KR102586198B1 - Image decoding method and apparatus using inter picture prediction - Google Patents

Abstract

A video decoding method and device using inter-screen prediction are disclosed. An image decoding method using inter-screen prediction includes the steps of receiving a bitstream, acquiring part of the information indicating the motion vector of the current block to be decoded from the received bitstream, and excluding the part by using the obtained information. It includes obtaining a motion vector of the current block by determining remaining information, and generating a prediction block of the current block through inter-screen prediction using the motion vector of the current block. Therefore, the efficiency of video encoding and decoding can be improved.

Description

Image decoding method and device using inter-picture prediction {IMAGE DECODING METHOD AND APPARATUS USING INTER PICTURE PREDICTION}

The present invention relates to an image decoding method and device using inter-screen prediction, and more specifically, to the size, sign, and optimal motion of the difference value of the motion vector in encoding and decoding the motion vector required for inter-screen prediction of the current block. This relates to a technology that reduces the number of data or bits exchanged between an encoding device and a decoding device by using only part of the information indicating a vector to determine the remaining information.

The respective organizations, called the ISO/ISE MPEG (Moving Picture Experts Group) and the ITU-T VCEG (Video Coding Experts Group), formed the Joint Collaborative Team on Video Coding (JCV-VC) and established the ISO/IEC MPEG-H in January 2013. HEVC (High Efficiency Video Coding)/ITU-T H.265 video compression standard technology has been established. In addition, in order to respond to the trend of popularization of high-definition video due to the rapid development of information and communication technology, ISO/ISE MPEG and ITU-T VCEG organized the Joint Video Exploration Team (JVET) at the 22nd JCT-VC Geneva meeting. Therefore, we are actively working to establish a next-generation video compression technology standard for video compression of UHD (Ultra High Definition) quality, which is clearer than HD (High Definition) quality.

Meanwhile, according to the existing video compression standard technology, the amount of encoded data is reduced by generating a prediction block for the current block to be encoded and encoding the difference between the prediction block and the current block. This prediction technology involves reducing the amount of encoded data within the same screen. An intra-screen prediction method that generates a prediction block for the current block using similarity with spatially adjacent blocks, and an inter-screen prediction method that generates a prediction block for the current block using similarity with blocks in temporally adjacent screens. There is.

At this time, inter-screen prediction uses a motion vector as information indicating blocks with similarity within screens temporally adjacent to the current block. At this time, since the bit value can be very large when the motion vector is encoded as is, the encoding device constructs candidate motion vectors using the motion vectors of the current block and adjacent neighboring blocks, and selects the optimal motion vector from among the candidate motion vectors. The difference value between and the motion vector of the current block is encoded and transmitted to the decoding device.

However, even when encoding the difference value between the optimal motion vector and the motion vector of the current block, if the optimal motion vector is very different from the motion vector of the current block, the bit value consumption reduction effect is minimal. Therefore, in order to improve the efficiency of video encoding and decoding, there is a need for a method to reduce the amount of information transmitted between the encoding device and the decoding device.

The purpose of the present invention to solve the above problems is to provide a video decoding method using inter-screen prediction.

Another purpose of the present invention to solve the above problems is to provide a video decoding device using inter-screen prediction.

One aspect of the present invention to achieve the above object provides a video decoding method using inter-screen prediction.

Here, the video decoding method using inter-screen prediction includes the steps of receiving a bitstream, acquiring part of the information indicating the motion vector of the current block to be decoded from the received bitstream, and using the obtained information to decode the part. It may include obtaining a motion vector of the current block by determining the remaining information, and generating a prediction block of the current block through inter-screen prediction using the motion vector of the current block.

Here, the information indicating the motion vector of the current block includes the size of the difference value between the motion vector of the current block and the optimal motion vector selected from two or more candidate motion vectors, the sign of the difference value, and the optimal motion vector. It may include at least one of the information indicating.

Here, the step of acquiring the motion vector of the current block includes determining whether the size of the difference value corresponds to a preset condition, and if it corresponds to the preset condition, the optimal motion vector obtained from the information indicating the optimal motion vector. It may include determining the sign of the difference value based on the motion vector.

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

Here, the step of determining whether the size of the difference value corresponds to a preset condition includes deriving the largest value of the gap between the adjacent vectors and the smallest value of the gap between the adjacent vectors, and the largest value. and comparing the smallest value with the size of the difference value.

Here, the preset condition may be set based on an interval divided by half the interval between adjacent vectors.

Here, the step of acquiring the motion vector of the current block includes obtaining the difference value using the size of the difference value and the sign of the difference value, and adding the first of the two or more candidate motion vectors to the obtained difference value. Determining an estimated motion vector of the current block by adding candidate motion vectors; 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 a result. As a basis, it may include determining the optimal motion vector.

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

Here, in the step of determining the optimal motion vector, if the candidate motion vector with the closest coordinate value is unique as a result of the repeated performance, the candidate motion vector may be determined as the optimal motion vector.

Here, the step of obtaining the motion vector of the current block includes determining whether the size of the difference value corresponds to a preset condition, and if the size of the difference value corresponds to the preset condition, at least one motion vector among the two or more candidate motion vectors. It may include excluding from the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

Another aspect of the present invention for achieving the above object provides a video decoding device using inter-screen prediction.

Here, the image decoding device using inter-screen prediction may include at least one processor and a memory that stores instructions that instruct the at least one processor to perform at least one step. there is.

Here, the at least one step includes receiving a bitstream, obtaining part of the information indicating the motion vector of the current block to be decoded from the received bitstream, and using the obtained information to obtain the remaining information except for the part. It may include obtaining a motion vector of the current block by determining , and generating a prediction block of the current block through inter-screen prediction using the motion vector of the current block.

Here, the information indicating the motion vector of the current block includes the size of the difference value between the motion vector of the current block and the optimal motion vector selected from two or more candidate motion vectors, the sign of the difference value, and the optimal motion vector. It may include at least one of the information indicating.

Here, the step of acquiring the motion vector of the current block includes determining whether the size of the difference value corresponds to a preset condition, and if it corresponds to the preset condition, the optimal motion vector obtained from the information indicating the optimal motion vector. It may include determining the sign of the difference value based on the motion vector.

