WO2019088700A1 - Image encoding method and device and image decoding method and device - Google Patents

Abstract

Disclosed is an image decoding method comprising: acquiring information on a transform coefficient of a current block from a bitstream; determining a filter to be used for a current sample on the basis of at least one of the distance between the current sample and a reference sample in the current block and the size of the current block; acquiring a prediction block of the current block that includes a prediction sample of the current sample, generated using the determined filter; acquiring a residual block of the current block on the basis of the acquired information on the transform coefficient of the current block; and reconstructing the current block on the basis of the prediction block of the current block and the residual block of the current block.

Description

Image coding method and apparatus, image decoding method and apparatus

The method and apparatus according to an exemplary embodiment may encode or decode an image using various types of encoding units included in an image. The method and apparatus according to one embodiment includes an intra prediction method and apparatus.

[0003] As the development and dissemination of hardware capable of reproducing and storing high-resolution or high-definition video content, a need for a codec for effectively encoding or decoding high-resolution or high-definition video content is increasing. The encoded image content can be reproduced by being decoded. Recently, methods for efficiently compressing such high-resolution or high-definition image content have been implemented. For example, an efficient image compression method through a process of processing an image to be encoded in an arbitrary manner has been implemented.

Various data units may be used to compress the image and there may be a containment relationship between these data units. In order to determine the size of a data unit used for such image compression, a data unit can be divided by various methods, and an optimized data unit is determined according to characteristics of an image, so that an image can be encoded or decoded.

According to an embodiment of the present invention, there is provided an image decoding method, comprising: obtaining information on a transform coefficient of a current block from a bitstream; Determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block; Obtaining a prediction block of a current block including prediction samples of the current sample generated using the determined filter; Acquiring a residual block of the current block based on information on a transform coefficient of the obtained current block; And reconstructing the current block based on the prediction block of the current block and the residual block of the current block.

Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block comprises: Determining a type of filter used for the current sample and a coefficient of the filter based on at least one of the size of the block.

The type of the filter may be a low pass filter, a Gaussian filter, a bilateral filter, a uniform filter, a bilinear interpolation filter, a cubic filter a cubic filter, and a discrete cosine transform (DCT) filter.

The number of taps of the filter used in the current sample may be a predetermined value or may be determined based on at least one of the distance between the current sample and the reference sample and the size of the current block. The predetermined value may be an integer of 4 or more.

Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block comprises: Determining a plurality of filters for the current block based on at least one of a distance between the current block and the current block; And determining a filter corresponding to the current sample among the plurality of filters for the current block.

Wherein the step of determining a plurality of filters for the current block based on at least one of a size of the current block and a distance between a sample in the current block and a reference sample includes determining a height or a width of the current block, And determining a plurality of filters for the current block based on a ratio of the distance between the reference samples.

Wherein the step of determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block includes: Determining a first reference sample corresponding to the sample; Determining a plurality of filters for the current block based on a distance between the sample and a first reference sample; And determining a filter corresponding to the current sample among the plurality of filters for the current block.

Wherein the step of determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block comprises: Determining a number of filters and determining a filter for the current block corresponding to the number of filters; And determining a filter to be used for the current sample among the filters for the current block based on at least one of the distance between the current sample and the reference sample and the size of the current block.

Wherein the step of determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block is performed based on at least one of an intra prediction mode of the current block, and determining a filter to be used for the current sample based further on at least one of the at least one shape.

Determining a filter to be used for the current sample based further on at least one of an intra prediction mode of the current block and a shape of the current block,

Determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block if the intra prediction mode of the current block is a predetermined intra prediction mode . ≪ / RTI >

Wherein determining a filter to be used for the current sample based further on at least one of an intra prediction mode of the current block and a shape of the current block,

If the width of the current block is less than or equal to a predetermined first value and the height of the current block is less than or equal to a predetermined second value, a distance between a current sample and a reference sample in the current block, And determining a filter to be used for the current sample based on at least one of:

Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block is performed such that the distance between the current sample and the reference sample is less than a predetermined value Determining a first filter for the current sample and determining a second filter for the current sample if the distance between the current sample and the reference sample is greater than a predetermined value, The smoothing strength of the second filter may be less than the smoothing strength of the second filter.

The method includes determining a filter used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block; Generating a prediction block of a current block including prediction samples of the current sample generated using the determined filter; And encoding the information on the transform coefficients of the current block based on the prediction block of the current block.

An image decoding apparatus according to an embodiment obtains information on a transform coefficient of a current block from a bitstream and calculates a transform coefficient of the current block based on at least one of a distance between a current sample in the current block and a reference sample, Determining a filter to be used, obtaining a prediction block of a current block including prediction samples of the current sample generated by using the determined filter, And a processor for restoring the current block based on the prediction block of the current block and the residual block of the current block.

The computer program for the image decoding method according to an embodiment of the present disclosure can be recorded in a computer-readable recording medium.

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

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

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

FIG. 1D shows a block diagram of an image decoding apparatus according to various embodiments.

FIG. 2A shows a block diagram of an image encoding apparatus according to various embodiments.

FIG. 2B shows a flowchart of the image encoding method according to various embodiments.

FIG. 2C shows a block diagram of an image decoding unit according to various embodiments.

FIG. 2D illustrates a block diagram of an image encoding apparatus according to various embodiments.

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

FIG. 4 illustrates a process in which an image decoding apparatus determines at least one encoding unit by dividing a non-square encoding unit according to an embodiment.

FIG. 5 illustrates a process in which an image decoding apparatus divides an encoding unit based on at least one of block type information and split mode mode information according to an embodiment.

FIG. 6 illustrates a method for an image decoding apparatus to determine a predetermined encoding unit among odd number of encoding units according to an embodiment.

FIG. 7 illustrates a sequence in which a plurality of coding units are processed when an image decoding apparatus determines a plurality of coding units by dividing a current coding unit according to an exemplary embodiment.

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

FIG. 9 illustrates a process in which an image decoding apparatus determines at least one encoding unit by dividing a first encoding unit according to an embodiment.

FIG. 10 illustrates a case where the second encoding unit is limited in a case where the non-square type second encoding unit determined by dividing the first encoding unit by the image decoding apparatus satisfies a predetermined condition according to an embodiment Lt; / RTI >

FIG. 11 illustrates a process in which an image decoding apparatus divides a square-shaped encoding unit when the split mode information can not be divided into four square-shaped encoding units according to an embodiment.

FIG. 12 illustrates that the processing order among a plurality of coding units may be changed according to a division process of a coding unit according to an exemplary embodiment.

FIG. 13 illustrates a process of determining the depth of an encoding unit according to a change in type and size of an encoding unit when a plurality of encoding units are determined by recursively dividing an encoding unit according to an embodiment.

FIG. 14 illustrates a depth index (hereinafter referred to as a PID) for classifying a depth and a coding unit that can be determined according to the type and size of coding units according to an exemplary embodiment.

FIG. 15 illustrates 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. 16 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.

17 is a view for explaining intra prediction modes according to an embodiment.

18 illustrates a method of generating a prediction sample of a current sample using another filter based on at least one of a distance between a current sample and a reference sample and a size of a current block, according to one embodiment of the present disclosure Fig.

FIG. 19 is a diagram illustrating an example of a case where a negative (double) convolution order between coding units is determined in a forward or backward direction on the basis of an encoding order flag according to an embodiment of the present disclosure, Lt; / RTI > can be used for intra prediction.

A video decoding method according to various embodiments includes obtaining information on a transform coefficient of a current block from a bitstream; Determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block; Obtaining a prediction block of a current block including prediction samples of the current sample generated using the determined filter; Acquiring a residual block of the current block based on information on a transform coefficient of the obtained current block; And reconstructing the current block based on the prediction block of the current block and the residual block of the current block.

The video encoding method according to various embodiments includes determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block; Generating a prediction block of a current block including prediction samples of the current sample generated using the determined filter; And encoding the information on the transform coefficients of the current block based on the prediction block of the current block.

A video decoding apparatus in accordance with various embodiments obtains information about the transform coefficients of a current block from a bitstream and determines a transform coefficient of the current block based on at least one of a distance between a current sample in the current block and a reference sample, Determining a filter to be used, obtaining a prediction block of a current block including prediction samples of the current sample generated by using the determined filter, And a processor for restoring the current block based on the prediction block of the current block and the residual block of the current block.

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

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

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

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

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

When an element is referred to as " including " an element throughout the specification, it is to be understood that the element may include other elements as well, without departing from the spirit or scope of the present invention.

In addition, the term " part " used in the specification means software or hardware component, and " part " However, " part " is not meant to be limited to software or hardware. &Quot; Part " may be configured to reside on an addressable storage medium and may be configured to play back one or more processors. Thus, by way of example, and not limitation, " part (s) " refers to components such as software components, object oriented software components, class components and task components, and processes, Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. The functions provided in the components and " parts " may be combined into a smaller number of components and " parts " or further separated into additional components and " parts ".

In accordance with one embodiment of the present disclosure, " part " may be embodied in a processor and memory. The term " processor " should be broadly interpreted to include a general purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, In some circumstances, a " processor " may refer to an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA) The term " processor " refers to a combination of processing devices, such as, for example, a combination of a DSP and a microprocessor, a combination of a plurality of microprocessors, a combination of one or more microprocessors in conjunction with a DSP core, It can also be called.

The term " memory " should be broadly interpreted to include any electronic component capable of storing electronic information. The terminology memory may be any suitable memory such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erase- May refer to various types of processor-readable media such as erasable programmable read-only memory (PROM), flash memory, magnetic or optical data storage devices, registers, and the like. A memory is said to be in electronic communication with a processor if the processor can read information from and / or write information to the memory. The memory integrated in the processor is in electronic communication with the processor.

Hereinafter, the " image " may be a static image such as a still image of a video or a dynamic image such as a moving image, i.e., the video itself.

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

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

An image encoding apparatus, an image decoding apparatus, an image encoding method, and an image decoding method will be described below with reference to FIGS. 1 to 19, according to an embodiment. A method of determining a data unit of an image according to one embodiment will be described with reference to Figs. 3 to 16, and the distance from the reference sample and the current A method and apparatus for encoding or decoding an image are described which determine a filter based on at least one of the size of a block and adaptively perform intra prediction using a determined filter.

Hereinafter, a method and apparatus for encoding / decoding an image for adaptively performing intraprediction based on various types of encoding units according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG.

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

The image decoding apparatus 100 according to various embodiments may include an acquisition unit 105, an intra prediction unit 110, and an image decoding unit 115.

The acquisition unit 105, the intra prediction unit 110, and the image decoding unit 115 may include at least one processor. The acquisition unit 105, the intra prediction unit 110, and the image decoding unit 115 may include a memory for storing instructions to be executed by at least one processor. The image decoding unit 115 may be implemented in hardware separate from the acquisition unit 105 and the intra prediction unit 110 or may include an acquisition unit 105 and an intra prediction unit 110. [

The obtaining unit 105 may obtain information on the transform coefficient of the current block from the bitstream. The obtaining unit 105 may obtain information on the prediction mode of the current block from the bitstream and information on the intra prediction mode of the current block.

The acquiring unit 105 may include information indicating a prediction mode of the current block, which indicates an intra mode or an inter prediction mode. The information on the intra prediction mode of the current block may be information on the intra prediction mode applied to the current block among the plurality of intra prediction modes. For example, the intra-prediction mode may be one of at least one angular mode having a DC mode, a planar mode, and a prediction direction. The angular mode includes a horizontal mode, a vertical mode, and a diagonal mode, and may include a mode having a predetermined direction except for the horizontal direction, the vertical direction, and the diagonal direction. For example, the number of angular modes may be 65 or 33.

The intra prediction unit 110 can be activated when the prediction mode of the current block is the intra prediction mode.

The intra prediction unit 110 may perform intra prediction on the current block based on the intra prediction mode of the current block. The intra predictor 110 determines a reference sample for the current sample among the reference samples based on the position of the current sample in the current block and the intra prediction mode of the current block, A predicted sample value can be generated. At this time, the reference sample may include a sample of the left or upper reference line adjacent to the current block. The reference sample for the current sample may include a surrounding sample of at least one current block of samples on the left or upper reference line of the current block. If there is one reference sample for the current sample, the intra prediction unit 110 may generate a predicted sample value of the current sample using the reference sample. On the other hand, when there are two or more reference samples for the current sample, the intra prediction unit 110 may apply a filter to the sample values of two or more reference samples for the current sample to generate a prediction sample of the current sample. At this time, the coefficient of the filter may be an integer. Scaling of the coefficients of the filter is performed and coefficients of the scaled filter may be used to determine the coefficients of the filter as integers. If scaling is performed on the coefficients of the filter and the coefficients of the scaled filter are used, the process of descaling as much as the coefficients of the filter are scaled can be performed later. The accuracy of the filter may be 1/32 of the fractional accuracy.

The intra predictor 110 may determine a filter to be used for the current sample based on at least one of the size of the current block and the distance between the current sample and the reference sample. The intra predictor 110 determines at least one filter candidate that can be applied to the current sample, and determines at least one of the at least one filter candidate based on at least one of the distance between the current sample and the reference sample in the current block, The filter used in the sample can be determined. The distance between the current sample and the reference sample may be the distance between the current sample and the reference sample located in the vertical direction of the current sample or the distance between the current sample and the reference sample located in the horizontal direction of the current sample, And the reference sample may correspond to the position coordinate value of the current sample in the current block. Accordingly, it can be seen that the intra predictor 110 determines the filter used for the current sample based on at least one of the size of the current block and the distance between the current sample and the reference sample.

The intra predictor 110 can determine the type of filter and coefficient of the filter used in the current sample based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block. At this time, the type of the filter may be a low pass filter, a Gaussian filter, a bilateral filter, a uniform filter, a bilinear interpolation filter, a cubic filter a cubic filter, a [1 2 1] filter, and a DCT (Discrete Cosine Transform) filter. In this case, the DCT filter may be a 4-tap DCT interpolation filter (DCT-IF) used for subpixel motion compensation of the chroma component. In addition, two or more filters may be combined to create a new filter, and a newly created filter may be added as a filter type. Also, without being limited to the types of filters listed above, the type of various filters may be the type of filter currently used in the sample.

