KR20180080131A - Image decoding method and apparatus using inter picture prediction - Google Patents

Abstract

A video decoding method and apparatus using inter-picture prediction is disclosed. An image decoding method using inter-view prediction includes the steps of receiving a bit stream, acquiring a part of information indicating a motion vector of a current block to be decoded in the received bit stream, Obtaining a motion vector of the current block by determining remaining information, and generating a prediction block of the current block through inter-picture prediction using the motion vector of the current block. Therefore, the efficiency of image encoding and decoding can be improved.

Description

[0001] IMAGE DECODING METHOD AND APPARATUS USING INTER PICTURE PREDICTION [0002]

The present invention relates to a method and an apparatus for decoding an image using inter-picture prediction, and more particularly to a method and apparatus for coding and decoding a motion vector necessary for intra-picture prediction of a current block. To a technique for reducing the number of data or bits exchanged between an encoding apparatus and a decoding apparatus by determining only the remaining information using only a part of information indicating a vector.

Each organization, called ISO / ISE Moving Picture Experts Group (MPEG) and ITU-T Video Coding Experts Group (VCEG), organized Joint Collaborative Team on Video Coding (JCV-VC) Video compression standard technology, HEVC (High Efficiency Video Coding) / ITU-T H.265. ISO / ISE MPEG and ITU-T VCEG have been organizing JVET (Joint Video Exploration Team) at the 22nd JCT-VC Geneva Conference in order to respond to the trend of high-definition video becoming popularized by the rapid development of information and communication technology. , We are actively striving to establish the next generation image compression technology standard for image compression of UHD image quality (Ultra High Definition) which is clearer than HD (High Definition) image quality.

Meanwhile, according to the existing video compression standard technology, a prediction block for a current block to be encoded is generated, and a difference value between a prediction block and a current block is encoded, thereby reducing the amount of data to be coded. An intra prediction method for generating a prediction block for a current block using similarity with a spatially adjacent block and an inter prediction method for generating a prediction block for the current block using the similarity between temporally adjacent blocks .

In this case, the inter-picture prediction uses the motion vector as information indicating a block having similarity in the temporally adjacent picture with respect to the current block. In this case, when the motion vector is directly coded, since the bit value can be very large, the encoder constructs candidate motion vectors using the motion vectors of the neighboring blocks adjacent to the current block, and selects the optimal motion vector And the motion vector of the current block is encoded and transmitted to the decoding apparatus.

However, even when the difference value between the optimal motion vector and the motion vector of the current block is encoded, the bit value consumption reduction effect is small when the optimal motion vector is much different from the motion vector of the current block. Accordingly, there is a need for a method for reducing the amount of information transmitted between the encoding apparatus and the decoding apparatus in order to improve the efficiency of image encoding and decoding.

In order to solve the above problems, an object of the present invention is to provide a picture decoding method using inter picture prediction.

It is another object of the present invention to provide an image decoding apparatus using inter-picture prediction.

According to an aspect of the present invention, there is provided an image decoding method using inter picture prediction.

Here, the image decoding method using inter picture prediction may include receiving a bit stream, obtaining a part of information indicating a motion vector of a current block to be decoded in the received bit stream, Obtaining the motion vector of the current block by determining the remaining information, and generating a prediction block of the current block through inter-picture prediction using the motion vector of the current block.

Here, the information indicating the motion vector of the current block may include at least one of a magnitude of a difference value between a best motion vector selected from two or more candidate motion vectors and a motion vector of the current block, a sign of the difference value, Or the like.

Wherein the step of acquiring a motion vector of the current block includes the steps of: determining whether a magnitude of the difference value corresponds to a preset condition; and if the predetermined condition is satisfied, And determining the sign of the difference value based on the motion vector of the motion vector.

Here, the preset condition may be set based on an interval between adjacent vectors among the two or more candidate motion vectors.

The step of determining whether the magnitude of the differential value corresponds to a predetermined condition may include calculating a value having a largest interval between adjacent vectors and a minimum interval between the adjacent vectors, And comparing the minimum value with the magnitude of the difference value.

Here, the predetermined condition may be set based on an interval obtained by dividing the interval between the adjacent vectors by half.

The obtaining of the motion vector of the current block may include obtaining the difference value using the magnitude of the difference value and the sign of the difference value, calculating a difference value between the first and second motion vectors of the two or more candidate motion vectors, Determining an estimated motion vector of the current block by adding a candidate motion vector, determining whether the estimated motion vector has a coordinate value closest to the first candidate motion vector among the two or more candidate motion vectors, And determining, based on the motion vector, the optimal motion vector.

Here, the step of determining the estimated motion vector and the step of determining may be repeatedly performed by substituting the remaining candidate motion vectors, excluding the first candidate motion vector, into the first candidate motion vector.

The determining of the optimal motion vector may determine the candidate motion vector as the optimal motion vector if the candidate motion vector having the closest coordinate value as a result of the iteration is unique.

Wherein the step of acquiring a motion vector of the current block includes the steps of: determining whether a magnitude of the differential value corresponds to a predetermined condition; and determining whether a motion vector of at least one of the two or more candidate motion vectors From the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

According to another aspect of the present invention, there is provided an image decoding apparatus using inter-picture prediction.

The apparatus for decoding an image using inter-picture prediction may include at least one processor and a memory for storing instructions for instructing the at least one processor to perform at least one step. have.

Wherein the at least one step comprises the steps of: receiving a bitstream; obtaining a part of information indicating a motion vector of a current block to be decoded in the received bitstream; Obtaining a motion vector of the current block by determining a motion vector of the current block, and generating a prediction block of the current block through inter-picture prediction using the motion vector of the current block.

Here, the information indicating the motion vector of the current block may include at least one of a magnitude of a difference value between a best motion vector selected from two or more candidate motion vectors and a motion vector of the current block, a sign of the difference value, Or the like.

Wherein the step of acquiring a motion vector of the current block includes the steps of: determining whether a magnitude of the difference value corresponds to a preset condition; and if the predetermined condition is satisfied, And determining the sign of the difference value based on the motion vector of the motion vector.

Here, the preset condition may be set based on an interval between adjacent vectors among the two or more candidate motion vectors.

The step of determining whether the magnitude of the differential value corresponds to a predetermined condition may include calculating a value having a largest interval between adjacent vectors and a minimum interval between the adjacent vectors, And comparing the minimum value with the magnitude of the difference value.

Here, the predetermined condition may be set based on an interval obtained by dividing the interval between the adjacent vectors by half.

The obtaining of the motion vector of the current block may include obtaining the difference value using the magnitude of the difference value and the sign of the difference value, calculating a difference value between the first and second motion vectors of the two or more candidate motion vectors, Determining an estimated motion vector of the current block by adding a candidate motion vector, determining whether the estimated motion vector has a coordinate value closest to the first candidate motion vector among the two or more candidate motion vectors, And determining, based on the motion vector, the optimal motion vector.

