Method for eliminating blocking effect in compressed video signal

Abstract

The present invention relates to a method for eliminating a blocking effect in a compressed video signal signal. The method of the invention includes: the encoding step of eliminating a blocking effect by compensating the motion of a signal compressed in block unit to be transmitted; the decoding step of restoring the motion compensated video signal to the original video signal by reducing the prediction residual between the motion compensated video signal and the original video signal and the blocking effect; and the post-filtering step of performing post-filtering in a blocking elimination filter in order to eliminate a blocking effect and ring effect remained in the compensated signal. The equation for obtaining the original pixel is made simple by eliminating the remaining blocking effect and ring effect using a loop/post filter. In addition, normalization parameters can be stored in the look-up table and can be detected according to the difference between pixels adjacent to the original pixel and the size of quantizaiton, whereby the equation for restoring the compressed moving video signal, resulting in excessive smoothing, becomes simpler, and filtering control is made possible by a simple equation, thus making a high speed real time video signal processing possible.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

M(f(i,j))=M_L(f(i,j))+M_R(f(i,j))+M_U(f(i,j))+M_D((f(i,j))   (2)

f(i, j); original video signal

g(i, j); video signal reconfigured in decoding unit

M(f(i, j)) function of the reliability of original pixel and degree of smoothing of each pixel

(i, j); position value of pixel indicating the position of two-dimensional video

The position of the pixels is explained in FIG. 3.

FIG. 3 is a view illustrating the position of pixels of a compressed video according to the present invention. A pixel adjacent to the original video pixel f(i, j) in a left horizontal direction is denoted by f(i, j−1), a pixel adjacent thereto in a right horizontal direction is denoted by f(i, j+1), a pixel adjacent thereto in an upper vertical direction is denoted by f(1−1, j), and a pixel adjacent thereto in a lower vertical direction is denoted by f(i+1, j).

When the position of a pixel adjacent to the original pixel is designated as described above, M_L designates a function of the reliability and degree of smoothing of pixel f(1, j−1) with respect to pixel f(i, j), M_R designates a function of the reliability and degree of smoothing of pixel f(1, j+1) with respect to pixel f(i, j), and M_U designates a function of the reliability and degree of smoothing of pixel f(i−1, 1) with respect to pixel f(i, j).

The reliability and degree of smoothing of a pixel adjacent to the original pixel are expressed by the following equations.
M_L(f(i,j))=(1−α_L(f(i,j)))[g(i,j)−f(i,j)]²+α_L(f(i,j))[f(i,j)−f(i,j−1)]²   (3)
M_R(f(i,j))=(1−α_L(f(i,j)))[g(i,j)−f(i,j)]²+α_R(f(i,j))[f(i,j)−f(i,j+1)]²   (4)
M_U(f(i,j))=(1−α_L(f(i,j)))[g(i,j)−f(i,j)]²+α_U(f(i,j))[f(i,j)−f(i−1,j)]²   (5)
M_D(f(i,j))=(1−α_L(f(i,j)))[g(i,j)−f(i,j)]²+α_D(f(i,j))[f(i,j)−f(i+1,j)]²   (6)

α_L, α_R, α_U, α_D are normalized parameters that determine the ratio of the reliability and degree of smoothing of each pixel with respect to the original pixel.

The first term of the right side of M_L(f(i, j)) represents the reliability of the original pixel obtained by subtracting the original pixel f(i, j) and the compressed pixel g(i, j), and the second term of the right side thereof represents the degree of non-uniformity of the pixel in the left horizontal direction, e.g., the degree of smoothing of pixel f(i, j−1) with respect to the original pixel f(i, j) by obtaining the difference between the original pixel f(i, j) and the left side pixel f(i, j−1). α_L is a kind of normalized parameter that determines the ratio of the reliability and degree of smoothing of the compressed video with respect to the original video. As this value becomes higher, the weight on the degree of smoothing becomes higher for thereby increasing the degree of smoothing.