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

Here, the step of determining whether the size of the difference value corresponds to a preset condition includes deriving the largest value of the gap between the adjacent vectors and the smallest value of the gap between the adjacent vectors, and the largest value. and comparing the smallest value with the size of the difference value.

Here, the preset condition may be set based on an interval divided by half the interval between adjacent vectors.

Here, the step of acquiring the motion vector of the current block includes obtaining the difference value using the size of the difference value and the sign of the difference value, and adding the first of the two or more candidate motion vectors to the obtained difference value. Determining an estimated motion vector of the current block by adding candidate motion vectors; 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 a result. As a basis, it may include determining the optimal motion vector.

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

Here, in the step of determining the optimal motion vector, if the candidate motion vector with the closest coordinate value is unique as a result of the repeated performance, the candidate motion vector may be determined as the optimal motion vector.

Here, the step of obtaining the motion vector of the current block includes determining whether the size of the difference value corresponds to a preset condition, and if the size of the difference value corresponds to the preset condition, at least one motion vector among the two or more candidate motion vectors. It may include excluding from the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

When using the video decoding method and device using inter-screen prediction according to the present invention as described above, the number of bits consumed in the encoding and decoding process can be reduced.

Therefore, there is an advantage that the image compression rate can be improved.

1 is a conceptual diagram of an image encoding and decoding system according to an embodiment of the present invention.
Figure 2 is a block diagram of a video encoding device according to an embodiment of the present invention.
Figure 3 is a configuration diagram of a video decoding device according to an embodiment of the present invention.
Figure 4 is an example diagram of a method for determining a candidate motion vector for setting a motion vector of a current block in inter-screen prediction according to an embodiment of the present invention.
Figure 5 is an example diagram showing an area where the motion vector of the current block can exist when there are two candidate motion vectors.
Figure 6 is a first example diagram showing an area where the motion vector of the current block can exist when there are three candidate motion vectors.
Figure 7 is a second example diagram showing an area where the motion vector of the current block can exist when there are three candidate motion vectors.
Figure 8 is a flowchart of a video decoding method using inter-screen prediction according to an embodiment of the present invention.
Figure 9 is a configuration diagram of a video decoding device using inter-screen prediction according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. While describing each drawing, similar reference numerals are used for similar components.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention. The term and/or includes any of a plurality of related stated items or a combination of a plurality of related stated items.

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

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Typically, an image may be composed of a series of still images, and these 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 represent one of a progressive signal, a frame in an interlace signal, or a field, and when encoding/decoding is performed on a frame basis, the image is a 'frame' or a field. When performed as a unit, it can be expressed as a ‘field’. Although the present invention is described assuming a progressive signal, it may also be applied to an interlace signal. As a higher-level concept, units such as GOP and sequence may exist, and each picture may be divided into predetermined areas such as slices, tiles, and blocks. Additionally, one GOP may include units such as I pictures, P pictures, and B pictures. An I picture may refer to a picture that is encoded/decoded on its own without using a reference picture, and P pictures and B pictures use a reference picture to perform processes such as motion estimation and motion compensation. It may refer to a picture that is encoded/decoded. Generally, in the case of P pictures, I pictures and P pictures can be used as reference pictures, and in the case of B pictures, I pictures and P pictures can be used as reference pictures, but this may also change the above definition depending on the encoding/decoding settings. You can.

Here, the picture referenced for encoding/decoding is called a reference picture, and the referenced block or pixel is called a reference block or reference pixel. In addition, reference data may be not only pixel values in the spatial domain, but also coefficient values in the frequency domain, and various encoding/decoding information generated and determined during the encoding/decoding process. For example, in-screen prediction-related information or motion-related information in the prediction unit, transformation-related information in the transform/inverse transform unit, quantization-related information in the quantization/inverse quantization unit, and encoding/decoding-related information in the encoder/decoder ( context information), and in the in-loop filter unit, filter-related information, etc. may be applicable.

The smallest unit that makes up an image may be a pixel, and the number of bits used to express one pixel is called bit depth. Generally, the bit depth can be 8 bits, and depending on the encoding settings, higher bit depths can be supported. At least one bit depth may be supported depending on the color space. Additionally, it may be composed of at least one color space depending on the color format of the image. Depending on the color format, it may consist of one or more pictures with a certain size or one or more pictures with a different size. 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), and in this case, the chrominance component and the luminance component The composition ratio can be 1:2 horizontally and vertically. As another example, in the case of 4:4:4, the horizontal and vertical ratios can be the same. When composed of more than one color space as in the above example, the picture can be divided into each color space.

In the present invention, the description will be based on some color spaces (Y in this example) of some color formats (YCbCr in this example), and the same is true for other color spaces (Cb, Cr in this example) according to the color format. A similar application (setting dependent on a specific color space) can be made. However, it may also be possible to have partial differences in each color space (settings that are independent of the specific color space). In other words, the settings dependent on each color space are proportional to or dependent on the composition ratio of each component (e.g., 4:2:0, 4:2:2, 4:4:4, etc.). This may mean that settings independent of each color space may mean having settings only for the corresponding color space regardless of or independently of the composition ratio of each component. In the present invention, depending on the encoder/decoder, some configurations may have independent settings or dependent settings.

Setting information or syntax elements required in the video encoding process can be determined at the unit level of video, sequence, picture, slice, tile, and block, and include VPS (Video Parameter Set), SPS (Sequence Parameter Set), It can be included in the bitstream in units such as PPS (Picture Parameter Set), Slice Header, Tile Header, Block Header, etc. and transmitted to the decoder. The decoder parses the units at the same level and transmits the setting information from the encoder. can be restored and used in the video decoding process. Additionally, related information in the form of SEI (Supplement Enhancement Information) or metadata can be transmitted as a bitstream, parsed, and used. Each parameter set has a unique ID value, and a lower parameter set can have the ID value of the upper parameter set to be referenced. For example, a lower parameter set may refer to information of a higher parameter set with a matching ID value among one or more higher parameter sets. Among the various examples of units mentioned above, when one unit includes one or more other units, the corresponding unit may be referred to as a higher-level unit, and the included unit may be referred to as a lower-level unit.

