KR20180103733A - Method and apparatus for image encoding or image decoding - Google Patents

Abstract

A method for decoding an image according to the present invention is a method for decoding an image according to each coding unit corresponding to a unit to which inter prediction or intra prediction is applied. The method for decoding an image includes the steps of inducing a prediction unit of a first coding unit using motion information; and inducing a prediction unit of a second coding unit using motion information induced based on the motion information of the first coding unit. Accordingly, the present invention can efficiently perform the inter prediction on a block to be encoded or decoded.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for encoding or decoding an image,

The present invention relates to a method and apparatus for image coding or decoding.

Recently, the demand for high resolution and high quality images such as high definition (HD) image and ultra high definition (UHD) image is increasing in various applications. As the image data has high resolution and high quality, the amount of data increases relative to the existing image data. Therefore, when the image data is transmitted using a medium such as a wired / wireless broadband line or stored using an existing storage medium, The storage cost is increased. High-efficiency image compression techniques can be utilized to solve such problems as image data becomes high-resolution and high-quality.

An inter picture prediction technique for predicting a pixel value included in a current picture from a previous or a subsequent picture of a current picture by an image compression technique, an intra picture prediction technique for predicting a pixel value included in a current picture using pixel information in the current picture, There are various techniques such as an entropy encoding technique in which a short code is assigned to a value having a high appearance frequency and a long code is assigned to a value having a low appearance frequency. Image data can be effectively compressed and transmitted or stored using such an image compression technique.

On the other hand, demand for high-resolution images is increasing, and demand for stereoscopic image content as a new image service is also increasing. Video compression techniques are being discussed to effectively provide high resolution and ultra-high resolution stereoscopic content.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for efficiently performing inter-prediction on a block to be coded or decoded when a video signal is encoded or decoded.

An object of the present invention is to provide a method and apparatus for image encoding / decoding using a motion-shared coding unit.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

The image decoding method according to the present invention is an image decoding method for decoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied, the method comprising: deriving a prediction unit of a first coding unit using motion information ; And deriving a prediction unit of the second coding unit using the motion information derived based on the motion information of the first coding unit.

Further, the image decoding method according to the present invention may further comprise determining whether the first coding unit and the second coding unit belong to the same motion shared coding unit, and the first coding unit and the second coding unit If the coding unit belongs to the same motion-shared coding unit, the prediction unit of the second coding unit can be derived using the motion information derived based on the motion information of the first coding unit.

Also, when at least one of the first coding unit or the second coding is a non-regular coding unit, the motion sharing coding unit may be a square block including the at least one non-regular coding unit have.

In addition, the size of the motion-shared coding unit may be determined based on a syntax element representing the size of the motion-shared coding unit extracted from the bitstream.

In addition, the first coding unit and the second coding unit may share the same motion information, according to a syntax element indicating whether coding units in the motion-shared coding unit share motion information.

The shared motion information may include at least one of a prediction direction information, a spatial motion vector, a temporal motion vector, a motion vector candidate list, a motion vector indicator, a merge index, a merge candidate list, a reference picture index or a reference picture list .

The image coding method according to the present invention is an image coding method for coding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied, the method comprising: a first coding unit for performing motion estimation and motion compensation ; Performing motion estimation and motion compensation on the second coding unit using inter prediction; And encoding the shared motion information if the first coding unit and the second coding unit share the same motion information.

An image decoding apparatus according to the present invention is an image decoding apparatus for decoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied. The image decoding apparatus derives a prediction unit of the first coding unit using motion information And derives a prediction unit of the second coding unit using the motion information derived based on the motion information of the first coding unit.

The image encoding apparatus according to the present invention is an image encoding apparatus for encoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied, An inter-prediction unit for deriving a prediction unit of the second coding unit using inter prediction; And an entropy coding unit for coding the shared motion information when the first coding unit and the second coding unit share the same motion information.

A recording medium according to the present invention is a recording medium including a video signal bitstream, wherein a video signal bitstream included in the recording medium is encoded by a coding unit corresponding to a unit to which inter prediction or intra prediction is applied The image encoding method comprising the steps of: deriving a prediction unit of a first coding unit using inter prediction; deriving a prediction unit of a second coding unit using inter prediction; ; And encoding the shared motion information if the first coding unit and the second coding unit share the same motion information.

The features briefly summarized above for the present invention are only illustrative aspects of the detailed description of the invention which are described below and do not limit the scope of the invention.

According to the present invention, inter prediction can be efficiently performed on a block to be coded or decoded.

According to the present invention, encoding and decoding efficiency can be improved by sharing motion information with different coding units.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a block diagram illustrating an image encoding apparatus according to an embodiment of the present invention.
2 is a block diagram illustrating an image decoding apparatus according to an embodiment of the present invention.
FIG. 3 illustrates an example in which a coding block is hierarchically divided based on a tree structure according to an embodiment to which the present invention is applied.
FIG. 4 is a diagram illustrating a partition type in which binary tree-based partitioning is permitted according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating an example in which only a specific type of binary tree-based partitioning is permitted according to an embodiment of the present invention.
FIG. 6 is a diagram for explaining an example in which information related to the allowable number of binary tree division is encoded / decoded according to an embodiment to which the present invention is applied.
7 is a diagram illustrating a partition mode that can be applied to a coding block according to an embodiment of the present invention.
8 is a flowchart illustrating an inter prediction method according to an embodiment of the present invention.
9 is a diagram illustrating a process of deriving motion information of a current block when a merge mode is applied to the current block.
10 is a diagram illustrating a process of deriving motion information of a current block when the AMVP mode is applied to the current block.
11 is a diagram showing an example of a coding tree unit including a non-regular coding unit according to an embodiment to which the present invention is applied.
12 is a diagram illustrating a case where a predetermined size region is set as a motion-shared coding unit according to an embodiment of the present invention.
13 is a diagram showing a syntax element isUseMSCUflag associated with each MSCU according to an embodiment of the present invention.
FIG. 14 is a flowchart illustrating an image encoding method using an MSCU according to an embodiment of the present invention. Referring to FIG.
15 is a flowchart illustrating an image decoding method using an MSCU according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the same reference numerals will be used for the same constituent elements in the drawings, and redundant explanations for the same constituent elements will be omitted.

1 is a block diagram illustrating an image encoding apparatus according to an embodiment of the present invention.

1, the image encoding apparatus 100 includes a picture division unit 110, prediction units 120 and 125, a transform unit 130, a quantization unit 135, a reordering unit 160, an entropy encoding unit An inverse quantization unit 140, an inverse transform unit 145, a filter unit 150, and a memory 155. [

Each of the components shown in FIG. 1 is shown independently to represent different characteristic functions in the image encoding apparatus, and does not mean that each component is composed of separate hardware or one software configuration unit. That is, each constituent unit is included in each constituent unit for convenience of explanation, and at least two constituent units of the constituent units may be combined to form one constituent unit, or one constituent unit may be divided into a plurality of constituent units to perform a function. The integrated embodiments and separate embodiments of the components are also included within the scope of the present invention, unless they depart from the essence of the present invention.

