WO2019117402A1

WO2019117402A1 - Video decoding method and device thereof, and video encoding method and device thereof

Info

Publication number: WO2019117402A1
Application number: PCT/KR2018/003820
Authority: WO
Inventors: 표인지
Original assignee: 삼성전자 주식회사
Priority date: 2017-12-13
Filing date: 2018-03-30
Publication date: 2019-06-20
Also published as: CN116132673A; CN111788830B; KR20200088297A; CN111788830A; CN116132674A

Abstract

Disclosed is a video decoding method for determining a rectangular scan region including all valid transform coefficients in a current block, scanning information related to the transform coefficients in the rectangular scan region according to a predetermined scan order, acquiring transform coefficients of the current block on the basis of the scanned information related to the transform coefficients, generating a residual block of the current block by performing inverse quantization and inverse transformation on the transform coefficients of the current block, and reconstructing the current block on the basis of the generated residual block.

Description

VIDEO DECODING METHOD, DEVICE, AND VIDEO Coding METHOD AND DEVICE

A video decoding method and a video encoding method. And more particularly to entropy decoding and entropy encoding.

Background of the Invention [0002] As the development and dissemination of hardware capable of playing back and storing high-resolution or high-definition video content increases the need for video codecs to effectively encode or decode high-definition or high-definition video content. According to the existing video codec, video is encoded according to a limited encoding method based on a coding unit of a tree structure.

The image data in the spatial domain is transformed into coefficients in the frequency domain using frequency conversion. The video codec divides an image into blocks of a predetermined size for fast calculation of frequency conversion, performs DCT conversion on each block, and encodes frequency coefficients on a block-by-block basis. Compared to image data in the spatial domain, coefficients in the frequency domain have a form that is easy to compress. In particular, since the image pixel values of the spatial domain are expressed by prediction errors through inter prediction or intra prediction of the video codec, many data can be converted to 0 when the frequency transformation is performed on the prediction error. Video codecs reduce the amount of data by replacing consecutively repeated data with small-sized data.

According to various embodiments, entropy decoding efficiency can be increased by determining scan areas based on various factors, scanning information about coefficients, and performing binary arithmetic coding / decoding based on binarization / inverse binarization and context model .

Readable recording medium on which a program for implementing the method according to various embodiments is recorded.

Of course, the technical objects of the various embodiments are not limited to the features mentioned above, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description

The technical objects of the present invention are not limited to the features mentioned above, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description.

The video decoding method according to various embodiments includes: determining a rectangular scan area including all effective transform coefficients in a current block; Scanning information on the transform coefficients in the quadrangular scan area according to a predetermined scan order; And obtaining transform coefficients of the current block based on information about the scanned transform coefficients; Performing inverse quantization and inverse transform on the transform coefficients of the current block to generate a residual block of the current block; And reconstructing a current block based on the generated residual block.

The rectangle scan area includes all effective transform coefficients in the current block, and the remaining area in the current block excluding the square scan area may include only a transform coefficient having a value of 0, which is not an effective transform coefficient.

Wherein the step of determining the rectangular scan area comprises:

Obtaining information on coordinates specifying the quadrangular scan area from a bitstream; And

Determining a quadrangular scan area including all effective transformation coefficients in a current block based on information on coordinates specifying the quadrangular scan area,

The coordinates specifying the quadrangular scan area may indicate a horizontal direction coordinate of the effective transformation coefficient located at the rightmost position in the current block and a vertical direction coordinate of the effective transformation coefficient located at the lowermost position in the current block.

Wherein the step of acquiring information on coordinates specifying the quadrangular scan area from a bitstream comprises:

Performing binary arithmetic decoding based on the context model on information about coordinates specifying the rectangular scan area; And performing inverse binarization on the binary arithmetic decoded information using a predetermined inverse binarization method to obtain inverse binarization information on the coordinates specifying the quadrangular scan area.

The context model may be determined based on at least one of a size of the current block, a color component of the current block, and a bin index.

The predetermined inverse binarization method may be at least one of a fixed length inverse binarization method and a truncated unary inverse binarization method.

The predetermined scan order may be an order according to an inverse zig-zag scan or an order according to an inverse diagonal scan.

The predetermined scan order may be determined based on at least one of a horizontal direction coordinate of the effective transformation coefficient pixel located at the rightmost position in the current block and a vertical direction coordinate of the effective transformation coefficient pixel located at the bottommost position in the current block .

The information on the transform coefficients may be,

A flag information indicating whether an absolute value of the transform coefficient is larger than a predetermined value, remaining level information about an absolute value of the transform coefficient, sign information of the transform coefficient, And binarization parameter information, and the predetermined value may be at least one of 0, 1, and 2.

Wherein obtaining the transform coefficients of the current block based on the information about the scanned transform coefficients comprises:

And performing binary arithmetic decoding and inverse binarization based on the context model on flag information indicating whether the absolute value of the transform coefficients is larger than a predetermined value to obtain transform coefficients of the current block .

Wherein the flag information indicating whether the absolute value of the transform coefficients is larger than a predetermined value includes a first transform coefficient,

Wherein the context model of flag information indicating whether the absolute value of the first transform coefficient is larger than a predetermined value includes information on at least one second transform coefficient previously scanned in accordance with the predetermined scan order, At least one of a position and a color component of the first transformation coefficient, information on the right or lower peripheral transformation coefficient, and a scan position of the first transformation coefficient, a relative position in the scan region of the first transformation coefficient, . &Lt; / RTI >

Wherein the information on the transform coefficients includes flag information indicating whether the absolute value of the transform coefficient is larger than a predetermined value,

The maximum count of the flag information that can be obtained from the bitstream may be determined based on the size of the scan area.

Wherein the scan order of each of the transformation coefficients in the rectangular scan region is determined according to a predetermined scan order, and the step of scanning information on the transformation coefficients in the rectangular scan region according to a predetermined scan order includes: May be scanned according to the scan order of each transform coefficient in the quadrangle scan area.

At least one coefficient group including a predetermined plurality of transform coefficients in the rectangular scan region is determined according to a predetermined forward scan order,

Whether to hide information on the sign of at least one transform coefficient in units of the coefficient group can be determined.

The video decoding apparatus according to various embodiments determines a quadrangular scan region including all the effective transform coefficients in the current block, scans the information about the transform coefficients in the quadrangular scan region according to a predetermined scan order, An entropy decoding unit for obtaining transform coefficients of the current block based on information on coefficients; And an image restoration unit for generating a residual block of the current block by performing inverse quantization and inverse transform on the transform coefficients of the current block and restoring the current block based on the generated residual block.

A video encoding method according to various embodiments includes: obtaining transform coefficients of a current block; Determining a rectangular scan area including all the effective transform coefficients in the current block; Scanning the information on the transform coefficients included in the quadrangular scan area according to a predetermined scan order; Generating entropy-encoded information by entropy encoding based on the information about the scanned transform coefficients; And generating a bitstream including the entropy-encoded information.

According to various embodiments, entropy decoding efficiency can be increased by determining scan areas based on various factors, scanning information about coefficients, and performing binary arithmetic coding / decoding based on binarization / inverse binarization and context model . Particularly, in the process of entropy decoding the information on the transform coefficients, a rectangular scan region including all the effective transform coefficients in the current block is determined, unnecessary scans are reduced by scanning the transform coefficients in the rectangular scan region, The entropy decoding efficiency can be improved by scanning the coefficients adjacent to each other.

FIG. 1A shows a block diagram of a video decoding apparatus according to various embodiments.

1B shows a flow diagram of a video decoding method according to various embodiments.

1C shows a block diagram of a video encoding apparatus according to various embodiments.

Figure 1D shows a flow diagram of a video encoding method according to various embodiments.

FIG. 1E shows a block diagram of an image decoding unit according to various embodiments.

1F shows a block diagram of an image decoding unit according to various embodiments

FIG. 2 is a diagram for explaining a method of scanning intra-block transform coefficients according to an embodiment.

3A is a diagram for explaining a method of scanning an intra-block transform coefficient according to another embodiment.

FIG. 3B is a diagram for explaining an operation of determining intra-block coefficient groups (sub-blocks) and an operation performed for each coefficient group according to another embodiment.

FIG. 4 is a diagram for explaining a process of determining a context model for decoding context-based binary arithmetic decoding information on transform coefficients according to an exemplary embodiment of the present invention.

FIG. 5 is a diagram for explaining a process of determining a context model for decoding context-based binary arithmetic decoding information on transform coefficients according to another embodiment.

FIG. 6A is a diagram for explaining a horizontal priority zigzag scan order for scanning information on intra-block transform coefficients according to an exemplary embodiment.

6B is a diagram for explaining a vertical priority zigzag scan order for scanning information on intra-block transform coefficients according to an embodiment.

FIG. 7A is a diagram for explaining a horizontal scanning order for scanning information on intra-block transform coefficients according to an embodiment.

FIG. 7B is a diagram for explaining a vertical scanning order for scanning information on intra-block transform coefficients according to an embodiment.

8 is a diagram for explaining a diagonal scan order for scanning information on intra-block transform coefficients according to an embodiment.

9A to 9C are diagrams for explaining a residual coding syntax structure according to an embodiment.

9D to 9F are diagrams for explaining a residual coding syntax structure according to another embodiment.

FIG. 10 illustrates a process in which at least one encoding unit is determined by dividing a current encoding unit according to an embodiment.

FIG. 11 illustrates a process in which at least one encoding unit is determined by dividing a non-square encoding unit according to an embodiment.

FIG. 12 illustrates a process in which an encoding unit is divided based on at least one of block type information and division type information according to an embodiment.

FIG. 13 illustrates a method of determining a predetermined encoding unit among odd number of encoding units according to an embodiment.

FIG. 14 shows a sequence in which a plurality of encoding units are processed when a current encoding unit is divided to determine a plurality of encoding units according to an embodiment.

FIG. 15 illustrates a process in which, when an encoding unit can not be processed in a predetermined order according to an embodiment, it is determined that the current encoding unit is divided into odd number of encoding units.

FIG. 16 illustrates a process in which a first encoding unit is divided into at least one encoding unit according to an embodiment of the present invention.

FIG. 17 shows that when the non-square type second coding unit determined by dividing the first coding unit according to an embodiment satisfies a predetermined condition, the form in which the second coding unit can be divided is limited .

FIG. 18 illustrates a process of dividing a square-shaped encoding unit when the division type information can not indicate division into four square-shaped encoding units according to an embodiment

FIG. 19 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.

FIG. 20 illustrates a process of determining the depth of an encoding unit according to a change in type and size of an encoding unit when the encoding unit is recursively divided according to an embodiment to determine a plurality of encoding units.

FIG. 21 illustrates a depth index (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.

22 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. 23 shows 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.

Hereinafter, 'video' may be a still image of a video or a video, that is, a video itself.

Hereinafter, 'sample' means data to be processed as data assigned to a sampling position of an image. For example, pixels in an image in the spatial domain may be samples.

Hereinafter, the 'current block' may refer to a block of an image to be encoded or decoded.

The video decoding apparatus 100 according to various embodiments may include an entropy decoding unit 105 and an image restoring unit 120.

The entropy decoding unit 105 may obtain syntax element information received from the bitstream and entropy-decode the syntax element information. At this time, the syntax element information received from the bitstream may be information on various syntax elements related to the image.

The entropy decoding unit 105 can obtain syntax element information on the current intra-block transformation coefficient from the bitstream and entropy-decode the syntax element information on the current intra-block transformation coefficient. At this time, the current block may be a data unit that can be used in the process of attaching / decrypting an image described with reference to FIG. 10 to FIG.

The entropy decoding unit 105 may obtain information on the current intra-block transform coefficients by scanning the syntax element information about the transform coefficients in the current entropy-decoded block according to a predetermined scan order. The predetermined scan order may be a reverse scan order. Here, the reverse scan order may be a scan order from the pixels on the lower right side in the block to the transform coefficient pixels on the upper left side in the block. The order in which the transform coefficients are scanned in the order of the transform coefficients located on the lower left side from the upper left side transform coefficient pixels can be referred to as the forward scan order and the transform coefficients are scanned from the last transform coefficient located on the lower right side to the order of the upper left side transform coefficients May be referred to as the reverse scan order. The syntax element information on the current intra-block conversion coefficient may be flag information indicating whether the intra-block conversion coefficient is larger than a predetermined value. At this time, the predetermined value may be an integer value equal to or greater than zero. For example, 0, 1 or 2.

The syntax element information regarding the current intra-block transformation coefficient may be syntax element information indicating a remaining level absolute value. The residual level absolute value may mean the difference between the absolute value of the level of the transform coefficient and the absolute value of the base level. The absolute value of the base level may be determined based on the syntax element information indicating that the absolute value of the transform coefficient is larger than a predetermined value. For example, a flag indicating whether the absolute value of the transform coefficient is greater than 0 (or whether the transform coefficient is an effective transform coefficient, where the effective transform coefficient means a transform coefficient whose absolute value of the transform coefficient is larger than 0) Flag (Greater than 1 flag or coeff_abs_level_greater1_flag; hereinafter referred to as GT1 flag) indicating whether or not the value of the flag is greater than 2 and the value of the information (Greater than 0 flag or sig_coeff_flag; hereinafter referred to as GT0 flag) (The Greater than 2 flag or the coeff_abs_level_greater2_flag; referred to as the GT2 flag) may be the absolute value of the base level. Here, when the flag information indicating whether the absolute value of the transform coefficient is larger than the predetermined value is greater than the predetermined value, the value of the flag information may be 1, and if it is smaller than the predetermined value, May be zero. On the other hand, some of the flag information may not be obtained from the bitstream. According to one embodiment, a flag GTn indicating whether the magnitude of the transform coefficient is larger than n (n is an integer), a flag GT (n + 1) indicating whether the magnitude of the transform coefficient is larger than (n + 1) (N + 1), which is a relatively smaller value among the reference values of n, n + 1 and n + 2, when the coefficient GT (n + It is possible to transmit only the flags GTn, GT (n + 1) indicating whether the absolute value of the coefficient is larger and not to include GT (n + 2) in the bitstream.

For example, when the GT0 flag information and the GT1 flag information each indicate that the absolute value of the transform coefficient is greater than 0 and 1, if the GT2 flag is not included in the bitstream, the entropy decoding unit 105 excludes the GT2 flag, The absolute value of the conversion coefficient obtained by subtracting 2 from the absolute value of the conversion coefficient can be determined as the absolute value of the residual level of the conversion coefficient using only the GT0 flag information and the GT1 flag information.

When the GT0 flag information, the GT1 flag information, and the GT2 flag information indicate respectively greater than 0, 1, and 2, the entropy decoding unit 105 determines that the absolute value of the transform coefficient is larger than 2, The absolute value can be determined as the absolute value of the residual level of the transform coefficient. That is, the absolute value of the residual level may indicate an absolute value difference between the absolute value of the effective transform coefficient and a predetermined absolute value determined based on information indicating whether the absolute value of the transform coefficient is larger than a predetermined value.

The entropy decoding unit 105 obtains the syntax element information received from the bitstream, performs binary arithmetic decoding on the syntax element information, performs binary arithmetic decoding, and outputs an empty string bin string can be performed inverse binarization. In this case, the binary arithmetic decoding operation may be performed in the binary arithmetic decoding unit 110, and the inverse binarization operation may be performed in the inverse binarization unit 115. [

The binary arithmetic decoding unit 110 may perform binary arithmetic decoding based on a predetermined context model on the syntax element information obtained from the bitstream. Here, the context model may be information on the probability of occurrence of a bin. The information on the probability of occurrence of the bean includes information (valMPS) indicating one symbol of LPS (Least Propable Symbol), which is a relatively low probability of occurrence of two

symbols

0 and 1, and a Least Probable Symbol (MPS) And information on the probability of occurrence of one symbol. The occurrence probability has a value between 0 and 1. Therefore, if the probability of one of the MPS and the LPS is determined, the information on the probability of occurrence of the other symbol is information on the probability of subtracting the occurrence probability for the predetermined symbol from 1, The binary arithmetic decoding unit 110 can determine the probability of occurrence of the remaining symbols. In this case, the probability of occurrence of one symbol to be determined first may be the probability of occurrence of LPS (Least Probable Symbol). On the other hand, the occurrence probabilities of symbols corresponding to the index values can be determined in advance in the table, and the occurrence probability information for the symbols can be information (pStateIdx) indicating an index indicating occurrence probabilities of symbols determined in the table.

The predetermined context model may be determined based on an index (bin index) indicating the location of the bean, a probability of occurrence of a bean included in a neighboring block of the block including the bean, and various elements of the current block or neighboring blocks.

Alternatively, the binary arithmetic decoding unit 110 may perform binary arithmetic decoding on the syntax element information obtained from the bitstream according to a by-pass mode. At this time, the probability of 0 or 1 for the current binary arithmetic decoding is fixed to 0.5, and binary arithmetic decoding can be performed on the syntax element information based on this probability.

The inverse binarization unit 115 may perform inverse binarization on the bin string, which is an output value generated by performing binary arithmetic decoding. The inverse binarization unit 115 may perform inverse binarization on the bin string based on the inverse binarization method corresponding to the predetermined binarization method. The predetermined binarization method may include a fixed length binarization method, a Rice binarization method, an exponential-Golomb binarization method, and a Golomb-Rice binarization method. Alternatively, the predetermined binarization method may be a binarization method in which the first binarization method and the second binarization method are combined. For example, the inverse binarization unit 115 performs inverse binarization on the first bin string, which is a part of the bin string of the syntax element, based on the inverse binarization method corresponding to the first binarization method, For bin strings, inverse binarization may be performed based on an inverse binarization method corresponding to the second binarization method. The part of the empty string may be a prefix or suffix of the empty string of the syntax element.

Both the binarization method and the inverse binarization method relate to a kind of code word that defines a 1: 1 correspondence of the empty string including at least one bin corresponding to the value of the syntax element. In accordance with one of the various types of binarization methods described above in terms of encoding, an empty string containing at least one bin corresponding to the value of the syntax element is determined, and in accordance with an inverse binarization method in terms of decoding, Can be determined. For example, when the bin string A corresponding to the value a (a is a real number) of the syntax element is determined according to a predetermined binarization / inverse binarization method, the process of determining the bin string A based on the value a of the syntax element is binarized , And the process of determining the value a of the syntax element based on the bin string A can be referred to as an inverse binarization process. However, as described above, the binarization and inverse binarization essentially define the mapping relationship between the value of the syntax element and the bin string, and the person skilled in the art can easily understand that binarization / inverse binarization is substantially the same.

The entropy decoding unit 105 can obtain information on the current intra-block transform coefficients by performing the entropy decoding by scanning the syntax element information about the current intra-block transform coefficient according to a predetermined scan order. The predetermined scan order may be a sequence according to a reverse zigzag scan or a sequence according to a diagonal scan in the reverse direction. However, the present invention is not limited to this, and the predetermined scan order may be various scan orders such as a reverse scan order according to a horizontal scan and a scan order according to a vertical scan. The predetermined scanning order is determined by the horizontal coordinate (for example, x coordinate (x is an integer) in the orthogonal coordinate system) of the effective conversion coefficient pixel located at the rightmost position in the current block and the effective conversion coefficient (E.g., the y coordinate of the Cartesian coordinate system (y is an integer)) values of the pixel. For example, the entropy decoding unit 105 may determine a predetermined scan order based on the size of the horizontal direction coordinate value and the size of the vertical direction coordinate value. The entropy decoding unit 105 can determine the vertical scanning order in the reverse direction in a predetermined scanning order when the horizontal direction coordinate value is larger than the vertical direction coordinate value. The entropy decoding unit 105 may determine a horizontal scanning order in the reverse direction as a predetermined scanning order when the vertical direction coordinate value is larger than the horizontal direction coordinate value.

Alternatively, the entropy decoding unit 105 may determine a vertical first zigzag scan order in a reverse scan direction in a predetermined scan order when the horizontal direction coordinate value is larger than the vertical direction coordinate value. Details of the vertical priority zigzag scan sequence will be described with reference to FIG. 6B. The entropy decoding unit 105 may determine a horizontal first zigzag scan order in a predetermined scanning order if the vertical direction coordinate value is larger than the horizontal direction coordinate value. The details of the horizontal priority zigzag scan sequence will be described with reference to FIG. 6A. The entropy decoding unit 105 may determine one of the reverse direction vertical priority zigzag scanning order and the horizontal priority zigzag scanning order in a predetermined scanning order when the vertical direction coordinate value is equal to the horizontal direction coordinate value.

Alternatively, if the horizontal coordinate value is larger than the vertical coordinate value, the entropy decoding unit 105 may determine a horizontal first zigzag scan order in a predetermined scanning order. On the other hand, if the horizontal direction coordinate value is not larger than the vertical direction coordinate value, the entropy decoding unit 105 may determine a reverse direction vertical first zigzag scan order in a predetermined scan order.

The entropy decoding unit 105 may determine a rectangular scan area including all the effective transform coefficients in the current block before scanning the information on the transform coefficients. In this case, the rectangle scan region includes all the effective transform coefficients in the current block, and the remaining regions in the current block excluding the rectangular scan region may include only the transform coefficients that are 0, not the effective transform coefficients.

The entropy decoding unit 105 can obtain information on the coordinates specifying the quadrangular scan area from the bitstream. The information on the coordinates specifying the rectangular scan area includes information on the horizontal direction coordinate of the effective transformation coefficient located at the rightmost position in the current block and information on the vertical direction coordinate of the effective transformation coefficient located at the lowermost position in the current block . &Lt; / RTI > However, the present invention is not limited to this, and the information about the coordinates specifying the quadrangular scan area may be obtained by multiplying the coordinate value in the horizontal direction with respect to the effective conversion coefficient located at the rightmost position in the current block, And may include only information about a larger one of the direction coordinate values. At this time, the quadrangular scan area is determined by using coordinate values for one direction obtained from the bit stream as a square scan area, and based on the determined horizontal direction coordinate value and vertical direction coordinate value A square scan area can be determined. At this time, the determined horizontal direction coordinate values and vertical direction coordinate values may represent coordinate values of pixels positioned at the lower right corner of the quadrangular scan region. That is, when only the coordinates for one direction are obtained from the bitstream, the entropy decoding unit 105 determines that a square scan region is specified, and based on the obtained coordinate values for one direction, And a square scan area can be determined based on a coordinate value specifying a square scan area.