The number of taps of the filter used in the current sample may be a predetermined value. At this time, the predetermined value may be four. That is, the filter used for the current sample may be a 4-tap filter. However, the present invention is not limited to this, and the predetermined value may be one of various integer values of 1 or more, preferably 2 or more.

Alternatively, the number of taps of the filter used in the current sample may be determined based on at least one of the distance between the current sample and the reference sample and the size of the current block. For example, when the distance between the current sample and the reference sample is smaller than a predetermined value, the intra prediction unit 110 can determine the number of taps of the filter as a predetermined first tap number. The intra predictor 110 can determine the number of taps of the filter as a predetermined second number of taps when the distance between the current sample and the reference sample is larger than a predetermined value. At this time, the predetermined first number of taps may be smaller than the predetermined second number of taps.

The intra predictor 110 may determine a plurality of filters for the current block based on at least one of the size of the current block and the distance between at least one sample in the current block and the reference sample. That is, the plurality of filters for the current block may include at least one filter candidate that can be used for the current sample.

The intra prediction unit 110 may determine a filter corresponding to the current sample among the plurality of filters for the current block. At this time, the intra predictor 110 calculates a ratio of the current block size (height or width) and the ratio of the distance between at least one sample in the current block and the position of the current sample in the current block (or the distance between the current sample and the reference sample) To determine a filter corresponding to a current one of a plurality of filters for a current block.

The intra prediction unit 110 can determine a first reference sample corresponding to a sample in the current block based on the intra prediction mode of the current block. For example, the intra prediction unit 110 may determine, as a first reference sample, a reference sample that intersects an extension line of the intra prediction direction by the intra prediction mode of the current block from the current sample among the reference samples. Intraprediction unit 110 may determine a plurality of filters for a current block based on a distance between a sample and a first reference sample. The intra prediction unit 110 may determine a filter corresponding to the current sample among the plurality of filters for the current block.

The intra predictor 110 may determine the number of filters used in the current block based on the size of the current block and determine a filter for the current block corresponding to the number of filters. For example, when the height or width of the current block is smaller than a predetermined value, the image decoding apparatus 100 can determine the number of filters used in the current block to be one. If the number of filters used in the current block is determined to be one, the intra prediction unit 110 can determine a filter for the current block based on the current block size and the current intra prediction mode. That is, the intra predictor 110 determines a threshold value based on the size of the current block, determines an intra prediction mode index difference value based on the index difference value between the current intra prediction mode, the vertical mode and the horizontal mode, The determined intra prediction mode index difference value may be compared with a threshold value to determine a filter for the current block.

Alternatively, when the value of the index of the intra prediction mode of the current block is an odd number, the intra prediction unit 110 may determine the first filter as a filter for the current block. If the intra prediction mode value of the current block is an even value , The second filter can be determined as a filter for the current block.

The intra predictor 110 can determine a range of the distance between the sample to which each filter is applied and the reference sample based on the size of the current block. For example, if the height and width of the current block are all greater than or equal to 32, the distance between the sample of the current block in which the filter f0 is used and the reference sample is [0, 2) and the sample of the current block in which the filter f1 is used The distance between the reference samples is [2, 4], the distance between the sample of the current block in which the filter f2 is used and the reference sample is [4, 8], and the distance between the sample of the current block in which the filter f3 is used and the reference sample is [ ), And the distance between the sample of the current block in which the filter f4 is used and the reference sample is [16, size]. (The height of the current block is smaller than 32 or the width is smaller than 32), the distance between the sample of the current block in which the filter f0 is used and the reference sample is [0, 1), and the distance The distance between the sample of the current block in which the filter f2 is used and the reference sample is [2, 3], and the distance between the sample of the current block in which the filter f3 is used and the reference sample is [3 , 4) and the distance between the sample of the current block in which the filter f4 is used and the reference sample is [4, size].

The intra predictor 110 can determine a filter to be used for the current sample among the filters for the current block based on at least one of the distance between the current sample and the reference sample and the size of the current block.

The intra prediction unit 110 may determine a filter to be used for the current sample based on at least one of the intra prediction mode of the current block and the shape of the current block.

For example, if the intra-prediction mode of the current block is a predetermined intra-prediction mode, the intra-prediction unit 110 predicts the current sample based on at least one of the distance between the current sample in the current block and the reference sample, The filter to be used can be determined. At this time, the predetermined intra prediction mode may be one of an angular mode excluding the DC mode and the planar mode. Specifically, the predetermined intra prediction mode may be one of the remaining modes except for the diagonal modes among the angular modes.

For example, if the prediction mode of the current block is a horizontal mode or a vertical mode, the intraprediction unit 110 may add any filter (for example, an interpolation filter or [1] to the reference samples to generate prediction samples of the current block. , 2, 1] reference sample filter, and the like), it is possible to perform intra prediction. The intra prediction unit 110 performs intra prediction using the [1, 2, 1] reference sample filter to generate prediction samples of the current block when the prediction mode of the current block is a diagonal mode having an angle of multiples of 45 degrees Can be performed. The intraprediction unit 110 estimates a current block using a filter used for a current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of a current block, if the prediction mode of the current block is the remaining angular mode, Can be determined.

The intra predictor 110 calculates a filter used for the current sample based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block based on whether the current block is a square or a rectangle You can decide.

Alternatively, the intra-prediction unit 110 determines a filter used for the current sample based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block based on the ratio of the height and width of the current block .

If the width of the current block is less than or equal to a predetermined first value and the height of the current block is less than or equal to a predetermined second value, the intra predictor 110 calculates the distance between the current sample and the reference sample in the current block, The first filter used for the current sample may be determined based on at least one of the sizes of the blocks. If the width of the current block is larger than the predetermined first value or the height of the current block is larger than the predetermined second value, the intra predictor 110 calculates the distance between the current sample and the reference sample in the current block, The size of the second filter may be determined based on at least one of the sizes of the first filter and the second filter.

If the distance between the current sample and the reference sample is smaller than the predetermined value, the intra predictor 110 determines a first filter for the current sample. If the distance between the current sample and the reference sample is larger than the predetermined value, Lt; / RTI > can be determined. At this time, the smoothing strength of the first filter may be smaller than the smoothing strength of the second filter.

The intra prediction unit 110 may acquire a prediction block of the current block including the prediction sample of the current sample generated using the determined filter.

The image decoding unit 115 can obtain the residual block of the current block based on the information on the transform coefficient of the current block. That is, the image decoding unit 115 can obtain a residual sample related to the residual block of the current block by performing inverse quantization and inverse transform based on the information on the transform coefficient of the current block from the bitstream.

The image decoding unit 115 can restore the current block based on the prediction block of the current block and the residual block of the current block. The image decoding unit 115 generates a current in-block reconstruction sample using a sample value of a prediction block intra-prediction block of the current block and a residual value of a residual sample in a residual block of the current block, It is possible to generate a restoration block of the block.

On the other hand, the video decoding apparatus 100 determines the filter used for the current sample based on at least one of the size of the current block and the distance between the current sample and the reference sample, and outputs flag information indicating whether to perform adaptive intra prediction And determine whether to determine a filter to be used for the current sample based on at least one of the size of the current block and the distance between the current and reference samples based on the flag information. At this time, the flag information may be obtained for each block, and in particular, for each maximum encoding unit. Or may be obtained frame by frame.

Also, the image decoding apparatus 100 can obtain flag information commonly applied to the luminance component and the chrominance component. Alternatively, the image decoding apparatus 100 may obtain flag information that is applied to each of the luminance component or the chrominance component

The image decoding apparatus 100 may determine a filter set that is commonly applied to the luminance component and the chrominance component. Alternatively, the image decoding apparatus 100 may determine a filter set to be applied to each component.

Alternatively, the video decoding apparatus 100 determines whether to determine a filter used for the current sample based on at least one of the size of the current block and the distance between the current sample and the reference sample, without obtaining flag information from the bitstream . For example, when the prediction mode of the current block is a predetermined intra-prediction mode, the image decoding apparatus 100 determines whether or not the filter used for the current sample based on at least one of the size of the current block and the distance between the current sample and the reference sample And decide to perform intra prediction in an adaptive manner.

Alternatively, the video decoding apparatus 100 may determine whether to perform intra-prediction adaptively based on the weight of the filtering reference samples and the filter using the information of the neighboring blocks without obtaining the flag information from the bit stream. For example, the image decoding apparatus 100 may calculate a filter used for a first sample in a neighboring block based on a size of a neighboring block and a distance between a first sample and a reference sample in the neighboring block, Based on the flag information of a neighboring block indicating whether intraprediction is to be performed adaptively based on the filter used for the first sample in the neighboring block, at least one of the size of the at least one current block and the distance between the current sample and the reference sample And determine whether to determine a filter to be used for the current sample based on the one. Alternatively, the video decoding apparatus 100 determines a filter used for the current sample based on at least one of the size of the current block and the distance between the current sample and the reference sample if the size of the current block is a predetermined first block size And perform intra prediction based on the filter used in the current sample. The image decoding apparatus 100 can perform the conventional intra prediction without determining the filter used for the current sample based on the size of the current block and the distance between the current sample and the reference sample have.

The image decoding apparatus 100 determines a filter to be used for a current sample based on at least one of a size of a current block and a distance between a current sample and a reference sample, It is possible to perform intraprediction by combining intraprediction subdecryption tools similar to a decryption tool. Alternatively, the video decoding apparatus 100 may assign a priority among a plurality of intra-prediction sub-decoding tools and perform intra-prediction according to the priority between the sub-decoding tools. That is, if a high-priority sub / decryption tool is used, a low priority sub / decryption tool may not be used, and if a high priority sub / decryption tool is not used, / RTI > can be used.

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

In step S105, the image decoding apparatus 100 can obtain information on the transform coefficients of the current block from the bitstream.

In step S110, the image decoding apparatus 100 may determine a filter to be used for the current sample based on at least one of the distance between the current sample in the current block and the reference sample and the size of the current block.

In step S115, the image decoding apparatus 100 may obtain a prediction block of a current block including a prediction sample of a current sample generated using the determined filter.

In step S120, the image decoding apparatus 100 can obtain the residual block of the current block based on the information on the transform coefficient of the current block.

In step S125, the image decoding apparatus 100 can restore the current block based on the prediction block and the residual block of the current block.

1C 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 the image decoding unit 115 of the image decoding apparatus 100. [

Referring to FIG. 1C, 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 intra prediction unit 6400 performs intra prediction on a block-by-block basis. The intra prediction unit 6400 of FIG. 1C may correspond to the intra prediction unit 110 of FIG. 1A.

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 is restored by adding the predictive data and residue data for each block generated by the intra predictor 6400 or the inter predictor 6350 and the deblocking block 6450 and The SAO performing unit 6500 performs loop filtering on the data of the reconstructed spatial region and outputs 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 image data in a decoding unit (not shown) of the image decoding apparatus 100, the stepwise operations of the image decoding unit 6000 according to various embodiments may be performed on a block-by-block basis.

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

The image decoding apparatus 100 according to an exemplary embodiment may include a memory 120 and at least one processor 125 connected to the memory 120. [ The operations of the image decoding apparatus 100 according to an embodiment may be operated as individual processors or may be operated under the control of a central processor. In addition, the memory 120 of the video decoding apparatus 100 can store data received from the outside and data generated by the processor. The processor 125 of the video decoding apparatus 100 obtains information on the current block from the bitstream, and uses the current block based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block Obtains a prediction block of the current block including the predicted sample of the current sample generated using the determined filter, obtains a residual block of the current block based on the information on the transform coefficient of the current block , The current block can be restored based on the prediction block and the residual block of the current block.

FIG. 2A shows a block diagram of an image encoding apparatus according to various embodiments.

The image encoding apparatus 150 according to various embodiments may include an intra prediction unit 155 and an image encoding unit 160.

The intra prediction unit 155 and the image encoding unit 160 may include at least one processor. The intra prediction unit 155 and the image encoding unit 160 may include a memory for storing instructions to be executed by at least one processor. The intra prediction unit 155 and the image encoding unit 160 may be implemented separately from the intra prediction unit 155 and the image encoding unit 160 or may include the intra prediction unit 155 and the image encoding unit 160.

The intra predictor 155 can determine a filter used in the current sample based on at least one of the distance between the current sample in the current block and the reference sample and the size of the current block.

The intra prediction unit 155 may generate a prediction block of the current block including the prediction sample of the current sample generated using the filter used in the current sample.

The intraprediction unit 155 can determine the type of the filter and coefficient of the filter used in the current sample based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block.

The number of taps of the filter used in the current sample may be a predetermined value. At this time, the predetermined value may be an integer of 4 or more. Alternatively, the number of taps of the filter used in the current sample may be determined based on at least one of the distance between the current sample and the reference sample and the size of the current block.

The intra predictor 155 can determine a plurality of filters for the current block based on at least one of the size of the current block and the distance between the sample in the current block and the reference sample.

The intra prediction unit 155 may determine a filter corresponding to the current sample among the plurality of filters for the current block.

The intra prediction unit 155 can determine the first reference sample corresponding to the intra-block sample based on the intra prediction mode of the current block. The intra prediction unit 155 may determine a plurality of filters for the current block based on the distance between the sample in the current block and the first reference sample. The intra prediction unit 155 may determine a filter corresponding to the current sample among the plurality of filters for the current block.

The intraprediction unit 155 determines the number of filters used in the current block based on the size of the current block and determines a filter for the current block corresponding to the number of the filters. Based on at least one of the distance between the reference sample and the reference sample and the size of the current block.

If the intra prediction mode of the current block is a predetermined intra prediction mode, the intra prediction unit 155 predicts the filter used for the current sample based on at least one of the distance between the current sample in the current block and the reference sample and the size of the current block You can decide.

If the distance between the current sample and the reference sample is smaller than a predetermined value, the intra prediction unit 155 determines a first filter for the current sample. If the distance between the current sample and the reference sample is larger than a predetermined value, Lt; / RTI > can be determined. At this time, the smoothing intensity of the first filter may be smaller than the smoothing intensity of the second filter.

The image encoding unit 160 can encode information on the transform coefficients of the current block based on the prediction block of the current block. That is, the image encoding unit 160 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, transforms and quantizes the residual block of the current block, Can be encoded. The image encoding unit 160 may encode information on the prediction mode of the current block and information on the intra prediction mode of the current block.

