Accordingly, the image decoding apparatus 100 can determine whether to divide or not divide into a plurality of coding units based on the division type mode information associated with each of the second coding units 910a, 910b, 920a, and 920b. According to an embodiment, the image decoding apparatus 100 divides the non-square left second encoding unit 910a determined by dividing the first encoding unit 900 in the vertical direction into a horizontal direction, 912a, and 912b. However, when the left second encoding unit 910a is divided in the horizontal direction, the right second encoding unit 910b is arranged in the horizontal direction in the same direction as the left second encoding unit 910a, As shown in Fig. If the right second encoding unit 910b is divided in the same direction and the third encoding units 914a and 914b are determined, the left second encoding unit 910a and the right second encoding unit 910b are arranged in the horizontal direction The third encoding units 912a, 912b, 914a, and 914b can be determined by being independently divided. However, this is the same result that the image decoding apparatus 100 divides the first encoding unit 900 into four square-shaped second encoding units 930a, 930b, 930c, and 930d based on the split mode information, It may be inefficient in terms of image decoding.

According to one embodiment, the image decoding apparatus 100 divides the second encoding unit 920a or 920b in the non-square form determined by dividing the first encoding unit 330 in the horizontal direction into the vertical direction, (922a, 922b, 924a, 924b). However, if one of the second coding units (for example, the upper second coding unit 920a) is divided in the vertical direction, the video decoding apparatus 100 may generate a second coding unit (for example, Coding unit 920b) can be restricted so that the upper second encoding unit 920a can not be divided vertically in the same direction as the divided direction.

FIG. 10 illustrates a process in which the image decoding apparatus 100 divides a square-shaped encoding unit when the split mode information can not be divided into four square-shaped encoding units according to an embodiment.

The image decoding apparatus 100 may determine the second encoding units 1010a, 1010b, 1020a, and 1020b by dividing the first encoding unit 1000 based on the division type mode information. The division type mode information may include information on various types in which an encoding unit can be divided, but information on various types may not include information for division into four square units of encoding units. According to the division type mode information, the image decoding apparatus 100 can not divide the first encoding unit 1000 in the square form into the second encoding units 1030a, 1030b, 1030c, and 1030d in the form of four squares. The image decoding apparatus 100 can determine the second encoding units 1010a, 1010b, 1020a, and 1020b in the non-square form based on the split mode information.

According to an exemplary embodiment, the image decoding apparatus 100 may independently divide the non-square second encoding units 1010a, 1010b, 1020a, and 1020b, respectively. Each of the second encoding units 1010a, 1010b, 1020a, 1020b, and the like may be divided in a predetermined order through a recursive method, which is a method of dividing the first encoding unit 1000 based on the split mode mode information May be a corresponding partitioning method.

For example, the image decoding apparatus 100 can determine the third encoding units 1012a and 1012b in the form of a square by dividing the left second encoding unit 1010a in the horizontal direction and the right second encoding unit 1010b It is possible to determine the third encoding units 1014a and 1014b in the form of a square by being divided in the horizontal direction. Further, the image decoding apparatus 100 may divide the left second encoding unit 1010a and the right second encoding unit 1010b in the horizontal direction to determine the third encoding units 1016a, 1016b, 1016c, and 1016d in the form of a square have. In this case, the encoding unit may be determined in the same manner as the first encoding unit 1000 is divided into the four second square encoding units 1030a, 1030b, 1030c, and 1030d.

 In another example, the image decoding apparatus 100 can determine the third encoding units 1022a and 1022b in the shape of a square by dividing the upper second encoding unit 1020a in the vertical direction, and the lower second encoding units 1020b Can be divided in the vertical direction to determine the third encoding units 1024a and 1024b in the form of a square. Furthermore, the image decoding apparatus 100 may divide the upper second encoding unit 1020a and the lower second encoding unit 1020b in the vertical direction to determine the third encoding units 1022a, 1022b, 1024a, and 1024b in the form of a square have. In this case, the encoding unit may be determined in the same manner as the first encoding unit 1000 is divided into the four second square encoding units 1030a, 1030b, 1030c, and 1030d.

11 illustrates that the processing order among a plurality of coding units may be changed according to the division process of the coding unit according to an embodiment.

According to an embodiment, the image decoding apparatus 100 may divide the first encoding unit 1100 based on the division type mode information. When the block type is square and the division type mode information indicates that the first encoding unit 1100 is divided into at least one of a horizontal direction and a vertical direction, the image decoding apparatus 100 may generate the first encoding unit 1100 (For example, 1110a, 1110b, 1120a, 1120b, 1130a, 1130b, 1130c, 1130d, etc.) 11, the non-square second encoding units 1110a, 1110b, 1120a, and 1120b, which are determined by dividing the first encoding unit 1100 only in the horizontal direction or the vertical direction, Can be divided independently. For example, the image decoding apparatus 100 divides the second encoding units 1110a and 1110b generated by dividing the first encoding unit 1100 in the vertical direction into the horizontal direction and outputs the third encoding units 1116a and 1116b, 1116c and 1116d can be determined and the second encoding units 1120a and 1120b generated by dividing the first encoding unit 1100 in the horizontal direction are respectively divided in the horizontal direction to generate third encoding units 1126a, 1126b and 1126c , 1126d. Since the process of dividing the second encoding units 1110a, 1110b, 1120a, and 1120b has been described in detail with reference to FIG. 9, a detailed description thereof will be omitted.

According to an embodiment, the image decoding apparatus 100 may process an encoding unit in a predetermined order. The features of the processing of the encoding unit according to the predetermined order have been described above with reference to FIG. 6, and a detailed description thereof will be omitted. 11, the image decoding apparatus 100 divides a first encoding unit 1100 in a square form into 4 pieces of fourth encoding units 1116a, 1116b, 1116c, 1116d, 1126a, 1126b, 1126c, 1126d Can be determined. According to one embodiment, the image decoding apparatus 100 may process the third encoding units 1116a, 1116b, 1116c, 1116d, 1126a, 1126b, 1126c, and 1126d according to the form in which the first encoding unit 1100 is divided You can decide.

According to an embodiment, the image decoding apparatus 100 divides the second encoding units 1110a and 1110b generated in the vertical direction into the horizontal direction to determine the third encoding units 1116a, 1116b, 1116c, and 1116d And the image decoding apparatus 100 first processes the third encoding units 1116a and 1116b included in the left second encoding unit 1110a in the vertical direction and then processes the third encoding units 1116a and 1116b included in the right second encoding unit 1110b The third encoding units 1116a, 1116b, 1116c, and 1116d may be processed in accordance with an order 1117 of processing the third encoding units 1116c and 1116d in the vertical direction.

According to an embodiment, the image decoding apparatus 100 divides the second encoding units 1120a and 1120b generated in the horizontal direction into vertical directions to determine the third encoding units 1126a, 1126b, 1126c, and 1126d And the image decoding apparatus 100 processes the third encoding units 1126a and 1126b included in the upper second encoding unit 1120a in the horizontal direction first and then processes the third encoding units 1126a and 1126b included in the lower second encoding unit 1120b The third encoding units 1126a, 1126b, 1126c, and 1126d can be processed according to the order 1127 of processing the third encoding units 1126c and 1126d in the horizontal direction.

Referring to FIG. 11, the second encoding units 1110a, 1110b, 1120a, and 1120b are divided to determine the third encoding units 1116a, 1116b, 1116c, 1116d, 1126a, 1126b, 1126c, and 1126d, have. The second encoding units 1110a and 1110b determined to be divided in the vertical direction and the second encoding units 1120a and 1120b determined to be divided in the horizontal direction are divided into different formats, but the third encoding units 1116a , 1116b, 1116c, 1116d, 1126a, 1126b, 1126c and 1126d, the result is that the first encoding unit 1100 is divided into the same type of encoding units. Accordingly, the image decoding apparatus 100 recursively divides an encoding unit through a different process based on division mode information, thereby eventually determining the same type of encoding units, It can be processed in order.

FIG. 12 illustrates a process of determining the depth of an encoding unit when the encoding unit is recursively divided and a plurality of encoding units are determined according to an embodiment.

According to an exemplary embodiment, the image decoding apparatus 100 may determine the depth of a coding unit according to a predetermined criterion. For example, a predetermined criterion may be a length of a long side of a coding unit. When the length of the long side of the current encoding unit is divided by 2n (n > 0) times longer than the length of the long side of the current encoding unit, the depth of the current encoding unit is smaller than the depth of the encoding unit before being divided it can be determined that the depth is increased by n. Hereinafter, an encoding unit with an increased depth is expressed as a lower-depth encoding unit.

Referring to FIG. 12, on the basis of block type information (for example, block type information may indicate '0: SQUARE') indicating that the block type information is a square type according to an embodiment, 1 encoding unit 1200 can be divided to determine the second encoding unit 1202, the third encoding unit 1204, and the like of the lower depth. If the size of the first encoding unit 1200 in the square form is 2Nx2N, the second encoding unit 1202 determined by dividing the width and height of the first encoding unit 1200 by 1/21 times has a size of NxN have. Furthermore, the third encoding unit 1204 determined by dividing the width and height of the second encoding unit 1202 by a half size may have a size of N / 2xN / 2. In this case, the width and height of the third encoding unit 1204 correspond to 1/22 times of the first encoding unit 1200. If the depth of the first encoding unit 1200 is D, the depth of the second encoding unit 1202, which is 1/21 times the width and height of the first encoding unit 1200, may be D + 1, The depth of the third encoding unit 1204, which is one-22 times the width and height of the third encoding unit 1200, may be D + 2.

According to an exemplary embodiment, block type information indicating a non-square shape (for example, block type information is' 1: NS_VER 'indicating that the height is a non-square having a width greater than the width or' 2), the image decoding apparatus 100 divides the first encoding unit 1210 or 1220 in a non-square form and outputs the second encoding unit 1212 or 1222 of the lower depth, The third encoding unit 1214 or 1224, or the like.

The image decoding apparatus 100 may determine a second encoding unit (e.g., 1202, 1212, 1222, etc.) by dividing at least one of the width and the height of the first encoding unit 1210 of Nx2N size. That is, the image decoding apparatus 100 can determine the second encoding unit 1202 of NxN size or the second encoding unit 1222 of NxN / 2 size by dividing the first encoding unit 1210 in the horizontal direction, The second encoding unit 1212 of N / 2xN size may be determined by dividing the second encoding unit 1212 in the horizontal direction and the vertical direction.

According to an embodiment, the image decoding apparatus 100 determines a second encoding unit (for example, 1202, 1212, 1222, etc.) by dividing at least one of the width and height of the 2NxN first encoding unit 1220 It is possible. That is, the image decoding apparatus 100 can determine the second encoding unit 1202 of NxN size or the second encoding unit 1212 of N / 2xN size by dividing the first encoding unit 1220 in the vertical direction, The second encoding unit 1222 of NxN / 2 size may be determined by dividing the image data in the horizontal direction and the vertical direction.

According to an embodiment, the image decoding apparatus 100 determines a third encoding unit (for example, 1204, 1214, 1224, etc.) by dividing at least one of the width and the height of the second encoding unit 1202 of NxN size It is possible. That is, the image decoding apparatus 100 determines the third encoding unit 1204 of N / 2xN / 2 size by dividing the second encoding unit 1202 in the vertical and horizontal directions, or determines the third encoding unit 1204 of N / 2xN / 3 encoding unit 1214 or a third encoding unit 1224 of N / 2xN / 2 size.

According to one embodiment, the image decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 1212 of N / 2xN size and encodes the third encoding unit (for example, 1204, 1214, 1224, . That is, the image decoding apparatus 100 divides the second encoding unit 1212 in the horizontal direction to generate a third encoding unit 1204 of N / 2xN / 2 or a third encoding unit 1224 of N / 2xN / 2 size ) Or may be divided in the vertical and horizontal directions to determine the third encoding unit 1214 of N / 2xN / 2 size.

According to an exemplary embodiment, the image decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 1214 of NxN / 2 size to generate a third encoding unit (e.g., 1204, 1214, 1224, etc.) . That is, the image decoding apparatus 100 divides the second encoding unit 1212 in the vertical direction to generate a third encoding unit 1204 of N / 2xN / 2 or a third encoding unit 1214 of N / 2xN / 2 size ) Or may be divided in the vertical and horizontal directions to determine the third encoding unit 1224 of N / 2xN / 2 size.

According to an embodiment, the image decoding apparatus 100 may divide a square-shaped encoding unit (for example, 1200, 1202, and 1204) in a horizontal direction or a vertical direction. For example, the first encoding unit 1200 having a size of 2Nx2N is divided in the vertical direction to determine a first encoding unit 1210 having a size of Nx2N or the first encoding unit 1210 having a size of 2NxN to determine a first encoding unit 1220 having a size of 2NxN . According to one embodiment, when the depth is determined based on the length of the longest side of the encoding unit, the depth of the encoding unit in which the first encoding unit 1200, 1202, or 1204 of size 2Nx2N is divided in the horizontal direction or the vertical direction is determined May be the same as the depth of the first encoding unit 1200, 1202 or 1204.

According to an embodiment, the width and height of the third encoding unit 1214 or 1224 may correspond to 1/2 of the first encoding unit 1210 or 1220. [ When the depth of the first coding unit 1210 or 1220 is D, the depth of the second coding unit 1212 or 1214 which is half the width and height of the first coding unit 1210 or 1220 is D + And the depth of the third encoding unit 1214 or 1224, which is half the width and height of the first encoding unit 1210 or 1220, may be D + 2.

FIG. 13 illustrates a depth index (hereinafter referred to as PID) for coding unit classification and depth that can be determined according to the type and size of coding units according to an exemplary embodiment.

According to an embodiment, the image decoding apparatus 100 may divide the first encoding unit 1300 in a square shape to determine various types of second encoding units. 13, the image decoding apparatus 100 divides the first encoding unit 1300 into at least one of a vertical direction and a horizontal direction according to the division type mode information, and outputs the second encoding units 1302a, 1302b, 1304a , 1304b, 1306a, 1306b, 1306c, and 1306d. That is, the image decoding apparatus 100 can determine the second encoding units 1302a, 1302b, 1304a, 1304b, 1306a, 1306b, 1306c, and 1306d based on the split mode mode information for the first encoding unit 1300 .

The second encoding units 1302a, 1302b, 1304a, 1304b, 1306a, 1306b, 1306c, and 1306d, which are determined according to the split mode mode information for the first encoded unit 1300 in the form of a square, The depth of field can be determined based on the depth. For example, since the length of one side of the square-shaped first encoding unit 1300 and the length of longer sides of the non-square-shaped second encoding units 1302a, 1302b, 1304a, and 1304b are the same, 1300) and the non-square type second encoding units 1302a, 1302b, 1304a, and 1304b are denoted by D in the same manner. On the other hand, when the image decoding apparatus 100 divides the first encoding unit 1300 into four square-shaped second encoding units 1306a, 1306b, 1306c, and 1306d based on the split mode information, Since the length of one side of the second coding units 1306a, 1306b, 1306c and 1306d is half the length of one side of the first coding unit 1300, the length of one side of the second coding units 1306a, 1306b, 1306c and 1306d The depth may be a depth of D + 1 that is one depth lower than D, which is the depth of the first encoding unit 1300.

