Image decoding device, image decoding method, and program

Abstract

To improve coding efficiency.SOLUTION: An image decoding device 200 according to an invention comprises: an intra-prediction part 204 which generates first predictive pixels based on decoded pixels and control information; an accumulation part 208 which accumulates the decoded pixels; a motion compensation part 205 which generates second predictive pixels based on the decoded pixels accumulated in the accumulation part 208 and the control information; a correction part 206 which corrects the second predictive pixels corresponding to neighboring pixels and thereby generates third predictive pixels; and an adder 207 which adds a predictive residual and any one of the first to third predictive pixels to obtain decoded pixels.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image decoding apparatus, an image decoding method, and a program.

Background Art

[0002] Non-Patent Document 1 and Non-Patent Document 2 disclose local illumination compensation (LIC). LIC corrects decoded reference pixels to obtain a predicted value for a block to be decoded.

[0003] Specifically, as shown in FIG. 2, coefficients C1 and C2 are obtained by the least squares method from the neighboring pixels of the reference block indicated by the motion vector of the block to be decoded and the neighboring pixels of the block to be decoded, and are applied to the pixel Q of the reference block to be used as a predicted value P (= C1 × Q + C2).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Non-Patent Document 1 and Non-Patent Document 2, since prediction is performed using two coefficients, there is a problem that it can only cope with cases where pixels are linearly distributed and cannot cope with various pixel distributions.

[0006] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an image decoding apparatus, an image decoding method, and a program with high encoding efficiency.

Means for Solving the Problems

[0007] The first feature of the present invention is an image decoding apparatus, comprising: a decoding unit that decodes control information and quantization values; an inverse quantization unit that inverse quantizes the quantization values to obtain transform coefficients; an inverse transform unit that inverse transforms the transform coefficients to obtain a prediction residual; an intra prediction unit that generates a first prediction pixel based on the decoded pixel and the control information; an accumulation unit that accumulates the decoded pixels; a motion compensation unit that generates a second prediction pixel based on the decoded pixels accumulated in the accumulation unit and the control information; a correction unit that generates a third prediction pixel by correcting the second prediction pixel according to neighboring pixels; and an adder that adds the prediction residual and any one of the first to third prediction pixels to obtain a decoded pixel.

[0008] The second feature of the present invention is an image decoding method, comprising: a step of decoding control information and quantization values; a step of inverse quantizing the quantization values to obtain transform coefficients; a method of inverse transforming the transform coefficients to obtain a prediction residual; a step of generating a first prediction pixel based on the decoded pixel and the control information; a step of accumulating the decoded pixels; a step of generating a second prediction pixel based on the accumulated decoded pixels and the control information; a step of generating a third prediction pixel by correcting the second prediction pixel according to neighboring pixels; and a step of adding the prediction residual and any one of the first to third prediction pixels to obtain a decoded pixel.

[0009] A third feature of the present invention is a program that causes a computer to function as an image decoding device, the image decoding device including a decoding unit that decodes control information and quantization values, an inverse quantization unit that inverse quantizes the quantization values to obtain transform coefficients, an inverse transform unit that inverse transforms the transform coefficients to obtain prediction residuals, an intra prediction unit that generates a first predicted pixel based on decoded pixels and the control information, an accumulation unit that accumulates the decoded pixels, a motion compensation unit that generates a second predicted pixel based on the decoded pixels accumulated in the accumulation unit and the control information, a correction unit that generates a third predicted pixel by correcting the second predicted pixel according to neighboring pixels, and an adder that adds the prediction residual and any one of the first to third predicted pixels to obtain a decoded pixel.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide an image decoding device, an image decoding method, and a program with high coding efficiency.

Brief Description of the Drawings

[0011]

Figure 1

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Figure 8

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the components in the following embodiments can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. Therefore, the description of the following embodiments does not limit the content of the invention described in the claims.

[0013] <First Embodiment> Hereinafter, with reference to FIGS. 1 to 8, an image decoding apparatus 200 according to the present embodiment will be described. FIG. 1 is a diagram showing an example of a functional block of the image decoding apparatus 200 according to the present embodiment.