The image encoding unit 160 may generate a bitstream including information on the transform coefficients of the current block and output the bitstream.

FIG. 2B shows a flowchart of the image encoding method according to various embodiments.

In operation S150, the image encoding apparatus 150 may determine a filter to be used for the current sample based on at least one of the distance between the current sample and the reference sample and the size of the current block.

In operation S155, the image encoding apparatus 150 may generate a prediction block of a current block including a prediction sample of a current sample generated using the determined filter. In step S160, the image encoding apparatus 150 can encode information on the transform coefficients of the current block based on the prediction block of the current block.

FIG. 2C 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 the image encoding unit 160 of the image 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 the quantization unit 7300 may perform conversion and quantization on the residue data to output the transform coefficients quantized on a block-by-block basis. The intra prediction unit 7200 of FIG. 2C corresponds to the intra prediction unit 155 of FIG. 2A .

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.

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

FIG. 2D illustrates a block diagram of an image encoding apparatus 150 according to an embodiment.

The image encoding apparatus 150 according to an embodiment may include at least one processor 170 connected to the memory 165 and the memory 165. The operations of the image encoding apparatus 150 according to one embodiment may operate as separate processors or may be operated under the control of a central processor. In addition, the memory 165 of the image encoding apparatus 150 can store data received from the outside and data generated by the processor.

The processor 170 of the image encoding apparatus 150 determines a filter to be used for the current sample based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block, A prediction block of the current block including the prediction sample of the current sample is generated and the information on the transform coefficient of the current block is encoded based on the prediction block of the current block.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The encoding unit may be less than or equal to the maximum encoding unit. For example, the maximum encoding unit is also one of the encoding units since it is the encoding unit having the maximum size. When the division type mode information for the maximum encoding unit indicates that the information is not divided, the encoding unit determined in the maximum encoding unit has the same size as the maximum encoding unit. If the division type mode information for the maximum encoding unit indicates division, the maximum encoding unit may be divided into encoding units. In addition, if division type mode information for an encoding unit indicates division, encoding units can be divided into smaller-sized encoding units. However, the division of the image is not limited to this, and the maximum encoding unit and the encoding unit may not be distinguished. The division of encoding units will be described in more detail with reference to FIG. 3 to FIG.

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

The shapes and sizes of the transform block and the prediction block may not be related to each other.

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

The division of encoding units will be described in more detail with reference to FIG. 3 to FIG. The current block and the neighboring blocks of the present disclosure may represent one of a maximum encoding unit, an encoding unit, a prediction block, and a transform block. In addition, the current block or the current encoding unit is a block in which decoding or encoding is currently proceeding, or a block in which the current segmentation is proceeding. The neighboring block may be a block restored before the current block. The neighboring blocks may be spatially or temporally contiguous from the current block. The neighboring block may be located at one of the left lower side, the left side, the upper left side, the upper side, the upper right side, the right side, and the lower right side of the current block.

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

The block shape may include 4Nx4N, 4Nx2N, 2Nx4N, 4NxN, Nx4N, 32NxN, Nx32N, 16NxN, Nx16N, 8NxN, or Nx8N. Where N may be a positive integer. The block type information is information indicating at least one of a ratio, or a size, of a shape, direction, width, and height of an encoding unit.

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

When the width and height of the encoding unit are different (i.e., the block type of the encoding unit is 4Nx2N, 2Nx4N, 4NxN, Nx4N, 32NxN, Nx32N, 16NxN, Nx16N, 8NxN, or Nx8N), the image decoding apparatus 100 The block type information of the encoding unit can be determined as a non-square. When the shape of the coding unit is a non-square shape, the image decoding apparatus 100 sets the width and height ratio of the block type information of the coding unit to 1: 2, 2: 1, 1: 4, 4: , 8: 1, 1:16, 16: 1, 1:32, 32: 1. Further, based on the length of the width of the coding unit and the length of the height, the video decoding apparatus 100 can determine whether the coding unit is the horizontal direction or the vertical direction. Further, the image decoding apparatus 100 can determine the size of the encoding unit based on at least one of the width of the encoding unit, the length of the height, and the width.

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

The image decoding apparatus 100 can obtain the split mode information from the bit stream. However, the present invention is not limited thereto, and the image decoding apparatus 100 and the image encoding apparatus 150 can determine the promised divided mode information based on the block type information. The video decoding apparatus 100 can determine the promised divided mode mode information for the maximum encoding unit or the minimum encoding unit. For example, the image decoding apparatus 100 may determine the division type mode information as a quad split with respect to the maximum encoding unit. Also, the video decoding apparatus 100 can determine the division type mode information to be " not divided " for the minimum encoding unit. Specifically, the image decoding apparatus 100 can determine the size of the maximum encoding unit to be 256x256. The video decoding apparatus 100 can determine the promised division mode information in advance by quad division. Quad partitioning is a split mode mode that bisects both the width and the height of the encoding unit. The image decoding apparatus 100 can obtain a 128x128 encoding unit from the 256x256 maximum encoding unit based on the division type mode information. Also, the image decoding apparatus 100 can determine the size of the minimum encoding unit to be 4x4. The image decoding apparatus 100 can obtain the division type mode information indicating " not divided " for the minimum encoding unit.

According to one embodiment, the image decoding apparatus 100 may use block type information indicating that the current encoding unit is a square type. For example, the image decoding apparatus 100 can determine whether to divide a square encoding unit according to division type mode information, vertically or horizontally, four encoding units, or the like. 3, if the block type information of the current encoding unit 300 indicates a square shape, the decoding unit 120 decodes the same size as the current encoding unit 300 according to the split mode mode information indicating that the current block is not divided 310c, 310d, 310e, 310f, etc.) based on the division type mode information indicating the predetermined division method without dividing the coding unit 310a having the division type mode information 310b, 310c, 310d, 310e, 310f or the like.

Referring to FIG. 3, the image decoding apparatus 100 includes two encoding units 310b, which are obtained by dividing a current encoding unit 300 in the vertical direction, based on division mode information indicating that the image is divided vertically according to an embodiment You can decide. The image decoding apparatus 100 can determine two encoding units 310c in which the current encoding unit 300 is divided in the horizontal direction based on the division type mode information indicating that the image is divided in the horizontal direction. The image decoding apparatus 100 can determine four coding units 310d in which the current coding unit 300 is divided into the vertical direction and the horizontal direction based on the division type mode information indicating that the image is divided into the vertical direction and the horizontal direction. The image decoding apparatus 100 includes three encoding units 310e obtained by dividing the current encoding unit 300 in the vertical direction on the basis of the division mode mode information indicating that the image is divided ternary in the vertical direction according to an embodiment You can decide. The image decoding apparatus 100 can determine the three encoding units 310f in which the current encoding unit 300 is divided in the horizontal direction based on the division mode mode information indicating that the image is divided tangentially in the horizontal direction. However, a division type in which a square coding unit can be divided should not be limited to the above-described type, and various types of division mode information can be included. The predetermined divisional form in which the square encoding unit is divided will be described in detail by way of various embodiments below.

FIG. 4 illustrates a process in which the image decoding apparatus 100 determines at least one encoding unit by dividing a non-square encoding unit according to an embodiment.

According to an embodiment, the image decoding apparatus 100 may use block type information indicating that the current encoding unit is a non-square format. The image decoding apparatus 100 may determine whether to divide the non-square current encoding unit according to the division mode mode information or not in a predetermined method. 4, if the block type information of the current encoding unit 400 or 450 indicates a non-square shape, the image decoding apparatus 100 determines whether the current encoding unit 440a, 440a, 440a, 440a, 440a, 440a, 440a, 440a, 440a, 440a, 440a, 440a, 440a, , 470b, 480a, 480b, 480c. The predetermined division method in which the non-square coding unit is divided will be described in detail through various embodiments.

According to an exemplary embodiment, the image decoding apparatus 100 may determine the type in which the encoding unit is divided using the division type mode information. In this case, the division type mode information may include at least one of the encoding units Can be expressed. 4, when the division type mode information indicates that the current encoding unit 400 or 450 is divided into two encoding units, the image decoding apparatus 100 determines the current encoding unit 400 or 450 based on the division type mode information, 450) to determine two encoding units 420a, 420b, or 470a, 470b included in the current encoding unit.

When the video decoding apparatus 100 divides the current coding unit 400 or 450 in the form of non-square based on the division type mode information, the video decoding apparatus 100 divides the current coding unit 400 or 450 into non- The current encoding unit can be divided in consideration of the position of the long side of the encoding unit 400 or 450. [ For example, the image decoding apparatus 100 divides the current encoding unit 400 or 450 in the direction of dividing the long side of the current encoding unit 400 or 450 in consideration of the shape of the current encoding unit 400 or 450 So that a plurality of encoding units can be determined.

According to one embodiment, when the division type mode information indicates that an encoding unit is divided into an odd number of blocks (ternary division), the video decoding apparatus 100 performs an odd number encoding The unit can be determined. For example, when the division type mode information indicates that the current encoding unit 400 or 450 is divided into three encoding units, the image decoding apparatus 100 converts the current encoding unit 400 or 450 into three encoding units 430a, 430b, 430c, 480a, 480b, and 480c.

According to one embodiment, the ratio of the width and height of the current encoding unit 400 or 450 may be 4: 1 or 1: 4. If the ratio of width to height is 4: 1, the length of the width is longer than the length of the height, so the block type information may be horizontal. If the ratio of width to height is 1: 4, the block type information may be vertical because the length of the width is shorter than the length of the height. The image decoding apparatus 100 may determine to divide the current encoding unit into odd number blocks based on the division type mode information. The image decoding apparatus 100 can determine the division direction of the current encoding unit 400 or 450 based on the block type information of the current encoding unit 400 or 450. [ For example, when the current encoding unit 400 is the vertical direction, the image decoding apparatus 100 can determine the encoding units 430a, 430b, and 430c by dividing the current encoding unit 400 in the horizontal direction. Also, when the current encoding unit 450 is in the horizontal direction, the image decoding apparatus 100 can determine the encoding units 480a, 480b, and 480c by dividing the current encoding unit 450 in the vertical direction.

According to an exemplary embodiment, the image decoding apparatus 100 may determine an odd number of encoding units included in the current encoding unit 400 or 450, and the sizes of the determined encoding units may not be the same. For example, the size of a predetermined encoding unit 430b or 480b among the determined odd number of encoding units 430a, 430b, 430c, 480a, 480b, and 480c is different from the size of the other encoding units 430a, 430c, 480a, and 480c . That is, an encoding unit that can be determined by dividing the current encoding unit (400 or 450) may have a plurality of types of sizes, and an odd number of encoding units (430a, 430b, 430c, 480a, 480b, 480c) May have different sizes.

According to an exemplary embodiment, when the division type mode information indicates that an encoding unit is divided into an odd number of blocks, the image decoding apparatus 100 may determine an odd number of encoding units included in the current encoding unit 400 or 450, Furthermore, the image decoding apparatus 100 may set a predetermined restriction on at least one of the odd number of encoding units generated by division. Referring to FIG. 4, the image decoding apparatus 100 includes an encoding unit 430a, 430b, 430c, 480a, 480b, and 480c, which are generated by dividing a current encoding unit 400 or 450, The decoding process for the coding units 430b and 480b may be different from the coding units 430a, 430c, 480a, and 480c. For example, in the video decoding apparatus 100, the coding units 430b and 480b positioned at the center are restricted so as not to be further divided unlike the other coding units 430a, 430c, 480a, and 480c, It can be limited to be divided.

FIG. 5 illustrates a process in which the image decoding apparatus 100 divides an encoding unit based on at least one of block type information and split mode mode information according to an embodiment.

According to an exemplary embodiment, the image decoding apparatus 100 may determine to divide or not divide the first encoding unit 500 of a square shape into encoding units based on at least one of the block type information and the division mode mode information . According to one embodiment, when the division type mode information indicates that the first encoding unit 500 is divided in the horizontal direction, the image decoding apparatus 100 divides the first encoding unit 500 in the horizontal direction, The unit 510 can be determined. The first encoding unit, the second encoding unit, and the third encoding unit used according to an embodiment are terms used to understand the relation before and after the division between encoding units. For example, if the first encoding unit is divided, the second encoding unit can be determined, and if the second encoding unit is divided, the third encoding unit can be determined. Hereinafter, the relationship between the first coding unit, the second coding unit and the third coding unit used can be understood to be in accordance with the above-mentioned characteristic.

According to an embodiment, the image decoding apparatus 100 may determine that the determined second encoding unit 510 is not divided or divided into encoding units based on the division mode information. Referring to FIG. 5, the image decoding apparatus 100 divides a second encoding unit 510 of a non-square shape determined by dividing a first encoding unit 500 based on division type mode information into at least one third encoding 520a, 520b, 520c, 520d, etc., or the second encoding unit 510 may not be divided. The image decoding apparatus 100 can obtain the division type mode information and the image decoding apparatus 100 divides the first encoding unit 500 based on the obtained division type mode information to generate a plurality of second encoding And the second encoding unit 510 may be divided according to the manner in which the first encoding unit 500 is divided based on the division type mode information. According to one embodiment, when the first encoding unit 500 is divided into the second encoding units 510 based on the division type mode information for the first encoding unit 500, the second encoding units 510 (E.g., 520a, 520b, 520c, 520d, etc.) based on the split mode mode information for the second encoding unit 510. [ That is, the encoding unit may be recursively divided based on the division mode information associated with each encoding unit. Therefore, a square encoding unit may be determined in a non-square encoding unit, and a non-square encoding unit may be determined by dividing the square encoding unit recursively.

Referring to FIG. 5, among the odd third encoding units 520b, 520c, 520d in which the non-square second encoding unit 510 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 square-shaped third coding unit 520b, which is one of the odd-numbered third coding units 520b, 520c, and 520d, may be divided in the horizontal direction and divided into a plurality of fourth coding units. The non-square fourth encoding unit 530b or 530d, which is one of the plurality of fourth encoding units 530a, 530b, 530c, and 530d, may be further divided into a plurality of encoding units. For example, the fourth encoding unit 530b or 530d in the non-square form may be divided again into odd number of encoding units. A method which can be used for recursive division of an encoding unit will be described later in various embodiments.