According to an embodiment, the image decoding apparatus 100 divides a first coding unit 1310 having a height greater than a width in a horizontal direction according to division mode information, and generates a plurality of second coding units 1312a, 1312b, and 1314a , 1314b, and 1314c. According to an embodiment, the image decoding apparatus 100 divides a first coding unit 1320 having a shape whose width is longer than a height in a vertical direction according to division mode information, and generates a plurality of second coding units 1322a, 1322b, and 1324a , 1324b, and 1324c.

The second encoding units 1312a, 1312b, 1314a, 1314b, 1316a, 1316b, 1316c, and 1316d, which are determined according to the split mode mode information for the first encoding unit 1310 or 1320 in the non- The depth can be determined based on the length of the long side. For example, since the length of one side of the square-shaped second encoding units 1312a and 1312b is one-half the length of one side of the non-square first encoding unit 1310 whose height is longer than the width, The depth of the second encoding units 1302a, 1302b, 1304a, and 1304b of the form of D + 1 is one depth lower than the depth D of the first encoding unit 1310 of the non-square form.

Further, the image decoding apparatus 100 may divide the non-square first encoding unit 1310 into odd second encoding units 1314a, 1314b, and 1314c based on the division type mode information. The odd number of second encoding units 1314a, 1314b and 1314c may include non-square second encoding units 1314a and 1314c and a square second encoding unit 1314b. In this case, the long side of the non-square type second encoding units 1314a and 1314c and the length of one side of the second type encoding unit 1314b in the form of a square are set to 1/4 of the length of one side of the first encoding unit 1310, The depth of the second encoding units 1314a, 1314b, and 1314c may be a depth of D + 1 which is one depth lower than the depth D of the first encoding unit 1310. [ The image decoding apparatus 100 is connected to the first coding unit 1320 of a non-square shape having a width greater than the height in a manner corresponding to the method of determining the depths of the coding units associated with the first coding unit 1310 The depth of the encoding units can be determined.

According to an exemplary embodiment, the image decoding apparatus 100 determines an index (PID) for distinguishing the divided coding units. If the odd-numbered coding units are not the same size, The index can be determined based on the index. Referring to FIG. 13, an encoding unit 1314b positioned at the center among odd-numbered encoding units 1314a, 1314b, and 1314c has the same width as other encoding units 1314a and 1314c, May be twice as high as the height of the sidewalls 1314a, 1314c. That is, in this case, the middle encoding unit 1314b may include two of the other encoding units 1314a and 1314c. Accordingly, if the index (PID) of the coding unit 1314b located at the center is 1 according to the scanning order, the coding unit 1314c positioned next to the coding unit 1314c may be three days in which the index is increased by two. That is, there may be a discontinuity in the value of the index. According to an exemplary embodiment, the image decoding apparatus 100 may determine whether odd-numbered encoding units are not the same size based on the presence or absence of an index discontinuity for distinguishing between the divided encoding units.

According to an exemplary embodiment, the image decoding apparatus 100 may determine whether the image is divided into a specific division form based on an index value for distinguishing a plurality of coding units divided from the current coding unit. 13, the image decoding apparatus 100 divides a first coding unit 1310 of a rectangular shape whose height is longer than the width to determine even-numbered coding units 1312a and 1312b or odd-numbered coding units 1314a and 1314b , 1314c. The image decoding apparatus 100 may use an index (PID) indicating each coding unit in order to distinguish each of the plurality of coding units. According to one embodiment, the PID may be obtained at a sample of a predetermined position of each coding unit (e.g., the upper left sample).

According to an embodiment, the image decoding apparatus 100 may determine a coding unit of a predetermined position among the coding units determined by using the index for classifying the coding unit. When the division type mode information for the rectangular first type encoding unit 1310 having a height greater than the width is divided into three encoding units according to an embodiment, the image decoding apparatus 100 may encode the first encoding unit 1310, Can be divided into three coding units 1314a, 1314b, and 1314c. The image decoding apparatus 100 may assign an index to each of the three encoding units 1314a, 1314b, and 1314c. The image decoding apparatus 100 may compare the indexes of the respective encoding units in order to determine the middle encoding unit among the encoding units divided into odd numbers. The image decoding apparatus 100 encodes an encoding unit 1314b having an index corresponding to a middle value among the indices based on the indices of the encoding units by encoding the middle position among the encoding units determined by dividing the first encoding unit 1310 Can be determined as a unit. According to an exemplary embodiment, the image decoding apparatus 100 may determine an index based on a size ratio between coding units when the coding units are not the same size in determining the index for dividing the divided coding units . 13, the coding unit 1314b generated by dividing the first coding unit 1310 is divided into coding units 1314a and 1314c having the same width as the other coding units 1314a and 1314c but different in height Can be double the height. In this case, if the index (PID) of the coding unit 1314b located at the center is 1, the coding unit 1314c located next to the coding unit 1314c may be three days in which the index is increased by two. In this case, when the index increases uniformly and the increment increases, the image decoding apparatus 100 may determine that the image decoding apparatus 100 is divided into a plurality of encoding units including encoding units having different sizes from other encoding units. When the division type mode information indicates that the division type mode information is divided into an odd number of encoding units, the image decoding apparatus 100 determines that the encoding unit (for example, the middle encoding unit) at a predetermined position among the odd number of encoding units is different from the encoding units You can split the current encoding unit into a form. In this case, the image decoding apparatus 100 may determine an encoding unit having a different size by using an index (PID) for the encoding unit. However, the index and the size or position of the encoding unit at a predetermined position to be determined are specific for explaining an embodiment, and thus should not be construed to be limited thereto, and various indexes, positions and sizes of encoding units can be used Should be interpreted.

According to an exemplary embodiment, the image decoding apparatus 100 may use a predetermined data unit in which a recursive division of an encoding unit starts.

FIG. 14 shows that a plurality of coding units are determined according to a plurality of predetermined data units included in a picture according to an embodiment.

According to one embodiment, a predetermined data unit may be defined as a unit of data in which an encoding unit begins to be recursively segmented using segmentation mode information. That is, it may correspond to a coding unit of the highest depth used in a process of determining a plurality of coding units for dividing a current picture. Hereinafter, such a predetermined data unit is referred to as a reference data unit for convenience of explanation.

According to one embodiment, the reference data unit may represent a predetermined size and shape. According to one embodiment, the reference encoding unit may comprise samples of MxN. Here, M and N may be equal to each other, or may be an integer represented by a multiplier of 2. That is, the reference data unit may represent a square or a non-square shape, and may be divided into an integer number of encoding units.

According to an embodiment, the image decoding apparatus 100 may divide a current picture into a plurality of reference data units. According to an embodiment, the image decoding apparatus 100 may divide a plurality of reference data units for dividing a current picture by using the division information for each reference data unit. The segmentation process of the reference data unit may correspond to the segmentation process using a quad-tree structure.

According to an embodiment, the image decoding apparatus 100 may determine in advance the minimum size that the reference data unit included in the current picture can have. Accordingly, the image decoding apparatus 100 can determine reference data units of various sizes having a size larger than a minimum size, and can determine at least one encoding unit using the split mode information based on the determined reference data unit .

Referring to FIG. 14, the image decoding apparatus 100 may use a square-shaped reference encoding unit 1400 or a non-square-shaped reference encoding unit 1402. According to an exemplary embodiment, the type and size of the reference encoding unit may include various data units (e.g., a sequence, a picture, a slice, a slice segment a slice segment, a maximum encoding unit, and the like).

According to an embodiment, the receiver 160 of the video decoding apparatus 100 may acquire at least one of the information on the format of the reference encoding unit and the size of the reference encoding unit from the bitstream for each of the various data units . The process of determining at least one encoding unit included in the reference-type encoding unit 1400 in the form of a square is described in detail in the process of dividing the current encoding unit 300 of FIG. 10, Is determined in the process of dividing the current encoding unit 1100 or 1150 of FIG. 11, so that a detailed description thereof will be omitted.

In order to determine the size and the type of the reference encoding unit according to a predetermined data unit predetermined based on a predetermined condition, the image decoding apparatus 100 may include an index for identifying the size and type of the reference encoding unit Can be used. That is, the receiving unit 160 extracts a predetermined condition (for example, a data unit having a size equal to or smaller than a slice) among the various data units (for example, a sequence, a picture, a slice, a slice segment, It is possible to obtain only an index for identifying the size and type of the reference encoding unit for each slice, slice segment, maximum encoding unit, and the like. The image decoding apparatus 100 can determine the size and shape of the reference data unit for each data unit satisfying the predetermined condition by using the index. When the information on the type of the reference encoding unit and the information on the size of the reference encoding unit are obtained from the bitstream for each relatively small data unit and used, the use efficiency of the bitstream may not be good. Therefore, Information on the size of the reference encoding unit and information on the size of the reference encoding unit can be acquired and used. In this case, at least one of the size and the type of the reference encoding unit corresponding to the index indicating the size and type of the reference encoding unit may be predetermined. That is, the image decoding apparatus 100 selects at least one of the size and the type of the reference encoding unit in accordance with the index, thereby obtaining at least one of the size and the type of the reference encoding unit included in the data unit, You can decide.

According to an exemplary embodiment, the image decoding apparatus 100 may use at least one reference encoding unit included in one maximum encoding unit. That is, the maximum encoding unit for dividing an image may include at least one reference encoding unit, and the encoding unit may be determined through a recursive division process of each reference encoding unit. According to an exemplary embodiment, at least one of the width and the height of the maximum encoding unit may correspond to at least one integer multiple of the width and height of the reference encoding unit. According to an exemplary embodiment, the size of the reference encoding unit may be a size obtained by dividing the maximum encoding unit n times according to a quadtree structure. That is, the image decoding apparatus 100 may determine the reference encoding unit by dividing the maximum encoding unit n times according to the quad tree structure, and may determine the reference encoding unit based on at least one of the division mode information Can be divided.

FIG. 15 shows a processing block serving as a reference for determining a determination order of a reference encoding unit included in a picture 1500 according to an embodiment.

According to one embodiment, the image decoding apparatus 100 may determine at least one processing block that divides a picture. The processing block is a data unit including at least one reference encoding unit for dividing an image, and at least one reference encoding unit included in the processing block may be determined in a specific order. That is, the order of determination of at least one reference encoding unit determined in each processing block may correspond to one of various kinds of order in which the reference encoding unit can be determined, and the reference encoding unit determination order determined in each processing block May be different for each processing block. The order of determination of the reference encoding unit determined for each processing block is a raster scan, a Z scan, an N scan, an up-right diagonal scan, a horizontal scan a horizontal scan, and a vertical scan. However, the order that can be determined should not be limited to the scan orders.

According to an embodiment, the image decoding apparatus 100 may obtain information on the size of the processing block and determine the size of the at least one processing block included in the image. The image decoding apparatus 100 may obtain information on the size of the processing block from the bitstream to determine the size of the at least one processing block included in the image. The size of such a processing block may be a predetermined size of a data unit represented by information on the size of the processing block.

According to an embodiment, the receiving unit 160 of the image decoding apparatus 100 may obtain information on the size of the processing block from the bitstream for each specific data unit. For example, information on the size of a processing block can be obtained from a bitstream in units of data such as an image, a sequence, a picture, a slice, a slice segment, or the like. That is, the receiving unit 160 may acquire information on the size of the processing block from the bitstream for each of the plurality of data units, and the image decoding apparatus 100 may use at least the information on the size of the obtained processing block The size of one processing block may be determined, and the size of the processing block may be an integer multiple of the reference encoding unit.

The image decoding apparatus 100 may determine the sizes of the processing blocks 1502 and 1512 included in the picture 1500 according to an embodiment. For example, the video decoding apparatus 100 can determine the size of the processing block based on information on the size of the processing block obtained from the bitstream. 15, the image decoding apparatus 100 according to an exemplary embodiment of the present invention has a horizontal size of the processing blocks 1502 and 1512 of four times the horizontal size of the reference encoding unit, a vertical size of four times the vertical size of the reference encoding unit You can decide. The image decoding apparatus 100 may determine an order in which at least one reference encoding unit is determined in at least one processing block.

According to one embodiment, the video decoding apparatus 100 may determine each processing block 1502, 1512 included in the picture 1500 based on the size of the processing block and may include in the processing blocks 1502, The determination order of at least one reference encoding unit is determined. The determination of the reference encoding unit may include determining the size of the reference encoding unit according to an embodiment.

According to an exemplary embodiment, the image decoding apparatus 100 may obtain information on a determination order of at least one reference encoding unit included in at least one processing block from a bitstream, So that the order in which at least one reference encoding unit is determined can be determined. The information on the decision order can be defined in the order or direction in which the reference encoding units are determined in the processing block. That is, the order in which the reference encoding units are determined may be independently determined for each processing block.

According to one embodiment, the image decoding apparatus 100 may obtain information on a determination order of a reference encoding unit from a bitstream for each specific data unit. For example, the receiving unit 160 may acquire information on the order of determination of a reference encoding unit from a bitstream for each data unit such as an image, a sequence, a picture, a slice, a slice segment, and a processing block. Since the information on the determination order of the reference encoding unit indicates the reference encoding unit determination order in the processing block, the information on the determination order can be obtained for each specific data unit including an integer number of processing blocks.

The image decoding apparatus 100 may determine at least one reference encoding unit based on the determined order according to an embodiment.

According to an embodiment, the receiving unit 160 may obtain information on the reference encoding unit determination order from the bitstream as the information related to the processing blocks 1502 and 1512, and the video decoding apparatus 100 may receive the information 1502, and 1512, and determine at least one reference encoding unit included in the picture 1500 according to the determination order of the encoding units. Referring to FIG. 15, the video decoding apparatus 100 may determine a determination order 1504 and 1514 of at least one reference encoding unit associated with each of the processing blocks 1502 and 1512. For example, when information on the determination order of reference encoding units is obtained for each processing block, the reference encoding unit determination order associated with each processing block 1502 and 1512 may be different for each processing block. If the reference encoding unit determination order 1504 related to the processing block 1502 is a raster scan order, the reference encoding unit included in the processing block 1502 may be determined according to the raster scan order. On the other hand, when the reference encoding unit determination order 1514 related to another processing block 1512 is a reverse order of the raster scan order, the reference encoding unit included in the processing block 1512 can be determined according to the reverse order of the raster scan order.

The image decoding apparatus 100 may decode the determined at least one reference encoding unit according to an embodiment. The image decoding apparatus 100 can decode an image based on the reference encoding unit determined through the above-described embodiment. The method of decoding the reference encoding unit may include various methods of decoding the image.