In addition, some of the components are not essential components to perform essential functions in the present invention, but may be optional components only to improve performance. The present invention can be implemented only with components essential for realizing the essence of the present invention, except for the components used for the performance improvement, and can be implemented by only including the essential components except the optional components used for performance improvement Are also included in the scope of the present invention.

The picture division unit 110 may divide the input picture into at least one processing unit. At this time, the processing unit may be a prediction unit (PU), a transform unit (TU), or a coding unit (CU). The picture division unit 110 divides one picture into a plurality of coding units, a prediction unit, and a combination of conversion units, and generates a coding unit, a prediction unit, and a conversion unit combination So that the picture can be encoded.

For example, one picture may be divided into a plurality of coding units. In order to divide a coding unit in a picture, a recursive tree structure such as a quad tree structure can be used. In a coding or decoding scheme in which one picture or a largest coding unit is used as a root and divided into other coding units A unit can be divided with as many child nodes as the number of divided coding units. Under certain constraints, an encoding unit that is no longer segmented becomes a leaf node. That is, when it is assumed that only one square division is possible for one coding unit, one coding unit can be divided into a maximum of four different coding units.

Hereinafter, in the embodiment of the present invention, a coding unit may be used as a unit for performing coding, or may be used as a unit for performing decoding.

The prediction unit may be one divided into at least one square or rectangular shape having the same size in one coding unit, and one of the prediction units in one coding unit may be divided into another prediction Or may have a shape and / or size different from the unit.

If a prediction unit performing intra prediction on the basis of an encoding unit is not the minimum encoding unit at the time of generation, intraprediction can be performed without dividing the prediction unit into a plurality of prediction units NxN.

The prediction units 120 and 125 may include an inter prediction unit 120 for performing inter prediction and an intra prediction unit 125 for performing intra prediction. It is possible to determine whether to use inter prediction or intra prediction for a prediction unit and to determine concrete information (e.g., intra prediction mode, motion vector, reference picture, etc.) according to each prediction method. At this time, the processing unit in which the prediction is performed may be different from the processing unit in which the prediction method and the concrete contents are determined. For example, the method of prediction, the prediction mode and the like are determined as a prediction unit, and the execution of the prediction may be performed in a conversion unit. The residual value (residual block) between the generated prediction block and the original block can be input to the conversion unit 130. [ In addition, the prediction mode information, motion vector information, and the like used for prediction can be encoded by the entropy encoding unit 165 together with the residual value and transmitted to the decoder. When a particular encoding mode is used, it is also possible to directly encode the original block and transmit it to the decoding unit without generating a prediction block through the prediction units 120 and 125.

The inter-prediction unit 120 may predict a prediction unit based on information of at least one of a previous picture or a following picture of the current picture, and may predict a prediction unit based on information of a partially- Unit may be predicted. The inter prediction unit 120 may include a reference picture interpolation unit, a motion prediction unit, and a motion compensation unit.

In the reference picture interpolating section, the reference picture information is supplied from the memory 155 and pixel information of an integer pixel or less can be generated in the reference picture. In the case of a luminance pixel, a DCT-based interpolation filter having a different filter coefficient may be used to generate pixel information of an integer number of pixels or less in units of quarter pixels. In the case of a color difference signal, a DCT-based 4-tap interpolation filter having a different filter coefficient may be used to generate pixel information of an integer number of pixels or less in units of 1/8 pixel.

The motion prediction unit may perform motion prediction based on the reference picture interpolated by the reference picture interpolating unit. Various methods such as Full Search-based Block Matching Algorithm (FBMA), Three Step Search (TSS), and New Three-Step Search Algorithm (NTS) can be used as methods for calculating motion vectors. The motion vector may have a motion vector value of 1/2 or 1/4 pixel unit based on the interpolated pixel. The motion prediction unit can predict the current prediction unit by making the motion prediction method different. Various methods such as a skip method, a merge method, an AMVP (Advanced Motion Vector Prediction) method, and an Intra Block Copy method can be used as the motion prediction method.

The intra prediction unit 125 can generate a prediction unit based on reference pixel information around the current block which is pixel information in the current picture. In the case where the neighboring block of the current prediction unit is the block in which the inter prediction is performed so that the reference pixel is the pixel performing the inter prediction, the reference pixel included in the block in which the inter prediction is performed is referred to as the reference pixel Information. That is, when the reference pixel is not available, the reference pixel information that is not available may be replaced by at least one reference pixel among the available reference pixels.

In intra prediction, the prediction mode may have a directional prediction mode in which reference pixel information is used according to a prediction direction, and a non-directional mode in which direction information is not used in prediction. The mode for predicting the luminance information may be different from the mode for predicting the chrominance information and the intra prediction mode information or predicted luminance signal information used for predicting the luminance information may be utilized to predict the chrominance information.

When intraprediction is performed, when the size of the prediction unit is the same as the size of the conversion unit, intra prediction is performed on the prediction unit based on pixels existing on the left side of the prediction unit, pixels existing on the upper left side, Can be performed. However, when intra prediction is performed, when the size of the prediction unit differs from the size of the conversion unit, intraprediction can be performed using the reference pixel based on the conversion unit. It is also possible to use intraprediction using NxN partitioning only for the minimum encoding unit.

The intra prediction method can generate a prediction block after applying an AIS (Adaptive Intra Smoothing) filter to the reference pixel according to the prediction mode. The type of the AIS filter applied to the reference pixel may be different. In order to perform the intra prediction method, the intra prediction mode of the current prediction unit can be predicted from the intra prediction mode of the prediction unit existing around the current prediction unit. In the case where the prediction mode of the current prediction unit is predicted using the mode information predicted from the peripheral prediction unit, if the intra prediction mode of the current prediction unit is the same as the intra prediction mode of the current prediction unit, The prediction mode information of the current block can be encoded by performing entropy encoding if the prediction mode of the current prediction unit is different from the prediction mode of the neighbor prediction unit.

In addition, a residual block including a prediction unit that has been predicted based on the prediction unit generated by the prediction units 120 and 125 and a residual value that is a difference value from the original block of the prediction unit may be generated. The generated residual block may be input to the transform unit 130. [

The transform unit 130 transforms the residual block including the residual information of the prediction unit generated through the original block and the predictors 120 and 125 into a DCT (Discrete Cosine Transform), a DST (Discrete Sine Transform), a KLT You can convert using the same conversion method. The decision to apply the DCT, DST, or KLT to transform the residual block may be based on the intra prediction mode information of the prediction unit used to generate the residual block.

The quantization unit 135 may quantize the values converted into the frequency domain by the conversion unit 130. [ The quantization factor may vary depending on the block or the importance of the image. The values calculated by the quantization unit 135 may be provided to the inverse quantization unit 140 and the reorder unit 160.

The reordering unit 160 can reorder the coefficient values with respect to the quantized residual values.