According to an exemplary embodiment, the image decoding apparatus 100 may divide each of the third encoding units 520a, 520b, 520c, and 520d into encoding units based on the division type mode information. Also, the image decoding apparatus 100 may determine that the second encoding unit 510 is not divided based on the division type mode information. The image decoding apparatus 100 may divide the non-square second encoding unit 510 into odd third encoding units 520b, 520c and 520d according to an embodiment. The image decoding apparatus 100 may set a predetermined restriction on a predetermined third encoding unit among odd numbered third encoding units 520b, 520c, and 520d. For example, the image decoding apparatus 100 may limit the number of encoding units 520c located in the middle among odd numbered third encoding units 520b, 520c, and 520d to no longer be divided, or be divided into a set number of times .

Referring to FIG. 5, the image decoding apparatus 100 includes an encoding unit (not shown) located in the middle among odd third encoding units 520b, 520c, and 520d included in the second encoding unit 510 in the non- 520c may not be further divided or may be limited to being divided into a predetermined division form (for example, divided into four coding units only or divided into a form corresponding to a form in which the second coding units 510 are divided) (For example, dividing only n times, n > 0). The above restriction on the coding unit 520c positioned at the center is merely an example and should not be construed to be limited to the above embodiments and the coding unit 520c positioned at the center is not limited to the coding units 520b and 520d Quot;), < / RTI > which can be decoded differently.

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

FIG. 6 illustrates a method by which the image decoding apparatus 100 determines a predetermined encoding unit among odd number of encoding units according to an embodiment.

6, the division type mode information of the current encoding units 600 and 650 includes information on a sample at a predetermined position among a plurality of samples included in the current encoding units 600 and 650 (for example, 640, 690). However, the predetermined position in the current coding unit 600 in which at least one of the division mode information can be obtained should not be limited to the middle position shown in FIG. 6, and the predetermined position should be included in the current coding unit 600 (E.g., top, bottom, left, right, top left, bottom left, top right or bottom right, etc.) The image decoding apparatus 100 may determine division mode mode information obtained from a predetermined position and divide the current encoding unit into the encoding units of various types and sizes.

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

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

According to an exemplary embodiment, the image decoding apparatus 100 may use information indicating the positions of odd-numbered encoding units in order to determine an encoding unit located in the middle among odd-numbered encoding units. 6, the image decoding apparatus 100 divides the current encoding unit 600 or the current encoding unit 650 into odd number of encoding units 620a, 620b, 620c or odd number of encoding units 660a, 660b, and 660c. The image decoding apparatus 100 may use the information on the positions of the odd-numbered encoding units 620a, 620b, and 620c or the odd-numbered encoding units 660a, 660b, and 660c, (660b). For example, the image decoding apparatus 100 determines the positions of the encoding units 620a, 620b, and 620c based on information indicating the positions of predetermined samples included in the encoding units 620a, 620b, and 620c, The encoding unit 620b located in the encoding unit 620b can be determined. Specifically, the video decoding apparatus 100 encodes the encoding units 620a, 620b, and 620c based on information indicating the positions of the upper left samples 630a, 630b, and 630c of the encoding units 620a, 620b, and 620c, The encoding unit 620b located in the center can be determined.

Information indicating the positions of the upper left samples 630a, 630b, and 630c included in the coding units 620a, 620b, and 620c according to one embodiment is stored in the pictures of the coding units 620a, 620b, and 620c Or information about the position or coordinates of the object. Information indicating the positions of the upper left samples 630a, 630b, and 630c included in the coding units 620a, 620b, and 620c according to one embodiment is stored in the coding units 620a , 620b, and 620c, and the width or height may correspond to information indicating the difference between the coordinates of the encoding units 620a, 620b, and 620c in the picture. That is, the image decoding apparatus 100 directly uses the information on the position or the coordinates in the picture of the coding units 620a, 620b, and 620c or the information on the width or height of the coding unit corresponding to the difference value between the coordinates The encoding unit 620b located in the center can be determined.

According to one embodiment, the information indicating the position of the upper left sample 630a of the upper coding unit 620a may indicate the coordinates (xa, ya) and the upper left sample 530b of the middle coding unit 620b May indicate the coordinates (xb, yb), and the information indicating the position of the upper left sample 630c of the lower coding unit 620c may indicate the coordinates (xc, yc). The video decoding apparatus 100 can determine the center encoding unit 620b using the coordinates of the upper left samples 630a, 630b, and 630c included in the encoding units 620a, 620b, and 620c. For example, when the coordinates of the upper left samples 630a, 630b, and 630c are sorted in ascending or descending order, the coding unit 620b including (xb, yb) coordinates of the sample 630b located at the center, Can be determined as a coding unit located in the middle of the coding units 620a, 620b, and 620c determined by dividing the current coding unit 600. [ However, the coordinates indicating the positions of the samples 630a, 630b and 630c in the upper left corner may indicate the coordinates indicating the absolute position in the picture, and the position of the upper left sample 630a of the upper coding unit 620a may be (Dxb, dyb), which is information indicating the relative position of the sample 630b at the upper left of the middle encoding unit 620b, and the relative position of the sample 630c at the upper left of the lower encoding unit 620c 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 image decoding apparatus 100 may divide the current encoding unit 600 into a plurality of encoding units 620a, 620b, and 620c and may encode a predetermined one of the encoding units 620a, 620b, and 620c The encoding unit can be selected according to the criterion. For example, the image decoding apparatus 100 can select an encoding unit 620b having a different size from among the encoding units 620a, 620b, and 620c.

According to an embodiment, the image decoding apparatus 100 may include (xa, ya) coordinates, which is information indicating the position of the upper left sample 630a of the upper encoding unit 620a, a sample of the upper left sample of the middle encoding unit 620b (Xc, yc) coordinates, which is information indicating the position of the lower-stage coding unit 630b and the position of the upper-left sample 630c of the lower-stage coding unit 620c, , 620b, and 620c, respectively. The image decoding apparatus 100 encodes the encoding units 620a and 620b using the coordinates (xa, ya), (xb, yb), (xc, yc) indicating the positions of the encoding units 620a, 620b and 620c , And 620c, respectively. According to an embodiment, the image decoding apparatus 100 may determine the width of the upper encoding unit 620a as the width of the current encoding unit 600. [ The image decoding apparatus 100 can determine the height of the upper encoding unit 620a as yb-ya. The image decoding apparatus 100 may determine the width of the middle encoding unit 620b as the width of the current encoding unit 600 according to an embodiment. The image decoding apparatus 100 can determine the height of the middle encoding unit 620b as yc-yb. The image decoding apparatus 100 may determine the width or height of the lower coding unit by using the width or height of the current coding unit and the width and height of the upper coding unit 620a and the middle coding unit 620b . The image decoding apparatus 100 may determine an encoding unit having a different size from other encoding units based on the widths and heights of the determined encoding units 620a, 620b, and 620c. Referring to FIG. 6, the image decoding apparatus 100 may determine a coding unit 620b as a coding unit at a predetermined position while having a size different from that of the upper coding unit 620a and the lower coding unit 620c. However, the process of determining the encoding unit having a size different from that of the other encoding units by the video decoding apparatus 100 may be the same as that of the first embodiment in which the encoding unit of a predetermined position is determined using the size of the encoding unit determined based on the sample coordinates , Various processes may be used for determining the encoding unit at a predetermined position by comparing the sizes of the encoding units determined according to predetermined sample coordinates.

The video decoding apparatus 100 determines the position (xd, yd) which is the information indicating the position of the upper left sample 670a of the left encoding unit 660a and the position (xd, yd) of the sample 670b at the upper left of the middle encoding unit 660b 660b and 660c using the (xf, yf) coordinates, which is information indicating the (xe, ye) coordinate which is the information indicating the position of the right encoding unit 660c and the position of the sample 670c at the upper left of the right encoding unit 660c, Each width or height can be determined. The image decoding apparatus 100 encodes the encoded units 660a and 660b using the coordinates (xd, yd), (xe, ye), (xf, yf) indicating the positions of the encoding units 660a, 660b and 660c And 660c, respectively.

According to an embodiment, the image decoding apparatus 100 may determine the width of the left encoding unit 660a as xe-xd. The image decoding apparatus 100 can determine the height of the left encoding unit 660a as the height of the current encoding unit 650. [ According to an embodiment, the image decoding apparatus 100 may determine the width of the middle encoding unit 660b as xf-xe. The image decoding apparatus 100 can determine the height of the middle encoding unit 660b as the height of the current encoding unit 600. [ The image decoding apparatus 100 may determine that the width or height of the right encoding unit 660c is less than the width or height of the current encoding unit 650 and the width and height of the left encoding unit 660a and the middle encoding unit 660b . ≪ / RTI > The image decoding apparatus 100 may determine an encoding unit having a different size from the other encoding units based on the widths and heights of the determined encoding units 660a, 660b, and 660c. Referring to FIG. 6, the image decoding apparatus 100 may determine a coding unit 660b as a coding unit at a predetermined position while having a size different from that of the left coding unit 660a and the right coding unit 660c. However, the process of determining the encoding unit having a size different from that of the other encoding units by the video decoding apparatus 100 may be the same as that of the first embodiment in which the encoding unit of a predetermined position is determined using the size of the encoding unit determined based on the sample coordinates , Various processes may be used for determining the encoding unit at a predetermined position by comparing the sizes of the encoding units determined according to predetermined sample coordinates.

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

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

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

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 plurality of coding units in which the current coding unit is divided, the video decoding apparatus 100 may determine the block type information stored in the sample included in the middle coding unit, Mode information can be used.

Referring to FIG. 6, the image decoding apparatus 100 may divide the current encoding unit 600 into a plurality of encoding units 620a, 620b, and 620c based on the division type mode information, 620a, 620b, and 620c among the encoding units 620a and 620b. Furthermore, the image decoding apparatus 100 can determine the encoding unit 620b positioned at the center in consideration of the position at which the split mode information is obtained. That is, the division type mode information of the current encoding unit 600 can be obtained in the sample 640 positioned in the middle of the current encoding unit 600, and the current encoding unit 600 can be obtained based on the division type mode information In case of dividing into the plurality of encoding units 620a, 620b, and 620c, the encoding unit 620b including the sample 640 may be determined as a middle encoding unit. However, the information used for determining the coding unit located in the middle should not be limited to the division type mode information, and various kinds of information can be used in the process of determining the coding unit located in the middle.

According to an embodiment, predetermined information for identifying a coding unit at a predetermined position may be obtained from a predetermined sample included in a coding unit to be determined. Referring to FIG. 6, the image decoding apparatus 100 includes a plurality of encoding units 620a, 620b, and 620c that are determined by dividing a current encoding unit 600, Obtained from a sample at a predetermined position in the current coding unit 600 (for example, a sample located in the middle of the current coding unit 600) in order to determine the coding mode, Can be used. That is, the image decoding apparatus 100 can determine the sample at the predetermined position in consideration of the block form of the current encoding unit 600, and the image decoding apparatus 100 can determine a plurality of It is possible to determine a coding unit 620b including a sample from which predetermined information (for example, divided mode information) can be obtained among the number of coding units 620a, 620b, and 620c . Referring to FIG. 6, the image decoding apparatus 100 may determine a sample 640 located in the center of a current encoding unit 600 as a sample from which predetermined information can be obtained, The coding unit 100 may limit the coding unit 620b including the sample 640 to a predetermined limit in the decoding process. However, the position of the sample from which the predetermined information can be obtained should not be construed to be limited to the above-mentioned position, but may be interpreted as samples at arbitrary positions included in the encoding unit 620b to be determined for limiting.

The position of a sample from which predetermined information can be obtained according to one embodiment may be determined according to the type of the current encoding unit 600. [ According to one embodiment, the block type information can determine whether the current encoding unit is a square or a non-square, and determine the position of a sample from which predetermined information can be obtained according to the shape. For example, the video decoding apparatus 100 may use at least one of the information on the width of the current coding unit and the information on the height to position at least one of the width and the height of the current coding unit in half The sample can be determined as a sample from which predetermined information can be obtained. For example, when the block type information related to the current encoding unit is a non-square type, the image decoding apparatus 100 selects one of the samples adjacent to the boundary dividing the longer side of the current encoding unit into halves by a predetermined Can be determined as a sample from which the information of < / RTI >

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

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

FIG. 7 illustrates a sequence in which a plurality of coding units are processed when the image decoding apparatus 100 determines a plurality of coding units by dividing the current coding unit according to an embodiment.

The image decoding apparatus 100 may determine the second encoding units 710a and 710b by dividing the first encoding unit 700 in the vertical direction according to the division type mode information, The second encoding units 730a and 730b may be determined by dividing the first encoding unit 700 in the horizontal direction or the second encoding units 750a, 750b, 750c, and 750d by dividing the first encoding unit 700 in the vertical direction and the horizontal direction have.

Referring to FIG. 7, the image decoding apparatus 100 may determine the order in which the second encoding units 710a and 710b determined by dividing the first encoding unit 700 in the vertical direction are processed in the horizontal direction 710c . The image decoding apparatus 100 may determine the processing order of the second encoding units 730a and 730b determined by dividing the first encoding unit 700 in the horizontal direction as the vertical direction 730c. The image decoding apparatus 100 processes the encoding units located in one row of the second encoding units 750a, 750b, 750c and 750d determined by dividing the first encoding unit 700 in the vertical direction and the horizontal direction, (For example, a raster scan order or a z scan order 750e) in which the encoding units located in the next row are processed.

According to an embodiment, the image decoding apparatus 100 may recursively divide encoding units. 7, the image decoding apparatus 100 may determine a plurality of encoding units 710a, 710b, 730a, 730b, 750a, 750b, 750c and 750d by dividing the first encoding unit 700, The determined plurality of encoding units 710a, 710b, 730a, 730b, 750a, 750b, 750c, and 750d can be recursively divided. The method of dividing the plurality of encoding units 710a, 710b, 730a, 730b, 750a, 750b, 750c, and 750d may be a method corresponding to the method of dividing the first encoding unit 700. [ Accordingly, the plurality of encoding units 710a, 710b, 730a, 730b, 750a, 750b, 750c, and 750d may be independently divided into a plurality of encoding units. 7, the image decoding apparatus 100 may determine the second encoding units 710a and 710b by dividing the first encoding unit 700 in the vertical direction, and may further determine the second encoding units 710a and 710b Can be determined not to divide or separate independently.