According to an exemplary embodiment, the image decoding apparatus 100 may obtain block type information indicating a type of a current encoding unit or divided mode type information indicating a method of dividing a current encoding unit from a bitstream. The split mode information may be included in a bitstream associated with various data units. For example, the video decoding apparatus 100 may include a sequence parameter set, a picture parameter set, a video parameter set, a slice header, a slice segment header slice segment type mode information included in the segment header can be used. Further, the image decoding apparatus 100 may obtain a syntax element corresponding to the maximum encoding unit, the reference encoding unit, the block type information from the bitstream or the split mode information for each processing block from the bitstream and use the obtained syntax element.

Hereinafter, a method of determining a partitioning rule according to an embodiment of the present disclosure will be described in detail.

The image decoding apparatus 100 can determine the division rule of the image. The segmentation rule may be previously determined between the image decoding apparatus 100 and the image encoding apparatus 3800. The image decoding apparatus 100 can determine the division rule of the image based on the information obtained from the bit stream. The video decoding apparatus 100 includes a sequence parameter set, a picture parameter set, a video parameter set, a slice header, and a slice segment header The partitioning rule can be determined based on the information obtained from at least one. The video decoding apparatus 100 may determine the division rule differently according to a frame, a slice, a temporal layer, a maximum encoding unit, or an encoding unit.

The image decoding apparatus 100 can determine the division rule based on the block type of the encoding unit. The block shape may include the size, shape, width and height ratio, direction of the encoding unit. The video encoding device 3800 and the video decoding device 100 can determine in advance that the division rule is determined based on the block type of the encoding unit. However, the present invention is not limited thereto. The video decoding apparatus 100 can determine the division rule based on the information obtained from the bit stream received from the video encoding apparatus 3800. [

The shape of the encoding unit may include a square and a non-square. If the width and height of the encoding unit are the same, the image decoding apparatus 100 can determine the shape of the encoding unit as a square. Also, . If the lengths of the widths and heights of the coding units are not the same, the image decoding apparatus 100 can determine the shape of the coding unit to be non-square.

The size of the encoding unit may include various sizes of 4x4, 8x4, 4x8, 8x8, 16x4, 16x8, ..., 256x256. The size of the encoding unit can be classified according to the length of the longer side of the encoding unit, the length or the width of the shorter side. The video decoding apparatus 100 may apply the same division rule to the coding units classified into the same group. For example, the image decoding apparatus 100 may classify encoding units having the same long side length into the same size. In addition, the image decoding apparatus 100 can apply the same division rule to coding units having the same long side length.

The ratio of the width and height of the encoding unit may include 1: 2, 2: 1, 1: 4, 4: 1, 1: 8, 8: 1, 1:16 or 16: 1. In addition, the direction of the encoding unit may include a horizontal direction and a vertical direction. The horizontal direction may indicate the case where the length of the width of the encoding unit is longer than the length of the height. The vertical direction can indicate the case where the width of the encoding unit is shorter than the length of the height.

The image decoding apparatus 100 may adaptively determine the segmentation rule based on the size of the encoding unit. The image decoding apparatus 100 may determine the allowable division mode differently based on the size of the encoding unit. For example, the image decoding apparatus 100 can determine whether division is allowed based on the size of an encoding unit. The image decoding apparatus 100 can determine the dividing direction according to the size of the coding unit. The video decoding apparatus 100 can determine an allowable division type according to the size of a coding unit.

Determination of the division rule based on the size of the encoding unit may be a predetermined division rule between the video encoding device 3800 and the video decoding device 100. [ Further, the video decoding apparatus 100 can determine the division rule based on the information obtained from the bit stream.

The image decoding apparatus 100 can adaptively determine the division rule based on the position of the encoding unit. The image decoding apparatus 100 may adaptively determine the segmentation rule based on the position occupied by the encoding unit in the image.

In addition, the image decoding apparatus 100 can determine the division rule so that the encoding units generated by different division paths do not have the same block form. However, the present invention is not limited thereto, and coding units generated by different division paths may have the same block form. The coding units generated by different division paths may have different decoding processing orders. The decoding procedure is described with reference to FIG. 11, and a detailed description thereof will be omitted.

16 to 39, the current block is divided into a plurality of zones and a plurality of sub-zones, a context, a scanning order, a coefficient coding scheme and the like are determined according to the division type of the current block and the characteristics of the conversion coefficient array, A scanning order, and a coefficient coding method, a method of coding or decoding a transform coefficient array of a current block will be described.

FIG. 16 shows a block diagram of a video decoding apparatus 1600 for obtaining a transform coefficient array of a current block based on a plurality of regions and a plurality of sub regions in which the current block is divided.

The video decoding apparatus 1600 includes an encoding information receiving unit 1610 and an entropy decoding unit 1620. 16, the encoding information receiving unit 1610 and the entropy decoding unit 1620 are represented as separate constituent units. However, according to the embodiment, the encoding information receiving unit 1610 and the entropy decoding unit 1620 are combined to form a single unit .

16, the encoding information receiving unit 1610 and the entropy decoding unit 1620 are represented by a unit located in one device. However, an apparatus that performs the functions of the encoding information receiving unit 1610 and the entropy decoding unit 1620 must be physically . Therefore, the encoding information receiving unit 1610 and the entropy decoding unit 1620 may be dispersed according to the embodiment.

The encoding information receiving unit 1610 and the entropy decoding unit 1620 may be implemented by one processor according to the embodiment. And may be implemented by a plurality of processors according to an embodiment.

The encoding information receiving unit 1610 receives the bit stream including the zone flag, the sub zone flag, and the transform coefficient information of the current block. The current block may be an encoding unit or a conversion unit for encoding and decoding the transform coefficients. A zone flag, sub-zone flag, and transform coefficient information may be used by the entropy decoding unit 1620 to reconstruct the two-dimensional transform coefficient array of the current block.

The entropy decoding unit 1620 divides the current block into a plurality of zones. Dimensional transformed coefficient array of the current block can be generated when a 2D residual sample array showing the difference between the original value and the predicted value of the samples included in the current block is frequency-transformed. The transform coefficient located on the upper left of the two-dimensional transform coefficient array of the current block represents a low-frequency component, and the transform coefficient located on the lower-right side represents a high-frequency component. Since the magnitude of the low-frequency component is statistically larger than the magnitude of the high-frequency component, the transform coefficient of the upper left side in the two-dimensional transform coefficient array of the current block has an absolute value larger than the transform coefficient of the lower right side. In the quantization process, since the lower-order transform coefficient having a relatively small absolute value is determined to be 0, the probability that the effective transform coefficient having an absolute value larger than 1 is distributed to the upper left of the current block is high. Therefore, by dividing the current block according to the probability of occurrence of effective transform coefficients and applying a different decoding method to each divided region, it is possible to efficiently compress the two-dimensional transform coefficient array of the current block.

According to one embodiment, the entropy decoding unit 1620 can determine the current block as a region having a predetermined region size regardless of the size of the current block. Then, the entropy decoding unit 1620 can determine the remaining region excluding the regions having the predetermined region size in the current block as the last region of the current block.

According to another embodiment, the entropy decoding unit 1620 may determine the current block as a region having a zone size proportional to the size of the current block. The entropy decoding unit 1620 can determine the remaining region excluding the regions having the predetermined region size in the current block as the last region of the current block.

The entropy decoding unit 1620 can determine the number of regions to be divided according to the size of the current block. For example, when the size of the current block is 4x4, the current block may contain only one region of 4x4 size. And, when the size of the current block is larger than 4x4, the current block can be divided into two or more zones. As another example, when the greater of the height and width of the current block is greater than 4, the current block may be divided into two or more zones. As another example, when the greater of the height and width of the current block is greater than eight, the current block may be divided into three or more zones.

The entropy decoding unit 1620 decodes the entropy of the current block including the block index, the current block size, the conversion unit size, the encoding unit size, the encoded block type (e.g., intra / inter), the component type (e.g., luma / chroma) Mode, prediction mode), the context of the current block can be determined. According to one embodiment, the entropy decoding unit 1620 can determine the context of the current block according to a smaller value of the height and width of the current block or a greater value of the height and width of the current block. The entropy decoding unit 1620 can parse the zone flag obtained from the bitstream according to the context of the current block.

The entropy decoding unit 1620 determines, based on the zone flags for the plurality of zones of the current block, which of the plurality of zones the last valid conversion coefficient of the current block is included in. The effective conversion coefficient is a conversion coefficient whose absolute value of the coefficient is not zero. The position of the last effective transform coefficient of the current block is determined based on the position of the last effective transform coefficient in accordance with the scan order of the current block.

The zone flag indicates whether the current zone contains the last valid conversion factor of the current block. The zone flag can be represented by one bit. And a zone flag for the zone including the last valid conversion coefficient of the current block is represented by a first value and a zone flag of the remaining zone is represented by a second value. Or the zone flag for the zone including the last sub-zone including the effective conversion coefficient of the current block may be represented by the first value, and the zone flag of the remaining zone may be represented by the second value. The first value may be one and the second value may be zero.

The zone flags of the zones of the current block are parsed according to the scan order. For example, when scanned in order of the first zone, the second zone, and the third zone, the zone flag of the first zone is first obtained from the bitstream. If the zone flag of the first zone represents the first value, it is determined that the first zone contains the last effective conversion coefficient of the current block. Therefore, since the last valid conversion coefficient of the current block is not included in the remaining second and third zones, the zone flag for the second zone and the zone flag for the third zone are not acquired.

If the zone flag of the first zone represents the second value, it is determined that the first effective zone conversion coefficient of the current block is not included in the first zone. Thus, a zone flag of the second zone is obtained from the bitstream. If the zone flag of the second zone represents the first value, it is determined that the second zone includes the last effective conversion coefficient of the current block. Therefore, the zone flag for the third zone is not acquired because the last effective conversion coefficient of the current block is not included in the third zone. Conversely, if the zone flag of the second zone represents a second value, it is determined that the last effective transform coefficient of the current block is not included in the second zone. In accordance with the zone flag for the third zone, it is determined whether or not the third zone includes the last effective conversion coefficient of the current block.

If the third zone is the last zone of the current block according to the scan order, whether or not the last effective transform coefficient of the current block is included in the third zone according to the zone flag of the second zone without the zone flag of the third zone Can be determined. For example, if the second zone includes the last valid conversion factor of the current block, the third zone does not include the last valid conversion factor of the current block. Conversely, if the second zone does not include the last effective transform coefficient of the current block, the third zone necessarily includes the last effective transform coefficient of the current block. Thus, it can be determined whether or not the last zone contains the last effective transform coefficient of the current block, without acquiring the zone flag of the last zone of the current block.

If the number of zones of the current block is determined according to the size of the current block, the maximum number of zone flags that can be acquired for the current block may be determined according to the size of the current block. For example, the number of zones included in the current block can be determined by comparing a large value or a small value of the height and width of the current block with a predetermined value. According to one embodiment, if the greater of the height and width of the current block is greater than eight, the current block may be divided into three zones. In this condition, a maximum of two zone flags of the current block may be required. Conversely, if the greater of the height and width of the current block is equal to 8, the current block can be divided into two zones. In this condition, one zone flag of the current block is required.

The entropy decoding unit 1620 divides an area into which at least one effective transform coefficient of the plurality of regions can be included into a plurality of subzones.

The entropy decoding unit 1620 may divide the current region into sub regions according to a predetermined sub region size. Or the entropy decoding unit 1620 may divide the current region into sub regions according to the size of the current block.

The entropy decoding unit 1620 can determine the number of sub-regions to be divided from the current zone according to the size of the current zone.

The entropy decoding unit 1620 determines whether at least one valid conversion coefficient is included for each of the plurality of sub zones according to the sub zone flags for the plurality of sub zones of the current block. Hereinafter, the effective sub-zone is a sub-zone including at least one effective conversion coefficient.

The subspace flag indicates whether the current subspace contains an effective transform coefficient. The sub-zone flag can be represented by 1 bit. The subspace flag of the subspace containing the effective transformation coefficient is represented by a first value and the subspace flag of the subspace including no effective transformation coefficient may be represented by a second value. The first value may be one and the second value may be zero.

The sub-zone flags of the sub-zones included in the zones are parsed according to the scan order. For example, when scanned in the order of the first sub-zone, the second sub-zone and the third sub-zone, the sub-zone flag of the first sub-zone is first obtained from the bit stream. Sub-zone flags of the second sub-zone and the third sub-zone are obtained according to the scan order.

If the third sub-zone is the last sub-zone of the current zone, the current zone contains the last valid conversion factor, and the first sub-zone and the second sub-zone are not valid sub-zones, The third sub-zone without acquisition is determined as an effective sub-zone. If the current zone includes the last effective transform coefficient, at least one effective transform coefficient should be included in the current zone. Therefore, if the effective transform coefficients are not included in the first sub zone and the second sub zone, The zone must contain the effective conversion factor.

If the current zone includes only one sub-zone, and the current zone includes the last valid conversion factor, then the sub-zone must include at least one effective conversion factor. Thus, without obtaining the subarea flag under the above conditions, the subarea can be determined as an effective subarea.

Also, if low frequency conversion coefficients are located in the current zone, the probability that the sub-zone will contain the effective transform coefficients is very high. Therefore, even under the above conditions, it can be determined that the effective conversion coefficient is included in the sub zone without obtaining the sub zone flag. For example, if the current zone is located on the upper left of the two-dimensional transform coefficient array, the low-frequency transform coefficients are located in the current zone. Therefore, it can be determined that the sub-zone flag is not acquired and the effective sub-zone included in the current sub-zone is included in the effective sub-zone because the current zone is highly likely to have the effective conversion coefficient.

The entropy decoding unit 1620 can parse the transform coefficient information of the sub region obtained from the bit stream to obtain the transform coefficient of the sub region if the sub region flag indicates that the sub region includes the effective transform coefficient.

However, the entropy decoding unit 1620 does not parse the transform coefficient information for a region scanned after the region including the last valid transform coefficient. All of the transform coefficients included in the zone are set to zero. For example, if the second zone contains the last effective conversion factor, the conversion coefficients of the zones scanned after the second zone are all determined to be zero.

Also, the entropy decoding unit 1620 does not parse the transform coefficient for the sub-region determined to have no effective transform coefficient according to the sub-region flag. Therefore, all the transform coefficients of the subarea are determined to be zero. For example, if it is determined that the sub-zone flag of the first sub-zone does not have an effective conversion factor in the sub-zone, the conversion coefficients of the first sub-zone are all determined to be zero.

The entropy decoding unit 1620 decodes the entropy decoding result of the encoding unit 1620 based on the area index, the zone flag, the sub-zone index, the sub-zone flag, the current block size, Luma / chroma), prediction information (e.g., partition mode, prediction mode), and the like. According to one embodiment, the entropy decoding unit 1620 can determine the context of the current block according to a smaller value of the height and width of the current block or a greater value of the height and width of the current block. The entropy decoding unit 1620 may parse the sub-region flag obtained from the bit stream according to the context of the current block.