The entropy decoding unit 105 can determine a rectangular scan area including all the effective transformation coefficients in the current block based on the information on the coordinates specifying the rectangular scan area.

The entropy decoding unit 105 can perform binary arithmetic decoding based on the context model on the information on the coordinates specifying the quadrangular scan area. The entropy decoding unit 105 may perform inverse binarization on the binary arithmetic decoded information based on the inverse binarization method corresponding to the predetermined binarization method to obtain inverse binarization information on the coordinates specifying the quadrangular scan area, Coordinates from which the quadrangular scan area is specified can be obtained from the inverse binarization information regarding the coordinates. At this time, the context model may be determined based on at least one of the size of the current block, the color component of the current block, and the bin index. The color component may include a luminance component and a chrominance component. The empty index may be information indicating the position of the bin that is currently binary arithmetic decoded among the bin strings related to the syntax element. The inverse binarization method corresponding to a predetermined binarization method may be at least one of a fixed length inverse binarization method and a truncated unary inverse binarization method. For example, the entropy decoding unit 105 performs inverse binarization using the fixed length inverse binarization method on the first bin string of the binary arithmetic decoded information to obtain the first inverse binarization information, The second inverse binarization information may be obtained by performing inverse binarization using the cutting type unary inverse inverse binarization method for the second bin string. The entropy decoding unit 105 may obtain coordinates specifying the quadrangular scan area based on the first inverse binarization information and the second inverse binarization information.

The entropy decoding unit 105 performs at least one of binary arithmetic decoding and inverse binarization based on the context model for the transform coefficients based on the information about the valid transform coefficients scanned in the rectangular scan region, Can be obtained.

If the information on the transform coefficients is information indicating whether the absolute value of the current transform coefficient is larger than a predetermined value, and the residual level absolute value information and the sign information of the current transform coefficient, the entropy decoding unit 105 outputs the transform coefficients It is possible to perform binary arithmetic decoding based on the context model. The entropy decoding unit 105 may perform inverse binarization on the information on the binary-arithmetically decoded transform coefficients to obtain a transform coefficient of the current block. The first information on the transform coefficients is information indicating whether the absolute value of the current transform coefficient is larger than a predetermined value and the residual level absolute value information and the sign information of the current transform coefficient, In the case of the binarization parameter information related to the coefficient, the entropy decoding unit 105 may perform binary arithmetic decoding based on the context model with respect to the first information on the transform coefficient.

The entropy decoding unit 105 may perform inverse binarization based on the binary parameter information included in the second information with respect to the first information subjected to the binary arithmetic decoding so as to obtain the transform coefficient of the current block. The binarization parameter information may be Rice Parameter information for the current transform coefficient. The Rice parameter may be information for determining the length of the prefix included in the bin string. Without being limited thereto, the binarization parameter information may be various binarization parameter information for the current transform coefficient.

If the first information on the transform coefficients is the residual level absolute value information of the current transform coefficient, the entropy decoding unit 105 performs a (truncated) Rice binarization method on the residual level absolute value information of the current transform coefficient A value relating to the absolute value of the residual level of the current transform coefficient can be obtained by using the inverse binarization method corresponding to the corresponding inverse binarization method and the exponential Gollum binarization method. For example, the entropy decoding unit 105 performs inverse binarization on the prefix of the bin string of the residual level absolute value information of the current transform coefficient using an inverse binarization method corresponding to the Rice binarization method based on the Rice parameter The first value relating to the absolute value of the residual level of the current transform coefficient is obtained and the inverse binarization using the inverse binarization method corresponding to the exponential smoothed binarization method is performed on the suffix of the bin string of the residual level absolute value information Obtains a second value relating to an absolute value of a residual level of a current transform coefficient, and based on a first value relating to an absolute value of a residual level of the current transform coefficient and a second value relating to an absolute value of a residual level of the current transform coefficient, A value relating to the absolute value of the residual level of the residual level.

The context model for the first transform coefficient among the context models related to the transform coefficients includes information on at least one second transform coefficient previously scanned in accordance with a predetermined scan order, position and color of the first transform coefficient in the current block, Information about the right or lower peripheral transformation coefficient, and the scan position of the first transformation coefficient.

For example, the context model relating to the flag information indicating whether the first conversion coefficient is greater than 0 is based on the number of the right or lower conversion coefficients whose absolute value among the right or lower conversion coefficients of the predetermined position is larger than 0 Can be determined.

The context model for flag information indicating whether the first transform coefficient is greater than 0 is not limited to this, and the absolute value of n (n is a positive integer) transform coefficients previously scanned according to a predetermined scan order is greater than 0 Can be determined based on the number of large effective conversion coefficients.

Alternatively, the context model relating to the flag information indicating whether the first transform coefficient is greater than 0 may be determined based on the position of the first transform coefficient in the coefficient group and the corresponding peripheral right or lower effective coefficient group flags.

Alternatively, the flag information (GT0 flag information) indicating whether the first transform coefficient is greater than 0 may be obtained by adding GT0 flag information of n (n is a positive integer) transform coefficients previously scanned according to a predetermined scan order, The GT0 flag information of the position, color component, and neighboring right or lower n (n is a positive integer) conversion coefficients of the first conversion coefficient, whether the first conversion coefficient on the scan order is the conversion coefficient of the first position in the scan area, And whether or not the first transformation coefficient in the scan order is a transformation coefficient of the final position in the scan area.

The context model relating to the flag information indicating whether the absolute value of the first conversion coefficient is larger than 1 is determined based on the number of the right or lower effective conversion coefficients whose absolute value of the right or lower conversion coefficient of the predetermined position is larger than 1 .

The context model relating to the flag information indicating whether the absolute value of the first transform coefficient is larger than 1 is not limited to the absolute value of n (n is a positive integer) transform coefficients previously scanned according to a predetermined scan order Can be determined based on the number of effective transform coefficients greater than one.

Alternatively, the context model relating to flag information indicating whether the absolute value of the first transform coefficient is greater than 1 may be determined based on GT1 flag information previously decoded in the corresponding coefficient group and GT1 flag information previously decoded in the group.

Alternatively, the flag information (GT1 flag information) indicating whether the absolute value of the first transform coefficient is larger than 1 is obtained by adding GT1 flag information of n (n is a positive integer) transform coefficients previously scanned according to a predetermined scan order, The GT1 flag information of the position, color component, and neighboring right or lower n (n is a positive integer) conversion coefficients of the first transform coefficient in the block, whether the first transform coefficient is the transform coefficient of the first position in the scan area, And whether or not the first transform coefficient is a transform coefficient of the final position in the scan area.

The context model relating to the flag information indicating whether the absolute value of the first transform coefficient is larger than 2 can be determined based on the number of the right or lower effective transform coefficients whose absolute value is larger than 2.

The context model for flag information indicating whether the first transform coefficient is greater than 2 is not limited to this, and the absolute value of n (n is a positive integer) transform coefficients previously scanned according to a predetermined scan order is greater than 2 Can be determined based on the number of large effective conversion coefficients.

Alternatively, the context model on the flag information indicating whether the absolute value of the first transform coefficient is larger than 2 may be determined based on the previously decoded GT2 flag information and the previously decoded in-group GT2 flag information in the corresponding coefficient group.

Alternatively, the flag information (hereinafter referred to as GT2 flag information) indicating whether the absolute value of the first transform coefficient is greater than 2 may be used as the GT2 flag of the previously scanned n (n is a positive integer) Information and the position of the first transform coefficient in the current block, the color component, and GT2 flag information of the adjacent right or lower n (n is a positive integer) transform coefficients, the transform coefficient of the first position in the scan area And whether or not the first transform coefficient is a transform coefficient of the final position in the scan area.

Alternatively, flag information (hereinafter referred to as GTm flag information) indicating whether the first transform coefficient is larger than m (m is an integer larger than 2) is n (n is a positive integer) scanned previously according to a predetermined scan order The GTm flag information of the transform coefficients, the position of the first transform coefficient in the current block, the chrominance component, and the GTm flag information of the adjacent right or lower n (n is a positive integer) transform coefficients, Whether it is a transform coefficient of the initial position, and whether or not the first transform coefficient is a transform coefficient of the final position in the scan area.

On the other hand, the binarization parameter information on the residual level value of the first transform coefficient may be determined based on the absolute level of the level of the peripheral effective transform coefficient on the right side or the lower side of the first transform coefficient.

For example, the binarization parameter information on the first transform coefficient may be determined based on the sum of the absolute levels of the values of the predetermined peripheral effective transform coefficients on the right side or the lower side of the first transform coefficient.

Alternatively, the binarization parameter information regarding the residual level value of the first transform coefficient may be determined based on the previously encoded level value.

Alternatively, the binarization parameter information on the first transform coefficient may include information on the level of n (n is an integer) transform coefficients previously scanned according to a predetermined scan order, the position of the first transform coefficient in the current block, (N is a positive integer) number of conversion coefficients on the lower side, whether the first conversion coefficient on the scan order is a conversion coefficient of the first position in the scan area, whether the first conversion coefficient on the scan order is Whether or not the first transform coefficient is a transform coefficient, whether the first transform coefficient in the scan order is a coefficient of an initial position in a coefficient group, the position of the first transform coefficient is a relative position in the scan region, and the like .

The entropy decoding unit 105 determines whether or not the position of the transform coefficient currently scanned in the scan region is [SRx, 0] (where SRx is an integer and SRx is the horizontal coordinate value of the right boundary pixel of the scan region on the basis of the left upper- (Y is an integer greater than 0 and less than or equal to SRy, and SRy represents a lower boundary of the scan region with respect to the upper left corner coordinate of the scan region in accordance with a predetermined scan order) The GT0 flag information of the transform coefficient currently scanned from the bit stream is not acquired and the value of the GT0 flag information can be determined to be 1. [

Likewise, the entropy decoding unit 105 determines that the position of the transform coefficient currently scanned in the scan region is [0, SRy] (where SRy is an integer and SRy is the vertical coordinate of the lower boundary of the scan region on the basis of the upper left corner coordinate of the scan region) (X, SRy) (where X is an integer greater than 0 and less than or equal to SRx, SRx is an integer equal to or greater than 0, The GT0 flag information of the currently scanned transform coefficient is not obtained from the bit stream and the value of the GT0 flag information can be determined to be 1 .

On the other hand, the entropy decoding unit 105 can determine the maximum number of GT1 flag information of the current effective conversion coefficient in the block, and receive the GT1 flag information in the current block from the bit stream within the maximum coefficient of the determined effective conversion coefficient . That is, when the entropy decoding unit 105 receives the maximum number of GT1 flag information of the effective conversion coefficient received from the bitstream, the entropy decoding unit 105 determines whether the GT1 flag information of the effective conversion coefficient exists in the bitstream I can not check it anymore.

The entropy decoding unit 105 can determine all non-zero effective conversion coefficients as the maximum number of GT1 flag information in the current block. Alternatively, the entropy decoding unit 105 can determine the maximum number of GT1 flag information in the current block based on the size of the scan area. For example, the entropy decoding unit 105 can determine the maximum number MaxCount_GT1 of the GT1 flag information based on the following expression (1).

Equation 1

In this case, sizeSR may mean the size (width) of the square scan area, and sizeSR may be (Sr_x + 1) * (Sr_y + 1). Sr_x can be the horizontal coordinate of the rightmost effective transformation coefficient pixel based on the upper left corner coordinate of the scan area. In other words, Sr_x can mean the horizontal coordinate of the right boundary pixel based on the upper left corner coordinate of the scan area. Sr_y may mean the vertical coordinate of the lowest effective conversion factor pixel based on the upper left corner coordinate of the scan area. In other words, Sr_y may mean the vertical coordinate of the lower boundary pixel based on the upper left corner coordinate of the scan area.

K1 can be the magnitude of the scan area and the adjustment factor between the GT1 flags. For example, it may be an integer greater than one. Th1 may be a predetermined threshold value. For example, Th1 may be 16,8. Those skilled in the art can easily understand that K1 and Th1 can have various values, without being limited thereto.

The entropy decoding unit 105 may determine the maximum number of GT2 flag information in the current block and receive GT2 flag information in the current block from the bit stream within the maximum coefficient of the determined effective transform coefficient. That is, when the entropy decoding unit 105 receives the maximum number of GT2 flag information of the effective conversion coefficient received from the bitstream, the entropy decoding unit 105 determines whether the GT2 flag information of the effective conversion coefficient exists in the bitstream I can not check it anymore.

The entropy decoding unit 105 can determine all non-zero effective conversion coefficients as the maximum number of GT2 flag information in the current block. Alternatively, the entropy decoding unit 105 can determine the maximum number of GT2 flag information in the current block based on the size of the scan area. For example, the entropy decoding unit 105 can determine the maximum number MaxCount_GT2 of the GT2 flag information based on the following expression (2).

Equation 2

In this case, sizeSR may mean the size (width) of the square scan area, and sizeSR may be (Sr_x + 1) * (Sr_y + 1). Sr_x can be the horizontal coordinate of the rightmost effective transformation coefficient pixel based on the upper left corner coordinate of the scan area. In other words, Sr_x can mean the horizontal coordinate of the right boundary pixel based on the upper left corner coordinate of the scan area. Sr_y may mean the vertical coordinate of the lowest effective conversion factor pixel based on the upper left corner coordinate of the scan area. In other words, Sr_y may mean the vertical coordinate of the lower boundary pixel based on the upper left corner coordinate of the scan area. K2 can be the magnitude of the scan area and the adjustment factor between GT2 flags. For example, it may be an integer greater than one. K2 may be a predetermined threshold value. For example, Th2 may be 16,8. Those skilled in the art can easily understand that K2 and Th2 can have various values, without being limited thereto.

The entropy decoding unit 105 can obtain information on the current intra-block coefficient group from the bitstream. Here, the information on the coefficient group may be flag information indicating whether or not the coefficient group includes at least one effective transform coefficient (or whether or not the coefficient group includes only a transform coefficient of zero). The flag information may be referred to as significant coefficient group flag information. The entropy decoding unit 105 can scan information on the current coefficient group intra-coefficient transform coefficients based on the information on the current coefficient group obtained from the bit stream. For example, if the information on the coefficient group indicates that the coefficient group does not contain at least one effective transform coefficient, the entropy decoding unit 105 sets the value of the transform coefficient in the coefficient group without scanning the information about the transform coefficient 0 < / RTI > If the information on the coefficient group indicates that the coefficient group includes at least one effective transform coefficient, the entropy decoding unit 105 scans information on the transform coefficient according to a predetermined scan order to acquire a transform coefficient in the coefficient group .

At this time, the entropy decoding unit 105 can determine one coefficient group for every predetermined K number of transform coefficients included in the scan region (K is an integer) scanned according to a predetermined scan order. That is, one coefficient group may include K transform coefficients. In this case, the scan order may be a forward scan order that is the opposite direction of the predetermined reverse scan order.

Accordingly, the entropy decoding unit 105 can determine a coefficient group by scanning in a forward scan order from a DC coefficient that is a coefficient adjacent to the upper left corner in the current block. If the number of transform coefficients included in the current block is not an integral multiple of K, the last coefficient group among the groups of coefficients scanned according to the forward scan order may include a smaller number of transform coefficients.

However, the present invention is not limited to this, and the entropy decoding unit 105 may perform a reverse scan order in which the coefficients located at the lower right end among the transform coefficients included in the current block are scanned up to a coefficient located at the upper left of the transform coefficients included in the current block It will be readily appreciated by those skilled in the art that scanning may be performed in accordance with the present invention to determine a coefficient group.

Those skilled in the art can easily understand that the entropy decoding unit 105 can determine a coefficient group according to a predetermined scanning order without acquiring information on the current intra-block coefficient group from the bitstream. The reason for determining the coefficient group is to perform an operation (such as sign data hiding) for the entropy decoding unit 105 to process according to the coefficient group. If one of the groups of coefficients scanned according to a predetermined scan order includes only one transform coefficient, the entropy decoding unit 105 does not acquire information on the corresponding coefficient group from the bitstream, Information can be obtained from the bitstream.

The entropy decoding unit 105 can determine that the sign of at least one transform coefficient is hidden for each coefficient group included in the current block. For example, the entropy decoding unit may decide to hide the sign of one or two transform coefficients for each coefficient group included in the current block.

The entropy decoding unit 105 may scan the information on the transform coefficients in the quadrangular scan area according to a predetermined scan order. The predetermined scan order may include a reverse zigzag scan order, a reverse diagonal scan order, a reverse vertical scan order, and a horizontal scan order. However, those skilled in the art will readily understand that the predetermined scan order is not limited to the above-mentioned reverse scan order and may include various reverse scan orders.

The entropy decoding unit 105 can obtain the transform coefficients of the current block based on the information about the scanned transform coefficients.

The image restoring unit 120 may generate a residual block of the current block by performing inverse quantization and inverse transformation on the transform coefficients of the current block.

The image restoring unit 120 may restore the current block based on the residual block of the current block.

The image restoring unit 120 may perform inter-prediction or intra-prediction on the current block to generate a prediction block of the current block. The image restoring unit 120 may restore the current block based on the prediction block of the current block and the residual block of the current block. That is, the image restoring unit 120 may restore the values of the pixels included in the current block by adding the values of the pixels included in the prediction block and the values of the pixels included in the residual block.

The video decoding apparatus 100 may include an image decoding unit (not shown), and the image decoding unit (not shown) may include an entropy decoding unit 105 and an image restoring unit 120. The video decoding unit will be described with reference to FIG.

In step S105, the video decoding apparatus 100 may determine a rectangular scan area including all the effective transform coefficients in the current block. At this time, the coordinates specifying the quadrangular scan area include the horizontal coordinate of the effective conversion coefficient pixel located at the rightmost of the effective conversion coefficients in the current block and the coordinates of the effective conversion coefficient pixel located at the lowermost one of the effective conversion coefficients in the current block Vertical direction coordinates. The video decoding apparatus 100 may obtain information on the coordinates specifying the quadrangular scan region from the bit stream and determine the quadrangular scan region based on the coordinates specifying the obtained quadrangular scan region.

In step S110, the video decoding apparatus 100 may scan the information on the transform coefficients in the quadrangular scan area according to a predetermined scan order. The predetermined scan order may include a reverse zigzag scan order or a reverse diagonal scan order. The zigzag scan order may include a vertical priority zigzag scan order or a horizontal priority zigzag scan order.

In step S115, the video decoding apparatus 100 may acquire the transform coefficients of the current block based on the information about the scanned transform coefficients.

In step S120, the video decoding apparatus 100 may perform inverse quantization and inverse transform on the transform coefficients of the current block to generate a residual block of the current block.

In step S125, the video decoding apparatus 100 can restore the current block based on the residual block. The video decoding apparatus 100 performs inter prediction or intra prediction to generate a prediction block of a current block. The video decoding apparatus 100 adds the pixel values of the residual blocks to the pixel values included in the prediction blocks of the current block The pixel value of the reconstruction block of the current block can be generated.

The video encoding apparatus 150 according to various embodiments includes an entropy encoding unit 155 and a bitstream generation unit 170.

The entropy encoding unit 155 can perform entropy encoding on the syntax element related to the intra-block transformation coefficient. The entropy encoding unit 155 scans the two-dimensional array information about the current intra-block transform coefficients according to a predetermined scan order to generate one-dimensional array information about the current intra-block transform coefficients, Can be entropy-encoded with respect to the one-dimensional array information about the one-dimensional array information.

The syntax element related to the conversion coefficient may be a flag indicating whether the conversion coefficient is larger than a predetermined value. At this time, the predetermined value may be a value equal to or greater than zero. For example, 0, 1 or 2. It may also be a syntax element indicating the absolute level of the remaining level with respect to the transform coefficients. That is, the absolute value of the remaining level may indicate an absolute value difference between a predetermined absolute value determined based on whether the absolute value of the conversion coefficient is larger than a predetermined value. The syntax element related to the effective conversion coefficient may be a syntax element related to the sign of the effective conversion coefficient.

First, the entropy encoding unit 155 may perform binarization on the syntax element to generate an empty string, and perform binary arithmetic encoding on the empty string to generate entropy-encoded information for the syntax element. At this time, the binarization may be performed in the binarization unit 160, and the binary arithmetic encoding may be performed in the binary arithmetic encoding unit 165.

The binarization unit 160 may perform binarization on a predetermined syntax element to generate an empty string. The binarization unit 160 may perform binarization on a predetermined syntax element based on a predetermined binarization method. The predetermined binarization method may include a fixed length binarization method, a Rice binarization method, an exponential Golomb binarization method, and a Golomb-Rice binarization method. Or the predetermined binarization method may be a binarization method in which the first binarization method and the second binarization method are combined. For example, the binarization unit 160 may binarize a portion of a syntax element based on a first binarization method to generate a first bin string, and for another portion of the syntax element, a second binarization method To generate a second bin string. &Lt; RTI ID = 0.0 > Here, the first empty string may be part of the empty string of the syntax element, and the second empty string may be another part of the empty string of the syntax element. A portion of the empty string may be a prefix or a suffix.

The binary arithmetic coding unit 165 may perform binary arithmetic coding based on a predetermined context model for an empty string regarding a predetermined syntax element. Alternatively, the binary arithmetic coding unit 165 may perform binary arithmetic coding on a bin string relating to a predetermined syntax element without a predetermined context model. At this time, the probability of 0 or 1 for the current binary arithmetic coding bin is fixed to 0, and binary arithmetic coding can be performed based on this probability.

The entropy encoding unit 155 can obtain the transform coefficients of the current block. That is, the video encoding apparatus 150 can generate a prediction block of the current block by performing inter prediction or intra prediction, and generates a residual block of the current block based on the original block of the current block and the prediction block of the current block can do. The video encoding apparatus 150 may convert and quantize the residual block of the current block to generate a transform coefficient of the current block. The entropy encoding unit 155 may obtain the transform coefficients of the generated current block.