[0014] As shown in FIG. 1, the image decoding apparatus 200 includes a code input unit 210, a decoding unit 201, an inverse quantization unit 202, an inverse transform unit 203, an intra prediction unit 204, a motion compensation unit 205, a correction unit 206, an adder 207, an accumulation unit 208, and an image output unit 220.

[0015] The code input unit 210 is configured to acquire coded information coded by an image coding apparatus.

[0016] The decoding unit 201 is configured to decode control information and quantization values from the coded information input from the code input unit 210. For example, the decoding unit 201 is configured to output control information and quantization values by performing variable length decoding on such coded information.

[0017] Here, the quantization value is sent to the inverse quantization unit 202, and the control information is sent to the intra prediction unit 204, the motion compensation unit 205, and the correction unit 206. Note that such control information includes information necessary for controlling the inverse quantization unit 202, the intra prediction unit 204, the motion compensation unit 205, the correction unit 206, etc., and may include header information such as a sequence parameter set, a picture parameter set, a picture header, and a slice header.

[0018] The inverse quantization unit 202 is configured to inverse quantize the quantization value sent from the decoding unit 201 to obtain a transform coefficient. Such a transform coefficient is sent to the inverse transform unit 203.

[0019] The inverse transform unit 203 is configured to inverse transform the transform coefficient sent from the inverse quantization unit 202 to obtain a prediction residual. Such a prediction residual is sent to the adder 207.

[0020] The intra prediction unit 204 is configured to generate a first prediction pixel for adding to the prediction residual by the adder 207 based on the decoded pixel obtained via the adder 207 and the control information decoded by the decoding unit 201. Such a first prediction pixel is sent to the adder 207.

[0021] The motion compensation unit 205 is configured to generate a second prediction pixel for adding to the prediction residual by the adder 207 based on the decoded pixel obtained by referring to the accumulation unit 208 and the control information decoded by the decoding unit 201. Such a second prediction pixel is sent to the adder 207 or the correction unit 206.

[0022] The accumulation unit 208 is configured to cumulatively accumulate the decoded pixel sent from the adder 207. Such a decoded pixel receives a reference from the motion compensation unit 205 via the accumulation unit 208.

[0023] The adder 207 is configured to add the prediction residual sent from the inverse conversion unit 203 and any one of the first to third predicted pixels input from the intra prediction unit 204, the motion compensation unit 205, and the correction unit 206 to obtain a decoded pixel. Such a decoded pixel is sent to the image output unit 220, the storage unit 208, and the intra prediction unit 204.

[0024] The image output unit 220 outputs the decoded pixel sent from the adder 207.

[0025] (Correction Unit 206) Hereinafter, an example of the correction of the second predicted pixel by the correction unit 206 will be described.

[0026] The role of the correction unit 206 is to derive a weight coefficient for the optimal predicted pixel for the decoding target block in order to compensate the decoding target block with high accuracy in the subsequent adder 207, and correct the input predicted pixel according to the weight coefficient.

[0027] The correction unit 206 corrects the second predicted pixel by applying a polynomial to the reference pixel.

[0028] For example, when the correction unit 206 generates a correction value P(x, y) as a predicted value at coordinates (x, y) in the decoding target block from the reference pixel Q(x, y), it defines a polynomial by the following equation using weight coefficients C1 and C2.

[0029] P(x, y) = C1 × Q(x, y) + C2 Alternatively, the correction unit 206 can also correct the second predicted pixel by applying a polynomial to a plurality of reference pixels.

[0030] For example, when the correction unit generates a correction value P(x, y) as a predicted value at coordinates (x, y) in the decoding target block from different reference pixels Q(x, y) and R(x, y), it defines a polynomial by the following equation using weight coefficients C1, C2, and C3.

[0031] P(x, y) = C1 × Q(x, y) + C2 × R(x, y) + C3 Alternatively, the correction unit 206 may define a polynomial using a plurality of reference pixels Q1, Q2, …, Q n The following equation is an example of defining a polynomial using weighting coefficients C1, C2, … C in a 3×3 region centered on the coordinates (x, y). 10

[0032] P(x, y) = C1 × Q(x - 1, y - 1) + C2 × Q(x, y - 1) + C3 × Q(x + 1, y - 1) + C4 × Q(x - 1, y) + C5 × Q(x, y) + C6 × Q(x + 1, y) + C7 × Q(x - 1, y + 1) + C8 × Q(x, y + 1) + C9 × Q(x + 1, y + 1) + C 10 Here, Q1 = Q(x - 1, y - 1), Q2 = Q(x, y - 1), Q3 = Q(x + 1, y - 1), Q4 = Q(x - 1, y), Q5 = Q(x, y), Q6 = Q(x, y + 1), Q7 = Q(x + 1, y - 1), Q8 = Q(x + 1, y), Q9 = Q(x + 1, y + 1).