The image decoding apparatus 100 may divide the second encoding unit 710a on the left side in the horizontal direction into the third encoding units 720a and 720b and the second encoding units 710b ) May not be divided.

According to an embodiment, the processing order of the encoding units may be determined based on the division process of the encoding units. In other words, the processing order of the divided coding units can be determined based on the processing order of the coding units immediately before being divided. The image decoding apparatus 100 can determine the order in which the third encoding units 720a and 720b determined by dividing the second encoding unit 710a on the left side are processed independently of the second encoding unit 710b on the right side. The third encoding units 720a and 720b may be processed in the vertical direction 720c because the second encoding units 710a on the left side are divided in the horizontal direction and the third encoding units 720a and 720b are determined. Since the order in which the left second encoding unit 710a and the right second encoding unit 710b are processed corresponds to the horizontal direction 710c, the third encoding unit 710a included in the left second encoding unit 710a, The right encoding unit 710b can be processed after the blocks 720a and 720b are processed in the vertical direction 720c. 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.

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

According to an embodiment, the image decoding apparatus 100 may determine that the current encoding unit is divided into odd number of encoding units based on the obtained division mode mode information. Referring to FIG. 8, the first encoding unit 800 in the form of a square may be divided into second non-square encoding units 810a and 810b, and the second encoding units 810a and 810b may be independently 3 encoding units 820a, 820b, 820c, 820d, and 820e. According to an embodiment, the image decoding apparatus 100 can determine the plurality of third encoding units 820a and 820b by dividing the left encoding unit 810a of the second encoding unit in the horizontal direction, and the right encoding unit 810b Can be divided into an odd number of third encoding units 820c, 820d, and 820e.

According to an exemplary embodiment, the image decoding apparatus 100 determines whether or not the third encoding units 820a, 820b, 820c, 820d, and 820e can be processed in a predetermined order and determines whether there are odd- You can decide. Referring to FIG. 8, the image decoding apparatus 100 may recursively divide the first encoding unit 800 to determine the third encoding units 820a, 820b, 820c, 820d, and 820e. The image decoding apparatus 100 may further include a first encoding unit 800, a second encoding unit 810a and 810b or a third encoding unit 820a, 820b, 820c , 820d, and 820e are 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 810a and 810b may be divided into odd third encoding units 820c, 820d, and 820e. The order in which the plurality of coding units included in the first coding unit 800 are processed may be a predetermined order (for example, a z-scan order 830) 100 can determine whether the third encoding units 820c, 820d, and 820e determined by dividing the right second encoding unit 810b into odd numbers satisfy the condition that the third encoding units 820c, 820d, and 820e can be processed according to the predetermined order.

According to an embodiment, the image decoding apparatus 100 satisfies a condition that third encoding units 820a, 820b, 820c, 820d, and 820e included in the first encoding unit 800 can be processed in a predetermined order And it is determined whether or not at least one of the widths and heights of the second encoding units 810a and 810b is divided in half according to the boundaries of the third encoding units 820a, 820b, 820c, 820d, and 820e, . For example, the third encoding units 820a and 820b, which are determined by dividing the height of the left second encoding unit 810a in the non-square shape by half, can satisfy the condition. The boundaries of the third encoding units 820c, 820d, and 820e determined by dividing the right second encoding unit 810b into three encoding units do not divide the width or height of the right second encoding unit 810b in half , The third encoding units 820c, 820d, and 820e may be determined as not satisfying the condition. The image decoding apparatus 100 may determine that the scan order is disconnection in the case of such unsatisfactory condition and determine that the right second encoding unit 810b is divided into odd number of encoding units based on the determination result. According to an embodiment, the image decoding apparatus 100 may limit a coding unit of a predetermined position among the divided coding units when the coding unit is divided into odd number of coding units. Since the embodiment has been described above, a detailed description thereof will be omitted.

FIG. 9 illustrates a process in which the image decoding apparatus 100 determines at least one encoding unit by dividing a first encoding unit 900 according to an embodiment.

According to an exemplary embodiment, the image decoding apparatus 100 may divide the first encoding unit 900 based on the division type mode information acquired through a receiver (not shown). The first coding unit 900 in the form of a square may be divided into four coding units having a square form, or may be divided into a plurality of non-square coding units. For example, referring to FIG. 9, when the first encoding unit 900 is square and the split mode mode information is divided into non-square encoding units, the image decoding apparatus 100 transmits the first encoding unit 900 And may be divided into a plurality of non-square encoding units. Specifically, when the division type mode information indicates that the first coding unit 900 is divided horizontally or vertically to determine an odd number of coding units, the video decoding apparatus 100 determines whether or not the first coding unit 900 can be divided into the second encoding units 910a, 910b, and 910c divided in the vertical direction as the odd number of encoding units or the second encoding units 920a, 920b, and 920c determined in the horizontal direction.

According to an embodiment, the image decoding apparatus 100 may be configured such that the second encoding units 910a, 910b, 910c, 920a, 920b, and 920c included in the first encoding unit 900 are processed in a predetermined order And the condition is that at least one of the width and the height of the first encoding unit 900 is divided in half according to the boundaries of the second encoding units 910a, 910b, 910c, 920a, 920b, and 920c . 9, the boundaries of the second encoding units 910a, 910b, and 910c, which are determined by vertically dividing the first encoding unit 900 in a square shape, are divided in half by the width of the first encoding unit 900 The first encoding unit 900 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 920a, 920b, and 920c, which are determined by dividing the first encoding unit 900 in the horizontal direction into the horizontal direction, can not divide the width of the first encoding unit 900 in half, 1 encoding unit 900 may be determined as not satisfying a condition that can be processed in a predetermined order. The image decoding apparatus 100 may determine that the scan sequence is disconnection in the case of such unsatisfactory condition and determine that the first encoding unit 900 is divided into odd number of encoding units based on the determination result. According to an embodiment, the image decoding apparatus 100 may limit a coding unit of a predetermined position among the divided coding units when the coding unit is divided into odd number of coding units. Since the embodiment has been described above, a detailed description thereof will be omitted.

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

9, the image decoding apparatus 100 may divide a first coding unit 900 in a square form and a first coding unit 930 or 950 in a non-square form into various types of coding units .

10 is a diagram illustrating a case where a second encoding unit of a non-square type determined by dividing a first encoding unit 1000 by a video decoding apparatus 100 satisfies a predetermined condition according to an embodiment, Lt; RTI ID = 0.0 > limited. ≪ / RTI >

According to an embodiment, the image decoding apparatus 100 may convert the first encoding unit 1000 in a square form into a second encoding unit 1010a in a non-square form on the basis of the division type mode information acquired through a receiver (not shown) , 1010b, 1020a, and 1020b. The second encoding units 1010a, 1010b, 1020a, and 1020b may be independently divided. Accordingly, the image decoding apparatus 100 can determine whether to divide or not divide the image into a plurality of encoding units based on the division type mode information associated with each of the second encoding units 1010a, 1010b, 1020a, and 1020b. According to an embodiment, the image decoding apparatus 100 divides the left second encoding unit 1010a in a non-square form determined by dividing the first encoding unit 1000 in the vertical direction into a horizontal direction, 1012a, and 1012b. In the case where the left second encoding unit 1010a is divided in the horizontal direction, the right-side second encoding unit 1010b is arranged in the horizontal direction in the same manner as the direction in which the left second encoding unit 1010a is divided, As shown in Fig. If the right second encoding unit 1010b is divided in the same direction and the third encoding units 1014a and 1014b are determined, the left second encoding unit 1010a and the right second encoding unit 1010b are arranged in the horizontal direction The third encoding units 1012a, 1012b, 1014a, and 1014b can be determined by being independently divided. However, this is the same result that the image decoding apparatus 100 divides the first encoding unit 1000 into four square-shaped second encoding units 1030a, 1030b, 1030c, and 1030d based on the split mode information, It may be inefficient in terms of image decoding.

According to an embodiment, the image decoding apparatus 100 divides a second encoding unit 1020a or 1020b in a non-square form determined by dividing a first encoding unit 1000 in a horizontal direction into a vertical direction, (1022a, 1022b, 1024a, 1024b). However, when one of the second encoding units (for example, the upper second encoding unit 1020a) is divided in the vertical direction, the image decoding apparatus 100 may be configured to encode the second encoding unit (for example, The encoding unit 1020b) can be restricted such that the upper second encoding unit 1020a can not be divided vertically in the same direction as the divided direction.

FIG. 11 illustrates a process in which the image decoding apparatus 100 divides a square-shaped encoding unit when the split mode information can not be divided into four square-shaped encoding units according to an embodiment.

According to an embodiment, the image decoding apparatus 100 may determine the second encoding units 1110a, 1110b, 1120a, and 1120b by dividing the first encoding unit 1100 based on the division type mode information. The division type mode information may include information on various types in which an encoding unit can be divided, but information on various types may not include information for division into four square units of encoding units. According to the division type mode information, the image decoding apparatus 100 can not divide the first encoding unit 1100 in the square form into the second encoding units 1130a, 1130b, 1130c, and 1130d in the four square form. The image decoding apparatus 100 may determine the non-square second encoding units 1110a, 1110b, 1120a, and 1120b based on the split mode information.

According to an exemplary embodiment, the image decoding apparatus 100 may independently divide the non-square second encoding units 1110a, 1110b, 1120a, and 1120b, respectively. Each of the second encoding units 1110a, 1110b, 1120a, 1120b, etc. may be divided in a predetermined order through a recursive method, which is a method of dividing the first encoding unit 1100 based on the split mode information May be a corresponding partitioning method.

For example, the image decoding apparatus 100 can determine the third encoding units 1112a and 1112b in the form of a square by dividing the left second encoding unit 1110a in the horizontal direction and the right second encoding unit 1110b It is possible to determine the third encoding units 1114a and 1114b in the form of a square by being divided in the horizontal direction. Furthermore, the image decoding apparatus 100 may divide the left second encoding unit 1110a and the right second encoding unit 1110b in the horizontal direction to determine the third encoding units 1116a, 1116b, 1116c, and 1116d in the form of a square have. In this case, the encoding unit can be determined in the same manner as the first encoding unit 1100 is divided into the four second square encoding units 1130a, 1130b, 1130c, and 1130d.

 In another example, the image decoding apparatus 100 can determine the third encoding units 1122a and 1122b in the form of a square by dividing the upper second encoding unit 1120a in the vertical direction, and the lower second encoding units 1120b May be divided in the vertical direction to determine the third encoding units 1124a and 1124b in the form of a square. Further, the image decoding apparatus 100 may divide the upper second encoding unit 1120a and the lower second encoding unit 1120b in the vertical direction to determine the square-shaped third encoding units 1126a, 1126b, 1126a, and 1126b have. In this case, the encoding unit can be determined in the same manner as the first encoding unit 1100 is divided into the four second square encoding units 1130a, 1130b, 1130c, and 1130d.

FIG. 12 illustrates that the processing order among a plurality of coding units may be changed according to a division process of a coding unit according to an exemplary embodiment.

According to an embodiment, the image decoding apparatus 100 may divide the first encoding unit 1200 based on the division type mode information. If the block type is square and the division type mode information indicates that the first encoding unit 1200 is divided into at least one of a horizontal direction and a vertical direction, the image decoding apparatus 100 may generate the first encoding unit 1200 (For example, 1210a, 1210b, 1220a, 1220b, etc.) can be determined by dividing the second coding unit. Referring to FIG. 12, the non-square second encoding units 1210a, 1210b, 1220a, and 1220b, which are determined by dividing the first encoding unit 1200 only in the horizontal direction or the vertical direction, Can be divided independently. For example, the image decoding apparatus 100 divides the second encoding units 1210a and 1210b, which are generated by dividing the first encoding unit 1200 in the vertical direction, in the horizontal direction, and outputs the third encoding units 1216a, 1216b, 1216c and 1216d can be determined and the second encoding units 1220a and 1220b generated by dividing the first encoding unit 1200 in the horizontal direction are divided in the horizontal direction and the third encoding units 1226a, , 1226d. Since the process of dividing the second encoding units 1210a, 1210b, 1220a, and 1220b has been described above with reference to FIG. 11, a detailed description thereof will be omitted.

According to an embodiment, the image decoding apparatus 100 may process an encoding unit in a predetermined order. The features of the processing of the encoding unit in the predetermined order have been described in detail with reference to FIG. 7, and a detailed description thereof will be omitted. 12, the image decoding apparatus 100 divides a first encoding unit 1200 of a square shape into 4 pieces of fourth encoding units 1216a, 1216b, 1216c, 1216d, 1226a, 1226b, 1226c, 1226d Can be determined. According to an embodiment, the image decoding apparatus 100 may process the third encoding units 1216a, 1216b, 1216c, 1216d, 1226a, 1226b, 1226c, and 1226d according to the form in which the first encoding unit 1200 is divided You can decide.

According to an embodiment, the image decoding apparatus 100 divides the generated second encoding units 1210a and 1210b in the vertical direction and divides them in the horizontal direction to determine third encoding units 1216a, 1216b, 1216c, and 1216d And the image decoding apparatus 100 first processes the third encoding units 1216a and 1216c included in the left second encoding unit 1210a in the vertical direction and then processes the third encoding units 1216a and 1216c included in the second right encoding unit 1210b The third encoding units 1216a, 1216b, 1216c, and 1216d can be processed according to the order 1217 of processing the third encoding units 1216b and 1216d in the vertical direction.

According to an embodiment, the image decoding apparatus 100 divides the second encoding units 1220a and 1220b generated in the horizontal direction into vertical directions to determine the third encoding units 1226a, 1226b, 1226c and 1226d And the image decoding apparatus 100 first processes the third encoding units 1226a and 1226b included in the upper second encoding unit 1220a in the horizontal direction and then encodes the third encoding units 1226a and 1226b included in the lower second encoding unit 1220b The third encoding units 1226a, 1226b, 1226c, and 1226d may be processed in accordance with an order 1227 for processing the third encoding units 1226c and 1226d in the horizontal direction.