The first term of the right side of M_R(f(i, j) represents the reliability of the original pixel obtained by subtracting the original pixel f(i, j) and the compressed pixel g(i, j), and the second term of the right side thereof represents the degree of non-uniformity of the pixel in the right horizontal direction, e.g., the degree of smoothing of pixel f(i, j+1) with respect to the original pixel f(i, j) by obtaining the difference between the original pixel f(i, j) and the right side pixel f(i, j+1). α_R is a kind of normalized parameter that determines the ratio of the reliability and degree of smoothing of the compressed video with respect to the original video. As this value becomes higher, the weight on the degree of smoothing becomes higher for thereby increasing the degree of smoothing.

The first term of the right side of M_U(f(i, j)) represents the reliability of the original pixel obtained by subtracting the original pixel f(i, j) and the compressed pixel g(i, j), and the second term of the right side thereof represents the degree of non-uniformity of the pixel in the upper vertical direction, e.g., the degree of smoothing of pixel f(i −1, j) with respect to the original pixel f(i, j) by obtaining the difference between the original pixel f(i, j) and the upper side pixel f(i−1, j). α_U is a kind of normalization parameter that determines the ratio of the reliability and degree of smoothing of the compressed video with respect to the original video. As this value becomes higher, the weight on the degree of smoothing becomes higher for thereby increasing the degree of smoothing.

The first term of the right side of M_D(f(i, j)) represents the reliability of the original pixel obtained by subtracting the original pixel f(i, j) and the compressed pixel g(i, j), and the second term of the right side thereof represents the degree of non-uniformity of the pixel in the lower vertical direction, e.g., the degree of smoothing of pixel f(i+1, j) with respect to the original pixel f(i, j) by obtaining the difference between the original pixel f(i, j) and the lower side pixel f(i+1, j). α_D is a kind of normalized parameter that determines the ratio of the reliability and degree of smoothing of the compressed video with respect to the original video. As this value becomes higher, the weight on the degree of smoothing becomes higher for thereby increasing the degree of smoothing.

According to the above-described equation, the restored pixel f(i, j) can be obtained according to the compressed video reconfigured in the decoding unit, the normalization parameters, the constant value of the parameter for differently setting the degree of smoothing based on the position of a pixel, and the size of quantization of the pixel encoded to an intra macroblock by the normalization restoration method.

The above described original video signal f(i, j) can be expressed by the following equations.
f(i,j)=[(4−α_TOTg(i,j)+α_L(f(i, j))g(i, j−1)+α_R(f(i,j))g(i, j+1)+α_U(f(i, j))g(i−1, j)+α_Df(i, j))g(i+1, j)]/4   (7)
α_TOT(f(i, j))−α_L(f(i, j))+α_R(f(i,j))+α_U(f(i, j))+α_Df(i, j))   (8)
α_L(f(i, j)=[K_LQP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_LQP²(f, (i, j))]  (9)
α_R(f(i,j)=[K_RQP²(f(i, j))]/[[g(i, j)−g(i, j+1)]²+K_RQP²(f(i, j))]  (10)
α_U(f(i, j)=[K_UQP²(f(i, j))]/[[g(i, j)−g(i−1, j)]²+K_UQP²(f(i, j))]  (11)
α_D(f(i, j)=[K_DQP²(f(i, j))]/[[g(i, j)−g(i+1, j)]²+K_DQP²(f(i, j))]  (12)

α_L, α_R, α_U, α_D are normalized parameters that determine the ratio of the reliability and degree of smoothing of each pixel with respect to the original pixel.

α_TOT; sum of parameters for each pixel

K; constant value of normalization parameter α for each pixel

QP(f(i, j)) size of quantization of pixel encoded to intra macroblock.

QP(f(i, j))=[676]/[A(f(i, j))],

α_L is a normalization parameter that determines the degree of smoothing of a pixel in the left direction from the pixel of the compressed video positioned at (i, j), α_R is a normalization parameter that determines the degree of smoothing of a pixel in the right direction from the pixel of the compressed video positioned at (i, j), α_U is a normalization parameter that determines the degree of smoothing of a pixel in the upper direction from the pixel of the compressed video positioned at (i, j), and α_D is a normalization parameter that determines the degree of smoothing of a pixel in the downward direction from the pixel of the compressed video positioned at (i, j).

The normalization parameters α_L, α_R, α_U, and α_D are integers and are stored in a memory.

QP(f(i, j)) is the size of quantization of the pixel positioned at (i, j) encoded to intra macroblocks, which is calculated by quantizer A of the H.26L compression type as described in the conventional art.