Here, the step of determining the estimated motion vector and the step of determining may be repeatedly performed by substituting the remaining candidate motion vectors, excluding the first candidate motion vector, into the first candidate motion vector.

The determining of the optimal motion vector may determine the candidate motion vector as the optimal motion vector if the candidate motion vector having the closest coordinate value as a result of the iteration is unique.

Wherein the step of acquiring a motion vector of the current block includes the steps of: determining whether a magnitude of the differential value corresponds to a predetermined condition; and determining whether a motion vector of at least one of the two or more candidate motion vectors From the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

When the image decoding method and apparatus using the inter picture prediction according to the present invention as described above, the number of bits consumed in the encoding and decoding processes can be reduced.

Accordingly, there is an advantage that the image compression ratio can be improved.

1 is a conceptual diagram of an image encoding and decoding system according to an embodiment of the present invention.
2 is a block diagram of an image encoding apparatus according to an embodiment of the present invention.
3 is a block diagram of an image decoding apparatus according to an embodiment of the present invention.
4 is a diagram illustrating a method of determining a candidate motion vector for setting a motion vector of a current block in an inter-view prediction according to an embodiment of the present invention.
5 is a diagram illustrating an area where a motion vector of a current block may exist when two candidate motion vectors are present.
6 is a first example of a region where a motion vector of a current block may exist when there are three candidate motion vectors.
FIG. 7 is a second exemplary diagram illustrating an area where a motion vector of a current block may exist when there are three candidate motion vectors.
8 is a flowchart illustrating an image decoding method using inter-picture prediction according to an embodiment of the present invention.
9 is a block diagram of an image decoding apparatus using inter-picture prediction 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, A, B, etc. may be used to describe various elements, but the elements 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 in this application is used only to describe a specific embodiment and is not intended to limit 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.

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 to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Generally, an image may be composed of a series of still images. The still images may be divided into GOP (Group of Pictures) units, and each still image may be referred to as a picture. At this time, the picture may indicate one of a progressive signal, a frame in the interlace signal, and a field. When the encoding / decoding is performed on a frame-by-frame basis, If it is performed in units, it can be expressed as 'field'. In the present invention, it is assumed that a progressive signal is assumed, but it may be applicable to an interlace signal. As a higher concept, a unit such as a GOP and a sequence may exist, and each picture may be divided into predetermined areas such as slices, tiles, blocks, and the like. In addition, a unit of an I picture, a P picture, a B picture, and the like may be included in one GOP. The I picture may be a picture to be encoded / decoded by itself without using a reference picture, and the P picture and the B picture may be subjected to a process such as motion estimation (Motion estimation) and motion compensation (motion compensation) And may be a picture to be encoded / decoded. In general, an I picture and a P picture can be used as a reference picture in the case of a P picture, and a reference picture can be used as an I picture and a P picture in the case of a B picture, but this definition can also be changed by setting of encoding / decoding .

Here, a picture referred to in encoding / decoding is referred to as a reference picture, and a block or pixel to be referred to is referred to as a reference block and a reference pixel. The reference data may be not only the pixel values of the spatial domain but also the coefficient values of the frequency domain and various encoding / decoding information generated and determined during the encoding / decoding process. For example, in the prediction unit, intra prediction information or motion related information, conversion related information in the conversion unit / inverse transform unit, quantization related information in the quantization unit / dequantization unit, and encoding / decoding related information Context information), and filter-related information in the in-loop filter unit.

The minimum unit for forming an image may be a pixel, and the number of bits used to represent one pixel is called a bit depth. In general, the bit depth may be 8 bits and may support more bit depths depending on the encoding settings. The bit depth may be supported by at least one bit depth depending on the color space. Also, it may be configured as at least one color space according to the color format of the image. One or more pictures having a predetermined size or one or more pictures having different sizes according to a color format. For example, in the case of YCbCr 4: 2: 0, it may be composed of one luminance component (Y in this example) and two chrominance components (Cb / Cr in this example) The composition ratio may have a width of 1: 2. As another example, in the case of 4: 4: 4, it may have the same composition ratio in the horizontal and vertical directions. If it is composed of more than one color space as in the above example, the picture can perform the division into each color space.

In the present invention, some color spaces (Y in this example) of some color formats (YCbCr in this example) will be described, and the same color space (Cb, Cr in this example) Similar applications (settings dependent on a specific color space) can be made. However, it may also be possible to place a partial difference (an independent setting for a specific color space) in each color space. That is, the setting depending on each color space has a setting proportional to or dependent on the composition ratio of each component (for example, determined by 4: 2: 0, 4: 2: 2, 4: 4: 4, And the setting independent of each color space can be regarded as having a setting of only the corresponding color space regardless of the constituent ratio of each element or independently. In the present invention, depending on the subdecoder, the subdecoder may have an independent setting for some of the configurations or may have a dependent setting.

Syntax elements required in the image coding process can be defined at a unit level such as video, sequence, picture, slice, tile, block, and the like, and it may be a VPS (Video Parameter Set), SPS (Sequence Parameter Set) A picture parameter set (PPS), a slice header, a tile header, a block header, or the like, and transmitted to a decoder. The decoder parses the setting information in units of the same level, And can be used in the image decoding process. In addition, related information can be transmitted and parsed in the form of SEI (Supplement Enhancement Information) or Metadata in a bit stream. Each parameter set has a unique ID value, and in the lower parameter set, it can have an ID value of an upper parameter set to be referred to. For example, information of an upper parameter set having a matching ID value among one or more higher parameter sets in the lower parameter set may be referred to. In the case where any one of the examples of various units mentioned above includes one or more other units, the corresponding unit may be referred to as an upper unit and the included unit may be referred to as a lower unit.

In the case of the setting information generated in the unit, the setting information may include contents of independent setting for each unit, or contents related to setting depending on the previous, the next, or the upper unit. Here, it can be understood that the dependent setting indicates the setting information of the corresponding unit with flag information (for example, 1 if the flag is 1, not followed by 0) to follow the setting of the previous unit and then the higher unit. The setting information in the present invention will be described with reference to an example of an independent setting, but an example in which addition or substitution is made to the contents of a relation that relies on setting information of a previous unit, a subsequent unit, or a higher unit of the current unit .

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of an image encoding and decoding system according to an embodiment of the present invention.