The reordering unit 160 may change the two-dimensional block type coefficient to a one-dimensional vector form through a coefficient scanning method. For example, the rearranging unit 160 may scan a DC coefficient to a coefficient in a high frequency region using a Zig-Zag scan method, and change the DC coefficient to a one-dimensional vector form. Instead of the jig-jag scan, a vertical scan may be used to scan two-dimensional block type coefficients in a column direction, and a horizontal scan to scan a two-dimensional block type coefficient in a row direction depending on the size of the conversion unit and the intra prediction mode. That is, it is possible to determine whether any scanning method among the jig-jag scan, the vertical direction scan and the horizontal direction scan is used according to the size of the conversion unit and the intra prediction mode.

The entropy encoding unit 165 may perform entropy encoding based on the values calculated by the reordering unit 160. For entropy encoding, various encoding methods such as Exponential Golomb, Context-Adaptive Variable Length Coding (CAVLC), and Context-Adaptive Binary Arithmetic Coding (CABAC) may be used.

The entropy encoding unit 165 receives the residual value count information of the encoding unit, the block type information, the prediction mode information, the division unit information, the prediction unit information and the transmission unit information, and the motion information of the motion unit from the reordering unit 160 and the prediction units 120 and 125 Vector information, reference frame information, interpolation information of a block, filtering information, and the like.

The entropy encoding unit 165 can entropy-encode the coefficient value of the encoding unit input by the reordering unit 160. [

The inverse quantization unit 140 and the inverse transformation unit 145 inverse quantize the quantized values in the quantization unit 135 and inversely transform the converted values in the conversion unit 130. [ The residual value generated by the inverse quantization unit 140 and the inverse transform unit 145 is combined with the prediction unit predicted through the motion estimation unit, the motion compensation unit and the intra prediction unit included in the prediction units 120 and 125, A block (Reconstructed Block) can be generated.

The filter unit 150 may include at least one of a deblocking filter, an offset correction unit, and an adaptive loop filter (ALF).

The deblocking filter can remove block distortion caused by the boundary between the blocks in the reconstructed picture. It may be determined whether to apply a deblocking filter to the current block based on pixels included in a few columns or rows included in the block to determine whether to perform deblocking. When a deblocking filter is applied to a block, a strong filter or a weak filter may be applied according to the deblocking filtering strength required. In applying the deblocking filter, horizontal filtering and vertical filtering may be performed concurrently in performing vertical filtering and horizontal filtering.

The offset correction unit may correct the offset of the deblocked image with respect to the original image in units of pixels. In order to perform offset correction for a specific picture, pixels included in an image are divided into a predetermined number of areas, and then an area to be offset is determined and an offset is applied to the area. Alternatively, Can be used.

Adaptive Loop Filtering (ALF) can be performed based on a comparison between the filtered reconstructed image and the original image. After dividing the pixels included in the image into a predetermined group, one filter to be applied to the group may be determined and different filtering may be performed for each group. The information related to whether to apply the ALF may be transmitted for each coding unit (CU), and the shape and the filter coefficient of the ALF filter to be applied may be changed according to each block. Also, an ALF filter of the same type (fixed form) may be applied irrespective of the characteristics of the application target block.

The memory 155 may store the reconstructed block or picture calculated through the filter unit 150 and the reconstructed block or picture stored therein may be provided to the predictor 120 or 125 when the inter prediction is performed.

2 is a block diagram illustrating an image decoding apparatus according to an embodiment of the present invention.

2, the image decoder 200 includes an entropy decoding unit 210, a reordering unit 215, an inverse quantization unit 220, an inverse transform unit 225, prediction units 230 and 235, 240, and a memory 245 may be included.

When an image bitstream is input in the image encoder, the input bitstream may be decoded in a procedure opposite to that of the image encoder.

The entropy decoding unit 210 can perform entropy decoding in a procedure opposite to that in which entropy encoding is performed in the entropy encoding unit of the image encoder. For example, various methods such as Exponential Golomb, Context-Adaptive Variable Length Coding (CAVLC), and Context-Adaptive Binary Arithmetic Coding (CABAC) may be applied in accordance with the method performed by the image encoder.

The entropy decoding unit 210 may decode information related to intra prediction and inter prediction performed in the encoder.

The reordering unit 215 can perform reordering based on a method in which the entropy decoding unit 210 rearranges the entropy-decoded bitstreams in the encoding unit. The coefficients represented by the one-dimensional vector form can be rearranged by restoring the coefficients of the two-dimensional block form again. The reordering unit 215 can perform reordering by receiving information related to the coefficient scanning performed by the encoding unit and performing a reverse scanning based on the scanning order performed by the encoding unit.

The inverse quantization unit 220 can perform inverse quantization based on the quantization parameters provided by the encoder and the coefficient values of the re-arranged blocks.

The inverse transform unit 225 may perform an inverse DCT, an inverse DST, and an inverse KLT on the DCT, DST, and KLT transformations performed by the transform unit on the quantization result performed by the image encoder. The inverse transform can be performed based on the transmission unit determined by the image encoder. In the inverse transform unit 225 of the image decoder, a transform technique (e.g., DCT, DST, KLT) may be selectively performed according to a plurality of information such as a prediction method, a size of a current block, and a prediction direction.

The prediction units 230 and 235 can generate a prediction block based on the prediction block generation related information provided by the entropy decoding unit 210 and the previously decoded block or picture information provided in the memory 245. [

As described above, when intra prediction is performed in the same manner as in the image encoder, when the size of the prediction unit is the same as the size of the conversion unit, pixels existing on the left side of the prediction unit, pixels existing on the upper left side, However, when the size of the prediction unit differs from the size of the prediction unit in intra prediction, intraprediction is performed using a reference pixel based on the conversion unit . It is also possible to use intra prediction using NxN division only for the minimum coding unit.

The prediction units 230 and 235 may include a prediction unit determination unit, an inter prediction unit, and an intra prediction unit. The prediction unit determination unit receives various information such as prediction unit information input from the entropy decoding unit 210, prediction mode information of the intra prediction method, motion prediction related information of the inter prediction method, and identifies prediction units in the current coding unit. It is possible to determine whether the unit performs inter prediction or intra prediction. The inter prediction unit 230 predicts the current prediction based on the information included in at least one of the previous picture of the current picture or the following picture including the current prediction unit by using information necessary for inter prediction of the current prediction unit provided by the image encoder, Unit can be performed. Alternatively, the inter prediction may be performed on the basis of the information of the partial region previously reconstructed in the current picture including the current prediction unit.

In order to perform inter prediction, a motion prediction method of a prediction unit included in a corresponding encoding unit on the basis of an encoding unit includes a skip mode, a merge mode, an AMVP mode, and an intra block copy mode It is possible to judge whether or not it is any method.

The intra prediction unit 235 can generate a prediction block based on the pixel information in the current picture. If the prediction unit is a prediction unit that performs intra prediction, the intra prediction can be performed based on the intra prediction mode information of the prediction unit provided by the image encoder. The intraprediction unit 235 may include an AIS (Adaptive Intra Smoothing) filter, a reference pixel interpolator, and a DC filter. The AIS filter performs filtering on the reference pixels of the current block and can determine whether to apply the filter according to the prediction mode of the current prediction unit. The AIS filtering can be performed on the reference pixel of the current block using the prediction mode of the prediction unit provided in the image encoder and the AIS filter information. When the prediction mode of the current block is a mode in which AIS filtering is not performed, the AIS filter may not be applied.

