KR20120010367A - Apparatuses and methods for encoding/decoding of video using interpolation filter in a precise unit - Google Patents

Abstract

PURPOSE: An image encoding and decoding apparatus and method thereof are provided to improve encoding effects by reducing additional information amounts. CONSTITUTION: An encoding apparatus creates a prediction block by correcting the movement of an inputted image(903). The encoding apparatus selects an interpolation filter which is used for predicting a movement correction screen(905). The encoding apparatus creates residual values by calculating a difference between a current predicting unit and the predicted predicting unit. After the residual value is quantized and changed, the encoding apparatus creates bit streams by encoding entropy(907, 909).

Description

Apparatus and method for image coding / decoding applying precise unit interpolation filter selection

The present invention relates to encoding and decoding of an image, and more particularly, to an image encoding / decoding apparatus and method applicable to inter prediction encoding / decoding of an image.

In general, an image compression method uses inter prediction and intra prediction techniques that remove redundancy of pictures in order to increase compression efficiency.

An image encoding method using inter prediction is a method of compressing an image by removing temporal redundancy among pictures, and a typical motion compensation prediction encoding method is used.

The motion compensation predictive encoding generates a motion vector (MV) by searching a region similar to the block currently encoded in at least one reference picture located before and / or after the currently encoded picture, and generates the motion vector. Discrete Cosine Transform (DCT) transforms a prediction block obtained by performing motion compensation and a residual block of the current block, quantizes it, and then transmits it by entropy encoding.

In the case of motion compensation inter prediction, a motion vector (MV) is generated by dividing one picture into a plurality of blocks having a predetermined size, and motion compensation is performed using the generated motion vector. Individual motion parameters for each prediction block obtained by performing motion compensation are transmitted to the decoder.

Since motion vectors can have non-integer values, motion compensated inter picture prediction requires evaluating pixel values of the reference picture at non-integer positions. Pixel values at non-integer positions are referred to as sub-pixel values and the process of determining these values is called interpolation. The calculation of the sub-pixel values is done by applying filter coefficients to the pixels around the integer pixels of the reference picture. For example, it is predicted using a 6-tap interpolation filter with filter coefficients ((1, -5, 20, 20, -5, 1) / 32) for P picture for H.264 / AVC. In general, when higher order filters are used, better motion prediction performance is obtained, but the amount of transmission of the filter coefficients of the interpolation filter to be transmitted to the decoder increases.

A first object of the present invention is to provide an image encoding method and an encoding apparatus for improving encoding accuracy in a high resolution image having a resolution of HD or higher definition.

A second object of the present invention is to provide an image decoding method and decoding apparatus for improving encoding accuracy in a high resolution image having a resolution of HD or higher definition.

According to an aspect of the present invention, there is provided a method of encoding an image, the method including generating a prediction unit for inter prediction on an input image, and performing motion compensation inter prediction on the prediction unit. And performing the motion compensated inter picture prediction for the prediction unit, wherein the filter used for the motion compensated inter picture prediction is a more precise unit than a picture unit, wherein the precise unit is a slice unit and And selecting at least one of the partition units to calculate sub-pixel values. The performing of the motion compensation inter prediction for the prediction unit may include performing block merge to merge samples belonging to a mergeable block set including neighboring samples of the current block after partitioning the prediction unit with the current block. And calculating the sub-pixel value by selecting the filter information of the filter used for the motion compensation inter prediction, wherein the filter information includes at least one of a filter index and a filter coefficient, for each of the precise units. can do. The same filter information may be allocated to the merged block and transmitted to the decoder. The mergeable block set may include at least one of a block generated by asymmetric partitioning and a block generated by geometrical partitioning.

In addition, the method of decoding an image according to an aspect of the present invention for achieving the second object of the present invention comprises the steps of entropy decoding the received bit stream to dequantize and inverse transform the residual value to restore the residual value, the prediction unit Generating a prediction unit by using the information and the motion parameter; and a unit that is more precise than a picture unit, wherein the unit of precision includes at least one of a slice unit and a partition unit. Information includes at least one of a filter index and a filter coefficient to perform inter prediction on the prediction unit, and reconstruct an image by adding the residual value to the prediction unit on which the inter prediction is performed. Steps. After partitioning the prediction unit, the blocks merged with the current block among the blocks belonging to the mergeable block set may have the same filter information. The filter information may be filter information of a filter used for motion compensation inter prediction. The mergeable block set may include at least one of a block generated by asymmetric partitioning and a block generated by geometrical partitioning. The header information decoded through entropy decoding may include prediction unit information, motion parameter and filter information for motion compensation and prediction.

In addition, the apparatus for decoding an image according to another aspect of the present invention to entropy decode the received bit stream to dequantize the residual value and inverse transform to restore the residual value by inverse quantization and inverse transform unit And a motion compensator for generating a prediction unit using the prediction unit information and the motion parameter, and an adder for reconstructing the image by adding the residual value to the prediction unit, wherein the motion compensator is more precise than the picture unit. The unit includes at least one of a slice unit and a partition unit, and selects and encodes the filtered information by the filter, wherein the filter information includes at least one of a filter index and a filter coefficient. Perform inter prediction.

According to the image encoding / decoding apparatus and method using block merging as described above, an interpolation filter used for motion compensation inter-prediction in a high resolution image having a high definition (HD) or higher resolution is more precise than a picture unit. For example, encoding precision may be improved by selecting a slice unit or a partition unit (the partition unit may include an extended macroblock, a macroblock, or a block).

In addition, when the partition unit is used as the transmission unit of the filter information-the filter index or the filter coefficient of the interpolation filter used for the motion compensation inter prediction, the entire block merged using the block merge is used as the transmission unit of the filter information. By reducing the amount of additional information to be transmitted, the coding efficiency of an image having a high resolution of HD or Ultra HD (Ultra High Definition) or higher can be improved.