The quantization error of each pixel is proportional to the function of a quantization variable set in macroblock unit, and a blocking effect occurring in block margins has a higher degree of non-uniformity than a ring effect in intra blocks. Thus, the values of the normalization parameters α_L, α_R, α_U, and α_D can be obtained by the set theory saying that such characteristics must controlled according to the position information of each pixel, by selling the normalization parameters for controlling the degree of smoothing as a large value.

In a case that the compressed video is restored by dividing the same into blocks, it is often the case that the degree of non-uniformity of pixels adjacent to block marginal portions is higher than the degree of non-uniformity of pixels in intra blocks. In a case that the loop filter of the video decoding unit 300 and video decoding unit 300 restores the compressed video, the prediction residual between the motion compensated video and the original video is increased for thus excessively smoothing the compressed video. Thus, loop filtering of the pixel positioned in block margins encoded to the intra macroblocks is performed, thus reducing the excessive smoothing of the compressed video.

At this time, the normalization parameters α_L, α_R, α_U, and α_D that determine the degree of smoothing of a pixel in the left, right, upper, and downward directions from the original pixel of the compressed video positioned at (i, j) are determined by constant values K_L, K_R, K_U, and K_D. K_L, K_R, K_U and K_D are determined by experimental values obtained by the loop filter of the video decoding unit 300.

The equations for obtaining K_L, K_R, K_U and K_D are as follows.
K_L(f(i,j))=[2, if j mod 4=0; 0, otherwise]  (13)
K_R(f(i,j))=[2, if j mod 4=3; 0, otherwise]  (14)
K_U(f(i,j))=[2, if i mod 4=0; 0, otherwise]  (15)
K_D(f(i,j))=[2, if i mod 4=3; 0, otherwise]  (16)

Using the constant K determined by the above method and the normalization parameters, the compressed video signal is filtered by the video decoding unit 302 for thereby restoring the original pixel f(i, j).

However, the above loop filtering method is disadvantageous in that floating points are operated to thus increase computational complexity. To solve the above problem, the denominator and the numerator in the equation for obtaining the original video signal are respectively made into an integer by multiplying both denominator and numerator by 2⁸=256, thus reducing the computational complexity.

The above description will be expressed by
f(i,j)=[(2¹⁰−β_TOT)g(i,j)+β_L(f(i, j))g(i, j−1)+β_R(f(i, j))g(i, j+1)+β_U(f(i, j))g(i−1, j)+β_D(f(i, j))g(i+1, j)]/(2¹⁰)   (17)
β_TOT(f(i, j)=β_L(f((i, j))+β_R(f(i, j))+β_U(f(i, j))+β_D(f(i, j))   (18)
β_L(f(i, j))=2⁸α_L(f(i, j))=2⁸[K_L(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_L(f(i, j))QP²(f(i, j))]  (19)
β_R(f(i, j))=2⁸α_R(f(i, j))=2⁸[K_R(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_R(f(i, j))QP²(f(i, j))]  (20)
β_U(f(i, j))=2⁸α_U(f(i, j))=2⁸[K_U(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_U(f(i, j))QP²(f(i, j))]  (21)
β_D(f(i, j))=2⁸α_D(f(i, j))=2⁸[K_D(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_D(f(i, j))QP²(f(i, j))]  (22)

β_TOT(f(i, j)) is the sum of normalization parameters that determine the degree of smoothing of a pixel adjacent to the pixel of the compressed video positioned at (i, j).

β_L(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the left direction from the pixel of the compressed video positioned at (i, j).

β_R(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the right direction from the pixel of the compressed video positioned at (i, j).

β_U(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the upper direction from the pixel of the compressed video positioned at (i, j).

β_D(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the downward direction from the pixel of the compressed video positioned at (i, j).

As described above, when the denominator and numerator multiplied by 2⁸=256, floating points of the denominator and numerator are removed, whereby the equation becomes simpler and computing speed becomes improved by 3˜9 times.

In addition, in the above equation, since the loop filter does not need to perform division operation, the pixel restored by the equation can be obtained by moving the pixel before being multiplied by 2⁸ by 10 bits, thus acquiring the gain of computational complexity.