1, the image encoding apparatus 105 and the decoding apparatus 100 may be implemented as a personal computer (PC), a notebook computer, a personal digital assistant (PDA), a portable multimedia player (PMP) Player, a PlayStation Portable (PSP), a wireless communication terminal, a smart phone, a TV, a server terminal such as an application server and a service server, A communication device such as a communication modem for performing communication with a wired / wireless communication network, a memory (memories 120 and 125) for storing various programs for inter or intra prediction for encoding or decoding an image and memories (memories 120 and 125) And a processor (processor, 110, 115) for controlling the processor. The video encoded by the video encoding apparatus 105 can be transmitted through a wired or wireless communication network such as the Internet, a short-range wireless communication network, a wireless network, a WiBro network, or a mobile communication network in real time or non- And then transmitted to the image decoding apparatus 100 through various communication interfaces such as a serial bus (USB: Universal Serial Bus), etc., decoded by the image decoding apparatus 100, and restored and reproduced as an image. In addition, the image encoded by the image encoding apparatus 105 as a bit stream can be transferred from the image encoding apparatus 105 to the image decoding apparatus 100 via a computer-readable recording medium.

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

2, the image encoding apparatus 20 according to the present embodiment includes a predictor 200, a subtractor 205, a transformer 210, a quantizer 215, an inverse quantizer 220, An inverse transform unit 225, an adder 230, a filter unit 235, a decoded picture buffer 240, and an entropy encoding unit 245.

The prediction unit 200 may include an intra prediction unit for performing intra prediction and an inter prediction unit for performing inter prediction. Intra prediction can generate a prediction block by performing spatial prediction using pixels of adjacent blocks of the current block. In inter-prediction, motion compensation is performed by searching an area that is most matched with the current block from the reference image A prediction block can be generated. (Intra prediction) mode, a motion vector, a motion vector, and the like) for the corresponding unit (coding unit or prediction unit) Video, etc.). At this time, the processing unit to be predicted, the prediction method, and the processing unit in which the concrete contents are determined can be determined according to the subdecryption setting. For example, the prediction method, the prediction mode, and the like are determined as a prediction unit, and the prediction can be performed in units of conversion.

Subtraction unit 205 subtracts the prediction block from the current block to generate a residual block. That is, the subtractor 205 calculates the difference between the pixel value of each pixel of the current block to be encoded and the predicted pixel value of each pixel of the predictive block generated through the predictor to generate a residual block, which is a residual signal of a block form .

The transform unit 210 transforms the residual block into a frequency domain and transforms each pixel value of the residual block into a frequency coefficient. Here, the transforming unit 210 transforms the transformed transformed transformed data into transformed transformed transform coefficients based on Hadamard Transform, DCT Based Transform, DST Based Transform, and KLT Based Transform Transform) can be transformed into a frequency domain by using various transformation techniques for transforming an image signal of a spatial axis into a frequency domain. The residual signal transformed into the frequency domain is a frequency coefficient. The transform can be transformed by a one-dimensional transform matrix. Each transformation matrix can be adaptively used in horizontal and vertical units. For example, in the case of intra prediction, if the prediction mode is horizontal, a DCT-based transformation matrix may be used in the vertical direction and a DST-based transformation matrix may be used in the horizontal direction. In the case of vertical, a DCT-based transformation matrix may be used in the horizontal direction and a DST-based transformation matrix may be used in the vertical direction.

The quantization unit 215 quantizes the residual block having the frequency coefficients converted into the frequency domain by the transform unit 210. Here, the quantization unit 215 may quantize the transformed residual block using Dead Zone Uniform Threshold Quantization, a Quantization Weighted Matrix, or an improved quantization technique. It can be set to one or more quantization schemes as candidates and can be determined by encoding mode, prediction mode information, and the like.

The entropy encoding unit 245 scans the generated quantization frequency coefficient sequence according to various scanning methods to generate a quantization coefficient sequence, and outputs the quantization coefficient sequence using an entropy encoding technique or the like. The scan pattern can be set to one of various patterns such as zigzag, diagonal, and raster.

The inverse quantization unit 220 inversely quantizes the residual block quantized by the quantization unit 215. That is, the quantization unit 220 dequantizes the quantized frequency coefficient sequence to generate a residual block having a frequency coefficient.

The inverse transform unit 225 inversely transforms the inversely quantized residual block by the inverse quantization unit 220. That is, the inverse transform unit 225 inversely transforms the frequency coefficients of the inversely quantized residual block to generate a residual block having a pixel value, that is, a reconstructed residual block. Here, the inverse transform unit 225 may perform the inverse transform using the inverse transform used in the transform unit 210.

The adder 230 restores the current block by adding the predicted block predicted by the predictor 200 and the residual block reconstructed by the inverse transform unit 225. [ The restored current block is stored in the decoded picture buffer 240 as a reference picture (or a reference block), and can be used as a reference picture when coding a next block or another block or another picture in the current block.

The filter unit 235 may include one or more post-processing filter processes such as a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF). The deblocking filter can remove block distortion occurring at the boundary between the blocks in the reconstructed picture. The ALF can perform filtering based on a comparison between the reconstructed image and the original image after the block is filtered through the deblocking filter. SAO restores the offset difference from the original image on a pixel-by-pixel basis with respect to the residual block to which the deblocking filter is applied, and can be applied in the form of a band offset and an edge offset. Such a post-processing filter may be applied to the restored picture or block.

The decoded picture buffer 240 may store a restored block or picture through the filter unit 235. [ The restored block or picture stored in the decoded picture buffer 240 may be provided to the predictor 200 that performs intra-picture prediction or inter-picture prediction.

Although not shown in the figure, a division unit may be further included, and the division unit may be divided into coding units of various sizes. At this time, the encoding unit may be composed of a plurality of encoding blocks (for example, one luminance encoding block, two color difference encoding blocks, etc.) according to the color format. For ease of explanation, one color component unit is assumed. The encoding block may have variable sizes such as MxM (e.g., M is 4, 8, 16, 32, 64, 128, etc.). Alternatively, according to a division scheme (for example, a tree-based division, a quad tree division, a binary tree division, or the like), an encoding block is M × N (for example, M and N are 4, 8, 16, 32, 64, 128, etc.). At this time, the encoded block may be a unit that is a basis for intra-picture prediction, inter-picture prediction, conversion, quantization, entropy coding, and the like. In the present invention, although it is described under the assumption that a plurality of sub-blocks having the same size and shape are obtained according to the division method, asymmetric sub-blocks (for example, 4M x 4N for 3M x 4N and M x 4N or 4M x 3N and 4M x N, etc.). At this time, the asymmetric sub-block can be supported by the information for determining whether or not the sub-block is additionally supported according to the sub-decoding setting in the dividing scheme for obtaining symmetric sub-blocks.