1 is a conceptual diagram illustrating a recursive coding unit structure according to an embodiment of the present invention.
2 is a conceptual view illustrating a process of selecting and using a filter in a slice unit according to an embodiment of the present invention.
3 is a conceptual view illustrating a process of selecting and using a filter in a partition unit according to another embodiment of the present invention.
4 is a conceptual diagram illustrating a process of selecting and using a filter in units of asymmetric partitioning according to another embodiment of the present invention.
FIG. 5 illustrates an embodiment of performing geometric partition division having a shape other than square with respect to the prediction unit PU.
6 is a conceptual diagram illustrating a process of selecting and using a filter in a geometric partition unit having a shape other than square according to another embodiment of the present invention.
FIG. 7 is a conceptual diagram illustrating a process of selecting and using a filter in a geometric partition unit having a shape other than square according to another embodiment of the present invention.
FIG. 8 is a conceptual diagram illustrating a process of selecting and using a filter in partition units using block merging according to another embodiment of the present invention.
9 and 10 are conceptual views illustrating a process of selecting and using a filter in partition units using block merging in case of asymmetric partitioning according to another embodiment of the present invention.
FIG. 11 is a conceptual diagram illustrating a process of selecting and using a filter in partition units using block merging in the case of geometric partitioning according to another embodiment of the present invention.
12 and 13 are conceptual views illustrating a process of selecting and using a filter in partition units using block merging in the case of geometric partitioning according to another embodiment of the present invention.
14 is a block diagram illustrating a configuration of an image encoding apparatus for selecting and encoding a filter in units of slices or partitions, according to an embodiment of the present invention.
15 is a flowchart illustrating an image encoding method for selecting and encoding a filter in units of slices or partitions according to an embodiment of the present invention.
16 is a block diagram illustrating a configuration of an image decoding apparatus according to an embodiment of the present invention.
17 is a flowchart illustrating an image decoding method according to an embodiment of the present invention.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

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 the second component, and similarly, the second component may also be referred to as the first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that another component may exist in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

In one embodiment of the present invention, inter-picture / in-picture prediction, transform, quantization, and entropy encoding are performed using an extended macroblock size of 32x32 pixel size or more to apply to a high resolution having a high definition (HD) or higher resolution. Encoding and decoding may be performed, or encoding and decoding may be performed using a recursive coding unit (CU) structure to be described below.

In the following, sub-pixel value interpolation may be applied to both luma and chroma components of an image. In the following description, only the interpolation of the sub-pixel values of the luminance component is described for simplicity.

1 is a conceptual diagram illustrating a recursive coding unit structure according to an embodiment of the present invention.

Referring to FIG. 1, each coding unit CU has a square shape, and each coding unit CU may have a variable size of 2N × 2N (unit pixel) size. Inter prediction, intra prediction, transform, quantization, and entropy encoding may be performed in units of coding units (CUs). The coding unit (CU) may comprise a maximum coding unit (LCU), a minimum coding unit (SCU), the size of the maximum coding unit (LCU), the minimum coding unit (SCU) is a power of two having a size of 8 or more. Can be represented by a value.

Coding unit (CU) according to an embodiment of the present invention may have a circular tree structure. FIG. 1 illustrates a case where the size 2N0 of one side of CU0, which is the maximum coding unit (LCU), is 128 (N0 = 64), and the maximum hierarchical level or hierarchical depth is five. The recursive structure can be represented through a series of flags. For example, when a flag value of a coding unit CUk having a layer level or a layer depth k is 0, the coding for the coding unit CUk is a current layer level. for a level or layer depth, and if the flag value is 1, the coding unit CUk with the current layer level or layer depth k is 4 independent. The coding unit CUk + 1 is divided into a coding unit CUk + 1, and the divided coding unit CUk + 1 has a hierarchical level or layer depth k + 1 and a size Nk + 1 X Nk + 1. . In this case, the coding unit CUk + 1 may be represented as a sub coding unit of the coding unit CUk. The coding unit CUk + 1 is cyclically cycled until the hierarchical level or hierarchical depth of the coding unit CUk + 1 reaches the maximum allowable hierarchical level or hierarchical depth. (recursive) can be processed. If the hierarchical level or hierarchical depth of the coding unit CUk + 1 is the same as the maximum allowable hierarchical level or hierarchical depth, the case of 4 in FIG. 2 is taken as an example. The above division is not allowed.

The size of the largest coding unit (LCU) and the size of the minimum coding unit (SCU) may be included in a sequence parameter set (SPS). The sequence parameter set (SPS) may comprise the maximum allowable layer level or layer depth of the maximum coding unit (LCU). For example, in the case of FIG. 1, when the maximum allowable layer level or layer depth is 5, and the size of one side of the maximum coding unit (LCU) is 128 (unit pixel), 128 X 128 ( LCU), 64 X 64, 32 X 32, 16 X 16 and 8 X 8 (SCU) are available in five different coding unit sizes. That is, the size of the allowable coding unit may be determined given the size of the largest coding unit (LCU) and the maximum allowable layer level or layer depth.

Advantages of using a recursive coding unit structure according to an embodiment of the present invention as described above are as follows.

First, it can support a larger size than the existing 16 X 16 macroblock. If the image region of interest is homogeneous, the large coding unit (LCU) may display the image region of interest with fewer symbols than if using several small blocks.

Second, the codec can be easily optimized for various contents, applications and devices by supporting a maximum coding unit (LCU) having any of various sizes as compared to using fixed size macroblocks. That is, by appropriately selecting the maximum coding unit (LCU) size and the maximum hierarchical level or maximum hierarchical depth, the hierarchical block structure can be further optimized for the target application.

Third, by using a single unit type called a coding unit (LCU) without distinguishing macroblocks, sub-macroblocks, and extended macroblocks, a multilevel hierarchical structure can be defined as a maximum coding unit (LCU) size, a maximum hierarchical level ( It can be represented very simply using level (or maximum layer depth) and a series of flags. When used with a size-independent syntax representation, it is sufficient to specify one generalized size syntax item for the remaining coding tools, which can simplify the actual parsing process, etc. . The maximum value of the hierarchical level (or maximum hierarchical depth) may have a random value and may have a larger value than that allowed in the existing H.264 / AVC coding scheme. Size independent syntax representation can be used to specify all syntax elements in a manner consistent with the size of the coding unit (CU) independent of. The splitting process for the coding unit (CU) can be specified circularly, and other syntax elements for the leaf coding unit-the last coding unit at the layer level-are independent of the coding unit size. Can be defined to be the same size. Such a representation is very effective in reducing parsing complexity, and the clarity of the representation can be improved when a large hierarchical level or hierarchical depth is allowed.

When the hierarchical splitting process is completed, inter-screen prediction or intra-screen prediction may be performed on the end nodes of the coding unit hierarchical tree without further splitting. It is used as a prediction unit (PU) which is a unit.

That is, partition division is performed on the end coding unit for inter prediction or intra prediction. Partitioning is performed for the prediction unit (PU). Here, the prediction unit PU means a basic unit for inter prediction or intra prediction, and may be a conventional macro block unit or a sub-macro block unit, and an extended macro block unit of 32 × 32 pixels or more May be

The information related to the prediction (motion vector, difference value of motion vector, etc.) is transmitted to the decoder for each prediction unit, which is a basic unit of inter prediction.