In addition, by storing the normalization parameters β_L, β_R, β_D, and β_L in a look-up table, computational complexity can be much reduced by reading out the stored normalization parameters from the look-up table without calculating the difference between adjacent pixels and the size of quantization.

As described above, by using the loop filter of the video decoding unit 300 and video decoding unit 300, the prediction residual is decreased, and thus a blocking effect and ring effect are reduced. However, the blocking effect still remains. In order to reduce the remaining blocking effect and ring effect, the post filter of the blocking elimination filter 400 is used.

The post filter restores signal close to the original video by eliminating the blocking effect and ring effect that are not processed by the loop filter.

The post filter performs filtering in the same manner as the above-described loop filter, except that it eliminates not the blocking effect and ring effect of margins between pixels, but the blocking effect and ring effect of all pixels.

Hence, the functional equation for obtaining the original pixel f(i, j) in the post filter is the same as the functional equation for obtaining the original pixel in the loop filter, except for the constant value K of the normalization parameters that determine the degree of smoothing of the original pixel.

The constant value K is determined by experimental values.

The equation for obtaining the original pixel f(i, j) is as follows.
f(i, j)=[(2¹⁰−β_TOT)g(i, j)+β_L(f(i, j))g(i, j−1)+β_R(f(i, j))g(i, j+1)+β_U(f(i, j))g(i−1, j)+β_D(f(i, j))g(i+1, j)]/(2¹⁰)   (23)
β_TOT(f(i, j))=β_L(f(i, j))+β_R(f(i, j))+β_U(f(i, j))+β_D(f(i, j))   (24)
β_L(f(i, j))=2⁸α_L(f(i, j))=2⁸[K_L(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_L(f(i, j))QP²(f(i, j))]  (25)
β_R(f(i, j))=2⁸α_R(f(i, j))=2⁸[K_R(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_R(f(i, j))QP²(f(i, j))]  (26)
β_U(f(i, j))=2⁸(f(i, j))=2⁸[K_U(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_U(f(i, j))QP²(f(i, j))]  (27)
β_D(f(i, j))=2⁸α_D(f(i, j))=2⁸[K_D(f(i, j))QP²(f(i, j))]/[[g(i, j)−g(i, j−1)]²+K_D(f(i, j))QP²(f(i, j))]  (28)
K_L(f(i, j))=[2, if j mod 4=0; 1/2, otherwise]  (29)
K_R(f(i, j))=[2, if j mod 4=3; 1/2, otherwise]  (30)
K_U(f(i, j))=[2, if i mod 4=0; 1/2, otherwise]  (31)
K_D(f(i, j))=[2, if i mod 4=3; 1/2, otherwise]  (32)

β_TOT(f(i, j) is the sum of normalization parameters that determine the degree of smoothing of a pixel adjacent to the pixel of the compressed video positioned at (i, j).

β_L(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the left direction from the pixel of the compressed video positioned at (i, j).

β_R(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the right direction from the pixel of the compressed video positioned at (i, j).

β_U(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the upper direction from the pixel of the compressed video positioned at (i, j).

β_D(f(i, j)) is a normalization parameter that determine the degree of smoothing of a pixel in the downward direction from the pixel of the compressed video positioned at (i, j).

K_L, K_R, K_U, and K_D are constant values of normalization parameter α in case of post filtering.

In case of using the loop/post filter, the compressed video signal is restored to the original video signal by the post filtering equation to be outputted, whereby the prediction residual is reduced for thereby increasing compression efficiency, and reducing a blocking effect and ring effect without excessive smoothing.

As described above, in the present invention, a blocking effect and ring effect of the H.26L moving video compression type can be eliminated, and a more improved video quality can be acquired by applying the method for restoring the original pixel by the normalization restoration method to the system employing the H.26L compression.

In addition, the normalization parameters that determine the degree of smoothing can be stored in the look-up table and can be detected according to the difference between pixels adjacent to the original pixel and the size of quantizaiton, whereby the equation for restoring the compressed moving video, resulting in excessive smoothing, becomes simpler, and filtering control is made possible by a simple equation, thus making a high speed real time video processing possible.