[0033] FIG. 3 shows a case where there are 10 weighting coefficients. However, for simplicity of notation, Q(x + i, y + i) is represented as Q i,j

[0034] When the correction unit 206 uses a plurality of reference pixels, it is desirable to use nearby pixels.

[0035] Alternatively, the correction unit 206 may define a polynomial using values obtained by non-linearly transforming the reference pixels. The following equation is an example of defining a polynomial using the square term of Q(x, y) and in the regions above, below, left, and right centered on the coordinates (x, y).

[0036] P(x, y) = C1 × Q(x, y - 1) + C2 × Q(x - 1, y) + C3 × Q(x, y) + C4 × Q(x + 1, y) + C5 × Q(x, y + 1) + C6 × Q(x, y) × Q(x, y) + C7 ​​Alternatively, the correction unit 206 may define a plurality of polynomials based on the distribution of reference pixels. The following equations are examples of defining polynomials with two types of coefficients using a threshold Th when the histogram of reference pixels is bimodal.

[0037] P(x, y) = C1 × Q(x, y) + C2, P(x, y) > Th P(x, y) = C3 × Q(x, y) + C4, P(x, y) ≤ Th The correction unit 206 can be set to a value that separates the two peaks for the threshold Th. Alternatively, the correction unit 206 can be simplified to use, as the threshold Th, the average value of at least one of the neighboring pixels or reference pixels. If the distribution of reference pixels is multimodal, the correction unit 206 can also apply polynomials with more types of coefficients.

[0038] Here, by simplifying the polynomial, an effect of reducing the computational load can be obtained. Conversely, by making the polynomial more complex, an effect of improving the prediction accuracy can be obtained. Furthermore, by defining a plurality of polynomials and making them selectable, an appropriate polynomial can be utilized, and an effect of improving the coding efficiency can be obtained.

[0039] At this time, the correction unit 206 may select a polynomial using control information that explicitly specifies the polynomial to be used for prediction among the plurality of polynomials, or may implicitly select a polynomial.

[0040] When the correction unit 206 implicitly selects a polynomial, it selects a polynomial according to at least one of the neighboring pixels and reference pixels.

[0041] For example, the correction unit 206 can select, as such a polynomial, a polynomial with a small error when applied to neighboring pixels.

[0042] Alternatively, when there are many coefficients in the polynomial, since a relatively large number of neighboring pixels are required for calculating the coefficients, in a flat region where the spatial correlation with the block to be decoded is maintained, there is a tendency to be able to derive an optimal coefficient. Therefore, a polynomial may be selected based on whether at least one of the neighboring pixels and the reference pixels is a flat region.

[0043] For whether at least one of the neighboring pixels and the reference pixels is a flat region, the correction unit 206 can determine based on whether the variance of at least one of the neighboring pixels and the reference pixels or the difference between specific pixels is greater than or less than a predetermined threshold value.

[0044] For example, when the difference between the pixels farthest apart among the neighboring pixels (between the bottom-left pixel and the top-right pixel) is less than the threshold value, the correction unit 206 determines that at least one of the neighboring pixels and the reference pixels is a flat region and selects a polynomial with n = 10. Otherwise, it determines that at least one of the neighboring pixels and the reference pixels is not a flat region and selects a polynomial with n = 2.

[0045] According to such a configuration, control information for selecting a polynomial is not required, and an optimal polynomial can be adaptively applied, so that an effect of improving the coding efficiency can be obtained.

[0046] As shown in FIG. 4, the correction unit 206 derives a weight coefficient from the neighboring pixels of the block to be decoded and the neighboring pixels of the reference block.

[0047] Specifically, the correction unit 206 derives a weight coefficient C such that the neighboring pixel P' of the block to be decoded and the neighboring pixel Q' of the reference block match by correction (FIG. 4(1)). For example, the correction unit 206 defines an error function E of the following formula and derives a weight coefficient C that minimizes E.