Referring to FIG. 12, the second encoding units 1210a, 1210b, 1220a, and 1220b are divided to determine the third encoding units 1216a, 1216b, 1216c, 1216d, 1226a, 1226b, 1226c, and 1226d, have. The second encoding units 1210a and 1210b determined to be divided in the vertical direction and the second encoding units 1220a and 1220b determined to be divided in the horizontal direction are divided into different formats, but the third encoding units 1216a , 1216b, 1216c, 1216d, 1226a, 1226b, 1226c, and 1226d, the result is that the first encoding unit 1200 is divided into the same type of encoding units. Accordingly, the image decoding apparatus 100 recursively divides an encoding unit through a different process based on division mode information, thereby eventually determining the same type of encoding units, It can be processed in order.

FIG. 13 illustrates a process of determining the depth of an encoding unit according to a change in type and size of an encoding unit when a plurality of encoding units are determined by recursively dividing an encoding unit according to an embodiment.

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

13, based on block type information (e.g., block type information may indicate '0: SQUARE') indicating a square shape according to an embodiment, the image decoding apparatus 100 may generate a square 1 encoding unit 1300 can be divided to determine the second encoding unit 1302, the third encoding unit 1304, etc. of the lower depth. If the size of the first encoding unit 1300 in the form of a square is 2Nx2N, the second encoding unit 1302 determined by dividing the width and height of the first encoding unit 1300 by 1/2 may have a size of NxN have. Further, the third encoding unit 1304 determined by dividing the width and height of the second encoding unit 1302 by a half size may have a size of N / 2xN / 2. In this case, the width and height of the third encoding unit 1304 correspond to 1/4 of the first encoding unit 1300. If the depth of the first encoding unit 1300 is D, the depth of the second encoding unit 1302, which is half the width and height of the first encoding unit 1300, may be D + 1, The depth of the third encoding unit 1304, which is one fourth of the width and height of the third encoding unit 1300, may be D + 2.

According to an exemplary embodiment, block type information indicating a non-square shape (for example, block type information is' 1: NS_VER 'indicating that the height is a non-square having a width greater than the width or' 2 >), the image decoding apparatus 100 divides the first coding unit 1310 or 1320 in a non-square form into a second coding unit 1312 or 1322 of a lower depth, The third encoding unit 1314 or 1324, or the like.

The image decoding apparatus 100 may determine a second coding unit (for example, 1302, 1312, 1322, etc.) by dividing at least one of the width and the height of the first coding unit 1310 of Nx2N size. That is, the image decoding apparatus 100 can determine the second encoding unit 1302 of NxN size or the second encoding unit 1322 of NxN / 2 size by dividing the first encoding unit 1310 in the horizontal direction, It is also possible to determine the second encoding unit 1312 of N / 2xN size by dividing it in the horizontal direction and the vertical direction.

According to an embodiment, the image decoding apparatus 100 divides at least one of a width and a height of a 2NxN first encoding unit 1320 to determine a second encoding unit (e.g., 1302, 1312, 1322, etc.) It is possible. That is, the image decoding apparatus 100 can determine the second encoding unit 1302 of NxN size or the second encoding unit 1312 of N / 2xN size by dividing the first encoding unit 1320 in the vertical direction, The second encoding unit 1322 of the NxN / 2 size may be determined by dividing the image data in the horizontal direction and the vertical direction.

According to one embodiment, the image decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 1302 of NxN size to determine a third encoding unit (for example, 1304, 1314, 1324, etc.) It is possible. That is, the image decoding apparatus 100 determines the third encoding unit 1304 of N / 2xN / 2 size by dividing the second encoding unit 1302 in the vertical direction and the horizontal direction, or determines the third encoding unit 1304 of N / 4xN / 3 encoding unit 1314 or a third encoding unit 1324 of N / 2xN / 4 size.

The image decoding apparatus 100 may divide at least one of the width and the height of the second encoding unit 1312 of N / 2xN size into a third encoding unit (e.g., 1304, 1314, 1324, etc.) . That is, the image decoding apparatus 100 divides the second encoding unit 1312 in the horizontal direction to generate a third encoding unit 1304 of N / 2xN / 2 or a third encoding unit 1324 of N / 2xN / 4 size ) Or may be divided in the vertical and horizontal directions to determine the third encoding unit 1314 of N / 4xN / 2 size.

According to an exemplary embodiment, the image decoding apparatus 100 divides at least one of the width and the height of the second encoding unit 1322 of NxN / 2 size to generate a third encoding unit 1304, 1314, 1324, . That is, the image decoding apparatus 100 divides the second encoding unit 1322 in the vertical direction to generate a third encoding unit 1304 of N / 2xN / 2 or a third encoding unit 1314 of N / 4xN / 2 size ) Or may be divided in the vertical and horizontal directions to determine the third encoding unit 1324 of N / 2xN / 4 size.

According to an embodiment, the image decoding apparatus 100 may divide a square-shaped encoding unit (for example, 1300, 1302, and 1304) into a horizontal direction or a vertical direction. For example, the first encoding unit 1300 having a size of 2Nx2N is divided in the vertical direction to determine a first encoding unit 1310 having a size of Nx2N or the first encoding unit 1310 having a size of 2NxN to determine a first encoding unit 1320 having a size of 2NxN . According to an exemplary embodiment, when the depth is determined based on the length of the longest side of the encoding unit, the depth of the encoding unit, which is determined by dividing the first encoding unit 1300 of 2Nx2N size in the horizontal direction or the vertical direction, May be the same as the depth of the unit (1300).

According to one embodiment, the width and height of the third encoding unit 1314 or 1324 may correspond to one fourth of the first encoding unit 1310 or 1320. [ When the depth of the first coding unit 1310 or 1320 is D, the depth of the second coding unit 1312 or 1322 which is half the width and height of the first coding unit 1310 or 1320 is D + And the depth of the third encoding unit 1314 or 1324, which is one fourth of the width and height of the first encoding unit 1310 or 1320, may be D + 2.

FIG. 14 illustrates a depth index (hereinafter referred to as a PID) for classifying a depth and a coding unit that can be determined according to the type and size of coding units according to an exemplary embodiment.

According to an embodiment, the image decoding apparatus 100 may divide the first encoding unit 1400 in a square form to determine various types of second encoding units. 14, the image decoding apparatus 100 divides the first encoding unit 1400 into at least one of a vertical direction and a horizontal direction according to the division type mode information, and outputs the second encoding units 1402a, 1402b, and 1404a , 1404b, 1406a, 1406b, 1406c, 1406d. That is, the image decoding apparatus 100 can determine the second encoding units 1402a, 1402b, 1404a, 1404b, 1406a, 1406b, 1406c, and 1406d based on the split mode mode information for the first encoding unit 1400 .

The second encoding units 1402a, 1402b, 1404a, 1404b, 1406a, 1406b, 1406c, and 1406d, which are determined according to the split mode mode information for the first encoded unit 1400 in the form of a square, The depth of field can be determined based on the depth. For example, since the length of one side of the first encoding unit 1400 in the square form is the same as the length of long sides of the second encoding units 1402a, 1402b, 1404a, and 1404b in the non-square form, 1400) and the non-square type second encoding units 1402a, 1402b, 1404a, 1404b are denoted by D in the same manner. On the other hand, when the video decoding apparatus 100 divides the first encoding unit 1400 into four square-shaped second encoding units 1406a, 1406b, 1406c, and 1406d based on the split mode information, Since the length of one side of the second coding units 1406a, 1406b, 1406c and 1406d is half the length of one side of the first coding unit 1400, the length of one side of the second coding units 1406a, 1406b, 1406c and 1406d The depth may be a depth of D + 1 which is one depth lower than D, which is the depth of the first encoding unit 1400.

According to an exemplary embodiment, the image decoding apparatus 100 divides a first encoding unit 1410 having a height greater than a width in a horizontal direction according to division mode information, and generates a plurality of second encoding units 1412a, 1412b, and 1414a , 1414b, and 1414c. According to an embodiment, the image decoding apparatus 100 divides a first encoding unit 1420 of a shape whose width is longer than a height in a vertical direction according to the division mode information to generate a plurality of second encoding units 1422a, 1422b, and 1424a , 1424b, and 1424c.

1412b, 1414a, 1414b, 1414c. 1422a, 1422b, 1424a, 1422b, 1424b, 1424b, 1424b, 1424b, 1424b, 1424c can be determined in depth based on the length of the long side. For example, since the length of one side of the square-shaped second encoding units 1412a and 1412b is 1/2 times the length of one side of the non-square first encoding unit 1410 whose height is longer than the width, The depth of the second encoding units 1412a and 1412b of the form is D + 1 which is one depth lower than the depth D of the first encoding unit 1410 of the non-square form.

Furthermore, the image decoding apparatus 100 may divide the non-square first encoding unit 1410 into odd second encoding units 1414a, 1414b, and 1414c based on the division type mode information. The odd number of second encoding units 1414a, 1414b and 1414c may include non-square second encoding units 1414a and 1414c and a square second encoding unit 1414b. In this case, the length of the long sides of the non-square type second encoding units 1414a and 1414c and the length of one side of the second encoding unit 1414b in the square form are set to 1/10 of the length of one side of the first encoding unit 1410, The depth of the second encoding units 1414a, 1414b, and 1414c may be a depth of D + 1 which is one depth lower than D, which is the depth of the first encoding unit 1410. [ The image decoding apparatus 100 is connected to the first encoding unit 1420 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 1410 The depth of the encoding units can be determined.

According to an exemplary embodiment, the image decoding apparatus 100 determines an index (PID) for distinguishing the divided coding units. If the odd-numbered coding units are not the same size, The index can be determined based on the index. 14, an encoding unit 1414b positioned at the center among the odd-numbered encoding units 1414a, 1414b, and 1414c has the same width as other encoding units 1414a and 1414c, Lt; / RTI > 1414a and 1414c. That is, in this case, the encoding unit 1414b positioned in the middle may include two of the other encoding units 1414a and 1414c. Therefore, if the index (PID) of the coding unit 1414b positioned at the center is 1 according to the scanning order, the coding unit 1414c positioned next to the coding unit 1414c may be three days in which the index is increased by two. That is, there may be a discontinuity in the value of the index. According to an exemplary embodiment, the image decoding apparatus 100 may determine whether odd-numbered encoding units are not the same size based on the presence or absence of an index discontinuity for distinguishing between the divided encoding units.

According to an exemplary embodiment, the image decoding apparatus 100 may determine whether the image is divided into a specific division form based on an index value for distinguishing a plurality of coding units divided from the current coding unit. 14, the image decoding apparatus 100 divides a first coding unit 1410 of a rectangular shape whose height is longer than the width to determine an even number of coding units 1412a and 1412b or an odd number of coding units 1414a and 1414b , And 1414c. The image decoding apparatus 100 may use an index (PID) indicating each coding unit in order to distinguish each of the plurality of coding units. According to one embodiment, the PID may be obtained at a sample of a predetermined position of each coding unit (e.g., the upper left sample).

According to an embodiment, the image decoding apparatus 100 may determine a coding unit of a predetermined position among the coding units determined by using the index for classifying the coding unit. According to an exemplary embodiment, when the division type mode information for the rectangular first type encoding unit 1410 having a height greater than the width is divided into three encoding units, the image decoding apparatus 100 encodes the first encoding unit 1410, Can be divided into three coding units 1414a, 1414b and 1414c. The image decoding apparatus 100 can assign an index to each of the three encoding units 1414a, 1414b, and 1414c. The image decoding apparatus 100 may compare the indexes of the respective encoding units in order to determine the middle encoding unit among the encoding units divided into odd numbers. The image decoding apparatus 100 encodes an encoding unit 1414b having an index corresponding to a middle value among the indices based on the indices of the encoding units by encoding the middle position among the encoding units determined by dividing the first encoding unit 1410 Can be determined as a unit. According to an exemplary embodiment, the image decoding apparatus 100 may determine an index based on a size ratio between coding units when the coding units are not the same size in determining the index for dividing the divided coding units . 14, the coding unit 1414b generated by dividing the first coding unit 1410 is divided into coding units 1414a and 1414c having the same width as the other coding units 1414a and 1414c but different in height Can be double the height. In this case, if the index (PID) of the coding unit 1414b positioned at the center is 1, the coding unit 1414c located next to the coding unit 1414c may be three days in which the index is increased by two. In this case, when the index increases uniformly and the increment increases, the image decoding apparatus 100 may determine that the image decoding apparatus 100 is divided into a plurality of encoding units including encoding units having different sizes from other encoding units. When the division type mode information indicates that the division type mode information is divided into an odd number of encoding units, the image decoding apparatus 100 determines that the encoding unit (for example, the middle encoding unit) at a predetermined position among the odd number of encoding units is different from the encoding units You can split the current encoding unit into a form. In this case, the image decoding apparatus 100 may determine an encoding unit having a different size by using an index (PID) for the encoding unit. However, the index and the size or position of the encoding unit at a predetermined position to be determined are specific for explaining an embodiment, and thus should not be construed to be limited thereto, and various indexes, positions and sizes of encoding units can be used Should be interpreted.

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

FIG. 15 illustrates that a plurality of coding units are determined according to a plurality of predetermined data units included in a picture according to an embodiment.

According to one embodiment, a predetermined data unit may be defined as a unit of data in which an encoding unit begins to be recursively segmented using segmentation mode information. That is, it may correspond to a coding unit of the highest depth used in 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 image decoding apparatus 100 may divide the current picture into a plurality of reference data units. According to an embodiment, the image decoding apparatus 100 may divide a plurality of reference data units for dividing the current picture into pieces using the split mode 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 exemplary embodiment, the image decoding apparatus 100 may determine in advance a minimum size that the reference data unit included in the current picture can have. Accordingly, the image decoding apparatus 100 can determine reference data units of various sizes having a size larger than a minimum size, and can determine at least one encoding unit using the split mode information based on the determined reference data unit .

Referring to FIG. 15, the image decoding apparatus 100 may use a square-shaped reference encoding unit 1500 or a non-square-shaped reference encoding unit 1502. 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 exemplary embodiment, a receiver (not shown) of the video decoding apparatus 100 may acquire at least one of information on the type of the reference encoding unit and information on the size of the reference encoding unit from the bitstream for each of the various data units have. The process of determining at least one encoding unit included in the reference type encoding unit 1500 is described in detail in the process of dividing the current encoding unit 300 of FIG. 3, and the non- Is determined in the process of dividing the current encoding unit 400 or 450 of FIG. 4, so that a detailed description thereof will be omitted.