The division of an encoding block (MxN) may have a recursive tree-based structure. At this time, whether or not division is possible can be indicated by a division flag (for example, a quadtree division flag and a binary division flag). For example, when the division flag of the coding block having the division depth k is 0, the coding block is encoded in the coding block having the division depth k. If the division flag of the coding block having the division depth k is 1 The encoding of the encoding block is performed in four sub-encoding blocks (quad tree segmentation) or two sub-encoding blocks (binary tree segmentation) with a division depth of k + 1 according to the division method. In this case, the size of the block is (M >> 1) × (N >> 1) in the case of four encoding blocks and (M >> 1) × N or M × (N >> 1) Lt; / RTI &gt; The sub-encoding block is set as a coding block (k + 1) and divided into sub-coding blocks (k + 2) through the above process. At this time, one partition flag (e.g., partitioning flag) may be supported in the case of a quadtree partition, and at least one (at most two) flags in the case of a binary tree partition (for example, Split direction flags <horizontally or vertically, depending on the preceding or previous splitting result, may be omitted in some cases) may be supported.

The block division starts from the maximum encoding block and can proceed to the minimum encoding block. Alternatively, it may proceed from the minimum splitting depth to the maximum splitting depth. That is, the partitioning can be performed recursively until the block size reaches the minimum coding block size or the division depth reaches the maximum division depth. At this time, in accordance with the sub / decoding setting (for example, image <slice, tile> type <I / P / B>, coding mode <Intra / Inter>, color difference component <Y / Cb / Cr> The size of the minimum coding block, and the maximum division depth can be adaptively set. For example, when the maximum coded block is 128 × 128, the quadtree partitioning can be performed in the range of 8 × 8 to 128 × 128, the binary tree partitioning can be performed in the range of 4 × 4 to 32 × 32, . &Lt; / RTI &gt; Alternatively, the quadtree partitioning may be performed in the range of 8 x 8 to 128 x 128, and the binary tree partitioning may be performed in the range of 4 x 4 to 128 x 128 and the maximum division depth of 3. In the former case, it may be an I picture type (for example, a slice), and in the latter case, a P or B picture type. As described in the above example, the division setting such as the size of the maximum coding block, the size of the minimum coding block, and the maximum division depth can be shared or individually supported according to the division method.

If a plurality of partitioning schemes are supported, the partitioning is performed within the block support range of each partitioning scheme, and if the block support ranges of each partitioning scheme overlap, the priority of the partitioning scheme may exist. For example, a quadtree partition may precede a binary tree partition. Also, if a plurality of division methods are supported, it may be determined whether or not to perform a following division according to the result of the preceding division. For example, if the result of the preceding division indicates that the division is performed, the sub-coding block divided according to the preceding division can be set as the coding block again to perform the division without performing the following division.

Alternatively, if the result of the preceding segmentation indicates that the segmentation is not performed, the segmentation may be performed according to the result of the succeeding segmentation. In this case, when the result of the succeeding division indicates that the division is performed, the divided sub-coded blocks may be set as a coding block again to perform division, and if the result of the following division indicates that division is not performed, . At this time, when the succeeding division result indicates that the division is performed and the divided sub-coded blocks are set as the encoding block again, when a plurality of division methods are supported, only the following division . That is, when a plurality of division methods are supported, if the result of the preceding division shows that the division is not performed, it means that the preceding division is no longer performed.

For example, the M × N encoded block can confirm the quad tree division flag when quad tree division and binary tree division are possible, and when the division flag is 1 (M >> 1) x (N >> 1) The sub-encoding block is divided into four sub-encoding blocks of size, and the sub-encoding block is set as the encoding block again to perform the segmentation (quad-tree segmentation or binary tree segmentation). If the division flag is 0, the binary tree division flag can be confirmed. If the flag is 1, the sub-encoding block is divided into two sub-coded blocks of size (M >> 1) × N or M × (N >> 1) Is performed and the sub-encoding block is set as an encoding block again to perform segmentation (binary tree segmentation). If the division flag is 0, the dividing process is terminated and the coding process proceeds.

Although a case where a plurality of division methods are performed through the above example has been described, the present invention is not limited thereto, and various combinations of supporting methods can be possible. For example, a partitioning scheme such as quadtree / binary tree / quadtree + binary tree can be used. In this case, the basic partitioning method can be set to a quad tree method, the additional partitioning method can be set to a binary tree method, and information on whether or not the additional partitioning method is supported can be explicitly included in a unit of a sequence, a picture, a slice, and a tile .

In the above example, the information related to the division such as the size information of the encoding block, the support range of the encoding block, the maximum division depth, and the like may be included in the unit of the sequence, picture, slice, tile or the like or implicitly determined. In summary, the range of allowable blocks can be determined by the size of the maximum coded block, the range of supported blocks, the maximum division depth, and the like.

The coding block obtained by performing the division through the above process can be set to the maximum size of intra-picture prediction or inter-picture prediction. That is, the coded block after the block division may be the start size of the division of the prediction block for intra-picture prediction or inter-picture prediction. For example, if the coding block is 2M x 2N, the prediction block may have a size of 2M x 2N, M x N that is equal to or smaller than the prediction block. Alternatively, it may have a size of 2Mx2N, 2MxN, Mx2N, and MxN. Alternatively, it may have the same size as the encoding block and have a size of 2M x 2N. In this case, the fact that the encoding block and the prediction block have the same size may mean that the prediction is performed with the size acquired through the division of the encoding block without performing the division of the prediction block. That is, the partition information for the prediction block is not generated. Such a setting may be applied to a transform block, and the transform may be performed on a divided block basis. That is, the square block or the rectangular block obtained according to the division result may be a block used for intra prediction or inter prediction, or may be a block used for transformation and quantization of residual components.

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

3, the image decoding apparatus 30 includes an encoding picture buffer 300, an entropy decoding unit 305, a predicting unit 310, an inverse quantization unit 315, an inverse transform unit 320, 325, a filter 330, and a decoded picture buffer 335.

In addition, the prediction unit 310 may include an intra prediction module and an inter prediction module.

First, when an image bitstream transmitted from the image encoding apparatus 20 is received, the image bitstream can be stored in the encoding picture buffer 300.

The entropy decoding unit 305 may decode the bitstream to generate quantized coefficients, motion vectors, and other syntax. The generated data may be transmitted to the predicting unit 310.

The prediction unit 310 may generate a prediction block based on the data transmitted from the entropy decoding unit 305. [ At this time, based on the reference image stored in the decoded picture buffer 335, a reference picture list using a default construction technique may be constructed.

The inverse quantization unit 315 is provided as a bitstream and can dequantize the quantized transform coefficients decoded by the entropy decoding unit 305. [

The inverse transform unit 320 may apply inverse DCT, inverse integer transform, or similar inverse transformation techniques to the transform coefficients to generate residual blocks.

The inverse quantization unit 315 and the inverse transformation unit 320 inversely perform the processes performed by the transform unit 210 and the quantization unit 215 of the image encoding apparatus 20 described above and may be implemented in various ways have. For example, the same process and inverse transformation that are shared with the transform unit 210 and the quantization unit 215 may be used, and information on the transform and quantization process (for example, transform size, transform Shape, quantization type, etc.), the transformation and quantization processes can be performed inversely.