The entropy encoding unit 155 determines information on the transform coefficients of the current block, generates information about the transform coefficients of the current block in accordance with a predetermined scan order, generates one-dimensional array information on the transform coefficients of the current block , And entropy encoding can be performed on the one-dimensional array information. The predetermined scan order may be a sequence according to the reverse zigzag scan or an order according to the reverse diagonal scan. However, the order may be various scan orders such as a reverse horizontal scan order and a scan order according to reverse vertical scan. The predetermined scan order may be determined based on at least one of the horizontal coordinate of the effective conversion coefficient pixel located at the rightmost position in the current block and the vertical direction of the effective conversion coefficient pixel located at the bottommost position in the current block. The entropy encoding unit 155 can determine a predetermined scan order based on the size of the horizontal direction coordinate value and the size of the vertical direction coordinate value. For example, if the horizontal direction coordinate value is larger than the vertical direction coordinate value, the entropy encoding unit 155 can determine the reverse vertical scanning order in a predetermined scanning order. The entropy encoding unit 155 may determine the horizontal scan order in the reverse direction as a predetermined scan order when the vertical direction coordinate value is larger than the horizontal direction coordinate value.

Alternatively, the entropy encoding unit 155 may determine the reverse direction vertical priority zigzag scan order in a predetermined scan order when the horizontal direction coordinate value is larger than the vertical direction coordinate value. The entropy encoding unit 155 can determine the horizontal priority zigzag scan order in the reverse direction in a predetermined scan order when the vertical direction coordinate value is larger than the horizontal direction coordinate value. The entropy encoding unit 155 may determine one of the vertical first zigzag scan order and the horizontal priority zigzag scan order in the reverse direction in a predetermined scan order when the vertical direction coordinate value is equal to the horizontal direction coordinate value.

Alternatively, if the horizontal direction coordinate value is larger than the vertical direction coordinate value, the entropy encoding unit 155 can determine the reverse horizontal zigzag scanning order in a predetermined scanning order. The entropy encoding unit 155 may determine a horizontal first zigzag scan order in the reverse direction in a predetermined scan order when the horizontal direction coordinate value is not larger than the vertical direction coordinate value.

First, the entropy encoding unit 155 can determine a rectangular scan area including all the effective transform coefficients in the current block. In this case, the square scan region includes all the effective transformation coefficients in the current block, and the remaining regions in the current block excluding the rectangular scan region may include only transformation coefficients having a value of 0, which is not an effective transformation coefficient. The entropy encoding unit 155 may determine the coordinates specifying the quadrangular scan area and may entropy encode information on the coordinates specifying the quadrangular scan area. That is, the entropy encoding unit 155 may generate a bin string by performing a binarization based on a predetermined binarization method on a syntax element related to a coordinate specifying a quadrangular scan area. Here, the predetermined binarization method may be at least one of a fixed length binarization method and a cutting type unary binarization method.

The entropy encoding unit 155 can perform binary arithmetic coding based on the context model on the bin string regarding the syntax element related to the coordinates specifying the quadrangular scan area. At this time, the context model may be determined based on at least one of the size of the current block, the color component of the current block, and the empty index. The color component may include a luminance component and a chrominance component. The empty index may be information indicating the position of the bin that is currently binary arithmetic-coded among the bin strings related to the syntax element.

The entropy encoding unit 155 may generate at least one of binarization based on information on the scanned transform coefficients and binary arithmetic encoding based on the context model of the transform coefficients to generate entropy-encoded information.

The first information on the transform coefficients is information indicating whether the absolute value of the current transform coefficient is larger than a predetermined value, the residual level absolute value information and the sign information of the current transform coefficient, and the second information on the transform coefficients is the binarization parameter Information, the entropy encoding unit 155 may perform binarization on the first information on the transform coefficients based on the second information to generate a bin string for the first information. The entropy encoding unit 155 may perform binary arithmetic encoding on a bin string related to the first information to generate entropy-encoded information.

The second information includes information on at least one second transform coefficient previously scanned in accordance with a predetermined scan order, information on the position, color component, right or lower peripheral transformation coefficient of the first transform coefficient in the current block, 1 < / RTI > conversion coefficient. For example, the binarization parameter information on the first transform coefficient may be determined based on the absolute level of the level of the peripheral effective transform coefficient on the right side or the lower side of the first transform coefficient. The binarization parameter information on the first transform coefficient may be determined based on the sum of the absolute levels of the levels of the peripheral effective transform coefficients on the right side or the lower side of the first transform coefficient.

Alternatively, the binarization parameter information on the first transform coefficient may include information on the level of n (n is an integer) transform coefficients previously scanned according to a predetermined scan order, the position of the first transform coefficient in the current block, (N is a positive integer) number of conversion coefficients on the lower side, whether the first conversion coefficient on the scan order is a conversion coefficient of the first position in the scan area, whether the first conversion coefficient on the scan order is Whether the transform coefficient is a transform coefficient, whether or not the first transform coefficient on the scan order is a coefficient of the first position in the coefficient group, and the like.

If the information on the transform coefficients is information indicating whether the absolute value of the current transform coefficient is larger than a predetermined value, the residual level absolute value information, and the sign information of the current transform coefficient, the entropy coding unit 155 calculates You can perform binarization on the information to create an empty string. The entropy encoding unit 155 may perform binary arithmetic coding based on the context model on the bin strings to generate binary arithmetic coded information. The context model of the first transform coefficient among the context models related to the transform coefficients includes information on at least one second transform coefficient previously scanned in accordance with a predetermined scan order, position of the first transform coefficient in the current block, Information about the right or lower peripheral transformation coefficient, and the scan position of the first transformation coefficient.

The context model relating to the flag information indicating whether the first conversion coefficient is larger than 0 can be determined based on the number of the right or lower effective conversion coefficients whose absolute values are larger than zero.

The context model relating to the flag information indicating whether the first conversion coefficient is larger than 1 can be determined based on the number of the right or lower effective conversion coefficients whose absolute values are larger than 1.

The context model of the flag information indicating whether the first transform coefficient is greater than 1 is not limited to this, and the absolute value of n (n is a positive integer) transform coefficients previously scanned according to a predetermined scan order is larger than 1 Can be determined based on the number of large effective conversion coefficients.

The context model relating to the flag information indicating whether the first conversion coefficient is larger than 2 can be determined based on the number of the right or lower effective conversion coefficients whose absolute values are larger than 2.

The entropy encoding unit 155 encodes the position of the transform coefficient currently scanned in the scan region by [SRx, 0] (where SRx is an integer and SRx is the horizontal coordinate value of the right boundary pixel of the scan region on the basis of the left upper- (Y is an integer greater than 0 and less than or equal to SRy, and SRy represents a lower boundary of the scan region with respect to the upper left corner coordinate of the scan region in accordance with a predetermined scan order) (I.e., the vertical direction coordinate value of the pixel), the GT0 flag information of the currently scanned conversion coefficient may not be generated.

Likewise, the entropy encoding unit 155 determines whether or not the position of the transform coefficient currently scanned in the scan region is [0, SRy] (where SRy is an integer and SRy is the vertical coordinate of the lower boundary of the scan region on the basis of the upper left corner coordinate of the scan region (X, SRy) (where X is an integer greater than 0 and less than or equal to SRx, SRx is an integer equal to or greater than 0, (I.e., the vertical direction coordinate value of the boundary pixel). If the transform coefficients of the positions are all zeros, the GT0 flag information of the currently scanned transform coefficients may not be generated.

On the other hand, the entropy encoding unit 155 can determine the maximum number of GT1 flag information of the current intra-block effective transform coefficient and generate the GT1 flag information in the current block within the maximum coefficient of the determined effective transform coefficient. That is, if the entropy encoding unit 155 generates the maximum number of GT1 flag information of the effective conversion coefficient, the entropy encoding unit 155 may not generate the GT1 flag information of the effective conversion coefficient thereafter.

The entropy encoding unit 155 can determine all non-zero effective conversion coefficients as the maximum number of GT1 flag information in the current block. Or the entropy encoding unit 155 can determine the maximum number of GT1 flag information in the current block based on the size of the scan area. For example, the entropy encoding unit 155 can determine the maximum number of GT1 flag information MaxCount_GT1 based on Equation (3) below.

Equation 3

In this case, sizeSR may mean the size (width) of the square scan area, and sizeSR may be (Sr_x + 1) * (Sr_y + 1). Sr_x can be the horizontal coordinate of the rightmost effective transformation coefficient pixel based on the upper left corner coordinate of the scan area. In other words, Sr_x can mean the horizontal coordinate of the right boundary pixel based on the upper left corner coordinate of the scan area. Sr_y may mean the vertical coordinate of the lowest effective conversion factor pixel based on the upper left corner coordinate of the scan area. In other words, Sr_y may mean the vertical coordinate of the lower boundary pixel based on the upper left corner coordinate of the scan area. K1 can be the magnitude of the scan area and the adjustment factor between the GT1 flags. For example, K1 may be an integer greater than one. Th1 may be a predetermined threshold value. For example, Th1 may be 16,8. Those skilled in the art can easily understand that K1 and Th1 can have various values, without being limited thereto.

The entropy encoding unit 155 can determine the maximum number of GT2 flag information in the current block and generate the GT2 flag information in the current block within the maximum coefficient of the determined effective transform coefficient. That is, if the entropy encoding unit 155 generates the maximum number of GT2 flag information of the effective conversion coefficient, the entropy encoding unit 155 may not generate the GT2 flag information of the effective conversion coefficient thereafter.

The entropy encoding unit 155 can determine all non-zero effective conversion coefficients as the maximum number of GT2 flag information in the current block. Alternatively, the entropy encoding unit 155 can determine the maximum number of GT2 flag information in the current block based on the size of the scan area. For example, the entropy encoding unit 155 can determine the maximum number MaxCount_GT2 of the GT2 flag information based on the following expression (4).

Equation 4

In this case, sizeSR may mean the size (width) of the square scan area, and sizeSR may be (Sr_x + 1) * (Sr_y + 1). Sr_x can be the horizontal coordinate of the rightmost effective transformation coefficient pixel based on the upper left corner coordinate of the scan area. In other words, Sr_x can mean the horizontal coordinate of the right boundary pixel based on the upper left corner coordinate of the scan area. Sr_y may mean the vertical coordinate of the lowest effective conversion factor pixel based on the upper left corner coordinate of the scan area. In other words, Sr_y may mean the vertical coordinate of the lower boundary pixel based on the upper left corner coordinate of the scan area. K2 can be the magnitude of the scan area and the adjustment factor between GT2 flags. For example, K2 may be an integer greater than one. Th2 may be a predetermined threshold value. For example, Th2 may be 16,8. Those skilled in the art can easily understand that K2 and Th2 can have various values, without being limited thereto.

The entropy encoding unit 155 can generate information on the current intra-block coefficient group. The information on the coefficient group may be flag information indicating whether the coefficient group includes at least one effective transform coefficient. At this time, the entropy encoding unit 155 can determine one coefficient group for every predetermined K number of transform coefficients included in the scan region (K is an integer) scanned according to the scan order. That is, one coefficient group may include K transform coefficients. In this case, the scan order may be a forward scan order that is the opposite direction of the predetermined reverse scan order. The predetermined backward scan order referred to herein may mean a scan order from a coefficient located at the lower right of the transform coefficients included in the current block to a coefficient located at the upper left of the transform coefficients included in the current block.

Accordingly, the entropy encoding unit 155 can determine the coefficient group by scanning in the forward scan order from the DC coefficient, which is a coefficient adjacent to the upper left corner in the current block. If the number of transform coefficients included in the current block is not an integral multiple of K, the last coefficient group among the groups of coefficients scanned according to the forward scan order may include a smaller number of transform coefficients. However, the present invention is not limited to this, and the entropy coding unit 155 may perform the inverse scanning order in which the coefficients located in the lower right of the transform coefficients included in the current block are scanned up to the coefficient located in the upper left of the transform coefficients included in the current block It will be readily appreciated by those skilled in the art that scanning may be performed in accordance with the present invention to determine a coefficient group.

If one of the groups of coefficients scanned according to a predetermined scan order includes only one transform coefficient, the entropy encoding unit 155 does not generate information about the corresponding coefficient group and outputs the GT0 flag information immediately Can be generated.

The entropy encoding unit 155 may determine whether to hide the sign of at least one transform coefficient for each coefficient group included in the current block. For example, the entropy encoding unit 155 may determine It can be determined that the sign of one or two transform coefficients is hidden for each coefficient group included in the current block.

The entropy encoding unit 155 may scan the information on the transform coefficients in the quadrangular scan area according to a predetermined scan order. The predetermined scan order may include a reverse zigzag scan order, a reverse diagonal scan order, a reverse vertical scan order, and a horizontal scan order. However, those skilled in the art will readily understand that the predetermined scan order is not limited to the above-mentioned reverse scan order and may include various reverse scan orders.

The bitstream generator 170 may generate a bitstream including entropy-encoded information. That is, the bitstream generating unit 170 may scan the information about the transform coefficients in the entropy encoding unit 155 and generate a bitstream including the entropy-encoded information based on the information about the scanned transform coefficients .

The bitstream generating unit 170 may generate a bitstream including information on coordinates specifying a quadrangle scan area, which is an area for scanning information on transform coefficients. At this time, the information on the coordinates specifying the quadrangular scan area is obtained by dividing the horizontal coordinate value of the effective conversion coefficient pixel located at the rightmost of the effective conversion coefficient pixels included in the current block and the horizontal coordinate value of the effective conversion coefficient pixels included in the current block And information indicating the vertical coordinate value of the effective transformation coefficient pixel located at the lowermost position. However, the present invention is not limited to this, and the information on the coordinates specifying the quadrangular scan area may be obtained by adding the horizontal coordinate values of the effective conversion coefficient pixels located at the rightmost of the effective conversion coefficient pixels included in the current block, And information indicating a coordinate value having a larger value among the vertical coordinate values of the effective conversion coefficient pixel located at the lowermost one of the coefficient pixels. In other words, the bitstream generating unit 170 generates the bit stream of the effective transform coefficient pixel located at the bottom of the effective transform coefficient pixels included in the current block and the horizontal direction coordinate value of the effective transform coefficient pixel located at the right- Even if the vertical coordinate values of the effective conversion coefficient pixels are different from each other, the square scan region can be determined based on the larger of the rectangular scan regions. In this case, a scan area of a square larger than a rectangular scan area can be determined, but the video encoding device 150 transmits only information indicating only a coordinate value in one direction, thereby reducing the number of signaling bits.

The video encoding apparatus 150 may include an image encoding unit (not shown), and the image encoding unit (not shown) may include an entropy encoding unit 155 and a bitstream generating unit 170. The image encoding unit will be described with reference to FIG.

Referring to FIG. 1D, in operation S150, the video encoding apparatus 150 may obtain the transform coefficients of the current block. The current block may be a data unit that can be used in the process of attaching / decrypting an image described with reference to FIGS.

The video encoding apparatus 150 can generate a prediction block of the current block by performing inter prediction or intra prediction and generate a residual block of the current block based on the original block of the current block and the prediction block of the current block have. The video encoding apparatus 150 may transform and quantize the residual block of the current block to generate transform coefficients of the current block.

In step S155, the video encoding apparatus 150 may determine a rectangular scan area including all effective transformation coefficients in the current block. In this case, the square scan region includes all the effective transform coefficients in the current block, and the remaining region in the current block excluding the square scan region may include only coefficients having a value of 0, which is not an effective transform coefficient. The video encoding apparatus 150 may determine the coordinates specifying the quadrangular scan region and entropy-encode information on the coordinates specifying the quadrangular scan region. That is, the video encoding apparatus 150 may generate a bin string by performing binarization on the syntax element information on the coordinates specifying the quadrangular scan area based on a predetermined binarization method. Here, the predetermined binarization method may be at least one of a fixed length binarization method and a cutting type unary binarization method. The video encoding apparatus 150 may perform binary arithmetic coding based on the context model on the bin string regarding the syntax regarding the coordinates specifying the quadrangular scan area. At this time, the context model may be determined based on at least one of the size of the current block, the color component of the current block, and the empty index.

In step S160, the video encoding device 150 may scan the information on the transform coefficients included in the quadrangular scan area according to a predetermined scan order. The information on the transform coefficient may include flag information indicating whether the transform coefficient is larger than a predetermined value. At this time, the predetermined value may be at least one of 0, 1, and 2. The residual level information of the transform coefficient, the sign information of the transform coefficient, and the binarization parameter information. The binarization parameter may include at least one of a race parameter and various binarization parameters. The predetermined scan order may include a reverse zigzag scan order, a reverse diagonal scan order, a reverse vertical scan order, and a horizontal scan order. However, those skilled in the art will readily understand that the predetermined scan order is not limited to the above-mentioned reverse scan order and may include various reverse scan orders.

In step S165, the video encoding device 150 can generate entropy-encoded information by entropy encoding based on information about the scanned transform coefficients. The video encoding apparatus 150 may generate at least one of binarization based on information on the scanned transform coefficients and binary arithmetic encoding based on the context model to generate entropy-encoded information. The first information on the transform coefficients is information indicating whether the absolute value of the current transform coefficient is larger than a predetermined value, the residual level absolute value information, and the current transform coefficient information, and the second information on the effective transform coefficients is binarized In case of the parameter information, the video encoding apparatus 150 may generate bin strings for the first information by performing binarization based on the second information on the first information on the effective transform coefficients. The video encoding apparatus 150 may perform binary arithmetic coding on a bin string related to the first information to generate entropy-encoded information.

The second information includes information on at least one second transform coefficient previously scanned in accordance with a predetermined scan order, position and color components of the first transform coefficient in the current block, information on the right or lower peripheral transformation coefficient, 1 < / RTI > conversion coefficient. On the other hand, the binarization parameter information on the first transform coefficient can be determined based on the absolute level of the level of the peripheral effective transform coefficient on the right side or the lower side of the first transform coefficient. For example, the binarization parameter information on the first transform coefficient may be determined based on the sum of the absolute levels of the levels of the peripheral effective transform coefficients on the right side or the lower side of the first transform coefficient.

If the information on the transform coefficients is the information indicating whether the absolute value of the current effective transform coefficient is larger than a predetermined value, the residual level absolute value information, and the current effective transform coefficient information, the video coding apparatus 150 outputs the transform coefficients Can be binarized to generate a bin string. The video encoding apparatus 150 may perform binary arithmetic coding based on the context model on the valid transform coefficients for bin strings to generate binary arithmetic coded information. The context model of the first transform coefficient among the context models related to the valid transform coefficients includes information on at least one second transform coefficient previously scanned according to a predetermined scan order, position of the first transform coefficient in the current block, Information on the color component, the right or lower peripheral transformation coefficient, and the scan position of the first transformation coefficient.

In operation S170, the video encoding apparatus 150 may generate a bitstream including entropy-encoded information. The video encoding apparatus 150 may scan the information on the transform coefficients in the entropy encoding unit 155 and generate a bit stream including the entropy encoded information based on the information about the scanned transform coefficients.

In addition, the video encoding device 150 may generate a bitstream including information on coordinates specifying a quadrangular scan area, which is an area for scanning information on the transform coefficients.

FIG. 1E shows a block diagram of an image decoding unit 6000 according to various embodiments.

The image decoding unit 6000 according to various embodiments performs operations to encode image data in a video decoding unit (not shown) of the video decoding apparatus 100. [

Referring to FIG. 1E, the entropy decoding unit 6150 parses the encoded image data to be decoded and the encoding information necessary for decoding from the bitstream 6050. The encoded image data is a quantized transform coefficient, and the inverse quantization unit 6200 and the inverse transform unit 6250 reconstruct the residue data from the quantized transform coefficients. The entropy decoding unit 6150 of FIG. 1E may correspond to the entropy decoding unit 105 of FIG. 1A.

The intra prediction unit 6400 performs intra prediction on a block-by-block basis. The inter-prediction unit 6350 performs inter-prediction using the reference image obtained in the reconstruction picture buffer 6300 for each block. The spatial data for the block of the current image 6050 is restored by adding the predictive data and residue data for each block generated by the intra predictor 6400 or the

inter predictor

6350, 6450 and the SAO performing unit 6500 may perform loop filtering on the data of the reconstructed spatial region and output the filtered reconstructed image 6600. [ In addition, restored images stored in the restored picture buffer 6300 can be output as a reference image.

In order to decode the image data in the decoding unit (not shown) of the video decoding apparatus 100, the stepwise operations of the image decoding unit 6000 according to various embodiments may be performed block by block.

FIG. 1F shows a block diagram of an image encoding unit according to various embodiments.

The image encoding unit 7000 according to various embodiments performs operations to encode image data in an image encoding unit (not shown) of the video encoding device 150.

That is, the intra predictor 7200 performs intraprediction on a block-by-block basis among the current image 7050, and the inter-prediction unit 7150 performs intra prediction on the current image 7050 and the reference image obtained from the reconstructed picture buffer 7100 To perform inter prediction.

The transform unit 7250 generates residue data by subtracting the prediction data for each block output from the intra prediction unit 7200 or the inter prediction unit 7150 from the data for the block to be encoded of the current image 7050, And quantization unit 7300 may perform conversion and quantization on the residue data and output the quantized transform coefficients on a block-by-block basis. The inverse quantization unit 7450 and the inverse transformation unit 7500 can perform inverse quantization and inverse transformation on the quantized transform coefficients to restore the residue data in the spatial domain. Residue data of the reconstructed spatial region is reconstructed into spatial domain data for a block of the current image 7050 by adding predictive data for each block output from the intra predictor 7200 or the inter predictor 7150 . The deblocking unit 7550 and the SAO performing unit perform in-loop filtering on the data of the reconstructed spatial region to generate a filtered reconstructed image. The generated restored image is stored in the restored picture buffer 7100. The reconstructed images stored in the reconstructed picture buffer 7100 can be used as reference images for inter prediction of other images. The entropy encoding unit 7350 entropy-codes the quantized transform coefficients, and the entropy-encoded coefficients can be output as a bitstream 7400. The entropy encoding unit 7350 of FIG. 1F may correspond to the entropy encoding unit 155 of FIG. 1C.