In order to determine the size and the type of the reference encoding unit according to a predetermined data unit predetermined based on a predetermined condition, the image decoding apparatus 100 may include an index for identifying the size and type of the reference encoding unit Can be used. That is, a receiving unit (not shown) receives 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 image decoding apparatus 100 can determine the size and shape of the reference data unit for each data unit satisfying the predetermined condition by using the index. When the information on the type of the reference encoding unit and the information on the size of the reference encoding unit are obtained from the bitstream for each relatively small data unit and used, the use efficiency of the bitstream may not be good. Therefore, Information on the size of the reference encoding unit and information on the size of the reference encoding unit can be acquired and used. In this case, at least one of the size and the type of the reference encoding unit corresponding to the index indicating the size and type of the reference encoding unit may be predetermined. That is, the image decoding apparatus 100 selects at least one of the size and the type of the reference encoding unit in accordance with the index, thereby obtaining at least one of the size and the type of the reference encoding unit included in the data unit, You can decide.

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

16 shows a processing block serving as a reference for determining a determination order of a reference encoding unit included in a picture 1600 according to an embodiment.

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

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

According to an exemplary embodiment, a receiver (not shown) of the image decoding apparatus 100 may acquire information on the size of a processing block from a 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 receiving unit (not shown) may obtain the information on the size of the processing block from the bitstream for each of the plurality of data units, and the image decoding apparatus 100 divides the picture using the 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 an embodiment, the image decoding apparatus 100 may determine the sizes of the processing blocks 1602 and 1612 included in the picture 1600. For example, the video decoding apparatus 100 can determine the size of the processing block based on information on the size of the processing block obtained from the bitstream. Referring to FIG. 16, the image decoding apparatus 100 according to an exemplary embodiment of the present invention may be configured such that the horizontal size of the processing blocks 1602 and 1612 is four times the horizontal size of the reference encoding unit, four times the vertical size of the reference encoding unit, You can decide. The image decoding apparatus 100 may determine an order in which at least one reference encoding unit is determined in at least one processing block.

According to one embodiment, the video decoding apparatus 100 may determine each processing block 1602, 1612 included in the picture 1600 based on the size of the processing block, and may include in the processing blocks 1602, 1612 The determination order of at least one reference encoding unit is determined. The determination of the reference encoding unit may include determining the size of the reference encoding unit according to an embodiment.

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

According to one embodiment, the image decoding apparatus 100 may obtain information on a determination order of a reference encoding unit from a bitstream for each specific data unit. For example, a receiving unit (not shown) may acquire information on a determination order of a reference encoding unit from a bitstream for each data unit such as an image, a sequence, a picture, a slice, a slice segment, and a processing block. Since the information on the determination order of the reference encoding unit indicates the reference encoding unit determination order in the processing block, the information on the determination order can be obtained for each specific data unit including an integer number of processing blocks.

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

According to one embodiment, the receiving unit (not shown) may obtain information on the reference encoding unit determination order from the bitstream as information related to the processing blocks 1602 and 1612, 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 reference frames 1602 and 1612 and determine at least one reference encoding unit included in the picture 1600 according to the determination order of the encoding units. Referring to FIG. 16, the image decoding apparatus 100 may determine a determination order 1604 and 1614 of at least one reference encoding unit associated with each of the processing blocks 1602 and 1612. For example, when information on the order of determination of the reference encoding unit is obtained for each processing block, the reference encoding unit determination order associated with each processing block 1602, 1612 may be different for each processing block. If the reference encoding unit determination order 1604 related to the processing block 1602 is a raster scan order, the reference encoding unit included in the processing block 1602 can be determined according to the raster scan order. On the other hand, when the reference encoding unit determination order 1614 related to the other processing block 1612 is a reverse order of the raster scan order, the reference encoding unit included in the processing block 1612 can be determined according to the reverse order of the raster scan order.

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

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

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

The image decoding apparatus 100 can determine the division rule of the image. The division rule may be predetermined between the video decoding apparatus 100 and the video encoding apparatus 150. [ The image decoding apparatus 100 can determine the division rule of the image based on the information obtained from the bit stream. The video decoding apparatus 100 includes a sequence parameter set, a picture parameter set, a video parameter set, a slice header, and a slice segment header The partitioning rule can be determined based on the information obtained from at least one. The video decoding apparatus 100 may determine the division rule differently according to a frame, a slice, a temporal layer, a maximum encoding unit, or an encoding unit.

The image decoding apparatus 100 can determine the division rule based on the block type of the encoding unit. The block shape may include the size, shape, width and height ratio, direction of the encoding unit. The image encoding apparatus 150 and the image decoding apparatus 100 may determine in advance that the division rule is determined based on the block type of the encoding unit. However, the present invention is not limited thereto. The image decoding apparatus 100 can determine the segmentation rule based on the information obtained from the bit stream received from the image encoding apparatus 150. [

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

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

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

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

Determination of the division rule based on the size of the encoding unit may be a predetermined division rule between the image encoding device 150 and the image decoding device 100. [ Further, the video decoding apparatus 100 can determine the division rule based on the information obtained from the bit stream.

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

In addition, the image decoding apparatus 100 can determine the division rule so that the encoding units generated by different division paths do not have the same block form. However, the present invention is not limited thereto, and coding units generated by different division paths may have the same block form. The coding units generated by different division paths may have different decoding processing orders. Since the decoding procedure has been described with reference to FIG. 12, a detailed description thereof will be omitted.

17 to 18, a filter used for the current sample is determined based on at least one of the distance between the current sample and the reference sample in the current block and the size of the current block, and intra prediction is performed based on the determined filter Decoding method and apparatus will be described in detail.

17 is a view for explaining intra prediction modes according to an embodiment.

Referring to FIG. 17, intra prediction modes according to an embodiment may include a planar mode (mode 0) and a DC mode (mode 1). In addition, the intra prediction modes may include an angular mode (the second to sixth modes) having a prediction direction. The angular mode may include a diagonal mode (No. 2 mode or No. 66 mode), a horizontal mode (No. 18 mode), and a vertical mode (No. 50 mode).

Although the intra-prediction modes according to the embodiment have been described with reference to FIG. 17, the present invention is not limited thereto, and various intra prediction modes can be provided by adding a new intra-prediction mode or replacing an existing intra- , It is easily understood by those skilled in the art that the mode number of each intra prediction mode may vary depending on the case.

18 illustrates a method of generating a prediction sample of a current sample using another filter based on at least one of a distance between a current sample and a reference sample and a size of a current block, according to one embodiment of the present disclosure Fig.

18, the image decoding apparatus 100 generates a prediction sample value for samples in the current block 1800 using the reference samples 1820 to perform intra prediction on the current block 1800 can do.

For example, the image decoding apparatus 100 may extract a current block 1800 from a current sample 1810 using a reference sample that intersects with an extension line 1830 of a prediction direction of an intra-prediction mode of the current block 1800, ( _{X, y} ) of the current sample 1810 of the current sample ( _{x, y} ) in accordance with Equation (1). Here, x and y may refer to the x-coordinate and the y-coordinate of the current sample based on the position of the upper left sample of the current block.

At this time, f _{k, i} is M + 1 (M is an integer) filters filter set (filter set) in k + 1 i + 1-th (0 <= i <= 3 ) filter coefficients for the second filter comprising the . &Lt; / RTI &gt; a ₀ is Refers to the sample value of the reference sample that intersects the extension line 1830 from the current sample 1810 and a _-1 is the reference value that is located immediately to the left of the reference sample that intersects the extension line 1830 from the current sample 1810 A ₁ denotes a sample value of a reference sample located immediately to the right of a reference sample that intersects an extension line 1830 from the current sample 1810, a ₂ denotes a sample value of the current sample 1810, May refer to the sample value of the reference sample located second to the right from the reference sample that intersects the extension line 1830 from the reference sample.

Above, the reference sample value according to equation (1) a _0, a _{-1, 1} a, but using a ₂ describes the information to generate a predicted sample value of the current sample, but not limited to, on the basis of a ₀ Those skilled in the art will appreciate that the sample values of the various reference samples in the vicinity can be used to generate a predicted value of the current sample. For example, a _-2 , a _-1 , a ₀ , a ₁ may be used to generate the predicted sample value of the current sample. Alternatively, a ₀ , a ₁ , a ₂ , a ₃ may be used to generate the predicted sample value of the current sample.

The image decoding apparatus 100 uses the current sample 1810 among a plurality of filters f _k (0 <= k <= M) based on the distance between the current sample 1810 and the reference sample and the size of the current block 1800 The filter to be determined can be. For example, the image decoding apparatus 100 previously determines the range of samples in which each of the plurality of filters f _k (0 <= k <= M) is used by multiplying the current block size by a predetermined ratio, The filter used in the range of samples including the sample 1810 may be determined as the filter used in the current sample 1810. [ For example, the number of filters included in the filter set may be four. That is, the filter set may include a filter _{f 0, f 1, f 2} , f 3.

The image decoding apparatus 100 determines whether the distance between the current sample 1810 and the reference sample located on the upper side of the current sample 1810 is [0, size / 4] or the distance between the current sample 1810 and the reference sample located on the left side of the current sample 1810 F ₀ can be determined as the filter used in the current sample 1810 if the distance between the reference samples located in the current sample 1810 is [0, size / 4). In this case, the size may be the size (height or width) of the current block 1800. The image decoding apparatus 100 determines that the distance between the current sample 1810 and the reference sample located on the upper side of the current sample 1810 is [size / 4, size / 2], and the current sample 1810 and the current sample 1810, The distance between the reference samples located on the left side of the current sample 1810 is [size / 4, size], or the distance between the current sample 1810 and the sample located on the left side of the current sample 1810 is [ If the distance between the current sample 1810 and the sample located on the upper side of the current sample 1810 is [size / 4, size), f ₁ can be determined as the filter used in the current sample 1810. The image decoding apparatus 100 determines that the distance between the current sample 1810 and the reference sample located on the upper side of the current sample 1810 is [size / 2, 3 * size / 4] 1810 is [size / 2, size], or the distance between the current sample 1810 and the sample located on the left side of the current sample 1810 is [size / 2, 3 * size / 4), and if the distance between the current sample 1810 and the sample located above the current sample 1810 is [size / 2, size), then f ₂ can be determined as the filter used for the current sample 1810 .

The image decoding apparatus 100 determines that the distance between the current sample 1810 and the reference sample located above the current sample 1810 is [3 * size / 4, size], and the current sample 1810 and the current sample 1810, 4, size), and the distance between the current sample 1810 and the sample located on the upper side of the current sample 1810 is [3 * size / 4, size] , Then f ₃ can be determined as the filter used in the current sample 1810.

18, when the current sample 1810 is located in the first region 1850, the image decoding apparatus 100 may determine f ₀ as a filter used in the current sample 1810. The image decoding apparatus 100 may determine f ₁ as a filter used in the current sample 1810 when the current sample 1810 is located in the second region 1860. When the current sample 1810 is located in the third region 1870, the image decoding apparatus 100 calculates f ₂ In the current sample 1810 Can be determined by the filter used. The image decoding apparatus 100 may determine f ₄ as a filter used in the current sample 1810 when the current sample 1810 is located in the fourth region 1880.

At this time, the smoothing strengths of the filters f ₀ , f ₁ , f ₂ , and f ₃ are set so that the filter f ₀ used for the sample whose distance from the reference sample is the closest is used and the filter f ₃ Can be the largest.

18, the description has been given of the case where the video decoding apparatus 100 performs intra prediction on the current block using the four filters for the current block 1800. However, the present invention is not limited to this, It will be appreciated by those skilled in the art that the apparatus 100 may perform intra prediction on a current block using a varying number of filters. At this time, based on the number of filters, the range of samples in which each filter is used can be variously determined. 18, when the number of filters used for the current block 1800 is determined to be three, the image decoding apparatus 100 integrates the third region 1870 and the fourth region 1880, If the current sample 1810 is located in the third region 1870 or the fourth region 1880, then f ₃ can be determined as the filter used for the current sample 1810.

Alternatively, the image decoding apparatus 100 can previously determine the range of samples in which each of the plurality of filters f _k (0 <= k <= M) is used based on the distance between the sample in the current block and the reference sample, The filter used in the range of the included samples can be determined by the filter used in the current sample.

For example, if the minimum distance between the current vertical distance and the horizontal distance between the current sample and the reference sample is smaller than 4, the image decoding apparatus 100 can determine f ₀ as a filter used in the current sample. The image decoding apparatus 100 may determine f ₁ as a filter used in the current sample if the minimum distance between the current vertical distance and the horizontal distance between the current sample and the reference sample is greater than or equal to 4 and less than 8. If the minimum distance of the vertical and horizontal distances between the current sample and the reference sample is greater than or equal to 8 and less than 16, the image decoding apparatus 100 may determine f ₂ as a filter used in the current sample. If the minimum distance of the vertical and horizontal distances between the current sample and the reference sample is greater than or equal to 16 and smaller than 32, the image decoding apparatus 100 may determine f ₃ as a filter used in the current sample. The image decoding device 100 may determine the current sample and the reference sample, if the minimum distance of the vertical and horizontal distance greater than or equal to 32 less than 64 between the filter to be used for f ₄ to the current sample. The image decoding apparatus 100 can determine f ₅ as the filter used in the current sample when the minimum distance between the vertical and horizontal distances between the current sample and the reference sample is larger than 64. [ In this case, the number of filters used in the current block may be changed according to the size of the current block in the video decoding apparatus 100. The image decoding apparatus 100 that can pre-determine the current sample and the reference vertical distance and a horizontal distance in the plurality of filters based on a minimum distance of between samples _{f k (0 <= k <} = M) range of samples each of which is used The distance between the reference sample that intersects the extension of the prediction direction from the current sample and the reference sample is determined based on the intra prediction mode of the current block, and a plurality of filters f _k (0 < = k < = M), respectively, can determine in advance the range of samples to be used.

Also, the image decoding apparatus 100 may multiply the size of the current block by a predetermined ratio to determine in advance a range of samples in which each of the plurality of filters f _k (0 <= k <= M) is used, The present invention is not limited to this, and the size of the current block and the size of the current block may be determined based on the distance between the reference sample and each of the plurality of filters f _k (0 <= k <= M) It will be appreciated by those skilled in the art that a range of samples can be determined for each of a plurality of filters based on various methods based on at least one of the distance between the sample and the reference sample.