Partitioning for inter-screen prediction or intra-screen prediction may be performed by asymmetric partitioning, by geometrical partitioning with an arbitrary shape other than square, or by edge direction. It may be made in a partition scheme according to.

In the case of motion compensation inter prediction, a motion vector (MV) is generated by dividing one picture into a plurality of blocks having a predetermined size, and motion compensation is performed using the generated motion vector. Since motion vectors can have non-integer values, motion compensated inter picture prediction uses an interpolation filter to calculate sub-pixel values of the reference picture at non-integer positions. That is, the calculation of the sub-pixel value is done by applying filter coefficients to the pixels around the integer pixels of the reference picture. Using higher order filters results in better motion prediction performance, but increases the amount of transmission of the filter coefficients of the interpolation filter to be transmitted to the decoder.

Accordingly, in the adaptive method of using the interpolation filter according to the embodiments of the present invention, the interpolation filter is more precise than the picture unit based on the experimental result that the optimal interpolation filter in one picture may be different depending on the area within the picture. For example, encoding / decoding is performed by selecting and using a slice unit or a partition unit (the partition unit may include an extended macro block, a macro block, or a block).

Hereinafter, an interpolation filter used for motion compensated inter picture prediction according to embodiments of the present invention is more precise than a picture unit, for example, a slice unit or a partition unit (the partition unit may be an extended macro block or a macro block. Or a block), which will be described in detail.

2 is a conceptual view illustrating a process of selecting and using a filter in a slice unit according to an embodiment of the present invention.

Referring to FIG. 2, the current picture Pt for time t is an optimal one among candidate filters belonging to the candidate filter set CFSt at time t, for example, three filters F1, F2, and F3. Select to use. The plurality of filters may be distinguished from each other by a filter index. The filter index is an identifier for distinguishing selected filters. The filter index may be included in the filter information for the selected filter and transmitted to the decoder. Hereinafter, the filter may be, for example, an interpolation filter used in motion compensation inter prediction.

In addition, an optimal one of the candidate filters belonging to the candidate filter set CFSt at time t in slice units within the current picture Pt for time t, for example, three filters F1, F2, and F3 You can select and use. That is, an optimal filter may be selected for each slice of the current picture Pt, and thus the selected optimal filter may include slice # 0, slice # 1, slice # 2, ... slice #N of the current picture Pt. ) Can be different filters. For example, for slice number 0 (slice # 0) of the current picture Pt, the F1 filter is selected from candidate filters belonging to the candidate filter set CFSt, and slice number 1 (slice # of the current picture Pt) is selected. For 1), the F2 filter may be selected from candidate filters belonging to the candidate filter set CFSt. Alternatively, the selected optimal filter may be the same filter for each slice of the current picture Pt. For example, for slice number 0 of the current picture Pt, the F1 filter is selected from the candidate filters belonging to the candidate filter set CFSt, and for the slice number 1 of the current picture Pt, the candidate filter set CFSt is also selected. The F1 filter may be selected from candidate filters belonging to.

The optimal filter selection for each slice of the current picture Pt may select a filter among filters belonging to a candidate filter set (CFS) according to a rate-distortion optimization criterion.

Select the best one among candidate filters belonging to the candidate filter set CFSt at time t in slice units within the current picture Pt for time t, e.g. three filters F1, F2, F3. As a result, the filter information-the filter index or the filter coefficient-can be transmitted in a slice unit more precisely than the unit of the picture, thereby improving the encoding precision.

3 is a conceptual view illustrating a process of selecting and using a filter in a partition unit according to another embodiment of the present invention.

The partition may include an extended macro block (EMB), a macro block (MB), or a block. The extended macro block size means more than 32 X 32 pixels, and may include, for example, 32 X 32 pixels, 64 X 64 pixels, or 128 X 128 pixels. The macro block size can be, for example, 16 X 16 pixels.

3 illustrates a relationship between partitions and filter indices, for example, when a partition is composed of 64 × 64 pixels, 32 × 32 pixels, and 16 × 16 pixels. The left 64 X 64 partition of FIG. 3 shows a case where the 64 X 64 partition is an extended macro block of size 64 X 64 pixels, and the middle figure of FIG. 3 divides the 64 X 64 partition into four 32 X 32 pixel size partitions. In this case, the partition having a size of 32 X 32 pixels is an extended macro block having a size of 32 X 32 pixels. 3 shows a case where a 64 X 64 partition is divided into four 32 X 32 pixel partitions, and the lower left 32 X 32 partition is divided into four 16 X 16 partitions. This indicates that the partition of is a 32 × 32 pixel extended macroblock and a 16 × 16 pixel partition is a 16 × 16 pixel macroblock.

For example, the left 64 X 64 partition of FIG. 3 is a case in which a 64 X 64 partition is selected as one 64 X 64 block through rate-distortion optimization, and one filter index Ix is selected as the decoder for the 64 X 64 partition. Is sent.

For example, in the middle 64 X 64 partition of FIG. 3, one filter index is transmitted to the decoder for each of the four 32 X 32 partitions. Here, for each of the four 32 X 32 partitions, different filter indices may be selected through rate-distortion optimization as shown in the center of FIG. 3 (Ix0, Ix1, Ix2, Ix3). For some equal or all identical filter indices may be selected through rate-distortion optimization for.

For example, in the right 64 X 64 partition of FIG. 3, one filter index is transmitted to the decoder for each of the three 32 X 32 partitions, and one filter index is transmitted to the decoder for each of the four 32 X 32 partitions. Up to seven filter indices may be used. Here, for each of the four 32 X 32 partitions, different filter indices may be selected through rate-distortion optimization as shown in the center of FIG. 3 (Ix0, Ix1, Ix2, Ix3). For some equal or all identical filter indices may be selected through rate-distortion optimization for.

When a 64 X 64 partition is partitioned into 16 16 X 16 partitions, up to 16 filter indices can be used.

4 is a conceptual diagram illustrating a process of selecting and using a filter in units of asymmetric partitioning according to another embodiment of the present invention.

If the size of the prediction unit (PU) for inter prediction or intra prediction is MXM (M is a natural number, the unit is pixel), asymmetric partition division is performed in the horizontal direction of the coding unit or asymmetric partition division is performed in the vertical direction. can do. In FIG. 4, the size of the prediction unit PU is, for example, 64 × 64.