In the case of setting information generated in the unit, it may include information about independent settings for each unit, or it may include information about settings dependent on the previous, subsequent, or higher unit. Here, the dependent setting can be understood as indicating the setting information of the unit as flag information that follows the settings of the previous, next, and upper unit (for example, a 1-bit flag, followed if 1, not followed if 0). The setting information in the present invention will be explained focusing on examples of independent settings, but there will also be examples of additions or replacements to content about relationships dependent on the setting information of units before and after the current unit or upper units. may be included.

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

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

Referring to FIG. 1, the video encoding device 105 and the decoding device 100 are used in a personal computer (PC), a laptop computer, a personal digital assistant (PDA), and a portable multimedia player (PMP). It can be a user terminal such as a player, PlayStation Portable (PSP), wireless communication terminal, smart phone, TV, etc., or a server terminal such as an application server and service server, and various devices or Communication devices such as communication modems for communicating with wired and wireless communication networks, memory (120, 125) for storing various programs and data for inter or intra prediction for encoding or decoding images, and calculation by executing the program and a variety of devices including processors 110 and 115 for control. In addition, the video encoded into a bitstream by the video encoding device 105 is transmitted in real time or non-real time through a wired or wireless network such as the Internet, a short-range wireless communication network, a wireless LAN network, a WiBro network, or a mobile communication network, or a cable or general purpose network. It can be transmitted to the video decoding device 100 through various communication interfaces such as a serial bus (USB: Universal Serial Bus), decoded by the video decoding device 100, restored to an image, and played back. Additionally, an image encoded into a bitstream by the image encoding device 105 may be transmitted from the image encoding device 105 to the image decoding device 100 through a computer-readable recording medium.

Figure 2 is a block diagram of a video encoding device according to an embodiment of the present invention.

As shown in FIG. 2, the image encoding device 20 according to this embodiment includes a prediction unit 200, a subtraction unit 205, a transform unit 210, a quantization unit 215, and an inverse quantization unit 220. , may include 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-screen prediction unit that performs intra-screen prediction and an inter-screen prediction unit that performs inter-screen prediction. Intra-screen prediction can generate a prediction block by performing spatial prediction using pixels of blocks adjacent to the current block, and inter-screen prediction can perform motion compensation by finding the area that best matches the current block from the reference image. A prediction block can be created. Decide whether to use intra-prediction or inter-prediction for the corresponding unit (encoding unit or prediction unit), and specific information according to each prediction method (e.g., intra-prediction mode, motion vector, reference video, etc.) can be determined. At this time, the processing unit in which prediction is performed and the processing unit in which the prediction method and specific contents are determined may be determined according to encoding/decoding settings. For example, the prediction method, prediction mode, etc. are determined in prediction units, and prediction may be performed in transformation units.

The subtraction unit 205 generates a residual block by subtracting the prediction block from the current 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 prediction block generated through the prediction unit to generate a residual block, which is a residual signal in the form of a block. .

The conversion unit 210 converts the residual block into the frequency domain and converts each pixel value of the residual block into a frequency coefficient. Here, the transform unit 210 is a Hadamard Transform, a Discrete Cosine Transform based Transform (DCT Based Transform), a Discrete Sine Transform based Transform (DST Based Transform), and a Karunen-Rubbé Transform based Transform (KLT Based Transform). The residual signal can be converted to the frequency domain using various conversion techniques that convert the image signal in the spatial axis to the frequency axis, such as Transform), and the residual signal converted to the frequency domain becomes the frequency coefficient. The transformation can be transformed by a one-dimensional transformation matrix. Each transformation matrix can be used adaptively in horizontal and vertical units. For example, in the case of intra-screen prediction, when 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 vertical case, a DCT-based transformation matrix can be used in the horizontal direction, and a DST-based transformation matrix can be used in the vertical direction.

The quantization unit 215 quantizes the residual block having the frequency coefficient converted to the frequency domain by the conversion unit 210. Here, the quantization unit 215 may quantize the converted residual block using dead zone uniform threshold quantization, quantization weighted matrix, or an improved quantization technique. This can have one or more quantization techniques as candidates and can be determined by encoding mode, prediction mode information, etc.

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

The inverse transform unit 225 inversely transforms the residual block inversely quantized by the inverse quantization unit 220. That is, the inverse transform unit 225 inversely transforms the frequency coefficients of the inverse quantized residual block to generate a residual block with pixel values, that is, a restored residual block. Here, the inverse transformation unit 225 may perform inverse transformation by using the conversion method used in the transformation unit 210 in reverse.

The addition unit 230 restores the current block by adding the prediction block predicted by the prediction unit 200 and the residual block restored by the inverse transform unit 225. The restored current block is stored as a reference picture (or reference block) in the decoding picture buffer 240 and can be used as a reference picture when coding the next block of the current block or another block or picture in the future.

The filter unit 235 may include one or more post-processing filter processes, such as a deblocking filter, Sample Adaptive Offset (SAO), and Adaptive Loop Filter (ALF). The deblocking filter can remove block distortion occurring at the boundaries between blocks in the restored picture. ALF can perform filtering based on the value of comparing the restored image with the original image after blocks are filtered through a deblocking filter. SAO restores the offset difference from the original image on a pixel basis for the residual block to which the deblocking filter has been applied, and can be applied in the form of a band offset, edge offset, etc. This post-processing filter can be applied to the restored picture or block.

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

Although not shown in the drawing, a division unit may be further included, and the division unit may be divided into coding units of various sizes. At this time, the coding unit may be composed of a plurality of coding blocks according to the color format (for example, one luminance coding block, two chrominance coding blocks, etc.). For convenience of explanation, the explanation is made assuming one color component unit. A coding block may have a variable size such as M×M (for example, M is 4, 8, 16, 32, 64, 128, etc.). Alternatively, depending on the partitioning method (e.g., tree-based partitioning, quad tree partitioning, binary tree partitioning, etc.), the coding block may be M×N (e.g., M and N are 4, 8, 16, 32, 64, It can have variable sizes such as 128, etc.). At this time, the coding block may be a basic unit for intra-screen prediction, inter-screen prediction, transformation, quantization, entropy coding, etc. The present invention is described under the assumption that a plurality of sub-blocks with the same size and shape are obtained according to the partitioning method, but in the case of an asymmetric sub-block (for example, in the case of a binary tree, 4M × 4N is 3M × 4N and M × 4N, or Application to the case of dividing into 4M × 3N and 4M × N, etc.) may also be possible. At this time, the asymmetric sub-block can be supported by information that determines whether to support it additionally according to the encoding/decoding settings in the division method for obtaining the symmetric sub-block.