[0048] E = Σ(P’(x,y) - (C1 × Q’(x - 1,y - 1) + C2 × Q’(x,y - 1) + C3 × Q’(x + 1,y - 1) + C4 × Q’(x - 1,y) + C5 × Q’(x,y) + C6 × Q’(x + 1,y) + C7 × Q’(x - 1,y + 1) + C8 × Q’(x,y + 1) + C9 × Q’(x + 1,y + 1) + C 10 )) 2 The correction unit 206 may use the least squares method or the like to derive the weight coefficient C. Alternatively, the correction unit 206 can also derive the weight coefficient by using robust estimation such as principal component regression or partial least squares regression in order to reduce the influence of outliers.

[0049] The correction unit 206 applies the weight coefficient C to the neighboring pixels Q in the vicinity of the reference block (Fig. 4(2)) to obtain a correction value P, and uses it as the predicted value of the block to be decoded (Fig. 4(3)).

[0050] In this way, by deriving the weight coefficient from the neighboring pixels, it is not necessary to decode the weight coefficient, and thus the effect of improving the coding efficiency can be obtained.

[0051] Here, the correction unit 206 uses neighboring pixels within a certain distance range as the neighboring pixels P’ and Q’ used to derive the weight coefficient.

[0052] For example, as shown in Fig. 5(1), the correction unit 206 may derive the weight coefficient by using the neighboring pixels within 4 lines from the block to be decoded.

[0053] Conversely, the correction unit 206 can also limit the above-mentioned certain distance range. For example, as shown in Fig. 5(2), the correction unit 206 may derive the weight coefficient by using only the neighboring pixels in the area located above the block to be decoded, or as shown in Fig. 5(3), the correction unit 206 may derive the weight coefficient by using only the neighboring pixels in the area located to the left of the block to be decoded.

[0054] Note that the correction unit 206 can derive an appropriate weight coefficient by making it possible to select a plurality of ranges for designating neighboring pixels, and the effect of improving the coding efficiency can be obtained.

[0055] FIG. 6 shows an example in which the correction unit 206 derives different coefficients according to the distribution of reference pixels.

[0056] As shown in FIG. 6, first, the correction unit 206 calculates a threshold value Th from at least one of the neighboring pixels and reference pixels of the reference block.

[0057] Second, the correction unit 206 derives coefficients C1 and C2 by the least squares method or the like from the neighboring pixels below the threshold value Th and the neighboring pixels of the corresponding block to be decoded.

[0058] Similarly, the correction unit 206 derives coefficients C3 and C4 by the least squares method or the like from the neighboring pixels above the threshold value Th and the neighboring pixels of the corresponding block to be decoded.

[0059] Third, the correction unit 206 applies C1 and C2 to the reference pixels below the threshold value Th, and applies C3 and C4 to the reference pixels above the threshold value to calculate a predicted value P.

[0060] In this way, by applying different corrections according to the pixel distribution of the reference pixels, an effect of improving the prediction accuracy can be obtained.

[0061] Note that the correction unit 206 can apply another polynomial in a region where no reference pixels exist.

[0062] Hereinafter, the control information decoded by the decoding unit 201 regarding the above-described correction method will be described.

[0063] The coded information input to the image decoding apparatus 200 can include a sequence parameter set (SPS) that aggregates control information in units of sequences. Further, such coded information can include a picture parameter set (PPS) or a picture header (PH) that aggregates control information in units of pictures. Such coded information may include a slice header (SH) that aggregates control information in units of slices.

[0064] Next, with reference to FIG. 7, a method for setting a method of correcting a second predicted pixel in sequence units will be described.

[0065] As shown in FIG. 7, in step S101, the decoding unit 201 determines whether sps_lic_enabled_flag is 1. sps_lic_enabled_flag is a syntax for controlling the presence or absence of the above-described correction. When sps_lic_enabled_flag is 1, it indicates that the above-described correction is effective, and when sps_lic_enabled_flag is 0, it indicates that the above-described correction is ineffective.

[0066] In the case of Yes, this process proceeds to step S102, and in the case of No, this process ends.