The entropy decoding unit 1620 can determine a coefficient coding scheme for a subarea including at least one effective transform coefficient among the plurality of subareas based on the zone flag and the subarea flag.

According to an exemplary embodiment, when the last effective transform coefficient of the current block is not included in the region including the sub-region, the entropy decoding unit 1620 performs the coefficient-coding method for the sub-region according to the first run- (Run-level based coefficient coding scheme).

In contrast, when the last effective transform coefficient of the current block is included in a zone including the sub-zone, the entropy decoding unit 1620 can determine the coefficient coding scheme for the sub-zone as the second run-level based coefficient coding scheme.

Run information that indicates the number of consecutive zero coefficients in the first run-level-based coefficient coding scheme, level information that indicates the absolute value of the coefficient of the topic, and sign information that indicates the sign of the coefficient The transform coefficients of the subspace are encoded and decoded using sign information.

Level information and the sign information in the second run-level-based coefficient coding scheme, coefficient information as a last item indicating whether the coefficient of the current topic is the coefficient of the last item of the sub- coefficient information is used to encode and decode the transform coefficients of the subspace.

According to an embodiment, the entropy decoding unit 1620 may perform a coefficient-coding scheme for a sub-zone based on a first run-level-based method, regardless of whether the last effective transform coefficient of the current block is included in a zone including the sub- Coefficient-based coding method or a second run-level-based coefficient-coding method.

According to one embodiment, the entropy decoding unit 1620 divides the current block into the first zone, the second zone and the third zone in the order close to the upper left side of the current block, and determines a coefficient coding scheme for each zone differently have.

For example, if the last effective transform coefficient is included in the first zone closest to the upper left of the current block, the entropy decoding unit 1620 may convert the subspace of the first zone into the last position-based coding scheme coefficient coding scheme. Or less than one sub-region in which the effective transform coefficient is included in the sub-regions of the second sub-region, the entropy decoding unit 1620 may decode the sub-region of the first sub-region according to the last position-based coefficient coding scheme. If all of the above conditions are not satisfied, the entropy decoding unit 1620 may decode the subregion of the first zone according to the full position-based coefficient coding scheme.

If the second region includes the last effective transform coefficient, the entropy decoding unit 1620 can decode the subregion of the second region according to a scan region-based coefficient coding scheme. If all of the above conditions are not satisfied, the entropy decoding unit 1620 can decode the subregion of the second zone according to the last location-based coefficient coding scheme.

And, the entropy decoding unit 1620 can decode the subregion of the third zone according to the scan area-based coefficient coding without any condition.

The entropy decoding unit 1620 may apply coefficient coding schemes different from the above-described embodiment to the sub-zones according to the conditions according to the zone flag and sub-zone flag.

The entropy decoding unit 1620 calculates the number of effective sub-zones, the intra mode, the current block size, the conversion unit size, the encoding unit size, the conversion skip state, the encoded block type (E.g., intra / inter), component type (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode), and so on. The entropy decoding unit 1620 may determine a diagonal scan, a zigzag scan, a horizontal scan, a vertical scan, or a combination thereof in the scanning order of the current sub-zone.

The scan order of the sub-regions may be determined independently of the scan order of the other sub-regions. Or the scan order of the subareas may be determined dependent on the scan order of the other subareas included in the zone.

The scan order of the sub-zones may be determined according to the number of valid sub-zones. A valid sub-zone is a sub-zone in which the transform coefficients may be included according to the size of the current block. According to one embodiment, an 8x8 block may include 4 sub-zones of 4x4 size. In this case, the scan order of the four sub-zones included in the 8x8 block may be determined according to the first adaptive scan order determination method. According to one embodiment, an MxN-sized block larger than 8x8 is divided into 4 sub-zones of 4x4 size, 2 sub-zones of (N-8) Х4 size, 2 blocks of 4Х (N-8) Lt; RTI ID = 0.0 > (N-8) < / RTI > In this case, the scan order of the nine sub-blocks included in the MxN-sized block may be determined according to the second adaptive scan order determination method.

If the effective coefficients are included in the upper two sub-regions and the effective coefficients are not included in the lower two sub-regions, the scan order of the two upper sub-regions may be determined as a horizontal scan. In addition, when the effective coefficients are included in the two sub-regions on the left side and the effective coefficients are not included in the two sub-regions on the right side, the scan order of the two left sub-regions can be determined as a vertical scan.

According to the second adaptive scan order determination method, when the effective coefficients are included in the upper three sub-regions and the effective coefficients are not included in the remaining sub-regions, the scan order of the three upper sub-regions is determined as a horizontal scan . Also, when the effective coefficients are included in the three sub-regions on the left side and the effective coefficients are not included in the remaining sub-regions, the scan order of the three sub-regions on the left side can be determined as a horizontal scan.

The entropy decoding unit 1620 obtains the transform coefficient array of the current block by parsing the transform coefficient information of the current block according to at least one of the scan order and the coefficient coding scheme.

The entropy decoding unit 1620 can determine the context of the current sample according to the size of one or more transform coefficients restored before the current sample. According to one embodiment, when the coefficient coding scheme of the subspace is a run-level based coefficient coding scheme, the entropy decoding unit 1620 may calculate the context of the current sample according to the size of one or more transform coefficients restored before the current sample You can decide.

For example, the context of the current sample can be determined according to the magnitude of the transform coefficient immediately before the effective transform coefficient. Or the context of the current sample may be determined according to the sum of the magnitudes of the predetermined number of transform coefficients immediately before the effective transform coefficients.

And the context of the current sample may be determined according to the average of the level of the last coded transform coefficient of the upper sub-zone of the current sub-zone and the level of the last coded transform coefficient of the left sub-zone of the current sub-zone. Or the level of the last encoded transform coefficient of the upper sub-zone of the current sub-zone and the level of the last encoded coefficient of the left sub-zone of the current sub-zone, whichever is smaller. Or the context of the current sample may be determined according to the greater of the level of the last encoded coefficient in the upper sub-zone of the current sub-zone and the level of the last encoded coefficient in the left sub-zone of the current sub-zone.

If the scan order is reverse (if the lower-right sub-zone is first decoded), the level of the last coded transform coefficient of the right sub-zone of the current sub-zone and the last encoded transform coefficient of the lower sub- The context of the current sample can be determined according to the average of the levels of the current sample. Or the level of the last coded transform coefficient of the lower sub-zone of the current sub-zone and the level of the last coded transform coefficient of the right sub-zone of the current sub-zone, whichever is smaller. Or the context of the current sample may be determined according to the greater of the level of the last coded transform coefficient of the lower sub-zone of the current sub-zone and the level of the last coded transform coefficient of the right sub-zone of the current sub-zone.

The entropy decoding unit 1620 can obtain the transform coefficient array of the current subspace by parsing the transform coefficient information of the current subspace according to the context of the current sample and the coefficient coding scheme of the current subspace.

Figs. 17 to 19 show embodiments in which a square current block having a size of N 占 N N is divided into a plurality of zones and sub-zones, and the transform coefficient information of the current block is parsed.

Figure 17 shows the zones and sub-zones according to the first embodiment. The current block 1700 can be divided into three horizontally sized 4, 4, N-8, and vertically divided into three sizes 4, 4, and N-8. Accordingly, the current block 1700 includes four blocks 1702, 1704, 1706 and 1708 of size 4 X 4, two blocks 1710 and 1712 of size N-8 X 4, and 2 blocks of size 4 X (N-8) Blocks 1714 and 1716 and one block 1718 of size (N-8) X (N-8).

The probability that the effective transformation coefficient is distributed in the block 1702 of the size 4 X 4 on the upper left side is very high. Thus, the first zone of the current block 1700 may be set to include only the block 1702 as a subarea. The probability that the effective transform coefficient is distributed more than the block 1702 of the upper left side size 4 X 4 is allocated to the block 1704 of the upper side size 4 X 4, the block 1706 of the left side size 4 X 4, and the block 1708 of the central size 4 X 4 1712, 1714, 1716, and 1718), the second zone of the current block 1700 is divided into three blocks 1704 of size 4 < RTI ID = 0.0 > , 1706, 1708). And the third zone of the current block 1700 may be set to include the remainder blocks 1710, 1712, 1714, 1716, and 1718 having a low probability that the effective transformation coefficient is distributed as a subarea.

In the first embodiment, the block size used for determination of the blocks 1702, 1704, 1706, and 1708 of the current block 1700 is set to 4x4, but it may be set to another size depending on the implementation. The block size may be a predetermined value or may be specified in a slice header, a picture parameter set (PPS), and a sequence parameter set (SPS).

Figure 18 shows zones and sub-zones according to a second embodiment. The current block 1800 can be divided into four horizontally sized 4, 4, 4, and N-12, and vertically divided into 4, 4, 4, and N-12. Thus, the current block 1800 includes blocks 1802, 1804, 1806, 1808, 1810, 1812, 1814, 1816 and 1818 of nine sizes 4 X 4, blocks 1820, 1822, 1824, a block 1826, 1828, and 1830, which are three sizes 4X (N-12), and a block 1832, which is one size N-12X (N-12).

The first zone of the current block 1800 may be set to include only the block 1802 in which the effective transformation coefficient is likely to be distributed as a subspace. And the second zone of the current block 1800 may include blocks 1804, 1806, 1808, 1810, and 1812 with a middle probability that the effective transform coefficient is distributed as a sub-zone. Finally, the third zone of the current block 1800 includes the remaining blocks 1814, 1816, 1818, 1820, 1822, 1824, 1826, 1828, 1830, 1832, can do.

In the second embodiment, the block size used for determination of the blocks 1802, 1804, 1806, 1808, 1810, 1812, 1814, 1816 and 1818 of the current block 1800 is set to 4x4, . ≪ / RTI > The block size may be a predetermined value or may be specified in a slice header, a picture parameter set (PPS), and a sequence parameter set (SPS).

FIG. 19 shows zones and sub-zones according to the third embodiment. The current block 1900 can be divided into four horizontally sized 4, 4, 4, and N-12, and vertically divided into 4, 4, 4, and N-12. Thus, the current block 1900 includes blocks 192, 1904, 1906, 1908, 1910, 1912, 1914, 1916, and 1918 having nine sizes 4 X 4, blocks 1920, 1924), blocks 1926, 1928, and 1930 of three sizes 4X (N-12), and a block 1932 of one size (N-12) X (N-12).

The first zone of the current block 1900 may be set to include only the block 1902 in which the effective transformation coefficient is likely to be distributed as a subspace. And the second zone of the current block 1900 may include the blocks 1804 and 1806 that are the second highest probability that the effective transform coefficient is distributed as a sub-zone. The ninth zone of the current block 1900 may include blocks 1808, 1810, and 1812 that are the second highest probability that the effective transform coefficient is distributed as a sub-zone. Finally, the fourth zone of the current block 1900 includes the remaining blocks 1814, 1816, 1818, 1820, 1822, 1824, 1826, 1828, 1830, 1832, can do.

Although the block size used for determination of the blocks 1902, 1904, 1906, 1908, 1910, 1912, 1914, 1916, and 1918 of the current block 1900 is set to 4x4 in the third embodiment, . ≪ / RTI > The block size may be a predetermined value or may be specified in a slice header, a picture parameter set (PPS), and a sequence parameter set (SPS).

FIGS. 20 and 21 disclose embodiments in which a rectangular current block having a size of M X N is divided into a plurality of zones and sub-zones, and the transform coefficient information of the current block is parsed.

FIG. 20 shows zones and sub-zones according to a fourth embodiment. In the fourth embodiment shown in Fig. 20, blocks having four sizes of 4x4 are divided from the upper left side of the current block, as in the first embodiment shown in Fig. That is, the current block 2000 can be divided into three horizontally sized 4, 4, and M-8, and vertically divided into 4, 4, and N-8. Therefore, the current block 2000 is composed of four blocks 2002, 2004, 2006 and 2008 of size 4 X 4, two blocks 2010 and 2012 of size M-8 X 4, Blocks 2014 and 2016, and one block 2018 of size (M-8) X (N-8).

As in the first embodiment, the first zone of the current block 2000 may be set to include only the block 2002 as a sub-zone. And the second zone of the current block 2000 may be set to include three blocks 2004, 2006, 2008 of size 4 X 4 as sub-zones. The third zone of the current block 2000 may be set to include the remaining blocks 2010, 2011, 2014, 2014, 2016, 2018 having a low probability of distribution of the effective transformation coefficient as a sub-zone.

In the fourth embodiment, the block size used for determination of the blocks 2002, 2004, 2006, 2008 of the current block 2000 is set to 4x4, but it may be set to another size according to the embodiment. The block size may be a predetermined value or may be specified in a slice header, a picture parameter set (PPS), and a sequence parameter set (SPS).

21 shows the zones and sub-zones according to the fifth embodiment. In the fifth embodiment, the current block is divided in proportion to the size of the current block. The current block 2100 may be horizontally divided into M / 4: M / 4: M / 2 and vertically divided into N / 4: N / 4: N / 2. Accordingly, the current block 2100 includes four blocks 2102, 2104, 2106 and 2108 of size M / 4 X N / 4, two blocks 2110 and 2112 of size M / 2 X N / 4, Two blocks 2114 and 2116, and one block 2118 of size M / 2 X N / 2.

As in the first embodiment, the first zone of the current block 2100 may be set to include only the block 2102 as a sub-zone. And the second zone of the current block 2100 may be set to include three blocks 2104, 2106, 2108 of size 4X4 as sub-zones. The third zone of the current block 2100 may be set to include the remaining blocks 2110, 2112, 2114, 2116, and 2118 having a low probability that the effective transform coefficient is distributed as a subarea.

In the fifth embodiment, the division ratio of the current block 2000 is set to 1: 1: 2, but it may be set to another division ratio according to the embodiment. The division ratio may be a predetermined value or may be specified in a slice header, a picture parameter set (PPS), and a sequence parameter set (SPS).

22-24 illustrate an embodiment of dividing the current block into zones and sub-zones, depending on the size of the current block.

FIG. 22 illustrates a method of dividing the current block 2200 of Mx8 size according to the dividing method of the fourth embodiment of FIG. The current block 2200 may be divided horizontally into sizes 4, 4, and M-8. However, since the height of the current block 2200 is not greater than 8, the current block 2200 is vertically divided into size 4 and 4.

The first zone and the second zone are determined similarly to the fourth embodiment in Fig. However, the third zone may include only two blocks 2210 and 2212 whose size is (M-8) X4 as a sub-zone. Similarly, when the current block size is 8xN, the first zone and the second zone are determined as in the fourth embodiment of Fig. 20, and the third zone is determined as 2 < Only blocks may be included. If the size of the current block 2200 is 8x8, only the first zone including one sub-zone and the second zone including three sub-zones are set.

23 illustrates a method of dividing the current block 2300 of Mx4 size according to the dividing method of the fourth embodiment of Fig. The current block 2300 may be horizontally divided into 4, 4, and M-8. However, if the height of the current block 2300 is not greater than 4, the current block 2300 is not vertically divided.