In order for the image encoding unit 7000 according to various embodiments to be applied to the video encoding device 150, the stepwise operations of the image encoding unit 7000 according to various embodiments may be performed for each block.

Hereinafter, '0' and '1' shown for the pixels in the current block of FIG. 2 and FIGS. 3A and 3B are assumed to be values of the effective conversion coefficient flag (flag indicating whether the absolute value of the coefficient is greater than 0) The method of scanning the in-block transform coefficients will be described in detail.

Referring to FIG. 2, the current block 200 is a block including a plurality of transform coefficients. The current block 200 is a data unit for performing an inverse transform operation, and may be a block of MxN (M, N is a positive integer) size. For example, as shown in FIG. 2, the current block 200 may be a 16x16 block.

The video decoding apparatus 100 may divide the current block 200 into coefficient groups (or sub-blocks) 205 having a predetermined size. The coefficient group may be a block of size XxY (where X and Y are positive integers). For example, as shown in FIG. 2, the coefficient group 205 may be a 4x4 block.

The video decoding apparatus 100 performs a process of scanning the current block 200 from the upper left transform coefficient to the lower right transform coefficient in accordance with the forward scan order, 210 from the bit stream. Information on the coordinates of the pixels 210 of the final effective conversion coefficients may include information on the horizontal direction coordinates of the pixels of the final effective conversion coefficients and information on the vertical direction coordinates of the pixels of the final effective conversion coefficients.

The video decoding apparatus 100 obtains the coordinates of the pixel 210 of the final effective conversion coefficient based on the information on the coordinates of the pixel 210 of the final effective conversion coefficient, The information of the transform coefficient may be scanned from the effective transform coefficient related to the final effective transform coefficient 210 according to a predetermined reverse scan order 215. [ For example, as illustrated in FIG. 2, the predetermined reverse scan order 215 may be a reverse diagonal scan order.

The video decoding apparatus 100 may scan the coefficient groups 205 according to a predetermined scanning order and perform a scanning operation on each coefficient group 205 according to a predetermined scanning order. The video decoding apparatus 100 may scan information about the coefficient groups according to a predetermined scanning order with respect to the coefficient groups. Information about the coefficient group may be obtained or derived from the bitstream. The information about the coefficient group may be derived to indicate that it includes at least one effective transform coefficient for the first coefficient group scanned according to the forward (reverse) scan order and for the last coefficient group. That is, the information about the coefficient group may not be included in the bitstream for the first coefficient group and the last coefficient group scanned in the forward (reverse) scan order.

At this time, the video decoding apparatus 100 may determine a predetermined reverse scan order based on at least one of the size of the block and the prediction mode. For example, when the current block size is 4x4 and the prediction mode of the current block is the intra prediction mode, the video decoding apparatus 100 may set one of the reverse horizontal scanning order, vertical scanning order, It can be determined in reverse scan order. When the current block size is 8x8 and the prediction mode of the current block is the intra prediction mode, the video decoding apparatus 100 performs one of the reverse horizontal scanning order, the vertical scanning order, or the diagonal scanning order in a predetermined reverse scan Can be determined in order.

The video decoding apparatus 100 can determine the reverse diagonal scanning order in a predetermined reverse scanning order if the current block size is not 4x4 or 8x8 or if the prediction mode of the current block is not the inter prediction mode.

When the video decoding apparatus 100 indicates that the information on the coefficient group 205 includes at least one coefficient of validity in the coefficient group 205, The information on the transform coefficients in the coefficient group can be scanned according to a predetermined scanning order 215. [

On the other hand, the video decoding apparatus 100 may determine that at least one sign among the effective transform coefficients included in each coefficient group 205 is hidden.

Referring to FIG. 3A, a current block 300 is a block including a plurality of transform coefficients. The current block 300 is a unit of data for performing an inverse transform operation, and may be a block of MxN (M, N is a positive integer) size. For example, as shown in FIG. 3A, the current block 300 may be a 16x16 block.

Referring to FIG. 3A, the video decoding apparatus 100 may determine a rectangular scan area 340 including all the effective transform coefficients existing in the current block 300. At this time, the quadrangular scan region 340 may be determined by the coordinates of the pixel 330 located at the lower right of the quadrangular scan region 340. The horizontal coordinate of the pixel 330 positioned at the lower right of the scan region 340 is the horizontal coordinate of the effective transformation coefficient pixel 320 located at the rightmost of all the effective transformation coefficients in the current block 300 have. The vertical direction coordinate of the pixel 330 positioned at the lower right of the scan region 340 is the vertical direction coordinate of the effective transformation coefficient pixel 310 located at the bottom of all the effective transformation coefficients in the current block 300 have. The information about the pixel 330 may include information about the upper left corner position of the pixel 330. The information about the pixel 330 may include information about the position of the bottom right corner of the pixel 330. [

The video decoding apparatus 100 receives information on the coordinates of the pixel 330 specifying the quadrangular scan region 340 from the bit stream and generates the quadrangular scan region 340 based on the information about the received pixel 330. [ Can be determined. The video decoding apparatus 100 can scan information on the transform coefficients from the pixel 330 to the upper left pixel 345 of the rectangular scan area 340 according to a predetermined reverse scan order 355. [ At this time, the coefficient group may be determined for every K (K is a positive integer) scan coefficient scanned according to a predetermined forward scan order from the upper left transform coefficient of the rectangular scan region 340. [ It is easily understood by those skilled in the art that the number of K (K is a positive integer) scan coefficient scanned according to a predetermined reverse scan order can be determined from the transform coefficient at the lower right end. Details of the coefficient group will be described later with reference to FIG. 3B.

On the other hand, the video decoding apparatus 100 can determine that a sign for at least one effective transform coefficient is hidden for each coefficient group, and can restore the sign for at least one effective transform coefficient that is hidden . Details of performing the operation of restoring the hidden code for each coefficient group will be described later with reference to FIG. 3B.

The video decoding apparatus 100 can determine a coefficient group for each of K (K is a positive integer) conversion coefficient pixels according to a predetermined scanning order 355 in the current block 350 in the forward direction. The video decoding apparatus 100 may determine a coefficient group including K transform coefficient pixels. For example, as shown in FIG. 3B, the video decoding apparatus 100 may determine the coefficient group 360 for every 16 pixels.

The video decoding apparatus 100 determines that a sign for at least one effective transform coefficient is hidden for every coefficient group 360 and a sign for at least one effective transform coefficient for each coefficient group 360 is You can decide that it is hidden. For example, the video decoding apparatus 100 can determine that a sign (Sign) for at least one effective transform coefficient is hidden for the current coefficient group based on the distance of previously decoded effective transform coefficients in the current coefficient group . Specifically, the video decoding apparatus 100 encodes a sign for at least one effective transform coefficient for the current coefficient group based on the distance between the first effective transform coefficient and the last valid transform coefficient scanned in a predetermined reverse scan order, Can be determined to be hidden. In this case, the distance may be a difference in the positions of the coefficients scanned in the reverse scan order.

For example, when the distance between the first effective conversion coefficient and the last effective conversion coefficient scanned according to a predetermined reverse scan order is greater than a predetermined value, the video decoding apparatus 100 may determine It can be determined that the sign is hidden. At this time, the predetermined value may be various integer values. For example, the predetermined value may be three.

If it is determined that the sign for at least one effective transform coefficient is hidden for the current coefficient group, the video decoding apparatus 100 determines whether or not the current coefficient group includes at least A hidden code for one effective transform coefficient can be restored. For example, when the parity sum with respect to the level of the effective transform coefficients in the current coefficient group is odd or even, the video decoding apparatus 100 determines the sign of at least one effective transform coefficient as 0 or 1 . At this time, the sign of the effective transform coefficient to be reconstructed may include a sign related to the final effective transform coefficient scanned in the reverse scan order. However, it is easily understood by those skilled in the art that a code at a predetermined position in a coefficient group can be restored according to a predetermined scanning order without being limited thereto.

The video decoding apparatus 100 acquires information on the coefficient group from the bitstream according to a predetermined scanning order in the reverse direction and when the information on the coefficient group indicates that the coefficient group includes at least one transform coefficient, Information about the transform coefficient in the coefficient group can be scanned. When the information on the coefficient group indicates that the coefficient group includes only the transform coefficient having a value of 0, all of the transform coefficients in the coefficient group can be determined as 0.

If the number of transform coefficients included in the square scan region in the current block 300 is not K integer times, the process of determining the last coefficient group according to the forward scan order may perform a smaller number of transforms A coefficient pixel may be present. In this case, the video decoding apparatus 100 may determine a coefficient group 365 that includes fewer than K number of conversion coefficient pixels. For example, as shown in FIG. 3B, the video decoding apparatus 100 may determine a coefficient group 365 including two transform coefficients.

The video decoding apparatus 100 can obtain information on the

coefficient groups

355 and 360 from the bitstream. Here, the information on the

coefficient groups

355 and 360 includes flag information indicating whether at least one of the conversion coefficients included in the

coefficient groups

355 and 360 is an effective conversion coefficient or only conversion coefficients whose

coefficient groups

355 and 360 are 0 Group flag information).

On the other hand, if the coefficient group including only one transform coefficient is determined, the video decoding apparatus 100 does not acquire information (for example, effective coefficient group flag information) about the coefficient group from the bitstream, Information about the coefficient can be obtained.

The video decoding apparatus 100 generates a context for binary arithmetic decoding information on the current coefficient group on the basis of the information on the coefficient group of the coefficient group scanned earlier than the current coefficient group according to the predetermined scanning order 355 in the reverse direction The model can be determined.

Referring to FIG. 4, the video decoding apparatus 100 may determine a context model of the information about the currently scanned transform coefficient pixel 405 based on the transform coefficient pixels 410. FIG. In FIG. 4, the neighboring transform coefficient pixels 405 may be five pixels existing at a predetermined position on the right side or the lower side of the currently scanned transform coefficient pixel 405. It is easily understood by those skilled in the art that the peripheral transformation coefficient pixels 405 may be n (n is a positive integer) pixels existing at a predetermined position on the right side or the lower side, without limitation thereto.

For example, the video decoding apparatus 100 may compare the context model of the flag information indicating whether the level absolute value of the currently scanned conversion coefficient pixel 405 is greater than 0, Can be determined based on the number of larger coefficient pixels.

The video decoding apparatus 100 further includes a context model of flag information indicating whether the level absolute value of the currently scanned conversion coefficient pixel 405 is greater than 1, Can be determined based on the number of pixels

The video decoding apparatus 100 converts the context model of the flag information indicating whether the level absolute value of the currently scanned conversion coefficient pixel 405 is greater than 2, Can be determined based on the number.

The video decoding apparatus 100 converts the context model of the flag information indicating whether the level value of the currently scanned conversion coefficient pixel 405 is larger than N (N is an integer larger than 2) Can be determined based on the number of coefficient pixels larger than N. [

The video decoding apparatus 100 may determine a parameter for binarizing the residual level absolute value of the currently scanned conversion coefficient pixel 405 based on the sum of the absolute level values of the peripheral conversion coefficient pixels 410. [ At this time, the binarization parameter may be a Rice parameter.

FIG. 5 is a diagram for explaining a process of determining a context model for decoding context-based binary arithmetic decoding information on transform coefficients according to an embodiment.

5, the video decoding apparatus 100 transmits a context model of information on the currently scanned transform coefficient pixel 505 to previously scanned transform coefficient pixels 510 according to a predetermined reverse scan sequence 515, . &Lt; / RTI > As shown in FIG. 5, the transform coefficient pixels 510 may be five pixels previously scanned according to a predetermined reverse echo scan order 515 than the currently scanned transform coefficient pixel 505. Those skilled in the art will readily understand that the transform coefficient pixels 505 may be n (n is a positive integer) pixels previously scanned in accordance with a given reverse echo scan order 515 . As shown in FIG. 5, the predetermined reverse scan order 515 may be a reverse zigzag scan order, but the present invention is not limited thereto. For example, those skilled in the art can understand that the reverse scan order 515 includes a horizontal scan order, a vertical scan order, It can be easily understood. In particular, the predetermined reverse scan order may be determined in one of a plurality of scan orders based on the magnitude of the horizontal direction coordinate value specifying the scan region and the vertical direction coordinate value.

For example, the video decoding apparatus 100 may compare the context model of the flag information, which indicates whether the level absolute value of the currently scanned conversion factor pixel 505 is greater than 0, Can be determined based on the number of large coefficient pixels.

The video decoding apparatus 100 further includes a context model of flag information indicating whether the level absolute value of the currently scanned conversion coefficient pixel 505 is greater than 1, As shown in FIG.

The video decoding apparatus 100 converts the context model of the flag information indicating whether the level absolute value of the currently scanned conversion coefficient pixel 505 is larger than 2, Can be determined based on the number.

The video decoding apparatus 100 transmits a context model of flag information indicating whether the level absolute value of the currently scanned conversion coefficient pixel 505 is larger than N (N is an integer larger than 2) The value can be determined based on the number of coefficient pixels larger than N. [

The video decoding apparatus 100 may determine a parameter for binarizing the residual level absolute value of the currently scanned transform coefficient pixel 505 based on the sum of the absolute value levels of the neighboring transform coefficient pixels 510. [ At this time, the binarization parameter may be a Rice parameter.

FIG. 6A is a diagram for explaining a zigzag scanning order for scanning information on effective conversion coefficients in a block according to an exemplary embodiment. Referring to FIG.

Referring to FIG. 6A, the video decoding apparatus 100 scans the information on the transform coefficient of the current block 600 from the transform coefficient pixel of the lower right end of the current block 600 according to a zigzag scan sequence 605, You can scan up to the conversion factor pixel at the top.

Specifically, in accordance with the zigzag scan sequence 605, the video decoding apparatus 100 scans the lower-left conversion coefficient pixel 610, then scans the left pixel 615 of the pixel 610, The pixel 620 positioned in the diagonal direction of the upper right corner is scanned. The video decoding apparatus 100 scans the pixel 625 adjacent to the upper side of the pixel 620. [ The video decoding apparatus 100 scans the pixels 630 located in the diagonal direction of the lower left corner of the pixel. The video decoding apparatus 100 scans the pixel 635 located on the left of the pixel adjacent to the boundary of the current block 600 among the pixels 630. [ In a similar manner, the video decoding apparatus 100 may scan information on the remaining transform coefficient pixels according to the zigzag scan sequence 605. [

Meanwhile, since the zigzag scan sequence 605 according to an exemplary embodiment of the present invention scans the left directional pixel 615 located in the horizontal direction immediately after the pixel 610 is scanned, the zigzag scan sequence 605 is referred to as a horizontal priority zigzag sequence Can be called.

FIG. 6B is a diagram for explaining a zigzag scanning order for scanning information on intra-block transform coefficients according to another embodiment.

6B, the video decoding apparatus 100 scans the information on the transform coefficient of the current block 600 from the transform coefficient pixel of the lower right end of the current block 600 according to the zigzag scan sequence 635, You can scan up to the conversion factor pixel at the top.

Specifically, in the zigzag scan order 635, the video decoding apparatus 100 scans the upper right pixel 650 of the pixel 645 after scanning the lower right conversion coefficient pixel 645, And then scans the pixel 655 located in the lower left diagonal direction. The video decoding apparatus 100 scans a pixel 660 adjacent to the left side of the pixel 655. [ The video decoding apparatus 100 scans the pixels 665 positioned in the diagonal direction of the upper right corner of the pixel. The video decoding apparatus 100 scans the pixel 670 located above the pixel of the pixels 665 adjacent to the boundary of the current block 500. [ In a similar manner, the video decoding apparatus 100 may scan information on the remaining transform coefficient pixels according to the zigzag scan sequence 605. [

Meanwhile, the zigzag scan sequence 605 according to an exemplary embodiment of the present invention scans an upward direction pixel 650 positioned in a vertical direction immediately after the scan of the pixel 645, so that the zigzag scan sequence 605 is referred to as a vertical priority zigzag sequence Can be called.

7A, the video decoding apparatus 100 scans information on the transform coefficient of the current block 700 from the transform coefficient pixel of the lower right end of the current block 700 according to the horizontal scan order 705, You can scan up to the conversion factor pixel at the top.

Specifically, in the horizontal scanning order 705, the video decoding apparatus 100 sequentially scans the pixels 715 positioned in the horizontal direction, which is the horizontal direction, after scanning the conversion coefficient pixel 710 at the lower right end And scans the pixels of the pixels 715 adjacent to the left boundary of the current block 700 and then scans the rightmost pixel 720 of the immediately above row. The video decoding apparatus 100 scans the pixels 725 located in the leftward direction in the horizontal direction in the same manner as the pixels of the previous row 715 are scanned. In a similar manner, the video decoding apparatus 100 may scan information on the remaining transform coefficient pixels according to the horizontal scan order 605. [

Referring to FIG. 7B, the video decoding apparatus 100 scans information on the transform coefficient of the current block 700 from the transform coefficient pixel of the lower right end of the current block 700 according to the vertical scanning order 730, You can scan up to the conversion factor pixel at the top.

Specifically, according to the vertical scanning order 730, the video decoding apparatus 100 sequentially scans the pixels 740 located in the vertical direction, which is the vertical direction, after scanning the conversion coefficient pixel 735 at the lower right end , A pixel of the pixels 740 that is adjacent to the upper boundary of the current block 700 is scanned, and then the lowermost pixel 745 of the column immediately to the left is scanned. The video decoding apparatus 100 scans the pixels 750 positioned in the vertical direction in the same manner as the pixels 740 of the previous row are scanned. In a similar manner, the video decoding apparatus 100 may scan information about the remaining transform coefficient pixels according to the vertical scan order 730. [

8, the video decoding apparatus 100 reads the transform coefficients of the current block 800 from the transform coefficient pixels of the lower right end of the current block 800 according to the diagonal scan order 805 to scan information on the transform coefficients of the current block 800, You can scan up to the conversion factor pixel at the top.

Specifically, in the diagonal scan order 805, the video decoding apparatus 100 scans the upper right pixel 810 of the pixel 810 after scanning the lower right conversion coefficient pixel 810, And then scans the pixel 820 located in the lower left diagonal direction. The video decoding apparatus 100 scans the pixel 825 adjacent to the upper side of the pixel 815. [ The video decoding apparatus 100 scans the pixels 830 positioned in the diagonal direction of the lower left end of the pixel 825. [ In a similar manner, the video decoding apparatus 100 may scan information on the remaining transform coefficient pixels according to the diagonal scan sequence 805. [

6A to 8, various scan sequences for scanning information on effective conversion coefficients in a block have been described. The scan orders described with reference to FIGS. 6A to 8 can be easily understood in a reverse scan order, or a forward scan order in which a person skilled in the art scans in the reverse order of the reverse scan order.

9A to 9C, the video decoding apparatus 100 may scan the syntax element information about the transform coefficients to recover the transform coefficients, and may decode the transform coefficients based on the scanned syntax element information.

First, the video decoding apparatus 100 may obtain syntax element information scan_region_x and scan_region_y indicating coordinates for specifying a quadrangular scan region from a bitstream. At this time, the syntax element information scan_region_x may indicate the value of the horizontal direction (x-axis direction) coordinate of the effective transformation coefficient located at the rightmost position in the current block with reference to the upper left corner coordinate of the current block, and the syntax element information scan_region_y indicates (Y-axis direction) coordinate of the effective transformation coefficient located at the lowermost position in the current block with reference to the upper left corner coordinate of the block. The video decoding apparatus 100 can determine the coordinates srX and srY for specifying the scan area based on the syntax element information scan_region_x and scan_region_y.

The video decoding apparatus 100 can determine the scan order (ScanOrder (srX + 1, srY + 1)) of the intra-scan transform coefficients determined according to the scan order based on the coordinates srX and srY for specifying the scan region .

The video decoding apparatus 100 may determine index information (lastSet) indicating a coefficient group to be scanned last in a forward scan order based on the coordinates srX and srY for specifying a scan region. That is, the video decoding apparatus 100 performs an operation (" 4 ") for bit-shifting the value of (srX + 1) * (srY + The index information (lastSet) of the coefficient group to be scanned can be determined. That is, the output value of the right shifting operation by 4 can be the same as the quotient determined by dividing by 16. That is, since the video decoding apparatus 100 determines one coefficient group for every 16 transform coefficients, if the total transform coefficient scanned in the scan region is divided by 16, the number of total coefficient groups (or the end of the forward scan order) A value obtained by adding 1 to an index value indicating a group of scanned coefficients) can be determined.

The video decoding apparatus 100 determines the position (lastScanPos) of the last scanned coefficient in the forward scan order based on the coordinates srX and srY for specifying the scan region and sets the position Pos of the current transformation coefficient as the forward scan The position of the last scanned coefficient in the sequence (lastScanPos) can be determined.

The video decoding apparatus 100 may initialize i to last set, reduce i by 1 if i is greater than 0, and perform the operations included in the loop statement (for statement) 905. [ The video decoding apparatus 100 may perform the operations included in the for-statement (for statement) 905 until the value becomes less than zero. In this case, i may be an index indicating a coefficient group. That is, the video decoding apparatus 100 may perform an operation on one coefficient group every time the operation included in the loop statement (for statement) 905 is performed.

The video decoding apparatus 100 can determine the setPos by performing an operation (i << 4) of multiplying i by 16. setPos can represent the index information of the transform coefficient located at the first position of the transform group.

The video decoding apparatus 100 determines n as 15 (lastScanPos-setPos) obtained by subtracting setPos from lastScanPos when i is the last coefficient group (i == lastSet) If greater than or equal to, i can be reduced by one and the operations contained in the loop statement (for statement) 910 can be performed. The video decoding apparatus 100 can perform the operation (sig_flag related operation) included in the forbidden statement (for statement) 910 until the value becomes less than zero. In this case, n may be index information indicating the position of the transform coefficient in the coefficient group according to the forward scan order.