As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

1. A method for reducing a blocking effect in a compressed video signal, comprising:

the decoding step of restoring a motion compensated video signal to an original video signal by reducing the prediction residual between the motion compensated video signal and the original video signal and the blocking effect; and

the post-filtering step of performing post-filtering in a blocking elimination filter to reduce a blocking effect and ring effect remained in the compensated signal, wherein the decoding step comprises,

considering the direction of a pixel adjacent to the original pixel of the video signal to be restored,

defining an additional function of the reliability and degree of smoothing of each pixel adjacent to the original pixel,

obtaining a normalization parameter α that gives a weight value to the reliability and degree of smoothing of the original video signal using the additional function,

calculating a pixel to be restored according to the normalization parameter α, compressed video signal, and size of quantization using a function, and

designating values of the normalization parameter α by differently setting the degree of smoothing based on the position of the pixel to be restored in response to the position of the reference pixel.

2. The method according to claim 1, wherein the decoding step comprises:

designating constant values of the normalization parameter α that differently setting the degree of smoothing based on the position of the pixel to be restored in response to the position of the reference pixel and the form of a filter;

applying a 8-bit value to the function for calculating the pixel to be processed; and

performing loop filtering of the pixel positioned in block margins encoded to intra macroblock in a decoding unit.

3. The method according to claim 1, wherein the pixel to be restored is calculated by:

f(i,j)=[(4−α_TOTg(i,j)+α_L(f(i,j))g(i,j−1)+α_R(f(i,j))g(i,j+1)+α_U(f(i,j))g(i−1,j)+α_Df(i,j))g(i+1,j)]/4

α_TOT(f(i,j))=α_L(f(i,j))+α_R(f(i,j)+α_U(f(i,j))+α_Df(i,j)),

4. The method according to claim 3, wherein the normalization parameter for each pixel is obtained by:

α_L(f(i,j)=[K_LQP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_LQP²(f,(i,j))]

α_R(f(i,j)=[K_RQP²(f(i,j))]/[[g(i,j)−g(i,j+1)]²+K_RQP²(f,(i,j))]

α_U(f(i,j)=[K_UQP²(f(i,j))]/[[g(i,j)−g(i−1,j)]²+K_UQP²(f,(i,j))]

α_D(f(i,j)=[K_DQP²(f(i,j))]/[[g(i,j)−g(i+1,j)]²+K_DQP²(f(i,j))]

5. The method according to claim 4, wherein the size of quantization of the pixel positioned at (i, j) encoded to intra macroblocks is obtained by QP(f(i,j))=[676]/[A(f(i, j))], in which A is a quantizer, and QP(f(i, j)) is calculated by the quantizer defined in the H.26L compression method.

6. The method according to claim 4, wherein the constant value K of the normalization parameter is obtained by experimental values by:

K_L(f(i,j))=[2, if j mod 4=0; 0, otherwise]

K_R(f(i,j))=[2, if j mod 4=3; 0, otherwise]

K_U(f(i,j))=[2, if i mod 4=0; 0, otherwise]

K_D(f(i,j))=[2, if i mod 4=3; 0, otherwise].

7. The method according to claim 1, wherein a pixel to be processed is expressed by applying a 8-bit value by:

f(i, j)=[(2¹⁰−β_TOT)g(i, j)+β_L(f(i, j))g(i, j−1)+β_R(f(i, j))g(i, j+1)+β_U(f(i, j))g(i−1, j)+β_D(f(i, j))g(i+1, j)]/(2¹⁰) β_TOT(f(i, j))=β_L(f(i, j))+β_R(f(i, j))+β_U(f(i, j))+β_D(f(i, j))

8. The method according to claim 7 wherein each of the normalization parameters is obtained by:

β_L(f(i,j))=2⁸α_L(f(i,j))=2⁸[K_L(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_L(f(i,j))QP²(f(i,j))]

β_R(f(i,j))=2⁸α_R(f(i,j))=2⁸[K_R(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_R(f(i,j))QP²(f(i,j))]

β_U(f(i,j))=2⁸α_U(f(i,j))=2⁸[K_U(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_U(f(i,j))QP²(f(i,j))]

β_D(f(i,j))=2⁸α_D(f(i,j))=2⁸[K_D(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_D(f(i,j))QP²(f(i,j))],

9. The method according to claim 1, wherein the post-filtering step comprises the steps of:

defining an additional function of a pixel to be restored of a signal decoded by means of loop-filtering of the video signal decoding unit;

determining the constant value of the normalization parameter that differently sets the reliability and degree of smoothing of all pixels with respect to the original video signal; and

performing post-filtering by the function for calculating the pixel to be restored containing the determined constant value.

