KR20070076392A - A method and apparatus for decoding/encoding a video signal - Google Patents

Abstract

A method and an apparatus for decoding and encoding a video signal are provided to minimize information to be transmitted for illumination compensation by estimating an offset value of a current block by using information of a neighbor block, and sending a difference, and perform accurate estimation by confirming whether a reference number of the current block is the same as reference numbers of the neighbor blocks. It is judged whether a reference number of a current block is the same as reference numbers of neighbor blocks(S410). On the basis of a result of the judgment, a predictor for compensating illumination of the current block is obtained(S420). An offset value of the current block is restored by using the obtained predictor(S430).

Description

A method and apparatus for decoding / encoding a video signal

1 illustrates a multi-view sequence encoding and decoding system to which the present invention is applied.

2 shows an example of a prediction structure between pictures in multi-view video coding to which the present invention is applied.

3 is a diagram for describing a process of obtaining an offset value of a current block according to an embodiment to which the present invention is applied.

4 is a flowchart illustrating a process of performing lighting compensation on a current block according to an embodiment to which the present invention is applied.

FIG. 5 is a flowchart illustrating a method of acquiring a predictor based on whether a current block and a neighboring block have the same reference number as an embodiment to which the present invention is applied.

6 is a flowchart illustrating a method of performing lighting compensation based on a prediction type of a current block according to an embodiment to which the present invention is applied.

FIG. 7 is a flowchart illustrating a method of performing lighting compensation using flag information indicating whether lighting compensation is performed on a corresponding block according to an embodiment to which the present invention is applied.

8 is a flowchart illustrating a method of predicting flag information of a current block based on whether a reference number of a current block and a neighboring block is the same as an embodiment to which the present invention is applied.

9 is a flowchart illustrating a method of performing illumination compensation when a current block is predictively coded using two or more reference blocks according to an embodiment to which the present invention is applied.

The present invention relates to a method and apparatus for decoding / encoding a video signal.

The mainstream video broadcasting image is a single view image acquired with one camera. Multi-view video, on the other hand, is a three-dimensional (3D) image processing method that geometrically corrects images taken by more than one camera and provides users with various viewpoints in various directions through spatial synthesis. It is a field. A multi-view video may provide a 3D stereoscopic image or an image of many viewpoints to a user, and has a feature that includes a larger area than an image area that can be acquired using a single camera.

Since the view sequences of the multi-view video described above are images obtained from different cameras, illumination differences may occur due to internal and external factors of the camera. For example, a camera heterogeneity, a difference in camera calibration, or a camera alignment is caused. Since such illumination differences significantly reduce the correlation between different views, thereby inhibiting effective coding, an illumination compensated coding technique is required to prevent this.

An object of the present invention is to increase the decoding efficiency of a video image by effectively utilizing the correlation between blocks or viewpoints.

An object of the present invention is to efficiently compensate for lighting differences between viewpoints in a multiview image.

An object of the present invention is to provide a method and apparatus for efficiently decoding video image data.

In order to achieve the above object, the present invention obtains a predictor for lighting compensation of the current block by using an offset value of a neighboring block adjacent to the current block, and uses the predictor to Restoring an offset value, wherein the predictor is determined according to whether a reference number of a current block and a reference number of the neighboring blocks are the same.

In addition, the present invention obtains a predictor for lighting compensation of the current block using the offset value of the neighboring block adjacent to the current block and restores the offset value of the current block using the predictor. Wherein the predictor is determined according to whether a reference number of a current block and a reference number of the neighboring blocks are the same, and the neighboring block used is determined according to a prediction type of the current block. A video signal decoding method is provided.

The present invention also provides a method of restoring an offset value of a current block representing a difference between an illumination average value of a current block and an illumination average value of a reference block, and when the current block is predictively coded using two or more reference blocks, And obtaining offset values for each reference block of the current block using the video signal decoding method.

The above objects and features of the construction will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In addition, the terms used in the present invention was selected as a general term widely used as possible now, but in some cases, the term is arbitrarily selected by the applicant, in which case the meaning is described in detail in the description of the invention, It is to be understood that the present invention is to be understood as the meaning of terms rather than the names of terms.

1 illustrates a multi-view sequence encoding and decoding system to which the present invention is applied. As shown in FIG. 1, the multiview image encoding system to which the present invention is applied includes a multiview image generator 10, a preprocessing part 20, and an encoding part 30. . In addition, the decoding system includes an extractor 40, an extractor 50, a decoding part 50, a post processing part 60, and a display part 70.