The residual block subjected to the inverse quantization and inverse transform process may be added to the prediction block derived by the prediction unit 310 to generate a reconstructed image block. This addition may be performed by the adder / subtracter 325.

The filter 330 may apply a deblocking filter to the reconstructed image block to remove a blocking phenomenon if necessary, and may further add other loop filters to improve the video quality before and after the decoding process. It can also be used.

The reconstructed and filtered image block may be stored in the decoded picture buffer 335.

4 is a diagram illustrating a method of determining a candidate motion vector for setting a motion vector of a current block in an inter-view prediction according to an embodiment of the present invention.

When a block similar to the current block is found in a block within a frame temporally different from the frame to which the current block belongs, a motion vector can be used as information indicating the corresponding block in order to generate a prediction block of the current block. At this time, if the coordinate value of the motion vector to be encoded is large, the bit loss rate may be very large. Therefore, after selecting an optimal motion vector from candidate motion vectors that are expected to be highly similar to a motion vector to be encoded, the encoding apparatus selects information indicating an optimal motion vector, a difference between a motion vector to be encoded and an optimal motion vector Value and difference value to the decoding apparatus. In this case, the optimal motion vector may be a motion vector having a minimum distance from the motion vector of the current block among the candidate motion vectors so that the difference value may be minimized.

Here, how to determine a candidate motion vector is a problem. Referring to FIG. 4, a motion vector of a neighboring block adjacent to the current block can be determined as a candidate motion vector. That is, since the motion vectors of the neighboring blocks A, B, C, D, and E adjacent to the current block are likely to be similar to the motion vectors of the current block, Can be determined as a vector.

In addition to the neighboring block adjacent to the current block, a block (or a picture) in the same position as the current block in a frame (or picture) temporally adjacent and coded with respect to the frame (or picture) The motion vector may be determined as a candidate motion vector.

In addition, the candidate motion vector may be selected from two or more blocks in the same block as the current block in a neighboring block or temporally adjacent and coded frames. At this time, the number of candidate motion vectors and the selection condition of the candidate motion vector may be preset in the encoding apparatus and the decoding apparatus.

Hereinafter, the information indicating the optimal motion vector, the difference value between the motion vector of the current block and the optimal motion vector, the information indicating the optimal motion vector among the codes for the difference value, A description will be made of a case where information is known and a method of not coding information for indicating an optimal motion vector or a code for a difference value will be described.

5 is a diagram illustrating an area where a motion vector of a current block may exist when two candidate motion vectors are present.

Referring to FIG. 5, it is possible to explain a case in which the decoding apparatus can know the information indicating the optimal motion vector or the sign of the difference value when there are two candidate motion vectors. Also, a and b may be x or y coordinate values for a candidate motion vector, but they are hereinafter simply referred to as candidate motion vectors.

First, when an optimal motion vector is selected from two candidate motion vectors a and b and a difference value (mvd, moving vector difference) between an optimal motion vector and a motion vector k of the current block is coded, Let the difference value (mvd) between the vector and the motion vector (k) of the current block have a relationship as shown in the following Equation (1).

(인접한 후보 움직임 벡터들 a, b 사이의 거리의 반에 해당) 보다 더 먼 거리에 위치할 수 있다. 즉, 현재 블록의 움직임 벡터(k)는 도 5에서 제1 영역(51a)와 제2 영역(52a)에 위치할 수 있다. 이때, 현재 블록의 움직임 벡터(k)가 제2 영역(52a)에 위치하면 후보 움직임 벡터 a보다 후보 움직임 벡터 b와 더 가까워지게 된다. 현재 블록의 움직임 벡터(k)가 후보 움직임 벡터 a보다 후보 움직임 벡터 b와 가까우면, 최적의 움직임 벡터가 a라는 전제조건에 어긋나므로, 현재 블록의 움직임 벡터(k)는 제2 영역(52a)에는 위치할 수 없고, 제1 영역(51a)에 위치할 수 있다.In the relation of Equation (1), if the candidate motion vector a is an optimal motion vector, the motion vector (k) of the current block is based on the candidate motion vector a

(Corresponding to half the distance between adjacent candidate motion vectors a, b). That is, the motion vector k of the current block may be located in the first area 51a and the second area 52a in FIG. At this time, if the motion vector k of the current block is located in the second region 52a, the motion vector k is closer to the candidate motion vector b than the candidate motion vector a. If the motion vector k of the current block is closer to the candidate motion vector b than to the candidate motion vector a, the motion vector k of the current block is in the second region 52a, And can be located in the first region 51a.

보다 더 먼 거리에 위치할 수 있다. 즉, 현재 블록의 움직임 벡터(k)는 도 5에서 제3 영역(51b)와 제4 영역(52b)에 위치할 수 있다. 이때, 현재 블록의 움직임 벡터(k)가 제3 영역(51b)에 위치하면 후보 움직임 벡터 b보다 후보 움직임 벡터 a와 더 가까워지게 된다. 현재 블록의 움직임 벡터(k)가 후보 움직임 벡터 b보다 후보 움직임 벡터 a와 가까우면, 최적의 움직임 벡터가 b라는 전제조건에 어긋나므로, 현재 블록의 움직임 벡터(k)는 제3 영역(51b)에는 위치할 수 없고, 제4 영역(52b)에 위치할 수 있다.When the candidate motion vector b is an optimal motion vector in the relation of Equation (1), the motion vector k of the current block is calculated based on the candidate motion vector b

It can be located farther than the above. That is, the motion vector k of the current block may be located in the third region 51b and the fourth region 52b in FIG. At this time, if the motion vector k of the current block is located in the third region 51b, the motion vector k is closer to the candidate motion vector a than the candidate motion vector b. If the motion vector k of the current block is closer to the candidate motion vector a than the candidate motion vector b, the motion vector k of the current block deviates from the third region 51b, And can be located in the fourth region 52b.

In summary, it can be seen that when the equation (1) is satisfied, the motion vector k of the current block is located in the first area 51a or the fourth area 52b. Information can be omitted or the sign for the difference value between the optimal motion vector and the motion vector of the current block can be omitted.

Specifically, a method of omitting the sign for the difference value between the optimal motion vector and the motion vector of the current block is as follows.

First, when a is an optimal motion vector, the motion vector k of the current block is located in the first area 51a. Therefore, if the optimal motion vector is a, the motion vector k of the current block is located on the left side of a (a value smaller than a), so that the motion vector k of the current block and the optimal motion vector It can be seen that the difference value ka with a) is always negative in the precondition.