10. The method according to claim 9, wherein the constant value of the normalization parameter that differently sets the reliability and degree of smoothing of all pixels with respect to the original video signal is determined by experimental values, and is calculated by:

K_L(f(i,j))=[2, if j mod 4=0; ½, otherwise]

K_R(f(i,j))=[2, if j mod 4=3; ½, otherwise]

K_U(f(i,j))=[2, if i mod 4=0; ½, otherwise]

K_D(f(i,j))=[2, if i mod 4=3; ½, otherwise]

11. The method according to claim 1, wherein each of the normalization parameters is obtained by:

β_L(f(i,j))=2⁸α_L(f(i,j))=2⁸[K_L(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_L(f(i,j))QP²(f(i,j))]

β_R(f(i,j))=2⁸α_R(f(i,j))=2⁸[K_R(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_R(f(i,j))QP²(f(i,j))]

β_U(f(i,j))=2⁸α_U(f(i,j))=2⁸[K_U(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_U(f(i,j))QP²(f(i,j))]

β_D(f(i,j))=2⁸α_D(f(i,j))=2⁸[K_D(f(i,j))QP²(f(i,j))]/[[g(i,j)−g(i,j−1)]²+K_D(f(i,j))QP²(f(i,j))],

12. A method for reducing a blocking effect in a compressed video signal, comprising:

the decoding step of restoring a motion compensated video signal to an original video signal by reducing the prediction residual between the motion compensated video signal and the original video signal and the blocking effect; and

the post-filtering step of performing post-filtering in a blocking elimination filter to reduce a blocking effect and ring effect remained in the compensated signal, wherein a pixel to be processed is expressed by applying a 8-bit value by:

f(i,j)=[(2¹⁰−β_TOT)g(i,j)+β_L(f(i,j))g(i,j−1)+β_R(f(i,j))g(i,j+1)+β_U(f(i,j))g(i−1,j)+β_Df(i,j))g(i+1,j)]/2¹⁰

β_TOT(f(i,j))=β_L(f(i,j))+β_R(f(i,j))+β_U(f(i,j))+β_U(f(i,j))

13. A method for reducing a blocking effect in a video signal by a video decoding apparatus, the method comprising:

receiving, by the video decoding apparatus, a compressed video signal; and

generating, by the video decoding apparatus, a reconstructed video signal from the compressed video signal;,

wherein said generating the reconstructed video signal comprises deblocking filtering including:

obtaining at least one parameter determining degree of smoothing information for a pixel to be filtered using a look-up table based on quantization information of a region including the pixel to be filtered, and the at least one parameter being stored in the look-up table and being identified from the look-up table using the quantization information, the quantization information being a quantization parameter (QP) applied to transform coefficient information in a frequency domain,

obtaining a value of the pixel to be filtered based on the degree of smoothing information at least one parameter, information regarding a first adjacent pixel, and information regarding a second opposing adjacent pixel, and

obtaining the reconstructed video signal based at least in part on the value obtained for the pixel to be filtered.

14. The method of claim 13, wherein said obtaining the at least one parameter determining the degree of smoothing information comprises retrieving predetermined normalization parameters from the look-up table.

15. The method of claim 13, wherein the first and second adjacent pixels are located in a horizontal direction with respect to the pixel to be filtered.

16. The method of claim 13, wherein the first and second adjacent pixels are located in a vertical direction with respect to the pixel to be filtered.

17. The method of claim 13, wherein the information regarding the first adjacent pixel comprises a difference between the pixel to be filtered and the first adjacent pixel and the information regarding the second adjacent pixel comprises a difference between the pixel to be filtered and the first adjacent pixel and a difference between the pixel to be filtered and the second adjacent pixel.

18. The method of claim 13, further comprising obtaining the at least one parameter determining the degree of smoothing information based on constant values, the constant values being determined by experimentally-determined values obtained by a loop filter.