The reference pixel interpolator may interpolate the reference pixels to generate reference pixels in units of pixels less than or equal to an integer value when the prediction mode of the prediction unit is a prediction unit that performs intra prediction based on pixel values obtained by interpolating reference pixels. The reference pixel may not be interpolated in the prediction mode in which the prediction mode of the current prediction unit generates the prediction block without interpolating the reference pixel. The DC filter can generate a prediction block through filtering when the prediction mode of the current block is the DC mode.

The restored block or picture may be provided to the filter unit 240. The filter unit 240 may include a deblocking filter, an offset correction unit, and an ALF.

When information on whether a deblocking filter is applied to a corresponding block or picture from the image encoder or a deblocking filter is applied, information on whether a strong filter or a weak filter is applied can be provided. In the deblocking filter of the video decoder, the deblocking filter related information provided by the video encoder is provided, and the video decoder can perform deblocking filtering for the corresponding block.

The offset correction unit may perform offset correction on the reconstructed image based on the type of offset correction applied to the image and the offset value information during encoding.

The ALF can be applied to an encoding unit on the basis of ALF application information and ALF coefficient information provided from an encoder. Such ALF information may be provided in a specific parameter set.

The memory 245 may store the reconstructed picture or block to be used as a reference picture or a reference block, and may also provide the reconstructed picture to the output unit.

As described above, in the embodiment of the present invention, a coding unit (coding unit) is used as a coding unit for convenience of explanation, but it may be a unit for performing not only coding but also decoding.

The current block indicates a block to be coded / decoded. Depending on the coding / decoding step, the current block includes a coding tree block (or coding tree unit), a coding block (or coding unit), a transform block (Or prediction unit), and the like.

One picture may be divided into a square block or a non-square basic block and then encoded / decoded. At this time, the basic block may be referred to as a coding tree unit. The coding tree unit may be defined as a coding unit of the largest size allowed by a sequence or a slice. Information regarding whether the coding tree unit is square or non-square or about the size of the coding tree unit can be signaled through a sequence parameter set, a picture parameter set, or a slice header. The coding tree unit can be divided into smaller size partitions. In this case, if the partition generated by dividing the coding tree unit is depth 1, the partition created by dividing the partition having depth 1 can be defined as depth 2. That is, the partition created by dividing the partition having the depth k in the coding tree unit can be defined as having the depth k + 1.

A partition of arbitrary size generated as the coding tree unit is divided can be defined as a coding unit. The coding unit may be recursively divided or divided into basic units for performing prediction, quantization, transformation, or in-loop filtering, and the like. In one example, a partition of arbitrary size generated as a coding unit is divided may be defined as a coding unit, or may be defined as a conversion unit or a prediction unit, which is a basic unit for performing prediction, quantization, conversion or in-loop filtering and the like.

The partitioning of the coding tree unit or the coding unit may be performed based on at least one of a vertical line and a horizontal line. Further, the number of vertical lines or horizontal lines partitioning the coding tree unit or the coding unit may be at least one or more. As an example, one vertical line or one horizontal line may be used to divide a coding tree unit or coding unit into two partitions, or two vertical lines or two horizontal lines to divide a coding tree unit or a coding unit into three partitions Can be divided. Alternatively, one vertical line and one horizontal line may be used to divide the coding tree unit or the coding unit into four partitions having a length and a width of 1/2.

When dividing the coding tree unit or the coding unit into a plurality of partitions using at least one vertical line or at least one horizontal line, the partitions may have a uniform size or may have different sizes. Alternatively, any one partition may have a size different from the remaining partitions.

In the following embodiments, it is assumed that a coding tree unit or a coding unit is divided into a quad tree or a binary tree structure. However, it is also possible to divide a coding tree unit or a coding unit using a larger number of vertical lines or a larger number of horizontal lines.

FIG. 3 illustrates an example in which a coding block is hierarchically divided based on a tree structure according to an embodiment to which the present invention is applied.

The input video signal is decoded in a predetermined block unit, and a basic unit for decoding the input video signal is called a coding block. The coding block may be a unit for performing intra / inter prediction, conversion, and quantization. Further, a prediction mode (for example, an intra-picture prediction mode or an inter-picture prediction mode) is determined for each coding block, and the prediction blocks included in the coding block can share the determined prediction mode. The coding block may be a square or non-square block having any size falling within the range of 8x8 to 64x64, and may be a square or non-square block having a size of 128x128, 256x256 or more.

Specifically, the coding block may be hierarchically partitioned based on at least one of a quad tree and a binary tree. Herein, the quadtree-based partitioning may be a method in which a 2Nx2N coding block is divided into 4 NxN coding blocks, and a binary tree-based partitioning may be a method in which one coding block is divided into 2 coding blocks. Even if the binary tree-based partitioning is performed, a square-shaped coding block may exist in the lower depth.

Binary tree based partitioning may be performed symmetrically or asymmetrically. The coding block divided based on the binary tree may be a square block or a non-square block such as a rectangle. As an example, the partition type in which binary tree-based partitioning is allowed is a symmetric 2NxN (horizontal direction non-puncturing unit) or Nx2N (vertical direction non-puncturing coding unit) as in the example shown in FIG. 4, And may include at least one of nLx2N, nRx2N, 2NxnU, and 2NxnD, which are asymmetric.

Binary tree-based partitioning may be limited to either a symmetric or an asymmetric partition. In this case, configuring the coding tree unit as a square block corresponds to quad tree CU partitioning, and configuring the coding tree unit as a symmetric non-square block may correspond to binary tree partitioning. Constructing the coding tree unit as a square block and a symmetric non-square block may correspond to quad and binary tree CU partitioning.

Binary tree-based partitioning can be performed on a coded block where quadtree-based partitioning is no longer performed. Quadtree-based partitioning may no longer be performed for coded blocks that are partitioned on a binary tree basis.

In addition, the division of the lower depth can be determined depending on the division type of the upper depth. For example, if binary tree-based partitioning is allowed in two or more depths, only binary tree-based partitioning of the same type as the binary tree partitioning of the upper depths may be allowed in the lower depths. For example, if the binary tree-based partitioning is performed in the 2NxN type in the upper depth, 2NxN type binary tree-based partitioning can be performed even in the lower depth. Alternatively, if the binary tree-based partitioning is performed in the Nx2N type in the upper depth, the binary tree-based partitioning in the Nx2N type may be allowed in the lower depths.

Conversely, it is also possible to allow only a binary tree-based partition of a type different from the binary tree partition type of the upper depth in the lower depth.

For a sequence, slice, coding tree unit or coding unit, it may be possible to limit only certain types of binary tree based partitioning to be used. As an example, only binary tree-based partitioning in the form of 2NxN or Nx2N for the coding tree unit is allowed to be allowed. The allowed partition type may be predefined in an encoder or a decoder, or may be signaled through a bitstream by encoding information on an acceptable partition type or an unacceptable partition type.