For example, if the total number of transform coefficients included in the scan area is not an integer multiple of 16, the value obtained by subtracting setPos from lastScanPos for the last scanned coefficient group (i = last set) according to the forward scan is greater than zero Or equal to or less than 15, and the value thereof is determined as n, and a loop statement (for statement) 910 can be performed. The video decoding apparatus 100 may determine the position (blkpos) of the current transform coefficient as a value obtained by adding n to the index information (setPos) indicating the position of the first coefficient of the current coefficient group in the ScanOrder array. The ScanOrder array may be an array indicating the position of the transform coefficients according to the forward scan order.

The video decoding apparatus 100 can determine the value sx of the coordinate in the horizontal direction (x-axis direction) currently scanned based on the position (blkpos) of the current transform coefficient and the width of the scan area. In addition, the video decoding apparatus 100 can determine the value sy of the coordinate in the vertical direction (y-axis direction) based on the position (blkpos) of the transform coefficient to be decoded and the width (log2width) of the scan area.

The video decoding apparatus 100 determines whether sx is 0, sy is srY, is_last_y is 0 (sx == 0 && sy == srY && is_last_y == 0), sy is 0, sx is srX, is_last_x 0), the video decoding apparatus 100 does not acquire the effective conversion coefficient flag sig_flag (sig_flag [blkpos]) for the current conversion coefficient from the bitstream, but does not acquire the current conversion coefficient flag sig_flag (sig_flag [blkpos] The value of sig_flag for the conversion coefficient can be determined as 1. [ Here, is_last_x may be a value indicating whether there is an effective transform coefficient whose absolute value is greater than 0 among the transform coefficients scanned before the current transform coefficient among the transform coefficients included in the lowermost row in the scan area. is_last_y may be a value indicating whether there is an effective transform coefficient whose absolute value is greater than 0 among the transform coefficients included in the rightmost column in the scan area and scanned before the current transform coefficient.

The video decoding apparatus 100 determines whether sy is 0, sy is srY, is_last_y is 0 (sx == 0 && sy == srY && is_last_y == 0), sy is 0, sx is srX, is_last_x is 0 , Sig_flag (sig_flag [blkpos]) for the transform coefficient to be currently decoded from the bit stream can be obtained, if not (sy == 0 && sx == srX && is_last_x == 0).

The video decoding apparatus 100 sets is_last_x to 1 if the coordinate value sx in the x-axis direction of the current transform coefficient is equal to srX (sx == srX) when the effective transform coefficient flag sig_flag of the current transform coefficient is 1 , And if the coordinate value sy in the y-axis direction of the current transformation coefficient is equal to srY (sy == srY), then is_last_y can be set to 1.

In addition, the video decoding apparatus 100 may determine lastSigScanPos to be n if lastSigScanPos is -1 (i.e., initial value). That is, since the index n indicating the position where the first effective transform coefficient of the coefficient group exists in the backward scan order is determined by lastSigScanPos, lastSigScanPos is an index indicating the position where the last valid transform coefficient exists in the forward scan order coefficient group Information. On the other hand, the video decoding apparatus 100 can determine firstSigScanPos as n. If the effective conversion coefficient flag sig_flag of the current conversion coefficient is 1, the value of firstSigScanPos is updated to n, which is the index information indicating the position of the current conversion coefficient, so that the operation is performed on the conversion coefficients included in the specific coefficient group i The firstSigScanPos may be index information indicating a position where the first effective transform coefficient in the forward scan order coefficient group exists.

The video decoding apparatus 100 increases cnt_nz by one. That is, cnt_nz indicating the number of coefficients having a non-zero value in the current block (or scan area) is updated each time the current transform coefficient is an effective transform coefficient. In addition, the video decoding apparatus 100 increases cg_nz [i], which indicates the number of coefficients having non-zero values in the current coefficient group i, by one. That is, cg_nz [i] indicating the number of coefficients having a non-zero value in the current coefficient group i is updated every time the current transform coefficient is an effective transform coefficient.

The video decoding apparatus 100 determines n as 15 (lastScanPos-setPos) obtained by subtracting setPos from lastScanPos when i is the last coefficient group (i == lastSet) If it is greater than or equal to i, i can be reduced by 1 and the operations included in the loop statement (for statement) 915 can be performed. The video decoding apparatus 100 may perform the operations (coeff_abs_level_greater1_flag and coeff_abs_level_greater2_flag related operations) included in the forbidden statement (for statement) 915 until the value becomes less than zero.

The video decoding apparatus 100 may determine the position (blkpos) of the current transform coefficient as a value obtained by adding n to the index information (setPos) indicating the position of the first coefficient of the current coefficient group in the ScanOrder array.

The video decoding apparatus 100 can obtain the absolute value abs_coef for the current transform coefficient based on the current transform coefficient information gt0 flag, gt1 flag, gt2 flag, remainining_abolute value level.

When the effective conversion coefficient flag (sig_flag [blkpos]) of the current conversion coefficient is 1, the video decoding apparatus 100 determines that the absolute value of the conversion coefficient among the conversion coefficients included in the previously scanned coefficient groups is a conversion The number of coefficients cnt_g1 and the number c1 of transform coefficients obtained from the bitstream of previously scanned transform coefficients obtained from coeff_abs_level_greater1_flag obtained from coeff_abs_level_greater_flag from the bit stream among the transform coefficients having an absolute value larger than 1 The video decoding apparatus 100 can obtain coeff_abs_level_greater1_flag (coeff_abs_level_greater1_flag [blkpos]) for the current transform coefficient from the bit stream. coeff_abs_level_greater1_flag may be a flag indicating whether the absolute value of the current transform coefficient is greater than one. The video decoding apparatus 100 can determine the flag gt1_flag (gt1flag [blkpos]) of the current transform coefficient based on coeff_abs_level_greater1_flag obtained from the bitstream.

The video decoding apparatus 100 can increase c1 by 1 when the value of the flag gt1_flag of the current transform coefficient is 1. If the flag gt1_flag of the current transform coefficient is 1, the value of c1 is increased by 1 and the value of c1 is updated. Therefore, when performing the loop operation (for statement) () on the next transform coefficients, The number of transform coefficients obtained by obtaining coeff_abs_level_greater1_flag from the bitstream among the previously scanned transform coefficients in the group.

When the effective conversion coefficient flag (sig_flag [blkpos]) of the current conversion coefficient is 1, the video decoding apparatus 100 determines that the absolute value of the conversion coefficient among the conversion coefficients in the previously scanned coefficient groups is greater than 2 The number cnt_g2 of the coefficients and the number c2 of transform coefficients obtained from the previously scanned bit stream in coeff_abs_level_greater2_flag is smaller than the sum of the coefficients cnt_g2 and cnt2 of the transform coefficients that can obtain coeff_abs_level_greater_flag from the bit stream among the transform coefficients having an absolute value of the coefficient greater than 2 If it is smaller than the maximum number num_gt2, the video decoding apparatus 100 can obtain coeff_abs_level_greater2_flag for the current transform coefficient from the bitstream. coeff_abs_level_greater2_flag may be a flag indicating whether the absolute value of the current transform coefficient is greater than two. The video decoding apparatus 100 can determine the flag gt2_flag of the current transform coefficient based on coeff_abs_level_greater2_flag obtained from the bitstream.

The video decoding apparatus 100 can increase the number c2 of the current gt2 flags by 1 when the value of the flag gt2_flag of the current conversion coefficient is 1. When the flag gt2_flag of the current transform coefficient is 1, the value of c2 is increased by 1 and the value of c2 is updated. Therefore, when performing the loop operation (for statement) () on the next transform coefficients, The number of transform coefficients obtained by obtaining coeff_abs_level_greater1_flag from the bitstream among the previously scanned transform coefficients in the group.

In addition, the video decoding apparatus 100 may determine that escapeDataPresent is set to 1. The escapeDataPresent may be information indicating that there is additional information (e.g., residual level absolute value information coeff_abs_level_remaining) to determine the value of the transform coefficient in the current transform group.

When the effective conversion coefficient flag (sig_flag [blkpos]) of the current conversion coefficient is 1, the video decoding apparatus 100 determines that the absolute value of the conversion coefficient among the conversion coefficients in the previously scanned coefficient groups is greater than 2 The number cnt_g2 of the coefficients and the number c2 of transform coefficients obtained from the previously scanned bit stream in coeff_abs_level_greater2_flag is smaller than the sum of the coefficients cnt_g2 and cnt2 of the transform coefficients that can obtain coeff_abs_level_greater_flag from the bit stream among the transform coefficients having an absolute value of the coefficient greater than 2 If it is not smaller than the maximum number num_gt2, the video decoding apparatus 100 can determine the escapeDataPresent to be 1. [

The video decoding apparatus 100 decodes the number of transform coefficients cnt_g1 having an absolute value of the transform coefficient among the transform coefficients included in the previously scanned coefficient groups greater than 1, When the sum of the number of transform coefficients c1 obtained from coeff_abs_level_greater1_flag is not smaller than num_gt1 which is the maximum number of transform coefficients capable of obtaining coeff_abs_level_greater_flag from the bit stream among the transform coefficients having an absolute value larger than 1, 100) can determine escapeDataPresent to be 1.

The video decoding apparatus 100 determines n as a value obtained by subtracting setPos from lastScanPos (lastScanPos-setPos) when i is the last coefficient group when escapeDataPresent is 1, and n is 15 And if n is greater than or equal to 0, i may be decreased by 1 and the operations contained in the loop statement (for statement) 920 may be performed. The video decoding apparatus 100 may perform an operation (an operation related to coeff_abs_level_reamining) included in the forbidden statement (for statement) 920 until the value becomes less than zero.

The video decoding apparatus 100 can determine the base level when the absolute value of the current transform coefficient is larger than 1 (sig_flag [blkpos]). Current transform coefficient in current coefficient group number of transform coefficients having an absolute value larger than 1 among transform coefficients scanned before cnt_gt1 coeff_abs_level_greater_flag can be obtained from a bit stream among transform coefficients having an absolute value larger than 2 Cnt_gt2 where the absolute value of the transform coefficients of the transform coefficients scanned prior to the current transform coefficient in the current coefficient group is greater than 2, when the absolute value of the transform coefficient is smaller than 2 The video decoding apparatus 100 can determine the base level to be 3 when the bit rate is smaller than the maximum number num_gt2 of conversion coefficients capable of obtaining coeff_abs_level_greater_flag from the bitstream. If cnt_gt1 is smaller than num_gt1 that can be obtained from the bitstream, the video decoding apparatus 100 can determine the base level to be 2 if cnt_gt2 is smaller than num_gt2. If cnt_gt1 is not smaller than num_gt1, the video decoding apparatus 100 can determine the base level to be 1.

The video decoding apparatus 100 can determine the absolute value level abs_coef of the current transform coefficient by adding 1 to the value obtained by adding the value of gt1flag and the value of gt2flag to the current transform coefficient. The video decoding apparatus 100 can obtain the residual absolute value level coeff_abs_level_remaining for the current transform coefficient from the bitstream if the absolute value of the current transform coefficient has the same value as the base level (abs_coef [blkpos] == base_level) . The video decoding apparatus 100 may determine the absolute value level abs_coef for the current transform coefficient by adding the residual absolute value level level_remaining to the current transform coefficient to abs_coef.

The video decoding apparatus 100 can increase cnt_gt2 by 1 if the absolute value level abs_coef for the current transform coefficient is greater than 2. Also, if the absolute value level abs_coef for the current transform coefficient is greater than 1, the video decoding apparatus 100 may increase cnt_gt1 by one.

If escapeDataPresent is 0, if i represents the last coefficient group (i == lastSet), n is determined by subtracting setPos from lastScanPos (lastScanPos-setPos), otherwise n is determined to be 15, If it is greater than or equal to i, then i may be reduced by one and the operations contained in the loop statement (for statement) 925 may be performed. The video decoding apparatus 100 may perform the operation (abs_coef related operation) contained in the forbidden statement (for statement) 925 until the value becomes less than zero. The index information (setPos) indicating the position of the first coefficient of the current coefficient group in the ScanOrder array can be determined by adding n to the index information (setPos).

The video decoding apparatus 100 can increase the cnt_gt2 by 1 if the effective conversion coefficient flag for the current conversion coefficient is 1 and abs_coef, which is an absolute value for the current conversion coefficient, is greater than or equal to 2. When the effective conversion coefficient flag for the current conversion coefficient is 1, if the absolute value abs_coef for the current conversion coefficient is greater than or equal to 1, cnt_gt1 can be increased by one.

When the difference between the position lastSigScanPos of the last effective transform coefficient in the current coefficient group i scanned in the forward scan order and the position firstSigScanPos of the first effective transform coefficient is greater than 3, the video decoding apparatus 100 determines that at least one The signHidden value (signHidden [i]) indicating that the sign of the sign is hidden is set to 1. If the difference between the position lastSigScanPos of the last effective transform coefficient in the current coefficient group scanned in the forward scan order and the position firstSigScanPos of the first effective transform coefficient is not greater than 3, the video decoding apparatus 100 determines that at least one The signHidden value (signHidden [i]) indicating that the sign of the signHidden is hidden can be determined as 0.

The video decoding apparatus 100 may initialize i to 0 and increment i by 1 if i is less than or equal to lateSet and perform the operations contained in the loop statement (for statement) 930. [ The video decoding apparatus 100 can perform the operations included in the forbidden statement (for statement) 930 until i becomes larger than lateSet. In this case, i may be an index indicating a coefficient group. That is, the video decoding apparatus 100 may perform an operation for one coefficient group every time the operation included in the loop statement (for statement) 930 is performed.

If rsp (residual sign prediction) is applied (rsp_apply),

The video decoding apparatus 100 determines n as 15 (lastScanPos-setPos) obtained by subtracting setPos from lastScanPos when i is the last coefficient group (i == lastSet) If it is greater than or equal to i, then i can be decreased by 1 and the operation contained in the loop statement (for statement) 935 can be performed. The video decoding apparatus 100 may perform the operations included in the forbidden statement (for statement) 935 until the value is less than zero.

The video decoding apparatus 100 may determine the position (blkpos) of the currently decoded transform coefficient as a value obtained by adding n to the index information setPos indicating the position of the first coefficient of the current coefficient group in the ScanOrder array according to the forward scan order .

If the position blkpos of the transform coefficient to be currently decoded is not rsp_pos, the video decoding apparatus 100 outputs information (sign [blkpos]) about the sign of the transform coefficient to be currently decoded if the sign of the transform coefficient is the position hidden_pos of the hidden transform coefficient, Can be determined by information hidden_sign on the sign of the hidden transform coefficient.

If the sign of the transform coefficient is not the position hidden_pos of the hidden transform coefficient, the video decoding apparatus 100 can obtain the information (sign [blkpos]) about the sign of the transform coefficient currently being decoded from the bit stream.

The video decoding apparatus 100 can obtain the information (sign_rsp [blkpos]) regarding the rsp code of the transform coefficient currently being decoded from the bitstream if the position blkpos of the transform coefficient to be currently decoded is rsp_pos.

If rsp is not applied, the video decoding apparatus 100 determines n to be a value obtained by subtracting setPos from lastScanPos (lastScanPos-setPos) if i is the last coefficient group (i == lastSet) And if n is greater than or equal to zero, i may be decremented by one and the operations contained in the loop statement (for statement) 940 may be performed. The video decoding apparatus 100 may perform the operation included in the forbidden statement (for statement) 940 until the value is less than zero.

The video decoding apparatus 100 may determine the position (blkpos) of the current transform coefficient as a value obtained by adding n to the index information setPos indicating the position of the first coefficient of the current coefficient group in the ScanOrder array according to the forward scan order.

If the value of the flag sign_data_hiding_enabled_flag indicating whether the value of the effective conversion coefficient flag of the current conversion coefficient is 1 and activating the hiding of the sign data is 0 or if there is no code hidden for the current group (! SignHidden [i]), Information (sign [blkpos]) concerning the sign of the current transform coefficient can be obtained from the bit stream when the position of the current transform coefficient in the current scan group is not the position of the first effective transform coefficient in the scan order.

9D to 9F, the video decoding apparatus 100 may scan the syntax element information about the transform coefficients to recover the transform coefficients, and may decode the transform coefficients based on the scanned syntax element information.

First, the video decoding apparatus 100 may obtain syntax element information last_sig_coeff_x and last_sig_coeff_y indicating coordinates for specifying a scan area from a bitstream. At this time, the syntax element information last_sig_coeff_x can represent the value of the horizontal direction (x-axis direction) coordinate of the effective transformation coefficient located last in the forward scan order based on the upper left corner coordinate of the current block, and the syntax element information last_sig_coeff_y may indicate the value of the vertical direction (y-axis direction) coordinate of the effective transformation coefficient positioned at the end in the current block according to the forward scan order based on the upper left corner coordinate of the current block. The video decoding apparatus 100 may determine the coordinates LastSigcoeffX and LastSigCoeffY for specifying the scan area based on the syntax element information last_sig_coeff_x and last_sig_coeff_y.

The video decoding apparatus 100 may initialize the position lastScanPos of the effective transformation coefficient located last in the forward scan order in the subblock to 16. The video decoding apparatus 100 may initialize the lastSubBlock indicating the sub-block in which the last valid transform coefficient is located according to the forward scan order in the sub-block. At this time, the initialized value may indicate the last sub-block of the current block scanned according to the forward scan order. That is, the lastSubBlock may be initialized to a value indicating the last sub-block among the sub-blocks scanned in the forward scan order based on the height and width of the current block.

The video decoding apparatus 100 performs an operation in the Do-while loop statement 950 when the position xC in the horizontal direction of the current coefficient is not LastSigcoeffX or the position yC in the vertical direction of the current coefficient is not LastSigcoeffY, If LastSigcoeffX and position yC in the vertical direction of the current coefficient is LastSigcoeffY, the operation in the do-while loop statement 950 may no longer be performed.

The video decoding apparatus 100 may determine the lastScanPos to be 16 and reduce the lastSubblock by 1 if lastScanPos is zero. That is, when the scan in one sub-block is completed (lastScanPos is 0) according to the reverse scan order, lastScanPos is initialized to 16 to scan the next sub-block according to the reverse scan order, the lastSubblock can be reduced by one. The video decoding apparatus 100 may scan the transform coefficients in the current subblock lastSubblock according to a reverse scan order while decrementing lastScanPos by one.

The video decoding apparatus 100 can determine the horizontal position xS and the vertical position yS of the current subblock. The video decoding apparatus 100 may determine the position of the current subblock based on the ScanOrder array determined according to a predetermined forward scan order with respect to the current block. That is, the video decoding apparatus 100 can determine the position of the current sub-block based on the height (log2height) and the width (log2width) of the current block, the scan index scanIdx indicating the predetermined scan order, and the value lastSubBlock indicating the current sub- have. Here, xS and yS may be positions of subblocks when treating subblocks as one pixel, rather than positions of actual subblocks. That is, the width and the height of the sub-block may be ignored, and the difference between the sub-block horizontal direction and the vertical direction between adjacent sub-blocks may be one.

In addition, the video decoding apparatus 100 can determine the horizontal direction position xC and the vertical direction position yC of the current transform coefficient based on the ScanOrder array determined in accordance with a predetermined forward scan order for the current subblock. That is, the video decoding apparatus 100 determines the height (log ₂ 4 = 2) and the width (log ₂ 4 = 2) of the current subblock, the scan index scanIdx indicating a predetermined scan order, ) And a value lastScanPos indicating the position of the current transform coefficient in the current subblock, the position (xC, yC) of the current transform coefficient can be determined.

The video decoding apparatus 100 will no longer perform the operation in the do-while loop statement 950 when the vertical direction position yC of the current transform coefficient is LastSigcoeffY, lastScanPos may be index information indicating the position of the last valid transform coefficient in the subblock including the last valid transform coefficient in the current block scanned in the forward scan order, and lastSubBlock may be index information indicating the position of the last valid transform coefficient in the current block And may be index information indicating a block.

The video decoding apparatus 100 may initialize i to lastSubBlock, reduce i by 1 if i is greater than 0, and perform the operations contained in the loop statement (for statement) 960. [ The video decoding apparatus 100 may perform the operation included in the forbidden statement (for statement) 960 until the value is less than zero. In this case, i may be an index indicating a coefficient group. That is, the video decoding apparatus 100 may perform an operation on one subblock each time the operation included in the loop statement (for statement) 960 is performed.

The video decoding apparatus 100 can determine the horizontal position xS and the vertical position yS of the current subblock.

The video decoding apparatus 100 refers to a sub-block having a value smaller than a value (lastSubBlock) indicating a sub-block in which the current effective transform coefficient is located, indicating a current sub-block, or a sub-block including a DC coefficient Quot; coded_sub_block_flag [xS] [yS] for the current subblock i can be obtained when the subblock has a value larger than the value (0). coded_sub_block_flag [xS] [yS] may be flag information indicating whether the coded_sub_block_flag [xS] [yS] includes at least one valid conversion coefficient in the current subblock i.

The video decoding apparatus 100 initializes n to lastScanPos-1 if the current subblock is the lastSubBlock including the last valid transform coefficient, otherwise initializes to 15 and if n is greater than or equal to 0 In this case, n can be reduced by 1, and the operation included in the loop (for statement) () can be performed. The video decoding apparatus 100 can perform the operations included in the loop statement (for statement) 960 until n becomes less than 0. Here, n is an index indicating the position of the current transform coefficient in the sub-block Lt; / RTI > That is, the video decoding apparatus 100 can perform an operation on one coefficient group every time the operation included in the loop statement (for statement) () is performed once. That is, the video decoding apparatus 100 may perform an operation (operation related to sig_coeff_flag) for one subblock each time the operation included in the loop statement (for statement) 960 is performed.

The video decoding apparatus 100 can determine the positions xC and yC of the current transform coefficient n.

When the coded_sub_block_flag [xS] [yS] for the current sub-block is 1, n is greater than 0 or inferSbDcSigCoeffFlag is 0, the video decoding apparatus 100 sets the flag sig_coeff_flag [xC] [yC] Can be obtained from the stream. sig_coeff_flag [xC] [yC] may be a flag indicating whether the current conversion coefficient is an effective conversion coefficient.

If the value of sig_coeff_flag [xC] [yC] is 1, inferSbDcSigCoeffFlag can be determined to be 0.