Next, when b is an optimal motion vector, the motion vector k of the current block is located in the fourth region 52b. Therefore, if the optimal motion vector is b, the motion vector k of the current block is located to the right of b (a position having a value larger than b), so that the motion vector k of the current block and the optimal motion vector It can be seen that the difference value (kb) with b) is always positive in the preconditioning condition.

If the equation (1) is satisfied, the encoding apparatus skips the process of transmitting the optimal motion vector and the sign of the difference value to the motion vector of the current block to the decoding apparatus, and calculates the difference value and the optimal motion vector And can transmit the instructed information to the decryption apparatus. If the optimal motion vector is a as a result of referring to the information indicating the optimal motion vector, the decoding apparatus determines that the motion vector (k) of the current block is located in the first area 51a And can determine that the sign of the difference value is negative. If the optimal motion vector is b as a result of referring to the information indicating the optimal motion vector, the decoding apparatus determines whether the motion vector k of the current block is located in the fourth region 52b It can be determined that the sign of the difference value is positive.

On the other hand, a method of omitting information indicating an optimal motion vector is as follows.

If the encoding apparatus omits the information indicating the optimal motion vector and transmits the size and the sign of the difference value between the optimal motion vector and the motion vector of the current block to the decoding apparatus, It is possible to add the candidate motion vector a that can be the optimal motion vector to the identified difference value. The derived value (which can be an estimated value of the motion vector coordinate value for the current block, which can be referred to as an estimated motion vector). If a and b have a value close to a, the optimal motion vector is determined to be a can do. If a is an optimal motion vector, the value obtained by adding the candidate motion vector a to the difference value ka becomes the motion vector k of the current block, and the encoder determines that the candidate motion vector a is the motion vector of the current block (k), the optimal motion vector is selected.

In the same manner, the decoding apparatus can confirm the difference value through the magnitude and sign of the difference value, and add the candidate motion vector b that can be an optimal motion vector to the identified difference value. If the derived value has a value close to b among a and b, it can be determined that the optimal motion vector is b.

As a result of performing the above processes on all candidate motion vectors, several motion vectors that can be optimal motion vectors may be derived. In this case, since the decoding apparatus can not select any optimal motion vector, the encoding apparatus can not omit the information indicating the optimal motion vector. That is, there may be a case where one optimal motion vector is not selected from the candidate motion vectors. In this case, the above method is not applied.

Herein, the method of omitting the information indicating the optimal motion vector has been described based on the case where there are two candidate motion vectors, but it is easy for the ordinary technician to apply the same method even when there are a plurality of candidate motion vectors And therefore no further explanation is given.

6 is a first example of a region where a motion vector of a current block may exist when there are three candidate motion vectors. FIG. 7 is a second exemplary diagram illustrating an area where a motion vector of a current block may exist when there are three candidate motion vectors.

6 and 7, when there are three candidate motion vectors a, b, and c (represented by x or y coordinates in the drawing), the interval between the candidate motion vectors (x, y, The intervals between candidate motion vectors) may be between a and b, and between b and c.

In this case, a large interval between the candidate motion vectors may be defined as DL, and a small interval may be defined as DS. If the interval between the candidate motion vectors a and b is large and the interval between the candidate motion vectors b and c is small as shown in FIGS. 6 and 7, DL and DS are calculated by the following equations (2) and Respectively.

The relationship between the difference value between the motion vector of the current block and the optimal motion vector in the relation of Equations (2) and (3) satisfies the following Equation (4).

In the condition of Equation (4), a region in which the motion vector of the current block is located is shown in FIG.

Referring to FIG. 6, when the candidate motion vector a is an optimal motion vector, the motion vector k of the current block is located within a distance that is larger than DS and less than or equal to DL on the basis of a, And may be located in the second region 62a. That is, in this case, the difference value (k-a) may be both positive and negative.

In addition, when the candidate motion vector b is an optimal motion vector, the motion vector k of the current block is located within a distance greater than DS and smaller than or equal to DL on the basis of b, have. If the motion vector k of the current block is greater than b and the motion vector k of the current block is larger than the DS based on b in the case where the candidate motion vector b is the optimal motion vector, The candidate motion vector b is more approximate to the candidate motion vector c than the vector b. Therefore, when the candidate motion vector b is the optimal motion vector, the motion vector k of the current block can not be greater than b, so that the difference value k-b is negative.

 In addition, when the candidate motion vector c is an optimal motion vector, the motion vector k of the current block may be located in the fourth region 62c because the motion vector k is located within a distance greater than DS and less than or equal to DL with respect to c . In this case, if the motion vector k of the current block is smaller than c and smaller than the value of DS based on c in the case where the candidate motion vector c is the optimal motion vector, the motion vector k of the current block is a candidate motion The candidate motion vector c is closer to the candidate motion vector b than the vector c, so that the candidate motion vector c may deviate from the precondition that the motion vector is an optimal motion vector. Therefore, when the candidate motion vector c is an optimal motion vector, the motion vector k of the current block can not be smaller than c, so that the difference value k-c is positive.

6, when the optimal motion vector is a, the motion vector k of the current block is located in the first area 61a and the second area 62a, The difference value ka between the motion vector a of the current block and the motion vector k of the current block becomes negative and becomes positive in the second region 62a so that the difference value ka can have both positive and negative numbers . Therefore, when the optimal motion vector is a, the decoding apparatus can not know the sign of the difference value, so that the encoding apparatus can transmit information indicating the sign, magnitude, and optimal motion vector of the difference value (k-a) to the decoding apparatus.

However, if the optimal motion vector is b, since the motion vector k of the current block is located in the third region 61b, the decoding apparatus can know that the sign of the difference value (k-b) is negative. If the optimal motion vector is c, the motion vector k of the current block is located in the fourth region 62c, so that the decoding apparatus can know that the sign of the difference value (k-c) is positive. Therefore, when the optimal motion vector is b or c, the coding apparatus can omit transferring the sign of the difference value to the decoding apparatus.

Assume that the relationship between the difference between the motion vector of the current block and the optimal motion vector satisfies the following equation (5) in the above Equations (2) and (3).

7 shows the area where the motion vector k of the current block is located under the condition of Equation (5).

Referring to FIG. 7, when the candidate motion vector a is an optimal motion vector, the motion vector k of the current block is located within a distance greater than DL with respect to a, and thus may be located in the first region 71a . In this case, if the motion vector k of the current block is greater than a and is located at a distance greater than DL with respect to a when the candidate motion vector a is an optimal motion vector, the motion vector k of the current block is a candidate motion The candidate motion vector a becomes closer to the candidate motion vector b than the vector a, and thus the candidate motion vector a may deviate from the precondition that the motion vector is an optimal motion vector. Therefore, when the candidate motion vector a is an optimal motion vector, the motion vector k of the current block can not be larger than a, so that the difference value k-a may be negative.