5 is a diagram showing an example in which only a specific type of binary tree-based partition is allowed. FIG. 5A shows an example in which only binary tree-based partitioning in the form of Nx2N is allowed, and FIG. 5B shows an example in which only binary tree-based partitioning in the form of 2NxN is allowed to be allowed. In order to implement the adaptive partitioning based on the quadtree or the binary tree, information indicating quad tree-based partitioning, information on the size / depth of the quadtree based partitioning allowable coding block, Information about the size / depth of a coding block in which binary tree-based partitioning is allowed, information on the size / depth of a coding block in which binary tree-based partitioning is not allowed, or whether the binary tree- Information regarding the horizontal direction, and the like can be used.

Also, for the coding tree unit or the predetermined coding unit, the number of times the binary tree division is permitted, the depth at which the binary tree division is allowed, or the number of the depths at which the binary tree division is permitted can be obtained. The information may be encoded in units of a coding tree unit or a coding unit, and may be transmitted to a decoder through a bitstream.

For example, a syntax 'max_binary_depth_idx_minus1' indicating the maximum depth at which binary tree segmentation is allowed may be encoded / decoded through a bitstream, via a bitstream. In this case, max_binary_depth_idx_minus1 + 1 may indicate the maximum depth at which the binary tree division is allowed.

Referring to the example shown in FIG. 6, in FIG. 6, a binary tree division is performed for a depth 2 coding unit and a depth 3 coding unit. Accordingly, the information indicating the number of times (2) the binary tree segmentation in the coding tree unit has been performed, the information indicating the maximum depth (depth 3) allowed to divide the binary tree in the coding tree unit, or the binary tree segmentation in the coding tree unit At least one of information indicating the number of allowed depths (2, depth 2 and depth 3) can be encoded / decoded through a bitstream.

As another example, at least one of the number of times the binary tree partition is allowed, the depth at which the binary tree partition is allowed, or the number of the depths at which the binary tree partition is allowed is obtained for each sequence and slice. For example, the information may be encoded in a sequence, picture, or slice unit and transmitted through a bitstream. Accordingly, the first slice and the second slice may differ in at least one of the number of times the binary tree is divided, the maximum depth allowed for binary tree division, or the number of depths allowed for binary tree division. In one example, in the first slice, binary tree segmentation is allowed in only one depth, while in the second slice, binary tree segmentation in two depths is allowed.

As another example, it is also possible to set at least one of the number of times the binary tree division is permitted, the depth at which the binary tree division is allowed, or the number of the depths at which the binary tree division is allowed according to the time level identifier (TemporalID) have. Here, the temporal level identifier (TemporalID) is used to identify each of a plurality of layers of an image having a scalability of at least one of view, spatial, temporal or picture quality will be.

As shown in FIG. 3, the first coding block 300 having a split depth k may be divided into a plurality of second coding blocks based on a quad tree. For example, the second coding blocks 310 to 340 may be square blocks having half the width and height of the first coding block, and the division depth of the second coding block may be increased to k + 1.

The second coding block 310 having the division depth k + 1 may be divided into a plurality of third coding blocks having a division depth k + 2. The division of the second coding block 310 may be performed using a quadtree or a binary tree selectively according to the division method. Here, the partitioning scheme may be determined based on at least one of information indicating partitioning based on a quadtree or information indicating partitioning based on a binary tree.

When the second coding block 310 is divided based on quadtrees, the second coding block 310 is divided into four third coding blocks 310a having half the width and height of the second coding block, and the third coding block 310a The split depth can be increased to k + 2. On the other hand, when the second coding block 310 is divided based on the binary tree, the second coding block 310 may be divided into two third coding blocks. At this time, each of the two third coding blocks is a non-square block in which one of the width and height of the second coding block is half, and the dividing depth can be increased to k + 2. The second coding block may be determined as a non-square block in the horizontal direction or the vertical direction according to the dividing direction, and the dividing direction may be determined based on information on whether the dividing based on the binary tree is the vertical direction or the horizontal direction.

Meanwhile, the second coding block 310 may be determined as a last coding block that is not further divided based on a quadtree or a binary tree. In this case, the coding block may be used as a prediction block or a transform block.

The third coding block 310a may be determined as a terminal coding block as well as the division of the second coding block 310, or may be further divided based on a quadtree or a binary tree.

The third coding block 310b divided on the basis of the binary tree may be further divided into a vertical coding block 310b-2 or a horizontal coding block 310b-3 on the basis of a binary tree, The division depth of the block can be increased to k + 3. Alternatively, the third coding block 310b may be determined as a last coding block 310b-1 that is not further divided based on the binary tree, and the corresponding coding block 310b-1 may be used as a prediction block or a transform block . However, the above-described partitioning process may include information on the size / depth of a coding block in which quadtree-based partitioning is allowed, information on the size / depth of a coding block in which binary tree-based partitioning is allowed or binary tree- / RTI > information about the size / depth of the coding block that is not coded.

The size that the coding block can have is limited to a predetermined number, or the size of the coding block in a predetermined unit may have a fixed value. As an example, the size of a coding block in a sequence or the size of a coding block in a picture may be limited to 256x256, 128x128, or 32x32. Information indicating the size of a sequence or an intra-picture coding block may be signaled through a sequence header or a picture header.

As a result of the division based on the quadtree and the vital tree, the coding unit can be square or any size rectangular.

The coding block is coded using at least one of a skip mode, an intra picture prediction, an inter picture prediction or a skip method. Once a coding block is determined, a prediction block can be determined through predictive partitioning of the coding block. Predictive partitioning of the coded block can be performed by a partition mode (Part_mode) indicating the partition type of the coded block. The size or shape of the prediction block may be determined according to the partition mode of the coding block. For example, the size of the prediction block determined according to the partition mode may be equal to or smaller than the size of the coding block.

7 is a diagram illustrating a partition mode that can be applied to a coding block when a coding block is coded by inter-picture prediction.

If the coding block is coded as an inter-picture prediction, one of eight partitioning modes may be applied to the coding block, as in the example shown in Fig.

If the coding block is coded in the intra prediction, the coding mode can be applied to the partition mode PART_2Nx2N or PART_NxN.

PART_NxN may be applied when the coding block has a minimum size. Here, the minimum size of the coding block may be one previously defined in the encoder and the decoder. Alternatively, information regarding the minimum size of the coding block may be signaled via the bitstream. In one example, the minimum size of the coding block is signaled through the slice header, so that the minimum size of the coding block per slice can be defined.

In general, the size of the prediction block may have a size from 64x64 to 4x4. However, when the coding block is coded by inter-picture prediction, it is possible to prevent the prediction block from having a 4x4 size in order to reduce the memory bandwidth when performing motion compensation.

8 is a flowchart illustrating an inter prediction method according to an embodiment of the present invention.

Referring to FIG. 8, the motion information of the current block can be determined (S810). The motion information of the current block may include at least one of a motion vector relating to the current block, a reference picture index of the current block, or an inter prediction direction of the current block.