The multi-view image generator 10 includes an image obtaining apparatus (for example, cameras # 1 to #N) corresponding to the number of multi-views to acquire independent images for each viewpoint. When the multiview image data is input, the preprocessing unit 20 performs a function of increasing the correlation between the multiview image data through a preprocessing process while solving noise removal and imbalancing problems. The encoder 30 includes a motion estimator, a motion compensator, and a disparity estimator, a disparity compensator, an illumination compensator, a bit rate control, and a residual image encoder. do. The encoding unit 30 may apply a generally known method.

The lighting compensator of the encoding unit 30 to which the present invention is applied performs motion compensation adaptive to lighting changes for MVC. Efficient encoding may be performed by obtaining an average pixel value of the current block and an average pixel value of the corresponding reference block, obtaining and transmitting a difference between the two average pixel values. In this case, a difference between the average pixel value of the current block and the average pixel value of the reference block corresponding thereto is referred to as an offset value. In transmitting the offset value of the current block, it is necessary to further reduce the number of bits to be coded. For example, a predicate of an offset value of the current block may be obtained using neighboring blocks of the current block, a difference value between the offset value and the predictor may be obtained, and only the difference value may be transmitted. When the above process is performed, a picture of another view may be used as a reference picture. At this time, a view identifier indicating a view of the picture may be used.

The extractor 40 functions to extract only a bitstream corresponding to a desired view from the transmitted MVC bitstream. The extractor can view the header and optionally decode only the desired time point. In addition, view scalability may be implemented by extracting only a bitstream corresponding to a desired view using a view identifier that distinguishes a view of a picture. Since MVC must be fully compatible with H.264 / AVC, it is necessary to decode only certain views that are compatible with H.264 / AVC. In this case, a view identifier that distinguishes a view of the picture may be used to decode only compatible views. The bitstream extracted through the extractor 40 is transmitted to the decoding unit 50. The decoder 50 includes a motion compensator, an illumination compensator, a weight predictor, a deblocking filter, and the like. The decoding unit 50 receives the bitstream encoded by the above-described method, and decodes it in reverse.

The lighting compensator of the decoding unit 50 to which the present invention is applied performs motion compensation adaptive to lighting changes for MVC. Accordingly, in order to recover the current block, an offset value of the current block, which is a difference between the average pixel value of the current block and the average pixel value of the reference block corresponding thereto, must be transmitted from the encoding unit 30. In transmitting the offset value, as an example of a method for further reducing the number of bits to be coded, using the neighboring blocks of the current block, a predictor of the offset value of the current block is obtained, and the offset value and the free value are obtained. The difference with the dict was obtained and only the difference was transmitted. Accordingly, the decoding unit 50 extracts flag information and offset values of neighboring blocks of the current block, reference numbers of corresponding reference blocks of the current block and its neighboring blocks, and the like from the video signal, and uses the predictor to extract the predictor. Can be obtained. The offset value may be obtained between the offset value and the predictor, and the offset value of the current block may be restored using the difference value and the predictor. When performing the process of acquiring the predictor as described above, when a picture of another view is used as a reference picture, a view identifier indicating a view of the picture may be used.

In addition, the post-processing unit 60 performs a function of increasing the reliability and resolution of the decoded data. Finally, the display unit 70 provides the decoded data to the user in various ways depending on the function of the display, in particular, the ability to process a multi-view image. For example, it is a 2D display 71 that provides only a planar two-dimensional image, a stereo type display 73 that provides two views as a stereoscopic image, or a stereoscopic image of M views (2 <M). The display 75 may be provided.

2 shows an example of a prediction structure between pictures in multi-view video coding to which the present invention is applied.

As shown in FIG. 2, T0 to T100 on the horizontal axis represent frames according to time, and S0 to S7 on the vertical axis represent frames according to viewpoints, respectively. For example, pictures in T0 refer to images taken by different cameras in the same time zone (T0), and pictures in S0 refer to images in different time zones taken by one camera. In addition, the arrows in the drawing indicate the prediction direction and the order of each picture. For example, a P0 picture at S2 time point in the T0 time zone is a picture predicted from I0, and the P0 picture is also at S4 time point in the TO time zone. It becomes a reference picture of another P0 picture. It is also a reference picture of the B1 and B2 pictures in the T4 and T2 time zones at the time S2.