In addition, when the candidate motion vector b is an optimal motion vector, the motion vector k of the current block should be located at a distance greater than DL with respect to b. In this case, if the candidate motion vector b is an optimal motion vector and the motion vector k of the current block is located at a distance greater than DL with respect to b, the motion vector k of the current block is a candidate Is closer to the motion vector a or c, the candidate motion vector b may deviate from the precondition that the motion vector is an optimal motion vector. Therefore, if the candidate motion vector is b, there is no region in which the motion vector k of the current block exists, so the candidate motion vector can not be b.

In addition, when the candidate motion vector c is an optimal motion vector, the motion vector k of the current block is located in the second region 72c since it is located within a distance larger than DL with respect to c. In this case, if the motion vector k of the current block is smaller than c and is located at a distance greater than DL with respect to c in the case where the candidate motion vector c is an optimal motion vector, the motion vector k of the current block is a candidate motion vector c, the candidate motion vector c may deviate from the precondition that the motion vector is an optimal motion vector. Therefore, when the candidate motion vector c is an optimal motion vector, the motion vector k of the current block can not be smaller than c, so that the difference value k-c can always be positive.

Assuming Equation (5) as a precondition, the description of FIG. 7 is as follows. When the optimal motion vector is a, the motion vector k of the current block is located in the first region 71a, The decryption apparatus can know that the difference value ka between the optimal motion vector a and the motion vector k of the current block is negative. Therefore, when the optimal motion vector is a, the encoding apparatus can omit transferring the sign of the difference value to the decoding apparatus.

Also, when the optimal motion vector is b, the motion vector k of the current block does not exist. Therefore, when the equation (5) is satisfied, the optimal motion vector can not be b. Therefore, the coder decides a or c as a candidate motion vector except for b in the candidate motion vector, And the decoding apparatus can determine whether the equation (5) is satisfied, and analyze a or c as an optimal motion vector through the information indicating the optimal motion vector. In this case, since one candidate motion vector is excluded, a bit value (1 bit) smaller than a bit value (2 bits) indicating one of the three motion vectors can be used, thereby increasing the efficiency of encoding and decoding.

When the optimal motion vector is c, the motion vector k of the current block is located in the second region 72c, and the optimal motion vector c and the motion vector k of the current block in the second region 72c, It is possible for the encoding apparatus to omit transferring the sign of the difference value to the decoding apparatus when the optimal motion vector is c.

8 is a flowchart illustrating an image decoding method using inter-picture prediction according to an embodiment of the present invention.

Referring to FIG. 8, a method of decoding an image using inter-picture prediction includes receiving a bitstream (S100), obtaining a part of information indicating a motion vector of a current block to be decoded in the received bitstream (S110) (S120) of obtaining a motion vector of the current block by determining information other than the partial information using the obtained information, and generating a predictive block of the current block through inter-picture prediction using the motion vector of the current block (S130). &Lt; / RTI &gt;

Here, the information indicating the motion vector of the current block may include at least one of a magnitude of a difference value between a best motion vector selected from two or more candidate motion vectors and a motion vector of the current block, a sign of the difference value, Or the like.

Here, the step of obtaining the motion vector of the current block (S120) may include the steps of: determining whether the magnitude of the difference value corresponds to a preset condition; and if the predetermined condition is satisfied, And determining the sign of the difference value based on the obtained optimal motion vector.

Here, the preset condition may be set based on an interval between adjacent vectors among the two or more candidate motion vectors.

The step of determining whether the magnitude of the differential value corresponds to a predetermined condition may include calculating a value having a largest interval between adjacent vectors and a minimum interval between the adjacent vectors, And comparing the minimum value with the magnitude of the difference value.

Here, the predetermined condition may be set based on an interval obtained by dividing the interval between the adjacent vectors by half.

Here, the step of acquiring the motion vector of the current block (S120) may include acquiring the difference value using the magnitude of the difference value and the sign of the difference value, calculating the difference value using the two or more candidate motion vectors Determining an estimated motion vector of the current block by adding a first candidate motion vector of the first candidate motion vector to the first candidate motion vector to determine whether the estimated motion vector has a coordinate value closest to the first candidate motion vector among the two or more candidate motion vectors; And determining the optimal motion vector based on the determination result.

Here, the step of determining the estimated motion vector and the step of determining may be repeatedly performed by substituting the remaining candidate motion vectors, excluding the first candidate motion vector, into the first candidate motion vector.

The determining of the optimal motion vector may determine the candidate motion vector as the optimal motion vector if the candidate motion vector having the closest coordinate value as a result of the iteration is unique.

Here, the step of acquiring the motion vector of the current block (S120) may include: determining whether a magnitude of the differential value corresponds to a preset condition; and if the predetermined condition is satisfied, acquiring a motion vector of at least one of the two or more candidate motion vectors The motion vector of the candidate motion vector may be excluded from the candidate motion vector and the optimal motion vector may be determined from among the remaining candidate motion vectors.

9 is a block diagram of an image decoding apparatus using inter-picture prediction according to an embodiment of the present invention.

9, an apparatus 200 for decoding an image using inter-picture prediction includes at least one processor 210 and instructions for instructing the at least one processor 210 to perform at least one step (Memory) 220 for storing the data.

Here, the image decoding apparatus 200 may further include a communication module 230 for receiving a bit stream from the image encoding apparatus through a wired / wireless network.

Here, the video decoding apparatus 200 may further include a local storage 240 for storing reference pictures, decoded blocks, and the like necessary for the video decoding process.

Wherein the at least one step comprises the steps of: receiving a bitstream; obtaining a part of information indicating a motion vector of a current block to be decoded in the received bitstream; Obtaining a motion vector of the current block by determining a motion vector of the current block, and generating a prediction block of the current block through inter-picture prediction using the motion vector of the current block.

Here, the information indicating the motion vector of the current block may include at least one of a magnitude of a difference value between a best motion vector selected from two or more candidate motion vectors and a motion vector of the current block, a sign of the difference value, Or the like.

Wherein the step of acquiring a motion vector of the current block includes the steps of: determining whether a magnitude of the difference value corresponds to a preset condition; and if the predetermined condition is satisfied, And determining the sign of the difference value based on the motion vector of the motion vector.

Here, the preset condition may be set based on an interval between adjacent vectors among the two or more candidate motion vectors.

The step of determining whether the magnitude of the differential value corresponds to a predetermined condition may include calculating a value having a largest interval between adjacent vectors and a minimum interval between the adjacent vectors, And comparing the minimum value with the magnitude of the difference value.

Here, the predetermined condition may be set based on an interval obtained by dividing the interval between the adjacent vectors by half.