The motion information of the current block may be obtained based on at least one of information signaled through a bitstream or motion information of a neighboring block neighboring the current block.

9 is a diagram illustrating a process of deriving motion information of a current block when a merge mode is applied to the current block.

If a merge mode is applied to the current block, a spatial merge candidate may be derived from the spatially neighboring block of the current block (S910). Spatial neighbor blocks may include at least one of the top, left, or adjacent blocks of the current block (e.g., at the top left corner, the top right corner, or the bottom left corner) of the current block.

The motion information of the spatial merge candidate may be set to be the same as the motion information of the spatial neighboring block.

The temporal merge candidate may be derived from the temporally neighboring block of the current block (S920). The temporal neighbor block may refer to a co-located block included in the collocated picture. A collocated picture has a picture order count (POC) different from the current picture including the current block. A collocated picture may be determined by a picture having a predefined index in the reference picture list or by an index signaled from the bitstream. The temporal neighbor block may be determined to be any block in the block having the same position and size as the current block in the collocated picture or a block adjacent to the block having the same position and size as the current block. For example, at least one of a block including a center coordinate of a block having the same position and size as the current block in the collocated picture or a block adjacent to the lower right boundary of the block may be determined as a temporal neighbor block.

The temporal merge candidate motion information may be determined based on motion information of temporally neighboring blocks. In one example, the temporal merge candidate motion vector may be determined based on the motion vector of the temporally neighboring block. In addition, the inter prediction direction of the temporal merge candidate may be set to be the same as the inter prediction direction of the temporal neighbor block. However, the reference picture index of the temporal merge candidate may have a fixed value. For example, the reference picture index of the temporal merge candidate may be set to '0'.

Thereafter, the merge candidate list including the spatial merge candidate and the temporal merge candidate may be generated (S930). If the number of merge candidates included in the remainder candidate list is smaller than the maximum number of merge candidates, a merge candidate having a combined merge candidate combining two or more merge candidates or a (0, 0) motion vector May be included in the merge candidate list.

When the merge candidate list is generated, at least one of merge candidates included in the merge candidate list may be specified based on the merge index (S940).

The motion information of the current block may be set to be the same as the motion information of the merge candidate specified by the merge index (S950). For example, when the spatial merge candidate is selected by the merge index, the motion information of the current block may be set to be the same as the motion information of the spatial neighboring block. Alternatively, when the temporal merge candidate is selected by the merge index, the motion information of the current block may be set to be the same as the motion information of the temporally neighboring block.

10 is a diagram illustrating a process of deriving motion information of a current block when the AMVP mode is applied to the current block.

When the AMVP mode is applied to the current block, at least one of the inter prediction direction of the current block or the reference picture index can be decoded from the bitstream (S1010). That is, when the AMVP mode is applied, at least one of the inter prediction direction of the current block or the reference picture index may be determined based on the information encoded through the bit stream.

The spatial motion vector candidate can be determined based on the motion vector of the spatial neighboring block of the current block (S1020). The spatial motion vector candidate may include at least one of a first spatial motion vector candidate derived from the top neighboring block of the current block and a second spatial motion vector candidate derived from the left neighboring block of the current block. Here, the upper neighbor block includes at least one of the blocks adjacent to the upper or upper right corner of the current block, and the left neighbor block of the current block includes at least one of blocks adjacent to the left or lower left corner of the current block . A block adjacent to the upper left corner of the current block may be treated as a top neighboring block, or it may be treated as a left neighboring block.

If the reference picture between the current block and the spatial neighboring block is different, the spatial motion vector may be obtained by scaling the motion vector of the spatial neighboring block.

The temporal motion vector candidate may be determined based on the motion vector of the temporally neighboring block of the current block (S1030). If the reference picture between the current block and the temporal neighboring block is different, the temporal motion vector may be obtained by scaling the motion vector of the temporal neighboring block.

A motion vector candidate list including a spatial motion vector candidate and a temporal motion vector candidate may be generated (S1040).

When the motion vector candidate list is generated, at least one of the motion vector candidates included in the motion vector candidate list may be specified based on the motion vector indicator that specifies at least one of the motion vector candidate lists (S1050).

The motion vector candidate specified by the information may be set as a motion vector prediction value of the current block and the motion vector difference value may be added to the motion vector prediction value to obtain a motion vector of the current block (S1060). At this time, the motion vector difference value can be parsed through the bit stream.

When the motion information of the current block is acquired, the motion compensation for the current block can be performed based on the obtained motion information (S820). More specifically, motion compensation for the current block can be performed based on the inter prediction direction of the current block, the reference picture index, and the motion vector.

Hereinafter, encoding and decoding of a Motion Sharing Coding Unit (MSCU) and an MSCU according to the present invention will be described with reference to the drawings.

As described above, a coding unit or a coding block corresponds to a basic unit of coding or decoding. That is, a prediction method such as intra prediction or inter prediction is determined in units of coding units. If the coding unit is divided into a plurality of prediction units, the plurality of prediction units in the coding unit share the determined prediction method.

According to this embodiment, the motion information can be shared by a predetermined block unit larger than the coding unit. Hereinafter, such a predetermined block unit is referred to as a motion share coding unit (MSCU). Here, the motion information may include prediction direction information (e.g., unidirectional prediction or bidirectional prediction such as list 0 prediction (L0 prediction) / list 1 prediction (L1 prediction)), spatial motion vector, temporal motion vector, A motion vector indicator, a merge candidate index, a merge candidate list, a reference picture index, or a reference picture list.

In addition, although all motion information used for inter prediction may be shared, only some motion information may be shared.

Further, all the coding units in the motion sharing coding unit share bidirectional prediction, meaning that bidirectional prediction is used in units of motion-shared coding units, only L0 prediction is used during unidirectional prediction, or L1 prediction can be used during unidirectional prediction do.

The image coding apparatus 100 may signal all or a part of the above-mentioned motion information for each coding unit existing in the motion sharing coding unit. When the motion information is not shared, the video decoding apparatus 200 may perform motion compensation by parsing the signaled motion information for each coding unit. If the motion information is shared, all or a part of the motion information of the coding unit at a specific position among the coding units belonging to the motion-shared coding unit (hereinafter referred to as reference coding unit) . At this time, the remaining coding units in the motion-shared coding unit can be subjected to motion compensation using the derived motion information. For example, the remaining coding units may copy and use the signaled motion information as it is, or may use the motion information (e.g., motion vector) by scaling. In the above embodiment, the fact that the motion information is shared by the plurality of coding units means that the motion information of the reference coding unit is used by the remaining coding units in the motion sharing coding unit, or the motion information (e.g., motion vector) .

Alternatively, motion information may be signaled on a motion shared coding unit basis and then be derived by the video decoding apparatus 200. At this time, all the coding units belonging to the corresponding motion sharing coding unit can share the derived motion information.

On the other hand, the above-described motion information is shared by a plurality of coding units belonging to a motion-shared coding unit, and the differential motion vector between the predicted motion vector and the actual motion vector is independently generated for each of the coding units belonging to the motion- .

11 to 15, various embodiments of encoding and decoding an image using an MSCU according to the present invention will be described in detail.