Division of the coding block (M×N) may have a recursive tree-based structure. At this time, whether to split can be indicated through a split flag (eg, quad tree split flag, binary split flag). For example, if the split flag of a coding block with a split depth of k is 0, encoding of the coding block is performed in a coding block with a split depth of k, and the split flag of the coding block with a split depth of k is 1. In this case, encoding of the coding block is performed in four sub-coding blocks (quad-tree splitting) or two sub-coding blocks (binary tree splitting) with a splitting depth of k+1, depending on the splitting method. At this time, the size of the block is (M >> 1) × (N >> 1) for 4 coding blocks, and (M >> 1) × N or M × (N >> 1) for 2 coding blocks. It can be. The sub-coding block can be set again as a coding block (k+1) and divided into a sub-coding block (k+2) through the above process. At this time, in the case of quad tree splitting, one split flag (e.g., a splitting flag) may be supported, and in the case of binary tree splitting, at least one (up to two) flags (e.g., in addition to the splitting flag) may be supported. A split direction flag <horizontal or vertical. Can be omitted in some cases depending on the preceding parent or previous split result>) may be supported.

Block division can start from the largest coding block and proceed to the minimum coding block. Alternatively, you can start from the minimum segmentation depth and proceed to the maximum segmentation depth. That is, division can be performed recursively until the size of the block reaches the minimum coding block size or the division depth reaches the maximum division depth. At this time, the maximum coding block is encoded according to the encoding/decoding settings (e.g., video <slice, tile> type <I/P/B>, encoding mode <Intra/Inter>, chrominance component <Y/Cb/Cr>, etc.) The size of , minimum coding block size, and maximum division depth can be set adaptively. For example, when the maximum coding block is 128×128, quad tree division can be performed in the range of 8×8 to 128×128, and binary tree division can be performed in the range of 4×4 to 32×32 with a maximum division depth of 3. It can be done in some cases. Alternatively, quad tree partitioning can be performed in the range of 8 × 8 to 128 × 128, and binary tree partitioning can be performed in the range of 4 × 4 to 128 × 128 with a maximum partition depth of 3. In the former case, the setting may be in the I image type (e.g., slice), and in the latter case, the setting may be in the P or B image type. As described in the above example, split settings such as the maximum coding block size, minimum coding block size, maximum split depth, etc. may be common or individually supported depending on the split method.

When multiple partitioning methods are supported, partitioning is performed within the block support range of each partitioning method, and if the block support ranges of each partitioning method overlap, the partitioning method may have priority. For example, a quad tree split may precede a binary tree split. Additionally, when multiple division methods are supported, whether to perform a subsequent division may be determined depending on the result of the preceding division. For example, if the result of the preceding division indicates that division is to be performed, the subsequent division may not be performed, and the sub-coding block divided according to the preceding division may be set again as a coding block to perform division.

Alternatively, if the result of the preceding division indicates that division is not to be performed, division may be performed according to the result of the subsequent division. At this time, if the result of the subsequent division indicates that division is to be performed, the divided sub-coding block is set again as a coding block to perform division, and if the result of the subsequent division indicates that division is not performed, further division is not possible. does not perform. At this time, when the succeeding division result indicates that division is performed and the divided sub-coding block is set again as a coding block and multiple division methods are supported, the preceding division is not performed and only the succeeding division is performed. Support is available. That is, when multiple division methods are supported and the result of the preceding division indicates that division is not performed, this means that the preceding division is no longer performed.

For example, if quad tree partitioning and binary tree partitioning are possible for an M Splitting is performed into four sub-coding blocks of the same size, and the sub-coding blocks are set again as coding blocks to perform splitting (quad tree splitting or binary tree splitting). If the split flag is 0, the binary tree split flag can be checked, and if the flag is 1, it is split into two sub-encoding blocks of size (M >> 1) × N or M × (N >> 1). After this is performed, the sub-coding block is again set as a coding block to perform splitting (binary tree splitting). If the segmentation flag is 0, the segmentation process is terminated and encoding is performed.

Although the above example has described a case in which a plurality of division methods are performed, the present invention is not limited to this and a support combination of various division methods may be possible. For example, a partitioning method such as quad tree/binary tree/quad tree + binary tree may be used. At this time, the basic partitioning method can be set to the quad tree method, the additional partitioning method can be set to the binary tree method, and information about whether the additional partitioning method is supported can be explicitly included in units such as sequence, picture, slice, and tile. .

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

The coding block obtained by performing segmentation through the above process can be set to the maximum size of intra-screen prediction or inter-screen prediction. In other words, the coding block for which block division has been completed may be the starting size of division of the prediction block for intra-screen prediction or inter-screen prediction. For example, if the coding block is 2M×2N, the prediction block may have a size of 2M×2N or M×N, which is the same or smaller than that. Alternatively, it may have a size of 2M×2N, 2M×N, M×2N, or M×N. Alternatively, it may have a size of 2M×2N, the same size as the coding block. At this time, the fact that the coding block and the prediction block have the same size may mean that prediction is performed with the size obtained through division of the coding block without performing division of the prediction block. That is, this means that segmentation information for the prediction block is not generated. These settings can also be applied to transform blocks, and transformation can be performed in units of divided coding blocks. That is, the square or rectangular block obtained according to the division result may be a block used for intra-screen prediction or inter-screen prediction, or may be a block used for transformation or quantization of the residual component.

Figure 3 is a configuration diagram of a video decoding device according to an embodiment of the present invention.

Referring to FIG. 3, the image decoding device 30 includes an encoded picture buffer 300, an entropy decoder 305, a prediction unit 310, an inverse quantization unit 315, an inverse transform unit 320, and an adder/subtractor ( 325), a filter 330, and a decoded picture buffer 335.