The obtaining of the motion vector of the current block may include obtaining the difference value using the magnitude of the difference value and the sign of the difference value, calculating a difference value between the first and second motion vectors of the two or more candidate motion vectors, Determining an estimated motion vector of the current block by adding a candidate motion vector, determining whether the estimated motion vector has a coordinate value closest to the first candidate motion vector among the two or more candidate motion vectors, And determining, based on the motion vector, the optimal motion vector.

Here, the step of determining the estimated motion vector and the step of determining may be repeatedly performed by substituting the remaining candidate motion vectors, excluding the first candidate motion vector, into the first candidate motion vector.

The determining of the optimal motion vector may determine the candidate motion vector as the optimal motion vector if the candidate motion vector having the closest coordinate value as a result of the iteration is unique.

Wherein the step of acquiring a motion vector of the current block includes the steps of: determining whether a magnitude of the differential value corresponds to a predetermined condition; and determining whether a motion vector of at least one of the two or more candidate motion vectors From the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

Here, the image decoding apparatus 200 may be, for example, a desktop computer, a laptop computer, a notebook, a smart phone, a tablet PC, a mobile phone mobile phone, smart watch, smart glass, e-book reader, portable multimedia player (PMP), portable game machine, navigation device, digital camera, digital multimedia a digital audio recorder, a digital audio player, a digital video recorder, a digital video player, a PDA (Personal Digital Assistant), and the like.

The methods according to the present invention can be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer readable medium may be those specially designed and constructed for the present invention or may be available to those skilled in the computer software.

Examples of computer-readable media include hardware devices that are specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may include machine language code such as those produced by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

Also, the above-described method or apparatus may be implemented by combining all or a part of the configuration or function, or may be implemented separately.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

Claims (20)

As an image decoding method using inter picture prediction,
Receiving a bitstream;
Obtaining a part of information indicating a motion vector of a current block to be decoded in the received bitstream;
Acquiring a motion vector of the current block by determining information other than the part using the acquired information; And
And generating a prediction block of the current block through inter-picture prediction using the motion vector of the current block. In claim 1,
Wherein the information indicating the motion vector of the current block includes:
A motion vector of the current block, a difference value between a motion vector of the current block and a motion vector of the current block, information indicating a sign of the difference value, and information indicating the optimal motion vector, among the two or more candidate motion vectors, Way. In claim 2,
Wherein the step of obtaining the motion vector of the current block comprises:
Determining whether a magnitude of the differential value corresponds to a preset condition; And
And determining a sign of the difference value based on an optimal motion vector obtained from information indicating the optimal motion vector, when the predetermined condition is satisfied. In claim 3,
The predetermined condition is that,
Wherein the motion vector is set based on an interval between adjacent vectors among the two or more candidate motion vectors. In claim 4,
Wherein the step of determining whether the magnitude of the difference value corresponds to a predetermined condition includes:
Deriving a value having the largest interval between the adjacent vectors and a value having the smallest interval between the adjacent vectors; And
And comparing the largest value and the smallest value with a magnitude of the difference value. In claim 4,
The predetermined condition is that,
And the interval between the adjacent vectors is divided by half. In claim 2,
Wherein the step of obtaining the motion vector of the current block comprises:
Obtaining the difference value using the magnitude of the difference value and the sign of the difference value;
Determining an estimated motion vector of the current block by adding a first candidate motion vector of the two or more candidate motion vectors to the obtained difference value;
Determining whether the estimated motion vector has a coordinate value closest to the first candidate motion vector among the two or more candidate motion vectors; And
And determining the optimal motion vector based on the determination result. In claim 7,
Wherein the step of determining the estimated motion vector comprises:
And substituting the remaining candidate motion vectors excluding the first candidate motion vector for the first candidate motion vector. In claim 8,
Wherein determining the optimal motion vector comprises:
Wherein if the candidate motion vector having the closest coordinate value as a result of the iterative process is unique, the candidate motion vector is determined as the optimal motion vector. In claim 2,
Wherein the step of obtaining the motion vector of the current block comprises:
Determining whether a magnitude of the differential value corresponds to a preset condition; And
And determining the optimal motion vector among the remaining candidate motion vectors by excluding at least one motion vector of the two or more candidate motion vectors from the candidate motion vectors if the predetermined condition is met. . An image decoding apparatus using inter picture prediction,
At least one processor; And
A memory for storing instructions that direct the at least one processor to perform at least one step,
Wherein the at least one step comprises:
Receiving a bitstream;
Obtaining a part of information indicating a motion vector of a current block to be decoded in the received bitstream;
Acquiring a motion vector of the current block by determining information other than the part using the acquired information; And
And generating a prediction block of the current block through inter-picture prediction using the motion vector of the current block. In claim 11,
Wherein the information indicating the motion vector of the current block includes:
A motion vector of the current block, a difference value between a motion vector of the current block and a motion vector of the current block, information indicating a sign of the difference value, and information indicating the optimal motion vector, among the two or more candidate motion vectors, Device. In claim 12,
Wherein the step of obtaining the motion vector of the current block comprises:
Determining whether a magnitude of the differential value corresponds to a preset condition; And
And determining a sign of the difference value based on an optimal motion vector obtained from information indicating the optimal motion vector, when the predetermined condition is satisfied. In claim 13,
The predetermined condition is that,
Wherein the motion vector is set based on an interval between adjacent vectors among the two or more candidate motion vectors. In claim 14,
Wherein the step of determining whether the magnitude of the difference value corresponds to a predetermined condition includes:
Deriving a value having the largest interval between the adjacent vectors and a value having the smallest interval between the adjacent vectors; And
And comparing the largest value and the smallest value with a magnitude of the difference value. In claim 14,
The predetermined condition is that,
And an interval obtained by dividing the interval between the adjacent vectors by half. In claim 12,
Wherein the step of obtaining the motion vector of the current block comprises:
Obtaining the difference value using the magnitude of the difference value and the sign of the difference value;
Determining an estimated motion vector of the current block by adding a first candidate motion vector of the two or more candidate motion vectors to the obtained difference value;
Determining whether the estimated motion vector has a coordinate value closest to the first candidate motion vector among the two or more candidate motion vectors; And
And determining the optimal motion vector based on the determination result. In claim 17,
Wherein the step of determining the estimated motion vector comprises:
And the candidate motion vectors excluding the first candidate motion vector are substituted into the first candidate motion vector. In claim 18,
Wherein determining the optimal motion vector comprises:
And determines the candidate motion vector as the optimal motion vector if the candidate motion vector having the closest coordinate value as the result of the iteration is unique. In claim 12,
Wherein the step of obtaining the motion vector of the current block comprises:
Determining whether a magnitude of the differential value corresponds to a preset condition; And
And determining the optimal motion vector among the remaining candidate motion vectors by excluding at least one motion vector of the two or more candidate motion vectors from the candidate motion vector if the predetermined condition is met. .

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