The lighting compensation to which the present invention is applied may be applied, for example, in the process of performing motion estimation or motion compensation, and the lighting compensation may be applied using a reference block at which the current block is different. The prediction structure may be applied when performed.

3 is a diagram for describing a process of obtaining an offset value of a current block according to an embodiment to which the present invention is applied.

Illumination compensation may be performed in a motion estimation process. When comparing the similarity between the current block and the candidate reference block, the lighting difference between the two blocks should be considered. New motion estimation / motion compensation is performed to compensate for the illumination difference. The new SAD can be obtained using Equation 2 below.

Here, M _c represents an average pixel value of the current block and M _r represents an average pixel value of the reference block. I _c (x, y) represents the pixel value at the (x, y) coordinate of the current block, and I _r (x + Δx, y + Δy) is the motion vector (Δx, Δy) of the reference block. Indicates a pixel value. By performing motion estimation based on the new SAD of Equation 1, an average pixel value difference between the current block and the reference block may be obtained. The obtained average pixel value difference is referred to as an offset value IC_offset.

When motion estimation with illumination compensation is performed, an offset value and a motion vector are obtained, and illumination compensation is performed using Equation 3 using the offset value and the motion vector.

Here, R (x, y) represents an error value in which illumination compensation is performed.

Offset value (IC_offset = M _c M _r ) should be transmitted to the decoding unit 50. Lighting compensation in the decoding unit 50 is performed as follows.

R '(x, y) denotes a two restored, the illumination compensation values to perform the error _{(residual), I' c (} x, y) represents the pixel value of the restored current block.

In order to recover the current block, an offset value must be transmitted to the decoding unit 50, and the offset value can be predicted from information of neighboring blocks. In order to further reduce the number of bits to code the offset value , only the difference value RIC_offset between the offset value IC_offset of the current block and the offset value IC_offset_pred of the neighboring block may be sent. This is shown in Equation 5 below.

RIC _ offset  = IC _ offset  ― IC_offset_pred

4 is a flowchart illustrating a process of performing lighting compensation on a current block according to an embodiment to which the present invention is applied.

When the lighting compensation flag of the current block is 0, lighting compensation for the current block is not performed. If the flag is 1, a process of restoring the offset value of the current block is performed. At this time, in obtaining the predictor of the current block, information of the neighboring block may be used. First, it is determined whether the reference number of the current block is the same as that of the neighboring block (S410). The predictor for lighting compensation of the current block is obtained based on the determination result (S420). The offset value of the current block is restored using the obtained predictor (S430). Here, it is necessary to examine in more detail the step of determining whether the reference number of the current block is the same as the reference number of the neighboring block and obtaining the predictor based on the determination result. This will be described with reference to FIG. 5.

FIG. 5 is a flowchart illustrating a method of acquiring a predictor based on whether a current block and a neighboring block have the same reference number as an embodiment to which the present invention is applied.

In order to perform lighting compensation, the decoding unit 50 extracts flag information and offset values of neighboring blocks of the current block, reference numbers of corresponding reference blocks of the current block and its neighboring blocks, and the like from the video signal, and uses the information. To obtain the predicate of the current block. The offset value of the current block and the predictor may be obtained, and the offset value of the current block may be restored using the obtained difference value and the predictor. In this case, in obtaining the predictor of the current block, information of the neighboring block may be used. For example, the offset value of the current block may be predicted by using the offset value of the neighboring block. Before this, whether the reference number of the current block is the same as the reference number of the neighboring block is determined. According to the check result, which neighboring block or a value to use may be determined. In addition, it is possible to check whether the flag information of the neighboring block is true, and determine whether to use the neighboring block according to the check result.

In a specific embodiment, it is determined whether a neighboring block having the same reference number as the reference number of the current block exists (S510). As a result of the determination, when only one neighboring block having the same reference number as the reference number of the current block exists, the offset value of the neighboring block having the same reference number is allocated to the predictor of the current block (S520). When two neighboring blocks having the same reference number as the reference number of the current block exist according to the determination result of step S510, an average value of offset values of two neighboring blocks having the same reference number is assigned to the predictor of the current block. (S530). In addition, when there are three neighboring blocks having the same reference number as the reference number of the current block according to the determination result of step S510, the median of the offset values of the three neighboring blocks having the same reference number is present. It is assigned to the predictor of the block (S540). In addition, when there is no neighbor block having the same reference number as the reference number of the current block according to the determination result of step S510, the predictor of the current block is allocated to "0" (S550). In the process of checking the sameness of the above reference number (S510), it may include a condition of checking whether the flag of the corresponding neighboring block is 1.