The first zone is determined similarly to the fourth embodiment in Fig. However, the second zone may only include a block 2302 of size 4x4 as a sub-zone. And the third zone may include only a block 2304 whose size is (M-8) X4 as a sub-zone. Similarly, if the size of the current block is 4xN, the first zone and the second zone may each contain a block of size 4x4 as a sub-zone. And the third zone is a sub-zone and may include blocks of size 4 (N-8) in size. If the size of the current block 2300 is 4x8 or 8x4, only the first zone including one sub-zone and the second zone including one sub-zone are set. When the size of the current block 2300 is 4x4, only the first zone including one sub-zone is set.

FIG. 24 illustrates a method of dividing the current block 2400 of size Mx2 according to the dividing method of the fourth embodiment of FIG. The current block 2400 may be divided horizontally into sizes 4, 4, and M-8. However, if the height of the current block 2400 is not greater than 4, the current block 2400 is not vertically divided.

Since the current block 2400 has a height of 2, the sub-region divided from the current block 2400 has a size of 4x2 or (M-8) x2. The first zone and the second zone each include a block 2402 and a block 2404 that are 4x2 in size as a subarea. And the third zone includes a block 2406 that is (M-8) x2 into sub-zones. Similarly, if the size of the current block is 2xN, the first zone and the second zone may each contain a block of size 2x4 as a sub-zone. And the third zone may include a block of size 2X (N-8) as a sub-zone. If the size of the current block 2400 is 2x8 or 8x2, only the first zone including one sub-zone and the second zone including one sub-zone are set. If the size of the current block 2400 is 2x4 or 4x2, only the first zone including one subarea is set.

As in the case of the fourth embodiment of FIG. 20, when the size of a specific sub-zone is fixed, the number of sub-zones included in the zone may be determined according to the size of the current block, as in FIGS. In Figures 22-24, the size of a particular subarea with a fixed size is not limited to 4x4.

25 is a flowchart illustrating an entropy decoding process based on a last position-based coefficient coding scheme according to an embodiment of the present invention.

In step 2510, the last position information is decoded. The last position information indicates the position where the last effective transform coefficient exists. For example, the last position information may indicate the location where the last effective transform coefficient of the encoding unit or the transform unit exists.

The last position information can directly indicate the position of the last effective transform coefficient. If the last valid conversion factor is located at (lastX, lastY), then the last position information may represent lastX and lastY sequentially. According to an embodiment, the last position information may represent the last effective transform coefficient as an inverse position. Therefore, according to the embodiment, the last position information may be (M-1-lastX, lastY), (lastX, N-1-lastY) and (M-1-lastX, N-1-lastY). The method of parsing the last location information may be determined based on the zone index, the zone flag, the sub-zone index, or the sub-zone flag.

The last position information may indicate the Y coordinate value of the position of the last effective conversion coefficient before the X coordinate value. For example, lastX and lastY may be swapped if the scan order is vertical.

The context for decoding the last position information includes at least one of a zone index, a zone flag, a sub zone index, a sub zone flag, a current block size, a conversion unit size, a coding unit size, a setting direction of last position information, (E.g., intra / inter encoding unit), a component type (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode)

In step 2520, the validity flag (Significant Flag) is decoded. The validity flag indicates whether the conversion coefficient of the pixel is an effective conversion coefficient whose absolute value is larger than zero. The validity flag of the last validity factor may not be decoded. And the final effective transform coefficient is determined to be greater than zero. The validity flags of the transform coefficients scanned after the last effective transform coefficient may not be decoded. And the absolute value of the transform coefficient scanned after the last effective transform coefficient is determined to be zero.

The context for decrypting the validity flag includes the location of the current block, the encoded peripheral validity flag, the zone index, the zone flag, the subregion index, the subregion flag, the current block size, the translation unit size, the encoding unit size, The type of the coefficient coding scheme, the type of the component (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode), and the like.

In step 2530, the first threshold value flag GT1 flag is decoded. The first threshold value flag is decoded with respect to the effective conversion coefficient. Therefore, when the absolute value of the transform coefficient is 0, the first threshold value flag for the transform coefficient is not decoded. The first threshold value flag indicates whether the absolute value of the transform coefficient is greater than one. If the first threshold flag indicates that the absolute value of the transform coefficient is not greater than one, the absolute value of the transform coefficient is determined to be one. If the first threshold flag indicates that the absolute value of the transform coefficient is greater than one, then the absolute value of the transform coefficient is determined to be greater than one.

According to the embodiment, the number of the first threshold value flags may be limited to a predetermined number. For example, when the maximum number of the first threshold flags acquired for the current block is 8, only the first threshold flag is obtained for the eight effective transform coefficients that are decoded first in the scan order. However, the first threshold value flag is not obtained for the ninth and subsequent effective transform coefficients.

The context for decrypting the first threshold value flag includes a number of 1 trailed in the reverse scan order, a number of first threshold value flags in the peripheral sub-zone, a number of peripheral validity flags, a number of peripheral valid first threshold value flags (E.g., an intra / inter coding unit, a coding unit size, a coding unit size, a setting direction of last position information, a conversion skip state, a coding block type , Type of coefficient coding scheme, component type (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode), and the like.

In step 2540, a second threshold value flag (GT2 flag) is decoded. A second threshold value flag is obtained for an effective transform coefficient whose absolute value is greater than one. Therefore, if the absolute value of the transform coefficient is not greater than 1, the second threshold value flag for the transform coefficient is not obtained. The second threshold value flag indicates whether the absolute value of the transform coefficient is greater than two. If the second threshold flag indicates that the absolute value of the transform coefficient is not greater than 2, the absolute value of the transform coefficient is determined to be 2. If the second threshold flag indicates that the absolute value of the transform coefficient is greater than 2, then the absolute value of the transform coefficient is determined to be greater than two.

According to the embodiment, the number of the second threshold value flags may be limited to a predetermined number. For example, when the maximum number of second threshold flags acquired for the current block is 8, only the second threshold flag is set for the effective transform coefficients whose eight absolute values decoded first in the scan order are larger than 1 . However, the second threshold value flag is not obtained for the ninth and subsequent effective transform coefficients.

The context for decoding the second threshold value flag includes the number of the peripheral validity flags in the backward scan order, the number of the valid first threshold value flags, the number of the first threshold value flags in the neighboring sub-zone, the zone index, (E.g., intra / inter coding unit), the type of coefficient coding scheme, the type of coefficient coding scheme, and the type of coefficient coding scheme. Component type (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode), and the like.

In step 2550, the absolute value information is decoded. The absolute value information represents the absolute value of the transform coefficient. If the first threshold flag and the second threshold flag are obtained for the transform coefficient and the second threshold flag indicates that the absolute value of the transform coefficient is greater than 2, Is determined as the absolute value of the conversion coefficient. If only the first threshold flag is obtained without signaling the second threshold flag for the transform coefficient and the first threshold flag indicates that the absolute value of the transform coefficient is greater than 1, The larger value is determined as the absolute value of the conversion factor.

In step 2560, sign information is decoded. The sign information indicates the sign of the effective conversion coefficient. Thus, if the validity flag indicates that the absolute value of the transform coefficient is greater than zero, sign information can be obtained. The code information can be coded by a fixed length coding scheme of 1 bit length.

The encoding according to the last position-based coefficient coding scheme described in FIG. 25 is performed by coding the last position information, the validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, and the sign information described in steps 2510 to 2560 For example, according to the value of the transform coefficient.

26 is a flowchart illustrating a process of entropy decoding based on a full position-based coefficient coding scheme according to an embodiment of the present invention. In the last position-based coefficient coding scheme of FIG. 25, the validity of the transform coefficient is determined without obtaining a validity flag for the last effective transform coefficient and the transform coefficient scanned after the last effective transform coefficient.

However, unlike the last position-based coefficient coding scheme of Fig. 25, the transform coefficients are decoded without the last position flag in the entire position-based coefficient coding scheme. Therefore, the overall location-based coefficient coding scheme of FIG. 26 differs from the last location based coefficient coding scheme of FIG. 25 in that a validity flag is obtained for all transform coefficients. Except for the difference, steps 2610 to 2650 may be set substantially equal to steps 2520 to 2560 of FIG.

FIG. 27 is a flowchart illustrating a process of entropy decoding based on a scan region-based coefficient coding scheme according to an embodiment of the present invention.

In step 2710, the scan area information may be decoded. The scan area indicates an area where the conversion coefficient is scanned in the current block. In the scan area-based coefficient coding scheme, only the transform coefficients in the scan area are scanned, and the transform coefficients outside the scan area are determined as zero.

The scan area information may include coordinate information set with reference to the upper left corner of the current block. For example, when the coordinate information indicates (srX, srY), the scan area is a rectangle determined by four pixels of (0,0), (srX, 0), (0, srY) Area.

The scan area information may include inverse position coordinate information set with reference to the lower right end of the current block. For example, when the current block size is MxN and the coordinates of the lower right pixel of the scan area are (srX, srY), the inverse position coordinate information is (M-1-srX, srY) -SrY) or (M-1-srX, N-1-srY).

The context for decoding the information of the scan area includes a zone index, a zone flag, a sub zone index, a sub zone flag, a current block size, a conversion unit size, a coding unit size, forward or reverse direction, , Intra / inter encoding unit), component type (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode)

In step 2720, the E1 flag may be decoded. The E1 flag is a flag indicating whether the absolute value of all the effective conversion coefficients of the current block is 1 or not. In the scan area-based coefficient coding scheme, the E1 flag may indicate whether the absolute value of all effective conversion coefficients in the scan area is 1 or not.

Depending on the embodiment, decryption of the E1 flag may be omitted. If the E1 flag is omitted, the absolute value of all the effective conversion coefficients in the scan area is not necessarily set to 1.

 The conditions for transmitting the E1 flag can be determined based on the zone index, the zone flag, the sub zone index, the sub zone flag, the number of the first threshold flag in the first encoded zone, and the like. The context for decrypting the E1 flag includes a zone index, a zone flag, a sub-zone index, a sub-zone flag, the number of first threshold flags in a first encoded sub-zone, a current block size, a conversion unit size, (For example, partition mode, prediction), prediction type information (e.g., prediction mode, prediction mode, etc.) Mode), and the like.

In step 2730, the validity flag may be decoded. The validity flag decryption method of step 2730 is the same as step 2610 of Fig.

In step 2740, it is determined whether the E1 flag indicates whether the absolute value of all the effective conversion coefficients of the current block is 1 or not. When the E1 flag indicates 1, the absolute value of all the effective conversion coefficients of the current block is determined as 1. [ And step 2780 is performed to determine the sign of the transform coefficient. Conversely, when the E1 flag indicates 0, the absolute value of the transform coefficient is determined in steps 2750 to 2770. [

In steps 2750 to 2770, the first threshold flag, the second threshold flag, and the absolute value information may be decoded. The decoding method of the first threshold value flag, the second threshold value flag, and the absolute value information of the steps 2750 to 2770 can be set substantially the same as the steps 2620 to 2640 of Fig. After the absolute value of the transform coefficient is determined in accordance with steps 2750 to 2770, step 2780 is performed.

In step 2780, the sign information can be decoded. The code information decoding method of step 2780 can be set substantially equal to step 2650 of FIG.

FIG. 28 is a flowchart illustrating a process of entropy decoding based on a significant group-based coefficient coding according to an embodiment of the present invention.

In step 2810, the valid group flag (SigCGflag) is decoded. The current block may comprise a plurality of coefficient groups. According to one embodiment, the coefficient group may comprise transform coefficients included in blocks of any size. For example, the coefficient group may include transform coefficients included in a 4x4 block. If the current block size is 8x8, the current block can have four coefficient groups.

According to another embodiment, the coefficient group may comprise a predetermined number of successive transform coefficients in the scan order. For example, the coefficient group may include eight consecutive transform coefficients according to the scan order. If the number of transform coefficients included in the current block is 64, the current block may have 8 coefficient groups divided according to the scan order.

The effective group flag is a flag indicating whether or not the coefficient group includes the effective conversion coefficient. Therefore, when the effective group flag is 1, it is determined that the effective conversion coefficient is included in the coefficient group. Conversely, when the valid group flag is 0, it is determined that the effective conversion coefficient is not included in the coefficient group. Therefore, all the transform coefficients of the coefficient group are determined to be zero.

In step 2820, it is determined whether the valid group flag is 1 or not. When the effective group flag is 1, the value of the transform coefficient included in the coefficient group is determined according to the validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, and the sign information obtained in steps 2830 to 2870 . Steps 2830 to 2870 can be set substantially equal to steps 2610 to 2650 of Fig.

29 is a flowchart illustrating an entropy decoding process based on a last position and a group-based coefficient coding according to an embodiment of the present invention.

In step 2910, the last position information is decoded. Step 2910 of FIG. 29 may be set substantially the same as step 2510 of FIG.

In step 2920, the valid group flag (SigCGflag) is decoded. Unlike step 2810 of FIG. 28, in step 2920 of FIG. 29, the valid group flag is not decoded for the coefficient group determined to contain the last valid conversion coefficient according to the last position information. Also, the effective group flag is not decoded for the coefficient group to be decoded after the coefficient group including the last effective conversion coefficient according to the scan order.

In step 2930, it is determined whether the valid group flag is 1 or not. Similar to step 2820 of FIG. 28, when the effective group flag is 1, the coefficient group is added to the coefficient group in accordance with the validity flag, the first threshold value flag, the second threshold value flag, the absolute value information and the sign information obtained in steps 2940 to 2980 The value of the included transform coefficients can be determined. Steps 2940 to 2980 may be set substantially the same as steps 2610 to 2650 of Fig. If the effective group flag is 0, the conversion coefficients of the coefficient group are all determined to be zero.

The coefficient group including the last valid conversion coefficient according to the last position information is a flag indicating whether or not the validity flag, the first threshold flag, the second threshold flag, the absolute value obtained in steps 2940 to 2980, The value of the transform coefficient included in the coefficient group may be determined according to the value information and the code information. The conversion coefficient of the coefficient group to be decoded after the coefficient group including the last effective conversion coefficient according to the scanning order is all determined to be 0 as in the case where the effective group flag is 0. [

FIG. 30 is a flowchart illustrating a process of entropy decoding based on valid group and last position-based coefficient coding according to an embodiment of the present invention.

In step 3010, the valid group flag is decoded. Step 3010 of FIG. 30 may be set substantially the same as step 2810 of FIG.

In step 3020, it is determined whether the valid group flag is 1 or not. When the effective group flag is 0, the conversion coefficients of the coefficient group are all determined to be zero. If the valid group flag is 1, steps 3030 to 3080 are performed.