[0067] In step S102, the decoding unit 201 decodes sps_lic_mode. sps_lic_mode is a syntax for controlling the above-described correction method.

[0068] By using sps_lic_mode, the correction method can be changed according to the image characteristics in sequence units, so an effect of maximizing the coding efficiency can be expected.

[0069] For example, for a sequence composed of CG, since it is easy to derive an optimal weight coefficient from neighboring pixels, it can be set to apply a polynomial with many weight coefficients. For a sequence composed of natural images, since it is difficult to derive an optimal weight coefficient from neighboring pixels, it can be set to apply a polynomial with few weight coefficients, and the coding efficiency can be maximized.

[0070] When setting a method for correcting a second predicted pixel in picture units, the decoding unit 201 similarly decodes pps_lic_enabled_flag and pps_lic_mode in the picture parameter set or the picture header.

[0071] By using the pps_lic_mode, the correction method can be changed according to the image characteristics for each picture, so that the effect of maximizing the coding efficiency can be expected.

[0072] For example, for a picture composed of CG, since it is easy to derive an optimal weight coefficient from neighboring pixels, it can be set to apply a polynomial with many weight coefficients. For a picture composed of natural images, since it is difficult to derive an optimal weight coefficient from neighboring pixels, it can be set to apply a polynomial with few weight coefficients, and the maximization of the coding efficiency can be achieved.

[0073] When setting the method for correcting the second predicted pixel for each slice, the decoding unit 201 decodes the sh_lic_enabled_flag and sh_lic_mode in the same way in the slice header.

[0074] By using the sh_lic_mode, the correction method can be changed according to the image characteristics for each slice, so that the effect of maximizing the coding efficiency can be expected.

[0075] For example, for a slice area composed of CG, since it is easy to derive an optimal weight coefficient from neighboring pixels, it can be set to apply a polynomial with many weight coefficients. For a slice area composed of natural images, since it is difficult to derive an optimal weight coefficient from neighboring pixels, it can be set to apply a polynomial with few weight coefficients, and the maximization of the coding efficiency can be achieved.

[0076] It is also possible to suppress an increase in the amount of code by setting only at the upper layer, or adaptive control can be achieved by setting at the lower layer and giving priority to the setting at the lower layer.

[0077] Alternatively, when the above correction method is set in advance, the decoding of such a correction method itself can be omitted.

[0078] Incidentally, in the above example, the method of setting the above correction method in sequence units, picture units, or slice units was described. However, without setting these, the method may be directly selected in block units described later. In this case, the above increase in header information can be avoided.

[0079] Hereinafter, with reference to FIG. 8, the method of setting the method of applying the above correction in block units will be described.

[0080] As shown in FIG. 8, in step S201, the decoding unit 201 determines whether sps_lic_enabled_flag, pps_lic_enabled_flag, or sh_lic_enabled_flag is 1.

[0081] If any of sps_lic_enabled_flag, pps_lic_enabled_flag, or sh_lic_enabled_flag is 1, this process proceeds to step S202. If none of sps_lic_enabled_flag, pps_lic_enabled_flag, or sh_lic_enabled_flag is 1, this process ends.

[0082] In step S202, the decoding unit 201 decodes cu_lic_mode, which is a control signal representing the above correction method.

[0083] In step S203, the decoding unit 201 determines whether there is one type of the above correction method.

[0084] If Yes, this process ends. If No, this process proceeds to step S204.

[0085] In step S204, the decoding unit 201 decodes cu_lic_idx, which is a control signal for specifying the correction method to be applied from among a plurality of correction methods.

[0086] cu_lic_idex is decoded to identify one of the correction methods set in the bottommost lic_mode applied to the block to be decoded.

[0087] According to this embodiment, since decoding is performed by correcting with an adaptive filter using neighboring pixels of the block to be decoded, the coding efficiency can be improved.

[0088] The above-described image decoding apparatus 200 may be realized by a program that causes a computer to execute each function (each process).