Setting of MSCU

When the coding tree unit includes a non-regular coding unit, the image coding apparatus 100 may set the smallest square block including the coding unit as a motion-sharing coding unit.

11 is a diagram showing an example of a coding tree unit including a non-regular coding unit. The 16x16 size coding tree unit shown in FIG. 11 includes CU0 and CU1 which are non-regular coding units. According to an embodiment of the present invention, a 4x4 block which is the smallest square block including non-regular coding units CU0 and / or CU1 can be set as a motion-shared coding unit. In addition, an 8x8 block, which is the smallest square block containing the non-regular coding unit CU5, can be set as a motion-shared coding unit, which may include CU5, CU6 and CU7.

As another example of setting a motion sharing coding unit, a predefined predetermined size NxM block may be set to motion sharing coding. Where N and M may be 4, 8, 16, 32, or more. N and M may be the same or different. Specifically, for example, the size of the motion shared coding unit may be set to 16x16, where the motion vector may be signaled for each coding unit smaller than 16x16.

12 is a diagram showing a case where an area of a predetermined size is set as a motion-shared coding unit. The 32.times.32 size coding tree unit shown in FIG. 12 includes coding units CU0 to CU8. In the embodiment shown in Fig. 12, the size of the motion shared coding unit is set to 16x16. CU5 (4x32), CU6 (4x32), and CU7 (8x32), which are not included in 16x16, may restrict the sharing of motion information with other coding units.

As another example of setting the motion sharing coding unit, the motion sharing coding unit may be set based on at least one of size information in which the sharing of motion information is permitted, depth information in which the sharing of motion information is permitted, or position information.

In this case, the size information may be defined as a minimum block size or a maximum block size in which motion information is allowed to be shared, or may be defined as a specific size of a square or non-random block. A syntax element indicating a size of either a width or a height may be signaled in the case of a square, and a syntax element indicating a width and a height in the case of non-regularity may be respectively signaled. The syntax may be signaled at at least one level of a sequence, picture, slice, or tile.

The above-described depth information can be defined the same or similar, and can be signaled. That is, it may be defined as a minimum depth or a maximum depth that allows sharing of motion information. A syntax element representing such depth information may be signaled at at least one level of a sequence, a picture, a slice, and a tile.

Further, the motion sharing coding unit can be set based on the position information. For example, a region of a predetermined size adjacent to the boundary of a picture, slice or tile may be set as a motion-shared coding unit.

A syntax parameter log2_mscu_size_minus3 indicating the size of the motion sharing coding unit, such as a sequence parameter header, a picture parameter header, or a slice header can be signaled. If the value of log2_mscu_size_minus3 is 0, the size of the motion-sharing coding unit is 8x8. If the value of log2_mscu_size_minus3 is 1, the size of the motion-sharing coding unit is 16x16. That is, the size of the motion coding unit can be set to (1 << log2_mscu_size_minus3 + 3). Here, &quot; << indicates a bit shift operation.

Optional use of MSCU

Various embodiments for setting the MSCU have been described above. The MSCU set according to the various embodiments described above may optionally be used.

As an example of a method for selectively using the MSCU, a syntax element isUseMSCUflag associated with the MSCU may be signaled. The syntax element isUseMSCUflag indicates whether or not the coding units in the MSCU share motion information. For example, if the value of the syntax element isUseMSCUflag is 1, it indicates that the coding units in the MSCU share the motion information, and if the value of isUseMSCUflag is 0, the coding units in the MSCU do not share the motion information.

13 is a diagram showing an example of a syntax element isUseMSCUflag associated with each MSCU. The coding tree unit shown in Fig. 13 is divided into a plurality of coding units CU0 to CU9. An area of 8x8 size is set as the motion sharing coding unit. That is, the coding tree unit shown in FIG. 13 includes two motion sharing coding units. The first motion-shared coding unit MSCU0 is an area including coding units CU0 to CU4, and the second motion-shared coding unit MSCU1 is an area including coding units CU5 to CU7. The size of the coding unit CU8 and the size of the CU9 are both 8x8, which is equal to the size of the motion sharing coding unit. Therefore, since there is no other coding unit to share motion information, it need not be set as a motion sharing coding unit.

Referring to FIG. 13, the isUseMSCUflag value associated with the MSCU0 is 1, and the isUseMSCUflag value associated with the MSCU1 is 0. That is, the coding units in MSCU0 share motion information, and the coding units in MSCU1 do not share motion information. Thus, the motion information of the coding units in the MSCU1 is derived per coding unit.

On the other hand, in the above-described embodiments, the coding unit is described as an example in which the coding unit is not divided into sub-blocks of smaller size, for example, prediction blocks. However, it goes without saying that the MSCU according to the present invention can be equally applied even if the coding unit is divided into a plurality of subblocks. That is, each prediction block in the MSCU can share motion information.

Image coding using MSCU

FIG. 14 is a flowchart for explaining an embodiment of an image coding method using an MSCU to which the present invention is applied. The encoding method shown in Fig. 14 can be performed by the image encoding apparatus 100 shown in Fig. For example, steps S1100, S1110, and S1120 may be performed by the inter-prediction unit 120 of the image encoding apparatus 100. [ Steps S1130 and S1140 may be performed by the entropy encoding unit 165. [

By the steps S1100 and S1110, the first coding unit and the second coding unit are subjected to motion estimation and motion compensation, respectively, using inter prediction.

If the first coding unit and the second coding unit share the same motion information, it is determined whether the first coding unit and the second coding unit share the same motion information (S1120). If the first coding unit and the second coding unit share the same motion information, (S1130). If it is determined that the first coding unit and the second coding unit do not share motion information, the motion information of the first coding unit and the motion information of the second coding unit are respectively encoded (S1140). Here, the first coding unit and the second coding unit may be adjacent to each other.

(1) the first coding unit and the second coding unit belong to the same motion coded coding unit, (2) all or part of the motion information of the first coding unit And the motion information of the second coding unit are all or a part of the motion information, the two coding units may decide to share the motion information. Alternatively, if the first coding unit and the second coding unit belong to the same motion-shared coding unit, the video coding apparatus 100 determines that the two coding units share motion information, The motion information of the unit or the motion information of the second coding unit may be selected as the shared motion information.

The setting of the motion sharing coding unit can be performed as in the above-described embodiments. That is, whether or not the first coding unit and the second coding unit belong to the same MSCU can determine whether to share motion information. As described above, in the case of including a non-regular coding unit, the smallest square block including the non-regular coding unit may be set as a motion-shared coding unit. Alternatively, a pre-defined size area or a predetermined size area determined according to a syntax indicating the size of the motion-shared coding unit may be set to motion-sharing coding. Alternatively, it may be set based on at least one of the size information in which the sharing of motion information is allowed, the depth information or the position information in which the sharing of the motion information is allowed.

The MSCU set according to various methods as described above can be selectively used. For example, a syntax element indicating whether the coding units in the MSCU share motion information may be encoded and signaled to the video decoding apparatus 200. When a syntax element indicating whether or not motion information is shared is included in the bitstream, a syntax element indicating whether or not the motion information is shared may be encoded together with the shared motion information in S1130.