Additionally, the prediction unit 310 may be configured to include an intra-screen prediction module and an inter-screen prediction module.

First, when the video bitstream transmitted from the video encoding device 20 is received, it may be stored in the encoded picture buffer 300.

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

The prediction unit 310 may generate a prediction block based on data delivered 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 may be constructed using a default construction technique.

The inverse quantization unit 315 may inverse quantize the quantized transform coefficients provided as a bitstream and decoded by the entropy decoder 305.

The inverse transform unit 320 may generate a residual block by applying inverse DCT, inverse integer transform, or similar inverse transform techniques to the transform coefficients.

At this time, the inverse quantization unit 315 and the inverse transform unit 320 reversely perform the process performed by the transform unit 210 and the quantization unit 215 of the image encoding device 20 described above and can be implemented in various ways. there is. For example, the same process and inverse transformation shared with the transform unit 210 and the quantization unit 215 may be used, and information about the transform and quantization process (e.g., transform size, transform The transformation and quantization process can be reversed using shape, quantization type, etc.).

The residual block that has gone through the inverse quantization and inverse transformation process may be added to the prediction block derived by the prediction unit 310 to generate a restored image block. This addition can be performed by the adder/subtractor 325.

The filter 330 may apply a deblocking filter to the reconstructed image block to remove blocking phenomenon as needed, and may additionally add other loop filters before and after the decoding process to improve video quality. You can also use it.

The image block that has undergone restoration and filtering may be stored in the decoded picture buffer 335.

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

In order to generate a prediction block for the current block, if a block similar to the current block is found in a block in a frame temporally different from the frame to which the current block belongs, a motion vector can be used as information indicating the block. At this time, if the coordinate value of the motion vector to be encoded is large, the bit loss rate may be very high. Therefore, the encoding device selects the optimal motion vector among candidate motion vectors expected to have high similarity to the motion vector to be encoded, then provides information indicating the optimal motion vector, and the difference between the motion vector to be encoded and the optimal motion vector. The sign of the value and difference value can be transmitted to the decoding device. At this time, the optimal motion vector may be a motion vector that has the minimum distance from the motion vector for the current block among candidate motion vectors so that the difference value can be minimized.

Here, the question is how to determine the candidate motion vector. Referring to FIG. 4, the motion vector of a neighboring block adjacent to the current block can be determined as the candidate motion vector. In other words, the motion vectors of the current block (Current BLOCK) and adjacent neighboring blocks (A, B, C, D, E) are likely to be similar to the motion vector of the current block, so the candidate motion representing the motion vector of the current block It can be decided as a vector.

In addition, not only the neighboring blocks adjacent to the current block, but also the block (co-located BLOCK) located at the same location as the current block in the encoded frame (or picture) that is temporally adjacent to the frame (or picture) to which the current block belongs. A motion vector may be determined as a candidate motion vector.

Additionally, two or more candidate motion vectors may be selected from among neighboring blocks or blocks that are temporally adjacent and are located at the same location as the current block in the encoded frame. At this time, the number of candidate motion vectors and the selection conditions for the candidate motion vector may be set in advance in the encoding device and the decoding device.

Hereinafter, among the information indicating the optimal motion vector, the difference value between the motion vector of the current block and the optimal motion vector, and the code for the difference value, the information indicating the optimal motion vector or the code for the difference value is used in the decoding device. We will look at cases where this can be known, and based on this, we will explain how not to encode the information indicating the optimal motion vector or the sign for the difference value.

Figure 5 is an example diagram showing an area where the motion vector of the current block can exist when there are two candidate motion vectors.

Referring to FIG. 5, a case in which a decoding device can know information indicating the optimal motion vector or a code for a difference value when there are two candidate motion vectors can be explained. Additionally, a and b may refer to x or y coordinate values for a candidate motion vector, but hereinafter, they are simply referred to as candidate motion vectors.

First, if the optimal motion vector is selected among the two candidate motion vectors a and b and the difference value (mvd, moving vector difference) between the optimal motion vector and the current block's motion vector (k) is encoded, the optimal motion Let us assume that the difference value (mvd) between the vector and the motion vector (k) of the current block has the relationship as shown in Equation 1 below.

In the relationship of Equation 1 above, if the candidate motion vector a is the optimal motion vector, the motion vector (k) of the current block is based on the candidate motion vector a. It may be located at a greater distance than (corresponding to half the distance between adjacent candidate motion vectors a and 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. 5. At this time, if the motion vector (k) of the current block is located in the second area 52a, it becomes closer to the candidate motion vector b than to the candidate motion vector a. If the motion vector (k) of the current block is closer to the candidate motion vector b than the candidate motion vector a, the prerequisite that the optimal motion vector is a is violated, so the motion vector (k) of the current block is in the second area 52a. It cannot be located in , but can be located in the first area 51a.

In addition, in the relationship of Equation 1 above, if the candidate motion vector b is the optimal motion vector, the motion vector (k) of the current block is based on the candidate motion vector b. It can be located at a greater distance. That is, the motion vector (k) of the current block may be located in the third area 51b and the fourth area 52b in FIG. 5. At this time, if the motion vector (k) of the current block is located in the third area 51b, it becomes 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 precondition that the optimal motion vector is b is violated, so the motion vector (k) of the current block is in the third area 51b. It cannot be located in and can be located in the fourth area 52b.

In summary, if Equation 1 is satisfied, it can be seen that the motion vector (k) of the current block is located in the first area (51a) or the fourth area (52b). This fact indicates that the optimal motion vector is 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, the 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, looking at the case where a is the 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 to the left of a (a position with a value smaller than a), so the motion vector (k) of the current block and the optimal motion vector ( As a prerequisite, it can be seen that the difference value (k-a) from a) is always negative.

Next, looking at the case where b is the optimal motion vector, the motion vector (k) of the current block is located in the fourth area 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 with a value greater than b), so the motion vector (k) of the current block and the optimal motion vector ( As a prerequisite, it can be seen that the difference value (k-b) with b) is always a positive number.