Referring to FIG. 4, asymmetric partitioning in the horizontal direction is performed to partition the partition P11a having a size of 64 X 16 pixels and P21a having a size of 64 X 48 pixels, or partition P12a having a size of 64 X 48 pixels and a size of 64 X 16 pixels. It can divide into P22a. You can also split the partition asymmetrically in the vertical direction into partitions P13a 16 x 64 pixels and P23a 48 x 64 pixels, or P24a 48 x 64 pixels and P24a 16 x 64 pixels. Can be.

One filter index is transmitted to the decoder for each of the 64 X 16 partition, the 64 X 48 partition, the 16 X 64 partition, and the 48 X 64 partition of FIG. Here, different filter indices may be selected through rate-distortion optimization for each of the 64 X 16 partitions, the 64 X 48 partitions, the 16 X 64 partitions, and the 48 X 64 partitions within the 64 X 64 partitions. It may be chosen.

FIG. 5 illustrates an embodiment of performing geometric partition division having a shape other than square with respect to the prediction unit PU.

Referring to FIG. 5, the boundary line L of the geometric partition for the prediction unit PU may be defined as follows. By dividing the center O of the prediction unit PU into four quadrants using the X and Y axes and drawing a waterline from the center O of the prediction unit PU to the boundary line L, the center of the prediction unit PU All boundary lines in any direction can be specified by the vertical distance ρ from) to the boundary line L and the rotation angle θ from the X axis to the waterline in the counterclockwise direction.

6 is a conceptual diagram illustrating a process of selecting and using a filter in a geometric partition unit having a shape other than square according to another embodiment of the present invention.

Referring to FIG. 6, after dividing a prediction unit (PU) for inter-screen prediction or intra-screen prediction into four quadrants based on the center, the upper left block of the quadrant 2 is divided into partitions P11b and the remaining 1, 3, and 4 quadrants. It is possible to divide the formed '』' block into partition P21b. Alternatively, the lower left block of the three quadrants may be partitioned into partition P12b, and the blocks consisting of the remaining one, two, and four quadrants may be divided into partitions P22b. Alternatively, the upper right block of the first quadrant may be partitioned into partition P13b, and the block consisting of the remaining two, three, and four quadrants may be partitioned into partition P23b. Alternatively, the lower right block of the quadrant 4 may be partitioned into partition P14b, and the block consisting of the remaining 1, 2, and 3 quadrants may be partitioned into partition P24b.

By partitioning the partition into a '-' shape as above, if there are moving objects in the edge block, that is, the upper left, lower left, upper right and lower right blocks, the partition is divided into four blocks more effectively. Encoding can be done. Among the four partitions, a corresponding partition may be selected and used according to which edge block a moving object is located.

Referring to FIG. 6, one filter index may be transmitted to the decoder for each geometric partition. Here, different filter indices may be selected through rate-distortion optimization for each of the geometric partitions, or all the same filter indices may be selected.

FIG. 7 is a conceptual diagram illustrating a process of selecting and using a filter in a geometric partition unit having a shape other than square according to another embodiment of the present invention.

Referring to FIG. 7, the prediction unit PU for inter-screen prediction or intra-screen prediction is divided into two different irregular areas (modes 0 and 1) or divided into rectangular areas of different sizes (modes 2 and 3). ) can do.

Here, the parameter 'pos' is used to indicate the position of the partition boundary. For modes 0 and 1, 'pos' represents the distance in the horizontal direction from the diagonal of the prediction unit PU to the partition boundary. For modes 2 and 3, 'pos' represents the vertical bisector or horizontal of the prediction unit PU. The horizontal distance from the bisector to the partition boundary. In the case of FIG. 4C, mode information may be transmitted to the decoder. Among the four modes, a mode having a minimum RD cost in terms of RD (Rate Distortion) may be used for inter prediction.

Referring to FIG. 7, one filter index may be transmitted to the decoder for each geometric partition. Here, different filter indices may be selected through rate-distortion optimization for each of the geometric partitions, or all the same filter indices may be selected.

The size of the block after partitioning as described above may vary. In addition, the shape of the block after partitioning as described above is asymmetrical, such as a rectangle as shown in Figs. 'You can have a variety of geometric shapes, like shapes, triangles, and so on.

In the case of a high definition image having a high definition (HD) or higher resolution, a unit for transmitting the filter information of the interpolation filter-the filter index or the filter coefficient-is not a unit of picture in order to increase the coding efficiency by increasing the prediction performance when predicting motion compensation. It can be adaptively adjusted in more precise units-slice units, (extended) macro block units, or partition units.

In the case of a high resolution image having a high definition (HD) or higher resolution, the number of blocks per picture increases, so when the filter coefficients are transmitted to the decoder for each partition, the amount of filter information transmitted becomes very large. May be undesirable in Therefore, when the partition unit is used as the transmission unit of the filter information of the interpolation filter used for the motion compensation inter prediction, the amount of additional information to be transmitted to the decoder is reduced by using the entire merged block as the transmission unit using block merging. As a result, encoding efficiency of an image having a high resolution of HD or Ultra HD (Ultra High Definition) or higher can be improved.

FIG. 8 is a conceptual diagram illustrating a process of selecting and using a filter in partition units using block merging according to another embodiment of the present invention.

Referring to FIG. 8, after one picture is hierarchically divided up to an end coding unit, the current block X is merged with a previously encoded Ao block and Bo block so that blocks Ao, Bo, and X are identical motion parameters and / or filters. The information is applied and sent to the decoder. Here, the motion parameter may include, for example, a motion vector, a motion vector difference value, and the like. The filter information may include a filter index and / or a filter coefficient.

In this case, a merging flag indicating whether block merging is applied may be transmitted to the decoder.

Hereinafter, in the case of inter prediction, a set of all prediction blocks is called a temporary block, and a set of blocks that are allowed to merge with a specific block is defined as a mergeable block. The temporary block includes blocks coded up to the current block. The criterion of the mergeable blocks is for example two blocks of the top peripheral samples and the left peripheral samples of the current block, or the top peripheral blocks and the left peripheral blocks of the current block. This can be set in advance. Alternatively, the criterion of the mergeable blocks may be preset to two or more blocks, for example, all of the top peripheral blocks and all of the left peripheral blocks of the current block.