Industrial Applicability

[0089] Note that according to this embodiment, for example, since an improvement in overall service quality can be realized in moving image communication, it is possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

Explanation of Signs

[0090] 200…Image decoding apparatus 201…Decoding unit 202…Inverse quantization unit 203…Inverse transformation unit 204…Intra prediction unit 205…Motion compensation unit 206…Correction unit 207…Adder 208…Accumulation unit 210…Code input unit 220…Image output unit

Claims

1. An image decoding device, comprising: a decoding unit that decodes control information and quantization values; an inverse quantization unit that inverse quantizes the quantization values to obtain transform coefficients; an inverse transform unit that inverse transforms the transform coefficients to obtain prediction residuals; an intra prediction unit that generates a first predicted pixel based on decoded pixels and the control information; an accumulation unit that accumulates the decoded pixels; a motion compensation unit that generates a second predicted pixel based on the decoded pixels accumulated in the accumulation unit and the control information; a correction unit that generates a third predicted pixel by correcting the second predicted pixel according to neighboring pixels; an adder that adds the prediction residual and any one of the first to third predicted pixels to obtain a decoded pixel.

2. The image decoding device according to claim 1, wherein the correction unit corrects the second predicted pixel by applying a polynomial to a reference pixel.

3. The image decoding device according to claim 1, wherein the correction unit corrects the second predicted pixel by applying a polynomial to pixels of a plurality of reference destinations.

4. The correction unit: defines a polynomial using a plurality of reference pixels, and corrects the second predicted pixel using the polynomial.

5. The correction unit: defines a polynomial using values obtained by non-linearly transforming reference pixels, and corrects the second predicted pixel using the polynomial.

6. The correction unit: defines a plurality of polynomials according to the distribution of reference pixels, and corrects the second predicted pixel using the plurality of polynomials.

7. The correction unit: defines a plurality of polynomials in advance, and corrects the second predicted pixel using a polynomial selected from the plurality of polynomials.

8. The correction unit: corrects the second predicted pixel using a polynomial, and derives coefficients of the polynomial from neighboring pixels of a block to be decoded and neighboring pixels of a reference block.

9. The image decoding device according to claim 7, wherein the correction unit selects the polynomial according to at least one of neighboring pixels of a block to be decoded and reference pixels.

10. The image decoding device according to claim 9, wherein the correction unit selects, as the polynomial, a polynomial with a small error when applied to the neighboring pixels.

11. The image decoding device according to claim 9, wherein the correction unit selects the polynomial based on whether the neighboring pixels and the reference pixels are flat regions.

12. The correction unit derives a weight coefficient from the neighboring pixels of the block to be decoded and the neighboring pixels of the reference block, and corrects the second predicted pixel using a polynomial using the weight coefficient. The image decoding device according to claim 1.

13. The image decoding device according to claim 12, wherein the correction unit derives the weight coefficient using neighboring pixels within a certain distance range.

14. The image decoding device according to claim 13, wherein the correction unit limits the range of the neighboring pixels used for deriving the weight coefficient.

15. The image decoding device according to claim 14, wherein the correction unit limits the neighboring pixels used for deriving the weight coefficient to only the region located above or to the left of the block to be decoded.

16. An image decoding method, comprising: a step of decoding control information and quantization values; a step of inverse quantizing the quantization values to obtain transform coefficients; a method of inverse transforming the transform coefficients to obtain prediction residuals; a step of generating a first predicted pixel based on the decoded pixels and the control information; a step of accumulating the decoded pixels; a step of generating a second predicted pixel based on the accumulated decoded pixels and the control information; a step of generating a third predicted pixel by correcting the second predicted pixel according to neighboring pixels; and a step of adding the prediction residual and any one of the first to third predicted pixels to obtain a decoded pixel. An image decoding method characterized by comprising.

17. A program for causing a computer to function as an image decoding device, wherein the image decoding device comprises a decoding unit that decodes control information and quantization values, an inverse quantization unit that inverse quantizes the quantization values to obtain transform coefficients, an inverse transform unit that inverse transforms the transform coefficients to obtain prediction residuals, an intra prediction unit that generates a first predicted pixel based on the decoded pixels and the control information, an accumulation unit that accumulates the decoded pixels, a motion compensation unit that generates a second predicted pixel based on the decoded pixels accumulated in the accumulation unit and the control information A correction unit that generates a third predicted pixel by correcting the second predicted pixel according to neighboring pixels; A program characterized by comprising an adder that adds the prediction residual and any one of the first to third predicted pixels to obtain a decoded pixel.

Images