The video decoding apparatus 100 initializes the value of the firstScanPos position of the transform coefficient scanned first in the current subblock according to the forward scan order and outputs the position of the transform coefficient scanned last in the current subblock according to the forward scan order You can initialize the value of lastSigScanPos. The video decoding apparatus 100 may initialize the value of numGreater1Flag indicating the number of Greater1Flag and initialize the value of the last position lastGreater1ScanPos at which Greater1Flag is acquired according to the forward scanning order.

The video decoding apparatus 100 can initialize cg_nz [i] indicating the number of non-zero transform coefficients in subblock i.

The video decoding apparatus 100 initializes n to 15. If n is greater than or equal to 0, n can be decreased by 1, and the operation within the loop statement (for statement) 965 can be performed until n is less than zero.

The video decoding apparatus 100 acquires coeff_level_greater1_flag [n] for the current transform coefficient n if numGreater1Flag is smaller than 8 when the effective transform coefficient flag sig_coeff_flag for the current transform coefficient is 1, and increases the value of numGreater1Flag by 1 . coeff_level_greater1_flag [n] may be flag information indicating whether the absolute value of the level of the conversion coefficient n is greater than one. The video decoding apparatus 100 can determine Greater1Flag [n] based on coeff_level_greater1_flag [n].

If the value of coeff_abs_level_greater_flag for the current transform coefficient is 1 and the value of lastreater1ScanPos is the initial value, the video decoding apparatus 100 can determine the lastGreater1ScanPos as the current transform coefficient position n in the current subblock. Therefore, lastGreater1ScanPos may be index information indicating the position of a coefficient having a value of coeff_abs_level_greater_flag positioned last in the current subblock according to the forward scan order. Otherwise (not the case where the value of coeff_abs_level_greater1_flag for the current transform coefficient is 1 and the value of lastreater1ScanPos is the initial value), and if coeff_abs_level_greater1_flag is 1, escapeDataPresent can be set to 1.

The video decoding apparatus 100 can determine escapeDataPresent to be 1 if numGreater1Flag is not smaller than 8.

The video decoding apparatus 100 may determine lastSigScanPos to be the current position n of the intra-subblock transform coefficient when the lastSigScanPos indicating the position of the effective transform coefficient located at the end in the current subblock has an initial value according to the forward scan order .

The video decoding apparatus 100 may determine firstSigScanPos, which indicates the position of the effective transform coefficient located first in the current subblock, as the current transform coefficient position n in the current subblock according to the forward scan order. If the effective conversion coefficient flag sig_coeff_flag [xC] [yC] of the current conversion coefficient is 1, the value of firstSigScanPos continues to be updated to n, which is the index information indicating the position of the current transform coefficient in the current subblock. The firstSigScanPos may be the index information indicating the position where the first effective transform coefficient exists in the subblock in the forward scan order.

The video decoding apparatus 100 may determine the sigHidden value to be 1 if the difference between lastSigScanPos and firstSigScanPos is greater than 3 and may determine the sigHidden value to be 0 if the difference between lastSigScanPos and firstSigScanPos is not greater than 3. In this case, sigHidden may be a value indicating that the sign of at least one transform coefficient is hidden for the current subblock.

If coeff_abs_level_greater1_flag of the coeff_abs_level_greater1_flag (Greater1Flag) for the transform coefficient obtained from the scanned bitstream according to the forward scan order is not the initial value (i.e., at least one Greater1Flag from the bitstream) Is obtained in the current subblock), the video decoding apparatus 100 can obtain the flag coeff_abs_level_greater2_flag [lastGreater1ScanPos] for the transform coefficient of the lastGreater1ScanPos position from the bitstream. coeff_abs_level_greater2_flag may be a flag indicating whether the absolute value of the transform coefficient is greater than two. If the value of the flag coeff_abs_level_greater2_flag [lastGreater1ScanPos] for the conversion coefficient at the lastGreater1ScanPos position is 1, the video decoding apparatus 100 can determine the escapeDataPresent to be 1. [ The video decoding apparatus 100 can determine Greater2Flag [n] based on coeff_level_greater2_flag [n].

The video decoding apparatus 100 can initialize numSigCoeff. In this case, numSigCoeff may mean the number of effective transform coefficients among the transform coefficients scanned before the current transform coefficient according to the reverse scan order.

The video decoding apparatus 100 initializes n to 15. If n is greater than or equal to 0, n is decreased by 1 and an operation within the for 970 is performed. If n is smaller than 0, the for decoding 970 ) My action may no longer be performed. The video decoding apparatus 100 may perform an operation of scanning information on the current intra-block transform coefficients in a backward scan order.

The video decoding apparatus 100 can determine the position xC, yC of the current transform coefficient based on the position n of the current transform coefficient in the current subblock.

When the value of the effective conversion coefficient flag sig_coeff_flag [xC] [yC] related to the current conversion coefficient is 1, the video decoding apparatus 100 sets the value of the flag coeff_abs_level_greater1_flag related to the current conversion coefficient, the value of the flag coeff_abs_level_greater2_flag You can determine baseLevel by adding the sum to the sum.

If numSigCoeff is less than 8 and the position n of the current transform coefficient is lastGreater1ScanPos, if the base level is 3, the video decoding apparatus 100 extracts the residual level value information coeff_abs_level_remaining [n] for the current transform coefficient n from the bitstream Can be obtained.

If numSigCoeff is less than 8 and the current position n of the transform coefficient is not lastGreater1ScanPos, if the base level is 2, the video decoding apparatus 100 extracts residual level value information coeff_abs_level_remaining [n Can be obtained. If numSigCoeff is greater than 8, if the base level is 1, the video decoding apparatus 100 may obtain the residual level value information coeff_abs_level_remaining [n] for the current transform coefficient n from the bitstream.

The video decoding apparatus 100 obtains the TransCoeffLevel [x0] [y0] [cIdx] [xC] [yC], which is the level value of the current transform coefficient in the current block, by summing the base level for the current transform coefficient and the residual level value for the current transform coefficient. Can be determined. Here, cIdx may be an index indicating a color component.

If i increases from 0 to 1, it can perform the operations contained in the forbidden statement (for statement) 975 until it becomes less than or equal to the value of lastSubBlock. In this case, i may be an index indicating a sub-block. That is, the video decoding apparatus 100 can perform an operation for one coefficient group every time the syntax in the for statement 975 is performed once.

If the flag coded_sub_block_flag [xS] [yS] for the current subblock i is 1 and rsp is applied (rsp_apply), the video decoding apparatus 100 determines n to be 15, and if n is greater than 0 If it is the same, the for statement (980) operation can be performed again if n is greater than or equal to 0 after performing the operation in the for statement (980) and decrementing n by 1. If n is less than 0, the operation in the for statement (980) may not be performed any more.

The video decoding apparatus 100 can determine the horizontal position and the vertical position xC and yC of the current transform coefficient corresponding to the position n of the current transform coefficient in the current subblock. The video decoding apparatus 100 can determine the position (blkpos) of the current transform coefficient based on xC and yC.

If the position blkpos of the current transform coefficient is not rsp_pos, the video decoding apparatus 100 can determine the sign of the current transform coefficient as the sign hidden_sign of the hidden transform coefficient if the code is the position hidden_pos of the transform coefficient hidden therein.

If not, the video decoding apparatus 100 can obtain the information sign [xC] [yC] concerning the sign of the current transform coefficient from the bitstream, if the code is not the position hidden_pos of the hidden transform coefficient.

The video decoding apparatus 100 can obtain the information sign_rsp [xC] [yC] regarding the rsp code of the current transform coefficient from the bit stream when the current transform coefficient position is rsp_pos.

If rsp is not applied, the video decoding apparatus 100 determines n to be 15. If n is greater than 0, the video decoding apparatus 100 performs the operation in the for statement (985), reduces n by 1, If greater than or equal to, the for statement (985) operation can be performed again, and if n is less than 0, the operation within the for statement (985) may no longer be performed.

If the value of the flag sign_data_hiding_enabled_flag indicating whether the value of the effective conversion coefficient flag sig_coeff_flag [xC] [yC] of the current conversion coefficient is 1 and activating the hiding of the sign data is 0, or if there is no hidden code for the current subblock (! SignHidden If the position of the current transform coefficient in the current sub-block in the forward scan order is not the first effective transform coefficient position firstSigScanPos is 0, the sign information sign [xC] [yC] of the current transform coefficient is calculated from the bit stream Can be obtained.

Hereinafter, a method of determining a data unit usable in the process of decoding a video by the video decoding apparatus 100 according to an embodiment will be described with reference to FIGS. 10 to 23. FIG. The operation of the video encoding apparatus 150 may be similar to or opposite to the various embodiments of the operation of the video decoding apparatus 100 described later.

FIG. 10 illustrates a process in which the video decoding apparatus 100 determines at least one encoding unit by dividing a current encoding unit according to an embodiment.

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

According to an embodiment, the video decoding apparatus 100 may use block type information indicating that the current encoding unit is a square type. For example, the video decoding apparatus 100 can determine whether to divide a square encoding unit according to division type information, vertically divide, horizontally divide, or divide into four encoding units. 10, if the block type information of the current encoding unit 1000 indicates a square shape, the video decoding apparatus 100 may calculate the size of the current encoding unit 1000 according to the division type information indicating that the current block is not divided, (1010b), 1010c (1010d, etc.) based on the division type information indicating the predetermined division method.

Referring to FIG. 10, the video decoding apparatus 100 determines two coding units 1010b obtained by dividing the current coding unit 1000 in the vertical direction based on division type information indicating division in the vertical direction according to an embodiment . The video decoding apparatus 100 can determine two coding units 1010c obtained by dividing the current coding unit 1000 in the horizontal direction based on the division type information indicating that the coding unit is divided in the horizontal direction. The video decoding apparatus 100 can determine four coding units 1010d obtained by dividing the current coding unit 1000 in the vertical direction and the horizontal direction based on the division type information indicating that the coding unit 1000 is divided in the vertical direction and the horizontal direction. However, the division type in which the square coding unit can be divided should not be limited to the above-mentioned form, but may include various forms in which the division type information can be represented. The predetermined divisional form in which the square encoding unit is divided will be described in detail by way of various embodiments below.

FIG. 11 illustrates a process in which the video decoding apparatus 100 determines at least one encoding unit by dividing an encoding unit in the form of a non-square according to an embodiment.

According to an exemplary embodiment, the video decoding apparatus 100 may use block type information indicating that the current encoding unit is a non-square format. The video decoding apparatus 100 can determine whether to divide the non-square current encoding unit according to the division type information or not in a predetermined method. 11, if the block type information of the

current encoding unit

1100 or 1150 indicates a non-square shape, the video decoding apparatus 100 determines the

current encoding unit

1100 or 1150 according to the division type information indicating that the current block is not divided 1130a, 1130b, 1130c, 1170a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1130a, 1170b, 1180a, 1180b, and 1180c. The predetermined division method in which the non-square coding unit is divided will be described in detail through various embodiments.

According to an embodiment, the video decoding apparatus 100 may determine a type in which a coding unit is divided using the division type information. In this case, the division type information indicates a number of at least one coding unit generated by dividing an encoding unit . 11, when the division type information indicates that the

current encoding unit

1100 or 1150 is divided into two encoding units, the video decoding apparatus 100 determines the

current encoding unit

1100 or 1150 based on the division type information, To determine two

encoding units

1120a, 11420b, or 1170a and 1170b included in the current encoding unit.

When the video decoding apparatus 100 divides the

current encoding unit

1100 or 1150 in the form of non-square based on the division type information according to an embodiment, the non-square

current encoding unit

1100 or 1150 The current encoding unit can be divided in consideration of the position of the long side. For example, the video decoding apparatus 100 divides the

current encoding unit

1100 or 1150 in the direction of dividing the long side of the

current encoding unit

1100 or 1150 in consideration of the type of the

current encoding unit

1100 or 1150 So that a plurality of encoding units can be determined.

According to an embodiment, when the division type information indicates division of an encoding unit into odd number of blocks, the video decoding apparatus 100 may determine an odd number of encoding units included in the

current encoding unit

1100 or 1150. For example, when the division type information indicates that the

current encoding unit

1100 or 1150 is divided into three encoding units, the video decoding apparatus 100 divides the

current encoding unit

1100 or 1150 into three encoding

units

1130a , 1130b, 1130c, 1180a, 1180b, 1180c. According to an embodiment, the video decoding apparatus 100 may determine an odd number of encoding units included in the

current encoding unit

1100 or 1150, and the sizes of the determined encoding units may not be the same. For example, the size of a

predetermined encoding unit

1130b or 1180b among the determined odd number of

encoding units

1130a, 1130b, 1130c, 1180a, 1180b, and 1180c is different from that of

other encoding units

1130a, 1130c, 1180a, and 1180c . That is, an encoding unit that can be determined by dividing the

current encoding unit

1100 or 1150 may have a plurality of types of sizes, and an odd number of

encoding units

1130a, 1130b, 1130c, 1180a, 1180b, May have different sizes.

According to an embodiment, when the division type information indicates that an encoding unit is divided into an odd number of blocks, the video decoding apparatus 100 can determine an odd number of encoding units included in the

current encoding unit

1100 or 1150, The video decoding apparatus 100 may limit a coding unit of at least one of odd number of coding units generated by division. Referring to FIG. 11, the video decoding apparatus 100 includes an

encoding unit

1130a, 1130b, 1130c, 1180a, 1180b, and 1180c generated by dividing a

current encoding unit

1100 or 1150, 1130b, and 1180b may be different from the

other encoding units

1130a, 1130c, 1180a, and 1180c. For example, in the video decoding apparatus 100, unlike the

other encoding units

1130a, 1130c, 1180a, and 1180c, the

encoding units

1130b and 1180b positioned at the center are restricted so as not to be further divided, It can be limited to be divided.

12 shows a process in which the video decoding apparatus 100 divides an encoding unit based on at least one of block type information and division type information according to an embodiment.

According to an embodiment, the video decoding apparatus 100 may determine to divide or not divide the first coding unit 1200 in units of coding units into coding units based on at least one of the block type information and the division type information. According to an embodiment, when the division type information indicates that the first encoding unit 1200 is divided in the horizontal direction, the video decoding apparatus 100 divides the first encoding unit 1200 in the horizontal direction, (1210). 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 embodiment, the video decoding apparatus 100 may determine that the determined second encoding unit 1210 is not divided or divided into encoding units based on at least one of the block type information and the division type information. 12, the video decoding apparatus 100 includes a second encoding unit 1210 of a non-square shape determined by dividing a first encoding unit 1200 based on at least one of block type information and division type information, It may be divided into at least one

third encoding unit

1220a, 1220b, 1220c, 1220d, or the like, or the second encoding unit 1210 may not be divided. The video decoding apparatus 100 can acquire at least one of block type information and division type information and the video decoding apparatus 100 can acquire at least one of the first encoding unit 1200 The second encoding unit 1210 may divide a plurality of second encoding units (for example, 1210) of various types into a first encoding unit 1210 based on at least one of block type information and division type information, The unit 1200 can be divided according to the divided method. According to one embodiment, when the first encoding unit 1200 is divided into the second encoding units 1210 based on at least one of the block type information and the division type information for the first encoding unit 1200, The encoding unit 1210 may also be divided into a third encoding unit (e.g., 1220a, 1220b, 1220c, 1220d, etc.) based on at least one of block type information and division type information for the second encoding unit 1210 have. That is, an encoding unit can be recursively divided based on at least one of division type information and block type 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. 12, among the odd

third encoding units

1220b, 1220c, and 1220d in which the non-square second encoding unit 1210 is divided and determined, predetermined encoding units (for example, An encoding unit or a square-shaped encoding unit) can be recursively divided. According to an exemplary embodiment, the third encoding unit 1220c in the form of a square, which is one of the odd numbered

third encoding units

1220b, 1220c, and 1220d, may be divided in the horizontal direction and divided into a plurality of fourth encoding units. The non-square fourth encoding unit 1240, which is one of the plurality of fourth encoding units, may be further divided into a plurality of encoding units. For example, the non-square-shaped fourth encoding unit 1240 may be further divided into odd-numbered encoding units 1250a, 1250b, and 1250c.

A method which can be used for recursive division of an encoding unit will be described later in various embodiments.

According to one embodiment, the video decoding apparatus 100 divides each of the

third encoding units

1220a, 1220b, 1220c, and 1220d into units of encoding based on at least one of block type information and division type information, It can be determined that the unit 1210 is not divided. The video decoding apparatus 100 may divide the second encoding unit 1210 in a non-square form into

third encoding units

1220b, 1220c, and 1220d in an odd number according to an embodiment. The video decoding apparatus 100 may set a predetermined restriction on a predetermined third encoding unit among odd numbered

third encoding units

1220b, 1220c, and 1220d. For example, the video decoding apparatus 100 may restrict the encoding unit 1220c located in the middle among the odd-numbered

third encoding units

1220b, 1220c, and 1220d to no longer be divided, or be divided into a set number of times . 12, the video decoding apparatus 100 may include an encoding unit (not shown) located in the middle among the odd

third encoding units

1220b, 1220c, and 1220d included in the second encoding unit 1210 in the non- 1220c may not be further divided or may be limited to being divided into a predetermined division type (for example, divided into four coding units or divided into a form corresponding to the divided form of the second coding unit 1210) (For example, dividing only n times, n > 0). The above restriction on the encoding unit 1220c positioned in the center is merely an example and should not be construed to be limited to the above embodiments and the encoding unit 1220c located in the center is not limited to the

other encoding units

1220b and 1220d Quot;), < / RTI > which can be decoded differently.

According to an embodiment, the video decoding apparatus 100 can acquire at least one of the block type information and the division type information used for dividing the current encoding unit at a predetermined position in the current encoding unit.

FIG. 13 illustrates a method for the video decoding apparatus 100 to determine a predetermined encoding unit among an odd number of encoding units according to an embodiment. 13, at least one of the block type information and the division type information of the current encoding unit 1300 is a sample of a predetermined position among a plurality of samples included in the current encoding unit 1300 (for example, Sample 1340). However, the predetermined position in the current coding unit 1300 in which at least one of the block type information and the division type information can be obtained should not be limited to the middle position shown in FIG. 13, and the current coding unit 1300 (E.g., top, bottom, left, right, top left, bottom left, top right or bottom right, etc.) The video decoding apparatus 100 may determine that the current encoding unit is not divided or divided into the encoding units of various types and sizes by acquiring at least one of the block type information and the division type information obtained from the predetermined position.

According to an exemplary embodiment, when the current encoding unit is divided into a predetermined number of encoding units, the video 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 embodiment, the video decoding apparatus 100 may divide the current encoding unit into a plurality of encoding units and determine a unit of encoding at a predetermined position.

FIG. 13 illustrates a method for the video decoding apparatus 100 to determine an encoding unit of a predetermined position among odd number of encoding units according to an embodiment.

According to an embodiment, the video decoding apparatus 100 may use information indicating positions of odd-numbered encoding units in order to determine an encoding unit located in the middle among odd-numbered encoding units. Referring to FIG. 13, the video decoding apparatus 100 may determine an odd number of

encoding units

1320a, 1320b, and 1320c by dividing the current encoding unit 1300. FIG. The video decoding apparatus 100 may determine the center encoding unit 1320b using information on the positions of odd number of

encoding units

1320a, 1320b, and 1320c. For example, the video decoding apparatus 100 determines the positions of the

encoding units

1320a, 1320b, and 1320c based on information indicating the positions of predetermined samples included in the

encoding units

1320a, 1320b, and 1320c, Can be determined. More specifically, the video decoding apparatus 100 decodes the

coding units

1320a, 1320b, and 1320c based on information indicating the positions of the upper

left samples

1330a, 1330b, and 1330c of the

coding units

1320a, 1320b, By determining the position, the coding unit 1320b located in the center can be determined.

Information indicating the positions of the upper

left samples

1330a, 1330b, and 1330c included in the

coding units

1320a, 1320b, and 1320c according to an exemplary embodiment is a position in the picture of the

coding units

1320a, 1320b, and 1320c Or information about the coordinates. Information indicating the positions of the upper

left samples

1330a, 1330b, and 1330c included in the

coding units

1320a, 1320b, and 1320c according to one embodiment is stored in the

coding units

1320a and 1320b included in the current coding unit 1300 And 1320c, and the width or height may correspond to information indicating a difference between coordinates in the picture of the

encoding units

1320a, 1320b, and 1320c. That is, the video decoding apparatus 100 can directly use the information on the position or the coordinates in the picture of the

coding units

1320a, 1320b, and 1320c or the information on the width or height of the coding unit corresponding to the difference value between the coordinates The encoding unit 1320b located in the center can be determined.

The information indicating the position of the upper left sample 1330a of the upper coding unit 1320a may indicate the coordinates (xa, ya) and the upper left sample 1330b of the middle coding unit 1320b May represent the coordinates (xb, yb), and the information indicating the position of the upper left sample 1330c of the lower coding unit 1320c may indicate the coordinates (xc, yc). The video decoding apparatus 100 can determine the center encoding unit 1320b using the coordinates of the upper

left samples

1330a, 1330b, and 1330c included in the

encoding units

1320a, 1320b, and 1320c. For example, when the coordinates of the upper

left samples

1330a, 1330b, and 1330c are sorted in ascending or descending order, the coding unit 1320b including the coordinates (xb, yb) of the sample 1330b positioned at the center, May be determined as a coding unit located in the middle of the

coding units

1320a, 1320b, and 1320c determined by dividing the current coding unit 1300. [ However, the coordinates indicating the positions of the

samples

1330a, 1330b, and 1330c in the upper left corner may indicate the coordinates indicating the absolute position in the picture, and the position of the upper left sample 1330a of the upper coding unit 1320a may be (Dxb, dyb), which is the information indicating the relative position of the sample 1330b at the upper left of the middle encoding unit 1320b, and the relative position of the sample 1330c at the upper left of the lower encoding unit 1320c 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.

The video decoding apparatus 100 may divide the current encoding unit 1300 into a plurality of

encoding units

1320a, 1320b, and 1320c and may convert the

encoding units

1320a, 1320b, The encoding unit can be selected. For example, the video decoding apparatus 100 can select an encoding unit 1320b having a different size from among the encoding

units

1320a, 1320b, and 1320c.