As another embodiment, it is checked whether the neighboring block has the same reference number as that of the current block, and whether the flag of the neighboring block is 1 is checked. If there is a neighboring block that satisfies both conditions, the offset value of the neighboring block can be used as a predictor. In this case, the order of checking the neighboring blocks may be in the order of left, top, top right, and top left, or in order of top, left, top right, and top left. If there are no neighboring blocks that satisfy both of the above conditions, if the flag of the three neighboring blocks of the left, upper, upper right (or upper left) is 1, the median of the offset values of the three blocks is set as a predictor. If this is also not satisfied, the predicate of the current block may be assigned to "0".

6 is a flowchart illustrating a method of performing lighting compensation based on a prediction type of a current block according to an embodiment to which the present invention is applied.

The neighboring block referred to may vary according to the prediction type of the current block. For example, when the shape of the current block and the neighboring block is the same, the current block performs prediction by using the median of the neighboring blocks. However, when the shape is different, another method is applied. For example, if a block on the left side of the current block is divided into several blocks, the block located at the top of the block is used for prediction. Or, if the block at the top of the current block is divided into several, the leftmost block among them is used for prediction. As such, the prediction value may vary depending on which neighboring block the prediction type of the current block uses. Therefore, in an embodiment of the present invention, first, the neighboring block to be referred is determined according to the prediction type of the current block (S610). It is determined whether a reference number of the determined neighboring block and a reference number of the current block are the same (S620). Here, the process of checking whether the same reference number is the same may include a condition of checking whether the flag of the corresponding neighboring block is 1. The predictor for lighting compensation of the current block is obtained based on the determination result (S630). Lighting compensation may be performed by restoring the offset value of the current block by using the obtained predictor (S640). Here, the process of performing the step S630 based on the result of the step S620 will be described with reference to a specific embodiment. Specific embodiments of this part may be applied in a manner similar to that described with reference to FIG. 5.

For example, when the prediction type of the current block performs prediction by referring to the left block of the current block, it is determined whether the reference number of the left block of the current block is the same as the reference number of the current block. As a result of the determination, when the reference numbers are the same, the offset value of the left block is allocated to the predictor of the current block. In addition, when the prediction type of the current block performs prediction by referring to the left block and the top two blocks of the current block, or the left block and the top block and the top right block of the current block, respectively. Is applied in the same manner as described above with reference to FIG. 5.

FIG. 7 is a flowchart illustrating a method of performing lighting compensation using flag information indicating whether lighting compensation is performed on a corresponding block according to an embodiment to which the present invention is applied.

In another embodiment of the present invention, when restoring the offset value of the current block, flag information IC_flag indicating whether the current block performs lighting compensation may also be used. Alternatively, the predictor may be obtained using both the method of confirming the reference number described with reference to FIG. 5 and the method of predicting flag information. First, it is determined whether a neighboring block having the same reference number as the reference number of the current block exists (S710). The predictor for lighting compensation of the current block is obtained based on the determination result. In this case, whether the flag of the neighboring block is 1 may be included as a criterion of determination (S720). In addition, the flag information of the current block is predicted based on the determination result (S730). Lighting compensation may be performed by restoring the offset value of the current block by using the obtained predictor and the predicted flag information (S740). Here, step S720 may be applied in the same manner as described with reference to FIG. 5. The step S730 will be described in detail later with reference to FIG. 8.

8 is a flowchart illustrating a method of predicting flag information of a current block based on whether a reference number of a current block and a neighboring block is the same as an embodiment to which the present invention is applied.

In an embodiment of the present invention, first, it is determined whether a neighboring block having the same reference number as the reference number of the current block exists (S810). As a result of the determination, when only one neighboring block having the same reference number as the reference number of the current block exists, the flag information of the current block is predicted from the flag information of the neighboring block having the same reference number (S820). When there are two neighboring blocks having the same reference number as the reference number of the current block according to the determination result of step S810, the information on the current block may be determined from one of flag information of two neighboring blocks having the same reference number. The flag information is predicted (S830). In addition, when there are three neighboring blocks having the same reference number as the reference number of the current block according to the determination result of step S810, the current value is determined from the median value of the flag information of the three neighboring blocks having the same reference number. The flag information of the block is predicted (S840). In addition, when there is no neighbor block having the same reference number as the reference number of the current block according to the determination result of step S810, flag information prediction of the current block is not performed (S850).