14, the first coding unit and the second coding unit perform motion estimation and motion compensation (S1100 and S1110), respectively, and then the first coding unit and the second coding unit share the same motion information (S1120). However, step S1120 may be performed first to determine whether to share motion information, and then motion estimation and motion compensation of the first coding unit and / or the second coding unit. That is, it is determined whether the first coding unit and the second coding unit belong to the same Motion Sharing Corning unit, and determines to share motion information if these two coding units belong to the same Motion Sharing Corning unit. Then, after motion estimation and motion compensation of the first coding unit and / or the second coding unit, one of the motion information of the first coding unit or the motion information of the second coding unit may be selected as the shared motion information.

The shared motion information encoded in step S1130 may be all or part of the motion information of the reference coding unit among the coding units belonging to the motion-shared coding unit. At this time, the video decoding apparatus 200 may perform motion compensation for the remaining coding units in the motion-shared coding unit using the shared motion information. For example, the remaining coding units may copy and use the signaled motion information as it is, or may use the motion information (e.g., motion vector) by scaling.

Alternatively, the shared motion information may be coded on a motion-shared coding unit basis. At this time, all the coding units belonging to the corresponding motion sharing coding unit can share the derived motion information.

On the other hand, the differential motion vector between the predicted motion vector and the actual motion vector can be independently signaled for each of the coding units belonging to the motion-shared coding unit.

Image decoding using MSCU

15 is a flowchart illustrating an image decoding method using an MSCU to which the present invention is applied. The decoding method shown in FIG. 15 can be performed by the inter-prediction unit 230 of the video decoding apparatus 200 shown in FIG.

Referring to FIG. 15, a prediction unit of the first coding unit may be derived using the derived motion information (S1500). If, for example, the first coding unit and the second coding unit belong to the same MSCU, using the motion information derived based on the motion information used to derive the prediction unit of the first coding unit, Lt; / RTI &gt; may be derived (S1510). The motion information of the second coding unit, which is motion information derived based on the motion information of the first coding unit, may be motion information that is the same as or a part of the motion information of the first coding unit. Alternatively, motion information of the second coding unit may be derived by scaling motion information of the first coding unit. Here, the first coding unit and the second coding unit may be adjacent to each other.

The determination as to whether or not the motion information of the second coding unit is derived based on the motion information of the first coding unit may be performed by the various methods described above. For example, the video decoding apparatus 200 may determine whether or not the motion information is shared according to whether the first coding unit and the second coding unit belong to the same MSCU. As described above, in the case of including a non-regular coding unit, the smallest square block including the non-regular coding unit may be set as a motion-shared coding unit. Alternatively, a pre-defined size area or a predetermined size area determined according to a syntax indicating the size of the motion-shared coding unit may be set to motion-sharing coding. Alternatively, it may be set based on at least one of the size information in which the sharing of motion information is allowed, the depth information or the position information in which the sharing of the motion information is allowed.

Alternatively, whether or not the motion information is shared can be determined according to the value of the syntax element isUseMSCUflag as described above, which is signaled in units of MSCUs set according to various methods as described above. At this time, this syntax element indicates whether or not the coding units in the MSCU share motion information.

On the other hand, the shared motion information included in the bitstream may be all or a part of the motion information of the reference coding unit which is one of the coding units belonging to the motion sharing coding unit. At this time, the video decoding apparatus 200 may perform motion compensation for the remaining coding units in the motion-shared coding unit using the shared motion information. For example, the remaining coding units may use the motion information of the reference coding unit as it is, or may use the motion information (e.g., motion vector) by scaling.

Alternatively, the shared motion information may be encoded and signaled on a motion shared coding unit basis. At this time, all the coding units belonging to the corresponding motion sharing coding unit can share the derived motion information.

On the other hand, the differential motion vector between the predicted motion vector and the actual motion vector can be independently signaled for each of the coding units belonging to the motion-shared coding unit. In this case, the video decoding apparatus 200 may derive the final motion vector by summing the predicted motion vector derived based on the shared motion information and the differential motion vector signaled included in the bitstream.

Meanwhile, according to an embodiment of the present invention, a motion vector predictor (MVP) may be derived based on a reference coding unit.

As another example, after setting the motion sharing coding unit as one coding unit, the prediction motion vector MVP may be derived based on the motion sharing coding unit.

Although the above-described embodiments have been described on the basis of a series of steps or flowcharts, they do not limit the time-series order of the invention, and may be performed simultaneously or in different orders as necessary. Further, in the above-described embodiments, each of the components (for example, units, modules, etc.) constituting the block diagram may be implemented by a hardware device or software, and a plurality of components may be combined into one hardware device or software . The above-described embodiments may be implemented in the form of program instructions that may be executed through various computer components and recorded in a computer-readable recording medium. The computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. The hardware device may be configured to operate as one or more software modules for performing the processing according to the present invention, and vice versa.

Claims (8)

1. An image decoding method for decoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied,
Deriving a prediction unit of the first coding unit using the motion information; And
And deriving a prediction unit of the second coding unit using the motion information derived based on the motion information used for the prediction unit derivation of the first coding unit. The method according to claim 1,
Further comprising determining whether the first coding unit and the second coding unit belong to the same motion shared coding unit,
If the first coding unit and the second coding unit belong to the same motion coded coding unit, using the derived motion information based on the motion information of the first coding unit to derive the prediction unit of the second coding unit And decodes the decoded image. 3. The method of claim 2,
Wherein if the at least one of the first coding unit or the second coding is a non-regular coding unit, the motion shared coding unit is a square block including the at least one non-regular coding unit A video decoding method. 3. The method of claim 2,
Wherein the first coding unit and the second coding unit share the same motion information according to a syntax element indicating whether coding units in the motion sharing coding unit share motion information. 1. An image encoding method for encoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied,
Performing motion estimation and motion compensation on the first coding unit using inter prediction;
Performing motion estimation and motion compensation on the second coding unit using inter prediction; And
And encoding the shared motion information when the first coding unit and the second coding unit share the same motion information. An image decoding apparatus for decoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied,
Deriving a prediction unit of the first coding unit using the motion information and deriving a prediction unit of the second coding unit using the derived motion information based on the motion information used for the prediction unit derivation of the first coding unit And an inter-prediction unit for performing inter-prediction. 1. An image encoding apparatus for encoding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied,
An inter-prediction unit for deriving a prediction unit of the first coding unit using inter prediction and deriving a prediction unit of the second coding unit using inter prediction; And
And an entropy encoding unit for encoding the shared motion information when the first coding unit and the second coding unit share the same motion information. A video signal bitstream included in the recording medium is encoded by an image coding method for coding an image for each coding unit corresponding to a unit to which inter prediction or intra prediction is applied, Wherein the image coding method comprises the steps of: deriving a prediction unit of a first coding unit using inter prediction; deriving a prediction unit of a second coding unit using inter prediction; And if the first coding unit and the second coding unit share the same motion information, encoding the shared motion information.

Images