In steps 3030 to 3080, the last position information, the validity flag, the first threshold flag, the second threshold flag, the absolute value information, and the code information are obtained. The last position information in FIG. 30 shows the position of the last effective transformation coefficient in the coefficient group, unlike the last position information in FIG. The validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, and the sign information of FIG. 30 correspond to the validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, Substantially the same. The transform coefficients of the current block are decoded according to the last position information, the validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, and the sign information obtained in steps 3030 to 3080.

31 is a block diagram of an effective group < RTI ID = 0.0 > and / lastRun  Based coefficient coding scheme (Significant group & last run-based coefficient coding).

In step 3110, the valid group flag is decoded. Step 3110 of FIG. 31 may be set substantially the same as step 2810 of FIG.

In step 3120, it is determined whether the valid group flag is 1 or not. When the effective group flag is 0, the conversion coefficients of the coefficient group are all determined to be zero. If the valid group flag is 1, steps 3130 to 3180 are performed.

If the valid block flag is 1, the lastRun information is decoded in step 3030. The lastRun information indicates the order in which the last validation factor is scanned. For example, if the coefficient group contains 16 transform coefficients and the last effective transform coefficient is scanned at the tenth, the lastRun information may represent 10.

In step 3130, the last valid conversion factor may be determined according to the lastRun information. Like the last position information, the validity flag is not obtained for the last valid conversion coefficient according to the lastRun information. Also, no validity flag is obtained for the transform coefficients scanned after the last valid transform coefficient according to the lastRun information, and the transform coefficients are determined to be zero.

The scan order applied to the parsing of the lastRun information may be determined based on the zone index, zone flag, sub-zone index, sub-zone flag, and the like. For example, the context for encoding lastRun may include a region index, a zone flag, a subspace index, a subspace flag, a current block size, a conversion unit size, a coding unit size, whether forward or backward, (E.g., intra / inter encoding unit), a component type (e.g., luma / chroma), prediction information (e.g., partition mode, prediction mode)

In steps 3140 to 3180, a validity flag, a first threshold value flag, a second threshold value flag, absolute value information, and sign information are obtained. The validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, and the sign information of FIG. 31 correspond to the validity flag, the first threshold value flag, the second threshold value flag, Substantially the same. The transform coefficients of the current block are decoded according to the lastRun information, the validity flag, the first threshold value flag, the second threshold value flag, the absolute value information, and the sign information obtained in steps 3140 to 3180.

32 is a view for explaining a process of entropy decoding based on a first run-level-based coefficient coding according to an embodiment of the present invention.

In step 3210, run information is decoded. The run information indicates the number of transform coefficients having a value 0 between the previous effective transform coefficient and the next effective transform coefficient according to the scan order. For example, if there are three conversion coefficients with a value of 0 between the previous effective conversion coefficient and the next effective conversion coefficient, the run information is 3. If there is no transform coefficient with a value of 0 between the previous effective transform coefficient and the next effective transform coefficient, the run information is determined to be zero.

And the run information obtained from the beginning of the current block may indicate the number of transform coefficients having a value of 0 between the start point and the next effective transform coefficient.

The run information can be decoded into a truncated unary code according to a predetermined number of context models. Then, the run information can be decoded by an exponential-golomb code according to bypass coding. Or run information may be decoded using the two schemes selectively.

The context for decoding the run information includes a position of the current block, a value of the previous effective transform coefficient, a zone index, a zone flag, a sub zone index, a sub zone flag, a size of a current block, a conversion unit size, (E.g., partition mode, prediction mode), and the like, depending on the type of the block to be coded, the type of the block to be coded, the type of the coded block (e.g., intra /

In step 3220, level information is decoded. The level information indicates the absolute value of the effective conversion coefficient that comes after the conversion coefficient whose value is determined according to the run information. For example, when the value of the effective conversion coefficient is -2, the level information indicates 2.

The level information may be decoded into a truncated unary code according to a predetermined number of context models. The level information may be decoded by an exponential-golomb code according to bypass coding. Or level information may be decoded using the above two schemes selectively.

The context for decoding the level information includes at least one of the position of the current block, the value of the previous effective transform coefficient, the zone index, the zone flag, the sub zone index, the sub zone flag, the size of the current block, (E.g., partition mode, prediction mode), and the like, depending on the type of the block to be coded, the type of the block to be coded, the type of the coded block (e.g., intra /

In step 3230, the sign information is decoded. The sign information of step 3230 may be set the same as the sign information of step 2560 of FIG. The effective conversion coefficient is decoded in accordance with the level information of step 3220 and the sign information of step 3230. [

In step 3240, the last valid coefficient flag (lastflag) is decoded. The last valid coefficient flag indicates whether the currently determined effective conversion coefficient is the last valid conversion coefficient of the current block. If the effective transform coefficient is the last transform coefficient of the current block, the effective coefficient is not obtained and the effective transform coefficient is determined as the last effective transform coefficient. When the last effective coefficient flag indicates 1, the effective conversion coefficient is determined as the last effective conversion coefficient. Conversely, when the last valid coefficient flag indicates 0, the valid coefficient is not determined as the last valid coefficient

In step 3250, it is determined whether the last valid coefficient flag is 1 or not. If the last coefficient of validity flag is 1, the values of the transform coefficients after the currently determined effective coefficient are all determined to be zero. However, when the last valid coefficient flag is 0, steps 3210 to 3240 are performed again.

Hereinafter, an example of encoding according to the first run-level-based coefficient coding scheme will be described. If the 16 transform coefficients included in the 4x4 current block are 4, 3, 0, -1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, (4), (3), (0, -1), (0,0,1), (0,0,0,1), (0,0,0,0) , 0, 0). The run information for the group 4 is set to 0, the level information is set to 4, the sign information is set to 0 (+), and the last valid coefficient flag is set to 0. The run information for the group (3) is determined as 0, the level information as 3, the sign information as 0 (+), and the last valid coefficient flag as 0. The run information for the group (0, -1) is determined as 1, the level information as 1, the sign information as 1 (-), and the last valid coefficient flag as 0. The run information for the group (0, 0, 1) is determined as 2, the level information as 1, the sign information as 0 (+), and the last valid coefficient flag as 0. The run information for the group (0, 0, 0, 1) is determined as 3, the level information as 1, the sign information as 0 (+) and the last valid coefficient flag as 1. Since the last valid coefficient indicates 1, the information on the group (0, 0, 0, 0, 0) is not additionally generated and the encoding of the current block is terminated.

33 is a view for explaining a process of entropy decoding based on a second run-level-based coefficient coding scheme according to an embodiment of the present invention.

The second run-level based coefficient coding scheme is different from the first run-level based coefficient coding scheme The last valid coefficient flag is not obtained. In some cases, the second run-level based coefficient coding scheme may provide a higher coding efficiency than the first run-level based coefficient coding scheme by not generating the last significant coefficient flag.

In step 3310, the run information is decoded. The run information in Fig. 33 can be set substantially equal to the run information in Fig.

In step 3320, whether the current transform coefficient is the last transform coefficient of the current block (condition A) is determined. In step 3320, the current transform coefficient indicates the last transform coefficient among the transform coefficients whose value is determined according to the run information. If the current transform coefficient is the last transform coefficient of the current block, the decoding of the current block is terminated. However, if the current transform coefficient is not the last transform coefficient of the current block, then step 3330 is performed.

In step 3330, the level information is decoded. The level information in Fig. 33 can be set substantially equal to the level information in Fig.

In step 3340, the sign information is decoded. The code information in Fig. 33 can be set substantially equal to the code information in Fig.

In step 3350, whether the current transform coefficient is the last transform coefficient of the current block (condition B) is determined. In step 3350, the current transform coefficient indicates an effective transform coefficient determined according to the level information and the sign information. If the current transform coefficient is the last transform coefficient of the current block, the decoding of the current block is terminated. However, if the current transform coefficient is not the last transform coefficient of the current block, then step 3310 is performed.

Hereinafter, an example of encoding according to the second run-level-based coefficient coding scheme will be described. If the 16 transform coefficients included in the 4x4 current block are 4, 3, 0, -1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, (4), (3), (0, -1), (0,0,1), (0,0,0,1), (0,0,0,0) , 0, 0). The run information for the group 4 is determined to be 0, the level information to 4, and the sign information to 0 (+). The run information for group 3 is determined to be 0, the level information to 3, and the sign information to 0 (+). The run information for the group (0, -1) is determined as 1, the level information as 1, and the sign information as 1 (-). The run information for the group (0, 0, 1) is determined as 2, the level information as 1, and the sign information as 0 (+). The run information for the group (0, 0, 0, 1) is determined as 3, the level information as 1, and the sign information as 0 (+). Only run information having a value of 5 for the group (0, 0, 0, 0, 0) is generated and the encoding of the current block is terminated.

34 and 35 are diagrams for explaining an embodiment for setting a scan area.

The scan area indicates an area where the conversion coefficient is scanned in the current block. In the scan area-based coefficient coding scheme, only the transform coefficients in the scan area are scanned, and the transform coefficients outside the scan area are determined as zero.

The entropy decoding unit 1620 can scan the current block in various ways. In one embodiment, the scan area may be equal to the size of the current block. Or the coordinates indicated by the scan area information, the entropy decoding unit 1620 can determine a part of the current block as a scan area.

FIG. 34 shows a method of determining a scan area in the form of a rectangle according to an embodiment.

In Fig. 34, a rectangular scan area 3401 is shown. The scan area 3401 can be defined as (srX, srY) which is the coordinate of the lower right side sample of the scan area. srX is determined by the x-coordinate component of the location of the rightmost significant transform coefficient, and srY is determined by the y-coordinate component of the location of the lowest valid transform coefficient. The scan area 3401 is determined according to four pixels of (0,0), (srX, 0), (0, srY), (srX, srY).

The scan area information may include coordinate information set with reference to the upper left corner of the current block. For example, when the coordinate information indicates (srX, srY), the scan area is a rectangle determined by four pixels of (0,0), (srX, 0), (0, srY) Area.

The scan area information may include inverse position coordinate information set with reference to the lower right end of the current block. For example, when the current block size is MxN and the coordinates of the lower right pixel of the scan area are (srX, srY), the inverse position coordinate information is (M-1-srX, srY) -SrY) or (M-1-srX, N-1-srY).

FIG. 35 shows a method of determining a scan area in the form of a square according to an embodiment.

FIG. 35 shows a scan area 3501 in the form of a square. The scan area 3501 may be defined as srR, which is the size of the side of the scan area. srR is determined by a larger value among the x-coordinate component of the position of the rightmost effective transformation coefficient and the y-coordinate component of the position of the lowest effective transformation coefficient. Therefore, the scan area 3501 is determined according to four pixels of (0,0), (srR, 0), (0, srR), (srR, srR).

The scan area information in Fig. 35 shows only the length of the sides of the scan area that is a square. Since only the SRR is included in the scan area information in Fig. 35, the data size is smaller than the scan area information in Fig. 34 including two values. Therefore, when the scan area is set to a square as shown in FIG. 35, the encoding efficiency may increase in some cases.

Figure 36 shows the current block divided into nine sub-zones. Referring to Fig. 36, a method of determining the scan order of the current block and a method of determining the context of the zone flag, sub zone flag, run information, level information, and last valid coefficient flag of the current block will be described.

Fig. 36 shows an embodiment in which the scan direction of the current block is a vertical direction or a horizontal direction. The scan direction of the current block may be determined by a vertical direction, a horizontal direction, a zigzag direction, and a diagonal direction. The scan direction of the sub-zone included in the current block can be independently determined. The scan direction may be determined based on various information. For example, the number of sub-zones including the zone index, the zone flag, the sub-zone index, the sub-zone flag, the surrounding effective coefficient, the intra mode, the size of the CCU, The scanning direction can be determined according to a unit size, a conversion skip state, an encoded block type (e.g., intra / inter coding unit), a component type (e.g., luma / chroma), prediction information .

36 shows a current block including three zones and nine sub-zones. The current block may be a conversion unit, an encoding unit, or another block unit.

The first zone z0 comprises a first sub-zone sz0, the second zone z1 comprises second through fourth sub-zones sz1, sz2 and sz3, the third zone z2 comprises And the fifth to ninth sub zones sz4, sz5, sz6, sz7, sz8. The scan direction of each sub-zone is determined according to the zone flag and sub-zone flag of the zone and sub-zone shown in Fig.

According to one embodiment, the horizontal effective subarea count value cntHor is set to the third subareas sz2, the sixth subareas sz5, the fourth subareas sz3, the seventh subareas sz6, Can be determined as the sum of the values indicated by the zone flags of the zone sz7 and the ninth sub zone sz8. Then, the vertical effective subarea count value cntVer is set to the second subareas sz1, the fifth subareas sz4, the fourth subareas sz3, the seventh subareas sz6, the eighth subareas sz7 ) And the zone flags of the ninth subareas sz8. The horizontal effective subarea count value (cntHor) and the vertical effective subarea count value (cntVer) are expressed by the following equations.

cntHor = fsz2 + fsz5 + fsz3 + fsz6 + fsz7 + fsz8

cntVer = fsz1 + fsz4 + fsz3 + fsz6 + fsz7 + fsz8)

Then, a first horizontal constant isHor4, a first vertical constant isVer4, a second horizontal constant isHor8, and a second horizontal constant isHor4 according to the sub-zone flag, the horizontal effective subarea count value cntHor and the vertical effective subarea count value cntVer, , A second vertical constant (isVer8) is determined. The scan direction of the current block may be determined according to the first horizontal constant isHor4, the first vertical constant isVer4, the second horizontal constant isHor8, and the second vertical constant isVer8.

The first horizontal constant isHor4 is set such that the first subzone sz0 is the effective subzone and the second subzone sz1 or the fifth subzone sz4 is the effective subzone and the horizontal effective subarea count value cntHor ) Is 0, it is determined to be 1. If the above condition is not satisfied, the first horizontal constant is determined to be zero.

The first vertical constant isVer4 is set such that the first subzone sz0 is the effective subzone and the third subzone sz2 or the sixth subzone sz5 is the effective subzone and the vertical effective subarea count value cntVer ) Is 0, it is determined to be 1. If the above condition is not satisfied, the first horizontal constant is determined to be zero.

The second horizontal constant isHor8 is determined to be 1 when the first subareas sz0 and the second subareas sz1 are valid subareas and the horizontal effective subarea count value cntHor is zero. If the above condition is not satisfied, the first horizontal constant is determined to be zero.

The second vertical constant isVer8 is determined to be 1 when the first sub zone sz0 and the third sub zone sz2 are valid subareas and the vertical effective subarea count value cntVer is zero. If the above condition is not satisfied, the first horizontal constant is determined to be zero. A method of determining a first horizontal constant isHor4, a first vertical constant isVer4, a second horizontal constant isHor8, and a second vertical constant isVer8 is described below.

isHor4 = fsz0 & (fsz1 || fsz4) & (cntHor == 0)

isVer4 = fsz0 & (fsz2 || fsz5) & (cntVer == 0)

isHor8 = fsz0 & fsz1 & (cntHor == 0)

isVer8 = fsz0 & fsz2 & (cntVer == 0)

According to one embodiment, the temporary scan index tmpScanIdx may be determined according to the prediction mode of the current block. If the prediction mode (Imode) of the current block is close to the vertical mode (VerMode), the temporary scan index tmpScanIdx may indicate a vertical scan (Scan_Ver). It can be determined that the intra-prediction mode (Imode) and the vertical mode (VerMode) of the current block are close to each other when the intra-mode index difference between the intra-prediction mode (Imode) and the vertical mode (VerMode) of the current block is 5 or less.