9 is a flowchart illustrating a method of performing lighting compensation when a current block is predictively coded using two reference blocks according to an embodiment to which the present invention is applied.

In performing illumination compensation, when the current block is predictively coded using two reference blocks, the decoder cannot directly know an offset value corresponding to each reference block. This is because, when the offset value of the current block is obtained, the pixel value obtained by averaging the two reference blocks is used. Therefore, in an embodiment of the present invention, an offset value corresponding to each reference block may be obtained to enable more accurate prediction. First, the offset value of the current block is restored using the predictor and the error value of the current block (S910). When the current block is predictively coded using two reference blocks, an offset value corresponding to each reference block is obtained using the offset value (S920). This is shown in Equation 6 below.

IC_Offset = - * - *

IC_Offset =-*-*

-

= IC_Offset + (

-1)*

+

*

IC_OffsetL0 =

-

= IC_Offset + (

-One)*

+

*

-

= IC_Offset +

*

+ (

-1)*

.IC_OffsetL1 =

-

= IC_Offset +

*

+ (

-One)*

.

Here, m _c represents the average pixel value of the current block, and m _{r , 1} , m _{r , 2} represent the average pixel value of the reference block, respectively. w ₁ and w ₂ represent weight coefficients in bi-predictive coding. When the illumination compensation is performed in this manner, the accurate offset value corresponding to each reference block can be obtained and used separately, thereby enabling more accurate predictive coding.

When restoring the offset value of the current block (S920), the offset value may be obtained by adding the restored offset difference value and the predictor value. At this time, a predictor for each of List 0 and List 1 may be obtained, and a combination of these may be used to obtain a predictor necessary for restoring the offset value of the current block.

As another embodiment, the present invention may be applied to a skip macroblock. In this embodiment, prediction is performed to obtain information regarding lighting compensation. The flag information indicating whether the lighting compensation is performed may use a value predicted in the neighboring block, and the offset value of the current block may use an offset value predicted in the neighboring block. For example, if the flag information is true, the offset value is added to the reference block. As a specific example, in the case of the macroblock to which the P-Skip mode is applied, the flag and the offset value of the macroblock may be obtained by predicting using the flags and the offset values of the left and upper neighboring blocks. If only one block flag is 1, the flag and offset value of the current block may be set to the flag and offset value of the block. If both blocks have the flag 1, the flag of the current block is 1, and the offset value may be set to an average value of offset values of two neighboring blocks.

As another embodiment, the present invention may be applied to a direct prediction mode (eg, Direct, B-Skip mode). In this embodiment, prediction is performed to obtain information regarding lighting compensation. Each of the predictors can be obtained by applying the various flag and offset prediction methods described above. You can set this value to the actual flag and offset value of the current block. If each block has only a pair of flag and offset information, one prediction value for each block may be obtained. In this case, when there are two reference blocks, when the reference number is checked, it is checked whether each reference number of the current block and the neighboring block is identical. In addition, when each reference block has an offset value, the predicted first flag information, the predicted first offset value, the predicted second flag information, and the predicted second offset value may be obtained. In this case, the flag information may write a predicted value in the neighboring block, and the offset values of the two reference blocks may write the predicted first offset value and the second offset value, respectively. Here, the offset value of the current block may use an average value of the offset values of each reference block.

In the case of the direct prediction mode and the skip macroblock, flag information may be encoded / decoded. That is, the offset value may or may not be added according to the flag value. In addition, an error value between the offset value and the predicted offset value may be encoded / decoded. In this case, it can be restored more accurately, and it is possible to select the optimal one in terms of RD. In addition, when the reference picture is not available in the prediction process described herein, that is, when the reference picture number is less than 1, the flag information or the predicted flag information may be false, and the offset value or the predicted offset value may be It can be set to zero.