The criteria of the mergeable blocks may be predetermined according to an appointment between the encoder and the decoder. For example, as the default value, the upper and left neighboring samples of the current block are set as described above, and information indicating a criterion of separately mergeable blocks is not transmitted to the decoder. It may be. Alternatively, information indicating a criterion of mergeable blocks may be sent to the decoder.

If a specific block is encoded and the mergeable block is not empty, information on whether or not the mergeable block is to be merged may be transmitted to the decoder.

The set of mergeable blocks may have, for example, at most two elements (the two sample positions, ie the left peripheral sample position and the top peripheral sample position). However, the set of mergeable blocks is not necessarily limited to having only two candidate sample positions or two candidate blocks, and may have two or more candidate sample positions or candidate blocks. Hereinafter, a case in which a mergeable block set has two candidate blocks will be described with reference to FIG. 8.

FIG. 8 illustrates a case in which a picture is divided into prediction blocks by quadtree-based division. The two largest blocks P1 and P2 at the top of FIG. 8 are the macroblocks and are the largest prediction blocks. The remaining blocks of FIG. 8 are obtained by subdivision of the corresponding macroblock. The current block is marked with an 'X'. 8 to 13 illustrate areas encoded before the current block X, and may be the above-mentioned 'temporary block'.

The mergeable block may be generated as follows.

Starting from the top-left sample position of the current block, the left peripheral sample position of the current block and the top peripheral sample position of the current block become candidate block positions for block merging. If the set of mergeable blocks is not empty, a merge flag is sent to the decoder indicating that the current block is merged with the mergeable block. Otherwise, that is, if the merge flag is '0' (false), the motion parameters are transmitted to the decoder without block merging with any one of the temporary blocks as there is no mergeable block. do.

If the merge flag is '1' (true), the following operation is performed. If the mergeable block set includes only one block, one block included in this mergeable block set is used for block merging. If the mergeable block set includes two blocks and the motion parameters of these two blocks are the same, the motion parameters of the two blocks belonging to this mergeable block are also used for the current block. For example, when merge_left_flag is '1' (true), a left peripheral sample position may be selected among the top-left sample positions for the current block X among mergeable block sets, and merge_left_flag is '0' (false). The upper peripheral sample position, which is the remaining of the upper-left sample positions for the current block X, may be selected among the mergeable block set. The motion parameters for the blocks selected as above are also used for the current block.

Referring back to FIG. 8, blocks ('Ao', 'B0' blocks) including direct (top or left) peripheral samples of the top-left sample position may be included in the mergeable block set. Thus, the current block X is merged with block Ao or block Bo. If merge_flag is 0 (false), then the current block X is not merged with either block Ao or block Bo. If block Ao and block Bo have the same motion parameter and / or filter information, there is no need to distinguish the two blocks Ao and Bo since the same result is obtained when merging with either of block Ao and block Bo. . Therefore, merge_left_flag does not need to be sent in this case. Otherwise, if block Ao and block Bo have different motion parameters and / or filter information, if merge_left_flag is 1 then the current block X is merged with block Bo and if merge_left_flag is 0 then current block X is block Ao Is merged with

9 and 10 are conceptual views illustrating a process of selecting and using a filter in partition units using block merging in case of asymmetric partitioning according to another embodiment of the present invention.

9 and 10 illustrate two examples of block merging when the asymmetric partition division of FIG. 4 is used in inter prediction, and is not limited to the case illustrated in FIGS. 9 and 10. It is a matter of course that the block merging according to another embodiment of the present invention may be applied to a combination of the various partition partitioning cases shown.

Referring to FIG. 9, the current block X is merged with block A1b or block B1b belonging to a mergeable block set. If merge_flag is 0 (false), the current block X is not merged with either block A1b or block B1b. If merge_left_flag is '1' (true), block B1b may be selected from the mergeable block set to merge with the current block X, and if merge_left_flag is '0' (false), block A1b merges with the current block X Can be chosen to.

Referring to FIG. 10, the current block X is merged with block A1c or block B1c belonging to a mergeable block set. If merge_flag is 0 (false), the current block X is not merged with either block A1c or block B1c. If merge_left_flag is '1' (true), block B1c may be selected from the mergeable block set to merge with the current block X, and if merge_left_flag is '0' (false), block A1c merges with the current block X Can be chosen to.

9 and 10, the same filter may be selected for block merged asymmetric partitions and the same filter information may be transmitted to the decoder. For example, in FIG. 9, the same filter index Ix2 may be transmitted to the decoder for the merged asymmetric partitions A1b and B1b. In the case of FIG. 10, the same filter index Ix2 may be transmitted to the decoder for the merged asymmetric partitions A1c and B1c.

FIG. 11 is a conceptual diagram illustrating a process of selecting and using a filter in partition units using block merging in the case of geometric partitioning according to another embodiment of the present invention.

FIG. 11 illustrates a block merging in the case of using the geometric partition partitioning of FIG. 6 in inter prediction, and is not limited to the case illustrated in FIG. 11. The combination of the cases of various partition partitioning shown in FIG. Of course, block merge according to another embodiment of the present invention can also be applied to.

Referring to FIG. 11, blocks ('A2' and 'B2' blocks) including upper or left peripheral samples among the upper-left sample positions of the current block X may be included in the mergeable block set. Thus, the current block X is merged with block A2a or block B2a. If merge_flag is 0 (false), the current block X is not merged with either block A2a or block B2a. For example, if merge_left_flag is '1' (true), a block B2a including left peripheral samples of the top-left sample position for the current block X of the mergeable block set may be selected to merge with the current block X and When merge_left_flag is '0' (false), a block A2a including the top peripheral samples remaining among the top-left sample positions for the current block X in the mergeable block set may be selected to merge with the current block X. .

Referring to FIG. 11, the same filter may be selected for block merged geometric partitions, and the same filter information may be transmitted to the decoder. For example, in the case of FIG. 11, the same filter index Ix1 may be transmitted to the decoder for the merged geometric partitions A2a and B2a.

12 and 13 are conceptual views illustrating a process of selecting and using a filter in partition units using block merging in the case of geometric partitioning according to another embodiment of the present invention.

12 and 13 illustrate two examples of block merging when the geometric partition division of FIGS. 5 and 7 is used in inter prediction, and is not limited only to the cases illustrated in FIGS. 12 and 13. It is a matter of course that the block merging according to another embodiment of the present invention can be applied to a combination of the cases of the various geometric partition partitions shown in FIGS. 5 and 7.