In summary, when Equation 1 above is satisfied, the encoding device omits the process of transmitting the sign of the optimal motion vector and the difference value between the motion vector of the current block to the decoding device, and calculates the size of the difference value and the optimal motion vector. The indicated information can be transmitted to the decoding device. The decoding device determines whether Equation 1 is satisfied, and if the optimal motion vector is a as a result of referring to the information indicating the optimal motion vector, the motion vector (k) of the current block is located in the first area 51a. By understanding this, we can determine that the sign of the difference value is negative. In addition, the decoding device determines whether Equation 1 is satisfied, and if the optimal motion vector is b as a result of referring to information indicating the optimal motion vector, the motion vector (k) of the current block is located in the fourth area 52b. By understanding this, we can determine that the sign of the difference value is a positive number.

Meanwhile, the method of omitting information indicating the optimal motion vector is as follows.

If the encoding device omits the information indicating the optimal motion vector and transmits the size and sign of the difference between the optimal motion vector and the motion vector of the current block to the decoding device, the decoding device transmits the size and sign of the difference value Through this, the difference value can be confirmed, and a candidate motion vector a, which can be the optimal motion vector, can be added to the confirmed difference value. At this time, if the derived value (which may be an estimate of the motion vector coordinate value for the current block and may be referred to as an estimated motion vector) has a value close to a among a and b, it is determined that the optimal motion vector is a. can do. This is because, if a is the optimal motion vector, the value derived by adding the candidate motion vector a to the difference value (k-a) becomes the motion vector (k) of the current block, and the encoding device determines that the candidate motion vector a is the motion vector of the current block. This is because it would have been selected as the optimal motion vector because it is closest to (k).

In the same way, the decoding device can check the difference value through the size and sign of the difference value, and can add a candidate motion vector b, which can be the optimal motion vector, to the confirmed difference value. At this time, if the derived value is closer to b among a and b, it can be determined that the optimal motion vector is b.

Meanwhile, 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 device cannot select any one optimal motion vector, the encoding device cannot omit information indicating the optimal motion vector. That is, there may be cases where one optimal motion vector is not selected among candidate motion vectors, and in this case, the above method is not applied.

Here, the method of omitting the information indicating the optimal motion vector was previously explained based on the case where there are two candidate motion vectors, but it is easy for a person skilled in the art to apply the same method even when there are multiple candidate motion vectors. Since it can be easily understood, further detailed explanation will be omitted.

Figure 6 is a first example diagram showing an area where the motion vector of the current block can exist when there are three candidate motion vectors. Figure 7 is a second example diagram showing an area where the motion vector of the current block can exist when there are three candidate motion vectors.

Referring to Figures 6 and 7, when there are three candidate motion vectors a, b, and c (indicated based on x or y coordinates in the drawing), the interval between candidate motion vectors (adjacent based on x or y coordinates) Intervals between candidate motion vectors) may exist between a and b and between b and c.

At this time, among the intervals between candidate motion vectors, the larger interval can be defined as DL, and the smaller interval can be defined as DS. As shown in Figures 6 and 7, if the gap between candidate motion vectors a and b is large, and the gap between candidate motion vectors b and c is small, DL and DS are expressed in Equation 2 and Equation 3 below: Same as

Let us assume that in the relationship between Equation 2 and Equation 3 above, the relationship between the difference value between the motion vector of the current block and the optimal motion vector satisfies the following Equation 4.

Under the conditions of Equation 4 above, the area where the motion vector of the current block is located is shown in Figure 6.

Referring to FIG. 6, when the candidate motion vector a is the optimal motion vector, the motion vector (k) of the current block is located within a distance greater than DS and less than or equal to DL based on a, so that the first area 61a and It may be located in the second area 62a. That is, in this case, the difference value (k-a) can be either a positive or negative number.

In addition, when the candidate motion vector b is the optimal motion vector, the motion vector (k) of the current block is located within a distance greater than DS and less than or equal to DL based on b, so it can be located in the third area 61b. there is. At this time, in the case where the candidate motion vector b is the optimal motion vector, if the motion vector (k) of the current block is greater than b and has a value greater than DS based on b, the motion vector (k) of the current block is the candidate motion. Since it is closer to the candidate motion vector c than vector b, it may violate the prerequisite that the candidate motion vector b is the optimal motion vector. Therefore, if the candidate motion vector b is the optimal motion vector, the motion vector (k) of the current block cannot be greater than b, so the difference value (k-b) is negative.

In addition, when the candidate motion vector c is the optimal motion vector, the motion vector (k) of the current block is located within a distance greater than DS and less than or equal to DL based on c, so it can be located in the fourth area 62c. . At this time, in the case where the candidate motion vector c is the optimal motion vector, if the motion vector (k) of the current block is smaller than c and has a value smaller than DS based on c, the motion vector (k) of the current block is the candidate motion. Since it is closer to the candidate motion vector b than vector c, it may violate the prerequisite that the candidate motion vector c is the optimal motion vector. Therefore, if the candidate motion vector c is the optimal motion vector, the motion vector (k) of the current block cannot be smaller than c, so the difference value (k-c) is a positive number.

Summarizing the description of FIG. 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, and the optimal motion vector in the first area 61a is The difference value (k-a) between the motion vector (a) of and the motion vector (k) of the current block is negative, and in the second area 62a, it is positive, so the difference value (k-a) can have both positive and negative numbers. . Therefore, when the optimal motion vector is a, the decoding device cannot know the sign of the difference value, so the encoding device can transmit information indicating the sign and size of the difference value (k-a) and the optimal motion vector to the decoding device.

However, if the optimal motion vector is b, the motion vector (k) of the current block is located in the third area 61b, so the decoding device can know that the sign of the difference value (k-b) is negative. Additionally, if the optimal motion vector is c, the motion vector (k) of the current block is located in the fourth area 62c, so the decoding device can know that the sign of the difference value (k-c) is a positive number. Therefore, when the optimal motion vector is b or c, the encoding device can omit transmitting the sign of the difference value to the decoding device.

Meanwhile, let us again assume that in the relationship between Equation 2 and Equation 3 above, the relationship between the difference value between the motion vector of the current block and the optimal motion vector satisfies the following Equation 5.

Under the conditions of Equation 5, the area where the motion vector (k) of the current block is located is shown in Figure 7.