If the prediction mode (Imode) of the current block is close to the horizontal mode (HorMode), the temporary scan index tmpScanIdx may indicate a horizontal scan (Scan_Hor). It can be determined that the intra-prediction mode (Imode) of the current block and the horizontal mode (HorMode) are close to each other when the intra-mode index difference between the intra-prediction mode (Imode) and the horizontal mode (HorMode) of the current block is 5 or less.

If the intra-prediction mode (Imode) of the current block is not close to the vertical mode (VerMode) or the horizontal mode (HorMode), the temporary scan index tmpScanIdx may indicate a diagonal scan (Scan_Diag). When the current block is inter-predicted, the temporary scan index tmpScanIdx may indicate a scan zigzag. An embodiment concerning a method of determining the temporary scan index (tmpScanIdx) is described by the following equation.

tmpScanIdx = | Imode - VerMode | <5? Scan_Ver: (| Imode - HorMode | <5? Scan_Hor: Scan_Diag)

or tmpScanIdx = Scan_Zigzag

The scan direction ScanIdx of the current block is determined based on the first horizontal constant isHor4, the first vertical constant isVer4, the second horizontal constant isHor8, the second vertical constant isVer8, and the temporary scan index tmpScanIdx, Can be determined. When the first sub zone sz0 is the effective subarea and the last zone effective value is in the first zone z0, the scan direction (ScanIdx) of the current block is determined to be the same as the scan direction indicated by the temporary scan index tmpScanIdx . However, when the first sub zone sz0 is an effective sub zone and there is no last effective coefficient in the first zone Z0, the scan direction of the current block according to the first horizontal constant isHor4 and the first vertical constant isVer4 (ScanIdx) can be determined. For example, when the first horizontal constant isHor4 is 1, the scan direction (ScanIdx) of the current block may be determined as the horizontal direction (Scan_Hor). When the first vertical constant isVer4 is 1, the scan direction (ScanIdx) of the current block may be determined as the vertical direction (Scan_Ver). When the first horizontal constant isHor4 and the first vertical constant isVer4 are both 0, the scan direction (ScanIdx) of the current block may be determined as the zigzag direction (Scan_Zigzag).

When the first sub-zone sz0 is not an effective sub-zone, the second sub-zone sz1 is an effective sub-zone, and the second horizontal constant isHor8 is 1, the scan direction ScanIdx of the current block is horizontal (Scan_Hor). When the first sub-zone sz0 is not an effective sub-zone, the third sub-zone sz2 is an effective sub-zone, and the second vertical constant isVer8 is 1, the scan direction ScanIdx of the current block is vertical Direction (Scan_Ver). If the above condition is not satisfied, the scan direction (ScanIdx) of the current block may be determined as the zigzag direction (Scan_Zigzag).

An embodiment of a method for determining the scan direction (ScanIdx) of the current block is described by the following equation.

If fsz0

ScanIdx = fz0? tmpScanIdx: (isHor4? Scan_Hor: (isVer4? Scan_Ver: Scan_Zigzag))

else

ScanIdx = fsz1 & isHor8? Scan_Hor: (SZ2 & isVer8? Scan_Ver: Scan_Zigzag)

According to the above-described method for determining the scan direction of the current block, the scan direction of the current block can be determined according to the intra prediction mode of the current block. Accordingly, the scan direction of the current block may be a vertical mode, a horizontal mode, and a diagonal mode depending on the prediction direction of the intra prediction mode of the current block.

Also, if only the upper sub-zone of the current block is an effective sub-zone, the scan direction of the current block may be the horizontal mode. Similarly, if only the left sub-zone of the current block is an effective sub-zone, the scan direction of the current block may be the vertical mode.

The scan order determination method described on the basis of FIG. 36 can be applied to the embodiment relating to the division of regions and sub-regions described in FIGS. Hereinafter, a method for determining the context of the zone flag, sub zone flag, run information, level information, and last valid coefficient flag will be described.

According to one embodiment, the entropy decoding unit 1620 may determine the context index indicating the context of the zone flag according to the size of the current block and the zone index. The size index (Log2size) of the current block compares a value (CONV_LOG2 (Max (iwidth, iheight)) - 1) smaller than the value obtained by converting the larger of the height and width of the current block into the binary log value - It is determined to be a small value. The context index of the zone flag may be determined by adding a zone index (izone) to twice the size index (Log2size). The zone index (izone) of the first zone is zero and the zone index (izone) of the second zone is one.

The context index of the zone flag may also be determined according to the components of the current block. For example, when the component of the current block is luma, the context index of the zone flag is not changed. However, when the component of the current block is chroma, the context index of the zone flag increases by the zone flag chroma offset (offset_chroma_zflag). The value of the zone flag chroma offset (offset_chroma_zflag) is set equal to the number of contexts for the luma block. Thus, the context of the zone flag may separately include the context for the luma block and the context for the chroma block.

The following equation represents a method of determining a context index of a zone flag according to the above embodiment.

Log2size = Min (CONV_LOG2 (Max (iWidth, iHeight)) - 1, 5);

ctxIdx = 2 * Log2size + izone

ctxIdx = luma? ctxIdx: ctxIdx + offset_chroma_zflag

Since the range of the size index (Log2size) in the above equation is 0 to 5, the range of the context index of the zone flag for the luma block is 0 to 11 (ctxIdx = 2 * Log2size + izone). The zone flag chroma offset (offset_chroma_zflag) is determined to be 12, such as the number of context indexes of the zone flags for the luma block, and the entire range of context indexes of the zone flags is 0 to 23.

The method of setting the context of the zone flag may be changed according to the minimum size of the current block, the method of setting the zone and the sub zone, and the like.

According to one embodiment, the entropy decoding unit 1620 can determine a context index indicating the context of the sub-zone flag according to the size of the current block, the zone flag, the sub-zone flag, and the sub-zone index. The size index (Log2size) of the current block compares a value (CONV_LOG2 (Max (iwidth, iheight)) - 1) smaller than the value obtained by converting the larger of the height and width of the current block into the binary log value - It is determined to be a small value. The context index of the sub-zone flag may be determined by adding the offset value determined according to the sub-zone index, the sub-zone flag, and the zone flag to 13 times the size index Log2size.

For example, if the current subarea is the second subarea or the third subarea (isz == 1 || isz == 2), the fourth subarea is the effective subarea (szflag [3] Lt; / RTI &gt; can be determined to be 9. Also, the offset may be determined to be 12 when the current sub-zone is the fourth sub-zone (isz == 3) and the current zone includes the last effective conversion factor (zflag [iz]). If the current subarea is the fifth subarea and the seventh subarea is the effective subarea (isz == 4 & szflag [6]), or if the current subarea is the sixth subarea and the eighth subarea is the effective subarea (isz == 5 & szflag [7]), the offset may be determined to be 10. If the current sub-zone is the seventh sub-zone or the eighth sub-zone (isz == 6 || isz == 7) and the ninth sub-zone is the effective sub-zone (szflag [8] Can be determined. If all four conditions described above are not met, the offset may be determined according to the subzone index (iszone) of the current subzone.

Also, the context index of the sub-zone flag may be determined according to the component of the current block. For example, when the component of the current block is luma, the context index of the subarea flag is not changed. However, when the component of the current block is chroma, the context index of the subspace flag is increased by the subspace flag chroma offset (offset_chroma_szflag). The value of the sub-zone flag chroma offset (offset_chroma_szflag) is set equal to the number of contexts for the luma block. Thus, the context of the sub-zone flag may separately include the context for the luma block and the context for the chroma block.

The following expression shows a method of determining a context index of a sub-zone flag according to the embodiment.

Log2size = Min (CONV_LOG2 (Max (iWidth, iHeight)) - 1, 5);

ctxIdx = 13 * Log2size;

ctxIdx = ctxIdx + 9, if (isz == 1 || isz == 2) & szflag [3]

ctxIdx = ctxIdx + 12, elseif (isz == 3) & zflag [iz]

ctxIdx = ctxIdx + 10, elseif (isz == 4 & szflag [6] || isz == 5 & szflag [7]

ctxIdx = ctxIdx + 11, elseif (isz == 6 || isz == 7) & szflag [8]

ctxIdx = ctxIdx + iszone, Else

ctxIdx = luma? ctxIdx: ctxIdx + offset_chroma_szflag

Since the range of the size index (Log2size) is 0 to 5 in the above equation, the range of the context index of the zone flag for the luma block is from 0 to 77 (when Log2size is 5 and the offset value is 12, the maximum value of the context index Is 77). If the sub-zone flag chroma offset (offset_chroma_zflag) is determined to be 78, the number of context indexes of the sub-zone flag for the luma block, the range of the context index of the zone flag is 0 to 155.

The method of setting the context of the sub-zone flag may be changed according to the minimum size of the current block, the method of setting the zone and sub-zone, and the like.

According to one embodiment, the entropy decoding unit 1620 may determine the context index indicating the context of the run information according to the absolute value of the previous effective transform coefficient, the zone index of the current zone, the zone flag, and the current sub-zone.

For example, the context of the run information can be determined to be a multiple of a small value by comparing 5 with a value that is one less than the absolute value of the previous effective transform coefficient. And if there is no last effective transform coefficient in the current zone, the context of the run information can be increased by 12. And if the zone index of the current zone is greater than zero (if the current zone is the second zone (iz == 1) or the third zone (iz == 2)) then the context of the run information may be increased by 24. (False) when the condition index of the current zone is smaller than 2 (iz <2) and the current sub-zone is in the scan order and the middle of the current block (pos <(M * N / 2)) is not satisfied , The context of the run information can be increased by 48.

Also, the context index of the run information can be determined according to the component of the current block. For example, when the component of the current block is luma, the context index of the subarea flag is not changed. However, when the component of the current block is chroma, the context index of the run information can be increased by the run information chroma offset (offset_chroma_run). The value of the run information chroma offset (offset_chroma_run) may be set to one. Accordingly, the context of the run information may separately include the context for the luma block and the context for the chroma block.

The following equation represents a method of determining the context index of run information according to the above embodiment.

ctxIdx = ((Min (prev_level - 1, 5)) * 2

ctxIdx = ctxIdx + 12, if zflag [iz] == 0

ctxIdx = ctxIdx + 24, if trace> 0

ctxIdx = ctxIdx + 48, if iz <2 & pos <(M * N / 2) == false

ctxIdx = luma? ctxIdx: ctxIdx + offset_chroma_run

The method of setting the context of the run information may be changed according to the method of classifying the absolute value of the previous effective transform coefficient, the context classification method according to the region and the sub-region, and the like.

According to one embodiment, the entropy decoding unit 1620 may determine a context index indicating the context of the level information according to the absolute value of the previous effective transform coefficient, the zone index of the current zone and the zone flag, and the current sub-zone location.

For example, the context of the level information may be determined to be a multiple of a small value by comparing 5 with a value that is one less than the absolute value of the previous effective transform coefficient. And if there is no last valid conversion factor in the current zone, the context of the level information can be increased by 12. And if the zone index of the current zone is greater than zero (if the current zone is the second zone (iz == 1) or the third zone (iz == 2)) then the context of the level information may be increased by 24. And the condition that the current subarea is in the scan order and the middle of the current block (pos <(M * N / 2)) is not satisfied (false) while the zone index of the current zone is smaller than 2 (iz < , And if the current block is a luma block, the context of the level information may be increased by 48.

The context index of the level information may be determined according to the component of the current block. For example, when the component of the current block is luma, the context index of the subarea flag is not changed. However, when the component of the current block is chroma, the context index of the level information may be increased by the level information chroma offset (offset_chroma_level). The value of the level information chroma offset (offset_chroma_level) may be set to one. Thus, the context of the level information may separately include the context for the luma block and the context for the chroma block.

The following equation shows a method of determining the context index of the level information according to the embodiment.

ctxIdx = ((Min (prev_level - 1, 5)) * 2

ctxIdx = ctxIdx + 12, if zflag [iz] == 0

ctxIdx = ctxIdx + 24, if trace> 0

ctxIdx = ctxIdx + 48, if luma & (iz <2 & pos <(M * N / 2) == false)

ctxIdx = luma? ctxIdx: ctxIdx + offset_chroma_level

The method of setting the context of the level information may be changed according to the method of classifying the absolute value of the previous effective transform coefficient, the method of classifying the region and the sub-region, and the like.

According to one embodiment, the entropy decoding unit 1620 calculates the context index indicating the context of the last valid coefficient flag according to the absolute value of the current effective transform coefficient, the absolute value of the previous effective transform coefficient, the zone index of the current zone, You can decide.

For example, when the absolute value of the current effective conversion coefficient is greater than 1, the context of the last valid coefficient flag is determined to be zero. When the absolute value of the current effective conversion coefficient is 1 and the absolute value of the absolute value of the previous effective conversion coefficient is greater than 1, the context of the last valid coefficient flag is determined to be 1. [ When the absolute value of the current effective conversion coefficient is 1 and the absolute value of the absolute value of the previous effective conversion coefficient is 1, the context of the last valid coefficient flag is determined to be 2. [

The context of the last significant coefficient flag can be increased by 3 if there is no last valid transform coefficient in the current zone. And if the zone index of the current zone is greater than zero (if the current zone is a second zone (iz == 1) or a third zone (iz == 2), then the context of the last validity factor flag may be increased by 6 . When the current block is a chroma block, the context of the last valid coefficient flag increases by the level information chroma offset (offset_chroma_last). The last effective coefficient flag chroma offset (offset_chroma_last) is set equal to the number of contexts for the luma block. Therefore, the last effective coefficient flag chroma offset (offset_chroma_last) in the above embodiment may be determined to be 12.

The following expression shows a method of determining the context index of the last valid coefficient flag according to the embodiment.

ctxIdx = level> 1? 0: (prev_level> 1? 1: 2)

ctxIdx = ctxIdx + 3, if zflag [iz] == 0

ctxIdx = ctxIdx + 6, if trace> 0

ctxIdx = luma? ctxIdx: ctxIdx + offset_chroma_last

The method of setting the context of the last valid coefficient flag may be changed according to the method of classifying the absolute value of the current effective transform coefficient and the previous effective transform coefficient, the classification method of the region and the sub region, and the like.

FIG. 37 shows a flowchart of a video decoding method 3700 for obtaining a transform coefficient array of a current block based on a plurality of zones and a plurality of sub zones in which the current block is divided.