Referring to FIG. 12, blocks (“A3a” and “B3a” blocks) including upper or left peripheral samples among the upper-left sample positions of the current block X may be included in the mergeable block set. Thus, the current block X is merged with block A3a or block B3a. If merge_flag is 0 (false), the current block X is not merged with either block A3a or block B3a. For example, if merge_left_flag is '1' (true), block B3a including left neighboring samples of the top-left sample position for the current block X of the mergeable block set may be selected to merge with the current block X and When merge_left_flag is '0' (false), a block A3a including the top peripheral samples remaining among the top-left sample positions for the current block X in the mergeable block set may be selected to merge with the current block X. .

Referring to FIG. 13, the current block X is merged with block A3b or block B3b belonging to a mergeable block set. If merge_flag is 0 (false), the current block X is not merged with either block A3b or block B3b. If merge_left_flag is '1' (true), block B3b may be selected from the mergeable block set to merge with the current block X, and if merge_left_flag is '0' (false), block A3b merges with the current block X Can be chosen to.

12 and 13, the same filter may be selected for block merged geometric partitions, and the same filter information may be transmitted to the decoder. For example, in FIG. 12, the same filter index Ix2 may be transmitted to the decoder for the merged geometric partitions A3a and B3a. For example, in FIG. 13, the same filter index Ix1 may be transmitted to the decoder for the merged geometric partitions A3b and B3b.

14 is a block diagram illustrating a configuration of an image encoding apparatus for selecting and encoding a filter in units of slices or partitions, according to an embodiment of the present invention.

Referring to FIG. 14, the apparatus for encoding an image includes an encoder 630, and the encoder 630 includes an inter prediction unit 632, an intra prediction unit 635, a subtractor 637, a transformer 639, and quantization. The unit 641 may include an entropy encoder 643, an inverse quantizer 645, an inverse transform unit 647, an adder 649, and a frame buffer 651. The inter prediction predictor 632 includes a motion predictor 631 and a motion compensator 633.

The encoder 630 performs encoding on the input image. The input image may be used for inter prediction in the inter prediction unit 632 or intra prediction in the intra prediction unit 635 in units of prediction units (PUs).

The size of the prediction unit applied to the inter prediction or intra prediction may be determined according to the temporal frequency characteristics of the stored frame (or picture) after storing the input image in a buffer (not shown) provided in the encoder. For example, the prediction unit determiner 610 analyzes time-frequency characteristics of the n-th frame (or picture) and the n-th frame (or picture), and the first threshold value in which the analyzed time frequency characteristic value is preset. If it is less than the size of the prediction unit is determined to be 64x64 pixels, and if the analyzed time frequency characteristic value is greater than or equal to the preset first threshold value and less than the second threshold value, the size of the prediction unit is determined to be 32x32 pixels, and the analyzed time frequency When the characteristic value is greater than or equal to a second preset threshold, the size of the prediction unit may be determined to be 16x16 pixels or less. Here, the first threshold value may represent a time frequency characteristic value when the amount of change between frames (or pictures) is smaller than the second threshold value.

The size of the prediction unit applied to the inter prediction or intra prediction may be determined according to the spatial frequency characteristic of the stored frame (or picture) after storing the input image in a buffer (not shown) provided in the encoder. For example, when the image flatness or uniformity of the input frame (or picture) is high, the size of the prediction unit is set to be larger than 32x32 pixels, and when the image flatness or uniformity of the frame (or picture) is low (that is, If the spatial frequency is high), the size of the prediction unit can be set small to 16x16 pixels or less.

Although not shown in FIG. 8, the operation of determining the size of the prediction unit is performed by a coding controller (not shown) by receiving the input image or by a separate prediction unit determination unit (not shown) by receiving the input image. May be For example, the size of the prediction unit may have a size of 16x16 pixels or less, a 32x32 pixel size, and a 64x64 pixel size.

As described above, prediction unit information including the prediction unit size determined for inter-screen prediction or intra-screen prediction is provided to the entropy encoder 643, and is provided to the encoder 630 in units of prediction units having the determined size. In detail, when encoding and decoding using an extended macroblock and an extended macroblock size, the prediction block information may include macroblock size information or extended macroblock size information. In this case, the extended macroblock size may be 32x32 pixels or more, and may include, for example, 32x32 pixels, 64x64 pixels, or 128x128 pixels. When encoding and decoding are performed using the aforementioned recursive coding unit (CU), prediction unit information is an end coding unit to be used for inter prediction or intra prediction instead of the size information of the macro block. The size information of the LCU, that is, the size information of the prediction unit may be included, and further, the prediction unit information may further include the size of the largest coding unit (LCU), the size of the minimum coding unit (SCU), and the maximum allowable hierarchical level. ), Or may further include layer depth and flag information.

The encoder 630 performs encoding on the prediction unit having the determined size.

The inter prediction unit 632 divides the provided prediction unit to be encoded using a partition partitioning method such as asymmetric partitioning, geometric partitioning, and the like, and estimates motion in units of the partitioned block to generate a motion vector. do.

The motion predictor 631 divides the provided current prediction unit by using the aforementioned various partition partitioning methods, and includes at least one reference picture (frame buffer) located before and / or after a picture currently encoded for each partitioned block. In step 651, encoding is completed and stored), a region similar to a partitioned block currently encoded is generated and a motion vector is generated in units of blocks. In this case, the size of the block used for the motion estimation may vary, and when the asymmetric partition and the geometric partition partition according to the embodiments of the present invention are applied, the shape of the block is not only a conventional square shape. 2 to 3c may have an asymmetrical shape such as a rectangle, a 'b' shape, a triangular shape, or the like.

The motion compensator 633 generates a prediction block (or predicted prediction unit) obtained by performing motion compensation using the motion vector generated from the motion predictor 631 and the reference picture.

As described above, the inter-screen prediction unit 632 may use the interpolation filter used for the motion-compensated inter-picture prediction to be more precise than a picture unit, for example, a slice unit or a partition unit (the partition unit may be an extended macro block, Macroblocks, or blocks)) to select sub-pixel values.

When using the partition unit as a transmission unit of the filter information of the interpolation filter-the filter index or the filter coefficient, the inter prediction unit 632 transmits the motion parameter and / or the filter information to the entire merged block using the aforementioned block merging. Use as a unit.