Referring to FIG. 7, when the candidate motion vector a is the optimal motion vector, the motion vector (k) of the current block is located within a greater distance than the DL based on a, so it can be located in the first area 71a. . At this time, in the case where the candidate motion vector a is the optimal motion vector, if the motion vector (k) of the current block is larger than a and is located at a greater distance than the DL based on a, the motion vector (k) of the current block is the candidate motion. Since it is closer to the candidate motion vector b than vector a, it may violate the prerequisite that the candidate motion vector a is the optimal motion vector. Therefore, if the candidate motion vector a is the optimal motion vector, the motion vector (k) of the current block cannot be greater than a, so the difference value (k-a) may be a negative number.

Additionally, if the candidate motion vector b is the optimal motion vector, the motion vector (k) of the current block must be located at a greater distance than the DL based on b. At this time, in the case where the candidate motion vector b is the optimal motion vector, if the motion vector (k) of the current block is located at a greater distance than the DL based on b, the motion vector (k) of the current block is greater than the candidate motion vector b. Because it gets closer to motion vector a or c, it may violate the prerequisite that candidate motion vector b is the optimal motion vector. Therefore, if the candidate motion vector is b, the candidate motion vector cannot be b because there is no area where the motion vector (k) of the current block exists.

Additionally, when the candidate motion vector c is the optimal motion vector, the motion vector (k) of the current block is located within a distance greater than DL based on c, and thus may be located in the second area 72c. At this time, in the case where the candidate motion vector c is the optimal motion vector, if the motion vector (k) of the current block is smaller than c and is farther than the DL based on c, the motion vector (k) of the current block is the candidate motion vector. Since it is closer to the candidate motion vector b than c, it may violate the prerequisite that the candidate motion vector c is the optimal motion vector. Therefore, if the candidate motion vector c is the optimal motion vector, the motion vector (k) of the current block cannot be smaller than c, so the difference value (k-c) can always be a positive number.

Summarizing the description of FIG. 7 with Equation 5 as a prerequisite, when the optimal motion vector is a, the motion vector (k) of the current block is located in the first area 71a and The decoding device can know that the difference value (k-a) between the optimal motion vector (a) and the motion vector (k) of the current block is a negative number. Therefore, when the optimal motion vector is a, the encoding device can omit transmitting the sign of the difference value to the decoding device.

Additionally, when the optimal motion vector is b, there is no region in which the motion vector (k) of the current block exists. Therefore, when Equation 5 is satisfied, the optimal motion vector cannot be b, so the encoding device excludes b from the candidate motion vectors, defines a or c as the candidate motion vector, and indicates the optimal motion vector among a and c. information can be generated and transmitted to the decoding device, and the decoding device can determine whether Equation 5 is satisfied and interpret a or c as the optimal motion vector through information indicating the optimal motion vector. In this case, since one candidate motion vector is excluded, a bit value (1 bit) smaller than the bit value (2 bits) indicating one of the three can be used, thereby increasing the efficiency of encoding and decoding.

In addition, when the optimal motion vector is c, the motion vector (k) of the current block is located in the second area 72c, and the optimal motion vector (c) and the motion vector (k) of the current block in the second area (72c) are The decoding device can know that the difference value (k-c) between is a positive number. Therefore, when the optimal motion vector is c, the encoding device can omit transmitting the sign of the difference value to the decoding device.

Figure 8 is a flowchart of a video decoding method using inter-screen prediction according to an embodiment of the present invention.

Referring to FIG. 8, the image decoding method using inter-screen prediction includes receiving a bitstream (S100) and obtaining some of the information indicating the motion vector of the current block to be decoded from the received bitstream (S110). , obtaining the motion vector of the current block by determining the remaining information excluding the part using the obtained information (S120), and predicting the prediction block of the current block through inter-screen prediction using the motion vector of the current block. It may include a generating step (S130).

Here, the information indicating the motion vector of the current block includes the size of the difference value between the motion vector of the current block and the optimal motion vector selected from two or more candidate motion vectors, the sign of the difference value, and the optimal motion vector. It may include at least one of the information indicating.

Here, the step of acquiring the motion vector of the current block (S120) includes determining whether the size of the difference value corresponds to a preset condition, and if it corresponds to the preset condition, information indicating the optimal motion vector. It may include determining the sign of the difference value based on the obtained optimal motion vector.

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

Here, the step of determining whether the size of the difference value corresponds to a preset condition includes deriving the largest value of the gap between the adjacent vectors and the smallest value of the gap between the adjacent vectors, and the largest value. and comparing the smallest value with the size of the difference value.

Here, the preset condition may be set based on an interval divided by half the interval between adjacent vectors.

Here, the step of acquiring the motion vector of the current block (S120) includes obtaining the difference value using the size of the difference value and the sign of the difference value, and adding the two or more candidate motion vectors to the obtained difference value. determining an estimated motion vector of the current block by adding a first candidate motion vector among the two or more candidate motion vectors; 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; It may include determining the optimal motion vector based on the determination result.

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

Here, in the step of determining the optimal motion vector, if the candidate motion vector with the closest coordinate value is unique as a result of the repeated performance, the candidate motion vector may be determined as the optimal motion vector.

Here, the step of acquiring the motion vector of the current block (S120) includes determining whether the size of the difference value corresponds to a preset condition, and if the size of the difference value corresponds to the preset condition, at least one of the two or more candidate motion vectors. It may include excluding the motion vector of from the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

Figure 9 is a configuration diagram of a video decoding device using inter-screen prediction according to an embodiment of the present invention.

Referring to FIG. 9, an image decoding apparatus 200 using inter-screen prediction includes at least one processor 210 and instructions instructing the at least one processor 210 to perform at least one step. ) may include a memory (220) for storing.

Here, the video decoding device 200 may further include a communication module 230 that receives a bitstream from the video encoding device through a wired or wireless network.

Here, the image decoding device 200 may further include a local storage 240 that stores reference pictures, decoded blocks, etc. required for the image decoding process.