In step 3710, a bit stream containing the zone flag, sub-zone flag and transform coefficient information of the current block is received. The context of the current block can be determined according to the size of the current block, the zone flag, the index of the zone, the sub zone flag, the sub zone index, and the like.

In step 3720, the current block is divided into a plurality of zones. According to one embodiment, the current block may be divided into a first zone and a second zone having a predetermined zone size irrespective of the size of the current block, and a third zone except for the first zone and the second zone in the current block . Alternatively, the current block may be divided into a first zone and a second zone having a zone size proportional to the size of the current block, and a third zone except for the first zone and the second zone in the current block. The number of zones divided according to the size of the current block can be determined.

In step 3730, in accordance with the zone flags for the plurality of zones of the current block, it is determined which of the plurality of zones the last valid conversion factor of the current block is included in. The zone flag may indicate a first value for the last zone including the sub-zone including the effective transform coefficient among the plurality of zones in which the current block is divided, and may represent the second value for the remaining zones. According to an embodiment, if all the values of the zone flags from the first to the (n-1) th zones of the n number of the plurality of zones indicate the second value, the last effective conversion coefficient of the current block is May be determined to be included. The zone flag can be parsed according to the context of the current block.

In step 3740, a zone in which at least one of the plurality of zones may contain the effective conversion coefficient is divided into a plurality of sub-zones. According to one embodiment, the first zone and the second zone may be divided into a predetermined sub-zone size regardless of the size of the current block, and the third zone may be divided according to the size of the current block. The number of sub-zones to be divided according to the size of the current block can be determined.

In step 3750, it is determined, based on the sub-zone flags for the plurality of sub-zones of the current block, that at least one valid conversion coefficient is included for each of the plurality of sub-zones. The subspace flag may represent a first value for the subspace containing the effective transform coefficients and a second value for the subspace that does not contain the effective transform coefficients. According to one embodiment, when the area including the last valid conversion coefficient of the current block includes m sub-zones, the values of the sub-zone flags from the first to the (m-1) th sub- , It can be determined that the effective transform coefficient is included in the m-th sub-zone. A sub-zone flag may be parsed according to the context of the current block.

Based on the zone flag and the subspace flag in step 3760, the coefficient coding scheme for the subspace containing the effective transform coefficient of at least one of the plurality of subspaces is determined.

According to one embodiment, when the last effective transform coefficient of the current block is not included in the zone including the sub-zone, the coefficient coding scheme for the sub-zone may be determined by the first run-level based coefficient coding scheme. When the last effective transform coefficient of the current block is included in the zone including the sub-zone, the coefficient coding scheme for the sub-zone may be determined by the second run-level based coefficient coding scheme.

According to one embodiment, the coefficient coding scheme for all sub-zones may be determined by a second run-level based coefficient coding scheme.

In step 3770, the transform coefficient information of the current block is obtained by parsing the transform coefficient information of the current block according to the coefficient coding scheme. Depending on the magnitude of one or more transform coefficients restored prior to the current sample, the context of the current sample can be determined. Based on at least one of the index of the zone to which the sub-zone belongs, the index of the sub-zone, the zone flag, the sub-zone flag, the number of sub-zones by topic, the size of the current block, The order can be determined. The transformation coefficient array of the current sub-region included in the current block can be obtained by parsing the transform coefficient information of the current sub-region according to at least one of the context of the current sample, the scan order, and the coefficient coding scheme.

The configurations related to video decoding performed in the video decoding apparatus 1600 of FIG. 16 may be included in the video decoding method 3700 of FIG.

Fig. 38 shows a block diagram of a video encoding apparatus 3800 for encoding an array of transform coefficients of the current block based on a plurality of regions and a plurality of sub-regions in which the current block is divided.

The video encoding apparatus 3800 includes an entropy encoding unit 3810 and a bitstream output unit 3820. 38, the entropy encoding unit 3810 and the bitstream output unit 3820 are represented by separate constituent units. However, according to the embodiment, the entropy encoding unit 3810 and the bitstream output unit 3820 are combined to form a single configuration May be implemented as a unit.

38, the entropy encoding unit 3810 and the bitstream output unit 3820 are represented by a unit located in one apparatus, but the apparatuses responsible for the functions of the entropy encoding unit 3810 and the bitstream output unit 3820 are It is not necessarily physically contiguous. Accordingly, the entropy encoding unit 3810 and the bitstream output unit 3820 may be dispersed according to the embodiment.

The entropy encoding unit 3810 and the bitstream output unit 3820 may be implemented by one processor according to an embodiment. And may be implemented by a plurality of processors according to an embodiment.

The entropy encoding unit 3810 divides the current block into a plurality of regions.

The entropy encoding unit 3810 determines a zone flag for a plurality of zones of the current block according to which zone among the plurality of zones of the current block is included in the last effective transformation coefficient of the current block.

The entropy encoding unit 3810 divides a region into which the effective transformation coefficient of at least one of the plurality of regions can be included, into a plurality of sub-regions.

The entropy encoding unit 3810 determines a subarea flag for a plurality of subareas of the current block according to whether or not at least one validation coefficient is included for each of the plurality of subareas.

The entropy encoding unit 3810 determines a coefficient coding scheme for a subarea that includes at least one of the plurality of subareas, based on the zone flag and the subarea flag.

The entropy encoding unit 3810 determines the transform coefficient information of the current block from the transform coefficient array of the current block according to the coefficient coding scheme.

The bit stream output unit 3820 outputs a bit stream including the zone flag, the sub zone flag, and the transform coefficient information of the current block.

The video coding apparatus 3800 of FIG. 38 can perform a coding function corresponding to the decoding function performed by the video decoding apparatus 1600 of FIG.

FIG. 39 shows a flowchart of a video encoding method 3900 for encoding a transform coefficient array of a current block based on a plurality of zones and a plurality of sub-zones in which the current block is divided.

In step 3910, the current block is divided into a plurality of zones.

In step 3920, the zone flags for the plurality of zones of the current block are determined according to which of the plurality of zones of the current block the last effective transformation coefficient of the current block is included in.

In step 3930, a zone in which at least one of the plurality of zones may contain the effective conversion coefficient is divided into a plurality of sub-zones.

In step 3940, a sub-zone flag for a plurality of sub-zones of the current block is determined, depending on whether at least one valid conversion coefficient is included for each of the plurality of sub-zones.

In step 3950, based on the zone flag and the subspace flag, the coefficient coding scheme for the subspace containing the effective transform coefficient of at least one of the plurality of sub zones is determined.

In step 3960, the transform coefficient information of the current block is determined from the transform coefficient array of the current block according to the coefficient coding scheme.

In step 3970, a bitstream including a zone flag, a sub-zone flag, and transform coefficient information of the current block is output.

The configurations relating to video encoding performed in the video encoding apparatus 3800 of FIG. 38 may be included in the video encoding method 3900 of FIG.

According to a video coding technique based on the coding units of the tree structure described above with reference to FIGS. 1 to 39, video data of a spatial region is encoded for each coding unit of a tree structure, and a video decoding technique based on coding units of a tree structure Decoding is performed for each maximum encoding unit according to the motion vector, and the video data in the spatial domain is reconstructed, and the video and the video, which is a picture sequence, can be reconstructed. The restored video can be played back by the playback apparatus, stored in a storage medium, or transmitted over a network.

Meanwhile, the above-described embodiments of the present disclosure can be implemented in a general-purpose digital computer that can be created as a program that can be executed by a computer and operates the program using a computer-readable recording medium.

While this disclosure has been described in connection with specific best mode embodiments thereof, it will be apparent to those skilled in the art from this disclosure that alternatives, modifications and variations will be apparent to those skilled in the art. That is, the claims shall be construed to include all such alternatives, modifications and modified inventions. It is therefore intended that all matter contained in the description and drawings be interpreted as illustrative and not in a limiting sense.

Claims (17)

Receiving a bitstream including a zone flag, a subspace flag, and transform coefficient information of a current block; Dividing the current block into a plurality of zones; Determining in which of the plurality of zones the last effective transform coefficient of the current block is included according to the zone flag for the plurality of zones of the current block; Dividing a region into which the effective transformation coefficient of at least one of the plurality of regions may be included into a plurality of subzones; Determining whether at least one valid conversion coefficient is included for each of the plurality of sub-zones according to a sub-zone flag for the plurality of sub-zones of the current block; Determining a coefficient coding scheme for a sub-region comprising at least one effective transform coefficient of the plurality of sub-regions based on the zone flag and the sub-zone flag; And And parsing the transform coefficient information of the current block according to the coefficient coding scheme to obtain an array of transform coefficients of the current block. The method according to claim 1, The zone flag, A first value for a last zone including a sub-zone including a valid transform coefficient among a plurality of zones in which a current block is divided, and a second value for the remaining zones, The sub- Wherein the second value is represented by the first value with respect to the sub-zone including the effective transform coefficient and the second value with respect to the sub-zone not including the effective transform coefficient. 3. The method of claim 2, Wherein determining which zone of the plurality of zones includes the last effective transform coefficient of the current block comprises: if all of the n zone flags from the first to the (n-1) th zones indicate the second value, it is determined that the last effective transform coefficient of the current block is included in the nth zone Wherein the video decoding method comprises the steps of: 3. The method of claim 2, Wherein determining if at least one effective transform coefficient is included for each of the plurality of sub- When the area including the last valid conversion coefficient of the current block includes m subareas, if the values of the subarea flags from the first to the (m-1) th subareas represent the second value, m Th &lt; / RTI &gt; sub-zone includes an effective transform coefficient. The method according to claim 1, Wherein determining the coefficient coding scheme for the sub- When the last effective transform coefficient of the current block is not included in the zone including the sub-zone, the coefficient coding scheme of the sub-zone is set as a first run-level based coefficient coding scheme And, Level coefficient coding scheme for the sub-zone when the last effective transform coefficient of the current block is included in the zone including the sub-zone, The first run-level-based coefficient coding scheme may include run information indicating the number of consecutive zero coefficients, level information indicating the absolute value of the coefficient, and code information indicating the sign of the coefficient (Sign Information) The second run-level-based coefficient coding scheme is a last-zero coefficient indicating whether the coefficients of the run information, the level information, the code information, and the current topic are coefficients of the last topic of the sub- coefficient information is used. The method according to claim 1, Wherein determining the coefficient coding scheme for the sub- Wherein the coefficient coding scheme for the sub-zone is determined by a second run-level-based coefficient coding scheme, The second run-level-based coefficient coding scheme may include run information indicating the number of consecutive zero coefficients, level information indicating the absolute value of the coefficient on the topic, sign information indicating the sign of the coefficient, Wherein coefficient information is used as a last topic indicating whether or not the coefficient is the last topic of the zone. The method according to claim 1, Wherein dividing the current block into a plurality of zones comprises: Dividing the current block into a first zone and a second zone having a predetermined zone size irrespective of the size of the current block and a third zone excluding the first zone and the second zone in the current block, Wherein dividing the zone into a plurality of sub- Wherein the first zone and the second zone are divided into a predetermined sub-zone size regardless of the size of the current block, and the third zone is divided according to the size of the current block. The method according to claim 1, Wherein dividing the current block into a plurality of zones comprises: Dividing the current block into a first zone and a second zone having a zone size proportional to the size of the current block and a third zone excluding the first zone and the second zone in the current block, Wherein dividing the zone into a plurality of sub- And dividing the first to third regions according to the size of the current block. The method according to claim 1, Wherein dividing the current block into a plurality of zones comprises: Wherein the number of zones divided according to the size of the current block is determined, Wherein dividing the zone into a plurality of sub- Wherein the number of sub-zones divided according to the size of the zone is determined. The method according to claim 1, Determining a context of the current block according to the size of the current block; And Parsing the zone flag and subspace flag obtained from the bitstream according to the context of the current block. The method according to claim 1, Further comprising the step of determining the context of the current sample according to the magnitude of the one or more transform coefficients restored prior to the current sample, Wherein the obtaining of the transform coefficient array of the current block comprises: Wherein the transform coefficient array of the current sub-region included in the current block is obtained by parsing the transform coefficient information of the current sub-region according to the context of the current sample and the coefficient coding scheme. The method according to claim 1, Based on at least one of an index of a region to which the subarea belongs, an index of the subarea, the zone flag, the subarea flag, a number of subareas by topic, a size of the current block, Further comprising determining a scan order for the sub-zone, Wherein the obtaining of the transform coefficient array of the current block comprises: Wherein the transform coefficient array of the current block is obtained by parsing the transform coefficient information of the current block according to the scan order and the coefficient coding scheme. Receiving a bitstream including a zone flag of the current block, a sub-zone flag, and transform coefficient information, Dividing the current block into a plurality of zones, Determining which of the plurality of zones includes the last valid conversion coefficient of the current block according to the zone flag for the plurality of zones of the current block, Dividing a region into which the effective transformation coefficient of at least one of the plurality of regions may be included into a plurality of sub- Determining whether at least one valid conversion coefficient is included for each of the plurality of sub-zones according to a sub-zone flag for the plurality of sub-zones of the current block, Determining a coefficient coding scheme for a sub-region including at least one effective transform coefficient of the plurality of sub-regions based on the zone flag and the sub-zone flag, And a processor for obtaining transform coefficient arrays of the current block by parsing transform coefficient information of the current block according to the coefficient coding scheme. Dividing the current block into a plurality of zones; Determining a zone flag for a plurality of zones of the current block according to which zone among the plurality of zones of the current block is included in the last effective transformation coefficient of the current block; Dividing a region into which the effective transform coefficients of at least one of the plurality of regions may be included into a plurality of sub-regions; Determining a sub-zone flag for a plurality of sub-zones of the current block, depending on whether at least one valid conversion coefficient is included for each of the plurality of sub-zones; Determining a coefficient coding scheme for a sub-region comprising at least one of the plurality of sub-regions based on the zone flag and the sub-zone flag; Determining transform coefficient information of the current block from a transform coefficient array of the current block according to the coefficient coding scheme; And And outputting a bitstream including the zone flag, the sub-zone flag, and the transform coefficient information of the current block. The current block is divided into a plurality of zones, Determining a zone flag for a plurality of zones of the current block according to whether a last valid conversion coefficient of the current block is included in a zone among a plurality of zones of the current block, Dividing a region into which the effective transformation coefficient of at least one of the plurality of regions may be included into a plurality of sub- Determining a sub-zone flag for a plurality of sub-zones of the current block, depending on whether at least one effective transform coefficient is included for each of the plurality of sub- Determining a coefficient coding scheme for a sub-region including at least one effective transform coefficient of the plurality of sub-regions based on the zone flag and the sub-zone flag, Determining transform coefficient information of the current block from the transform coefficient array of the current block according to the coefficient coding scheme, And a processor for outputting a bit stream including the zone flag, the sub zone flag and the transform coefficient information of the current block. A computer-readable recording medium storing a program for performing the video decoding method of claim 1. A computer-readable recording medium storing a program for performing the video encoding method of claim 14.

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