According to an embodiment, the video decoding apparatus 100 may be configured to include (xa, ya) coordinates, which is information indicating the position of the upper left sample 1330a of the upper encoding unit 1320a, (Xc, yc) coordinates, which is information indicating the position of the lower-stage coding unit 1330b and the position of the upper-left sample 1330c of the lower-

stage coding unit

1320c, 1320b, and 1320c, respectively. The video decoding apparatus 100 encodes the

encoding units

1320a, 1320b, and 1320c using the coordinates (xa, ya), (xb, yb), (xc, yc) indicating the positions of the encoding units 1320a, ) Can be determined.

According to one embodiment, the video decoding apparatus 100 can determine the width of the upper encoding unit 1320a as xb-xa and the height as yb-ya. According to an embodiment, the video decoding apparatus 100 can determine the width of the middle encoding unit 1320b as xc-xb and the height as yc-yb. The video 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 1320a and the middle encoding unit 1320b . The video 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

1320a, 1320b, and 1320c. Referring to FIG. 13, the video decoding apparatus 100 may determine a coding unit 1320b as a coding unit at a predetermined position while having a size different from that of the upper coding unit 1320a and the lower coding unit 1320c. However, the process of the above-described video decoding apparatus 100 determining an encoding unit having a size different from that of the other encoding units may be the same as the process of determining an encoding unit at a predetermined position using the size of an encoding unit determined based on 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 an embodiment, the video decoding apparatus 100 may select a coding unit at a predetermined position among the odd number of coding units in which the current coding unit is divided by 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 video decoding apparatus 100 can determine a coding unit at a predetermined position along the horizontal direction. That is, the video decoding apparatus 100 may determine one of the encoding units that are located in the horizontal direction and set a restriction on the encoding unit. If the current coding unit is a non-square shape having a height greater than the width, the video decoding apparatus 100 can determine a coding unit at a predetermined position in the vertical direction. That is, the video decoding apparatus 100 may determine one of the encoding units which are located in the vertical direction and limit the encoding unit.

According to an exemplary embodiment, the video decoding apparatus 100 may use information indicating positions of even-numbered encoding units to determine encoding units at predetermined positions among the even-numbered encoding units. The video decoding apparatus 100 can determine an even number of encoding units by dividing the current encoding unit and determine a encoding unit at a predetermined position 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, a 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 among the coding units in which the current coding unit is divided into a plurality of coding units, the video decoding apparatus 100 may include block type information stored in a sample included in the middle coding unit, Information can be used.

13, the video decoding apparatus 100 may divide the current encoding unit 1300 into a plurality of

encoding units

1320a, 1320b, and 1320c based on at least one of the block type information and the division type information, The encoding unit 1320b positioned in the middle of the plurality of

encoding units

1320a, 1320b, and 1320c can be determined. Furthermore, the video decoding apparatus 100 may determine a coding unit 1320b positioned at the center in consideration of a position where at least one of the block type information and the division type information is obtained. That is, at least one of the block type information and the division type information of the current encoding unit 1300 can be acquired in the sample 1340 located in the middle of the current encoding unit 1300, and the block type information and the division type information If the current encoding unit 1300 is divided into a plurality of

encoding units

1320a, 1320b, and 1320c based on at least one of the encoding units 1320a to 1320c and 1320c, You can decide. However, the information used for determining the coding unit located in the middle should not be limited to at least one of the block type information and the division type information, and various kinds of information may 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. 13, the video decoding apparatus 100 includes a plurality of

coding units

1320a, 1320b, and 1320c, which are determined by dividing the current coding unit 1300, and encoding units (for example, (For example, a sample located in the middle of the current encoding unit 1300) at a predetermined position in the current encoding unit 1300 in order to determine an encoding unit located in the middle of the encoding unit, And at least one of division type information. . That is, the video decoding apparatus 100 can determine the sample of the predetermined position in consideration of the block block type of the current encoding unit 1300, and the video decoding apparatus 100 determines that the current encoding unit 1300 is divided A coding unit 1320b including a sample from which predetermined information (for example, at least one of block type information and division type information) can be obtained is determined among a plurality of

coding units

1320a, 1320b, and 1320c A predetermined limit can be set. Referring to FIG. 13, the video decoding apparatus 100 may determine a sample 1340 located in the middle of a current encoding unit 1300 as a sample from which predetermined information can be obtained, The coding unit 100 may limit the coding unit 1320b including the sample 1340 to a predetermined limit in the decoding process. However, the position of the sample from which predetermined information can be obtained can not be construed to be limited to the above-mentioned position, but can be interpreted as samples at arbitrary positions included in the encoding unit 1320b to be determined for limiting.

The position of a sample from which predetermined information can be obtained according to an embodiment may be determined according to the type of the current encoding unit 1300. 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 encoding unit and the information on the height, and may be located on a boundary that divides at least one of the width and the height of the current encoding unit by half The sample can be determined as a sample from which predetermined information can be obtained. In another example, when the video decoding apparatus 100 indicates that the block type information related to the current encoding unit is a non-square format, one of the samples adjacent to the boundary dividing the long side of the current encoding unit into half is divided into 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 video decoding apparatus 100 may determine at least one of the block type information and the division type information One can be used. According to an embodiment, the video decoding apparatus 100 can acquire at least one of the block type information and the division type information from a sample at a predetermined position included in an encoding unit, and the video decoding apparatus 100 determines whether the current encoding unit is divided And divide the generated plurality of coding units by using at least one of division type information and block type information obtained from samples at predetermined positions included in each of the plurality of coding units. That is, the coding unit can be recursively divided using at least one of the block type information and the division type information obtained in the sample at the predetermined position included in each of the coding units. Since the recursive division process of the encoding unit has been described with reference to FIG. 12, a detailed description will be omitted.

According to an embodiment, the video decoding apparatus 100 may 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, ). &Lt; / RTI >

FIG. 14 shows a sequence in which a plurality of coding units are processed when the video decoding apparatus 100 determines a plurality of coding units by dividing a current coding unit according to an embodiment.

According to an embodiment, the video decoding apparatus 100 divides the first encoding unit 1400 in the vertical direction according to the block type information and the division type information to determine the

second encoding units

1410a and 1410b, 1450b, 1450c, and 1450d by dividing the first coding unit 1400 in the horizontal direction to determine the

second coding units

1430a and 1430b or dividing the first coding unit 1400 in the vertical direction and the horizontal direction, Can be determined.

Referring to FIG. 14, the video decoding apparatus 100 may determine the order in which the

second encoding units

1410a and 1410b determined by dividing the first encoding unit 1400 in the vertical direction are processed in the horizontal direction 1410c . The video decoding apparatus 100 may determine the processing order of the

second encoding units

1430a and 1430b determined by dividing the first encoding unit 1400 in the horizontal direction as the vertical direction 1430c. The video decoding apparatus 100 processes the encoding units located in one row of the

second encoding units

1450a, 1450b, 1450c, and 1450d determined by dividing the first encoding unit 1400 in the vertical direction and the horizontal direction (For example, a raster scan order or a z scan order 1450e) in which the encoding units located in the next row are processed.

According to an embodiment, the video decoding apparatus 100 may recursively divide encoding units. 14, the video decoding apparatus 100 may determine a plurality of

encoding units

1410a, 1410b, 1430a, 1430b, 1450a, 1450b, 1450c, and 1450d by dividing the first encoding unit 1400, It is possible to recursively divide each of the determined plurality of

encoding units

1410a, 1410b, 1430a, 1430b, 1450a, 1450b, 1450c, and 1450d. The method of dividing the plurality of

encoding units

1410a, 1410b, 1430a, 1430b, 1450a, 1450b, 1450c, and 1450d may be a method corresponding to the method of dividing the first encoding unit 1400. [ Accordingly, the plurality of

coding units

1410a, 1410b, 1430a, 1430b, 1450a, 1450b, 1450c, and 1450d may be independently divided into a plurality of coding units. Referring to FIG. 14, the video decoding apparatus 100 may determine the

second encoding units

1410a and 1410b by dividing the first encoding unit 1400 in the vertical direction, and may further determine the

second encoding units

1410a and 1410b Can be determined not to divide or separate independently.

The video decoding apparatus 100 may divide the left second encoding unit 1410a in the horizontal direction into the

third encoding units

1420a and 1420b and the second encoding units 1410b ) 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 video decoding apparatus 100 can determine the order in which the

third coding units

1420a and 1420b determined by dividing the left second coding unit 1410a are processed independently of the second coding unit 1410b on the right side. The

third coding units

1420a and 1420b may be processed in the vertical direction 1420c since the second coding units 1410a on the left side are divided in the horizontal direction and the

third coding units

1420a and 1420b are determined. Since the order in which the left second encoding unit 1410a and the right second encoding unit 1410b are processed corresponds to the horizontal direction 1410c, the third encoding unit 1410a included in the left second encoding unit 1410a, The right encoding unit 1410b can be processed after the

blocks

1420a and 1420b are processed in the vertical direction 1420c. 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.

FIG. 15 illustrates a process of determining that the current encoding unit is divided into odd number of encoding units when the video decoding apparatus 100 can not process the encoding units in a predetermined order according to an embodiment.

According to an embodiment, the video decoding apparatus 100 may determine that the current encoding unit is divided into odd number of encoding units based on the obtained block type information and the division type information. Referring to FIG. 15, the first encoding unit 1500 in a square form may be divided into second

non-square encoding units

1510a and 1510b, and the

second encoding units

1510a and 1510b may be independently 3

encoding units

1520a, 1520b, 1520c, 1520d, and 1520e. According to an embodiment, the video decoding apparatus 100 may determine a plurality of

third encoding units

1520a and 1520b by dividing the left encoding unit 1510a of the second encoding unit in the horizontal direction, May be divided into an odd number of

third encoding units

1520c, 1520d, and 1520e.

According to one embodiment, the video decoding apparatus 100 determines whether or not the

third encoding units

1520a, 1520b, 1520c, 1520d, and 1520e can be processed in a predetermined order and determines whether there are odd-numbered encoding units You can decide. Referring to FIG. 15, the video decoding apparatus 100 may recursively divide the first encoding unit 1500 to determine the

third encoding units

1520a, 1520b, 1520c, 1520d, and 1520e. The video decoding apparatus 100 may further include a first coding unit 1500, a

second coding unit

1510a and 1510b or a

third coding unit

1520a, 1520b, 1520c, and 1520c based on at least one of block type information and division type information, 1520d, and 1520e may be 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

1510a and 1510b may be divided into odd

third encoding units

1520c, 1520d, and 1520e. The order in which the plurality of coding units included in the first coding unit 1500 are processed may be a predetermined order (for example, a z-scan order 1530) 100 can determine whether the

third encoding units

1520c, 1520d, and 1520e determined by dividing the right second encoding unit 1510b into odd numbers satisfy the condition that the

third encoding units

1520c, 1520d, and 1520e can be processed according to the predetermined order.

According to an embodiment, the video decoding apparatus 100 satisfies a condition that

third encoding units

1520a, 1520b, 1520c, 1520d, and 1520e included in the first encoding unit 1500 can be processed in a predetermined order And it is determined whether or not at least one of the width and the height of the

second encoding units

1510a and 1510b is divided in half according to the boundaries of the

third encoding units

1520a, 1520b, 1520c, 1520d, and 1520e . For example, the

third coding units

1520a and 1520b determined by dividing the height of the left-side second coding unit 1510a in the non-square form by half are satisfied, but the right second coding unit 1510b is set to 3 Since the boundaries of the

third encoding units

1520c, 1520d, and 1520e determined by dividing the number of

encoding units

1520c, 1520d, and 1520e can not divide the width or height of the right second encoding unit 1510b in half, The video decoding apparatus 100 may determine that the condition is not satisfied and the video decoding apparatus 100 determines that the scanning order is disconnection in the case of such unsatisfactory condition and the right second encoding unit 1510b is based on the determination result It can be determined to be divided into odd number of encoding units. According to an exemplary embodiment, when the video decoding apparatus 100 is divided into odd-numbered coding units, the video decoding apparatus 100 may limit a coding unit of a predetermined position among the divided coding units. Since the embodiment has been described above, a detailed description thereof will be omitted.

16 illustrates a process in which the video decoding apparatus 100 determines at least one encoding unit by dividing a first encoding unit 1600 according to an embodiment. The video decoding apparatus 100 may divide the first encoding unit 1600 based on at least one of the block type information and the division type information acquired through the acquisition unit 110. [ The first encoding unit 1600 in the form of a square may be divided into four encoding units having a square shape or may be divided into a plurality of non-square encoding units. For example, referring to FIG. 16, when the block type information indicates that the first encoding unit 1600 is square and the division type information is divided into non-square encoding units, the video decoding apparatus 100 transmits the first encoding unit The encoding unit 1600 may be divided into a plurality of non-square encoding units. More specifically, when the division type information indicates that the first encoding unit 1600 is divided horizontally or vertically to determine an odd number of encoding units, the video decoding apparatus 100 includes a first encoding unit 1600 in the form of a square 1620b, and 1610c divided in the vertical direction as the odd number of coding units, or into the second coding units 1620a, 1620b, and 1620c determined by being divided in the horizontal direction.

According to an embodiment, the video decoding apparatus 100 may be configured such that the

second encoding units

1610a, 1610b, 1610c, 1620a, 1620b, and 1620c included in the first encoding unit 1600 can be processed in a predetermined order And the condition is that at least one of the width and height of the first encoding unit 1600 is divided in half according to the boundaries of the

second encoding units

1610a, 1610b, 1610c, 1620a, 1620b, and 1620c . 16, the boundaries of the

second encoding units

1610a, 1610b, and 1610c, which are determined by dividing the first encoding unit 1600 in the vertical direction, are divided in half by the width of the first encoding unit 1600 The first encoding unit 1600 can be determined as not satisfying a condition that can be processed in a predetermined order. In addition, since the boundaries of the second encoding units 1620a, 1620b, and 1620c determined by dividing the first encoding unit 1600 in the horizontal direction into the horizontal direction can not divide the width of the first encoding unit 1600 in half, 1 encoding unit 1600 may be determined as not satisfying a condition that can be processed in a predetermined order. The video decoding apparatus 100 may determine that the scan sequence is disconnection in the case of such unsatisfactory condition and determine that the first encoding unit 1600 is divided into odd number of encoding units based on the determination result. According to an exemplary embodiment, when the video decoding apparatus 100 is divided into odd-numbered coding units, the video decoding apparatus 100 may limit a coding unit of a predetermined position among the divided coding units. Since the embodiment has been described above, a detailed description thereof will be omitted.

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

16, the video decoding apparatus 100 may divide a first coding unit 1600 in a square form and a

first coding unit

1630 or 1650 in a non-square form into various types of coding units .

17 is a diagram illustrating a case where the second encoding unit is divided when the non-square second encoding unit determined by dividing the first encoding unit 1700 by the video decoding apparatus 100 satisfies a predetermined condition Lt; RTI ID = 0.0 > limited. &Lt; / RTI >

According to an embodiment, the video decoding apparatus 100 may convert a first encoded unit 1700 of a square form into a non-square format (e.g., a first encoded unit 1700) based on at least one of the block type information and the division type information acquired through the acquisition unit 105 It can be determined to divide it into the

second encoding units

1710a, 1710b, 1720a, and 1720b. The

second encoding units

1710a, 1710b, 1720a, and 1720b may be independently divided. Accordingly, the video decoding apparatus 100 determines whether to divide or not divide into a plurality of coding units based on at least one of the block type information and the division type information related to each of the

second coding units

1710a, 1710b, 1720a, and 1720b . According to an embodiment, the video decoding apparatus 100 divides the left second encoding unit 1710a in the non-square form determined by dividing the first encoding unit 1700 in the vertical direction into the horizontal direction, 1712a, and 1712b. However, in the case where the left second encoding unit 1710a is divided in the horizontal direction, the right side second encoding unit 1710b is arranged in the horizontal direction in the same way as the direction in which the left second encoding unit 1710a is divided, As shown in Fig. When the right second encoding unit 1710b is divided in the same direction and the

third encoding units

1714a and 1714b are determined, the left second encoding unit 1710a and the right second encoding unit 1710b are arranged in the horizontal direction The

third encoding units

1712a, 1712b, 1714a, and 1714b can be determined by being independently divided. However, the video decoding apparatus 100 divides the first encoding unit 1700 into four square-shaped

second encoding units

1730a, 1730b, 1730c, and 1730d based on at least one of the block type information and the division type information. And this may be inefficient in terms of image decoding.

According to an embodiment, the video decoding apparatus 100 divides the

second encoding unit

1720a or 1720b in the non-square form determined by dividing the first encoding unit 11300 in the horizontal direction into the vertical direction, (1722a, 1722b, 1724a, 1724b). However, when one of the second coding units (for example, the upper second coding unit 1720a) is divided in the vertical direction, the video decoding apparatus 100 may generate a second coding unit (for example, Coding unit 1720b) can be restricted such that the upper second encoding unit 1720a can not be divided vertically in the same direction as the divided direction.

FIG. 18 illustrates a process in which the video decoding apparatus 100 divides a square-shaped encoding unit when the division type information can not be divided into four square-shaped encoding units according to an embodiment.

According to an embodiment, the video decoding apparatus 100 divides the first encoding unit 1800 based on at least one of the block type information and the division type information, and outputs the

second encoding units

1810a, 1810b, 1820a, and 1820b You can decide. The division type information may include information on various types in which the coding unit can be divided, but information on various types may not include information for dividing into four square units of coding units. According to the division type information, the video decoding apparatus 100 can not divide the first encoding unit 1800 in the square form into the

second encoding units

1830a, 1830b, 1830c, and 1830d in the form of four squares. Based on the division type information, the video decoding apparatus 100 can determine the

second encoding units

1810a, 1810b, 1820a, and 1820b in the non-square form.

According to an embodiment, the video decoding apparatus 100 may independently divide the

second encoding units

1810a, 1810b, 1820a, and 1820b in the non-square form. Each of the

second encoding units

1810a, 1810b, 1820a, 1820b, and the like may be divided in a predetermined order through a recursive method, and the first encoding unit 1800 May be a partitioning method corresponding to a method in which a partition is divided.

For example, the video decoding apparatus 100 can determine the

third encoding units

1812a and 1812b in the form of a square by dividing the left second encoding unit 1810a in the horizontal direction, and the right second encoding unit 1810b It is possible to determine the

third encoding units

1814a and 1814b in the form of a square by being divided in the horizontal direction. Further, the video decoding apparatus 100 may divide the left second encoding unit 1810a and the right second encoding unit 1810b in the horizontal direction to determine the square-shaped

third encoding units

1816a, 1816b, 1816c, and 1816d have. In this case, the encoding unit may be determined in the same manner as the first encoding unit 1800 is divided into the four second-type

second encoding units

1830a, 1830b, 1830c, and 1830d.

In another example, the video decoding apparatus 100 can determine the

third encoding units

1822a and 1822b in the form of a square by dividing the upper second encoding unit 1820a in the vertical direction, and the lower second encoding units 1820b May be divided in the vertical direction to determine the

third encoding units

1824a and 1824b in the form of a square. Further, the video decoding apparatus 100 may divide the upper second encoding unit 1820a and the lower second encoding unit 1820b in the vertical direction to determine the square-shaped

third encoding units

1822a, 1822b, 1824a, and 1824b have. In this case, the encoding unit may be determined in the same manner as the first encoding unit 1800 is divided into the four second-type

second encoding units

1830a, 1830b, 1830c, and 1830d.

According to an embodiment, the video decoding apparatus 100 may divide the first encoding unit 1900 based on the block type information and the division type information. When the block type information indicates a square shape and the division type information indicates that the first encoding unit 1900 is divided into at least one of a horizontal direction and a vertical direction, the video decoding apparatus 100 includes a first encoding unit 1900 (For example, 1910a, 1910b, 1920a, 1920b, 1930a, 1930b, 1930c, 1930d, etc.) can be determined. Referring to FIG. 19, the non-square

second encoding units

1910a, 1910b, 1920a, and 1920b, which are determined by dividing the first encoding unit 1900 only in the horizontal direction or the vertical direction, As shown in FIG. For example, the video decoding apparatus 100 divides the

second encoding units

1910a and 1910b, which are generated by dividing the first encoding unit 1900 in the vertical direction, in the horizontal direction to generate

third encoding units

1916a, 1916b, 1926c and 1916d can be determined and the

second encoding units

1920a and 1920b generated by dividing the first encoding unit 1900 in the horizontal direction are divided in the horizontal direction and the

third encoding units

1926a, 1926b, and 1926c , 1926d) can be determined. Since the process of dividing the

second encoding units

1910a, 1910b, 1920a, and 1920b has been described in detail with reference to FIG. 17, a detailed description thereof will be omitted.

According to an embodiment, the video decoding apparatus 100 may process an encoding unit in a predetermined order. The features of the processing of the encoding unit in the predetermined order have been described in detail with reference to FIG. 14, and a detailed description thereof will be omitted. 19, the video decoding apparatus 100 divides a first encoding unit 1900 in a square form into four quadrangle-shaped

third encoding units

1916a, 1916b, 1916c, 1916d, 1926a, 1926b, 1926c, and 1926d Can be determined. According to an embodiment, the video decoding apparatus 100 may process the

third encoding units

1916a, 1916b, 1916c, 1916d, 1926a, 1926b, 1926c, and 1926d according to the form in which the first encoding unit 1900 is divided You can decide.

According to an embodiment, the video decoding apparatus 100 divides the

second encoding units

1910a and 1910b generated in the vertical direction and divides them in the horizontal direction to determine the

third encoding units

1916a, 1916b, 1916c, and 1916d And the video decoding apparatus 100 first processes the

third encoding units

1916a and 1916b included in the left second encoding unit 1910a in the vertical direction and then processes the

third encoding units

1916a and 1916b included in the right second encoding unit 1910b The

third encoding units

1916a, 1916b, 1916c, and 1916d can be processed in accordance with the order 1917 of processing the

third encoding units

1916c and 1916d in the vertical direction.