Here, the at least one step includes receiving a bitstream, obtaining part of the information indicating the motion vector of the current block to be decoded from the received bitstream, and using the obtained information to obtain the remaining information except for the part. It may include obtaining a motion vector of the current block by determining , and generating a prediction block of the current block through inter-screen prediction using the motion vector of the current block.

Here, the information indicating the motion vector of the current block includes the size of the difference value between the motion vector of the current block and the optimal motion vector selected from two or more candidate motion vectors, the sign of the difference value, and the optimal motion vector. It may include at least one of the information indicating.

Here, the step of acquiring the motion vector of the current block includes determining whether the size of the difference value corresponds to a preset condition, and if it corresponds to the preset condition, the optimal motion vector obtained from the information indicating the optimal motion vector. It may include determining the sign of the difference value based on the motion vector.

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

Here, the step of determining whether the size of the difference value corresponds to a preset condition includes deriving the largest value of the gap between the adjacent vectors and the smallest value of the gap between the adjacent vectors, and the largest value. and comparing the smallest value with the size of the difference value.

Here, the preset condition may be set based on an interval divided by half the interval between adjacent vectors.

Here, the step of acquiring the motion vector of the current block includes obtaining the difference value using the size of the difference value and the sign of the difference value, and adding the first of the two or more candidate motion vectors to the obtained difference value. Determining an estimated motion vector of the current block by adding candidate motion vectors; 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 a result. As a basis, it may include determining the optimal motion vector.

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

Here, in the step of determining the optimal motion vector, if the candidate motion vector with the closest coordinate value is unique as a result of the repeated performance, the candidate motion vector may be determined as the optimal motion vector.

Here, the step of obtaining the motion vector of the current block includes determining whether the size of the difference value corresponds to a preset condition, and if the size of the difference value corresponds to the preset condition, at least one motion vector among the two or more candidate motion vectors. It may include excluding from the candidate motion vectors and determining the optimal motion vector among the remaining candidate motion vectors.

Here, examples of the image decoding device 200 include a communication capable desktop computer, a laptop computer, a laptop, a smart phone, a tablet PC, and a mobile phone ( mobile phone, smart watch, smart glass, e-book reader, PMP (portable multimedia player), portable game console, navigation device, digital camera, DMB (digital multimedia) broadcasting) player, digital audio recorder, digital audio player, digital video recorder, digital video player, PDA (Personal Digital Assistant), etc.

Methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. Computer-readable media may include program instructions, data files, data structures, etc., singly or in combination. Program instructions recorded on a computer-readable medium may be specially designed and constructed for the present invention or may be known and usable by those skilled in the computer software art.

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

Additionally, the above-described method or device may be implemented by combining all or part of its components or functions, or may be implemented separately.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can do it.

Claims (20)

A video decoding method using inter-screen prediction,
Receiving a bitstream;
Splitting a coding block based on splitting information included in the bitstream to determine a current block;
Obtaining an estimated motion vector of the current block based on a plurality of candidate motion vectors and motion vector indication information, wherein the motion vector indication information indicates one of the plurality of candidate motion vectors;
Obtaining the motion vector difference of the current block based on size information of the motion vector difference and sign information of the motion vector difference;
Obtaining a motion vector of the current block using the estimated motion vector and the motion vector difference; and
Generating a prediction block of the current block through inter-screen prediction using the motion vector of the current block,
Whether or not to signal the sign information is determined based on whether the size of the motion vector difference value is greater than a pre-defined threshold size,
If the size of the motion vector difference value is greater than a pre-defined threshold size, the sign information is signaled,
If the size of the motion vector difference value is less than or equal to a pre-defined threshold size, the code information is not signaled. In claim 1,
The splitting information includes a quad-tree splitting flag indicating whether to split based on quad-tree splitting, a binary tree splitting flag indicating whether to split based on binary tree splitting, or a splitting direction indicating whether to split in the vertical or horizontal direction. A video decoding method including at least one of the flags. In claim 2,
The video decoding method wherein the coding block is divided based on a partition type including at least one of the quad tree partition and the binary tree partition. In claim 3,
When the coding block has a size of 128x128, only the quad tree division is used to split the coding block. In claim 3,
The binary tree division is allowed only when block division based on the quad tree division is no longer performed. In claim 2,
The division direction flag is selectively signaled according to the division type of the upper block to which the coding block belongs,
An image decoding method, wherein the upper block represents a block having a smaller division depth than the coding block. A video encoding method using inter-screen prediction,
Encoding division information for dividing a first coding block into a plurality of second coding blocks;
Encoding a motion vector for inter-screen prediction of the current block,
Here, the current block is any one of the second coding blocks,
The step of encoding the motion vector of the current block is:
Encoding motion vector indication information indicating an estimated motion vector of the current block among a plurality of candidate motion vectors, and
Encoding size information for determining the size of the motion vector difference value of the current block and sign information for determining the sign of the motion vector difference value; and
Generating a bitstream including the segmentation information, the motion vector indication information, the size information, and the sign information,
Whether to encode the sign information is determined based on whether the size of the motion vector difference is greater than a pre-defined threshold size,
If the size of the motion vector difference value is greater than a pre-defined threshold size, the sign information is encoded,
If the size of the motion vector difference value is less than or equal to a pre-defined threshold size, the sign information is not encoded. In a computer-readable medium on which instructions for executing an image encoding method using inter-screen prediction on a computer are recorded,
The video encoding method is,
Encoding division information for dividing a first coding block into a plurality of second coding blocks;
Encoding a motion vector for inter-screen prediction of the current block,
Here, the current block is one of the second coding blocks,
The step of encoding the motion vector of the current block is:
Encoding motion vector indication information indicating an estimated motion vector of the current block among a plurality of candidate motion vectors, and
Encoding size information for determining the size of the motion vector difference value of the current block and sign information for determining the sign of the motion vector difference value; and
Generating a bitstream including the segmentation information, the motion vector indication information, the size information, and the sign information,
Whether to encode the sign information is determined based on whether the size of the motion vector difference is greater than a pre-defined threshold size,
If the size of the motion vector difference value is greater than a pre-defined threshold size, the sign information is encoded,
If the size of the motion vector difference is less than or equal to a pre-defined threshold size, the sign information is not encoded. delete delete delete delete delete delete delete delete delete delete delete delete

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