As another embodiment, the present invention may be applied to entropy coding. Regarding the flag information, three contexts can be considered according to the flag value of the neighboring block (for example, the left block and the upper block of the current block). If the flag value is true, it is converted to 1, and if it is false, it is converted to 0. Flag information is encoded / decoded using these three contexts. For the prediction error value of the offset, the same method as in transform coefficient levels coding can be used, for example. That is, binarization may be performed to UEG0, and one context model may be applied to the first bin value and one context model may be applied to the remaining bin values of the unary prefix part. The sign bit may be encoded / decoded in a bypass mode. As another embodiment of the flag information, two contexts may be considered according to the predicted value of the flag information and may be encoded / decoded using the context.

The technique described herein may be easy to apply on a macroblock basis, but may also be applicable to smaller blocks.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features.

Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

Each viewpoint image of the multi-view video is caused by a difference in illumination due to internal and external factors of the camera. This illumination difference significantly reduces the correlation between different viewpoints, which hinders effective encoding. Therefore, in the present invention, by predicting the offset value of the current block using the information of the neighboring block and transmitting only the difference value, it is possible to minimize the information to be transmitted for lighting compensation. In addition, when predicting the offset value of the current block, it is possible to perform a more accurate prediction by checking whether the reference number of the current block and the neighboring block is the same. In addition, it is possible to minimize the information to be transmitted by predicting flag information indicating whether the current block performs lighting compensation and transmitting only the difference value, and likewise, by checking whether the reference number of the current block and the neighboring block are the same, Predictions can be made. Through the present invention as described above, efficient coding is enabled by using correlations between blocks or viewpoints.

Claims (14)

Obtaining a predictor for lighting compensation of the current block by using an offset value of a neighboring block adjacent to the current block; Restoring an offset value of the current block using the predictor, Wherein the predictor is determined according to whether a reference number of a current block and a reference number of the neighboring blocks are the same. The method of claim 1, The neighboring block used is determined according to the prediction type of the current block. The method of claim 1, wherein when acquiring the predictor, And when one neighboring block having the same reference number as the reference number of the current block exists, an offset value of the neighboring block is assigned to a predictor of the current block. The method of claim 1, wherein when acquiring the predictor, If there are two neighboring blocks having the same reference number as the reference number of the current block, the average value of the offset values of the two neighboring blocks is assigned to the predictor of the current block. . The method of claim 1, wherein when acquiring the predictor, When two neighboring blocks having the same reference number as the reference number of the current block exist, the offset value of the neighboring block having a different reference number is set to 0, and the median of the offset values of the neighboring blocks is set to 0. And a video signal decoding method assigned to the predictor of the current block. The method of claim 1, wherein when acquiring the predictor, When there are three neighboring blocks having the same reference number as the reference number of the current block, a median of offset values of the three neighboring blocks is assigned to the predictor of the current block. Video signal decoding method. The method of claim 1, wherein when acquiring the predictor, And if the neighboring block having the same reference number as the reference number of the current block does not exist, the predictor of the current block is assigned with zero. The method of claim 1, wherein the video signal decoding method comprises: Predicting flag information indicating whether a current block is applied to lighting compensation from the video signal, And reconstructing an offset value of the current block by using the predicted flag information and the predictor. The method of claim 8, wherein when acquiring the predictor, When there is one neighbor block having the same reference number as that of the current block, flag information of the current block is predicted from flag information of the neighbor block, and an offset value of the neighbor block is Video signal decoding method characterized in that it is assigned to a predictor. The method of claim 8, wherein when acquiring the predictor, When there are two neighboring blocks having the same reference number as that of the current block, flag information of the current block is predicted from flag information of any one of flag information of the two neighboring blocks, and And a mean value of offset values of four neighboring blocks is assigned to the predictor of the current block. The method of claim 8, wherein when acquiring the predictor, When there are three neighboring blocks having the same reference number as the reference number of the current block, flag information of the current block is predicted from a median among flag information of the three neighboring blocks, and And a median of offset values of four neighboring blocks is assigned to the predictor of the current block. The method of claim 8, wherein when acquiring the predictor, When the neighboring block having the same reference number as the reference number of the current block does not exist, flag information prediction of the current block is not performed, and the predicate of the current block is assigned with 0. Decoding method. Restoring an offset value of the current block indicating a difference between an illumination average value of the current block and an illumination average value of the reference block; If the current block is predictively coded using two or more reference blocks, obtaining offset values for each reference block of the current block using the offset value Video signal decoding method comprising a. The method of claim 13, Acquiring a predictor for lighting compensation of the current block by using the obtained offset values for each reference block; And recovering the offset value of the current block by using the predictor.

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