According to an embodiment, the video decoding apparatus 100 divides the

second encoding units

1920a and 1920b generated in the horizontal direction into vertical directions to determine the

third encoding units

1926a, 1926b, 1926c, and 1926d And the video decoding apparatus 100 first processes the

third encoding units

1926a and 1926b included in the upper second encoding unit 1920a in the horizontal direction and then processes the

third encoding units

1926a and 1926b included in the lower second encoding unit 1920b The

third encoding units

1926a, 1926b, 1926c, and 1926d can be processed according to the order 1927 of processing the

third encoding units

1926c and 1926d in the horizontal direction.

Referring to FIG. 19, the

second encoding units

1910a, 1910b, 1920a, and 1920b are divided to determine the

third encoding units

1916a, 1916b, 1916c, 1916d, 1926a, 1926b, 1926c, and 1926d, have. The

second encoding units

1910a and 1910b determined to be divided in the vertical direction and the

second encoding units

1920a and 1920b determined to be divided in the horizontal direction are divided into different formats, but the

third encoding unit

1916a , 1916b, 1916c, 1916d, 1926a, 1926b, 1926c, and 1926d, the result is that the first encoding unit 1900 is divided into the same type of encoding units. Accordingly, the video decoding apparatus 100 recursively divides the encoding units through different processes based on at least one of the block type information and the division type information, thereby eventually determining the same type of encoding units, Lt; RTI ID = 0.0 > units of < / RTI >

According to an embodiment, the video 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 coding unit is divided by 2n (n > 0) times longer than the length of the long side of the coding unit before the current coding unit is divided, the depth of the current coding unit is smaller than the depth of the coding 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. 20, on the basis of block type information (for example, block type information may indicate '0: SQUARE') indicating a square form according to an embodiment, the video decoding apparatus 100 generates a square 1 coding unit 2000 can be divided to determine the second coding unit 2002, the third coding unit 2004, etc. of the lower depth. If the size of the first encoding unit 2000 in the form of a square is 2Nx2N, the second encoding unit 2002 determined by dividing the width and height of the first encoding unit 2000 by 1/21 times may have a size of NxN have. Furthermore, the third encoding unit 2004 determined by dividing the width and height of the second encoding unit 2002 by a half size may have a size of N / 2xN / 2. In this case, the width and the height of the third encoding unit 2004 correspond to 1/22 of the first encoding unit 2000. When the depth of the first encoding unit 2000 is D, the depth of the second encoding unit 2002, which is 1/21 times the width and height of the first encoding unit 2000, may be D + 1, The depth of the third encoding unit 2004, which is one-22 times the width and height of the second encoding unit 2000, 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 >: NS_HOR '), the video decoding apparatus 100 divides the

first coding unit

2010 or 2020 in a non-square form to generate a

second coding unit

2012 or 2022 of lower depth, The third encoding unit 2014 or 2024, or the like.

The video decoding apparatus 100 may determine a second encoding unit (e.g., 2002, 2012, 2022, etc.) by dividing at least one of the width and the height of the first encoding unit 2010 of Nx2N size. That is, the video decoding apparatus 100 can determine the second encoding unit 2002 of the NxN size or the second encoding unit 2022 of the NxN / 2 size by dividing the first encoding unit 2010 in the horizontal direction, The second encoding unit 2012 may be divided into the horizontal direction and the vertical direction to determine the second encoding unit 2012 of N / 2xN size.

According to an embodiment, the video decoding apparatus 100 divides at least one of the width and the height of the 2NxN-size first encoding unit 2020 to determine a second encoding unit (for example, 2002, 2012, 2022, etc.) It is possible. That is, the video decoding apparatus 100 can determine the second encoding unit 2002 of NxN size or the second encoding unit 2012 of N / 2xN size by dividing the first encoding unit 2020 in the vertical direction, The second encoding unit 2022 of the NxN / 2 size may be determined by dividing the image data in the horizontal direction and the vertical direction.

According to an embodiment, the video decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 2002 of NxN size to determine a third encoding unit (for example, 2004, 2014, 2024, etc.) It is possible. That is, the video decoding apparatus 100 determines the third encoding unit 2004 of N / 2xN / 2 size by dividing the second encoding unit 2002 in the vertical direction and the horizontal direction, 3 encoding unit 2014 or a third encoding unit 2024 of N / 2xN / 22 size.

According to an embodiment, the video decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 2012 of N / 2xN size, and encodes the third encoding unit (for example, 2004, 2014, 2024, . That is, the video decoding apparatus 100 divides the second encoding unit 2012 in the horizontal direction to generate a third encoding unit 2004 of N / 2xN / 2 or a third encoding unit 2024 of N / 2xN / 22 size ) Or may be divided into vertical and horizontal directions to determine a third encoding unit 2014 of N / 22xN / 2 size.

According to an embodiment, the video decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 2014 of NxN / 2 size into a third encoding unit (e.g., 2004, 2014, 2024, etc.) . That is, the video decoding apparatus 100 divides the second encoding unit 2012 in the vertical direction to obtain a third encoding unit 2004 of N / 2xN / 2 or a third encoding unit 2014 of N / 22xN / 2 size ) Or may be divided into vertical and horizontal directions to determine a third encoding unit 2024 of N / 2xN / 22 size.

According to an embodiment, the video decoding apparatus 100 may divide a square-shaped encoding unit (for example, 2000, 2002, 2004) into a horizontal direction or a vertical direction. For example, the first encoding unit 2000 of the size 2Nx2N is divided in the vertical direction to determine the first encoding unit 2010 of the size Nx2N or the horizontal direction to determine the first encoding unit 2020 of 2NxN size . If the depth is determined based on the length of the longest side of the encoding unit according to one embodiment, the depth of the encoding unit in which the

first encoding unit

2000, 2002, or 2004 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 (2000, 2002 or 2004).

According to one embodiment, the width and height of the third encoding unit 2014 or 2024 may correspond to 1/22 of the first encoding unit (2010 or 2020). When the depth of the

first coding unit

2010 or 2020 is D, the depth of the second coding unit 2012 or 2014, which is half the width and height of the

first coding unit

2010 or 2020, is D + 1 And the depth of the third coding unit 2014 or 2024 which is 1/22 times the width and height of the

first coding unit

2010 or 2020 may be D + 2.

According to an embodiment, the video decoding apparatus 100 may divide the first encoding unit 2100 in a square form to determine various types of second encoding units. 21, the video decoding apparatus 100 divides the first coding unit 2100 into at least one of a vertical direction and a horizontal direction according to the division type information, and outputs the

second coding units

2102a, 2102b, 2104a, 2104b, 2106a, 2106b, 2106c, and 2106d. That is, the video decoding apparatus 100 can determine the

second encoding units

2102a, 2102b, 2104a, 2104b, 2106a, 2106b, 2106c, and 2106d based on the division type information for the first encoding unit 2100. [

The

second encoding units

2102a, 2102b, 2104a, 2104b, 2106a, 2106b, 2106c, and 2106d, which are determined according to the division type information for the first encoding unit 2100 in a square form, Depth can be determined based on. For example, since the length of one side of the first encoding unit 2100 in the square form is the same as the length of long sides of the

second encoding units

2102a, 2102b, 2104a, and 2104b in the non-square form, 2100 and the non-square type

second encoding units

2102a, 2102b, 2104a, and 2104b are denoted by D in the same manner. On the other hand, when the video decoding apparatus 100 divides the first encoding unit 2100 into four square-shaped

second encoding units

2106a, 2106b, 2106c, and 2106d based on the division type information, The length of one side of the

second encoding units

2106a, 2106b, 2106c and 2106d is one-half the length of one side of the first encoding unit 2100. Therefore, the depths of the

second encoding units

2106a, 2106b, May be a depth of D + 1 that is one depth lower than D, which is the depth of the first encoding unit 2100.

According to an embodiment, the video decoding apparatus 100 divides a first coding unit 2110 having a height greater than a width in a horizontal direction according to the division type information, and generates a plurality of

second coding units

2112a, 2112b, 2114a, 2114b, and 2114c. According to an embodiment, the video decoding apparatus 100 divides the first coding unit 2120 of a shape whose width is longer than a height in the vertical direction according to the division type information, and generates a plurality of

second coding units

2122a, 2122b, 2124a, 2124b, and 2124c.

The

second encoding units

2112a, 2112b, 2114a, 2114b, 2116a, 2116b, 2116c, and 2116d determined according to the division type information for the

first encoding unit

2110 or 2120 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

2112a and 2112b is 1/2 times the length of one side of the non-square first encoding unit 2110 whose height is longer than the width, The depth of the

second encoding units

2102a, 2102b, 2104a and 2104b in the form of D + 1 is one depth lower than the depth D of the first encoding unit 2110 in the non-square form.

Furthermore, the video decoding apparatus 100 may divide the non-square first encoding unit 2110 into odd

second encoding units

2114a, 2114b, and 2114c based on the division type information. The odd number of

second encoding units

2114a, 2114b and 2114c may include non-square

second encoding units

2114a and 2114c and a square second encoding unit 2114b. In this case, the length of the longer sides of the non-square

second encoding units

2114a and 2114c and the length of one side of the second encoding unit 2114b of the square shape are 1 / The depth of the

second encoding units

2114a, 2114b and 2114c may be a depth of D + 1 which is one depth lower than the depth D of the first encoding unit 2110. [ The video decoding apparatus 100 is connected to the first encoding unit 2120 in the form of a non-square shape whose width is longer than the height in a manner corresponding to the scheme for determining the depths of the encoding units associated with the first encoding unit 2110 The depth of the encoding units can be determined.

According to an exemplary embodiment, the video decoding apparatus 100 determines an index (PID) for distinguishing divided coding units. If the odd-numbered coding units are not the same size, The index can be determined based on the index. 21, an encoding unit 2114b positioned at the center among the odd-numbered

encoding units

2114a, 2114b, and 2114c has the same width as

other encoding units

2114a and 2114c, May be two times as high as the height of the first and

second electrodes

2114a and 2114c. That is, in this case, the coding unit 2114b positioned at the center may include two of the

other coding units

2114a and 2114c. Accordingly, if the index (PID) of the coding unit 2114b positioned at the center is 1 according to the scanning order, the coding unit 2114c positioned next to the coding unit 2114c 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 embodiment, the video 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 embodiment, the video decoding apparatus 100 may determine whether the video decoding apparatus 100 is divided into a specific division type based on a value of an index for identifying a plurality of coding units divided and determined from the current coding unit. 21, the video decoding apparatus 100 divides a rectangular first encoding unit 2110 having a height greater than the width to determine even-numbered

encoding units

2112a and 2112b or odd-numbered

encoding units

2114a and 2114b , 2114c can be determined. The video decoding apparatus 100 may use an index (PID) indicating each coding unit in order to identify 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 video decoding apparatus 100 may determine a coding unit at a predetermined position among the coding units divided and determined using an index for classifying a coding unit. According to an embodiment, when the division type information for the rectangular first type encoding unit 2110 whose height is longer than the width is divided into three encoding units, the video decoding apparatus 100 transmits the first encoding unit 2110 It can be divided into three encoding

units

2114a, 2114b, and 2114c. The video decoding apparatus 100 can assign an index to each of the three

encoding units

2114a, 2114b, and 2114c. The video 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 video decoding apparatus 100 encodes an encoding unit 2114b having an index corresponding to a middle value among indices based on indexes of encoding units into an encoding unit 2114b encoding an intermediate position among encoding units determined by dividing the first encoding unit 2110 Can be determined as a unit. According to an embodiment, the video 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 . 21, the coding unit 2114b generated by dividing the first coding unit 2110 is divided into

coding units

2114a and 2114c having the same width as the

coding units

2114a and 2114c but different in height Can be double the height. In this case, if the index (PID) of the coding unit 2114b positioned at the center is 1, the coding unit 2114c located next to the coding unit 2114c may be three (3) In this case, if the index increases uniformly and the increment increases, the video decoding apparatus 100 may determine that the encoding unit is divided into a plurality of encoding units including encoding units having different sizes from other encoding units. , The video 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 has a format different from that of the other encoding units The current encoding unit can be divided into. In this case, the video 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 embodiment, the video decoding apparatus 100 may use a predetermined data unit in which recursive division of an encoding unit starts.

According to an exemplary embodiment, a predetermined data unit may be defined as a data unit in which an encoding unit starts to be recursively segmented using at least one of block type information and partition type information. That is, it may correspond to a coding unit of the highest depth used in the process of determining a plurality of coding units for dividing the 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 video decoding apparatus 100 may divide the current picture into a plurality of reference data units. According to an embodiment, the video decoding apparatus 100 may divide a plurality of reference data units for dividing a current picture into pieces using 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 video decoding apparatus 100 may determine in advance the minimum size that the reference data unit included in the current picture can have. Accordingly, the video decoding apparatus 100 can determine reference data units of various sizes having sizes equal to or larger than a minimum size, and determine at least one coding unit using block type information and division type information based on the determined reference data unit You can decide.

22, the video decoding apparatus 100 may use a reference encoding unit 2200 in a square form or a reference encoding unit 2202 in a non-square form. 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 obtaining unit 105 of the video decoding apparatus 100 may obtain at least one of the information on the type of the reference encoding unit and the size of the reference encoding unit from the bit stream for each of the various data units have. The process of determining at least one encoding unit included in the reference-type encoding unit 2200 in the form of a square is described in detail in the process of dividing the current encoding unit 300 of FIG. 10, and the non- 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 type of the reference encoding unit according to a predetermined data unit predetermined based on a predetermined condition, the video decoding apparatus 100 may include an index for identifying the size and type of the reference encoding unit Can be used. That is, the acquiring unit 105 acquires from the bitstream a predetermined condition (for example, a data unit having a size equal to or smaller than a slice) among the various data units (e.g., sequence, picture, slice, slice segment, ), It is possible to obtain only an index for identification of the size and type of the reference encoding unit for each slice, slice segment, maximum encoding unit, and the like. The video decoding apparatus 100 can determine the size and type 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 video decoding apparatus 100 selects at least one of the size and the type of the reference encoding unit included in the data unit that is the basis of the index acquisition by selecting at least one of the size and the shape of the predetermined reference encoding unit You can decide.

According to an exemplary embodiment, the video 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 video 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 block type information and the division type information As shown in FIG.

23 shows a processing block serving as a reference for determining a determination order of the reference encoding units included in the picture 2300 according to an embodiment.

According to one embodiment, the video 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 video decoding apparatus 100 may obtain information on the size of the processing block to determine the size of the at least one processing block included in the image. The video 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 obtaining unit 105 of the video 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, and the like. That is, the obtaining unit 105 may obtain information on the size of the processing block from the bitstream for each of the plurality of data units, and the video decoding apparatus 100 divides the picture using information on the size of the obtained processing block The size of the at least one processing block may be determined, and the size of the processing block may be an integer multiple of the reference encoding unit.

According to one embodiment, the video decoding apparatus 100 may determine the size of the processing blocks 2302 and 2312 included in the picture 2300. For example, the video decoding apparatus 100 may determine the size of the processing block based on information on the size of the processing block obtained from the bitstream. Referring to FIG. 23, the video decoding apparatus 100 according to an exemplary embodiment of the present invention has a horizontal size of the processing blocks 2302 and 2312 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 video 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 of the processing blocks 2302 and 2312 included in the picture 2300 based on the size of the processing block, and may include in the processing blocks 2302 and 2312 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 embodiment, the video 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 an embodiment, the video decoding apparatus 100 may acquire information on a determination order of a reference encoding unit from a bitstream for each specific data unit. For example, the acquiring unit 105 can acquire information on the order of determination of the 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 video decoding apparatus 100 may determine at least one reference encoding unit based on the determined order according to an embodiment.

According to one embodiment, the acquiring unit 105 may acquire information on the reference encoding unit determination order from the bitstream as information related to the processing blocks 2302 and 2312, and the video decoding apparatus 100 may acquire information It is possible to determine the order of determining at least one reference encoding unit included in the

pictures

2302 and 2312 and determine at least one reference encoding unit included in the picture 2300 according to the determination order of the encoding units. Referring to FIG. 23, the video decoding apparatus 100 can determine the

determination order

2304 and 2314 of at least one reference encoding unit associated with each

processing block

2302 and 2312. For example, when information on a determination order of reference encoding units is obtained for each processing block, the reference encoding unit determination order associated with each

processing block

2302, 2312 may be different for each processing block. When the reference encoding unit determination order 2304 related to the processing block 2302 is a raster scan order, the reference encoding unit included in the processing block 2302 can be determined according to the raster scan order. On the other hand, when the reference encoding unit determination order 2314 related to the other processing block 2312 is in the reverse order of the raster scan order, the reference encoding unit included in the processing block 2312 can be determined according to the reverse order of the raster scan order.

The video decoding apparatus 100 may decode the determined at least one reference encoding unit according to an embodiment. The video 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 embodiment, the video decoding apparatus 100 may obtain block type information indicating a type of a current encoding unit or division type information indicating a method of dividing a current encoding unit from a bitstream. The block type information or the division type information may be included in a bitstream related to 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 information included in the segment header can be used. Further, the video decoding apparatus 100 may obtain a syntax corresponding to the maximum encoding unit, the reference encoding unit, and the block type information or the division type information from the bitstream for each processing block, from the bitstream.

Various embodiments have been described above. It will be understood by those skilled in the art that the present disclosure may be embodied in various forms without departing from the essential characteristics of the present disclosure. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present disclosure is set forth in the appended claims rather than the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present disclosure.

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. The computer-readable recording medium includes a storage medium such as a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.), optical reading medium (e.g., CD ROM,

Claims

Determining a rectangular scan area including all effective transform coefficients in a current block;

Scanning information on the transform coefficients in the quadrangular scan area according to a predetermined scan order; And

Obtaining transform coefficients of the current block based on information about the scanned transform coefficients;

Performing inverse quantization and inverse transform on the transform coefficients of the current block to generate a residual block of the current block; And

And reconstructing a current block based on the generated residual block.
The method according to claim 1,

Wherein the rectangular scan area includes all effective transformation coefficients in the current block,

Wherein the remaining region in the current block excluding the square scan region includes only a transform coefficient having a value of 0 instead of an effective transform coefficient.
The method according to claim 1,

Wherein the step of determining the rectangular scan area comprises:

Obtaining information on coordinates specifying the quadrangular scan area from a bitstream; And

Determining a quadrangular scan area including all effective transformation coefficients in a current block based on information on coordinates specifying the quadrangular scan area,

Wherein the coordinates specifying the quadrangular scan area represent a horizontal coordinate for an effective transformation coefficient located at the rightmost position in the current block and a vertical coordinate for an effective transformation coefficient located at the lowermost position in the current block, Video decoding method.
The method of claim 3,

Wherein the step of acquiring information on coordinates specifying the quadrangular scan area from a bitstream comprises:

Performing binary arithmetic decoding based on the context model on information about coordinates specifying the rectangular scan area; And

Further comprising the step of performing inverse binarization using the inverse binarization method on the binary arithmetic decoding information to obtain inverse binarization information on the coordinates specifying the quadrangular scan area.
5. The method of claim 4,

Wherein the context model is determined based on at least one of a size of the current block, a color component of the current block, and a bin index.
5. The method of claim 4,

Wherein the predetermined inverse binarization method is at least one of a fixed length inverse binarization method and a truncated unary inverse binarization method.
The method according to claim 1,

Wherein the predetermined scanning order is a sequence according to an inverse zig-zag scan or a sequence according to an inverse diagonal scan.
The method of claim 3,

Wherein the predetermined scanning order is determined based on at least one of a horizontal direction coordinate of the effective conversion coefficient pixel located at the rightmost position in the current block and a vertical direction coordinate of the effective conversion coefficient pixel located at the lowermost position in the current block Wherein the video decoding method comprises the steps of:
The method according to claim 1,

The information on the transform coefficients may be,

A flag information indicating whether an absolute value of the transform coefficient is larger than a predetermined value, remaining level information about an absolute value of the transform coefficient, sign information of the transform coefficient, And binarization parameter information,

Wherein the predetermined value is at least one of 0, 1, and 2.
The method according to claim 1,

Wherein obtaining the transform coefficients of the current block based on the information about the scanned transform coefficients comprises:

And performing binary arithmetic decoding and inverse binarization based on the context model on flag information indicating whether the absolute value of the transform coefficients is larger than a predetermined value to obtain transform coefficients of the current block .
10. The method of claim 9,

Wherein the flag information indicating whether the absolute value of the transform coefficients is larger than a predetermined value includes a first transform coefficient,

Wherein the context model of flag information indicating whether the absolute value of the first transform coefficient is larger than a predetermined value includes information on at least one second transform coefficient previously scanned in accordance with the predetermined scan order, At least one of a position and a color component of the first transformation coefficient, information on the right or lower peripheral transformation coefficient, and a scan position of the first transformation coefficient, a relative position in the scan region of the first transformation coefficient, Is determined on the basis of the motion vector.
The method according to claim 1,

Wherein the information on the transform coefficients includes flag information indicating whether the absolute value of the transform coefficient is larger than a predetermined value,

Wherein a maximum count of the flag information that can be obtained from the bitstream is determined based on the size of the scan area.
The method according to claim 1,

A scan order of each of the transform coefficients in the rectangular scan region is determined according to a predetermined scan order,

Wherein the step of scanning the information on the transform coefficients in the quadrangular scan area according to a predetermined scan order comprises:

And scanning the information on the transform coefficients in the quadrangular scan area according to the scan order of each transform coefficients in the quadrangle scan area.
The method according to claim 1,

At least one coefficient group including a predetermined plurality of transform coefficients in the rectangular scan region is determined according to a predetermined forward scan order,

Wherein whether to hide information on the code of at least one transform coefficient is determined for each coefficient group unit.
Obtaining transform coefficients of a current block;

Determining a rectangular scan area including all the effective transform coefficients in the current block;

Scanning the information on the transform coefficients included in the quadrangular scan area according to a predetermined scan order;

Generating entropy-encoded information by entropy encoding based on the information about the scanned transform coefficients; And

And generating a bitstream including the entropy-encoded information.