In addition, the inter prediction unit 632 adaptively selects motion vector precision or pixel precision from 1/2 pel, 1 / 4-pel, and 1/8 pel for the extended macroblock. When the extended macroblock is used, the coding efficiency can be improved. For example, 6-tap interpolation with filter coefficients ((1, -5, 20, 20, -5, 1) / 32) for P pictures when applying 1/2 pel motion vector precision or pixel precision Filters can be used to generate 1/2 pel pixel precision signals. When applying 1/4 pel motion vector precision or pixel precision, a value of 1/2 pel pixel precision signal may be generated, and then a 1/4 pel pixel precision signal may be generated by applying an average filter. When 1/8 pel motion vector precision or pixel precision is applied, a value of 1/4 pel pixel precision signal may be generated, and then 1/8 pel pixel precision signal may be generated by applying an average filter.

The intra predictor 635 performs intra prediction encoding using pixel correlation between blocks. The intra prediction unit 635 performs intra prediction to obtain a prediction block of the current prediction unit by predicting a pixel value from an already encoded pixel value of a block in a current frame (or picture).

The subtractor 637 generates a residual value by subtracting the prediction block (or the predicted prediction unit) and the current block (or the current prediction unit) provided by the motion compensator 633, and the transformer 639 and the quantizer 641. ) Transforms and residuals the residual cosine transform (DCT). Here, the transform unit 639 may perform the transformation based on the prediction unit size information, and may perform the transformation, for example, to a 32x32 or 64x64 pixel size. Alternatively, the transform unit 639 may perform transform in a separate transform unit (TU) unit independently of the prediction unit size information provided from the prediction unit determiner 610. For example, the transform unit (TU) size may range from a minimum of 4 by 4 pixels to a maximum of 64 by 64 pixels. Alternatively, the maximum size of the transform unit (TU) may have a 64x64 pixel size or more, for example 128 × 128 pixel size. The transform unit size information may be included in the transform unit information and transmitted to the decoder.

The entropy encoder 643 entropy encodes header information such as quantized DCT coefficients, motion vectors, determined prediction unit information, partition information, filter information, and transform unit information to generate a bit stream.

The inverse quantizer 645 and the inverse transformer 647 inverse quantizes and inverse transforms the quantized data through the quantizer 641. The adder 649 adds the inverse transformed data and the predictive prediction unit provided by the motion compensator 633 to reconstruct the image and provide the image to the frame buffer 651, and the frame buffer 651 stores the reconstructed image.

15 is a flowchart illustrating an image encoding method for selecting and encoding a filter in units of slices or partitions according to an embodiment of the present invention.

Referring to FIG. 15, when an input image is input to an encoding apparatus (step 901), a prediction unit for inter-screen prediction or intra-picture prediction is partitioned with respect to the input image using the aforementioned various partition partitioning methods. For each partitioned block, a region similar to that of the partitioned block currently encoded is searched for in at least one reference picture (encoded in the frame buffer 651), which is located before and / or after the currently encoded picture. A motion vector is generated in units of blocks, and a prediction block (or a predicted prediction unit) is generated by performing motion compensation using the generated motion vector and the picture (step 903).

Then, the encoding apparatus uses the interpolation filter used for the motion compensated inter picture prediction to be more precise than a picture unit, for example, a slice unit or a partition unit (the partition unit is an extended macro block, a macro block, or a block). May be included) to calculate sub-pixel values (step 905). Specifically, as described above, the encoding apparatus may further filter the filter information (filter index or filter coefficient) of the interpolation filter used for the motion compensated inter-picture prediction to a more precise unit than the picture unit, for example, a slice unit or a partition unit. Select and then calculate and encode sub-pixel values.

When the encoding apparatus uses a partition unit as a transmission unit of filter information-a filter index or a filter coefficient of an interpolation filter, the encoding apparatus uses the entire merged block as a transmission unit of motion parameters and / or filter information using the aforementioned block merging.

In addition, the encoding apparatus uses an extended macroblock by adaptively selecting motion vector precision or pixel precision among 1/2 pel, 1 / 4-pel, and 1/8 pel for the extended macroblock. In this case, the coding efficiency can be increased. For example, 6-tap interpolation with filter coefficients ((1, -5, 20, 20, -5, 1) / 32) for P pictures when applying 1/2 pel motion vector precision or pixel precision Filters can be used to generate 1/2 pel pixel precision signals. When applying 1/4 pel motion vector precision or pixel precision, a value of 1/2 pel pixel precision signal may be generated, and then a 1/4 pel pixel precision signal may be generated by applying an average filter. When 1/8 pel motion vector precision or pixel precision is applied, a value of 1/4 pel pixel precision signal may be generated, and then 1/8 pel pixel precision signal may be generated by applying an average filter.

The encoding apparatus obtains the difference between the current prediction unit and the predicted prediction unit, generates, transforms and quantizes a residual value (step 907), and then includes header information such as quantized DCT coefficients, motion parameters, and filter information. (Or syntax elements) are entropy encoded to generate a bit stream (step 909).

Entropy coding reduces the number of bits needed for the representation of syntax elements. In other words, entropy coding is a lossless operation that aims to minimize the number of bits needed to represent transmitted or stored symbols using the distributional nature of the syntax elements that some symbols occur more often than others.

In the image encoding apparatus and the encoding method according to the embodiments of the present invention, the filter information is transmitted only once for the entire merged block by using block merging instead of transmitting the filter information for each prediction block, thereby reducing the amount of transmission of the filter information. As a result, encoding efficiency of an image having a high resolution of HD or Ultra HD (Ultra High Definition) or higher can be improved.

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

Referring to FIG. 16, a decoding apparatus according to an embodiment of the present invention includes an entropy decoder 731, an inverse quantizer 733, an inverse transformer 735, a motion compensator 737, and an intra predictor 739. And a frame buffer 741 and an adder 743.

The entropy decoder 731 receives the compressed bit stream and performs entropy decoding to generate quantized coefficients. The inverse quantization unit 733 and the inverse transform unit 735 restore the residual values by performing inverse quantization and inverse transformation on the quantized coefficients.

The header information decoded by the entropy decoder 731 may include prediction unit size information, and the prediction unit size may include, for example, an extended macroblock size of 16x16 pixels or 32x32 pixels, 64x64 pixels, or 128x128 pixels. Can be. In addition, the decoded header information may include motion parameter and filter information (filter index or filter coefficient) for motion compensation and prediction. The filter information may include filter information transmitted for each block merged by block merging methods according to embodiments of the present invention.

The motion compensator 737 uses the motion parameter and / or filter information for the prediction unit having the same size as that of the prediction unit encoded using the header information decoded from the bit stream by the entropy decoder 731. Motion compensation is performed to generate predicted prediction units. The motion compensator 737 generates a predicted prediction unit by performing motion compensation using motion parameter and / or filter information transmitted for each block merged by the block merging methods according to the embodiments of the present invention.