Also, the image decoding apparatus 100 can determine the number of filters used in the current block based on the size (height or width) of the current block, and determine a filter corresponding to the number of filters. For example, when the size of the current block is equal to or greater than a predetermined size, the image decoding apparatus 100 divides the filters f0 _, f1 _, f2 _{, ...,} fM _-1 into a filter . If the current block size is smaller than the predetermined size, the image decoding apparatus 100 can determine the number of filters used in the current block to be a predetermined number K (K is an integer) smaller than M. In this case, the image decoding apparatus 100 can determine a predetermined number of K filters by a predetermined combination among various combinations possible for the filters f _0, f _1, f _{2, ...,} f _M-1 . For example, the image decoding apparatus 100 may determine the filters f0 _, f1 _, f2 _{, ...,} fK _-1 as the filters used in the current block. For example, if the image decoding apparatus 100 determines that the number of filters used in the current block is two, the filters f _{0 and} f ₁ can be determined as filters used in the current block. Alternatively, when the number of filters used in the current block is determined to be two, the image decoding apparatus 100 may determine the filters f _{0 and} f _M-1 as filters used in the current block.

For example, the image decoding device 100 may determine as to the 4-tap filter set comprising a filter f _0, f _1, f ₂ and f ₃ are used for the intra prediction of the current block. For example, the image decoding apparatus 100 may determine the coefficient of the filter f ₀ to be {-2,126, 4,0}. (The coefficients of the filter may be a filter of a filter applied to a fractional pixel postion. Coefficient), the image decoding apparatus 100 can determine the coefficient of the filter f ₁ to be {12, 99, 18, -1}. The image decoding apparatus 100 can determine the coefficients of the filter f ₂ as {21, 82, 23, 2}. The image decoding apparatus 100 can determine the coefficients of the filter f ₃ as {31, 63, 33, 1}. At this time, the filter f ₀ is a filter f _0, f _1, f _2, f ₃ may be in the smoothing intensity is weakest filter wherein the filter f ₃ has a filter f _0, f _1, f _2, f ₃ the smoothing intensity most of the It can be a strong filter. On the other hand, it is understood by those skilled in the art that the values of the coefficients of the filter can be changed slightly (e.g., +1 to 5, -1 to 5) without being limited to the values of the coefficients listed above.

On the other hand, the image decoding apparatus 100 can determine the number of reference samples used to determine the predicted sample value of the current sample based on the distance between the current sample and the reference sample. The image decoding apparatus 100 may perform filtering on the current sample using reference samples corresponding to the number of reference samples.

For example, when the distance between the current sample and the reference sample is greater than or equal to a predetermined distance, the image decoding apparatus 100 performs filtering on the current sample using M reference samples, Can be generated. If the distance between the current sample and the reference sample is smaller than the predetermined distance, the image decoding apparatus 100 generates a predicted sample value of the current sample by performing filtering on the current sample using a reference sample smaller than M . For example, if the distance between the current sample and the reference sample is less than a predetermined distance, the image decoding apparatus 100 may generate the predicted sample value of the current sample by performing filtering using one or two reference samples have. The image decoding apparatus 100 may generate the predicted sample value of the current sample by performing filtering using four or more reference samples if the distance between the current sample and the reference sample is greater than or equal to a predetermined distance.

The image decoding apparatus 100 can determine the number of reference samples used for filtering the current sample by adjusting the number of taps of the filter. For example, when the distance between the current sample and the reference sample is greater than or equal to a predetermined distance, the image decoding apparatus 100 may determine a filter having four or more taps as a filter used in the current sample. If the distance between the current sample and the reference sample is smaller than the predetermined distance, the image decoding apparatus 100 may determine the one-tap filter or the two-tap filter to be the filter used in the current sample. At this time, the image decoding apparatus 100 may not perform the filtering instead of performing the filtering using the one-tap filter.

Alternatively, the image decoding apparatus 100 may determine the number of reference samples used for filtering the current sample by fixing the number of taps of the filter and adjusting the value of some filter coefficient.

For example, when the distance between the current sample and the reference sample is smaller than a predetermined distance, the image decoding apparatus 100 determines coefficients of the filter used for the current sample to be {0,128,0, 0}. &Lt; / RTI &gt; If the distance between the current sample and the reference sample is greater than or equal to a predetermined distance, the image decoding apparatus 100 may determine the coefficient of the filter used for the current sample to be {32, 63, 31, 1}.

The video decoding apparatus 100 may determine a filter to be used for a current sample among the filters used in the current block based on the position of the current sample in the current block, the intra prediction mode, and the size of the current block.

For example, the image decoding apparatus 100 determines to use the first filter when the x-axis coordinate value of the current sample is smaller than a predetermined value or when the y-axis coordinate value of the current sample is smaller than a predetermined value, If not, it can be determined to use the second filter.

At this time, the first filter has a smoothing strength smaller than that of the second filter and can have a sharp characteristic. At this time, the predetermined value may be eight. But is not limited thereto and may be one of various values of a multiple of four.

When the index value of the intra prediction mode of the current block is smaller than or equal to the index value (DIA_IDX) of the 34th mode, the image decoding apparatus 100 determines that the width of the current block is smaller than or equal to the first value, And may be less than or equal to the second value. At this time, the first value may be smaller than the second value. For example, the first value may be 16, and the second value may be 32. [

When the index value of the intra prediction mode of the current block is larger than the index value (DIA_IDX) of the 34th mode, the image decoding apparatus 100 determines whether the width of the current block is less than or equal to the first value, Value is less than or equal to the value. At this time, the first value may be larger than the second value. The first value may be 32, and the second value may be 16.

The image decoding apparatus 100 can determine a filter to be used in the current block based on the width and the height of the current block. For example, the image decoding device 100 is present, the width of the blocks equal to or less than the first value, when the height of the current block is less than or equal to the second value, a filter to be used _f0, f ₁ in the current block You can decide. If the width of the current block is larger than the first value or the width of the current block is larger than the second value, the image decoding apparatus 100 may determine f ₂ and f ₃ as the filter used in the current block.

FIG. 19 is a diagram illustrating an example of a case where a negative (double) convolution order between coding units is determined in a forward or backward direction on the basis of an encoding order flag according to an embodiment of the present disclosure, Lt; / RTI &gt; can be used for intra prediction.

Referring to FIG. 19, the maximum encoding unit 2950 is divided into a plurality of encoding units 1956, 1958, 1960, 1962, 1968, 1970, 1972, 1974, 1980, 1982, 1984, The maximum encoding unit 1950 corresponds to the top node 1900 of the tree structure. And a plurality of encoding units 1956, 1958, 1960, 1962, 1968, 1970, 1972, 1974, 1980, 1982, 1984, 1922, 1924, 1930, 1932, 1934, 1936). Upper coding order flags 1902, 1914 and 1926 correspond to arrows 1952, 1964 and 1976 and upper coding order flags 1904 and 1916 and 1928 correspond to arrows 1954, ).

The upper coding order flag indicates the coding order of two coding units located at the uppermost of four coding units of the same depth. If the upper coding order flag is 0, the coding is performed in the forward direction. Conversely, when the upper encoding order flag is 1, the encoding is performed in the reverse direction.

Similarly, the lower coding order flag indicates the coding order of two coding units located at the lower one of the four equal-depth coding units. If the lower coding order flag is 0, coding is performed in the forward direction. Conversely, when the lower coding order flag is 1, the coding is performed in the reverse direction.

For example, since the upper coding order flag 1914 is 0, the coding order between the coding units 1968 and 1970 is determined from the left to the right direction. Since the lower coding order flag 1916 is 1, the coding order between the coding units 1972 and 1974 is determined from the right side to the left side in the reverse direction.

According to the embodiment, the upper coding order flag and the lower coding order flag may be set to have the same value. For example, when the upper coding order flag 1902 is determined to be 1, the lower coding order flag 1904 corresponding to the upper coding order flag 1902 may also be determined as 1. [ The value of the upper order coding order flag and the value of the lower order coding order flag are determined by 1 bit, so that the information amount of the coding order information decreases.

According to an embodiment, the upper coding order flag and the lower coding order flag of the current coding unit can be determined with reference to at least one of an upper coding order flag and a lower coding order flag applied to a coding unit having a lower depth than the current coding unit. For example, the upper coding order flag 1926 and the lower coding order flag 1928 applied to the coding units 1980, 1982, 1984, 1986 include a lower coding order flag 1916 applied to the coding units 1972 and 1974, . &Lt; / RTI &gt; Therefore, the upper coding order flag 1926 and the lower coding order flag 1928 can be determined to have the same value as the coding order flag 1916. [ The values of the upper coding order flag and the lower coding order flag are determined from the upper coding unit of the current coding unit, so that the coding order information is not obtained from the bit stream. Therefore, the information amount of the coding order information decreases.

At this time, the video decoding apparatus 100 decodes the data of the samples included in the right adjacent coded unit 1958 decoded before the current coding unit 1986 and the data of the samples included in the upper adjacent coding units 1980 and 1982 The data of the samples (right reference line) included in the right adjacent encoding unit 1958 and the data of the samples (upper reference line) included in the upper adjacent encoding units 1980 and 1982 are used It is possible to perform the prediction according to the embodiment of the present disclosure.

That is, referring to Figs. 17 to 18, a filter used for a current sample is determined based on at least one of the size of a current block and a distance between a current sample and a reference sample, and adaptive intra prediction is performed based on the determined filter And intra prediction is performed on the basis of reference samples adjacent to the upper or left corner of the current block on the premise that subdecryption is performed according to a subdecryption sequence for a conventional coding unit However, the present invention is not limited to this. As shown in FIG. 19, when the order of partial coding / decoding between adjacent coding units is the order of the right coding unit and the left coding unit, Those skilled in the art can easily understand that intra prediction can be performed based on the intra prediction.

According to various embodiments of the present disclosure, the prediction accuracy can be improved by adaptively determining the filter used for the current sample based on the distance between the current sample and the reference sample, and a prediction block of a natural pattern can be generated.

That is, smoothing intensity is small for a sample whose distance is close to that of the reference sample, and prediction accuracy can be improved by using a filter having a sharp characteristic. In addition, a prediction block of a natural pattern can be generated by using a filter of which the smoothing intensity is high for a sample which is far from the reference sample.

In addition, by generating a prediction block having a natural pattern and a high prediction accuracy, it is possible to correct a sudden prediction error, thereby improving the efficiency of the tranform.

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 embodied 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, DVD, etc.).

Claims (15)

Obtaining information on a transform coefficient of a current block from a bitstream; Determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block; Obtaining a prediction block of a current block including prediction samples of the current sample generated using the determined filter; Acquiring a residual block of the current block based on information on a transform coefficient of the obtained current block; And And reconstructing the current block based on the prediction block of the current block and the residual block of the current block. The method according to claim 1, Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Determining a type of a filter used in the current sample and a coefficient of the filter based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block; / RTI &gt; 3. The method of claim 2, The type of the filter may be a low pass filter, a Gaussian filter, a bilateral filter, a uniform filter, a bilinear interpolation filter, a cubic filter a cubic filter, and a DCT (Discrete Cosine Transform) filter. The method according to claim 1, Wherein the number of taps of the filter used in the current sample is a predetermined value or is determined based on at least one of a distance between the current sample and the reference sample and a size of the current block. The method according to claim 1, Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Determining a plurality of filters for the current block based on at least one of a size of the current block and a distance between a sample in the current block and a reference sample; And And determining a filter corresponding to the current sample among the plurality of filters for the current block. 6. The method of claim 5, Wherein the step of determining a plurality of filters for the current block based on at least one of a size of the current block and a distance between a sample in the current block and a reference sample, Determining a plurality of filters for the current block based on a ratio of a height or a width of the current block to a distance between a sample in the current block and a reference sample. The method according to claim 1, Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Determining a first reference sample corresponding to a sample in the current block based on an intra prediction mode of the current block; Determining a plurality of filters for the current block based on a distance between the sample and a first reference sample; And And determining a filter corresponding to the current sample among the plurality of filters for the current block. The method according to claim 1, Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Determining a number of filters used in the current block based on the size of the current block and determining a filter for the current block corresponding to the number of the filters; And Determining a filter to be used for the current sample among the filters for the current block based on at least one of the distance between the current sample and the reference sample and the size of the current block. The method according to claim 1, Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Determining a filter used for the current sample based on at least one of an intra prediction mode of the current block and a shape of the current block. The method according to claim 1, Determining a filter to be used for the current sample based further on at least one of an intra prediction mode of the current block and a shape of the current block, Determining a filter to be used for the current sample based on at least one of a distance between a current sample and a reference sample in the current block and a size of the current block if the intra prediction mode of the current block is a predetermined intra prediction mode And decoding the decoded image. The method according to claim 1, Wherein determining a filter to be used for the current sample based further on at least one of an intra prediction mode of the current block and a shape of the current block, If the width of the current block is less than or equal to a predetermined first value and the height of the current block is less than or equal to a predetermined second value, a distance between a current sample and a reference sample in the current block, And determining a filter to be used for the current sample based on at least one of the first and second samples. The method according to claim 1, Wherein determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Determining a first filter for the current sample if the distance between the current sample and the reference sample is less than a predetermined value and if the distance between the current sample and the reference sample is greater than a predetermined value, 2 &lt; / RTI &gt; filter, Wherein the smoothing strength of the first filter is smaller than the smoothing strength of the second filter. 5. The method of claim 4, Wherein the predetermined value is an integer of 4 or more. Determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block; Generating a prediction block of a current block including prediction samples of the current sample generated using the determined filter; And And encoding the information on the transform coefficient of the current block based on the prediction block of the current block. Obtains information on a transform coefficient of the current block from the bitstream, Determining a filter to be used for the current sample based on at least one of a distance between a current sample in the current block and a reference sample and a size of the current block, Acquiring a prediction block of a current block including prediction samples of the current sample generated using the determined filter, A processor for obtaining a residual block of the current block based on the obtained information about the transform coefficient of the current block and restoring the current block based on the prediction block of the current block and the residual block of the current block And decodes the video signal.

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