19. An apparatus for reducing a blocking effect in a video signal, the apparatus comprising a deblocking filter connected for use in generating a reconstructed video signal from a compressed video signal, wherein the deblocking filter is configured to determine obtain at least one parameter determining degree of smoothing information for a pixel to be filtered using a look-up table based on quantization information of a region including the pixel to be filtered and, the at least one parameter being stored in the look-up table and being identified from the look-up table using the quantization information, the quantization information being a quantization parameter (QP) applied to transform coefficient information in a frequency domain, to obtain a value of the pixel to be filtered based on the degree of smoothing information at least one parameter, information regarding a first adjacent pixel, and information regarding a second opposing adjacent pixel, and to obtain the reconstructed video signal based at least in part on the value obtained for the pixel to be filtered.

20. The apparatus of claim 19, wherein the deblocking filter is configured to retrieve pre-determined normalization parameters from the look-up table.

21. The apparatus of claim 19, wherein the first and second adjacent pixels are located in a horizontal direction with respect to the pixel to be filtered.

22. The apparatus of claim 19, wherein the first and second adjacent pixels are located in a vertical direction with respect to the pixel to be filtered.

23. The apparatus of claim 19, wherein the information regarding the first adjacent pixel comprises a difference between the pixel to be filtered and the first adjacent pixel and the information regarding the second adjacent pixel comprises a difference between the pixel to be filtered and the first adjacent pixel and a difference between the pixel to be filtered and the second adjacent pixel.

24. The apparatus of claim 19, wherein the deblocking filter is configured to determine obtain the at least one parameter determining the degree of smoothing information based on constant values, the constant values being determined by experimentally-determined values obtained by a loop filter.

25. A method for reducing a blocking effect in a video signal, the method comprising:

receiving a compressed video signal; and

generating, by one or more processors, a reconstructed video signal from the compressed video signal;,

wherein said generating the reconstructed video signal comprises deblocking filtering including:

obtaining at least one parameter determining degree of smoothing information for a pixel to be filtered using a look-up table based on quantization information of a region including the pixel to be filtered, and the at least one parameter being stored in the look-up table and being identified from the look-up table using the quantization information, the quantization information being a quantization parameter (QP) applied to transform coefficient information in a frequency domain,

obtaining a value of the pixel to be filtered based on the degree of smoothing information at least one parameter, information regarding a first adjacent pixel, and information regarding a second opposing adjacent pixel, and

obtaining the reconstructed video signal based at least in part on the value obtained for the pixel to be filtered.

26. A method for reducing a blocking effect in a video signal by a video decoding apparatus, the method comprising:

receiving, by the video decoding apparatus, a compressed video signal;

identifying, by the video decoding apparatus, a pixel to be filtered;

determining, by the video decoding apparatus, quantization information of a region including the pixel to be filtered, the quantization information being a quantization parameter (QP) applied to transform coefficient information in a frequency domain;

accessing, by the video decoding apparatus, a look-up table;

obtaining, by the video decoding apparatus, at least one parameter determining, based on information identified from within the look-up table, a degree of smoothing information for the pixel to be filtered, the at least one parameter being stored in the look-up table and being identified from the look-up table using the quantization information;

accessing, by the video decoding apparatus, information regarding a first adjacent pixel;

accessing, by the video decoding apparatus, information regarding a second opposing adjacent pixel;

obtaining, by the video decoding apparatus, a value of the pixel to be filtered based on the degree of smoothing information determined at least one parameter, the information regarding the first adjacent pixel, and the information regarding the second opposing adjacent pixel; and

generating, by the video decoding apparatus, a reconstructed video signal based at least in part on the value obtained for the pixel to be filtered.

27. The method of claim 13, further comprising:

performing, by the video decoding apparatus, a post filtering of the reconstructed video signal in a same manner as said generating the reconstructed video signal.

28. The method of claim 13, wherein the deblocking filtering is performed for a pixel at a block boundary based on the at least one parameter.

29. The apparatus of claim 19, further comprising:

a post filter configured to perform a post filtering of the reconstructed video signal in a same manner as the deblocking filter.

30. The method of claim 25, wherein the deblocking filtering is performed for a pixel at a block boundary based on the at least one parameter.