In addition, the motion compensation unit 737 adaptively selects a motion vector precision or a pixel precision among 1/2 pel, 1 / 4-pel, and 1/8 pel, and encodes an extended macroblock encoded. Based on the selected pixel precision information, motion compensation is performed on the extended macroblock by adaptively selecting among 1/2 pel, 1 / 4-pel, and 1/8 pel.

The intra predictor 739 performs intra prediction encoding using pixel correlation between blocks. The intra prediction unit 739 performs intra prediction to obtain a prediction block of the current prediction unit by predicting a pixel value from an already encoded pixel value of the block in the current frame (or picture).

The adder 743 reconstructs the image by adding the residual value provided by the inverse transform unit 735 and the predicted prediction unit provided by the motion compensator 737 to provide the frame buffer 741, and the frame buffer 741 Save the restored image. That is, the decoder performs a decoding operation by adding the compressed prediction error (residual value provided by the inverse transform unit) to the prediction unit.

17 is a flowchart illustrating an image decoding method according to an embodiment of the present invention.

Referring to FIG. 17, a decoding apparatus first receives a bit stream from an encoding apparatus (step 1101).

Thereafter, the decoding apparatus performs entropy decoding on the received bit stream (step 1103). Data decoded through entropy decoding includes a residual indicating a difference between the current prediction unit and the predicted prediction unit. The header information decoded through entropy decoding may include additional information such as prediction unit information, motion parameters and / or filter information (filter index or filter coefficient) for motion compensation and prediction. The prediction unit information may include prediction unit size information. The motion parameter and / or filter information may include motion parameter and / or filter information transmitted for each block merged by block merging methods according to embodiments of the present invention.

In the case of encoding and decoding using the above-described recursive coding unit (CU) instead of the encoding and decoding method using the extended macroblock and the extended macroblock size, The prediction unit (PU) information may include the size of the largest coding unit (LCU), the size of the minimum coding unit (SCU), the maximum allowable layer level or layer depth, and flag information. .

The decoding control unit (not shown) receives the information on the size of the prediction unit (PU) applied by the encoding apparatus from the encoding apparatus and according to the size of the prediction unit (PU) applied by the encoding apparatus to be described later, motion compensation decoding or inverse transform or inverse quantization. Can be performed.

The decoding apparatus inverse quantizes and inversely transforms the entropy decoded residual value (step 1105). The inverse transform process may be performed in units of prediction unit sizes (eg, 32x32 or 64x64 pixels).

The decoding apparatus generates the predicted prediction unit by performing inter-screen prediction or intra-screen prediction using prediction unit size information, motion parameters for motion compensation and prediction, filter information, and a previously reconstructed picture (step 1107). The decoding apparatus performs inter-screen prediction or intra-screen prediction using prediction unit size information, motion parameter and / or filter information transmitted for each block merged by the block merging methods according to embodiments of the present invention.

The decoder reconstructs an image by adding an inverse quantized and inverse transformed residual value and a prediction unit predicted through the inter prediction or intra prediction.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

630: encoder 632: inter prediction unit
730: decoder

Claims (14)

In the video encoding method,
Generating a prediction unit for inter prediction on an input image; And
Performing motion compensated inter picture prediction for the prediction unit, wherein performing motion compensated inter picture prediction for the prediction unit includes:
Calculating a sub-pixel value by selecting the filter used for the motion compensation inter prediction according to a unit more precise than a picture unit, wherein the unit of precision includes at least one of a slice unit and a partition unit; Video encoding method. The method of claim 1, wherein performing motion compensation inter prediction on the prediction unit is performed.
Performing block merging after merging partitions for the prediction unit, merging samples belonging to a mergeable block set including neighboring samples of a current block with the current block; And
And selecting filter information of the filter used for the motion compensation inter prediction, wherein the filter information includes at least one of a filter index and a filter coefficient, for each of the precise units, to calculate a sub-pixel value. Image coding method using block merging. The image encoding method according to claim 2, wherein the merged blocks are allocated with the same filter information and transmitted to the decoder. The method of claim 1, wherein the mergeable block set includes at least one of a block generated by asymmetric partitioning and a block generated by geometrical partitioning. Image coding method using block merging. In the video decoding method,
Entropy decoding the received bit stream to inverse quantize and inversely transform the residual to restore the residual;
Generating a prediction unit using the prediction unit information and the motion parameter;
A unit of precision that is more precise than a picture unit, wherein the unit of precision includes at least one of a slice unit and a partition unit, and filter information encoded by selecting the filter information, wherein the filter information includes at least one of a filter index and a filter coefficient. Performing inter prediction on the prediction unit by using the inter prediction; And
And reconstructing an image by adding the residual value to the prediction unit on which the inter prediction is performed. The image decoding method of claim 5, wherein the same filter information is included in a block merged with a current block among blocks belonging to a mergeable block set after partitioning the prediction unit. The method of claim 5, wherein the filter information is filter information of a filter used for motion compensation inter prediction. The method of claim 5, wherein the mergeable block set includes at least one of a block generated by asymmetric partitioning and a block generated by geometrical partitioning. An image decoding method. The image decoding method of claim 5, wherein the header information decoded through entropy decoding includes prediction unit information, motion parameter, and filter information for motion compensation and prediction. In the video decoding apparatus,
An inverse quantization and inverse transform unit for entropy decoding the received bit stream to inverse quantize the residual value and inversely transform the residual value to restore the residual value;
A motion compensator for generating a prediction unit using the prediction unit information and the motion parameter; And
An adder configured to reconstruct an image by adding the residual value to a prediction unit, wherein the motion compensator selects and encodes a unit that is more precise than a picture unit, the precision unit including at least one of a slice unit and a partition unit And perform inter-screen prediction on the prediction unit using the filtered filter information, wherein the filter information includes at least one of a filter index and a filter coefficient. The image decoding apparatus of claim 10, wherein the same filter information is included in a block merged with a current block among blocks belonging to a mergeable block set after partitioning the prediction unit. The apparatus of claim 10, wherein the filter information is filter information of a filter used for motion compensation inter prediction. 11. The method of claim 10, wherein the mergeable block set comprises at least one of a block generated by asymmetric partitioning and a block generated by geometrical partitioning. An image decoding device. The apparatus of claim 10, wherein the header information decoded through entropy decoding includes prediction unit information, motion parameter and filter information for motion compensation and prediction.

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